DE102005046815A1 - Shaped article containing aluminosilicate and alumina with polymodal pore distribution, useful as catalyst for preparation of methylamines from ammonia and methanol or dimethyl ether - Google Patents

Abstract

Shaped body containing an aluminosilicate and aluminum oxide, the shaped body having a molar Al / Si ratio in the range from 10 to 30 and an at least bimodal pore distribution for pores with a diameter of greater than 1 nm, the volume of the pores of the shaped body having a diameter of greater than 10 nm corresponds to at least 40% of the total pore volume of the molded body, DOLLAR A process for its production and DOLLAR A process for the continuous production of methylamines by reacting methanol and / or dimethyl ether with ammonia in the presence of a heterogeneous catalyst, the catalyst being the above Shaped body is used.

Description

The The present invention relates to a molded article containing an aluminosilicate and alumina, a process for its preparation and a process for the continuous production of methylamines by reaction of methanol and / or dimethyl ether with ammonia.

Monomethylamine (MMA) is an intermediate used in the synthesis of pharmaceuticals (e.g. Theophylline), pesticides (carbaryl, metham sodium, carbofuran), Surfactants, photographic developers, explosives and solvents such as N-methyl-2-pyrrolidone (NMP) is used.

dimethylamine (DMA) is also a synthetic intermediate. Examples for products Dimethylamine-based fungicides and vulcanization accelerators (Zinc bis-dimethyldithiocarbamate) (Ziram), tetramethylthioperoxydicarbonic acid diamide (TMTD), Tetramethyl thiocarbonic acid (MTMT), the blowing agent 1,1-dimethylhydrazine, various pharmaceuticals, monomers such as e.g. dimethylaminoethyl solvent (N, N-dimethylformamide, N, N-dimethylacetamide), catalysts [e.g. 2,4,6-bis [(dimethylamino) methyl] phenol (DMP 30)], the insecticide Dimefax, surfactants and ion exchange resins.

trimethylamine (TMA) is used in the production of choline salts, cationic starches, disinfectants, Flotation agents, sweeteners and ion exchange resins used.

The Synthesis of monomethylamine (MMA), dimethylamine (DMA) and trimethylamine (TMA) is carried out from ammonia and methanol in the gas phase, e.g. at amorphous alumina, or silica-alumina (mixed forms of aluminum and silica) at pressures from 10 to 50 bar. When using higher temperatures (350 to 475 ° C) the thermodynamic equilibrium of these heterogeneous catalysts one or is approximately reached, when the residence time in the reactor given pressure and given inlet temperature is sufficient (see: Catalysis Today, 1997, 37, pages 71-102).

For the alkylation of ammonia, monomethylamine (MMA) and / or dimethylamine (DMA) with methanol (= amination reaction), the reaction rate in the series NH ₃ >MMA> DMA increases. Accordingly, the proportion of TMA on the amorphous "equilibrium catalysts" in the straight pass, based on the sum of MMA, DMA and TMA, is between 35 and 75 percent by weight The product distribution is dependent on the temperature and the N / C ratio (see : Ind. Eng. Chem. Res. 2004, 43, pages 5123-5132).

Of the worldwide consumption of trimethylamine is based on the total amount the methylamine at less than 20 weight percent (see: Ullmann's Encyclopedia of Industrial Chemistry, 5th Edition, A16, pages 535-541). It is therefore necessary to increase the proportion of DMA and MMA in the reaction mixture.

This is achieved by recycling of TMA and ammonia on the catalyst, in which case the TMA is converted in a mixture of MMA, DMA and TMA (= transalkylation reaction). The process for producing methylamines from methanol and ammonia combining the amination and transalkylation reaction is called the Leonard process (see: US 3,387,032 , "Alkylamines" PEP Report No. 138, 1981, (SRI International, Menlo Park, California) and Hydrocarbon Process 1979, 58, pages 194ff.) Through recycle, the product mix can be adjusted as needed, a typical example is a mixture consisting of 34% by weight MMA, 46% by weight DMA and 20% by weight TMA ("Alkylamines" PEP Report No. 138, 1981).

In US 1,875,747 (Martin et al.) Describes the preparation of methylamines from NH ₃ and MeOH on aluminosilicate catalysts at temperatures between 300 and 500 ° C. The aluminosilicate can be used as a synthetic solid or in the form of alumina.

In EP-A-64 380 (DuPont) describes a catalyst which is characterized by the treatment of an aluminosilicate with the hydroxide salts of sodium, potassium, Lithium, barium or strontium is obtained, the proportion Na, K, Li, Ba or Sr is between 0.1 and 6 wt .-%. The usage of the catalyst for the production of methylamines from methanol and ammonia, wherein the proportion of monomethylamine (MMA) by an increase in the alkali or Erdalkalianteils can be adjusted is also mentioned.

