A catalyst for oxalate hydrogenation, preparation method and application thereof

Abstract

The present invention relates to a catalyst for oxalate hydrogenation, a preparation method and an application, and belongs to the technical field of catalyst preparation. The catalyst comprises 25-60wt% silicon oxide, 20-60wt% copper oxide, 1-50wt% titanium oxide, 0.5-2wt% magnesium oxide, and the remainder is a catalyst active component. The preparation method of the present invention first applies reactive distillation to prepare a carrier, and then uses an auxiliary agent to modify the carrier, and finally adopts a parallel flow method to load the active component to obtain a catalyst precursor, and through suction filtration, washing, extrusion, drying, and roasting, the required catalyst is obtained. The catalyst of the present invention is applied to the oxalate hydrogenation synthesis ethanol process, and the oxalate conversion rate is 100%, and the target product ethanol selectivity reaches more than 93%. After long-term start-up operation, the activity has no obvious decrease, the bed pressure drop is stable, and there is no coking and powdering phenomenon, and it has a very high application prospect and commercial value.

Description

Technical Field

[0001] The invention relates to an oxalate hydrogenation catalyst, a preparation method and an application thereof, and belongs to the technical field of catalyst preparation. Background Art

[0002] Ethanol, commonly known as alcohol, is a colorless, transparent, volatile, flammable, and slightly pungent liquid. Ethanol plays an important role in people's lives and is widely used in the production of disinfectants, beverage products, chemical raw materials, automobile fuels, preservatives, etc. At present, the main industrial synthesis processes include biomass fermentation, ethylene direct hydration, synthetic acetate and acetic acid hydrogenation, and synthetic dimethyl oxalate hydrogenation. my country is rich in coal resources. Research and development of a new process route for producing ethanol from coal-based synthesis gas can lay an important foundation for my country's sustainable development.

[0003] At present, oxalate can be selectively hydrogenated under the action of catalysts to synthesize important chemical raw materials such as ethylene glycol, methyl glycolate and ethanol. However, there are few studies on the direct synthesis of ethanol by catalytic hydrogenation of oxalate. CN113289632A and CN108236955B both disclose a method for preparing a catalyst for hydrogenation of oxalate to ethanol. The core work for high selectivity control of the target product lies in the design of the catalyst and the matching of reaction conditions.

[0004] In view of the above-mentioned defects, the present invention aims to create a catalyst for oxalate hydrogenation and a preparation method and application thereof, so as to make it more valuable for industrial utilization. Summary of the invention

[0005] To solve the above technical problems, the purpose of the present invention is to provide a catalyst for oxalate hydrogenation to ethanol, a preparation method and an application. The present invention adopts a reactive distillation method to prepare a carrier, especially a parallel flow synthesis of copper phyllosilicate and copper oxide, which can be used as a carrier and an active component and a molding agent, greatly improving the possibility and strength performance of the late catalyst extrusion molding, avoiding the high-cost and complex molding process that requires crushing and tableting, and ensuring high activity and selectivity when ethanol synthesis is started. The carrier modification is very good at adjusting the acidity and alkalinity of the catalyst after activation, which is conducive to promoting the loading of the active component and the adsorption-reaction-diffusion-coupling effect between the material and the catalyst. The parallel flow coprecipitation method of the VIII B or / and IB group active components greatly improves the dispersibility of the active component, and is used for oxalate hydrogenation to synthesize ethanol to achieve good results.

[0006] The invention discloses an oxalate hydrogenation catalyst. The carrier is prepared by reactive distillation and modified with magnesium salt. Finally, a parallel flow method is used to prepare the catalyst, which contains 25-60wt% silicon oxide, 20-40wt% copper oxide, 10-60wt% titanium oxide, 0.5-2wt% magnesium oxide, and the remainder is catalyst active components.

[0007] Furthermore, the carrier is made of silicon oxide, copper oxide and titanium oxide in a certain proportion.

[0008] Furthermore, the carrier modification component is a soluble magnesium salt, specifically one or a combination of magnesium sulfate, magnesium nitrate, magnesium chloride, magnesium acetate and magnesium carbonate, and the active component is selected from one or any several soluble metal salts in group VIB and / or IB, preferably nickel salt and / or palladium salt.

