A hydrogenolysis catalyst, its preparation and use

Abstract

The application provides a hydrogenolysis catalyst and a preparation method and application thereof, and belongs to the technical field of catalysts. The preparation method provided by the application comprises the following steps: providing a composite metal compound containing copper, zinc and aluminum; mixing and treating the composite metal compound with lithium carboxymethyl cellulose and a forming aid to obtain a mixed powder; mixing and treating the mixed powder with an acidic aluminum sol, and then performing extrusion molding, drying and calcination to obtain the hydrogenolysis catalyst. The hydrogenolysis catalyst provided by the application has the advantages of high dispersion degree of active components, smooth catalyst pore channel, stable structure and good strength. When the hydrogenolysis catalyst is used for catalyzing dimethyl benzyl alcohol hydrogenolysis to prepare cumene, the conversion rate of dimethyl benzyl alcohol is greater than 99.9%, the selectivity of cumene is greater than 99%, and the hydrogenolysis catalyst has a good application prospect.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of catalysis technology, and particularly relates to a hydrogenolysis catalyst and a preparation method and application thereof. BACKGROUND

[0002] The main industrial production methods of propylene oxide (PO) include chlorohydrination, direct oxidation with hydrogen peroxide and co-oxidation (Halcon method). The chlorohydrination method is the main route for producing PO at present, and this process has serious problems such as equipment corrosion and environmental pollution. The direct oxidation with hydrogen peroxide route is affected in economy due to high raw material cost.

[0003] The co-oxidation method is to generate propylene oxide by reacting organic peroxide and propylene. The traditional isobutane co-oxidation method and ethylbenzene co-oxidation method avoid the serious environmental pollution of the chlorohydrination method with high investment and long process, but a large amount of by-products are co-produced in the production of PO, and the production cost of PO is greatly affected by the price fluctuation of the co-products.

[0004] The cumene co-oxidation method (PO-CHP process) includes three core reactions of cumene peroxidation, propylene epoxidation and dimethylbenzyl alcohol hydrogenolysis and related separation processes, and hydrogen peroxide cumene is used as the oxygen source. The co-produced dimethylbenzyl alcohol is converted into cumene by hydrogenolysis, and the cumene returns to the peroxidation unit to obtain hydrogen peroxide cumene, so that the cumene is recycled. Compared with other processes, the cumene co-oxidation method has the advantages of very high conversion rate and selectivity, short process route, less equipment investment, no co-products and more stable economic benefits.

[0005] The dimethylbenzyl alcohol hydrogenolysis reaction is one of the core reactions of the PO-CHP process. The dimethylbenzyl alcohol hydrogenolysis catalyst mainly includes platinum-palladium noble metal catalyst, nickel-based catalyst and copper-based catalyst, which are reported in many patents.

[0006] US3337646 proposes a method for preparing cumene by gas phase hydrogenolysis of α,α-dimethylbenzyl alcohol, which uses a Ni-Cr-Al2O3 catalyst. The catalyst contains Cr, and there are serious environmental pollution problems in the preparation, use and recovery treatment of the catalyst.

[0007] CN1308273C discloses a method for preparing cumene by catalytic hydrogenolysis of α,α-dimethylbenzyl alcohol. The patent uses a 2wt% Pd-C catalyst, and the catalyst has high cost. In addition, halogenated aromatic hydrocarbons, sodium formate, formic acid and indole and other substances need to be introduced during the reaction, which increases the difficulty and cost of separation.

[0008] At present, the catalyst prepared by the existing technology has low activity and poor selectivity when used for preparing cumene by catalytic hydrogenolysis of dimethylbenzyl alcohol. Therefore, it is of great significance to develop a hydrogenolysis catalyst with excellent hydrogenolysis performance. SUMMARY

[0009] To solve the problems of low activity and poor selectivity in the existing hydrogenolysis catalyst, the present application provides a hydrogenolysis catalyst, a preparation method and application thereof. The hydrogenolysis catalyst prepared by the preparation method has excellent activity and selectivity.

