WO2016101822A1 - Copper-based catalyst and method for preparing same - Google Patents

Abstract

The present invention relates to a copper-based catalyst and a method for preparing same. The catalyst contains a silicon dioxide carrier and a copper oxide active component loaded on the carrier, where the catalyst is prepared by using a method comprising the following steps: (1) adding a silicon source to deionized water, and then adjust the pH value to 6.5 to 12 by using aqueous ammonia, to obtain a sol mixture; (2) mixing the sol mixture obtained in Step (1) and an ammoniacal copper complex solution and then performing ammonia distillation, to obtain a viscous material; and (3) sequentially performing primary drying, washing, secondary drying, and roasting on the viscous material obtained in Step (2). The catalyst provided in the present invention can reach a balance between a high conversion rate and selectivity in a process of preparing ethylene glycol by using oxolate, and has low reaction temperature, a low hydrogen/ester molar ratio, and a large liquid hourly space velocity.

Description

Copper-based catalyst and preparation method thereof Technical field

The present invention relates to a copper-based catalyst and a process for the preparation thereof.

Background technique

Ethylene glycol is an important petrochemical basic organic raw material. It is mainly used in the manufacture of polyester fiber, antifreeze, nonionic surfactant, ethanolamine and explosive, and can also be directly used as a solvent. In addition, it has a wide range of uses in the tobacco industry, the textile industry and the cosmetics industry.

Most of the existing ethylene glycol production processes use petroleum routes, that is, ethylene oxide is first produced by direct oxidation, and ethylene glycol is obtained by liquid phase catalysis or non-catalytic hydration. The reaction route is disclosed in Chinese Patent Application No. 01212038.2, U.S. Patent No. 5,847,653, and Japanese Patent No. 82,106,631. These methods have the disadvantages of long production process, high equipment required, and high energy consumption, resulting in high production cost of ethylene glycol.

In the late 1970s, LRJehner et al. first proposed a technical route for the gas phase hydrogenation of oxalate to produce ethylene glycol in Japanese Patent 5,323,101, 5,542,971; in 1985, Haruhiko Miyazaki et al., in US Pat. No. 4,551,565, discloses CuMo _k Ba _p O _x catalysts. The catalyst can completely convert diethyl oxalate at a reaction condition of 0.1 MPa, 177 ° C, a hydrogen ester ratio of 200 and a liquid hourly space velocity of about 0.036 g/g cat·h, and the ethylene glycol selectivity is 97.7%. A disadvantage of the catalyst is that the reactive hydrogen ester is relatively high and the applicable liquid hourly space velocity is low (about 0.036 g/g cat·h). A copper-based catalyst prepared by a copper ammonia silica gel method is disclosed in U.S. Patent Nos. 4,585,890 and 4,440, 873, in the reaction of diethyl oxalate to produce ethylene glycol at a reaction temperature of 188 ° C, a reaction pressure of 0.05 MPa, and a liquid hourly space. When the rate is 0.024g/g cat·h and the hydrogen ester ratio is 300, the conversion rate of diethyl oxalate is 100%, and the selectivity of ethylene glycol is 99.5%. When the other reaction conditions are unchanged, the reaction temperature is changed. When the ratio of 215 ° C and hydrogen ester ratio is changed to 50, the conversion rate of diethyl oxalate is 98%, and the selectivity of ethylene glycol is decreased to 87%. It can be seen that the catalyst has a suitable liquid hourly space velocity in order to achieve suitable ethylene glycol selectivity. (0.024 g/g cat·h only) is too low and the hydrogen ester ratio is high.

The production of ethylene glycol by hydrogenation of oxalate will produce by-products of polyhydric alcohols. Even if the content of such by-products is very low (0.1% by weight in the product), the quality of the product will be seriously affected. In addition, it is difficult to separate such by-products from the reaction product, and the energy required for separation is large. European Patent 0 060 787 reports a catalyst in which the mass fraction of such by-products in the product is about 1% with precise control of the reaction conditions, but the disadvantage of this patent is that it requires the addition of highly toxic Cr elements in the catalyst used. Moreover, the reaction conditions are harsh and difficult to industrialize. In 1985, Koichi Hirai reported a Cu/NH ₃ -Si catalyst without Cr added at an experimental condition of 220 ° C, 2 MPa, liquid hourly space velocity of 0.92 g/mL·h, and hydrogen ester ratio of 90. The conversion rate of dimethyl oxalate is 99.9%, and the selectivity of ethylene glycol is 90.4%. However, the catalyst has a high reaction temperature, and the copper crystal grains tend to grow, which is liable to cause side reactions such as hydrogenation.

In 1986, ARCO Company of the United States used Cu-Cr catalyst to convert diethyl oxalate into a catalyst with a catalyst loading of 100 mL, a temperature of 220 ° C, 3.0 MPa, a liquid hourly space velocity of 0.92 g/mL·h, and a hydrogen ester ratio of 100. Ethylene glycol, the conversion rate of diethyl oxalate in the reaction was 99.9%, the yield of ethylene glycol was 95%, and the catalyst was operated for a maximum of 466 hours. In the early 1990s, the Fujian Institute of Physical and Cultural Sciences of the Chinese Academy of Sciences completed the 200 mL mold test of hydrogenation of ethylene oxalate to ethylene glycol. Among them, using Ec-13 copper-chromium catalyst, under the reaction conditions of 0.6MPa-3.0MPa, 205°C-240°C, liquid hourly space velocity 0.327g/g cat·h, and hydrogen ester ratio of 100, the operation was 1134h, and the space-time yield was 142g/ l·h, the conversion rate of diethyl oxalate was 99.9%, and the yield of ethylene glycol was 95%. However, these catalysts all have the disadvantages of high reaction temperature and high hydrogen to ester ratio in the reaction.