DD-A-266 096 (VEB Leuna) describes a process for the preparation of methylamines on a SiO ₂ -Al ₂ O ₃ dehydration catalyst, wherein an Al ₂ O ₃ or Al ₂ O ₃ / SiO _{2 support} in a fluidized bed is sprayed with a nitric acid-containing suspension of finely ground boehmite and kaolin in water and the spherical catalyst after thermal activation at 400 to 600 ° C a bulk density of 0.5 to 0.6 kg / l, an Al ₂ O ₃ content of 70 to 80% and a pore volume of 0.75 to 0.85 ml / g, wherein the pore volume in the region of the pores with diameter below 15 nm at least 0.3 ml / g and in the region of the pores with diameter above 15 nm at least 0.4 ml / g and of which in turn must have at least 0.2 ml / g in the area of the pores with a diameter above 100 nm. The catalysts of the invention allegedly have a 20% longer life and have after expansion less coke deposits and destroyed moldings. The proportion of Al ₂ O ₃ between 70 and 80% corresponds to a molar Al / Si ratio between 2.7 and 4.7.

DD-A-149 213 (VEB Leuna) discloses a process for the preparation of methylamines on dehydrating catalysts containing active alumina using a kaolin-pseudo-boehmite-based catalyst containing, in addition to alumina 12-18 Wt .-% of silica whose total pore volume is greater than 0.5 ml / g, wherein the proportion of pores having a diameter smaller than 4 nm is at least 30% and greater than 15 nm at most 10% and its grain size or wall thickness smaller 4 mm. According to the data, the catalyst could be run for 13 months without significant deactivation [U (MeOH)>99%]; the deposit on the expansion catalyst contained about 1.2% by weight of carbon. The proportion of SiO ₂ between 12 and 18% corresponds to a molar Al / Si ratio between 5.4 and 8.6.

In EP-A-62 428 (= US 4,370,503 ) describes the use of a catalyst consisting of 88 to 99% by weight of alumina and 1 to 13% by weight of silica for the preparation of methylamines from methanol or dimethyl ether and ammonia. The weight distributions of silica and alumina correspond to a molar Al / Si ratio of 7.9 to 116.7. The catalyst is usually present as a tablet with a diameter and / or length of 3 to 13 mm. The pore volume of the tray is between 0.2 and 0.8 ml / g, the BET surface area between 100 and 250 m ² / g.

DD-A-108 275 (Becker et al.) Describes a process for the preparation of methylamines on fixed catalysts consisting of alumina and / or aluminosilicates, the catalyst being used in the form of a hollow strand whose total diameter is 3 to 10 mm and whose cavity diameter is 1 to 5 mm, a total pore volume of at least 30% pores having a diameter greater than 100 Å, a surface area of at least 130 m ² / g and an acidity of at most 2.0 × 10 ^-5 mol NH ₃ / g has. In comparison to the solid strand, a 41% lower pressure loss was allegedly measured when using the hollow strand, fewer minor components were formed, the deposition of low-hydrogen compounds could be reduced and the service life of the catalyst increased by 30%.

SU-A1-1766 499 (Chem. Abstr 120: 57149) describes the preparation of a silica-alumina catalyst. The improvement over the prior art is the use of Al (OH) ₃ instead of pseudo-boehmite, reduction of the kaolin to aluminum hydroxide ratio from 50 to 10 wt .-%, addition of Rückgemalenem in the catalyst preparation and peptization of the mixture before extrusion with ENT ₃ followed by treatment with an ammoniacal solution.

By the measures can supposedly be the activity increased and improved the mechanical properties of the moldings become.

In SU-A1-1766500 (Chem. Abstr. 120: 57148) is based on SU-A1-1766 499, the advantageous use of formic acid instead of nitric acid Peptization of the extrusion mass described.

DE-A-1 543 731 (Leonard) teaches a process for the preparation of amines by reacting ammonia with alcohols, ethers and mixtures thereof in the vapor phase and in the presence of catalysts, wherein the catalyst consists of a silica gel base to which active Alumina and traces of metal salt mediators are applied and the catalyst is partially deactivated before use by a treatment with water vapor of 1-50 atmospheres. The catalyst usually contains between 12 and 13 wt .-% Al ₂ O ₃ . The steam treatment reduces the total surface area of the catalyst to 90 ± 20 m ² / g and sets the pore volume to 0.34 ± 0.10 ml / g and the pore diameter to 74 ± 10 Å. The deactivation of the aluminosilicate and the application of silver, rhenium, molybdenum and cobalt salts allegedly increased the proportion of DMA in the reaction mixture from 32 to 35% by weight to> 50% by weight.

To Information of the o.g. 1981 PEP reports on the production of alkylamines, especially methylamines, reported, the lifetime of an aluminosilicate catalyst about 1.5 years. ("Alkylamines", M. Arné, Process Economics Program Report No. 138, 1981, California, USA, pages 19-41).

