CN106458846A - Facilitated Imine Formation via Cationic Resin Catalysts - Google Patents

Abstract

Methods and systems for purifying crude aniline. The process can include contacting crude aniline, which can include aniline, water, and cyclohexanone, with a cation exchange resin to produce a low cyclohexanone-containing product that includes less cyclohexanone than the crude aniline. The cation exchange resin may be solid, semi-solid, or a combination thereof.

Description

Facilitated Imine Formation via Cationic Resin Catalysts

Cross References to Related Applications

This application claims priority to US Provisional Patent Application No. 61/947,733, filed March 4, 2014, which is incorporated herein by reference.

Background technique

technical field

The described embodiments generally relate to methods and systems for purifying crude aniline. More specifically, the described embodiments relate to methods and systems for reducing the concentration of cyclohexanone in crude aniline.

Description of prior art

Aromatic amines, including aniline, are precursors for the preparation of many industrial chemicals. The largest use of aniline is in the preparation of methylene diphenyl diisocyanate (MDI), which can be reacted with polyols to make polyurethanes. Aniline can be prepared by catalytic hydrogenation of nitrobenzene, as shown in Reaction 1.

Catalysts may include Raney nickel; palladium on carbon or nickel; or cobalt, copper or nickel on diatomaceous earth. However, reaction 1 can lead to the formation of impurities. One such impurity is cyclohexanone, which is difficult to physically remove from aniline. For example, aniline and cyclohexanone cannot be easily separated by distillation because aniline and cyclohexanone have similar boiling points.

Crude aniline comprising cyclohexanone can be reacted under acidic conditions to form an imine compound, or a Schiff base, cyclohexylidene aniline, as shown in Reaction 2.

The aniline can then be purified by removal of the higher molecular weight cyclohexyleneaniline. However, the reaction conditions of Reaction 2 are easily disturbed by upstream equipment and process conditions, which can lead to off-spec products.

Accordingly, there is a need for improved methods and systems for purifying crude aniline.

Description of drawings

Figure 1 depicts a schematic diagram of an illustrative purification system for producing purified aniline product from crude aniline, including a reactor upstream of a cation exchange resin unit, according to one or more embodiments described.

Figure 2 depicts a schematic diagram of another illustrative purification system for producing purified aniline product from crude aniline, including a reactor downstream of a cation exchange resin unit, according to one or more embodiments described .

Figure 3 depicts a schematic diagram of another illustrative purification system for producing purified aniline product from crude aniline, the purification system not including upstream or downstream of a cation exchange resin unit, according to one or more embodiments described of the reactor.

Figure 4 depicts a schematic diagram of an illustrative system for the production of aniline and the separation of impurities therefrom, according to one or more embodiments described.

detailed description

Methods and systems for purifying crude aniline are provided. The method may comprise contacting crude aniline with a cation exchange resin to produce a product containing a small amount of cyclohexanone, the crude aniline may include aniline, water and cyclohexanone, the product containing a small amount of cyclohexanone comprising Cyclohexanone with little crude aniline. Cation exchange resins can be solid, semi-solid, or combinations thereof.

It has been surprisingly and unexpectedly found that by using the heterogeneous reaction conditions of Reaction 2, in which a cationic resin catalyst or a cationic exchange resin is used to provide an acidic environment, cyclohexanone in the aniline feed or "crude aniline" The concentration can be significantly reduced by reacting cyclohexanone with aniline to produce cyclohexylideneaniline. Acidic cation exchange resins catalyze reactions without consuming cations. The cation exchange resin can reduce the concentration of cyclohexanone in the crude aniline by at least 10%, at least 20%, at least 30%, at least 50%, at least 70%, or at least 90%. For example, crude aniline can be contacted with a cation exchange resin to produce a product containing a small amount of cyclohexanone or to purify the aniline product with a cyclohexanone concentration reduced by about 30%, about 40%, compared to the crude aniline before contacting the cation exchange resin. %, or about 50% to about 70%, about 80%, about 90%, or about 95% or more. In another example, the cation exchange resin can reduce the concentration of cyclohexanone in crude aniline by about 10% to about 50%, about 20% to about 50%, about 30% to about 60%, about 40% to about 65%, about 50% to about 70%, about 50% to about 75%, about 60% to about 90%. In another example, the cation exchange resin can reduce the concentration of cyclohexanone in crude aniline comprising from about 100 ppmw to about 15,000 ppmw of cyclohexanone by at least 70%, at least 80%, at least 90%, or 95%. Cyclohexanone.

It has also been surprisingly and unexpectedly found that the cation exchange resin can reduce the concentration of cyclohexanone in crude aniline in a period of less than 60 minutes, less than 45 minutes, less than 30 minutes, or less than 15 minutes by at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95%. For example, the cation exchange resin can provide a concentration of cyclohexanone in the crude aniline of about 1 minute to about 15 minutes, about 5 minutes to about 20 minutes, about 15 minutes to about 30 minutes, about 25 minutes to about 40 minutes, about A reduction of at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90% over a period of 35 minutes to about 50 minutes, or about 40 minutes to about 60 minutes %, or at least 95%.

1 depicts a schematic diagram of an illustrative purification system 100 for producing a purified aniline product 134 from crude aniline 102, the illustrative purification system 100 including a reactor 110 that operates at a cation Upstream of the exchange resin unit 122 . The system may include, but is not limited to, one or more dehydration units, such as one or more dehydration columns 104, one or more cyclohexanone reduction reactors 110, one or more heat exchangers (both shown as 114, 118 ), one or more cation exchange resin units 122, and one or more separators, such as one or more distillation columns 130. Reactor 110 can operate under homogeneous reaction conditions. Crude aniline can be introduced via line 102 to dehydration unit 104 to produce dehydrated crude aniline via line 108 and to produce an overhead comprising water via line 106 . Crude aniline in line 102 can include, but is not limited to, aniline, water, mononitrobenzene, cyclohexanone, toluene, benzene, cyclohexanol, phenol, toluidine, methylcyclopentane, methylcyclohexane , cyclohexylamine, one or more amines, one or more ketones, or any mixture thereof.

The crude aniline in line 102 can have an aniline concentration ranging from a low of about 85 wt%, about 88 wt%, or about 92 wt% to a high of about 95 wt%, about 97 wt%, or about 99 wt%. The crude aniline in line 102 can have a water concentration ranging from a low of about 1 wt%, about 3 wt%, or about 5 wt% to a high of about 8 wt%, about 12 wt%, or about 15 wt%. The crude aniline in line 102 can have a concentration of cyclohexanone ranging from a low of about 100 parts per million by weight ("ppmw"), about 250 ppmw, about 500 ppmw, about 1,000 ppmw, or about 1,500 ppmw to a high of about 4,000 ppmw, About 6,000 ppmw, about 8,000 ppmw, or about 10,000 ppmw. The crude aniline in line 102 can have a total concentration of other impurities ranging from a low of about 100 ppmw, about 250 ppmw, about 500 ppmw, about 750 ppmw, or about 1,000 ppmw to a high of about 1,250 ppmw, about 1,500 ppmw, about 1,750 ppmw, or about 10,000 ppmw, Such other impurities may include, but are not limited to, benzene, toluene, phenol, mononitrobenzene, toluidine, cyclohexanol, cyclohexylamine, methylcyclopentane, methylcyclohexane, and/or cyclohexylene aniline.

Dehydration unit 104 can separate at least a portion of the water and/or other impurities from the aniline to produce dehydrated crude aniline via line 108 and an overhead comprising water via line 106 . The overhead product in line 106 comprising water can include, but is not limited to, water, toluene, benzene, cyclohexanol, phenol, methylcyclopentane, methylcyclohexane, cyclohexanone, cyclohexylamine, or any mixture. Dehydration unit 104 may comprise any system, device, or combination of systems and/or devices capable of separating at least a portion of the crude aniline introduced thereto via line 102 , including any water. For example, dehydration unit 104 may be or include one or more distillation columns or fractionation columns. The dehydration unit 104 can operate at a temperature of at least about 100°C up to about 215°C, which can evaporate at least a portion of the water and at least a portion of the one or more other impurities, such as toluene, Benzene, cyclohexanol, phenol, methylcyclopentane, methylcyclohexane, cyclohexanone, and/or cyclohexylamine, the boiling point of at least a portion of the water and at least a portion of one or more other impurities lower than the temperature in the dehydration unit 104.

The dehydration unit 104 can be empty, partially filled or completely filled with one or more materials to improve mass transfer and/or separation of water from crude aniline. For example, packing materials may include, but are not limited to, structural materials, random packing materials, trays, or any combination thereof. Two or more packing materials may be disposed within the dehydration unit 104 . For example, dehydration unit 104 may comprise random bulk packing, one or more trays, or combinations thereof.

Illustrative trays may include, but are not limited to, perforated plate trays, sieve trays, bubble cap trays, valve trays, fixed valve trays, tunnel trays, integral section trays, dual flow trays, integral Knuckle trays, snap-in valve trays, chimney trays, slit trays, or any combination thereof. As used in this application, the term "packing material" may include, but is not limited to, one or more structured and/or random materials disposed within the dewatering unit 104 . The packing material can increase the effective surface area within the dehydration unit 104 , which can improve mass transfer between liquid and/or gas phases within the dehydration unit 104 . The filler material can be made of any suitable metallic material. Illustrative examples of random packing materials may include, but are not limited to, Raschig rings, Lessing rings, I-rings, saddle rings, Interox saddle packings, Teller packings, Pall rings, U-rings, or any combination thereof. Illustrative examples of commercially available structured packings may include, but are not limited to, structured packings, corrugated sheets, crimped sheets, gauzes, grids, wire meshes, monolithic honeycomb structures, or any combination thereof.