Based on the current state of the art, it is desirable to find a high oxalate conversion and ethylene glycol selectivity in the reaction process for the conversion of ethylene glycol from oxalate. A copper-based catalyst having a low reaction temperature, a low hydrogen ester ratio, and a large liquid hourly space velocity, and a preparation method thereof.

Summary of the invention

It is an object of the present invention to provide a copper-based catalyst which overcomes the above disadvantages of the prior art and a process for the preparation thereof.

The present invention provides a copper-based catalyst comprising a silica support and a copper oxide active component supported on the support, wherein the catalyst is prepared by a process comprising the steps of:

(1) Add the silicon source to the deionized water, and then adjust the pH to 6.5-12 with ammonia water to obtain Sol mixture

(2) mixing the sol mixture obtained in the step (1) with a copper ammonia complex solution, and then steaming the ammonia to obtain a viscous material;

(3) The viscous material obtained in the step (2) is sequentially subjected to first drying, washing, second drying, and baking.

The invention also provides a preparation method of a copper-based catalyst, the method comprising the following steps:

(1) adding a silicon source to deionized water, and then adjusting the pH to 6.5-12 with ammonia water to obtain a sol mixture;

(2) mixing the sol mixture obtained in the step (1) with a copper ammonia complex solution, and then steaming the ammonia to obtain a viscous material;

(3) The viscous material obtained in the step (2) is sequentially subjected to first drying, washing, second drying, and baking.

Compared with the existing copper-based catalyst, the catalyst provided by the invention has a remarkable improvement in the selectivity and conversion rate of the catalyst in the preparation of ethylene glycol from the hydrogenation of oxalate, and the reaction temperature is made during the reaction. Low, low hydrogen ester ratio, high liquid hourly space velocity, and high purity of the obtained product ethylene glycol.

detailed description

The present invention provides a copper-based catalyst comprising a silica support and a copper oxide active component supported on the support, wherein the catalyst is prepared by a process comprising the steps of:

(1) adding a silicon source to deionized water, and then adjusting the pH to 6.5-12 with ammonia water to obtain a sol mixture;

(2) mixing the sol mixture obtained in the step (1) with a copper ammonia complex solution, and then steaming the ammonia to obtain a viscous material;

(3) The viscous material obtained in the step (2) is sequentially subjected to first drying, washing, second drying, and baking.

According to the present invention, various silicon sources used in the field of catalysts can be used in the present invention. However, the inventors of the present invention have found that when the silicon source is at least one of silicate, silica or silica sol, The performance of the obtained catalyst was remarkably better, and the by-product in the obtained ethylene glycol was remarkably reduced in the reaction for the conversion of oxalate to ethylene glycol. Accordingly, it is preferred in the present invention that the source of silicon be at least one of silicate, silica or silica sol, and it is especially preferred that the source of silicon is silica. In the present invention, the silicate may be various silicates, for example, methyl orthosilicate, ethyl orthosilicate, propyl orthosilicate, isopropyl orthosilicate, butyl orthosilicate And isobutyl orthosilicate; methyl metasilicate, ethyl metasilicate, propyl metasilicate, isopropyl metasilicate, butyl metasilicate and isobutyl metasilicate, preferably silicate Ethyl orthosilicate. The invention has no special requirement for the model selection of white carbon black. Various white carbon blacks in the prior art can be used in the invention, and the model of white carbon black is preferably a gas phase black carbon black A380 (for example, purchased from EVONIK-degussa, Germany). (Evonik-Degussa)), fumed silica A200 (for example, purchased from EVONIK-degussa, Germany) or white carbon black R972 (for example, from Cabot).

In the present invention, the manner in which a silicon source is added to deionized water is well known to those skilled in the art. For example, a silicon source can be added to deionized water at room temperature (about 5 to about 45 ° C) and stirred to make silicon. The source hydrolyzes and/or swells to form a gelatinous material. The present invention has no particular requirement for the amount of deionized water used in the step (1) for hydrolyzing and/or swelling the silicon source to form a gelatinous substance. Preferably, the amount of deionized water is 100 based on the weight of the silicon source. - 2000% by weight, preferably 150-1500% by weight.

After the silicon source is added to the deionized water, pH adjustment is one of the keys to achieving the present invention. Although the general idea of synthesizing a catalyst is that the silicon source is hydrolyzed and/or swollen in deionized water to form a gel-like substance without pH adjustment, the prepared catalyst has better catalytic performance, but the inventors are in the course of research. It has been found that when preparing the copper-based catalyst of the present invention, a sol mixture obtained by adjusting the pH to 6.5-12 by adding ammonia water after hydrolyzing and/or swelling the silicon source in deionized water to obtain a gel-like substance can obtain better stability. The performance of the resulting catalyst is made better. In order to obtain better catalyst performance, it is further preferred to add ammonia water to adjust the pH to 7-12.

The time of the present invention for adding a silicon source to deionized water and then adding ammonia water is not particularly limited. That is, the addition of ammonia water may be completely formed into a gel-like substance by adding a silicon source to the deionized water, or may be added when the silicon source is added to the deionized water to partially form a gel-like substance.