[0010] In the first aspect, the present application provides a preparation method of a hydrogenolysis catalyst, comprising:

[0011] providing a composite metal compound containing copper, zinc and aluminum;

[0012] mixing and treating the composite metal compound with lithium carboxymethyl cellulose and a forming aid to obtain a mixed powder;

[0013] mixing and treating the mixed powder with an acidic aluminum sol, and then extruding, drying and calcining to obtain the hydrogenolysis catalyst.

[0014] In the preparation method, the addition of the acidic aluminum sol makes the free H + The copper, zinc and aluminum in the composite metal compound react with the free H in the acidic aluminum sol to improve the adhesion, thereby improving the strength of the hydrogenolysis catalyst. Meanwhile, the lithium carboxymethyl cellulose has good adhesion performance and can form aluminum lithium spinel after high-temperature calcination, which can effectively improve the structural stability of the hydrogenolysis catalyst. Moreover, the Li in the lithium carboxymethyl cellulose is an auxiliary element, which can reduce the acidity of the hydrogenolysis catalyst, thereby inhibiting the dehydration and polymerization reactions of α,α-dimethylbenzyl alcohol, and is conducive to improving the selectivity and stability of the hydrogenolysis catalyst. In addition, the lithium carboxymethyl cellulose is also conducive to improving the strength of the hydrogenolysis catalyst, increasing the number of pores in the hydrogenolysis catalyst, and improving the mass transfer performance of the hydrogenolysis catalyst, thereby obtaining a hydrogenolysis catalyst with high reaction activity.

[0015] In some embodiments, the particle size of the lithium carboxymethyl cellulose is greater than 200 mesh.

[0016] In the preparation method, if the particle size of the lithium carboxymethyl cellulose is too large, it is difficult to achieve high dispersion, and if the particle size of the lithium carboxymethyl cellulose is too small (particle size greater than 200 mesh), better dispersion can be achieved, which is conducive to reducing the acidity of the hydrogenolysis catalyst and improving the structural stability of the hydrogenolysis catalyst.

[0017] In some embodiments, the concentration of the acidic aluminum sol is 20-40wt%, for example, it can be 20wt%, 22wt%, 24wt%, 26wt%, 28wt%, 30wt%, 32wt%, 34wt%, 36wt%, 38wt%, 40wt% or other values within the range.

[0018] The preparation method provided by the present application has the following problems: if the concentration of the acidic aluminum sol is too high, the stability of the prepared hydrogenolysis catalyst is poor and the hydrogenolysis catalyst is easy to deteriorate; if the concentration of the acidic aluminum sol is too low, the adhesion is poor, which leads to the decrease of the strength of the hydrogenolysis catalyst.

[0019] In some embodiments, the pH value of the acidic aluminum sol is 1-3, for example, 1, 1.2, 1.4, 1.6, 1.8, 2, 3 or other values in the range; wherein the particle size of the aluminum sol is 1-10 nm, for example, 1-5 nm, 5-10 nm or other ranges in the range.

[0020] In the preparation method provided by the present application, if the pH value of the acidic aluminum sol is too low, the active component is damaged due to the strong acidity, which leads to the decrease of the activity of the prepared hydrogenolysis catalyst; if the pH value of the acidic aluminum sol is too high, the adhesion is poor, which leads to the decrease of the strength of the hydrogenolysis catalyst.

[0021] In some preferred embodiments, the acidic aluminum sol is prepared by the nitric acid method.

[0022] In some more preferred embodiments, the content of chlorine in the acidic aluminum sol is less than 50 ppm.

[0023] In the preparation method provided by the present application, by further using the acidic aluminum sol prepared by the nitric acid method and controlling the content of chlorine to be less than 50 ppm, the selectivity of the hydrogenolysis catalyst can be improved.

[0024] In some preferred embodiments, the diameter of the hydrogenolysis catalyst is 1.5-3 mm, for example, 1.5 mm, 1.8 mm, 2 mm, 2.1 mm, 2.4 mm, 2.7 mm, 3 mm or other values in the range; and the length is 1.5-4 mm, for example, 1.5 mm, 1.8 mm, 2 mm, 2.1 mm, 2.4 mm, 2.7 mm, 3 mm, 3.3 mm, 3.6 mm, 3.9 mm, 4 mm or other values in the range.