The dehydrated crude aniline via line 108 can have an aniline concentration ranging from a low of about 98 wt%, about 98.5 wt%, or about 99 wt% to a high of about 99.5 wt%, about 99.9 wt%, or about 99.99 wt%. The dehydrated crude aniline via line 108 can have a water concentration ranging from a low of about 10 ppmw, about 100 ppmw, or about 200 ppmw to a high of about 1,000 ppmw, about 3,000 ppmw, or about 5,000 ppmw. The dehydrated crude aniline in line 108 can have a concentration of cyclohexanone ranging from a low of about 100 ppmw, about 250 ppmw, about 500 ppmw, about 750 ppmw, or about 1,000 ppmw to a high of about 2,000 ppmw, about 3,000 ppmw, about 4,000 ppmw, or about 5,000 ppmw . The dehydrated crude aniline in line 108 can have a total concentration of other impurities ranging from a low of about 50 ppmw, about 100 ppmw, about 500 ppmw, about 750 ppmw, or about 1,000 ppmw to a high of about 2,500 ppmw, about 3,500 ppmw, about 4,250 ppmw, or about 5,000 ppmw , the other impurities may include, but are not limited to, benzene, toluene, mononitrobenzene, phenol, toluidine, cyclohexanol, cyclohexylamine, methylcyclopentane, methylcyclohexane, and/or cyclic Hexylaniline.

The dehydrated crude aniline via line 108 can be introduced into reactor 110 and reacted in reactor 110 to produce cyclohexanone reduced product via line 112 which is The product of ketone reduction contains less cyclohexanone. Reactor 110 may be a homogeneous reactor, wherein a portion of cyclohexanone may react within reactor 110 to produce an imine compound, such as cyclohexylideneaniline, as shown in Reaction 2. For example, cyclohexanone can be reacted with the amine R- _NH2 in the presence of a catalyst such as sulfuric acid to reduce the concentration of cyclohexanone in the dehydrated crude aniline. For example, the cyclohexanone concentration in the dehydrated crude aniline can be reduced by an amount as low as about 10%, 20%, about 30%, or about 40% to as high as about 50%, about 60%, about 70%, about 80%, Or about 90%.

The product of cyclohexanone reduction in line 112 can have an aniline concentration of from a low of about 98 wt%, about 98.5 wt%, or about 99 wt% to a high of about 99.9 wt%, about 99.95 wt%, or about 99.99 wt%. The product of cyclohexanone reduction in line 112 can have a concentration of water from a low of about 10 ppmw, about 100 ppmw, or about 200 ppmw to a high of about 1,000 ppmw, about 3,000 ppmw, or about 5,000 ppmw. The product of reduction of cyclohexanone in line 112 can have a concentration of cyclohexanone ranging from a low of about 10 ppmw, about 50 ppmw, about 100 ppmw, about 300 ppmw, or about 500 ppmw to a high of about 1,000 ppmw, about 1,500 ppmw, about 2,000 ppmw, about 2,500 ppmw, or About 3,000ppmw. The product of reduction of cyclohexanone in line 112 can have a concentration of cyclohexylidene aniline ranging from a low of about 50 ppmw, about 100 ppmw, about 500 ppmw, about 750 ppmw, or about 1,000 ppmw to a high of about 2,500 ppmw, about 3,500 ppmw, about 4,250 ppmw, or about 5,000 ppmw. The product of cyclohexanone reduction in line 112 can have a total concentration of other impurities ranging from a low of about 50 ppmw, about 100 ppmw, about 500 ppmw, about 750 ppmw, or about 1,000 ppmw to a high of about 2,500 ppmw, about 3,500 ppmw, about 4,250 ppmw, or about 5,000 ppmw , the other impurities may include, but are not limited to, benzene, toluene, phenol, mononitrobenzene, toluidine, cyclohexanol, cyclohexylamine, methylcyclopentane, and/or methylcyclohexane.

The product of cyclohexanone reduction in line 112 can be introduced into one or more heat exchangers 114,118. The first heat exchanger 114 and the second heat exchanger 118 can be one or more of shell and tube, plate and frame, winding, U-shaped tube, bayonet heat exchanger, or any combination thereof or include shell and tube One or more of plate and frame, winding, U-shaped tube, bayonet heat exchanger, or any combination thereof. First heat exchanger 114 may cool the cyclohexanone reduction product recovered from reactor 110 via line 112 to produce a first cooled cyclohexanone reduction product via line 116 .

Second heat exchanger 118 can cool the first cooled cyclohexanone reduction product in line 116 to produce a second cooled cyclohexanone reduction product via line 120 . The pressure of the second cooled cyclohexanone reduction product in line 120 can be from about 300 kPa, or about 500 kPa to about 1,000 kPa, about 1,500 kPa, or about 2,000 kPa. The temperature of the second cooled cyclohexanone reduction product in line 120 can be as low as about 50°C, about 70°C, or about 90°C to as high as about 110°C, about 130°C, or about 150°C.

Heat may be transferred indirectly from the reaction products to one or more heat transfer media in the first and second heat exchangers 114, 118 to produce first and second cooled cyclohexanone reduction products via lines 116, 120, respectively, and heat from the first and the heat transfer medium of the second heat exchanger 114,118. Illustrative heat transfer media may include, but are not limited to, cooling water, boiler feed water, low pressure steam, medium pressure steam, ethylene glycol, products containing small amounts of cyclohexanone, air and/or other gaseous fluids, or any mixture thereof. The product of cyclohexanone reduction via line 112 can be cooled by direct contact or mixing (not shown) with a cooling fluid, such as water, to produce a cooled reaction product via lines 116,120. The product of cyclohexanone reduction via line 112 can be cooled by a combination of indirect heat exchange and direct contact cooling.

The cooled cyclohexanone reduction product via line 120 can be introduced to cation exchange resin unit 122 to produce a product containing a small amount of cyclohexanone via line 126 . The cation exchange resin unit 122 may include one or more cation exchange resin beds 124 . Cation exchange resin bed 124 may include any one or more of cation exchange resins that can catalyze the conversion of cyclohexanone molecules to imines, ie, cyclohexylidene aniline, as shown in Reaction 2. The cation exchange resin may include one or more ^of H ⁺ functionality, sulfuric acid, _HSO4- functionality, or any mixture or combination thereof. Cationic ion exchange resins may include, but are not limited to, one or more Ion exchange resins, available from Dow Water & Process Solution, one or more of series of ion exchange resins available from the Purolite Company, one or more of series of ion exchange resins available from the Lanxess Corp., or any mixture thereof. For example, the cation exchange resin may be or include a cross-linked styrene-divinylbenzene copolymer based polymer, which may contain sulfonic acid groups. For example, cation exchange resins may include, but are not limited to, 36, CT-151, 2629 or any mixture thereof.

Cation exchange resins can be solid, semisolid, or a combination of solid and semisolid structures. For example, the cation exchange resin may be in the form of solid particles, semi-solid particles, such as colloidal particles, or mixtures thereof. The cation exchange resin can be or include macroporous particles, microporous particles, or mixtures thereof. The solid cation exchange resin may be in the form of pellets, beads, granules, flakes, spheres, cubes, blocks, fibers, filaments, threads, or any mixture thereof. As used in this application, the terms "semi-solid" and "semi-solid particle" refer to a three-dimensional structure that is itself insoluble in a particular liquid. Three-dimensional structures are able to absorb and retain volumes of fluid, resulting in stable, often soft and pliable structures. Cation exchange resins can be solid and/or semi-solid structures configured in fixed beds, fluid or moving beds, or combinations thereof. In another example, the solid and/or semi-solid structure may be supported on one or more support members, such as rigid support members, between two or more support members, such as screens and plates, etc., or any combination.

The bed depth of the cation exchange resin disposed in the fixed bed can be as low as about 5 cm, about 10 cm, about 20 cm, about 30 cm, or about 40 cm to as high as about 70 cm, about 85 cm, about 100 cm, about 150 cm, about 200 cm, or about 300 cm. For example, the bed depth of the cation exchange resin disposed in a fixed bed can be from about 40 cm to about 80 cm, from about 50 cm to about 70 cm, from about 60 cm to about 120 cm, from about 60 cm to about 200 cm, or from about 90 cm to about 250 cm. A fixed bed comprising cation exchange resin may be disposed within cation exchange resin unit 122 . The cation exchange resin unit 122 may comprise or additionally comprise one, two, four, six, eight, ten, twelve, fifteen, twenty, or more discrete or individual fixed beds . Any number of cation exchange resin units each having any number of fixed bed arrangements therein may be arranged relative to each other in series, in parallel, or both. Between any two cation exchange resin units, the number of fixed beds, the size of the fixed beds, and the specific cation exchange resin arranged in each fixed bed may be the same or different.