The present invention is directed to hydrolyzing and/or swelling a silicon source in deionized water to form a partial or complete condensation. After the gelatinous substance, the concentration of the aqueous ammonia used for pH adjustment is not particularly limited, and for example, the concentration of the aqueous ammonia may be 10 to 30% by weight, preferably 18 to 28% by weight.

In order to make the charge distribution of the ammonia-modified sol mixture more stable and uniform, it is preferred that the addition of all the materials in the step (1) is carried out under stirring such as mechanical stirring to ensure a stable and uniform charge distribution. Specifically, the stirring time may be 5 to 120 minutes, and the stirring speed may be 50 to 600 rpm to make the obtained sol mixture sufficiently stable.

The copper ammonia complex solution of the present invention can be prepared by using the existing method for preparing a copper ammonia complex solution, as long as the prepared pH value satisfies the requirements of the present invention, for example, the concentration can be 18-28% by weight. The ammonia water is contacted with a water-soluble copper salt. The water-soluble copper salt may be various water-soluble copper salts, and may be, for example, copper nitrate, copper sulfate, copper acetate, copper oxalate and/or copper halide, wherein the copper halide may be selected from copper chloride and copper bromide, preferably The water-soluble copper salt is copper nitrate and/or copper acetate. The ratio of the water-soluble copper salt to the aqueous ammonia may be such that the molar ratio of ammonia to copper element in the obtained copper ammonia complex solution is from 4 to 100, preferably from 4 to 90.

Although the object of the present invention can be achieved by using a copper-ammonium complex solution having a pH of 7-14, the inventors of the present invention found that when the pH of the copper-ammonium complex solution is from 10 to 13.5, the synthesized catalyst is apparent. Better catalytic performance.

According to the present invention, the amount of the copper ammonia complex solution in the step (2) can be appropriately selected depending on the intended catalyst composition. Preferably, the ratio of the amount of the added sol mixture to the copper ammonia complex solution is such that the active component is 6 to 70% by weight based on the total weight of the catalyst, and the carrier content is 30. -94% by weight.

The feeding method of the present invention for mixing the sol mixture obtained in the step (1) with the copper ammonia complex solution in the step (2) is not particularly limited, and may include one feeding, that is, one material is added to another material at a time. Then, the manner of mixing, and the dropwise addition, the addition method includes positive addition, reverse addition, and parallel addition. The one-time feeding can be carried out under stirring such as mechanical stirring, the stirring speed can be 50-600 rpm, and the stirring time can be, for example, 15-240 minutes.

The conditions of the ammonia distillation in the step (2) of the present invention are not particularly limited, and the conditions for the ammonia distillation include: a temperature of 50 to 130 ° C; a time of 0.5 to 50 hours; further preferably a temperature of 60 to 120 ° C; It is 1-48 hours.

The steamed ammonia can be stirred under mechanical stirring, and the stirring speed can be 300-600 rpm. The stirring time can be, for example, 2-48 hours.

The first drying in step (3) is another key to achieving the present invention. Although the general idea of synthesizing a copper-based catalyst is to carry out heating and evaporation after mixing the sol mixture and the copper-ammonium complex solution, then filtering, washing, and drying and calcining the solid obtained after filtration and washing. The inventors of the present invention have found that the viscous material obtained in the step (2) is directly subjected to the first drying and then subjected to deionized water washing, second drying and calcination without filtration and without washing, and the prepared catalyst has more catalyst. Good catalytic performance.

The first drying condition in the step (3) of the present invention is not particularly limited. Preferably, the first drying condition comprises: a drying temperature of 50 to 160 ° C; and a drying time of 3 to 24 hours. It is further preferred that the drying time is from 60 to 150 ° C; the drying time is from 6 to 20 hours.

The method of the first drying in the step (3) of the present invention is not particularly limited, and for example, ordinary heat drying, microwave drying, and spray drying, preferably spray drying, may be employed.

The washing, the second drying and the calcination of the step (3) can be carried out by various washing, drying and calcining methods in the prior art. For example, the second drying temperature can be 60-150 ° C, and the drying time can be 2 -24 hours. The second drying temperature is preferably from 60 to 120 ° C, and the drying time is preferably from 6 to 12 hours.

The calcination temperature may be from 250 to 1000 ° C, the calcination time may be from 1 to 12 hours, the calcination temperature is preferably from 300 to 800 ° C, and the calcination time is from 2 to 10 hours. It is further preferred that the calcination temperature is from 300 to 700 ° C and the calcination time is from 4 to 6 hours.

In the present invention, the material which is passed through the second drying can be molded in a conventional manner before firing. The molding method may be, for example, tablet molding, ball molding, and extrusion molding. The conditions for the deionized water washing in the present invention are not particularly limited as long as the material obtained after the first drying is washed until the washing liquid is neutral.

In the present invention, it is preferred that the active component is contained in an amount of from 6 to 70% by weight based on the total weight of the catalyst, and the content of the carrier is from 30 to 94% by weight; more preferably, based on the total weight of the catalyst, to oxidize The content of the active component of the copper is from 22 to 45% by weight, and the content of the carrier is from 55 to 78% by weight. In the present invention, the total weight of the catalyst refers to the total weight of the active component oxide and the carrier.

