CN1004791B - Palladium/rhenium hydrogenation catalyst and method for producing same - Google Patents
Palladium/rhenium hydrogenation catalyst and method for producing same Download PDFInfo
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Abstract
本发明涉及一种用于制造四氢呋喃、１，４－丁二醇及其混合物的钯－铼催化剂及其制造方法。它由０．５％－１０％的钯、１％－１０％的铼（均以总重量计）及余量的碳载体组成。其中钯呈晶粒形式，其平均粒径为１０－２５毫微米，铼呈高分散相的晶粒形式，其平均粒径小于２．５毫微米。The invention relates to a palladium-rhenium catalyst used for producing tetrahydrofuran, 1,4-butanediol and their mixture and its production method. It is composed of 0.5%-10% of palladium, 1%-10% of rhenium (both by total weight) and the balance of carbon support. Palladium is in the form of grains with an average particle size of 10-25 nanometers, and rhenium is in the form of highly dispersed crystal grains with an average particle size of less than 2.5 nanometers.
Description
The present invention relates to a palladium/rhenium composite catalyst for producing tetrahydrofuran, 1, 4-dibutyl alcohol and their mixture and its production method.
U.S. patent 4176088 discloses a reduced state multi-metal composite catalytic material formed by combining a catalytically effective amount of an adsorbed rhenium oxide component with a porous support material containing a catalytically effective amount of a platinum-group component, the platinum component being present in elemental metallic form and uniformly dispersed in the support material. The patent also discloses a method for manufacturing the composite catalytic material. In this process, a material (typically having been halogen treated) containing a platinum group metal in a predetermined oxidation state is subjected to a substantially anhydrous reduction treatment step prior to introducing a rhenium component into the catalyst using a predetermined rhenium oxide reactant. The patent also describes the use of "platinum" to represent any of the platinum group metals, but only platinum is mentioned in the actual example.
U.S. patent 4157989 discloses a multi-metal composite catalytic material for hydrocarbon conversion. It is formed by combining a catalytically effective amount of a pyrolytic carbonyl rhenium component and a porous carrier material containing a catalytically effective amount of a platinum-series component, the platinum component being uniformly dispersed in the porous carrier material in an elemental metallic state. When the composite catalytic material is applied to a hydrocarbon process requiring the use of a catalyst having a hydrogenation/dehydrogenation function and a carbonium ion forming function, it is said to have excellent activity, selectivity and deactivation resistance. The patent also discloses a process for the manufacture of the composite catalytic material wherein a material containing a predetermined oxidation state platinum group metal and which has typically been subjected to a halogen treatment is subjected to a substantially anhydrous reduction treatment step prior to the introduction of a rhenium component into the catalyst using a predetermined carbonyl rhenium reactant.
In contrast to the above patent, the present invention is a palladium/rhenium composite catalytic material supported on a carbon support. The catalyst of the present invention can provide advantages in that a) the conversion rate of precursors of tetrahydrofuran and 1, 4-butanediol is nearly 100%, b) the selectivity for producing tetrahydrofuran and 1, 4-butanediol is high, c) the product ratio of tetrahydrofuran and 1, 4-butanediol can be controlled, as long as the temperature, contact time and/or space time of hydrogen are changed.
The present invention relates to a palladium and rhenium composite catalyst on a carbon support, the catalyst comprising from about 0.5% to about 10% palladium and from about 1% to about 10% rhenium by weight. The catalyst typically contains 1% to 6% palladium and 3% to 6% rhenium, preferably 3% palladium and 3% rhenium.
The palladium contained in the palladium/rhenium/carbon catalyst of the present invention is in the form of grains having an average particle diameter of 10 to 25 nm, and the rhenium is in the form of grains of a highly dispersed phase having a particle diameter of less than 2.5 nm, preferably less than 1.5 nm. The palladium grain size was determined by H 2/O2 titration and rhenium grain size was determined by Scanning Transmission Electron Microscopy (STEM). The highly dispersed rhenium grains are too small to be measured by X-ray diffraction or by STEM.
The invention also relates to a method for manufacturing the catalyst, which comprises the following steps in sequence:
(1) Impregnating a carbon support with a palladium source (palladium solution) and removing the solvent;
(2) Heating the palladium-impregnated carbon under reducing conditions at a temperature of 150 ℃ to 550 ℃ (preferably 200 ℃ to 300 ℃) for a period of time typically 2 to 5 hours;
(3) A rhenium source (rhenium solution) was coated on the palladium-impregnated carbon and the solvent was removed to produce a palladium/rhenium/carbon catalyst.
The palladium/rhenium/carbon catalyst prepared in step (3) above is heated under reducing conditions at a temperature of 150 to 550 ℃, preferably 200 to 300 ℃, typically for a period of 2 to 5 hours. The reduction reaction may be carried out immediately after step (3) or in a hydrogenator immediately before or simultaneously with the start of the reaction.
During the catalyst synthesis, a group I A or II A metal, such as potassium, sodium, lithium, calcium or magnesium, is preferably present in an amount of about 0.1 to 1 molar percent (based on the number of moles of carbon in the support). The surface area of the support is typically greater than 650 m 2/g (preferably greater than 900 m 2/g).
The invention also relates to a process for the selective production of tetrahydrofuran, 1, 4-butanediol or mixtures thereof by hydrogenating a hydrogenatable precursor such as maleic anhydride, maleic acid, fumaric acid, succinic acid, malic acid, succinic esters such as dimethyl succinate, r-butyrolactone or mixtures of two or more of the foregoing compounds in an aqueous medium or in an organic solvent medium at a reaction temperature of about 130 ℃ to 285 ℃, a hydrogen pressure of about 300Psig (2 MPa to 5000Psig (35 MPa), a hydrogen hourly space time of about 1 to 10 minutes, and a reaction feed in the presence of a palladium-rhenium catalyst on a carbon support as described above for a period of about 0.5 to 7 hours.