Ion exchange materials such as ion exchange resins can have an average cross-sectional dimension or length of about 0.01 mm, about 0.05 mm, about 0.1 mm, about 0.3 mm, or about 0.5 mm to about 1 mm, about 2 mm, about 3 mm, about 5 mm, about 7mm, about 9mm, about 11mm, about 13mm, about 15mm, or about 20mm. The average pore size of ion exchange materials such as ion exchange resins can be as low as about 20 Angstroms about or about up to about about about or about For example, the average pore size of a cation exchange resin can be about to about or about to about or about to about The pore size of the ion exchange material, such as an ion exchange resin, can be as low as about 0.05 mL/g, about 0.1 mL/g, or about 0.15 mL/g to as high as about 0.3 mL/g, about 0.5 mL/g, or about 1 mL/g. For example, the cation exchange resin can have a pore size of about 0.15 mL/g to about 0.25 mL/g, about 0.2 mL/g to about 0.4 mL/g, or about 0.2 mL/g to about 1 mL/g. The surface area of the ion exchange material, such as an ion exchange resin, can be as low as about 10 m ² /g, about 15 m ² /g, or about 20 m ² /g to as high as about 30 m ² /g, about 40 m ² /g, or about 50 m ² /g.

Depending at least in part on the amount of the particular cation exchange resin and/or cyclohexanone present, the crude aniline in line 108, the product of cyclohexanone reduction in line 112, the first cooled cyclohexanone reduction product in line 116 and/or The second cooled cyclohexanone reduction product in line 120 can be contacted with a cation exchange resin at a rate of from about 0.1 ^m of crude aniline product per 1 m of cation exchange resin per hour to about 35 ^m of crude product per 1 m ^of cation exchange resin per hour. For example, the crude aniline in line 108, the product of cyclohexanone reduction in line 112, the first cooled cyclohexanone reduction product in line 116, and/or the second cooled cyclohexanone reduction product in line 120 can be combined with the cation The exchange resin is contacted at a rate of: a low of about 1 m ³ , about 3 m ³ , about 5 m ³ , or about 10 m ³ to a high of about 15 m ³ , about 20 m ³ , about 25 m ³ , or about 30 m ³ of crude product per 1 m ³ of cation exchange resin per hour. In another example, the crude aniline in line 108, the product of cyclohexanone reduction in line 112, the first cooled cyclohexanone reduction product in line 116, and/or the second cooled cyclohexanone reduction product in line 120 The product can be contacted with the cation exchange resin at a rate of from about 1 ^m to about 8 m ^of crude product per 1 m of ^cation exchange resin per hour, from about ² m to about ⁴ m of crude product per 1 m of ^cation exchange resin per hour , about 3m ³ to about 5m ³ crude product per 1m ^{3 cation} exchange resin per hour, about 4m ³ to about 6m ³ crude product per 1m ³ cation exchange resin per hour, about 10m ³ to about 27m ³ crude product per ^1m3 of cation exchange resin per hour. The cation exchange resin can remain in solid or semi-solid form when or after contact with: the crude aniline in line 108, the cyclohexanone reduction product in line 112, the first cooled cyclohexanone reduction product in line 116, and and/or second cooled cyclohexanone reduction product in line 120.

Depending at least in part on the particular ion exchange material, the crude aniline in line 102, the dehydrated crude aniline in line 108, the product of the cyclohexanone reduction in line 112, the first cooled cyclohexanone reduction product in line 116, and/or The second cooled cyclohexanone reduction product in line 120 can be introduced to cation exchange resin unit 122 and contacted with the cation exchange resin at a temperature ranging from a low of about 50°C, about 60°C, or about 70°C to a high of about 80°C, about 90°C. °C, about 100°C, about 110°C, about 120°C, about 130°C, about 140°C, about 150°C, or about 155°C. Depending at least in part on the particular cation exchange resin, the crude aniline in line 102, the dehydrated crude aniline in line 108, the product of the cyclohexanone reduction in line 112, the first cooled cyclohexanone reduction product in line 116, and/or The pressure of the second cooled cyclohexanone reduction product in line 120 when contacted with the cation exchange resin can be from a low of about 101 kPa, about 200 kPa, or about 500 kPa to a high of about 1,000 kPa, about 1,200 kPa, or about 2,000 kPa.

When the capacity of the cation exchange resin is nearly exhausted, eg, when the cation exchange resin no longer reacts with sufficient cyclohexanone present in the crude aniline, the cation exchange resin can be replaced with new ion exchange material. When the capacity of the cation exchange resin is nearly exhausted, the cation exchange resin can be regenerated. For example, the contact of crude aniline with the cation exchange resin can be stopped or diverted elsewhere, such as to other locations containing other cation exchange resins, and one or more regeneration materials can be contacted with the spent cation exchange resin to produce regenerated cation exchange resin, The regenerated cation exchange resin can be contacted again with: crude aniline in line 102, dehydrated crude aniline in line 108, cyclohexanone reduction product in line 112, first cooled cyclohexanone in line 116 reduction product, and/or the second cooled cyclohexanone reduction product in line 120.

The cation exchange resin unit 122 may be or include a vessel having ion exchange material, such as a cation exchange resin contained therein. The container of the cation exchange resin unit 122 can have various shapes including, but not limited to, cubes, rectangular boxes, cylinders, prisms, hyperboloid structures, or other shapes or combinations thereof. For example, the container can be a cylinder, the longitudinal axis of which can be oriented horizontally or at an angle relative to horizontal: about 1°, about 5°, about 10°, about 20°, or about 30° to about 60°, about 70°, or about 80°. The container may also have a longitudinal axis which may be oriented vertically or at an angle relative to the vertical of about 1°, about 5°, about 10°, about 20°, or about 30° to about 60°, about 70°, or about 80°. The cation exchange resin unit 122 or the longitudinal axis of the cation exchange resin unit 122 can be at least substantially horizontally oriented. The cation exchange resin unit 122 or the longitudinal axis of the cation exchange resin unit 122 can be at least substantially vertically oriented. As used in this application, the term "substantially perpendicular" refers to about -5° to about 5°, about -3° to about 3°, about -2° to about 2°, about -1° to about 1°, From about -0.1° to about 0.1°, or from about -0.0001° to about 0.0001°, relative to vertical.

The product in line 126 containing a small amount of cyclohexanone can have an aniline concentration ranging from a low of about 98 wt%, about 98.5 wt%, or about 99 wt% to a high of about 99.9 wt%, about 99.95 wt%, or about 99.99 wt%. The product in line 126 containing a small amount of cyclohexanone can have a water concentration ranging from a low of about 10 ppmw, about 100 ppmw, or about 200 ppmw to a high of about 1,000 ppmw, about 3,000 ppmw, or about 5,000 ppmw. The product in line 126 containing a small amount of cyclohexanone can have a cyclohexanone concentration ranging from a low of about 1 ppmw, about 10 ppmw, about 25 ppmw, or about 40 ppmw to a high of about 60 ppmw, about 70 ppmw, about 85 ppmw, or about 100 ppmw. For example, the low cyclohexanone-containing product via line 126 can have a cyclohexanone concentration of less than 150 ppmw, less than 100 ppmw, less than 50 ppmw, less than 40 ppmw, less than 30 ppmw, less than 20 ppmw, or less than 10 ppmw. The product in line 126 containing a small amount of cyclohexanone can have a concentration of cyclohexylidene aniline as low as about 50 ppmw, about 100 ppmw, about 500 ppmw, about 750 ppmw, or about 1,000 ppmw up to about 2,500 ppmw, about 3,500 ppmw, about 4,250 ppmw, or About 5,000ppmw. The product containing small amounts of cyclohexanone in line 126 can have a total concentration of other impurities ranging from a low of about 50 ppmw, about 100 ppmw, about 500 ppmw, about 750 ppmw, or about 1,000 ppmw to a high of about 2,500 ppmw, about 3,500 ppmw, about 4,250 ppmw, or about 5,000 ppmw, the other impurities may include, but are not limited to, benzene, toluene, phenol, mononitrobenzene, cyclohexanol, toluidine, cyclohexylamine, methylcyclopentane, and/or methylcyclohexane.

At least a portion of the product in line 126 containing a small amount of cyclohexanone may be used as a heat transfer medium to cool the cyclohexanone reduced product entering first heat exchanger 114, thereby producing a first cooled cyclohexanone reduced product via line 116 and The product containing a small amount of cyclohexanone is heated via line 128. Optionally, the product in line 126 containing a small amount of cyclohexanone can be bypassed through first heat exchanger 114 in line 128 . The pressure of the heated product containing a small amount of cyclohexanone can be as low as about 101 kPa, about 300 kPa, or about 500 kPa to as high as about 1,000 kPa, about 1,500 kPa, or about 2,000 kPa. The temperature of the heated cyclohexanone-containing minor product in line 128 can be as low as about 100°C, about 110°C, about 120°C, or about 130°C to as high as about 150°C, about 170°C, or about 200°C.

The minor cyclohexanone-containing product via line 126 and/or the minor cyclohexanone-containing product heated in line 128 can be separated in separator 130, such as via distillation, to separate impurities and produce a purified aromatic amine product. For example, the low-cyclohexanone-containing product via line 126 and/or the low-cyclohexanone-containing product heated in line 128 can be separated in separator 130 to produce a final or purified aniline product via line 134, and via line 132 Production of impurities including waste or numerous by-products. Impurities separated from purified aniline as waste via line 132 may include any compound and/or component other than aniline. Illustrative impurities may include, but are not limited to, imine compounds, mononitrobenzene, toluidine, phenol, or any mixture thereof.