[0009] A method for preparing an oxalate hydrogenation catalyst, the specific preparation steps are:

[0010] S1. Load a certain amount of activated acidic sulfonic acid resin into a jacketed thermostatic distillation column, and add a certain amount of deionized water and urea to the bottom of the reactor;

[0011] S2, tetrabutyl titanate, tetraethyl silicate and water are mixed in proportion for standby use, and a copper salt solution and a magnesium salt solution of a certain concentration are prepared for standby use;

[0012] S3, start stirring to heat the reactor to a specified temperature, and at the same time raise the temperature of the distillation column. After the reaction conditions meet the reaction requirements, according to the material ratio and reaction time, add the two solutions of S2 to the reactor at a controlled rate. After the addition is complete, keep the temperature and continue the reaction for a period of time to obtain the carrier L;

[0013] S4, control the pH of slurry L, add the magnesium salt solution prepared in S2 dropwise, and stir for 0.5 to 2 hours after the addition is completed to obtain modified carrier B;

[0014] S5, adding a precipitant and a mixed salt solution containing a certain proportion of a dispersant to the modified carrier B slurry at the same time to carry out an active component loading reaction, and after the reaction is completed, aging to obtain a catalyst slurry J;

[0015] S6. Filter, wash, squeeze, extrude, dry and calcine the catalyst slurry J to obtain the finished catalyst product LBJ.

[0016] Furthermore, the mixing in proportion described in S2 refers to a water-ester molar ratio of 10 to 15:1, and the copper salt is selected from one or any combination of copper acetate, copper carbonate, copper nitrate, and copper chloride.

[0017] Furthermore, the temperature of the reactor in S3 is 80-100° C., the temperature of the distillation column is 60-95° C., and the two solutions are added in parallel for a reaction time of 4-12 hours.

[0018] Furthermore, in S4, the pH of the slurry is controlled at 8-9.

[0019] Furthermore, the precipitant in S5 is selected from one or any combination of sodium carbonate, ammonia water, sodium hydroxide, and urea, and the dispersant is selected from one or any combination of PVP, PEG, and dopamine.

[0020] Furthermore, the pressing conditions in S6 are: pressing pressure 10-30 MPa, pressing time 600-1800 seconds, drying temperature 105°C, drying time 4 hours, roasting temperature 350-800°C, time 3-6 hours.

[0021] An application of an oxalate hydrogenation catalyst for catalyzing the hydrogenation of oxalate to produce ethanol, wherein the application method comprises: loading the catalyst into a fixed bed reactor, controlling the reaction pressure to 1.5-3.0 MPa, the reaction temperature to 200-280°C, the hydrogen-ester ratio to 60-120, and the liquid phase space velocity to 0.2-0.8 h -1 , use a plunger pump and a mass flow meter to control the reaction materials and hydrogen to enter the device for mixing and reaction.

[0022] By means of the above scheme, the present invention has at least the following advantages:

[0023] The present invention prepares the carrier by a reactive distillation method, retains the activity of the existing carrier, reduces the carrier preparation process, and reduces the influence of impurity introduction on the catalyst. The copper nitrate solution and the other two carrier components are added to the reaction at a controlled rate in parallel flow, and the copper element reacts to generate copper phyllosilicate and copper oxide, which significantly improves its binding effect with SiO2 and TiO2, so that it can be used as both a carrier and an active site, and also greatly improves the possibility and strength performance of the later catalyst extrusion molding, avoids the high-cost and complex molding process that requires crushing and tableting, and reduces the loss of catalyst in tableting production. The carrier modification is very good at adjusting the acidity and alkalinity of the catalyst after activation, which is conducive to promoting the loading effect of the active component and adjusting the adsorption-reaction-diffusion-coupling effect between the material and the catalyst, and improving the selectivity of the catalyst. The selection of ⅧB or / and IB group active components and the application of the parallel flow coprecipitation method are applied, and the desired extruded catalyst with easy molding and high strength is finally obtained after being calcined at a suitable calcination temperature. The dispersibility of the active component is greatly improved, and it is used for oxalate hydrogenation to synthesize ethanol to achieve good results. The catalyst is used to hydrogenate oxalate to prepare ethanol, which has the advantages of high catalytic activity, high selectivity and good stability. The oxalate conversion rate is 100%, and the ethanol selectivity is over 93%, which has broad application prospects.