The catalyst according to the invention has the characteristics that (a) the precursors are converted to essentially 100%, b) the selectivity towards the tetrahydrofuran/1, 4-butanediol product produced is good, c) the yield of tetrahydrofuran/1, 4-butanediol can be controlled by varying the temperature, the contact time and/or the space-time of the hydrogen to the desired operating range, etc., generally the higher the temperature, the longer the contact time and/or the space-time of the hydrogen is greater, the higher the ratio of tetrahydrofuran/1, 4-butanediol obtained and vice versa. By hydrogen hourly space is meant the reaction volume divided by the flow rate of hydrogen under the reaction conditions.
The invention also relates to a process for the continuous production of tetrahydrofuran, 1, 4-butanediol or mixtures thereof with normal C 4 hydrocarbons or aromatic hydrocarbons, which comprises the following steps:
(1) Oxidizing hydrocarbons to produce maleic anhydride;
(2) Collecting the maleic anhydride produced in step (1) in an aqueous solution;
(3) Under the above-mentioned reaction conditions, an aqueous maleic acid solution is reacted with hydrogen in the presence of the palladium/rhenium/carbon catalyst of the present invention.
The palladium-rhenium catalyst on the carbon carrier can be used for the reaction, the maleic acid can be basically completely converted in the prepared aqueous solution medium, and the production selectivity of tetrahydrofuran/1, 4-butanediol is good. The palladium-rhenium catalyst on carbon support of the present invention is extremely effective for continuous production processes.
Detailed description of the invention
Catalyst:
A process for preparing the catalyst comprises (a) applying a solution of a palladium compound to a carbon support and removing the solvent, (b) heating the carbon impregnated with the palladium compound obtained in step (a) under reducing conditions at 150 to 550 ℃ and preferably at 200 to 300 ℃, cooling the composite palladium catalyst (Pd/C) on the carbon support obtained in step (b), and (C) applying a solution of a rhenium compound to the composite palladium catalyst and removing the solvent.
The palladium on carbon impregnated with the rhenium compound obtained in step (C) above is heated under reducing conditions at 150 to 550 ℃, preferably 200 to 300 ℃, preferably for a period of 2 to 5 hours. The heating may be performed immediately after step (c), or may be performed in the hydrogenation apparatus immediately before the reaction occurs or simultaneously with the start of the reaction.
The palladium/rhenium/carbon catalyst is preferably prepared in the presence of a group I A or II A metal, such as potassium, sodium, lithium, calcium or magnesium. The above-mentioned metals may be contained in the carbon support produced or may be additionally added. If the carbon support is free of the above metals, the carbon support may be impregnated with a solution of a group I A or II A metal compound, such as Licl, nacl, kcl, KOH, naOH, cacl 2 or Mgcl 2、6H2 O. It is believed that group I A or II A metals are beneficial to the microstructure of the catalyst.
Another method of adding the group I A or II A metal is to add a group I A or II A metal compound to a solution of a palladium compound or to add a group I A or II A metal by palladium with a palladium compound such as K 2PdCl4 or Na 2Pdcl4 that also contains a group I A or II A metal. Preferably, the group I A or II A metal is added to the carbon support and the impregnated carbon is calcined at a temperature of 200 ℃ to 400 ℃ for 2 to 6 hours before impregnating the carbon support with the palladium source.
The solution of palladium and rhenium compounds may be applied to the carbon by immersing or suspending the carbon support material in the solution or spraying the solution onto the carbon. The solution containing the palladium compound is usually an acidic aqueous medium containing hydrochloric acid and a certain amount of the palladium compound, and thus the catalyst produced contains a specified amount of palladium. The palladium compound is typically Pdcl 2 but may also be a nitrate, carbonate, carboxylate, acetate, acetylacetonate or amine. The solution containing the rhenium compound is typically an aqueous medium containing a quantity of the rhenium compound, so that the catalyst produced contains a specified quantity of rhenium. The rhenium compound is typically Re 2O7, but may also be an ammonium perrhenate or an alkali metal perrhenate.
Heating under reducing conditions means heating in a reducing medium (preferably hydrogen). The sample is typically reduced by heating the sample in a He gas stream at 150℃for about 1 hour, then in a He/H 2 gas stream (50: 50 molar ratio of He/H 2) at 150℃for about 1 hour, and finally in a He/H 2 gas stream (50: 50 molar ratio of He/H 2) at 150℃to 550℃for up to 3 hours.
In the catalyst preparation process, if a group I A or II A metal is contained in the carbon support, large crystal grains (about 0.2 μm) of ReO - 4 salt contained in the catalyst can be observed by X-ray diffraction and scanning transmission electron microscopy. If the catalyst is subjected to reducing conditions again (e.g., during maleic acid hydrogenation) and then measured, no salts of ReO - 4 or phases containing group I A or II A metal salts can be detected. While the catalyst still contains the palladium and rhenium crystallites described above.
The catalytic method comprises the following steps:
If normal C 4 hydrocarbons are used as reaction raw materials, the process requires no special requirements on equipment, energy and time (whereas in the prior art relating to hydrogenation, the separation and purification of maleic anhydride are required). The catalytic process generally comprises the steps of (a) reacting n-butane or benzene in an oxygen-containing gas in the presence of a mixed oxidation catalyst of vanadium/phosphorus to oxidize n-butane in the vapor phase to maleic anhydride, (b) collecting the maleic anhydride, quenching with water to produce an aqueous maleic acid solution having a concentration of about 40% by weight, and (c) reacting the solution produced in step (b) with hydrogen in the presence of a palladium/rhenium/hydrocarbon catalyst.
The oxidation step (a) is preferably carried out at a temperature of 300 ℃ to 600 ℃ and a pressure of 0.5 to 20 atmospheres (50 to 2000 KPa), the hydrogenation step (C) is carried out at a temperature of about 150 ℃ to 275 ℃ and a hydrogen pressure of about 300 lbs/inch 2 (MPa to 5000 lbs/inch 2 (35 MPa).