The purified aniline product in line 134 can have a concentration of aniline ranging from a low of about 99 wt% to a high of about 99.99 wt%. The purified aniline product in line 134 can have an aniline concentration of at least 99 wt%, at least 99.4 wt%, or at least 99.5 wt% to about 99.9 wt% or about 99.95 wt%. The purified aniline product in line 134 can have a cyclohexanone concentration ranging from a low of about 1 ppmw, about 5 ppmw, about 10 ppmw, about 15 ppmw, about 20 ppmw, or about 30 ppmw to a high of about 50 ppmw, about 65 ppmw, about 75 ppmw, about 85 ppmw, or about 100 ppmw . The purified aniline product in line 134 can have a water concentration ranging from a low of about 10 ppmw, about 50 ppmw, about 100 ppmw, about 500 ppmw, about 750 ppmw, or about 1,000 ppmw to a high of about 2,500 ppmw, about 3,500 ppmw, about 4,250 ppmw, or about 5,000 ppmw . The purified aniline product in line 134 can have a concentration of cyclohexylidene aniline as low as about 1 ppmw, about 5 ppmw, about 10 ppmw, about 15 ppmw, about 20 ppmw, or about 30 ppmw to as high as about 50 ppmw, about 65 ppmw, about 75 ppmw, about 85 ppmw, or about 100ppmw. The purified aniline product in line 134 can have a total concentration of other impurities that can include, but are not limited to, Benzene, toluene, phenol, cyclohexanol, cyclohexylamine, mononitrobenzene, toluidine, methylcyclopentane, and/or methylcyclohexane.

Separator 130 may be similar to dehydration unit 104 . For example, separator 130 may comprise any system, device, or combination of systems and/or devices capable of separating at least a portion of the impurities in the dehydration product introduced thereto via line 128 from the aniline. For example, separator 130 may be or include one or more distillation columns or fractionation columns. Separator 130 can be empty, partially filled or fully filled with one or more trays and/or packing materials to improve mass transfer and/or separation of aniline from dehydration product.

A system for producing a purified aniline product can include a dehydration unit 104 configured to receive crude aniline via line 102 and produce dehydrated crude aniline. Dehydrated crude aniline can be recovered via one or more lines 108 connected to or in fluid communication with dehydration unit 104 and connected to reactor 110 or connected to Reactor 110 is in fluid communication. The first heat exchanger 114 can cool the cyclohexanone reduced product via line 112 to produce a first cooled cyclohexanone reduced product, which can be recovered via one or more lines 116, The one or more lines 116 are connected or in fluid communication with the first heat exchanger 114 and the second heat exchanger 118 . The second heat exchanger 118 can further cool the first cooled cyclohexanone reduction product which is recovered from the first heat exchanger 114 via line 216 to produce a second cooled cyclohexanone The ketone reduction product, the second cooled cyclohexanone reduction product, can be recovered via 120 .

The second cooled cyclohexanone reduction product via line 120 can be introduced to one or more cation exchange resin units 122 to produce a product containing a small amount of cyclohexanone. The cation exchange resin unit 122 may include one or more cation exchange resins 124 as described above. A product containing a small amount of cyclohexanone may be recovered via one or more lines 126 connected to or in fluid communication with the cation exchange resin unit 122 and connected to the first heat exchanger 114 Or in fluid communication with the first heat exchanger 114 . The product containing a small amount of cyclohexanone can be used as a heat transfer medium to cool the cyclohexanone reduction product entering the first heat exchanger 114 to produce a first cooled cyclohexanone reduction product via line 116 and can be passed through one or more The heated cyclohexanone-containing product is recovered in line 128 and one or more separators 130 , the one or more lines 128 being connected to or in fluid communication with the first heat exchanger 114 . Dehydration unit 104, first heat exchanger 114, second heat exchanger 118, cation exchange resin unit 122, reactor 110, and separator 30 may be as described above or elsewhere in this application.

The product via line 212 containing a small amount of cyclohexanone may be distilled or separated in separator 130 to produce a final or purified aniline product via line 234 and a waste or bulk by-product via line 232a. The purified aniline product via line 234 and waste via line 232 can be as described above and elsewhere in this application.

2 depicts a schematic diagram of another illustrative purification system 200 for producing a purified aniline product 234 from crude aniline 102, said another illustrative purification system 200 comprising a reactor 110 in a cation exchange resin unit 222. downstream. Purification system 200 may include one or more dehydration units 104, one or more heat exchangers 114, 118, one or more cation exchange resin units 222, one or more reactors 110, one or more separators 130, or any combination. The dehydrated crude aniline in line 108 can be introduced to heat exchanger 114 to produce a first cooled dehydrated crude aniline via line 216 .

The first cooled dehydrated crude aniline in line 216 can be introduced to a second heat exchanger 118 to produce a second cooled dehydrated crude aniline via line 220 . The temperature of the second cooled dehydrated crude aniline in line 220 can be as low as about 50°C, about 75°C, or about 100°C to as high as about 115°C, about 130°C, or about 150°C. The pressure of the second cooled dehydrated crude aniline in line 220 can be as low as about 300 kPa, about 500 kPa, about 750 kPa, or about 1,000 kPa to as high as about 1,250 kPa, about 1,500 kPa, about 1,750 kPa, or about 2,000 kPa.

The second cooled dehydrated crude aniline in line 220 can have the same or similar composition as the dehydrated crude aniline in line 108 described above with reference to FIG. 1 . The second cooled dehydrated crude aniline in line 220 can be introduced to a cation exchange resin unit 222 to produce a cyclohexanone reduced product via line 226 . Cation exchange resin unit 222 may include one or more cation exchange resin beds 124 and one or more cation exchange resins therein. The cation exchange resin unit 222 may be the same as or similar to the cation exchange resin unit described above with reference to FIG. 1 .

The products of the reduction of cyclohexanone in line 226 can include aniline, water, mononitrobenzene, phenol, toluidine, cyclohexanone, toluene, benzene, cyclohexanol, methylcyclopentane, methylcyclohexane, cyclohexane Amine, one or more amines, one or more ketones, or any mixture thereof. The product of cyclohexanone reduction in line 226 can have an aniline concentration ranging from a low of about 98 wt%, about 98.3 wt%, or about 98.5 wt% to a high of about 98.7 wt%, about 98.9 wt%, or about 99 wt%. The product of reduction of cyclohexanone in line 226 can have a water concentration of as low as about 10 ppmw, about 50 ppmw, about 100 ppmw, about 500 ppmw, about 750 ppmw, or about 1,000 ppmw to as high as about 2,500 ppmw, about 3,500 ppmw, about 4,250 ppmw, or about 5,000 ppmw. The product of cyclohexanone reduction in line 226 can have a concentration of cyclohexanone as low as about 10 ppmw, about 50 ppmw, about 100 ppmw, about 250 ppmw, about 500 ppmw, or about 750 ppmw up to about 1,250 ppmw, about 1,750 ppmw, about 2,250 ppmw, about 2,600 ppmw, or about 3,000ppmw. The product of reduction of cyclohexanone in line 226 can have a concentration of cyclohexylidene aniline ranging from a low of about 50 ppmw, about 100 ppmw, about 500 ppmw, about 750 ppmw, or about 1,000 ppmw to a high of about 2,500 ppmw, about 3,500 ppmw, about 4,250 ppmw, or about 5,000 ppmw. The product of cyclohexanone reduction in line 226 can have a total concentration of other impurities ranging from a low of about 50 ppmw, about 100 ppmw, about 500 ppmw, about 750 ppmw, or about 1,000 ppmw to a high of about 2,500 ppmw, about 3,500 ppmw, about 4,250 ppmw, or about 5,000 ppmw , the other impurities may include, but are not limited to, benzene, toluene, phenol, mononitrobenzene, toluidine, cyclohexanol, cyclohexylamine, methylcyclopentane, and/or methylcyclohexane.

The cyclohexanone reduction product in line 226 can be heated in one or more heat exchangers 114 to produce heated cyclohexanone reduction product via line 228 . The product of the reduction of cyclohexanone in line 226 can be used as a heat transfer medium to cool the dehydrated crude aniline entering first heat exchanger 114 to produce a first cooled dehydrated crude aniline via line 216 and a heated aniline via line 228. Hexanone reduction product. In another example, the product of cyclohexanone reduction in line 226 can be heated in a third heat exchanger (not shown). The third heat exchanger may be similar or identical to the second heat exchanger 118 described above. In another example, the product of cyclohexanone reduction in line 226 can be introduced directly to reactor 110 without first being heated in any heat exchanger.

The heated cyclohexanone reduction product via line 228 can be introduced into reactor 110 to produce a product containing a small amount of cyclohexanone via line 212 . The heated cyclohexanone reduction product can be reacted in reactor 110 to remove at least a portion of any cyclohexanone present. The amount of cyclohexanone removed from the cyclohexanone reduction product heated in reactor 110 can be as low as about 30%, about 40%, or about 50% to as high as about 60%, about 70%, about 80%, or about 90%. . The temperature of the product containing a small amount of cyclohexanone in line 212 can be as low as about 150°C, about 155°C, or about 160°C to as high as about 163°C, about 166°C, or about 170°C. The pressure of the product ranges from a low of about 101 kPa, about 120 kPa, or about 140 kPa to a high of about 160 kPa, about 180 kPa, or about 200 kPa.