[0024] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the preferred embodiments of the present invention are described in detail as follows. DETAILED DESCRIPTION

[0025] The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0026] A catalyst for oxalate hydrogenation comprises the following steps: preparing a carrier by reactive distillation, modifying the carrier with magnesium salt, and finally adopting a parallel flow method to obtain a catalyst comprising 25-60wt% silicon oxide, 20-40wt% copper oxide, 10-60wt% titanium oxide, 0.5-2wt% magnesium oxide, and the remainder being catalyst active components.

[0027] The carrier is made of silicon oxide, copper oxide and titanium oxide in a certain proportion. The carrier modification component is a soluble magnesium salt, specifically one or a combination of magnesium sulfate, magnesium nitrate, magnesium chloride, magnesium acetate and magnesium carbonate, and the active component is selected from one or any several soluble metal salts in group VIII B or / and IB, preferably nickel salt or / and palladium salt.

[0028] A catalyst for oxalate hydrogenation and a preparation method thereof, comprising the following preparation steps:

[0029] S1. Load a certain amount of activated acidic sulfonic acid resin into a jacketed thermostatic distillation column, and add a certain amount of deionized water and urea to the bottom of the reactor;

[0030] S2. Tetrabutyl titanate, tetraethyl silicate and water are mixed in proportion for later use, and a copper salt solution and a magnesium salt solution of a certain concentration are prepared for later use; the mixing in proportion has a water-ester molar ratio of 10 to 15:1, and the copper salt is selected from one or any combination of copper acetate, copper carbonate, copper nitrate and copper chloride.

[0031] S3, start stirring and heat the reactor to the specified temperature, and at the same time increase the temperature of the distillation column. After the reaction conditions meet the reaction requirements, according to the material ratio and reaction time, add the two solutions of S2 to the reactor at a controlled rate. After the addition is complete, keep the temperature and continue the reaction for a period of time to obtain the carrier L; the temperature of the reactor is 80-100°C, the temperature of the distillation column is 60-95°C, and the two solutions are added in parallel for 4-12 hours.

[0032] S4, control the pH of L slurry to 8-9, add the magnesium salt solution prepared in S2 dropwise, and stir for 0.5-2h after the addition is completed to obtain modified carrier B;

[0033] S5. A precipitant and a mixed salt solution containing a certain proportion of a dispersant are simultaneously added dropwise to the B slurry to carry out an active component loading reaction. After the reaction is completed, the catalyst slurry J is obtained by aging; the precipitant is selected from one or any combination of sodium carbonate, ammonia water, sodium hydroxide, and urea, and the dispersant is selected from one or any combination of PVP, PEG, and dopamine.

[0034] S6. Filter, wash, press, extrude, dry and calcine the J slurry to obtain the finished catalyst product LBJ; the pressing conditions are: pressing pressure 10-30 MPa, pressing time 600-1800 s, drying temperature 105°C, drying time 4 h, calcination temperature 350-800°C, time 3-6 h.

[0035] The catalyst is used to catalyze the hydrogenation of oxalate to produce ethanol. The specific application method is:

[0036] The catalyst is loaded into a fixed bed reactor, and the reaction pressure is controlled at 1.5-3.0 MPa, the reaction temperature is 200-280°C, the hydrogen-ester ratio is 60-120, and the liquid phase space velocity is 0.2-0.8 h -1 , use a plunger pump and a mass flow meter to control the reaction materials and hydrogen entering the device for mixed reaction.