In the present invention, the catalyst thus obtained may have a specific surface area of from 50 to 600 m ² /g, preferably from 250 to 450 m ² /g, further preferably from 280 to 360 m ² /g. The catalyst may have a pore volume of from 0.1 to 2.0 cm ³ /g, preferably from 0.3 to 1.0 cm ³ /g, further preferably from 0.5 to 0.85 cm ³ /g.

The invention also provides a preparation method of a copper-based catalyst, the method comprising the following steps:

(1) adding a silicon source to deionized water, and then adjusting the pH to 6.5-12 with ammonia water to obtain a sol mixture;

(2) mixing the sol mixture obtained in the step (1) with a copper ammonia complex solution, and then steaming the ammonia to obtain a viscous material;

(3) The viscous material obtained in the step (2) is sequentially subjected to first drying, washing, second drying, and baking.

According to the production method of the present invention, each raw material is used in an amount such that the active component is 6 to 70% by weight based on the total weight of the catalyst, and the carrier is contained in an amount of 30 to 94% by weight.

In a preferred embodiment, the method for preparing a copper-based catalyst of the present invention may comprise the following steps:

(1) Adding a silicon source to deionized water at room temperature (about 25 ° C) and stirring to form a gelatinous substance, adjusting the pH value between 6.5 and 12 with ammonia water, stirring speed of 50-600 rpm, stirring time of 5 - 120 minutes to obtain a sol mixture;

(2) Dissolving copper salt in aqueous ammonia at room temperature (about 25 ° C) and stirring to prepare a copper ammonia complex solution, the molar ratio of ammonia to copper in the solution is 4-100; pH is 7-14, The stirring speed is 50-600 rpm; the stirring time is 5-120 minutes;

(3) mixing the sol mixture obtained in the step (1) with the copper ammonia complex solution prepared in the step (2) at a normal temperature (about 25 ° C) and stirring, the stirring speed is 50-600 rpm, and the stirring time is 15-240. Minutes to get a mixed solution;

(4) stirring the mixed solution obtained in the step (3) at a stirring temperature of 300-600 rpm at a temperature of 50-130 ° C for 2 to 48 hours to form a viscous material;

(5) drying the viscous material at a temperature of 50-160 ° C for 3-24 hours to obtain a dry material;

(6) The dried material is washed with deionized water, dried at a temperature of 60-150 ° C for 2-24 hours, and after tableting, calcined at 250-1000 ° C for 1-12 hours to obtain the present invention. Catalyst.

Example

The invention will now be described in more detail by way of examples. The examples are intended to be merely illustrative of the preferred embodiments of the invention, and are not intended to limit the scope of the invention.

Elemental analysis (X-ray fluorescence analysis) was performed on an Axios-Advanced fluorescence analyzer from PANalytical B V, the Netherlands.

UV transmittance and aldehyde content measurements were performed on a TU-1900 dual-beam UV-Vis spectrophotometer from Beijing General Instrument Co., Ltd. The method for determining the aldehyde content is determined by reference to the national standard GB/T14571.3-2008 for the determination of aldehyde content in industrial ethylene glycol_spectrophotometry.

The specific surface area and pore volume of the catalyst were determined by AMD 2020M+C physicochemical adsorption meter from American Micron.

Example 1

(1) At room temperature (25 ° C) and stirring speed of 350 rpm, 50 g of tetraethyl orthosilicate was added to 400 mL of deionized water, then aqueous ammonia (concentration of 25% by weight) was added to adjust the pH to 9.0, and the stirring time was 30 minutes. Obtaining a sol mixture;

(2) at room temperature (25 ℃) copper nitrate _{44g (Cu (NO 3) 2} · 3H 2 O, hereinafter the same) was dissolved in aqueous ammonia (concentration 25 wt%) of copper ammine complex solution 330mL formulated in solution The molar ratio of ammonia to copper element is 24, the pH value is 12, and the stirring speed is 300 rpm for 30 minutes to obtain a copper ammonia complex solution;

(3) mixing the sol mixture obtained in the step (1) and the copper ammonia complex solution obtained in the step (2) at a normal temperature (25 ° C) with stirring at a stirring speed of 350 rpm, a stirring time of 120 minutes; °C, stirring at a stirring speed of 350 rpm for 6 hours to carry out ammonia distillation to form a viscous material;

(4) The viscous material is first dried at a temperature of 120 ° C for 12 hours to obtain a dry material;

(5) The dried material obtained in the step (4) is washed with deionized water until the washing liquid is neutral, and the second drying is carried out at 120 ° C for 12 hours, and after calcination, it is calcined at 500 ° C for 6 hours to obtain a catalyst Cu. /SiO ₂ (A) 32 g.

The obtained catalyst was found to have a specific surface area of 304 m ² /g, a pore volume of 0.53 cm ³ /g, and a copper element content of 36% by weight in the catalyst. The specific properties of the obtained catalyst are shown in Table 1.

Comparative example 1

The procedure of Example 1 was followed, except that the step of adjusting the pH to 9 with aqueous ammonia (concentration of ammonia water of 25% by weight) in the step (1) was omitted, and a catalyst was obtained. The specific properties of the obtained catalyst are shown in Table 1.