The Service life of the described aluminosilicate catalysts of the state The technology is a maximum of 2 years.

The German patent application no. 102004062718.5 dated 21.12.04 (BASF AG) relates to a process for the preparation of methylamines from methanol in the presence of an acidic, shape-selective molecular sieve and in Presence of hydrogen.

For the development of a catalyst for the methylamine process, it is desirable that the catalyst is active for both the amination and transalkylation reactions under the given reaction conditions.

Both Reactions are acid catalysed, so that the acidity of the catalyst, which by the density and strength the Brönsted and / or Lewis acid centers is of crucial importance (See: Ind. Eng. Chem. Res. 2004, 43, pages 5123-5132). The acidity According to the invention, the catalyst should be optimized so that activation of the starting materials by complex formation with the active center possible However, the complexes are not so stable that Coke and / or Coke precursors form or deactivate the activity centers. A possibility the acidity of the catalyst is the adjustment of the molar Al / Si ratio.

is the acidity set the catalyst, according to the invention, the residence time the educts and products in the catalyst bodies are optimized so that is sufficient under the given reaction conditions Diffusion of the educts and products from and to the active centers as well as of the Reaction medium in and out of the pores of the catalyst is possible. Since the silica-alumina catalysts are generally not microporous, optimizing the porosity of the catalyst means optimization the macro (pore diameter> 25 nm) and / or mesopores (pore diameter 1-25 nm).

to Use of the catalyst on a production scale should be the shape of the molded article should be so chosen be that the pressure drop in the reactor is as low as possible. In addition, should the moldings be mechanically stable under the given reaction conditions, that filling heights of up to 40 m possible are minimized and the formation of abrasion during the reaction becomes.

Of the The present invention was therefore based on the object, an improved Catalyst and an improved economical process for Production of methylamines find. In particular, that should Process with high methanol conversion (e.g.,> 95%) a catalyst lifetime of more than 2 years guarantee.

Accordingly, became a shaped body containing an aluminosilicate and alumina, which characterized in that the shaped body has a molar Al / Si ratio in the Range from 10 to 30 and for Pores with a diameter greater than 1 nm an at least bimodal Having pore distribution, wherein the volume of the pores of the shaped body with a diameter greater than 10 nm at least 40% of the total pore volume of the molding corresponds.

The Pore volumes are determined by Hg porosimetry according to DIN 66134.

• (I) Herstellen eines Gemischs, enthaltend das Alumosilikat, das Aluminiumoxid als Bindemittel, ein Anteigmittel und ein Lösungsmittel,
• (II) Vermischen und Verdichten des Gemischs,
• (III) Verformen des verdichteten Gemischs unter Erhalt eines Formkörpers,
• (IV) Trocknen des Formkörpers und
• (V) Calcinieren des getrockneten Formkörpers

umfasst,
und ein Verfahren zur kontinuierlichen Herstellung von Methylaminen durch Umsetzung von Methanol und/oder Dimethylether mit Ammoniak in Gegenwart eines Heterogen-Katalysators gefunden, welches dadurch gekennzeichnet ist, dass als Katalysator der o.g. Formkörper eingesetzt wird.Furthermore, a process for the preparation of the abovementioned shaped body was found, which is characterized in that it comprises the steps

• (I) preparing a mixture containing the aluminosilicate, the alumina as a binder, a pasting agent and a solvent,
• (II) mixing and compressing the mixture,
• (III) deforming the compacted mixture to obtain a molded article,
• (IV) drying of the molding and
• (V) calcining the dried shaped article

includes,
and a process for the continuous production of methylamines by reacting methanol and / or dimethyl ether with ammonia found in the presence of a heterogeneous catalyst, which is characterized in that the above-mentioned shaped body is used as the catalyst.

in the inventive method is the service life of the catalyst according to the invention more than 3 years, especially more than 4 years, and is e.g. in the period from 3 to 6 years.

To Production and properties of the molding according to the invention, in the process according to the invention used as catalyst:

The aluminosilicate (step I)

When Aluminosilicate are preferably clays, and more preferably phyllosilicates from the kaolin group (see: Ullman's Encyclopedia of Industrial Chemistry, 6th edition, 2000 electronic edition, chapter 2 and textbook of the Inorganic Chemistry, 91.-100. Edition, 1985, pp. 771-776). All Particular preference is given to using kaolinite.

The Kaolinite is an essential component of kaolin, which u. a. in deposits in Georgia, England, the United States, Brazil, Germany, Czech Republic, Spain, Russia and Australia (see: Ullman's Encylopedia of Industrial Chemistry, 6th edition, 2000 electronic edition, chapter 3.1). The natural kaolin contains in addition to kaolinite small amounts of feldspar, mica and quartz and can be purified by methods known in the art, here it's about Ullman's Encyclopedia of Industrial Chemistry, 6th edition, 2000 electronic Edition, chapter 4.1. mentioned "dry process" and "wet process" method.