The liquid phase hydrogenation of the present invention may be carried out in a stirred tank reactor or in a fixed bed reactor using conventional equipment and techniques. The hydrogen is added continuously, typically with a non-inert diluent gas in an amount well above stoichiometry. Unreacted hydrogen may be returned to the reactor with the recycle gas stream, and a precursor solution, such as a maleic acid solution, may also be added continuously, at a concentration ranging from a dilute solution to near maximum solubility, typically about 30% to 40% by weight. The catalyst carbon support used in the stirred tank reactor had a particle size of about 200 mesh and the support used in the fixed bed reactor had a larger particle size [ 1/4'' (0.64 cm) through 60 mesh ]. The amount of catalyst may depend on a variety of factors such as the size and configuration of the reactor. The contact time and similar other factors vary, for example, for a 60 ml volume reactor, 25g of catalyst is preferred. The catalyst content used was 3% palladium/3% rhenium/carbon.
The invention is further illustrated by the following examples, in which all hydrogenation experiments were carried out in a reactor having a diameter of 0.5' ' (1.27 cm) and a length of 30' ' (76 cm), unless otherwise indicated, and having a structure of 20.1/2' ' corrosion and heat resistant nickel-based alloy carbon tube of Berming's Wire Gauge (BWG), a wall thickness of 0.035' ' (0.09 cm) and an inner diameter of 0.430' ' (1.1 cm). The volume of the reactor was calculated from the packed catalyst volume. In all cases, the packed bed was 25 "(63 cm) long. The voids are filled with inert silicon carbide. The calculated reaction volume of the resulting catalyst was 59.49 cm, which was used to determine the surface reaction residence time, i.e., the contact time.
The reactor is operated in a concurrent, updraft mode, the addition of liquid maleic acid or other precursors and hydrogen are measured respectively, then the mixture is added into a T-shaped mixing tube at the bottom of the reactor, the reaction raw materials are fully mixed and preheated, the reaction is completed in an inert packed bed part, excessive hydrogen is added, the product is discharged through a valve, and the pressure of the valve is reduced from the reaction pressure to the atmospheric pressure. Most of the liquid product collected contained Tetrahydrofuran (THF) and 1, 4-Butanediol (BDO) with little by-product. The vapor stream of the reaction was passed through a series of vapor/liquid separation vessels, the first separator at room temperature, then a water/ice trap, and then two (in series) dry ice/acetone traps. The main collection is tetrahydrofuran and a small amount of monohydric alcohol and butyrolactone. The trap described above is used because small amounts of liquid/vapor are difficult to separate.
The maleic acid used in the following examples was prepared (unless otherwise specified) by adding 500 g of certified maleic anhydride (FISHER SCIENTIFIC, inc.) to 1190 g of distilled water. Hydrogen was compressed from a 99% purity hydrogen cylinder to a reaction pressure of about 2500 lbs/inch 2 (17 MPa) at a hydrogen addition rate of 1000 ml/min (standard temperature and pressure) equal to the hourly space (6 minutes) of hydrogen under reaction conditions (i.e., pressure of 2500 lbs/inch 2 (17 MPa) and temperature of 200 ℃). The hydrogen gas time was 6 minutes (unless otherwise noted). The catalyst is granular and has a particle size of less than 20 meshes. The "SPACE TIME YIELD" space time rate unit is in grams (product)/kg-hours (catalytic time) in all the titles and examples.
Example 1
The catalyst on a 3% palladium/3% rhenium/carbon support (i.e., 3% Pd/3% Re/C) was prepared by washing the carbon (size 12X 30) with a sodium hexametaphosphate polychlorinated biphenyl detergent, calcining at 200℃for 2 hours, then calcining at 400℃for 2 hours, the treated carbon having a surface area of 1000-1300 m 2/g and a void fraction of 0.6 cm 3/g. Palladium and rhenium were sequentially deposited on the treated carbon by combining 2.5 g of PdCl 2 with 10 ml of concentrated hydrochloric acid and 80 ml of distilled water to form a solution, adding 50 g of treated carbon to the solution, stirring at room temperature from time to time, and drying the slurry at 110℃for 18 hours after 3 hours.
The sample was reduced by heating at 150℃in a He gas stream (flow rate of 1000 cm 3/min) for 1 hour, then at 150℃in a He/H 2 gas stream (He/H 2 molar ratio of 50:50, flow rate of 1000 cm 3/min) for 1 hour, and finally at 300℃in a He/H 2 gas stream (He/H 2 molar ratio of 50:50, flow rate of 1000 cm 3/min) for 3 hours. The sample was rapidly cooled to 50 ℃ in an atmosphere of He/H 2, ammonia gas was added while the sample was cooled to room temperature. After thirty minutes in the N 2 gas stream, O 2/N2 gas stream (molar ratio of O 2/N2: 1:99) was added at room temperature and the sample was purified for 2 hours.
Then, 5g Re 2O7 was added to 50 ml distilled water, and 19.7 ml rhenium solution and 70 ml distilled water were added to a 1000 ml flask together with 50 g palladium on carbon catalyst. After 3 hours at room temperature, the slurry was dried, reduced and the product was passivated by the palladium on carbon catalyst passivation method described above. The product was 3% palladium/3% rhenium/carbon catalyst.
The palladium/rhenium/carbon catalyst prepared in this example was measured by X-ray diffraction, scanning transmission electron microscopy and H 2/O2 titration, and the measurement showed that the average particle size of the palladium crystallites was about 150X-200X (15-20 nm). Rhenium grains are too small to be measured by X-ray diffraction or scanning transmission electron microscopy and therefore, it can only be estimated that rhenium has a particle size of less than 25X (2.5 nm).
The average grain size of KReO 4 grains was about 0.2 microns as measured by microscopy and crystallization analysis techniques. The small grained highly dispersed rhenium phase described above was observed to contact some of the palladium grained phase by microscopy. The carbon support can be used to prepare a catalyst containing 0.36 mole% K.