The product via line 212 containing a small amount of cyclohexanone can have an aniline concentration ranging from a low of about 98 wt%, about 98.5 wt%, or about 99 wt% to a high of about 99.5 wt%, about 99.9 wt%, about 99.95 wt%, or about 99.99 wt%. wt%. The product containing a small amount of cyclohexanone via line 212 can have a concentration of water from as low as about 10 ppmw, about 50 ppmw, about 100 ppmw, about 500 ppmw, about 750 ppmw, or about 1,000 ppmw to as high as about 2,500 ppmw, about 3,500 ppmw, about 4,250 ppmw, Or about 5,000ppmw. The low cyclohexanone-containing product via line 212 can have a cyclohexanone concentration ranging from a low of about 1 ppmw, about 5 ppmw, about 10 ppmw, or about 20 ppmw to a high of about 40 ppmw, about 60 ppmw, about 80 ppmw, or about 100 ppmw. The product containing a small amount of cyclohexanone via line 212 can have a concentration of cyclohexylidene aniline as low as about 50 ppmw, about 100 ppmw, about 500 ppmw, about 750 ppmw, or about 1,000 ppmw up to about 2,500 ppmw, about 3,500 ppmw, about 4,250 ppmw, Or about 5,000ppmw. The product in line 212 containing a small amount of cyclohexanone can have a total concentration of other impurities ranging from a low of about 50 ppmw, about 100 ppmw, about 500 ppmw, about 750 ppmw, or about 1,000 ppmw to a high of about 2,500 ppmw, about 3,500 ppmw, about 4,250 ppmw, or about 5,000 ppmw, the other impurities may include, but are not limited to, benzene, toluene, phenol, mononitrobenzene, cyclohexanol, toluidine, cyclohexylamine, methylcyclopentane, and/or methylcyclohexane.

The product via line 212 containing minor amounts of cyclohexanone may be distilled or otherwise separated in separator 130 to produce a final or purified aniline product via line 234 and a waste or bulk by-product via line 232 . The purified aniline product in line 234 can have an aniline concentration ranging from a low of about 99 wt%, about 99.3 wt%, or about 99.5 wt% to a high of about 99.9 wt%, about 99.95 wt%, or about 99.99 wt%. The purified aniline product in line 234 can have an aniline concentration of at least 99 wt%, at least 99.4 wt%, or at least 99.5 wt% to about 99.9 wt% or about 99.95 wt%. The purified aniline product in line 234 can have a concentration of cyclohexanone from a low of about 1 ppmw, about 5 ppmw, about 10 ppmw, or about 20 ppmw to a high of about 40 ppmw, about 60 ppmw, about 80 ppmw, or about 100 ppmw. The purified aniline product in line 234 can have a water concentration of as low as about 10 ppmw, about 50 ppmw, about 100 ppmw, about 500 ppmw, about 750 ppmw, or about 1,000 ppmw to as high as about 2,500 ppmw, about 3,500 ppmw, about 4,250 ppmw, or about 5,000 ppmw . The purified aniline product in line 234 can have a cyclohexylideneaniline concentration ranging from a low of about 1 ppmw, about 5 ppmw, about 10 ppmw, or about 20 ppmw to a high of about 40 ppmw, about 60 ppmw, about 80 ppmw, or about 100 ppmw. The purified aniline product in line 234 can have a total concentration of other impurities ranging from a low of about 50 ppmw, about 100 ppmw, about 500 ppmw, about 750 ppmw, or about 1,000 ppmw to a high of about 2,500 ppmw, about 3,500 ppmw, about 4,250 ppmw, or about 5,000 ppmw, The other impurities may include, but are not limited to, benzene, toluene, phenol, cyclohexanol, cyclohexylamine, mononitrobenzene, toluidine, methylcyclopentane, and/or methylcyclohexane.

3 depicts a schematic diagram of another illustrative purification system 300 for producing purified aniline product 334 from crude aniline 102 , which does not include reactors upstream or downstream of cation exchange resin unit 322 . One or more lines 102 containing crude aniline may be connected to or in fluid communication with one or more dehydration units (one shown as 104) that dehydrate The units (one shown as 104) can separate at least a portion of any remaining water and/or other impurities contained therein to produce dehydrated crude aniline. The dehydrated crude aniline can be recovered via one or more lines 108 connected to or in fluid communication with the dehydration unit 104 and connected to the first heat exchanger 114 or connected to the first heat exchanger 114 is in fluid communication.

The dehydrated crude aniline in line 108 can have the same or similar composition as dehydrated crude aniline 108 described above with reference to FIGS. 1 and/or 2 . The first heat exchanger 114 can cool dehydrated crude aniline via line 108 to produce a first cooled dehydrated crude aniline, which can be recovered via one or more lines 316, the one One or more lines 316 connect or are in fluid communication with the first heat exchanger 114 and the second heat exchanger 118 . The second heat exchanger 118 may further cool the first cooled dehydrated crude aniline recovered from the first heat exchanger 114 via line 316 to produce a second cooled dehydrated crude aniline , the second cooled dehydrated crude aniline can be recovered via 320.

The second cooled dehydrated crude aniline via line 320 can be introduced to one or more cation exchange resin units 322 to produce a product containing a small amount of cyclohexanone via line 326 . The cation exchange resin unit 322 may include one or more cation exchange resins 324 . The cation exchange resin unit 322 and the cation exchange resin 324 may be the same as or similar to the cation exchange resin unit 122 and/or 222 and the cation exchange resin 124 and/or 224 described above with reference to FIGS. 1 and 2 , respectively. The minor cyclohexanone product in line 326 may have a composition similar to the composition of the minor cyclohexanone product in line 126 as described above with reference to FIG. 1 . In one example, the minor cyclohexanone product in line 326 can have the same composition as the minor cyclohexanone product in line 126 as described above with reference to FIG. 1 .

The product in line 326 containing a small amount of cyclohexanone can be used as a heat transfer medium to cool the dehydrated crude aniline, which is introduced into the first heat exchanger 114 via line 108 to produce the first cooled aniline via line 316. The dehydrated crude aniline and the heated product containing a small amount of cyclohexanone can be recovered via one or more lines 328 connected to one or more separators 130 or connected to one or more separators 130 fluid communication. The dehydration unit 104, first heat exchanger 114, second heat exchanger 118, cation exchange resin unit 322, and separator 130 may be as described above or elsewhere in this application.

The heated cyclohexanone-containing product via line 328 may be distilled or otherwise separated in separator 130 to produce a final or purified aniline product via line 334 and a waste or bulk by-product via line 332 . The purified aniline product via line 334 and waste via line 332 can be as described above and elsewhere in this application.

The purified aniline product in line 334 can have an aniline concentration ranging from a low of about 99 wt%, about 99.3 wt%, or about 99.5 wt% to a high of about 99.9 wt%, about 99.95 wt%, or about 99.99 wt%. The purified aniline product in line 334 can have an aniline concentration of at least 99 wt%, at least 99.4 wt%, or at least 99.5 wt% to about 99.9 wt%, or about 99.95 wt%. The purified aniline product in line 334 can have a concentration of cyclohexanone from a low of about 1 ppmw, about 5 ppmw, about 10 ppmw, or about 20 ppmw to a high of about 40 ppmw, about 60 ppmw, about 80 ppmw, or about 100 ppmw. The purified aniline product in line 334 can have a water concentration of as low as about 10 ppmw, about 50 ppmw, about 100 ppmw, about 500 ppmw, about 750 ppmw, or about 1,000 ppmw to as high as about 2,500 ppmw, about 3,500 ppmw, about 4,250 ppmw, or about 5,000 ppmw . The purified aniline product in line 334 can have a cyclohexylideneaniline concentration ranging from a low of about 1 ppmw, about 5 ppmw, about 10 ppmw, or about 20 ppmw to a high of about 40 ppmw, about 60 ppmw, about 80 ppmw, or about 100 ppmw. The purified aniline product in line 334 can have a total concentration of other impurities that can include, but are not limited to, Benzene, toluene, phenol, cyclohexanol, cyclohexylamine, mononitrobenzene, toluidine, methylcyclopentane, and/or methylcyclohexane.

4 depicts a schematic diagram of an illustrative system 400 for producing aniline and separating impurities therefrom. The system 400 may include one or more hydrogenation reactors 406 , one or more phase separators 410 , and one or more purification systems 416 . One or more purification systems 416 may be as described above with reference to FIGS. 1-3. For example, one or more purification systems 416 may be or include one or more of purification systems 100 , 200 , and/or 300 .

In operation, one or more aromatic nitro compounds via line 402 and hydrogen via line 404 can be introduced to a hydrogenation reactor 406 to produce a crude aniline product via line 408 . The composition of the crude aniline product in line 408 can depend, at least in part, on the particular aromatic nitro compound or combination of aromatic nitro compounds that are hydrogenated. Illustrative aromatic nitro compounds may include, but are not limited to, nitrobenzene, nitrotoluene, dinitrotoluene (DNT), dinitrobenzene (DNB), or any mixture thereof. The crude aniline product or reaction product in line 408 can include a mixture of aniline and one or more impurities prior to further purification or processing. Illustrative impurities may include, but are not limited to, water, phenol, nitrobenzene, benzene, nitrotoluene, dinitrotoluene (DNT), dinitrobenzene (DNB), polynitrobenzene, methylcyclopentane, Methylcyclohexane, mononitrotoluene, nitroxylene, cyclohexanone, cyclohexanol, cyclohexylamine, cyclohexanone, cyclohexylaniline, diphenylamine, phenylenediamine, cyclohexylideneaniline, toluidine , xylidine, toluene or any mixture thereof.

The reaction product via line 408 can be a gas, a liquid, or a mixture thereof. Water and/or aniline may also be introduced to hydrogenation reactor 406 (not shown). Water may be used as a quench fluid or medium, which may be used to regulate or otherwise adjust the temperature within hydrogenation reactor 406 . Aniline can be used as a carrier liquid for one or more catalysts. Thus, aniline may also include one or more of the catalysts therein. In another example (not shown), one or more catalysts can incorporate water and aniline. By-products or waste (not shown) may also be recovered from hydrogenation reactor 406 . By-products or wastes can be gases, liquids, or mixtures thereof. By-products may include water, used, spent, or spent catalyst, unreacted aromatic nitro compounds, phenol, impurities, aniline, or any mixture thereof.