Synthetically, kaolinite can be hydrothermal malsynthese be obtained from polysilicic acid and aluminum hydroxide at pH <7.

Of the Clay, preferably kaolin, and more preferably kaolinite, contains preferably traces of titanium, iron, sodium and potassium. The proportion of this Elements is preferred for Titanium between 0.1 and 1.0% by weight, for iron between 0.1 and 1.0% by weight, for potassium between 0.1 and 5.0 wt .-% and for sodium between 0.1 and 5.0% by weight.

Of the Proportion of clay, preferably kaolin and particularly preferably kaolinite, in the finished catalyst strand is between 1 and 30 wt .-%, preferably between 2 and 20 wt .-% and particularly preferably between 5 and 15 wt .-%.

The alumina binder (Step I)

The binders used are oxides of aluminum and particularly preferably γ-Al ₂ O ₃ .

As a precursor to the alumina, aluminum hydroxide and / or alumina / hydroxide is added to the mixture in step I. As the aluminum hydroxide, both the synthetic Al (OH) ₃ or the natural hydrargillite [γ-Al (OH) ₃ ] can be used. As alumina / hydroxide [γ-Al (O) OH], boehmite and / or pseudoboehmite are preferably used.

In a particular embodiment, a mixture of aluminum hydroxide and / or aluminum oxide / hydroxide and γ-Al ₃ O _{3 is used} as a precursor.

In the calcining step according to V, at least 80% of the aluminum hydroxide and / or aluminum oxide / hydroxide used is converted into γ-Al ₂ O ₃ .

Of the Proportion of binder in the final molded article, e.g. Strand, is at least 50% by weight and is preferably between 50 and 99% by weight, especially preferably between 75 and 95 wt .-%.

The solvent (step I)

When Solvent, that is also a diluent can be, water is used.

the Water can both Bronsted acids also Brönsted bases be added.

suitable Bronsted acids are for example, hydrochloric acid, Sulfuric acid, Phosphoric acid, nitric acid or Carboxylic acids, Dicarboxylic acids or Oligo- or polycarboxylic acids, such as nitrilotriacetic acid, sulfosalicylic acid or ethylenediaminetetraacetic acid.

Prefers is called Brönsted acid formic acid or nitric acid used.

suitable Bronsted bases are primary, secondary and tertiary Alkylamines, ammonia, and rare earth, alkali and alkaline earth metal hydroxides.

Prefers is called Brönsted base Ammonia used.

Of the Proportion of Bronsted acids and / or Bronsted bases in the solvent (e.g., water) is especially between 0.5 and 99% by weight, preferably between 1 and 50 wt .-%, more preferably between 5 and 25 wt .-%.

The Addition of the solvent causes the mixture to have the right consistency for further processing in the molding step. The proportion of solvent is preferred in the range of 0.5 to 80 wt .-%, more preferably in the range of 0.8 up to 50% by weight, more preferably in the range from 1 to 40% by weight, and more preferably in the range of 1 to 30% by weight, respectively based on the total mass of the mixture according to step I.

In a particular embodiment, the mixture is first treated with a solution of a Bronsted acid (eg, formic acid) and then with a solution of a Bronsted base (eg, NH ₃ ).

The pasting agent (step I)

at the preparation of the mixture according to (I) is at least one Anteigmittel (= organic additive) added.

When Anteigmittel (= pasting) can all be suitable Connections are used. Preferably, these are organic, especially hydrophilic polymers such as cellulose, cellulose derivatives, such as methylcellulose, starch, such as potato starch, polyacrylates, Polymethacrylates, polyvinyl alcohol, polyvinylpyrrolidone (PVP), polyisobutene (PIB) or polytetrahydrofuran (PTHF).

Especially can as a pasting agent compounds are used, which are also called pore formers Act.

The Anteigmittel is in a particularly preferred embodiment of the method according to the invention, as described below, in step V by calcining at least 90% by weight removed.

The addition of the mordanting agent causes the mixture to have the right consistency for the next processing in the forming step has. The proportion of pasting agent is preferably in the range of 0.5 to 80 wt .-%, more preferably in the range of 1 to 50 wt .-%, more preferably in the range of 2 to 40 wt .-%, and particularly preferably in the range from 3 to 30 wt .-%, each based on the total mass of the mixture according to step I.

Pore former (optional, Step I)

The Mixture of binder, aluminosilicate, pasting agent and solvent according to I can for further processing and for forming a plastic mass be offset with at least one other compound. Under Other preferred are pore-forming agents.

When Pore formers can in the process according to the invention all Compounds are used, with respect to the finished molding a specific Pore size, one certain pore size distribution and / or provides certain pore volumes.