Comparative example 2

Consistent with the method of Example 1, except that the first drying in step (4) was omitted and washed directly with deionized water until the washing liquid was neutral to obtain a catalyst. The specific properties of the obtained catalyst are shown in Table 1. Comparative example 3

Consistent with the method of Example 1, except that the step of adjusting the pH to 9 with ammonia water (concentration of ammonia water of 25% by weight) and the first drying in step (4) in step (1), directly using deionization The water was washed until the washing liquid was neutral to obtain a catalyst. The specific properties of the obtained catalyst are shown in Table 1.

Example 2

(1) 200g silica sol (type JN25, silica solid content 25% by weight, purchased from Qingdao Ocean Chemical Co., Ltd.) was added to 100mL of deionized water at room temperature (25 ° C) and stirring speed of 600 rpm, using ammonia water (concentration) 25% by weight) to adjust the pH to 12, the stirring time is 5 minutes, to obtain a sol mixture;

(2) Preparing 1125 mL of copper ammonia complex solution by dissolving 44 g of copper nitrate in ammonia water (concentration: 25% by weight) at normal temperature (25 ° C), the molar ratio of ammonia to copper in the solution is 90, and the pH is 14. Stirring at a stirring speed of 50 rpm for 5 minutes to obtain a copper ammonia complex solution;

(3) mixing the sol mixture obtained in the step (1) and the copper ammonia complex solution obtained in the step (2) at a normal temperature (25 ° C) under stirring, stirring at 600 rpm, stirring time for 15 minutes; then at a temperature of 60 °C, stirring at a stirring speed of 600 rpm for 48 hours to carry out ammonia distillation to form a viscous material;

(4) The viscous material is first dried at a temperature of 80 ° C for 20 hours to obtain a dry material;

(5) The dried material is washed with deionized water until the washing liquid is neutral, and the second drying is carried out at 120 ° C for 2 hours, and after calcination, it is calcined at 300 ° C for 4 hours to obtain a catalyst Cu/SiO ₂ (B). 64g.

The obtained catalyst was found to have a specific surface area of 302 m ² /g, a pore volume of 0.51 cm ³ /g, and a copper element content of 18% by weight in the catalyst. The specific properties of the obtained catalyst are shown in Table 1.

Example 3

(1) 50 g of white carbon black (Cabot R972) was added to 600 mL of deionized water at room temperature (25 ° C) and a stirring speed of 50 rpm, and the pH was adjusted to 7.0 with ammonia water (concentration of ammonia water of 25% by weight). Stirring time is 120 minutes to obtain a sol mixture;

(2) 430 g of copper ammonia complex solution was prepared by dissolving 254 g of copper nitrate in ammonia (25% by weight of ammonia water) at normal temperature (25 ° C), and the molar ratio of ammonia to copper in the solution was 4, and the pH was 10, stirring at a stirring speed of 600 rpm for 120 minutes to obtain a copper ammonia complex solution;

(3) mixing the sol mixture obtained in the step (1) and the copper ammonia complex solution obtained in the step (2) at a normal temperature (25 ° C) with stirring, stirring speed is 600 rpm, stirring time is 120 minutes; then at a temperature of 120 °C, stirring at a stirring speed of 350 rpm for 12 hours to carry out ammonia distillation to form a viscous material;

(4) The viscous material is first dried at a temperature of 150 ° C for 3 hours to obtain a dry material;

(5) The dried material obtained in the step (4) is washed with deionized water until the washing liquid is neutral, and the second drying is carried out at 90 ° C for 4 hours, and after calcination, it is calcined at 400 ° C for 4 hours to obtain a catalyst Cu. / SiO ₂ (C) 133 g.

The obtained catalyst was determined to have a specific surface area of 410 m ² /g, a pore volume of 0.71 cm ³ /g, and a copper element content of 50% by weight in the catalyst. The specific properties of the obtained catalyst are shown in Table 1.

Example 4

(1) At room temperature (25 ° C) and stirring speed of 350 rpm, 50 g of fumed silica (purchased from EVONIK-degussa, Germany, model A380) was added to 200 mL of deionized water with ammonia water (ammonia concentration of 18 weight) %) adjusting the pH to 10.0 and stirring for 60 minutes to obtain a sol mixture;

(2) Dissolving 16.3g of copper acetate (Cu(CH ₃ OO) ₂ .H ₂ O) into ammonia water (concentration of ammonia water: 18% by weight) at normal temperature (25 ° C) to prepare 110 mL of copper ammonia complex solution, solution The molar ratio of medium ammonia to copper element is 12, the pH value is 12.5, and the stirring speed is 500 rpm for 120 minutes to obtain a copper ammonia complex solution;

(3) mixing the sol mixture obtained in the step (1) and the copper ammonia complex solution obtained in the step (2) at a normal temperature (25 ° C) with stirring, stirring speed is 600 rpm, stirring time is 120 minutes; then at a temperature of 120 °C, stirring at 500 rpm for 1 hour to carry out ammonia distillation to form a viscous material;

(4) The viscous material is first dried at a temperature of 120 ° C for 6 hours to obtain a dry material;

(5) The dried material obtained in the step (4) is washed with deionized water until the washing liquid is neutral, and the second drying is carried out at 90 ° C for 6 hours, and after calcination, it is calcined at 700 ° C for 4 hours to obtain a catalyst Cu. / SiO ₂ (D) 52 g.

The obtained catalyst was determined to have a specific surface area of 360 m ² /g, a pore volume of 0.82 cm ³ /g, and a content of copper element in the catalyst of 10% by weight. The specific properties of the obtained catalyst are shown in Table 1.