The hydrogenation or reduction of aromatic nitro compounds in hydrogenation reactor 406 may be performed in a continuous, semi-continuous and/or batch manner. The hydrogenation of aniline can be carried out under liquid phase conditions and/or gas phase conditions. Hydrogenation can be carried out at temperatures ranging from as low as about 30°C, about 50°C, or about 80°C to as high as about 250°C, about 300°C, about 400°C, or about 500°C. Hydrogenation can be performed at pressures ranging from a low of about 101 kPa, about 150 kPa, or about 200 kPa to a high of about 1,000 kPa, about 2,000 kPa, about 3,500 kPa, or about 5,000 kPa. The reaction mixture of aromatic nitro compounds may have a residence time during hydrogenation of from about 1 minute to about three hours. The molar ratio of hydrogen to aromatic nitro compound can have a low of about 3:1, about 3.2:1, or about 3,4:1 to a high of about 3.8:1, about 4:1, or about 4.2:1.

The hydrogenation of aromatic nitro compounds can be carried out in the presence of one or more catalysts. Any suitable catalyst capable of promoting the hydrogenation of the aromatic nitro compound may be used. Illustrative catalysts may include, but are not limited to, nickel, iron, chromium, platinum, copper, cobalt, palladium, rhodium, iridium, their oxides, their hydroxides, their carbonates, their formates, or any mixture of them. Catalysts can be unsupported or supported. Illustrative support materials may include, but are not limited to, carbon, alumina, and the like. The catalyst concentration on the support can be as low as about 0.1 wt% to about 50 wt%, based on the weight of the support material. The particle size of the support material can be from about 0.01 μm to about 100 μm. The surface area of the support material may be from about 10 m ² to about 1,000 m ² per gram.

In addition to one or more catalysts, the hydrogenation of aromatic nitro compounds can also be carried out in the presence of water and/or aniline. Water and/or aniline can provide at least some control over the temperature of the hydrogenation reaction and/or can facilitate the introduction of the catalyst. For example, the catalyst can be introduced into a carrier liquid such as aniline and/or water to a hydrogenation reactor or zone. Spent, spent and/or spent catalyst may be recovered from the hydrogenation reactor or hydrogenation zone as a by-product or waste.

The aromatic nitro compound and the aniline/catalyst mixture can be introduced to the hydrogenation reactor 406 in the following weight ratios: about 1:0.45 to about 1:0.6, about 1:0.5 to about 1:0.6, about 1:0.5 to about 1:0.55, or about 1:0.45 to about 1:0.55. Aromatic nitro compounds and water may be introduced to hydrogenation reactor 406 in the following weight ratios: about 1:0.9 to about 1:1.25, about 1:1 to about 1:1.15, about 1:0.95 to about 1:1.1 , or about 1:1 to about 1:1.1. Aromatic nitro compounds and hydrogen may be introduced to hydrogenation reactor 406 in the following weight ratios: about 30:1 to about 10:1, about 25:1 to about 10:1, about 20:1 to about 10:1 , about 15:1 to about 10:1, or about 25:1 to about 12.5:1. The weight ratio of aromatic nitro compound and aniline/catalyst mixture can be about 1:0.5 to about 1:0.55, the weight ratio of aromatic nitro compound and water can be about 1:1 to about 1:1.1, and the aromatic nitro compound can be about 1:1.1. The weight ratio of the base compound to hydrogen may be from about 12.5:1 to about 25:1.

Illustrative methods for preparing aniline may include those described in US Patent Nos.: 8,809,587, 7,049,471, and 7,692,042 and US Patent Application Publication Nos.: 2007/0203364, 2007/0238901, and 2009/0065347.

Aniline can be prepared by reacting one or more phenols with an aminating agent. Illustrative phenols may include, but are not limited to, ortho, meta or para isomers of phenol, 2-methylphenol, 3-methylphenol, 4-methylphenol, ethylphenol and/or isopropylphenol, and Alkylphenols with at least one alkyl substituent, such as dimethylphenol, methylethylphenol, methylisopropylphenol, methylbutylphenol, diethylphenol, ethylbutylphenol, diisopropylphenol phenylphenol, isopropylbutylphenol, dibutylphenol or any mixture thereof. Illustrative aminating agents may include, but are not limited to, ammonia, ammonium carbonate, ammonium sulfate, ethylamine, n-propylamine, dimethylamine, diethylamine, diisopropylamine, methylethylamine, cyclohexylamine, aminopyridine , aniline, methylaniline, ethylaniline, n-propylaniline, isopropylaniline, dimethylaniline, diethylaniline, dipropylaniline, methylethylaniline, methylpropylaniline or any of them mixture. Illustrative methods of reacting one or more phenols with one or more aminating agents may include those described in US Patent No.: 5,545,753.

The reaction product via line 408 can have an aniline concentration of about 15 wt% to about 80 wt%. For example, the amount of aniline in the reaction product via line 408 can be as low as about 20 wt%, about 25 wt%, about 35 wt%, or about 45 wt% to as high as about 60 wt%, about 65 wt%, about 70 wt%, or about 75 wt%. The reaction product via line 408 can have a water concentration of about 25 wt% to about 85 wt%. For example, the amount of water in the reaction product via line 408 can be as low as about 25 wt%, about 40 wt%, about 45 wt%, or about 50 wt% to as high as about 60 wt%, about 65 wt%, about 70 wt%, or about 75 wt%. The reaction product via line 408 can include about 35 wt% to about 45 wt% aniline, about 55 wt% to about 65 wt% water, and less than about 5 wt% other components.

The reaction product via line 408 can be cooled to produce a cooled reaction product. For example, heat from the reaction product can be transferred indirectly to the heat transfer medium to produce a cooled reaction product as well as a heated heat transfer medium. Illustrative heat transfer media may include, but are not limited to, cooling water, boiler feed water, low pressure steam, medium pressure steam, glycol, air and/or other gaseous fluids, or any mixtures thereof. In another example, the reaction product can be cooled by direct contact or mixing with a cooling fluid, such as water, thereby producing a cooled reaction product. The reaction product via line 408 can be cooled by a combination of indirect heat exchange and direct contact cooling.

The temperature of the cooled reaction product via line 408 can be as low as about 0°C, about 25°C, about 50°C, or about 75°C to as high as about 150°C, about 175°C, or about 200°C. The pressure of the cooled reaction product via line 408 can be as low as about 101 kPa, about 300 kPa, or about 500 kPa to as high as about 1,000 kPa, about 1,500 kPa, or about 2,000 kPa.

The cooled reaction product via line 408 can be introduced to phase separator 410 to separate water from phase separator 410 via line 412 to produce crude or crude aniline via line 414 . Crude aniline 414 may be or include crude aniline via line 102 as described above with reference to FIGS. 1-3 and elsewhere in this application. Purified aniline product via line 420 and waste via line 418 can be obtained from one or more purification systems 416 . The purified aniline product via line 420 and the waste via line 418 can be as described above and elsewhere in this application. For example, the purified aniline product via line 420 may be the purified aniline product via lines 134, 234, and 334 or include the purified aniline product via lines 134, 234, and 334, and the waste via line 418 may be the waste via lines 132, 232, and 332 or include Waste via lines 132, 232 and 332. Additional details of aniline production and purification systems can be found in US Patent Publication No. 2012/0172627 or US Patent No. 8,809,587.

Example

To provide a better understanding of the above discussion, the following non-limiting examples are provided. All parts, ratios and percentages are by weight unless otherwise indicated.

Example 1

A set of tests was performed to determine the effect of the cationic resin on Reaction 2. Two classes of cationic resins were tested, namely type 13 (Ex. 1 ) and type 14 (Ex. 2) resins. Cationic resins were used wet, in the same shipping condition, without prior drying. The upper limit of the operating temperature for type 13 resins is about 120°C, and the upper limit for operating temperatures for type 14 resins is about 150°C. The aniline used in the tests was reagent grade aniline with a moisture content of less than 1,000 ppmw. About 50 mL of aniline was added to a separate glass flask and about 0.5 g of cationic resin was added to each flask. Heat the aniline/resin mixture to reaction temperature and stir on a shaker table. To each aniline/resin mixture, about 0.15 mL of reagent grade cyclohexanone was added to make an aniline solution containing about 3,000 ppmw cyclohexanone. Samples were taken at 15 minutes, 30 minutes and 60 minutes and analyzed for cyclohexanone content by gas chromatography. A control (CI) which did not contain any cation exchange resin was also tested. The test conditions and results are shown in Table 1 below.

Table 1

As shown in Table 1, when the aniline feed comprising cyclohexanone was contacted with the cation exchange resin at a temperature of about 110°C, the cyclohexanone concentration decreased significantly. For example, after 60 minutes, the concentration of cyclohexanone in Example 1 decreased by about 58%, and the concentration of cyclohexanone in Example 2 decreased by about 63%. In contrast, Control C1 contained about 2,995 ppmw cyclohexanone after 60 minutes.

Example 2

A second set of tests was performed by preparing a solution of cyclohexanone in aniline at an initial concentration of about 1,000 ppmw. About 50 mL of aniline and about 0.05 mL of cyclohexanone were mixed with each other. About 0.5 g of cation exchange resins (type 13 and type 14) were added to the aniline and cyclohexanone mixture. The test conditions and results are shown in Table 2 below.