Prefers are used as pore formers in the process according to the invention polymers, in water or in water Solvent mixtures dispersible, suspendable and / or emulsifiable. Preferred polymers here are polymeric vinyl compounds such as polyalkylene oxides, such as polyethylene oxides, polystyrene, polyacrylates, polymethacrylates, Polyolefins, polyamides and polyesters, carbohydrates, such as cellulose or cellulose derivatives, such as methylcellulose, or sugars or natural fibers. Other suitable pore formers are pulp or Graphite.

Also preferred are organic acidic compounds which can be removed by calcining in step V as described below. These include carboxylic acids, in particular C _1-8 carboxylic acids, such as formic acid, oxalic acid and / or citric acid. It is also possible to use two or more of these acidic compounds.

Become used in the preparation of the mixture according to step I pore formers, Thus, the content of the mixture according to (I) is preferred to pore-forming agents in the range of 0.5 to 80 wt .-%, most preferably in the range of 1 to 50 wt .-% and particularly preferably in the range of 2 to 30 % By weight, in each case based on the amount of aluminosilicate in the mixture according to (I).

Should this for the pore size distribution to be achieved he wishes be, a mixture of two or more pore-forming agents can be used.

The Pore formers are in a particularly preferred embodiment of the method according to the invention, as described below, in step V by calcining below Preservation of the porous molding to at least 90% by weight removed.

Mixing and compacting (Step II)

To in the preparation of the mixture according to (I), the mixture is homogenized, e.g. For a duration in the range of 10 to 180 minutes. Especially preferred are used for homogenization, inter alia, kneader, Koller or extruder used. On a smaller scale the mixture is preferably kneaded. In industrial, larger scale becomes For homogenization preferably gekollert.

at Homogenization is preferred at temperatures in the range of approximately 10 ° C to to the boiling point of the solvent and normal pressure or slightly superatmospheric Pressure worked. Thereafter, if appropriate, at least one of be added as described above. The thus obtained Mixture is homogenized, preferably kneaded until a verstrangbare plastic mass is formed.

The homogenized mixture is deformed in a subsequent step.

Deform of the compressed mixture to obtain a shaped article (step III) To carry out In this step, those methods are preferred in which the deformation by extrusion in conventional extruders, for example, strands with a diameter of preferably 1 to 10 mm, and more preferably 2 to 5 mm, takes place. Such extrusion devices become, for example in Ullmann's Encyclopedia of Technical Chemistry, 4th Edition, Vol. 2, p. 295 et seq., 1972.

Next The use of an extruder is also preferably a Extruder used for deformation.

• (i) Brikettieren, d.h. mechanisches Verpressen mit oder ohne Zusatz von zusätzlichem Bindermaterial;
• (ii) Pelletieren, d.h. Kompaktieren durch kreisförmige und/oder rotierende Bewegungen;
• (iii) Sintern, d.h. das zu verformende Materials wird einer thermischen Behandlung ausgesetzt.

In principle, however, all known and / or suitable kneading and shaping devices or methods can be used for shaping. Among others, these include:

• (i) briquetting, ie mechanical pressing with or without the addition of additional binder material;
• (ii) pelleting, ie compacting by circular and / or rotary motions;
• (iii) sintering, ie the material to be deformed is subjected to a thermal treatment.

For example, the shaping may be selected from the following group, wherein the combination of at least two of these methods explicitly included: briquetting by stamp presses, roll presses, ring roll presses, briquetting without binder; Pelletizing, melting, spinning techniques, deposition, foaming, spray-drying; Burning in the shaft furnace, convection oven, traveling grate, rotary kiln, rumbling.

The Compaction may be at ambient pressure or at opposite Ambient pressure increased Pressure take place, for example in a pressure range of 1 bar up to several hundred bar. Furthermore, the compaction at Ambient temperature or at relative to the ambient temperature increased Temperature take place, for example in a temperature range from 20 to 300 ° C. is Drying and / or firing part of the shaping step, so are temperatures up to 1500 ° C conceivable. After all The compaction may take place in the ambient atmosphere or in one controlled atmosphere. Controlled atmospheres For example, inert gas atmospheres, reducing and / or oxidizing atmospheres.

The Shape of the molded body produced according to the invention can chosen arbitrarily become. In particular, among other things, balls, oval shapes, cylinders or tablets possible.

Especially In the context of the present invention, deformation is preferred by extrusion of the according to step II mixture obtained, wherein as extrudates more preferably substantially cylindrical strands with a diameter in the range of 0.5 to 20 mm, preferably in the range be obtained from 1 to 10 mm.

at the extrudates the length : Diameter - ratio in particular at least 1, preferably in the range of greater than 1 to 20, particularly preferably in the range of 2 to 10.