Examples 2 to 14
A3% Pd/3% Re/C catalyst was prepared as in example 1, and this catalyst was fed into a reactor having a diameter of 0.5 ", the rate of maleic acid addition was adjusted so that the contact time was 0.9 hours to 5.5 hours (e.g., the rate of maleic acid addition was 0.5 ml/min, resulting in a reaction or contact time of 2.0 hours), and the flow rate of hydrogen was adjusted so that the hydrogen time was 3 or 6 minutes. The hydrogenation reaction was carried out at reaction temperatures of 175 °, 180 °, 190 °,200 °, 215 ° and 225 °, with successive samples of the reaction product. The molar percentages (based on the amount of carbon) of tetrahydrofuran and 1, 4-butanediol and monohydric alcohol by-products such as butanol, propanol, etc., as well as r-butyrolactone intermediate products in the product are shown in Table 1 under various reaction conditions. These data are averages of several determinations taken after stable conditions are reached.
Since the amount of maleic acid was not measured, this indicates that the conversion of maleic acid was substantially complete. Thus, molar percentages may represent the selectivity of the product and the content of the particular component produced. The space-time rates are also listed in the table. The space-time rate is the amount of product obtained when a unit weight of metal catalyst is added per unit time. The results show that the method has good selectivity for producing tetrahydrofuran/1.4-butanediol, the yield of tetrahydrofuran/1.4-butanediol increases with the increase of temperature, the increase of contact time and/or the increase of hydrogen space time, and the reaction conditions can be controlled to adjust the reaction yield from the condition that 1.4-butanediol is basically only produced to the condition that tetrahydrofuran is basically only produced.
(See Table 1)
Examples 15 to 18
A1% Pd/3% Re/C catalyst was prepared as in example 1, except that PdCl 2 was used in an amount of 1/3 of that used in example 1, the maximum temperature for reduction after palladium deposition was 350℃and the maximum temperature for reduction after rhenium deposition was 150 ℃.
The hydrogenation was carried out at a reaction temperature of 180℃as described in examples 2 to 14, and the flow rate of maleic acid was adjusted so that the contact time was 2.1 to 3.5 hours. The test results illustrated in Table 2 show that the yield of tetrahydrofuran/1, 4-butanediol increases with increasing contact time.
(See Table 2)
Examples 19 to 24
A3% Pd/1% Re/C catalyst was prepared as in example 1, except that the amount of Re 2O7 was 1/3 of that used in example 1. As in examples 2-14, the hydrogenation was carried out at various reaction temperatures and reaction contact times, and the results shown in Table 3 indicate that increasing the reaction temperature and/or increasing the reaction contact time, resulted in an increase in tetrahydrofuran/1, 4-butanediol yield. Nor was maleic acid found as a result of the assay, indicating that the maleic acid had been substantially completely converted.
(See Table 3)
Example 25
A10%/Pd/3% Re/C catalyst was prepared as in example 1 except that the amount of PdCl 2 was 10/3 of that used in example 1. 53.76 g of dimethyl succinate and 6.0 g of water are introduced into a pressure vessel and contacted with 30 g of 10% Pd/3% Re/C catalyst at a temperature of 285℃and a hydrogen pressure of 2 g at a pressure of 2500 lbs/inch for 2 hours, the reaction product containing 62.2 g of tetrahydrofuran, 18.6 g of butanol, 4.7 g of propanol and 14.5 g of r-butyrolactone, based on the amount of carbon.
Examples 26 to 27
A3% Pd/3% Re/C catalyst was prepared as in example 1, except that the maximum temperature in the two reduction steps was 200℃instead of 300℃and the hydrogenation was carried out as in examples 2-14 using the reaction conditions given in Table 4. The results show that the contact time is long and the yield of tetrahydrofuran/1, 4-butanediol is high.
(See Table 4)
Examples 28 to 32
A3% Pd/3% Re/C catalyst was prepared as in example 1, except that the reaction step after deposition of the palladium compound was carried out at a maximum temperature of 500℃instead of 300 ℃. Hydrogenation was carried out as in examples 2-14 using the reaction conditions given in Table 5. The results demonstrate the advantages of the catalysts of the present invention.
(See Table 5)
Example 33
A6% Pd/3% Re/C catalyst was prepared as in example 1, except that PdCL 2 was used in an amount twice that of example 1. As in examples 2 to 14, the hydrogenation was carried out at a reaction temperature of 180℃for a contact time of 2.1 hours. The molar percentage ratio of the product to the byproduct is tetrahydrofuran 67/1, 4-butanediol 19/r-butyrolactone 5, succinic acid 1, and the space-time ratio is 239.
Example 34
A6% Pd/3% Re/C catalyst was prepared as in example 1, except that PdCL 2 was used in an amount twice that of example 1 and Re 2O7 was also used in an amount 2 times that of example 1. As in examples 2 to 14, the hydrogenation was carried out at a reaction temperature of 180℃for 2.0 hours, and the molar percentage of the product/by-product was tetrahydrofuran 40/1, 4-butanediol 50/monohydric alcohol 9/r-butyrolactone 1, with a space-time ratio of 300.
Example 35
The catalyst of example 1 was used in the hydrogenation experiments as in examples 2-14, except that an aqueous fumaric acid solution was added at a concentration of 9% by weight. The reaction temperature is 180 ℃, the reaction time is 2.0 hours, and the molar percentage (proportion) of the product is that tetrahydrofuran/1, 4-butanediol/monohydric alcohol/r-butyrolactone is 19/71/8/2. The space-time ratio was 72.
Example 36
A process for the continuous production of tetrahydrofuran/1, 4-butanediol from n-butane via the unseparated maleic acid intermediate product is described by preactivating 3% by atomic number of V/P/OX in 2% by weight of SiO 2, granulating the catalyst with a particle size of 1/8'', adding 70 g of the catalyst to an upright No. 316 stainless steel fixed bed reactor with a diameter of 1'', a height of 12'', and heating the reactor in a fluidised sand bath to achieve a controlled temperature. The reactor was connected to a transfer line which acted to (1) multiplex the air stream containing 1.5% n-butane through a preheater coil in a sand bath and then into the bottom of the reactor to contact the catalyst bed, (2) the product was passed through a vent line (heating the vent line to above 200 ℃ to avoid maleic anhydride deposition) and then into a separator where 80% of the exhaust gas was passed through water to absorb maleic anhydride which was available for the subsequent hydrogenation reaction.