Table 2

As shown in Table 2, when the aniline feed comprising cyclohexanone was contacted with the cation exchange resin at a temperature of about 110°C, the cyclohexanone concentration decreased significantly. For example, after about 60 minutes, the cyclohexanone concentrations of Examples 3 and 4 were reduced by about 52.5% and about 85.2%, respectively.

Example 3

A third set of tests was performed with a mixture of cyclohexanone in aniline prepared at an initial concentration of about 1,000 ppmw. About 50 mL of aniline and about 0.05 mL of cyclohexanone were mixed with each other. About 1 g of cation exchange resin (type 13 and type 14) was added to the aniline and cyclohexanone mixture. The test conditions and results are shown in Table 3 below.

table 3

As shown in Table 3, when the aniline feed comprising cyclohexanone was contacted with the cation exchange resin at a temperature of about 110°C, the cyclohexanone concentration decreased significantly. For example, after about 60 minutes, the concentrations of cyclohexanone for Examples 5 and 5 were reduced by about 52% and about 64%, respectively.

Example 4

The test was performed with a mixture of cyclohexanone in aniline at an initial concentration of about 1,000 ppmw. About 50 mL of aniline and about 0.05 mL of cyclohexanone were mixed with each other. About 0.5 g of cation exchange resin (type 14) was added to the aniline and cyclohexanone mixture. The test conditions and results are shown in Table 4 below.

Table 4

As shown in Table 4, when an aniline feed containing about 1,000 ppmw of cyclohexanone was contacted with a cation exchange resin at a temperature of about 140° C., the cyclohexanone concentration decreased by about 93.5%, and after 60 minutes, the cyclohexanone concentration was significantly reduce.

Example 5

The test was carried out with a mixture of cyclohexanone in aniline at a concentration of about 100 ppmw. About 50 mL of aniline and 0.005 mL of cyclohexanone were mixed with each other. About 0.5 g of cation exchange resin (type 14) was added to the aniline and cyclohexanone mixture. The test conditions and results are shown in Table 5 below.

table 5

As shown in Table 5, when a dry aniline feed containing 100 ppmw cyclohexanone was contacted with a cation exchange resin at a temperature of about 140°C, the concentration of cyclohexanone decreased by about 88%, and after 60 minutes, the concentration of cyclohexanone decreased significantly .

As shown in Tables 1-5, it has been surprisingly and unexpectedly found that contacting an aniline feed comprising cyclohexanone with a cation exchange resin at a temperature of about 110°C to about 140°C significantly reduces the aniline feed concentration of cyclohexanone in . The extent or amount of cyclohexanone reduction can depend, at least in part, on the contact time with the resin, the initial cyclohexanone concentration, resin type, temperature, and combinations of these adjustable variables.

Embodiments described herein further relate to any one or more of the following paragraphs:

1. A method for purifying crude aniline comprising contacting the crude aniline with a cation exchange resin to produce a product containing a small amount of cyclohexanone, said crude aniline comprising aniline, water and cyclohexanone, said containing a small amount of cyclohexanone The hexanone product contains less cyclohexanone than crude aniline, wherein the cation exchange resin is solid, semi-solid, or a combination thereof.

2. The process of paragraph 1, further comprising: hydrogenating nitrobenzene to produce crude aniline; separating at least a portion of the water from the crude aniline to produce dehydrated crude aniline; and contacting the dehydrated crude aniline with a cation exchange resin To prepare products containing a small amount of cyclohexanone.

3. The process of paragraph 2, further comprising: cooling the dehydrated crude aniline to produce cooled dehydrated crude aniline; contacting the cooled dehydrated crude aniline with a cation exchange resin to produce a product containing a small amount of cyclohexanone; The cyclohexanone product is introduced into a separation column to produce a purified aniline product.

4. The process of paragraph 3, wherein the crude aniline comprises about 85 wt% to about 99 wt% aniline, about 1 wt% to about 15 wt% water, and about 100 ppmw to about 15,000 ppmw cyclohexanone.

5. The process of paragraph 3 or 4, wherein the dehydrated crude aniline comprises from about 98 wt% to about 99.9 wt% aniline, less than 0.5 wt% water, and from about 100 ppmw to about 5,000 ppmw cyclohexanone.

6. The process of any of paragraphs 3 to 5, wherein the purified aniline product comprises from about 99 wt% to about 99.99 wt% aniline, less than 0.5 wt% water, and less than 100 ppmw cyclohexanone.

7. The process of any of paragraphs 3 to 6, wherein the dehydrated aniline is cooled in contact with the cation exchange resin for a period of 1 minute to about 15 minutes at a temperature of about 50°C to about 150°C, and contains a small amount of cyclohexanone The product contains at least 30% less cyclohexanone than crude aniline.

8. The process of any of paragraphs 3 to 6, wherein the dehydrated aniline is cooled in contact with the cation exchange resin at a temperature of about 50°C to about 150°C for a period of less than 60 minutes, and wherein the product containing a small amount of cyclohexanone comprises At least 50% less cyclohexanone compared to crude aniline.

9. The process of paragraph 1, wherein the crude aniline is contacted with the cation exchange resin for a period of 1 minute to about 15 minutes at a temperature of from about 50°C to about 150°C, and wherein the product containing a small amount of cyclohexanone comprises the mixture with the crude At least 30% less cyclohexanone compared to aniline.

10. The process of paragraph 1, wherein the crude aniline is contacted with the cation exchange resin for a period of 1 minute to about 15 minutes at a temperature of from about 50° C. to about 150° C., and wherein the product containing a small amount of cyclohexanone comprises the mixture with the crude At least 40% less cyclohexanone compared to aniline.

11. The process of paragraph 1, wherein the crude aniline is contacted with the cation exchange resin for a period of 1 minute to about 15 minutes at a temperature of from about 50°C to about 150°C, and wherein the product containing a small amount of cyclohexanone comprises the mixture with the crude At least 50% less cyclohexanone compared to aniline.

12. The process of paragraph 1, wherein the crude aniline is contacted with the cation exchange resin for a period of less than 60 minutes at a temperature of from about 50°C to about 150°C, and wherein the product containing a small amount of cyclohexanone comprises At least 50% less cyclohexanone.

13. The process of paragraph 1, wherein the crude aniline is contacted with the cation exchange resin for a period of less than 60 minutes at a temperature of from about 50°C to about 150°C, and wherein the product containing a small amount of cyclohexanone contains At least 60% less cyclohexanone.

14. The process of paragraph 1, wherein the crude aniline is contacted with the cation exchange resin for a period of less than 60 minutes at a temperature of from about 50°C to about 150°C, and wherein the product containing a small amount of cyclohexanone comprises At least 70% less cyclohexanone.

15. The method of any of paragraphs 1 to 14, wherein the cation exchange resin comprises H ⁺ functionality, sulfuric acid ^, _HSO4- functionality, or any combination thereof.

16. The method of any of paragraphs 1 to 15, wherein the cation exchange resin is in the form of pellets, beads, granules, flakes, spheres, cubes, blocks, fibers, filaments, threads, or any mixture thereof.

17. The process of any of paragraphs 1 to 16, wherein the cation exchange resin comprises a polymer based on a cross-linked styrene-divinylbenzene copolymer, said cross-linked styrene-divinylbenzene copolymer based polymer The polymer contains sulfuric acid and HSO ₄ ^-functional groups.

18. The method of any of paragraphs 1 to 17, wherein the cation exchange resin has an average pore size of about to about

19. The method of any of paragraphs 1 to 18, wherein the cation exchange resin has a pore volume of about 0.1 mL/g to about 1 mL/g.

20. The method of any of paragraphs 1 to 19, wherein the surface area of the cation exchange resin is from about 10 m ² /g to about 50 m ² /g.

21. The process of any of paragraphs 1 to 20, wherein at least a portion of the crude aniline is mixed with the cation exchange resin at a rate of about 0.1 ^m3 crude aniline per 1 ^m3 cation exchange resin per hour to about 30 ^m3 crude aniline per hour 1 m ³ of cation exchange resin was contacted per hour.

22. A method for purifying crude aniline comprising: hydrogenating aromatic nitro compounds to produce crude aniline comprising about 85 wt% to about 99 wt% of aniline, about 1 wt% to about 15 wt% of water and about 100 ppmw to About 15,000 ppmw cyclohexanone; at least a portion of the water is separated from the crude aniline to produce a dehydrated product comprising about 98 wt% or greater aniline, less than about 5,000 ppmw water, and about 100 ppmw to about 5,000 ppmw cyclohexanone ; reacting a portion of cyclohexanone in the dehydration product with a portion of aniline to prepare a cyclohexanone-reduced product comprising less cyclohexanone than the dehydration product; and at about 50° C. contacting the cyclohexanone-reduced product with a cation exchange resin to a temperature of about 150° C. to produce a cyclohexanone-containing product containing less cyclohexanone than the cyclohexanone-reduced product The cyclohexanone, wherein the cation exchange resin is solid, semi-solid, or a combination thereof.

23. The method of paragraph 22, wherein the cyclohexanone-reduced product is contacted with the cation exchange resin for a period of 1 minute to about 15 minutes, and wherein the cyclohexanone-containing product contains at least less than the cyclohexanone-reduced product 30% cyclohexanone.

24. The method of paragraph 22 or 23, wherein the cation exchange resin comprises H ⁺ functional groups, sulfuric acid, _HSO4- functional groups ^, or any combination thereof.