Drying of the molding (step IV)

the Step (III) closes in the context of the present invention preferably at least one drying step at. This at least one drying step takes place at temperatures in the range of preferably 80 to 160 ° C, especially 90 to 145 ° C and especially preferably from 100 to 130 ° C, wherein the drying time is preferably 6 hours or more, for example in the range of 6 to 24 h. However, they are dependent from the moisture content of the material to be dried also shorter drying times such as about 1, 2, 3, 4, or 5 h possible.

In front and / or after the drying step, the preferably obtained Extrudate be crushed, for example. It is preferred a granule or grit having a particle size in the range of 0.1 to 5 mm, in particular 0.5 to 2 mm.

Calcination of the molding (step V)

the Step (IV) is followed by at least one calcination step. The calcination is at temperatures in the range of preferably 350 to 750 ° C and in particular from 450 to 700 ° C carried out.

The Calcination can take place under any suitable gas atmosphere, wherein air and / or lean air are preferred.

The Calcining according to (V) can also in the presence of hydrogen, nitrogen, helium, argon and / or Steam or mixtures thereof take place.

Further the calcination is preferably in a muffle furnace, a rotary kiln and / or a belt calcination oven, wherein the calcination time preferably at 1 h or more, for example in the range from 1 to 24 h or in the range of 3 to 12 h. Accordingly, it is in the context of the method according to the invention for example, possible the shaped body once, twice or more often for each at least 1 h, such as in each case in the range of 3 to 12 h, the temperatures being equal during a calcination step remain or be changed continuously or discontinuously can. Will be twice or more often calcined, can the calcination temperatures differ in the individual steps or be the same.

To For example, in the calcination step, the calcined material be crushed. In this case, preferably a granule or grit with a particle size in the range from 0.1 to 5 mm, in particular 0.5 to 2 mm.

The obtained molded body show hardships, which is preferably in the range of 2 to 200 N (Newton), more preferably in the range of 5 to 150 N, and most preferably at least 10N, e.g. ranging from 10 to 100N.

The above-described hardness was in the context of the present invention on a Zwick, type BZ2.5 / TS1S with a pre-load of 0.5 N, a Vorkraftschubgeschwindigkeit of 10 mm / min. and a subsequent test speed of 1.6 mm / min. certainly. The device had a fixed turntable and a freely movable punch with built-in cutting edge of 0.3 mm thickness. The movable punch with the cutting edge was connected to a load cell for power absorption and moved during the measurement against the fixed turntable on which the catalyst molding to be examined was located. The tester was controlled by a computer, which registered and evaluated the measurement results. The values obtained represent the average of the measurements for at least 10 shaped catalyst bodies.

Of the obtained moldings preferably has a molar Al / Si ratio in the range of 11 to 25, in particular in the range of 12 to 23, on.

The Details of the molar Al / Si ratio in moldings refer to the total content of Al and Si.

The specific surface area of the resulting molded article, determined according to DIN 66131 (BET), is preferably at least 50 m ² / g and particularly preferably at least 100 m ² / g. For example, the specific surface area is in the range of 50 to 250 m ² / g, and more preferably in the range of 100 to 200 m ² / g.

The Pore volume of the resulting molded article, determined in accordance with DIN 66134 (Hg porosimetry) preferably at least 0.4 ml / g, more preferably at least 0.6 ml / g. For example, the pore volume is in the range of 0.4 to 1.5 ml / g and in particular in the range of 0.6 to 1.0 ml / g.

The Pores of the resulting molded article with a diameter> 1 nm determined according to DIN 66134 (Hg porosimetry), have a multimodal, at least bimodal distribution, prefers a bimodal distribution, the proportion of pores with a diameter> 10 nm at least 40%, preferably at least 50%, of the total pore volume occupies and e.g. in the range of 40 to 60%.

Of the moldings contains preferably traces of titanium, iron, sodium and potassium. The amount of these elements is preferably between 0.01 and 0.35 for titanium % By weight, for Iron between 0.01 and 0.35 wt .-%, for potassium between 0.01 and 1.75 wt .-% and for Sodium between 0.01 and 1.75 wt .-%, each based on the molding weight.

Preparation of methylamines on the catalyst according to the invention:

The Preparation of methylamines on the catalyst according to the invention takes place by reaction of ammonia and methanol and / or dimethyl ether in the gas phase at elevated Pressure and elevated Temperature. Optionally, the reaction mixture may include water, monomethylamine, Dimethylamine and / or trimethylamine are added or included.

The catalyst loading, expressed in kilograms of methanol per kilogram of catalyst per hour, is preferably in the range of 0.1 to 2.0 h ^-1 , in particular in the range of 0.2 to 1.5 h ^-1 , very particularly in the range of 0 , 4 to 1.0 h ^-1 .

The molar N / C ratio based on the sum of the starting materials is preferably in the range of 0.6 to 4.0, especially 0.8 to 2.5, especially 1.0 to 2.0.