[0037] Example 1

[0038] Weigh 159.3g of tetrabutyl titanate and 176.02g of tetraethyl silicate into a beaker, add 270mL of deionized water and mix, prepare solution I, take 15.2g of copper nitrate trihydrate and 5.32g of magnesium acetate tetrahydrate and dissolve them in deionized water, prepare solutions II and III, take 0.33g of palladium chloride, 24.8g of nickel nitrate hexahydrate and 1.0g of PVP and dissolve them in deionized water, prepare mixed solution IV, add 2.5L of deionized water and 7.55g of urea to the reactor, stir and dissolve, heat to 90°C, and heat the distillation column to 75°C. Add solution I and solution II to the reactor for 8h in parallel with a peristaltic pump for reaction, and age for a period of time after the addition to obtain slurry L. When the pH of the reaction solution is 8.5-9.0 after aging, add solution III dropwise, and the addition time is controlled within 1h to obtain modified carrier slurry B. 5% ammonia water and mixed solution IV were added to the B slurry at the same time to load the active components. The addition time was 3 hours. When the endpoint pH reached neutrality, the catalyst slurry J was aged. The J slurry was cooled and filtered, washed with deionized water until the conductivity was less than 1000us / cm, the filter cake was pressed at a pressure of 25Mpa for 900s, formed into strips, dried at 120°C in a drying oven for 3 hours, and calcined at 500°C in a muffle furnace for 4 hours to obtain the finished catalyst LBJ-1.

[0039] Example 2

[0040] Weigh 137.9g ​​of tetrabutyl titanate and 176.02g of tetraethyl silicate into a beaker, add 270mL of deionized water and mix, prepare solution I, take 30.4g of copper nitrate trihydrate and 5.32g of magnesium acetate tetrahydrate and dissolve them in deionized water, prepare solutions II and III, take 0.33g of palladium chloride, 24.8g of nickel nitrate hexahydrate and 1.0g of PVP and dissolve them in deionized water, prepare mixed solution IV, add 2.5L of deionized water and 7.55g of urea to the reactor, stir and dissolve, heat to 90°C, and heat the distillation column to 75°C. Add solution I and solution II to the reactor for 8h in parallel with a peristaltic pump for reaction, and age for a period of time after the addition to obtain slurry L. When the pH of the reaction solution is 8.5-9.0 after aging, add solution III dropwise, and the addition time is controlled within 1h to obtain modified carrier slurry B. 5% ammonia water and mixed solution IV were added to the B slurry at the same time to load the active components. The addition time was 3 hours. When the endpoint pH reached neutrality, the catalyst slurry J was aged. The J slurry was cooled and filtered, washed with deionized water until the conductivity was less than 1000us / cm, the filter cake was pressed at a pressure of 25Mpa for 900s, formed into strips, dried at 120°C in a drying oven for 3 hours, and calcined at 500°C in a muffle furnace for 4 hours to obtain the finished catalyst LBJ-2.

[0041] Example 3

[0042] Weigh 95.3g of tetrabutyl titanate and 176.02g of tetraethyl silicate into a beaker, add 270mL of deionized water and mix, prepare solution I, take 91.2g of copper nitrate trihydrate and 5.32g of magnesium acetate tetrahydrate and dissolve them in deionized water, prepare solutions II and III, take 0.33g of palladium chloride, 24.8g of nickel nitrate hexahydrate and 1.0g of PVP and dissolve them in deionized water, prepare mixed solution IV, add 2.5L of deionized water and 7.55g of urea to the reactor, stir and dissolve, heat to 90°C, and heat the distillation column to 75°C. Add solution I and solution II to the reactor for 8h in parallel with a peristaltic pump for reaction, and age for a period of time after the addition to obtain slurry L. After aging, when the pH of the reaction solution is between 8.5 and 9.0, add solution III dropwise, and the addition time is controlled within 1h to obtain modified carrier slurry B. 5% ammonia water and mixed solution IV were added dropwise to slurry B to load the active components for 3 hours. When the endpoint pH reached neutrality, the slurry was aged to obtain catalyst slurry J. The slurry J was cooled and filtered, washed with deionized water until the conductivity was less than 1000us / cm, the filter cake was pressed at a pressure of 25Mpa for 900s, formed into strips, dried at 120°C in a drying oven for 3 hours, and calcined at 500°C in a muffle furnace for 4 hours to obtain the finished catalyst LBJ-3.