[0025] In the preparation method provided by the present application, by controlling the diameter and length of the hydrogenolysis catalyst within a suitable range, the reaction activity of the hydrogenolysis catalyst can be further improved.

[0026] In some embodiments, in the composite metal compound, the molar ratio of copper, zinc and aluminum is 1:0.1-0.5:0.5-1.5; preferably 1:0.08-0.4:0.6-1.4.

[0027] In some embodiments, the mass ratio of the composite metal compound to the lithium carboxymethyl cellulose is 2-10:1; preferably 3-7:1.

[0028] The hydrogenolysis catalyst prepared by the preparation method has the following advantages: Cu is an active element of the hydrogenolysis catalyst, and if the content of Cu is too low, the activity of the hydrogenolysis catalyst is reduced, and if the content of Cu is too high, the activity and stability of the hydrogenolysis catalyst are reduced due to poor dispersibility. ZnO and Al2O3 are carriers of the hydrogenolysis catalyst, and the composite carrier can make the active component highly dispersed, which is beneficial to obtain a high-efficiency hydrogenolysis catalyst with reliable strength and moderate acidity. If the content of ZnO and Al2O3 is too high, the activity of the hydrogenolysis catalyst is reduced, and if the content of ZnO and Al2O3 is too low, the dispersibility of the active component is poor, which further reduces the activity and stability of the hydrogenolysis catalyst. Li is an auxiliary element, which can reduce the acidity of the hydrogenolysis catalyst and improve the structural stability of the hydrogenolysis catalyst, and if the content of Li is too high, the activity of the hydrogenolysis catalyst is reduced, and if the content of Li is too low, the structural stability of the hydrogenolysis catalyst is reduced.

[0029] In some embodiments, the forming aid is present in an amount of 2-5% by weight of the mixed powder, for example 2%, 3%, 4%, 5% or another value within this range; preferably, the forming aid is amaranth powder.

[0030] In some embodiments, the mass ratio of the mixed powder to the acidic aluminum sol is 0.5-2.5:1; preferably 0.8-2:1.

[0031] In some embodiments, the method for preparing the composite metal compound comprises:

[0032] providing a mixed solution of a copper compound, a zinc compound and an aluminum compound, and a precipitant solution;

[0033] After the mixed solution and the precipitant solution are precipitated in parallel, drying (the temperature of drying is 100-120°C, for example 100°C, 105°C, 110°C, 120°C or another value within this range; the time is 4-12h, for example 4h, 6h, 8h, 10h, 12h or another value within this range), calcination (the temperature of calcination is 300-450°C, for example 300°C, 320°C, 340°C, 360°C, 380°C, 400°C, 420°C, 440°C, 450°C or another value within this range; the time is 2-8h, for example 2h, 4h, 6h, 8h or another value within this range) to obtain the composite metal compound.

[0034] In some embodiments, the copper compound is selected from one or more of copper nitrate, copper chloride and copper sulfate.

[0035] In some embodiments, the zinc compound is selected from one or more of zinc nitrate, zinc chloride and zinc sulfate.

[0036] In some embodiments, the aluminum compound is selected from one or more of aluminum nitrate, aluminum chloride and aluminum sulfate.

[0037] In some embodiments, the molar concentration of metal ions in the mixed solution is 1-2 mol / L, for example, can be 1 mol / L, 1.2 mol / L, 1.4 mol / L, 1.6 mol / L, 1.8 mol / L, 2 mol / L or other values within the range.

[0038] In some embodiments, the precipitant solution is a sodium carbonate solution; preferably, the mass concentration of the sodium carbonate solution is 10-30%.

[0039] In some embodiments, in the steps of extrusion molding, drying and calcination, the pressure of the extrusion molding is 100-200 N, for example, can be 100 N, 120 N, 140 N, 160 N, 180 N, 200 N or other values within the range; the screw rotation speed is 10-50 r / min, for example, can be 10 r / min, 20 r / min, 30 r / min, 40 r / min, 50 r / min or other values within the range.