The Reaction is preferred at a temperature in the range of 250 up to 500 ° C, especially 300 to 475 ° C, especially 350 to 450 ° C, performed.

Of the Absolute pressure of the reaction is preferably in the range of 5 to 50 bar, especially 10 to 30 bar, in particular 15 to 25 bar.

Of the Methanol conversion is preferably> 85%, more preferably between 90 % and 99%, especially between 95% and 99%.

The selectivity the implementation of mono, Di- and trimethylamine is preferably> 90%, more preferably> 95%.

The Working up of the reactor discharge can be carried out in accordance with the person skilled in the art known methods, e.g. according to DD-125 533 (VEB Leuna-Werke).

For the process for the preparation of methylamines with the catalyst according to the invention, the interconnection with a reactor containing a shape-selective catalyst according to US 4,485,261 and PEP-Review, No. 89-3-4, (SRI International, Menlo Park, California).

at optionally used dimethyl ether (DME), trimethylamine (TMA) and / or the optionally used monomethylamine (MMA) In particular embodiments of the invention, this is a respective return current from the worked-up reaction product of the process.

Regeneration of the shaped catalyst bodies after their use in the continuous synthesis of methylamines:
In a further embodiment of the process according to the invention, the catalyst is regenerated after use, regardless of its form, for example after the activity and / or the selectivity has been reduced, by a process in which the regeneration is effected by controlled burning (eg at a temperature in the region of 350.degree to 650 ° C) of the responsible for the deactivation pads. In this case, preference is given to working in an inert gas atmosphere which contains precisely defined amounts of oxygen or Contains oxygen-supplying substances. Such a regeneration process is described inter alia in WO-A-98/55228 and DE-A1-197 23 949 and in particular for catalysts for the preparation of methylamines in JP-08 157 428 and EP-A-0118 193, whose this disclosure is hereby incorporated by reference in its entirety into the subject matter of the present application.

To the regeneration are the activity and / or the selectivity of the catalyst, compared with the condition immediately before regeneration, increased.

Of the to be regenerated catalyst according to the invention is either in the reaction apparatus (reactor) or in a external oven in an atmosphere which is preferably 0.1 to about 20 volume fractions of oxygen supplying substances, especially preferably 0.1 to 20 parts by volume of oxygen, contains a temperature in the range of 350 ° C to 800 ° C, preferably from 400 ° C to 650 ° C and in particular from 425 ° C up to 500 ° C heated. In this case, the heating is preferably at a heating rate of 0.1 ° C / min. up to 20 ° C / min., preferably from 0.3 ° C / min. up to 15 ° C / min. and in particular of 0.5 ° C / min. up to 10 ° C / min. carried out. The heating is preferably carried out under an inert atmosphere.

During regeneration, the catalyst is heated to a temperature at which the mostly organic deposits located there begin to decompose, while at the same time the temperature is regulated by the oxygen content and thus does not increase to such an extent as to damage the catalyst structure or the reactor comes. Slow temperature elevation or low temperature residence by adjusting the corresponding oxygen content and heat output is an important step in preventing local overheating of the catalyst at high organic loadings of the catalyst to be regenerated. The gas load of the oxygen-containing regeneration gas expressed as GHSV (= gas hourly space velocity) is more than 50 standard liters per liter of catalyst per hour (= NI / I (cat) h), preferably more than 100 NI / l (cat) h and more preferably in the range between 150 and 1000 NI / l (cat) h.
(NI = standard liters = volume converted to standard conditions).

Sinks the temperature of the exhaust stream at the reactor outlet to the temperature at the reactor entrance despite increasing amounts of oxygen or oxygen supplying substances in the gas stream and / or increases the concentration of oxygen in the reaction effluent to the input value, so that is Burning off the organic deposits completed. The duration of the treatment is preferably 1 to 72 h, preferably approximately 2 to about 48 h and in particular approximately 3 to about 24 hours.

The subsequent cooling down of the thus regenerated catalyst is preferably carried out so that cooling not too fast, otherwise the mechanical strength of the Catalyst can be negatively influenced. The cooling is preferably carried out under an inert atmosphere.

It may be necessary, the catalyst after the regeneration carried out by calcining, as described above, a rinse with water and / or diluted acids such as hydrochloric acid to be subjected to, if necessary, by contamination of the educts remaining inorganic loading of the catalyst (traces of alkali etc.) to remove. Subsequently may be a new drying and / or recalcining the Catalyst performed become.