[0043] Example 4

[0044] Weigh 52.8g of tetrabutyl titanate and 176.02g of tetraethyl silicate into a beaker, add 270mL of deionized water and mix, prepare solution I, take 60.4g of copper nitrate trihydrate and 5.32g of magnesium acetate tetrahydrate and add deionized water to dissolve, prepare solutions II and III, take 0.33g of palladium chloride, 24.8g of nickel nitrate hexahydrate and 1.0g of PVP and add deionized water to dissolve, prepare mixed solution IV, add 2.5L of deionized water and 7.55g of urea to the reactor, stir and dissolve, heat to 90°C, and heat the distillation column to 75°C. Add solution I and solution II to the reactor for 8h in parallel with a peristaltic pump for reaction, and age for a period of time after the addition to obtain slurry L. When the pH of the reaction solution is 8.5-9.0 after aging, add solution III dropwise, and the addition time is controlled within 1h to obtain modified carrier slurry B. 5% ammonia water and mixed solution IV were added to the B slurry at the same time to load the active components. The addition time was 3 hours. When the endpoint pH reached neutrality, the slurry was aged to obtain the catalyst slurry J. The J slurry was cooled and filtered, washed with deionized water until the conductivity was less than 1000us / cm, the filter cake was pressed at a pressure of 25Mpa for 900s, formed into strips, dried at 120°C in a drying oven for 3 hours, and calcined at 500°C in a muffle furnace for 4 hours to obtain the finished catalyst LBJ-4.

[0045] Example 5

[0046] Weigh 10.56g of tetrabutyl titanate and 176.02g of tetraethyl silicate into a beaker, add 270mL of deionized water and mix, prepare solution I, take 121.48g of copper nitrate trihydrate and 5.32g of magnesium acetate tetrahydrate and add deionized water to dissolve, prepare solutions II and III, take 0.33g of palladium chloride, 24.8g of nickel nitrate hexahydrate and 1.0g of PVP and add deionized water to dissolve, prepare mixed solution IV, add 2.5L of deionized water and 7.55g of urea to the reactor, stir and dissolve, heat to 90°C, and heat the distillation column to 75°C. Solution I and solution II are added to the reactor in parallel for 8h using a peristaltic pump for reaction, and the solution is aged for a period of time after the addition is completed to obtain slurry L. When the pH of the reaction solution is 8.5-9.0 after aging, solution III is added dropwise, and the addition time is controlled within 1h to obtain modified carrier slurry B. 5% ammonia water and mixed solution IV were added to the B slurry at the same time to load the active components. The addition time was 3 hours. When the endpoint pH reached neutrality, the catalyst slurry J was aged. The J slurry was cooled and filtered, washed with deionized water until the conductivity was less than 1000us / cm, the filter cake was pressed at a pressure of 25Mpa for 900s, formed into strips, dried at 120°C in a drying oven for 3 hours, and calcined at 500°C in a muffle furnace for 4 hours to obtain the finished catalyst LBJ-5.

[0047] Example 6

[0048] Weigh 52.8g of tetrabutyl titanate and 176.02g of tetraethyl silicate into a beaker, add 270mL of deionized water and mix, prepare solution I, take 60.4g of copper nitrate trihydrate and 5.32g of magnesium acetate tetrahydrate and add deionized water to dissolve, prepare solutions II and III, take 24.8g of nickel nitrate hexahydrate and 1.0g of PVP and add deionized water to dissolve, prepare mixed solution IV, add 2.5L of deionized water and 7.55g of urea to the reactor, stir and dissolve, heat to 90°C, and heat the distillation column to 75°C. Solution I and solution II are added to the reactor in parallel with a peristaltic pump for 8h for reaction, and the solution is aged for a period of time after the addition is completed to obtain slurry L. When the pH of the reaction solution is 8.5-9.0 after aging, solution III is added dropwise, and the addition time is controlled within 1h to obtain modified carrier slurry B. 5% ammonia water and mixed solution IV were added to the B slurry at the same time to load the active components. The addition time was 3 hours. When the endpoint pH reached neutrality, the catalyst slurry J was aged. The J slurry was cooled and filtered, washed with deionized water until the conductivity was less than 1000us / cm, the filter cake was pressed at a pressure of 25Mpa for 900s, formed into strips, dried at 120°C in a drying oven for 3 hours, and calcined at 500°C in a muffle furnace for 4 hours to obtain the finished catalyst LBJ-6.