25. The method of any of paragraphs 22 to 24, wherein the cation exchange resin comprises a cross-linked styrene-divinylbenzene copolymer based polymer, said cross-linked styrene-divinylbenzene copolymer based polymer The polymer contains sulfuric acid, HSO ₄ ⁻ , functional groups.

26. The process of any of paragraphs 22 to 25, wherein a portion of the cyclohexanone is reacted with a portion of the aniline at a temperature of about 100°C to about 170°C.

27. The method of any of paragraphs 22 to 26, wherein the cation exchange resin has an average pore size of about to about

28. The method of any of paragraphs 22 to 27, wherein the cation exchange resin has a pore volume of about 0.1 mL/g to about 1 mL/g.

29. The method of any of paragraphs 22 to 28, wherein the surface area of the cation exchange resin is from about 10 m ² /g to about 50 m ² /g.

30. A system for purifying crude aniline, comprising: a hydrogenation reactor configured to hydrogenate aromatic nitro compounds to produce crude aniline comprising aniline, water, and cyclohexanone; and a cation exchange unit configured to react crude aniline with cations The exchange resin is contacted to produce a cyclohexanone-minor product comprising less cyclohexanone than crude aniline, wherein the cation exchange resin is a solid, a semi-solid, or a combination thereof.

31. The system of paragraph 30, further comprising a dehydration unit configured to separate water from the crude aniline to produce dehydrated crude aniline, the dehydrated crude aniline comprising less than the crude aniline Water, where the dehydration unit is located upstream of the cation exchange unit.

32. The system of paragraph 30 or 31, further comprising a reactor configured to react a portion of cyclohexanone in the dehydrated crude aniline to produce cyclohexanone-reduced crude aniline, wherein the reactor is located in a cation exchange unit upstream and downstream of the dehydration unit.

33. The system of any of paragraphs 30 to 32, further comprising a separator configured to separate at least a portion of any impurities from a product containing a small amount of cyclohexanone, thereby producing a purified aniline product.

Certain embodiments and features have been described using a set of numerical upper limits and a set of numerical lower limits. It should be understood that, unless otherwise indicated, the stated ranges are contemplated to include any combination of two values, such as any lower value in combination with any higher value, any two lower values in combination, and/or any two lower values. combination of high values. Certain lower limits, upper limits and ranges appear in one or more of the following claims. All numerical values are "about" equal to or "approximately" the stated value, and take into account experimental error and variations that would be expected by those skilled in the art.

Various terms have been defined above. To the extent a term used in a claim is not as defined above, it should be given the broadest definition given to those skilled in the art if the term is reflected in at least one printed publication or issued patent. Furthermore, all patents, test procedures, and other documents cited in this application are fully incorporated by reference to the extent that such disclosure is consistent with this application and in all jurisdictions in which such incorporation is permitted.

While the foregoing relates to embodiments of the invention, other and further embodiments of the invention can be devised without departing from its essential scope, which is defined by the following claims.

Claims (20)

1. the method for purification of crude aniline, is contacted to prepare containing a small amount of Ketohexamethylene with cation exchange resin including by crude aniline Product, described crude aniline comprises aniline, water and Ketohexamethylene, and the described product containing a small amount of Ketohexamethylene comprises than described rough benzene The few Ketohexamethylene of amine, wherein said cation exchange resin is solid, semi-solid or a combination thereof.

2. the method for claim 1, it further includes：

By nitrobenzene to prepare described crude aniline；

At least a portion of described water is separated from described crude aniline to prepare dehydration crude aniline；With

Described dehydration crude aniline is contacted with described cation exchange resin to prepare the described product containing a small amount of Ketohexamethylene.

3. the method for claim 2, it further includes：

Cooling described dehydration crude aniline is to prepare the dehydration crude aniline of cooling；

The dehydration crude aniline of described cooling is contacted with described cation exchange resin with prepare described containing a small amount of Ketohexamethylene Product；With

The described product containing a small amount of Ketohexamethylene is incorporated in knockout tower to prepare purification Aniline product.

4. the method for claim 3, wherein said crude aniline comprises about 85wt% to the aniline of about 99wt%, about 1wt% extremely The water of about 15wt%, and about 100ppmw is to the Ketohexamethylene of about 15,000ppmw, wherein said dehydration crude aniline comprises about The aniline of 98wt% to about 99.9wt%, less than the water of 0.5wt%, and about 100ppmw is to the Ketohexamethylene of about 5,000ppmw, and And wherein purification Aniline product comprises about 99wt% to the aniline of about 99.99wt%, less than the water of 0.5wt%, and is less than The Ketohexamethylene of 100ppmw.

5. the method for claim 1 wherein that described crude aniline is handed over by the temperature at about 50 DEG C to about 150 DEG C with described cation Change resin and contact time period of about 1 minute to about 15 minutes, and the wherein said product containing a small amount of Ketohexamethylene comprise with described Crude aniline compares the Ketohexamethylene at least lacking 30%.

6. the method for claim 1 wherein that described crude aniline is handed over by the temperature at about 50 DEG C to about 150 DEG C with described cation Change the time period that resin contact was less than 60 minutes, and the wherein said product containing a small amount of Ketohexamethylene comprises and described crude aniline Compare the Ketohexamethylene at least lacking 50%.

7. the method for claim 1 wherein that described cation exchange resin comprises H⁺Functional group, sulphuric acid, HSO₄ ^-Functional group or its Any combinations.

8. the method for claim 1 wherein described cation exchange resin form be pill, beadlet, granule, thin slice, spheroid, Cube, block, fiber, filamentous, threaded body or its any mixture.

9. the method for claim 1 wherein that described cation exchange resin comprises based on crosslinked styrene-divinylbenzene altogether The polymer of polymers, described comprises sulphuric acid and HSO based on crosslinked styrene diethylene benzene copoly mer₄ ^-Functional group.

10. the method for claim 1 wherein that the average pore size of described cation exchange resin is aboutTo aboutHole Volume be about 0.1mL/g to about 1mL/g, surface area is about 10m²/ g to about 50m²/g.

11. the method for claim 1 wherein at least a portion of described crude aniline with described cation exchange resin with speed Rate is about 0.1m³The every 1m of crude aniline³Cation exchange resin is per hour to about 30m³The every 1m of crude aniline³Cation exchange tree Fat is contacted per hour.

The method of 12. purification of crude aniline, including：Aromatic nitro compound is hydrogenated to prepare crude aniline, it comprises about 85wt% to the aniline of about 99wt%, the water of about 1wt% to about 15wt% and about 100ppmw to about 15,000ppmw hexamethylene Ketone；

At least a portion of described water is separated from described crude aniline to prepare dehydration product, it comprises about 98wt% or more Aniline, the less than about water of 5,000ppmw and about 100ppmw to about 5,000ppmw Ketohexamethylene；

A part for a part for Ketohexamethylene in described dehydration product and described aniline is reacted to prepare the product of Ketohexamethylene reduction Thing, the product of described Ketohexamethylene reduction comprises few Ketohexamethylene compared with described dehydration product；With

In about 50 DEG C to about 150 DEG C of temperature, the product that described Ketohexamethylene reduces is contacted with cation exchange resin and contained with preparing The product of a small amount of Ketohexamethylene, the described product containing a small amount of Ketohexamethylene comprises few hexamethylene compared with the product of described Ketohexamethylene reduction Ketone, wherein said cation exchange resin is solid, semi-solid or a combination thereof.

The method of 13. claim 12, the product of wherein said Ketohexamethylene reduction contacts about 1 point with described cation exchange resin The Zhong Zhiyue time period of 15 minutes, and the wherein said product containing a small amount of Ketohexamethylene comprises the product with the reduction of described Ketohexamethylene Compare the Ketohexamethylene at least lacking 30%.

The method of 14. claim 13, wherein said cation exchange resin comprises H⁺Functional group, sulphuric acid, HSO₄ ^-Functional group or Its any combinations.

15. the method for claim 12, wherein said cation exchange resin comprises based on crosslinked styrene-divinylbenzene The polymer of copolymer, described comprises sulphuric acid, HSO based on crosslinked styrene diethylene benzene copoly mer₄ ^-, functional group.

The method of 16. claim 12, wherein about 100 DEG C to about 170 DEG C temperature by with the partial reaction of described aniline The part of described Ketohexamethylene is reacted.

The system of 17. purification of crude aniline, including：

Hydrogenation reactor, it is configured to make aromatic nitro compound hydrogenation comprise the rough of aniline, water and Ketohexamethylene to prepare Aniline；With

Cation exchange unit, it is configured to make crude aniline contact with cation exchange resin to prepare containing a small amount of Ketohexamethylene Product, the described product containing a small amount of Ketohexamethylene comprises the Ketohexamethylene fewer than described crude aniline, wherein said cation exchange tree Fat is solid, semi-solid or a combination thereof.

The system of 18. claim 17, it comprises dewatering unit further, and described dewatering unit is configured to water from described rough Aniline separates to prepare dehydration crude aniline, and described dehydration crude aniline comprises the water fewer than described crude aniline, wherein said Dewatering unit is located at the upstream of described cation exchange unit.

19. the system of claim 18, it comprises reactor further, and described reactor configurations are to make described dehydration crude aniline To prepare the crude aniline of Ketohexamethylene reduction, wherein said reactor is located at described cation and hands over for the part reaction of middle Ketohexamethylene Change the upstream of unit and the downstream of described dewatering unit.

The system of 20. claim 19, it comprises separator further, and described separator is configured to make at least the one of any impurity Part separates from the described product containing a small amount of Ketohexamethylene to prepare the Aniline product of purification.