The remaining product stream is passed through a heated conduit to a binary gas chromatography apparatus for product analysis. A heated back pressure valve was installed in the outlet channel at the front of the chromatograph to raise the operating pressure of the system from atmospheric pressure (100 KPa) to a maximum pressure of 125 lbs/inch 2 (870 KPa). The operating temperature is 380 ℃ to 450 ℃ and the contact time (at standard temperature and pressure) is 1 to 7 seconds. The analysis system can determine N 2、O2、CO、CO2、H2 O, N-butane, maleic anhydride, ethylene, furan, methyl ethyl ketone, acetic acid, and acrylic acid. The maleic acid solution was colorless.
The crude maleic acid intermediate was hydrogenated as in examples 2-14 using the 3% Pd/3% Re/C catalyst prepared in example 1. The concentration of maleic acid was 33%, the rate of addition of maleic acid was 0.5 ml/min, the corresponding contact time was 2 hours and the reaction temperature was 200 ℃. The molar percentage ratio of the product by-product (i.e. tetrahydrofuran/1, 4-butanediol/monohydric alcohol) was 30/58/12. The space-time ratio was 280.
Example 37 and comparative examples A and B
The purpose of comparing this example with comparative examples A and B is to demonstrate that the activity of the catalyst of the present invention (example 37) is not inferior to that of both catalysts A and B. In this example and comparative examples a and B, the catalyst on the carbon support contained% Pd and 3% re. The catalyst of the present invention (example 37) was prepared as in example 1.
The catalyst of comparative example A was prepared by calcining 100 grams of activated carbon at atmospheric pressure, at 200℃for 2 hours, and then at 400℃for 2 hours. The carbon was cooled and then sieved to give 54.0 grams of 20 mesh size calcined carbon. A rhenium solution having a concentration of 0.076 g/ml was prepared by adding 5.0 g Re 2O7 to 50 ml distilled water. Then, 19.7 ml of rhenium solution, 10ml of concentrated hydrochloric acid, 50 ml of distilled water, 2.5 g of PdCl 2, and 50 g of calcined carbon were added to a 1000 ml flask, stirred from time to time, and after 3 hours the slurry was dried at 110 ℃ for 18 hours. The Pd/Re/C catalyst was then reduced by heating at 150℃for 1 hour in nitrogen, then at 150℃for 1 hour in a 50%/50% N 2/H2（N2/H2 ratio, finally at 300℃for 3 hours in a 50%/50% N 2/H2 ratio, cooling and then passivating the catalyst for 3 hours in a 1% O 2/N2 atmosphere.
The catalyst of comparative example B was prepared by calcining 100 grams of activated carbon at atmospheric pressure, at 200℃for 2 hours, and then at 400℃for 2 hours. The carbon was cooled and then sieved to give 61.0 grams of 20 mesh size calcined carbon. A rhenium solution having a concentration of 0.076 g/ml was prepared by adding 5.0 g Re 2O7 to 50ml distilled water. Then, 19.7 ml of rhenium solution was added to a 1000 ml flask, and 50 g of calcined carbon and 70 ml of distilled water were added to the flask, stirred from time to time, and after four hours the slurry was dried at 110 ℃ for 18 hours.
The reduction of Re/C material was carried out by adding 1 hour at 150℃in nitrogen, heating again at 150℃in N 2/H2 (50%) for 1 hour, and then at 300℃in N 2/H2 (50%/50%) for 3 hours. Re/C material was passivated in 1%O 2/H2 for 3 hours. Then, 2.5 g PdCL 2 g, 70 ml distilled water and 10 ml concentrated HCl were added together into a 1000 ml flask. Re/C material was added to the solution and the slurry was left at room temperature for 3 hours and dried at 110℃for 18 hours. The reduction was carried out under conditions of heating at 150℃for 1 hour in nitrogen, then at 150℃in 50%/50% N 2/H2 for 1 hour, then at 300℃in 50%/50% N 2/H2 for 3 hours. After cooling, the catalyst was passivated in 1%O 2/H2 hours.
The hydrogenation was carried out under conditions such that the catalyst on a carbon support contained 3% palladium and 3% rhenium in each case, weighing 18 grams, and the catalyst was charged to a 0.37 inch diameter, corrosion resistant, heat resistant nickel base alloy carbon, high pressure reactor tube of approximately 2 feet in length.
The reaction tube was heated with a three-stage vertical electric furnace to purge the nitrogen from the reaction system and the pressure in the reactor was raised to 2500 lbs/inch 2 with hydrogen. The reactor was heated slowly to the temperature at which the reaction took place, maintaining a steady flow rate of hydrogen (2 litres/minute) (standard temperature and pressure), adapting the catalyst to the preheating, and after the completion of the preheating, a maleic acid solution with a concentration of 30% by weight (at a certain flow rate) was added. The reactants are added in a forward flow direction and flow upward. The reaction product and excess hydrogen are vented through a back pressure regulator valve. The reaction products were sampled at half an hour intervals.
The microstructure of the catalyst of comparative example A was such that both rhenium and palladium were deposited on the catalyst, the average particle size of the palladium crystallites contained therein being only 7 nm, with rhenium being in the highly dispersed phase. After use, the palladium grains were larger as measured by X-ray diffraction, but no metallic rhenium was detected. As seen from the microstructure of the catalyst of comparative example B, rhenium was deposited and then palladium was deposited, the average particle size of the palladium crystallites contained therein prior to use being only 8 nm, and the average particle size of the large crystallites of rhenium being about 50 nm. And the connection between the palladium and rhenium phases is not obvious. After use, the palladium and rhenium phases are amorphous and therefore undetectable by X-ray diffraction.