[0049] Example 7

[0050] Weigh 52.8g of tetrabutyl titanate and 176.02g of tetraethyl silicate into a beaker, add 270mL of deionized water and mix, prepare solution I, take 60.4g of copper nitrate trihydrate and 5.32g of magnesium acetate tetrahydrate and dissolve them in deionized water, prepare solutions II and III, take 0.33g of palladium chloride and 1.0g of PVP and dissolve them in deionized water, prepare mixed solution IV, add 2.5L of deionized water and 7.55g of urea to the reactor, stir and dissolve, heat to 90°C, and heat the distillation column to 75°C. Use a peristaltic pump to add solution I and solution II to the reactor for 8h in parallel for reaction, and age for a period of time after the addition to obtain slurry L. When the pH of the reaction solution is 8.5-9.0 after aging, add solution III dropwise, and the addition time is controlled within 1h to obtain modified carrier slurry B. 5% ammonia water and mixed solution IV were added to the B slurry at the same time to load the active components. The addition time was 3 hours. When the endpoint pH reached neutrality, the catalyst slurry J was aged. The J slurry was cooled and filtered, washed with deionized water until the conductivity was less than 1000us / cm, the filter cake was pressed at a pressure of 25Mpa for 900s, formed into strips, dried at 120°C in a drying oven for 3 hours, and calcined at 500°C in a muffle furnace for 4 hours to obtain the finished catalyst LBJ-7.

[0051] Example 8

[0052] Weigh 52.8g of tetrabutyl titanate and 176.02g of tetraethyl silicate into a beaker, add 270mL of deionized water and mix, prepare solution I, take 60.4g of copper nitrate trihydrate and 5.32g of magnesium acetate tetrahydrate and add deionized water to dissolve, prepare solutions II and III, take 0.33g of palladium chloride, 24.8g of nickel nitrate hexahydrate and 1.0g of PVP and add deionized water to dissolve, prepare mixed solution IV, add 2.5L of deionized water and 7.55g of urea to the reactor, stir and dissolve, heat to 90°C, and heat the distillation column to 75°C. Add solution I and solution II to the reactor for 8h in parallel with a peristaltic pump for reaction, and age for a period of time after the addition to obtain slurry L. When the pH of the reaction solution is 8.5-9.0 after aging, add solution III dropwise, and the addition time is controlled within 1h to obtain modified carrier slurry B. 5% ammonia water and mixed solution IV were added dropwise to slurry B to load the active components for 3 hours. When the endpoint pH reached neutrality, the slurry was aged to obtain catalyst slurry J. The slurry J was cooled and filtered, washed with deionized water until the conductivity was less than 1000us / cm, the filter cake was pressed at a pressure of 25Mpa for 900s, formed into strips, dried at 120°C in a drying oven for 3 hours, and calcined at 400°C in a muffle furnace for 4 hours to obtain the finished catalyst LBJ-8.

[0053] Example 9

[0054] Weigh 52.8g of tetrabutyl titanate and 176.02g of tetraethyl silicate into a beaker, add 270mL of deionized water and mix, prepare solution I, take 60.4g of copper nitrate trihydrate and 5.32g of magnesium acetate tetrahydrate and add deionized water to dissolve, prepare solutions II and III, take 0.33g of palladium chloride, 24.8g of nickel nitrate hexahydrate and 1.0g of PVP and add deionized water to dissolve, prepare mixed solution IV, add 2.5L of deionized water and 7.55g of urea to the reactor, stir and dissolve, heat to 90°C, and heat the distillation column to 75°C. Add solution I and solution II to the reactor for 8h in parallel with a peristaltic pump for reaction, and age for a period of time after the addition to obtain slurry L. When the pH of the reaction solution is 8.5-9.0 after aging, add solution III dropwise, and the addition time is controlled within 1h to obtain modified carrier slurry B. 5% ammonia water and mixed solution IV were added dropwise to slurry B to load the active components. The addition time was 3 hours. When the endpoint pH reached neutrality, the slurry was aged to obtain catalyst slurry J. The slurry J was cooled and filtered, washed with deionized water until the conductivity was less than 1000us / cm, the filter cake was pressed at a pressure of 25Mpa for 900s, formed into strips, dried in a drying oven at 120°C for 3 hours, and calcined in a muffle furnace at 600°C for 4 hours to obtain the finished catalyst LBJ-9.