Example 5

(1) 50 g of fumed silica (purchased from EVONIK-degussa, Germany; model A200) was added to 400 mL of deionized water at room temperature (25 ° C) and a stirring speed of 350 rpm, using ammonia water (ammonia concentration of 25 weight) %) adjusting the pH to 10.0 and stirring for 5 minutes to obtain a sol mixture;

(2) Dissolving 44 g of copper nitrate in ammonia (25% by weight of ammonia) at room temperature (25 ° C) to prepare 330 mL of copper ammonia complex solution, the molar ratio of ammonia to copper in the solution is 24, pH value Stirring at 13.5, stirring speed of 300 rpm for 5 minutes to obtain a copper ammonia complex solution;

(3) mixing the sol mixture obtained in the step (1) and the copper ammonia complex solution obtained in the step (2) at a normal temperature (25 ° C) with stirring, stirring speed is 300 rpm, stirring time is 5 minutes; then at a temperature of 100 °C, stirring at 300 rpm for 2 hours to dilute ammonia to form a viscous material;

(4) drying the viscous material at a temperature of 120 ° C for 10 hours to obtain a dry material;

(5) The dried material obtained in the step (4) is washed with deionized water until the washing liquid is neutral, and the second drying is carried out at 120 ° C for 10 hours, and after calcination, it is calcined at 750 ° C for 4 hours to obtain a catalyst Cu. /SiO ₂ (E) 64 g.

The obtained catalyst was found to have a specific surface area of 284 m ² /g, a pore volume of 0.85 cm ³ /g, and a copper element content of 18% by weight in the catalyst. The specific properties of the obtained catalyst are shown in Table 1.

Example 6

(1) At room temperature (25 ° C) and stirring speed of 600 rpm, 50 g of fumed silica (purchased from Germany EVONIK-degussa model A380) was added to 400 mL of deionized water with ammonia water (concentration of ammonia was 28% by weight) Adjusting the pH to 7.0 and stirring for 20 minutes to obtain a sol mixture;

(2) Dissolving 110 g of copper nitrate in ammonia water (concentration of ammonia water: 28% by weight) at normal temperature (25 ° C) to prepare 400 mL of copper ammonia complex solution, the molar ratio of ammonia to copper in the solution is 12, and the pH value is 12.5, stirring at a stirring speed of 500 rpm for 60 minutes to obtain a copper ammonia complex solution;

(3) mixing the sol mixture obtained in the step (1) and the copper ammonia complex solution obtained in the step (2) at a normal temperature (25 ° C) with stirring at a stirring speed of 500 rpm, a stirring time of 30 minutes; °C, stirring at 500 rpm for 4 hours to dilute ammonia to form a viscous material;

(4) The viscous material is first dried at a temperature of 80 ° C for 20 hours to obtain a dry material;

(5) The dried material obtained in the step (4) is washed with deionized water until the washing liquid is neutral, and the second drying is carried out at 60 ° C for 15 hours, and after calcination, it is calcined at 400 ° C for 6 hours to obtain a catalyst Cu. / SiO ₂ (F) 96 g.

The obtained catalyst was found to have a specific surface area of 350 m ² /g, a pore volume of 0.76 cm ³ /g, and a copper element content of 30% by weight in the catalyst. The specific properties of the obtained catalyst are shown in Table 1.

Table 1 Catalyst characterization test results

Catalyst source	Specific surface area / (m 2 /g)	Hole capacity / (cm 3 /g)
Example 1	304	0.53
Example 2	302	0.51
Example 3	410	0.71
Example 4	360	0.82
Example 5	284	0.85
Example 6	350	0.76
Comparative example 1	230	1.1
Comparative example 2	260	0.46
Comparative example 3	263	0.87

Catalyst performance test

The catalysts obtained in Examples 1-6 and Comparative Examples 1-3 were crushed and screened to 40-60 mesh, and passed through 300 ° C. After pure hydrogen reduction for 6 hours, the reaction was adjusted to the reaction process conditions.

Test Examples 1-6

The catalyst prepared in Example 1-6 after the above treatment was placed in a micro fixed bed continuous flow reactor, the inner diameter of the reactor was 10 mm, and the thermocouple sleeve was installed inside the reactor, and the catalyst loading amount was 2 g, and the raw material gas was from top to bottom. Pass through the catalyst bed.

The operating conditions of the reaction of hydrogenation of dimethyl oxalate to ethylene glycol are as follows: reaction temperature 170 ° C, reaction pressure 2.8 MPa, catalyst loading (liquid hourly space velocity of reaction raw material dimethyl oxalate) 2.1 g / g cat.h, hydrogen / dimethyl oxalate = 60 (molar ratio). The reaction results are shown in Table 2. The obtained reaction product was taken out from the bottom of the reactor, and distilled under reduced pressure of 12 kPa and 150 ° C using a distillation column having a theoretical number of plates of 45 to obtain a product ethylene glycol. The properties of ethylene glycol are shown in Table 3.

Test Example 7-12

The same as Test Examples 1-6 except that dimethyl oxalate was changed to diethyl oxalate. The reaction results are shown in Table 2. The obtained reaction product was taken out from the bottom of the reactor, and distilled under reduced pressure of 12 kPa and 150 ° C using a distillation column having a theoretical number of plates of 45 to obtain a product ethylene glycol. The properties of ethylene glycol are shown in Table 3.