The reaction temperature, contact time and ratio of the product obtained as a result of the reaction to the side product are shown in Table 6, and the results show that the catalyst of the present invention can completely convert maleic acid, and has good selectivity for the production of tetrahydrofuran/1, 4-butanediol, whereas the catalysts of comparative examples A and B cannot completely convert maleic acid and have poor selectivity.
(See Table 6)
Examples 38 to 47
The following examples were tested by adding different reactants, solutions of different concentrations and water and organic solvents, and using the catalyst of example 1. The added reaction solution, reaction conditions and results are shown in tables 7 and 8. In all cases, the space time of the hydrogen gas was 6 minutes.
(See Table 7, table 8)
Comparative example C
The procedure of example 1 was repeated except that the carbon support was immersed in hydrochloric acid to reduce the potassium content (less than 0.001 mol%) of the carbon support prior to the deposition of palladium and rhenium. The microstructure of the catalyst was changed to change the size of palladium crystallites, which were measured by H 2/O2 titration to have a particle size of only 5 nm. Hydrogenation was carried out at 180℃in the usual manner in columns 2 to 14 for a duration of 2 hours and 2.2 hours, respectively, with a selectivity to tetrahydrofuran/1, 4-butanediol of 13/29 and a space-time ratio of 325 using the catalyst of example 1 and a selectivity to tetrahydrofuran/1, 4-butanediol of 33/19 and a space-time ratio of 210 using the catalyst with potassium washout.
Example 48
The 3% Pd/3% Re/C catalyst (0.5 mole% sodium added to the potassium-washed carbon) was prepared by calcining a carbon having a size of 12X 30 washed with sodium hexametaphosphate polychlorinated biphenyl detergent at 200℃for 2 hours, and then at 400℃for 2 hours. The 20 mesh sieve was used to screen out carbon powder and fine carbon particles, and 200 g of the 20 mesh carbon obtained was added to 4 liters of 1M hydrochloric acid. The slurry was allowed to stand for 24 hours, then the carbon was collected in a fritted funnel, washed with 4 liters of distilled water, repeatedly washed with acid, and then the carbon was dried at 110 ℃ for 18 hours, yielding 190.3 grams of potassium-washed carbon. To 70 ml of distilled water was added 1.3 g of sodium chloride to prepare a solution, to which was added 50.0 g of potassium-free carbon, and after stirring at room temperature for 3 hours, the slurry was dried at 110℃for 18 hours. 2.5 g of PdCl 2 and 10 ml of concentrated hydrochloric acid, 65 ml of distilled water were prepared as a solution, to which sodium-containing carbon was added, and stirred at room temperature for some time, after 3 hours, the slurry was dried at 110℃for 18 hours. Then, the Pd/C sample was heated in a He gas stream at a flow rate of 100 cm 3/min at 150℃for 1 hour, in a He/H 2 gas stream (both flow rates 100 cm 3/min) at 150℃for 1 hour, and finally in a He/H 2 gas stream (flow rates as above) at 300℃for 3 hours. Then cooled in a He/H gas stream and then used for 1.5%. The resulting solid was passivated with oxygen (in nitrogen) for 18 hours.
48.3 G of passivated Pd/C solid was added to 19 ml of a 0.2MRe 2O7 solution (this solution was formulated with 51 ml of water), stirred at room temperature from time to time, after 3 hours, the slurry was dried at 110℃for 18 hours, and the sample was then reduced and passivated under the above conditions to give 47.8 g Pd/Re/C catalyst.
The hydrogenation was carried out with 27 g of catalyst and 35% by weight of aqueous maleic acid at 190℃under H 2 gas pressure of 2500 lbs/inch 2 (17 MPa) and a contact time of 2.2 hours and a hydrogen hourly space of 6 minutes. The molar percentage of the reaction product (based on the amount of carbon) was THF-55/BDO-34/-monol-8/r-butyrolactone-3 and the space-time ratio was 240.
Examples 49 to 51
The 3% Pd/3% Re/C catalyst was prepared by adding 9.6G NaPdCl 4·3H2 O to 86 ml distilled water, adding 100G carbon (leached CC-521-G) to this solution, standing at room temperature for 1 hour, and then drying the slurry by a steam bath with stirring. 4.0 g NaOH was added to 88 ml distilled water, the carbon was immersed in the NaOH solution for 2 hours, the carbon was washed with distilled water until no chloride was present, 150 g palladium on carbon sample was recovered after drying, and 45 g palladium on carbon support was dried at 110℃for 18 hours. Heating was performed again, first at 150℃in a He gas flow (He flow rate of 100cm 3/min), then at 150℃in a He/H 2 gas flow (each flow rate of 100cm 3/min) for 1 hour, and finally at 300℃in a He/H 2 gas flow for 3 hours. After cooling in a He/H 2 gas stream, the sample was passivated with 1.5% oxygen (in nitrogen) for 18 hours. Then, to a solution of 11.5 ml of 0.2MRe 2O7 and 38.5 ml of distilled water, 29.38 g of reduced Pd/C was added, and after 3 hours at room temperature, the slurry was dried at 110℃for 18 hours. The Pd/Re/C catalyst prepared was reduced and passivated in the manner described above to give 29.44 g of catalyst.
The hydrogenation was carried out as in examples 2-14, with the reaction temperature and contact time shown in Table 9, and in three examples, the hydrogen pressure was 2500 lbs/inch 2 (17 MPa) and the hydrogen hourly space time was 6.0 minutes.