[0055] Comparative Example 1

[0056] According to the formula of Example 4, solution I and copper nitrate solution were directly added into the reaction kettle to prepare L, and the subsequent preparation steps were the same to obtain catalyst LBJ-10.

[0057] Comparative Example 2

[0058] According to the formulation of Example 4, tetrabutyl titanate and tetraethyl silicate were replaced with silica sol and titanium dioxide powder, and the subsequent preparation steps were the same to obtain catalyst LBJ-11.

[0059] Comparative Example 3

[0060] Catalyst LBJ-12 was prepared according to the formulation of Example 4 without adding the carrier modification auxiliary agent magnesium acetate tetrahydrate.

[0061] Comparative Example 4

[0062] During the preparation process, solution II was not added, and the rest of the ingredients were prepared according to the formula of Example 4 to obtain catalyst LBJ-13.

[0063] Catalyst evaluation: Catalysts LBJ-10 to LBJ-13 prepared in Examples 1-9 and Comparative Examples 1-4 were used in the hydrogenation of dimethyl oxalate to ethanol.

[0064] The application conditions are as follows:

[0065] The catalyst was loaded into a fixed bed reactor, and the reaction pressure was controlled at 2.2 MPa, the reaction temperature at 493 K, the hydrogen / ester molar ratio at 90:1, and the liquid hourly space velocity at 0.5 h -1 , a plunger pump and a mass flow meter were used to control the reaction materials and hydrogen to enter the device. Under this condition, dimethyl oxalate was hydrogenated to obtain a crude ethanol reaction liquid. The reaction liquid sample was quantitatively analyzed by a calibrated gas chromatograph, and the results are shown in Table 1.

[0066] Table 1 Catalyst evaluation results and performance test data

[0067]

[0068]

[0069] From the test data and in the above table, it can be seen that the carrier preparation of Comparative Example 1 does not adopt the reactive distillation method, and the final catalyst product strength, dimethyl oxalate conversion rate and ethanol selectivity are significantly reduced; Comparative Example 2 uses silica sol and titanium dioxide powder to replace the raw material preparation carrier of the present invention, and the final dimethyl oxalate conversion rate and ethanol selectivity are also significantly reduced; Comparative Example 3 does not add a carrier modification auxiliary agent, and the dimethyl oxalate conversion rate and ethanol selectivity are reduced to a certain extent; Comparative Example 4 does not add copper nitrate in the carrier preparation, the catalyst cannot be extruded, and the dimethyl oxalate conversion rate and ethanol selectivity are significantly reduced. It can be confirmed that the present invention uses a reactive distillation method to prepare the carrier, retains the activity of the existing carrier, and reduces the carrier preparation process, reducing the impact of impurity introduction on the catalyst. The copper nitrate solution and the other two carrier components are added to the reaction at a controlled rate in parallel flow. After the copper element reacts, copper phyllosilicate and copper oxide are generated, which significantly improves its binding effect with SiO2 and TiO2, making it both a carrier and an active site. It also greatly improves the possibility and strength performance of the catalyst extrusion molding in the later stage, avoiding the high-cost and complex molding process that requires crushing and tableting, and reducing the loss of catalyst in tableting production. The carrier modification can well adjust the acidity and alkalinity of the catalyst after activation, which is beneficial to promote the loading effect of the active components and adjust the adsorption-reaction-diffusion-coupling effect between the material and the catalyst, thereby improving the selectivity of the catalyst. The selection of ⅧB or / and IB group active components and the application of the parallel flow coprecipitation method, after calcination at a suitable calcination temperature, finally obtain the desired easy-to-form and high-strength extruded catalyst. The dispersibility of the active components is greatly improved, and good results are achieved in the hydrogenation of oxalate to synthesize ethanol. The catalyst is used to hydrogenate oxalate to prepare ethanol, which has the advantages of high catalytic activity, high selectivity and good stability. The oxalate conversion rate is 100%, and the ethanol selectivity is more than 93%, which has broad application prospects.