Test Example 13-18

The catalysts of Examples 1-6 treated as above were placed in a micro fixed bed continuous flow reactor with an inner diameter of 10 mm, a thermowell inside the reactor, and a catalyst loading of 2 g. The raw material gas passed through from top to bottom. Catalyst bed.

The reaction conditions for hydrogenation of dimethyl oxalate to ethylene glycol are as follows: reaction temperature 160 ° C, reaction pressure 8.0 MPa, catalyst loading (liquid hourly space velocity of reaction raw material dimethyl oxalate) 0.5 g / g cat.h, hydrogen / oxalic acid Dimethyl ester = 200 (molar ratio). The reaction results are shown in Table 2. The obtained reaction product was taken out from the bottom of the reactor, and distilled under reduced pressure of 12 kPa and 150 ° C using a distillation column having a theoretical number of plates of 45 to obtain a product ethylene glycol. The properties of ethylene glycol are shown in Table 3.

Test Example 19-24

The same as Test Examples 13-18, except that dimethyl oxalate was changed to diethyl oxalate. The reaction results are shown in Table 2. The obtained reaction product was taken out from the bottom of the reactor by a distillation column having a theoretical number of plates of 45, and distilled under a reduced pressure of 12 kPa at 150 ° C to obtain a product ethylene glycol. The properties of ethylene glycol are shown in Table 3.

Test Example 25-30

The catalysts of Preparation Examples 1-6 after the above treatment were placed in a micro fixed bed continuous flow reactor, the inner diameter of the reactor was 10 mm, and the thermocouple sleeve was installed inside the reactor, and the catalyst loading amount was 2 g, and the raw material gas was from top to bottom. Pass through the catalyst bed.

The operating conditions for the hydrogenation of dimethyl oxalate to ethylene glycol are as follows: reaction temperature 240 ° C, reaction pressure 1.5 MPa, catalyst loading (liquid hourly space velocity of reaction raw material dimethyl oxalate) 8 g / g cat.h, hydrogen / Dimethyl oxalate = 150 (molar ratio). The reaction results are shown in Table 2. The obtained reaction product was taken out from the bottom of the reactor, and distilled under reduced pressure of 12 kPa and 150 ° C using a distillation column having a theoretical number of plates of 45 to obtain a product ethylene glycol. The properties of ethylene glycol are shown in Table 3.

Test Examples 31-36

The same as Test Examples 25-30 except that dimethyl oxalate was replaced with diethyl oxalate. The reaction results are shown in Table 2. The obtained reaction product was taken out from the bottom of the reactor, and distilled under reduced pressure of 12 kPa and 150 ° C using a distillation column having a theoretical number of plates of 45 to obtain a product ethylene glycol. The properties of ethylene glycol are shown in Table 3.

Test comparison 1-3

The catalyst prepared in the above Comparative Example 1-3 was placed in a micro fixed bed continuous flow reactor, the inner diameter of the reactor was 10 mm, and the thermocouple sleeve was installed inside the reactor, and the catalyst loading amount was 2 g, and the raw material gas was from top to bottom. Pass through the catalyst bed.

The reaction conditions for hydrogenation of dimethyl oxalate to ethylene glycol are as follows: reaction temperature 200 ° C, reaction pressure 2.8 MPa, catalyst loading (liquid hourly space velocity of reaction raw material dimethyl oxalate) 2.1 g / g cat.h, hydrogen / oxalic acid Dimethyl ester = 100 (molar ratio). The reaction results are shown in Table 2. The obtained reaction product was taken out from the bottom of the reactor, using a distillation column having a theoretical number of plates of 45, at a reduced pressure of 12 kPa and Distillation at 150 ° C gave the product ethylene glycol. The properties of ethylene glycol are shown in Table 3.

Test comparison 4-6

The same procedure as in Comparative Example 1-3 was carried out except that dimethyl oxalate was replaced with diethyl oxalate. The reaction results are shown in Table 2. The obtained reaction product was taken out from the bottom of the reactor, and distilled under reduced pressure of 12 kPa and 150 ° C using a distillation column having a theoretical number of plates of 45 to obtain a product ethylene glycol. The properties of ethylene glycol are shown in Table 3.

Test Comparative Example 7-9

The catalyst prepared in the above Comparative Example 1-3 was placed in a micro fixed bed continuous flow reactor, the inner diameter of the reactor was 10 mm, and the thermocouple sleeve was installed inside the reactor, and the catalyst loading amount was 2 g, and the raw material gas was from top to bottom. Pass through the catalyst bed.

The reaction conditions for hydrogenation of dimethyl oxalate to ethylene glycol are as follows: reaction temperature 160 ° C, reaction pressure 8.0 MPa, catalyst loading (liquid hourly space velocity of reaction raw material dimethyl oxalate) 0.5 g / g cat.h, hydrogen / oxalic acid Dimethyl ester = 200 (molar ratio). The reaction results are shown in Table 2. The obtained reaction product was taken out from the bottom of the reactor, and distilled under reduced pressure of 12 kPa and 150 ° C using a distillation column having a theoretical number of plates of 45 to obtain a product ethylene glycol. The properties of ethylene glycol are shown in Table 3.

Test comparison 10-12

The test was carried out in the proportion of 7-9, except that the dimethyl oxalate was changed to diethyl oxalate. The reaction results are shown in Table 2. The obtained reaction product was taken out from the bottom of the reactor, and distilled under reduced pressure of 12 kPa and 150 ° C using a distillation column having a theoretical number of plates of 45 to obtain a product ethylene glycol. The properties of ethylene glycol are shown in Table 3.