(See Table 9)
Comparative examples D to H
Sequential deposition of palladium and rhenium without intermediate products
A3% Pd/3% Re/C catalyst was prepared by calcining 100 grams of carbon (12X 30 in size, washed with sodium hexametaphosphate polychlorinated biphenyl detergent) at 200℃for 2 hours and then at 400℃for 2 hours. 65.25 g of 20 mesh carbon was separated. Palladium and rhenium were sequentially deposited on the calcined and screened carbon by adding 50 grams of calcined carbon to a solution containing 25 grams of PdCl 2 and 10 milliliters of concentrated hydrochloric acid and 75 milliliters of distilled water, stirring at room temperature for about 3 hours, drying the slurry at 110 ℃ for 18 hours, taking one gram of the dried Pd/C sample for analysis, adding the remaining sample (50.31 grams) to a solution of 19.86 milliliters of 0.2MRe 2O7 and 65 milliliters of distilled water, stirring at room temperature for about 3 hours, and drying the slurry at 110 ℃ for 18 hours. One gram of the dried Pd/Re/C sample was taken for analysis and the remaining sample was heated, first at 150℃in a He gas stream (flow rate 100 cm 3/min) for 1 hour, then at 150℃in a He/H 2 gas stream (flow rates each 100 cm 3/min) for 1 hour, and then at 300℃in a He/H 2 gas stream for 3 hours. The sample was cooled to room temperature and the reduced Pd/Re/C sample was passivated in 1.5% oxygen (nitrogen containing gas) for 18 hours with a yield of 46.68 grams of passivated reduced Pd/Re/C catalyst.
Hydrogenation was carried out as in examples 2 to 14, and the reduction temperature, the reaction contact time and the test results are shown in Table 10. The results indicate that the reactants are not completely converted and that the selectivity of the reaction products is poor.
(See Table 10)
Examples 52 to 56
400 G of carbon (12X 30 carbon size, washed with sodium hexametaphosphate polychlorinated biphenyl cleaner) was added to 1M hydrochloric acid and after 24 hours the carbon was collected in a dissolution funnel and then washed with distilled water until chloride free. The acid treatment was reversed and washed with water and the carbon was dried at 110 ℃ for 48 hours. 385.3 grams of acid washed carbon was recovered for use in the following steps.
A3% Pd/3% Re/C catalyst (also containing 0.30 mole% magnesium in the catalyst of example 52) was prepared by first adding 96.0 grams of the acid-washed carbon to a solution containing 4.82 grams of MgCl 2、6H2 O and 150 milliliters of distilled water, stirring at room temperature for 3 hours, drying the slurry at 110℃for 18 hours with constant stirring, calcining the Mg/C sample at 200℃for 2 hours, then calcining at 400℃for another 2 hours, and screening the calcined Mg/C sample with a 20 mesh screen.
A solution was prepared with 2.5 g of PdCl 2 and 10ml of concentrated hydrochloric acid in 75 ml of distilled water, to which 50.0 g of calcined Mg/C was added, and after 3 hours at room temperature, the slurry was dried at 110℃for 18 hours with continuous stirring. The Pd/C-M sample was then reduced by heating, first at 150℃in a flow of He at a flow rate of 100 cm 3/min for 1 hour, then at 150℃in a flow of He/H 2 (both at a flow rate of 100 cm 3/min) for 1 hour, and finally at 300℃in a flow of He/H 2 for 3 hours. The sample was cooled to room temperature in a stream of He/H 2 and then passivated in 1.5% O 2/N2 for 18 hours.
47.95 G of reduced Pd/C-Mg sample was added to a solution of 19 ml of 0.2MRe 2O7 and 60ml of distilled water, left at room temperature for 3 hours, then the slurry was dried at 110℃for 18 hours, after palladium addition, the Pd/Re/C-Mg sample was reduced as described above and the reduced Pd/Re/C catalyst was passivated in 1.5% oxygen nitrogen for 18 hours with a yield of passivated reduced Pd/Re/C-Mg catalyst of 48.34 g.
The catalyst of example 53, which contained 0.30 mole% calcium in addition to 3% Pd/3% Re/C, was prepared by adding 2.66 grams of CaCl 2 to 150 milliliters of distilled water to prepare a solution, adding 96.0 grams of acid washed carbon to this solution, stirring at room temperature for 3 hours, and after 3 hours, drying the slurry at 110℃for 18 hours with constant stirring. The Ca/C sample was calcined at 200℃for 2 hours and then at 400℃for 2 hours, and the calcined Ca/C sample was screened with a 20-mesh screen.
2.5 G of PdCl 2 and 10ml of concentrated hydrochloric acid were added to 75 ml of distilled water to prepare a solution, 50.0 g of calcined Ca/C sample was added to this solution, left to stand at room temperature for 3 hours, then the slurry was dried at 110℃for 18 hours with constant stirring, the Pd/C-Ca sample was reduced by heating, first at 150℃for 1 hour in a He gas stream (flow rate of 100 cm 3/min), then at 150℃for 1 hour in a He/H 2 gas stream (flow rates of 100 cm 3/min), finally at 300℃for 3 hours in a He/H 2 gas stream, the sample was cooled to room temperature in a He/H 2 gas stream, and then passivated in 1.5% O 2/N2 for 18 hours.
Then, 49.0 g of the reduced Pd/C-Ca sample was added to a solution of 19.35 ml of 0.2MRe 2O7 and 65 ml of distilled water. After 3 hours at room temperature, the slurry was dried at 110℃for 18 hours, after palladium addition, the Pd/Rc/C-Ca sample was reduced as described above and the reduced Pd/Re/C-Ca catalyst was passivated in 1.5% O 2/N2 for 18 hours. The yield of the passivated reduced Pd/Re/C-Ca catalyst was 50.28 g.
The catalyst of example 54, which contained 0.30 mole% K in addition to 3% Pd/3% Re/C, was prepared by adding 1.38 g KOH to 150 ml distilled water to prepare a solution, adding 96.0 g acid-washed carbon to the solution, stirring at room temperature for 3 hours, drying the slurry at 110℃for 18 hours with constant stirring, calcining the K/C sample at 200℃for 2 hours, and further calcining at 400℃for 2 hours, and screening the calcined K/C sample with a 20-mesh sieve.