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the technical principles of the present invention, and these improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing a catalyst for hydrogenation of oxalate, characterized in that: The carrier is prepared by reactive distillation and modified with magnesium salt to obtain a catalyst comprising 25-60 wt % silicon oxide, 20-40 wt % copper oxide, 10-60 wt % titanium oxide, 0.5-2 wt % magnesium oxide, and the remainder being catalyst active components; The specific preparation steps are: S1. Load a certain amount of activated acidic sulfonic acid resin into a jacketed thermostatic distillation column, and add a certain amount of deionized water and urea to the bottom of the reactor; S2, tetrabutyl titanate, tetraethyl silicate and water are mixed in proportion to prepare solution I, and a certain concentration of copper salt solution II and magnesium salt solution III are prepared for standby use; S3, start stirring to heat the reactor to a specified temperature, and at the same time raise the temperature of the distillation column. After the reaction conditions meet the reaction requirements, according to the material ratio and reaction time, add solution I and solution II in S2 to the reactor at a controlled rate. After the addition is complete, keep the temperature and continue the reaction for a period of time to obtain carrier L; S4, control the pH of slurry L, add the magnesium salt solution prepared in S2 dropwise, and stir for 0.5-2h after the addition is completed to obtain modified carrier B; S5, adding a precipitant and a mixed salt solution containing a certain proportion of a dispersant to the modified carrier B slurry at the same time to carry out an active component loading reaction, and after the reaction is completed, aging to obtain a catalyst slurry J; S6. Filter, wash, squeeze, extrude, dry and calcine the catalyst slurry J to obtain the finished catalyst product LBJ.

2. A method for preparing a catalyst for oxalate hydrogenation according to claim 1, characterized in that: The carrier is made of silicon oxide, copper oxide and titanium oxide in a certain proportion.

3. The method for preparing a catalyst for oxalate hydrogenation according to claim 1, characterized in that: The magnesium salt is one or a combination of magnesium sulfate, magnesium nitrate, magnesium chloride, magnesium acetate and magnesium carbonate, and the active component is selected from one or any several soluble metal salts of group VIB or IB.

4. The method for preparing a catalyst for oxalate hydrogenation according to claim 1, characterized in that: The mixing in proportion described in S2 means that the molar ratio of water to ester is 10-15:1, and the copper salt is selected from one or any combination of copper acetate, copper carbonate, copper nitrate and copper chloride.

5. The method for preparing a catalyst for oxalate hydrogenation according to claim 1, characterized in that: The temperature of the reactor in S3 is 80-100°C, the temperature of the distillation column is 60-95°C, and the solution I and solution II are added in parallel for a reaction time of 4-12 hours.

6. The method for preparing a catalyst for oxalate hydrogenation according to claim 1, characterized in that: S4: The pH of the slurry is controlled at 8-9.

7. The method for preparing a catalyst for oxalate hydrogenation according to claim 1, characterized in that: S5 The precipitant is selected from one or any combination of sodium carbonate, ammonia, sodium hydroxide and urea, and the dispersant is selected from one or any combination of PVP, PEG and dopamine.

8. The method for preparing a catalyst for oxalate hydrogenation according to claim 1, characterized in that: The pressing conditions described in S6 are: pressing pressure 10~30Mpa, pressing time 600~1800 S, drying temperature 105℃, drying time 4h, roasting temperature 350~800℃, time 3~6h.

9. Use of the catalyst for hydrogenation of oxalate obtained by the preparation method according to any one of claims 1 to 8, characterized in that: It is used for catalytic oxalate hydrogenation synthesis to produce ethanol. The application method is: the catalyst is loaded into a fixed bed reactor, the reaction pressure is controlled to be 1.5~3.0Mpa, the reaction temperature is 200~280℃, the hydrogen-ester ratio is 60~120, and the liquid phase space velocity is 0.2~0.8 h -1 , use a plunger pump and a mass flow meter to control the reaction materials and hydrogen to enter the device for mixing and reaction.

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