Test comparison 13-15

The catalyst prepared in the above Comparative Example 1-3 was placed in a micro fixed bed continuous flow reactor, the inner diameter of the reactor was 10 mm, and the thermocouple sleeve was installed inside the reactor, and the catalyst loading amount was 2 g, and the raw material gas was from top to bottom. Pass through the catalyst bed.

The reaction conditions for hydrogenation of dimethyl oxalate to ethylene glycol are as follows: reaction temperature 240 ° C, reaction pressure The force was 1.5 MPa, the catalyst load (liquid hourly space velocity of the reaction raw material dimethyl oxalate) 8 g / g cat.h, hydrogen / dimethyl oxalate = 150 (molar ratio). The reaction results are shown in Table 2. The obtained reaction product was taken out from the bottom of the reactor, and distilled under reduced pressure of 12 kPa and 150 ° C using a distillation column having a theoretical number of plates of 45 to obtain a product ethylene glycol. The properties of ethylene glycol are shown in Table 3.

Test comparison 16-18

The same procedure as in Comparative Example 13-15 was carried out except that dimethyl oxalate was replaced with diethyl oxalate. The reaction results are shown in Table 2. The obtained reaction product was taken out from the bottom of the reactor, and distilled under reduced pressure of 12 kPa and 150 ° C using a distillation column having a theoretical number of plates of 45 to obtain a product ethylene glycol.

The properties of ethylene glycol are shown in Table 3.

Table 2 Reaction results of ethylene glycol prepared by different catalysts

As can be seen from Table 2, in the reaction of preparing ethylene glycol from oxalate of the present invention, the catalysts prepared in Examples 1-6 all exhibited higher oxalate conversion and ethylene glycol selectivity.

Determination of ethylene glycol performance parameters

The UV transmittance and aldehyde content of ethylene glycol were determined by TU-1900 dual-beam UV-Vis spectrophotometer from Beijing General Instrument Co., Ltd. The measurement results are shown in Table 3.

Table 3 Comparison of properties of ethylene glycol prepared by different catalysts

It can be seen from Table 3 that the ethylene glycol obtained by the hydrogenation synthesis of oxalate using the catalyst provided by the present invention exceeds the standard of the national standard ethylene glycol in the key indicators after simple rectification, and the test is synthesized in the comparative example. After the simple distillation, the obtained ethylene glycol did not reach the standard of the national standard ethylene glycol in the key indicators.

Claims (14)

1. A copper-based catalyst comprising a silica support and a copper oxide active component supported on the silica support, characterized in that the catalyst is prepared by the following method comprising the following steps:

   (1) adding a silicon source to deionized water, and then adjusting the pH to 6.5-12 with ammonia water to obtain a sol mixture;

   (2) mixing the sol mixture obtained in the step (1) with a copper ammonia complex solution, and then steaming the ammonia to obtain a viscous material;

   (3) The viscous material obtained in the step (2) is sequentially subjected to first drying, washing, second drying, and baking.
2. The catalyst according to claim 1, wherein the active component is contained in an amount of from 6 to 70% by weight based on the total weight of the catalyst, and the carrier is contained in an amount of from 30 to 94% by weight.
3. The catalyst according to claim 1, wherein the source of silicon is at least one selected from the group consisting of silicates, silica or silica sols; preferably white carbon black.
4. The catalyst according to claim 1, wherein the conditions for the ammonia distillation comprise: a temperature of 50 to 130 ° C; and a time of 0.5 to 50 hours.
5. The catalyst according to any one of claims 1 to 4, wherein the first drying condition comprises a temperature of 50 to 160 ° C; and a time of 3 to 24 hours.
6. The catalyst according to any one of claims 1 to 5, wherein the second drying condition comprises a temperature of 60 to 150 ° C; and a time of 2 to 24 hours.
7. The catalyst according to any one of claims 1 to 6, wherein the pH is adjusted to 7-12 with aqueous ammonia in the step (1).
8. A method for preparing a copper-based catalyst, the method comprising the steps of:

   (1) adding a silicon source to deionized water, and then adjusting the pH to 6.5-12 with ammonia water to obtain a sol mixture;

   (2) mixing the sol mixture obtained in the step (1) with a copper ammonia complex solution, and then steaming the ammonia to obtain a viscous material;

   (3) The viscous material obtained in the step (2) is sequentially subjected to first drying, washing, second drying, and baking.
9. The method according to claim 8, wherein each of the raw materials is used in an amount such that the active component is 6 to 70% by weight based on the total weight of the catalyst, and the carrier is contained in an amount of 30 to 94% by weight.
10. The method of claim 8 wherein said source of silicon is selected from at least one of silicate, silica or silica sol; preferably silica.
11. The method according to claim 8, wherein the conditions for the ammonia distillation comprise: a temperature of 50 to 130 ° C; and a time of 0.5 to 50 hours.
12. The method of any of claims 8-11, wherein the first drying conditions comprise: a temperature of 50-160 ° C; a time of 3-24 hours.
13. The method according to any one of claims 8 to 12, wherein the second drying condition comprises a temperature of 60 to 150 ° C; and a time of 2 to 24 hours.
14. The method according to any one of claims 8-13, wherein step (1) adjusts the pH to 7-12 with aqueous ammonia.