2.5 G of PdCl 2 and 10 ml of concentrated hydrochloric acid are added to 75 ml of distilled water to prepare a solution, 50.0 g of calcined K/C are added to this solution, after 3 hours of standing at room temperature, the slurry is dried at 110℃for 18 hours with constant stirring, then the Pd/C-K sample is reduced by heating, first at 150℃for 1 hour in a He gas stream at a flow rate of 100 cm 3/min, then at 150℃for 1 hour in a He/H 2 gas stream (both flow rates of 100 cm 3/min), finally at 300℃for 3 hours in a He/H 2 gas stream and then passivated in 1.5% O 2/N2 for 18 hours.
Next, 48.4 g of the reduced Pd/C-K sample was added to a solution of 19.10 ml of 0.2MRe 2O7 and 65 ml of distilled water, and after 3 hours at room temperature, the slurry was dried at 110℃for 18 hours, then after palladium addition, the Pd/Re/C-K sample was reduced as described above, and the reduced Pd/Re/C-K catalyst was passivated in 1.5% O 2/N2 for 18 hours. The yield of the passivated reduced pd/Re/C-K catalyst was 48.67 g.
The catalyst of example 55, which contained 0.36 mole% Li in addition to 3% Pd/3% Re/C, was prepared by adding 1.17 g LiCl to 150 ml distilled water to make a solution, adding 96.0 g acid-washed carbon to the LiCl solution, stirring at room temperature for 3 hours, drying the slurry at 110℃for 18 hours with constant stirring, calcining the Li/C sample at 200℃for 2 hours, and then calcining at 400℃for 2 hours. The calcined Li/C sample was screened with a 20 mesh screen.
To 80 ml of distilled water, 2.5 g of PdCl and 10 ml of concentrated hydrochloric acid were added to prepare a solution, to which 50.0 g of calcined Li/C sample was added, and after standing at room temperature for 3 hours, the slurry was dried at 110 ℃ for 18 hours with continuous stirring. The Pd/C-Li sample was then reduced by heating at 150℃for 1 hour in a He gas stream (flow rate of 100 cm 3/min), at 150℃for 1 hour in a He/H 2 gas stream (flow rates of 100 cm 3/min), and at 300℃for 3 hours in a He/H 2 gas stream. The sample was cooled to room temperature in a stream of He/H 2 and then passivated in 1.5% O 2/N2 for 18 hours.
49.5 G of the reduced Pd/C-Li sample was added to 19.5 ml of 0.2MRe 2O7 and 60 ml of distilled water, and after 3 hours at room temperature, the slurry was dried at 110℃for 18 hours. After palladium addition, the Pd/Re/C-Li sample was reduced as described above and the reduced Pd/Re/C-Li catalyst was passivated in 1.5% O 2/N2 for 18 hours. The yield of the passivated reduced Pd/Re/C-Li catalyst was 49.97 g.
The catalyst of example 56 was prepared in the same manner as in example 48 except that it contained 0.5 mol% Na in addition to 3% Pd/3% Re/C. The hydrogenation reaction temperature, the reaction contact time and the experimental results of the above catalysts were all shown in Table 11 by carrying out hydrogenation in the same manner as in examples 2 to 14.
(See Table 11)
Claims (2)
1. A palladium/rhenium composite catalyst for use in the manufacture of tetrahydrofuran, 1, 4-butanediol and mixtures thereof, comprising 0.5% -10% palladium, 1% -10% rhenium (all by total weight) and balance carbon support, wherein the palladium is in the form of crystallites having an average particle size of from 10 to 25 nm and the rhenium is in the form of crystallites of a highly dispersed phase having an average particle size of less than 2.5 nm.
2. A method of making the palladium/rhenium composite catalyst of claim 1, consisting of the following steps in sequence:
(1) Impregnating a carbon support with a palladium source (i.e., palladium solution);
(2) Removing the solvent and heating the palladium-impregnated carbon under reducing conditions at a temperature of 150 ℃ to 550 ℃;
(3) Coating a rhenium source (i.e., a solution of rhenium) on the palladium-impregnated carbon;
(4) Removing the solvent;
(5) And (3) heating the composite catalyst obtained in the step (4) under the reducing condition at the temperature of 150-550 ℃.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN85101672.3A CN1004791B (en) | 1983-12-22 | 1985-04-01 | Palladium/rhenium hydrogenation catalyst and method for producing same |
| CN 88104938 CN1021224C (en) | 1985-04-01 | 1988-08-06 | Process for making tetrahydrofuran and 1,4-butanediol using pd/re hydrogenation catalyst |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/564,372 US4550185A (en) | 1983-12-22 | 1983-12-22 | Process for making tetrahydrofuran and 1,4-butanediol using Pd/Re hydrogenation catalyst |
| CN85101672.3A CN1004791B (en) | 1983-12-22 | 1985-04-01 | Palladium/rhenium hydrogenation catalyst and method for producing same |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 88104938 Division CN1021224C (en) | 1985-04-01 | 1988-08-06 | Process for making tetrahydrofuran and 1,4-butanediol using pd/re hydrogenation catalyst |
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| Publication Number | Publication Date |
|---|---|
| CN85101672A CN85101672A (en) | 1987-01-24 |
| CN1004791B true CN1004791B (en) | 1989-07-19 |
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| CN85101672.3A Expired CN1004791B (en) | 1983-12-22 | 1985-04-01 | Palladium/rhenium hydrogenation catalyst and method for producing same |
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| US7019155B2 (en) * | 2001-11-13 | 2006-03-28 | Invista North America S.A.R.L. | Hydrogenation of tetrahydroxybutane to tetrahydrofuran |
| BR112017011750A2 (en) * | 2014-12-04 | 2017-12-26 | Shell Int Research | process for the production of 1,4-butanediol and tetrahydrofuran from furan |
| CN113304747B (en) * | 2021-05-07 | 2022-07-12 | 万华化学集团股份有限公司 | Catalyst for preparing 2-methylpyridine, preparation method and method for preparing 2-methylpyridine by using same |
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