In a further embodiment of the method according to the invention, the at least partially deactivated catalyst is washed before heating in accordance with the regeneration procedure with a solvent in the reaction reactor or in an external reactor in order to remove still adhering desired product. The washing is carried out in such a way that, although the products of value adhering to the catalyst can be removed therefrom, the temperature and pressure are not chosen so high that the mostly organic deposits are also removed. Preferably, the catalyst is merely rinsed with a suitable solvent. Thus, all solvents are suitable for this washing process, in which the respective reaction product dissolves well. The amount of solvent used and the duration of the wash are not critical. The washing process can be repeated several times and carried out at elevated temperature. When CO _{2 is used} as the solvent, supercritical pressure is preferred, otherwise the washing process can be carried out under normal pressure or elevated or supercritical pressure. After completion of the washing, the catalyst is generally dried. Although the drying process is generally not critical, the drying temperature should not exceed the boiling point of the solvent used for washing too much to avoid a sudden evaporation of the solvent in the pores, as this can lead to damage to the catalyst.

A preferred embodiment of the preparation process is that the inventive, continuous process for the synthesis of methyla mines must not be interrupted in the regeneration of the catalyst according to the invention, so as to increase the process throughput. This can be achieved by using at least two parallel-connected reactors, which can be operated alternately.

The Catalyst regeneration may be performed such that at least one of the parallel-connected reactors from the respective reaction stage is decoupled and the catalyst contained in this reactor is regenerated, during the course of the continuous process in each stage always at least one reactor for the reaction of the starting material or the starting materials available stands.

Claims (23)

Shaped body containing an aluminosilicate and aluminum oxide, characterized in that the shaped body has a molar Al / Si ratio in the range of 10 to 30 and for pores having a diameter of greater than 1 nm has an at least bimodal pore distribution, wherein the volume of the pores of the shaped body with a diameter greater than 10 nm corresponds to at least 40% of the total pore volume of the molding. moldings according to claim 1, characterized in that it has a molar Al / Si ratio in the range from 11 to 25. moldings according to claim 1 or 2, characterized in that it is for pores with a diameter of greater than 1 nm has a bimodal pore distribution. moldings according to one of the preceding claims, characterized that the volume of the pores of the shaped body having a diameter greater than 10 nm at least 50% of the total pore volume of the shaped body corresponds. Shaped body according to one of the preceding claims, characterized in that it has a BET surface area of ≥ 50 m ² / g. Shaped body according to one of claims 1 to 4, characterized in that it has a BET surface area in the range of 100 to 250 m ² / g. moldings according to one of the preceding claims, characterized that the shaped body in the range of 0.01 to 1.75% by weight of sodium, 0.01 to 1.75% by weight Potassium, 0.01 to 0.35% by weight of titanium and 0.01 to 0.35% by weight of iron, each based on the total weight contains. moldings according to one of the preceding claims, characterized that it is an extrudate with a length: diameter ratio of ≥ 1. moldings according to one of the preceding claims, characterized that he has a cutting hardness of ≥ 10 Newton (N). moldings according to one of the preceding claims, characterized that the aluminosilicate is kaolin. Shaped body according to one of the preceding claims, characterized in that the aluminum oxide is gamma-Al ₂ O ₃ . moldings according to the preceding claim, characterized in that as Preliminary stage for the gamma-alumina, aluminum hydroxide and / or alumina / hydroxide (Boehmite) is used. moldings according to one of the preceding claims, characterized the proportion of aluminum oxide in the molding is ≥50% by weight. Process for producing a shaped article according to a of the preceding claims, characterized in that it is the steps (I) manufacture a mixture containing the aluminosilicate, the alumina as Binder, a pasting agent and a solvent, (II) mixing and compressing the mixture, (III) deforming the compacted Mixture to obtain a shaped body, (IV) drying the molding and (V) calcining the dried shaped article includes. Method according to the preceding claim, characterized in that the deformation according to (III) is effected by extrusion. Method according to one of the two preceding claims, characterized characterized in that the calcining according to (V) at a temperature in the range of 350 to 750 ° C and lasting in the range of 1 to 24 hours. Process for the continuous production of methylamines by reaction of methanol and / or dimethyl ether with ammonia in the presence of a heterogeneous catalyst, characterized that as a catalyst, a shaped body according to one the claims 1 to 13 is used. Method according to the preceding claim, characterized in that the feed stream in addition to methanol and / or dimethyl ether and ammonia monomethylamine, dimethylamine and / or Contains trimethylamine. Method according to one of the two preceding claims, characterized characterized in that the molar C / N ratio in the feed mixture in the range from 0.6 to 4.0. Method according to one of the three preceding claims, characterized characterized in that the reaction temperature is in the range of 250 is up to 500 ° C. Method according to one of the four preceding claims, characterized characterized in that the absolute pressure in the range of 5 to 50 bar lies. Method according to one of the preceding five claims, characterized in that the catalyst space velocity, expressed in kilograms of methanol per kilogram of catalyst per hour, in the range of 0.1 to 2.0 h ^-1. Method according to one of the six preceding claims, characterized characterized in that a regeneration of the catalyst used by targeted burning of the for the deactivation of responsible coverings takes place.