[0040] In some embodiments, the temperature of the drying is 100-120℃, for example, can be 100℃, 105℃, 110℃, 120℃ or other values within the range; the time is 4-12 h, for example, can be 4 h, 6 h, 8 h, 10 h, 12 h or other values within the range.

[0041] In some embodiments, the temperature of the calcination is 600-800℃, for example, can be 600℃, 630℃, 660℃, 690℃, 720℃, 750℃, 780℃, 800℃ or other values within the range; the time is 2-8 h, for example, can be 2 h, 4 h, 6 h, 8 h or other values within the range.

[0042] In the present application, the extrusion molding material is cut into uniform catalyst particles by a pelletizer, compared with the catalyst obtained by conventional extrusion molding, drying and calcination (the length of the catalyst particles is usually 3-8 mm, for example, can be 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm or other values within the range), the length of the catalyst molding is significantly smaller, which is beneficial to improve the reaction activity.

[0043] In the second aspect, the present application provides a hydrogenolysis catalyst prepared by the preparation method of the hydrogenolysis catalyst provided by the present application.

[0044] In the third aspect, the present application provides the use of the hydrogenolysis catalyst in the preparation of cumene by catalyzing the hydrogenolysis of dimethylbenzyl alcohol.

[0045] In a fourth aspect, the present application provides a method for preparing cumene, comprising:

[0046] providing a hydrocarbon material containing α,α-dimethylbenzyl alcohol, hydrogen, and a hydrogenolysis catalyst, wherein the hydrogenolysis catalyst is prepared by the method for preparing a hydrogenolysis catalyst provided by the present application;

[0047] reducing the hydrogenolysis catalyst and contacting the hydrogenolysis catalyst with the hydrocarbon material containing α,α-dimethylbenzyl alcohol and the hydrogen to obtain cumene.

[0048] In some embodiments, the step of reducing the hydrogenolysis catalyst comprises reducing the hydrogenolysis catalyst in a mixed atmosphere of nitrogen and hydrogen.

[0049] Compared with the prior art, the present application has the following beneficial effects:

[0050] The present application has high dispersity of the active component of the dimethylbenzyl alcohol hydrogenolysis catalyst, unobstructed catalyst pore, stable structure, and good strength by adding lithium carboxymethyl cellulose and acidic aluminum sol to the composite metal compound. When the dimethylbenzyl alcohol hydrogenolysis catalyst is used to prepare cumene by hydrogenolysis of dimethylbenzyl alcohol, the conversion rate of dimethylbenzyl alcohol is greater than 99.9%, and the selectivity of cumene is greater than 99%. DETAILED DESCRIPTION

[0051] The technical solutions of the present application will be described clearly and completely in combination with specific examples. Obviously, the described examples are only some of the examples of the present application, but not all the examples. Based on the examples of the present application, all the other examples obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0052] The experimental methods not specified in the examples are usually carried out according to the conventional conditions and the conditions described in the manual, or according to the conditions suggested by the manufacturers. The general equipment, materials, reagents, etc. used are commercially available, unless otherwise specified.

[0053] In the present application, part of the raw materials are as follows:

[0054] Cumene is purchased from Shanghai Aldrin Biochemical Science and Technology Co., Ltd.

[0055] α,α-dimethylbenzyl alcohol is purchased from TCI Chemicals (Shanghai) Co., Ltd.

[0056] Acidic aluminum sol (pH 1-3, concentration 20-40 wt%, colloidal particle size 1-10 nm, prepared by nitric acid method, chlorine content <50 ppm) is purchased from Beijing Inokai Technology Co., Ltd.

[0057] Acidic aluminum sol (pH 3-4, concentration 25wt%, colloidal particle size 5-10 nm, prepared by hydrochloric acid method, chlorine content 9.1wt%) was purchased from Beijing InoKai Technology Co., Ltd.;

[0058] Basic aluminum sol (pH 8-10, concentration 25wt%, colloidal particle size 5-10 nm) was purchased from Beijing InoKai Technology Co., Ltd.;

[0059] Neutral aluminum sol (pH 6-8, concentration 25wt%, colloidal particle size 5-10 nm) was purchased from Beijing InoKai Technology Co., Ltd.;

[0060] Copper nitrate was purchased from Shanghai Aladdin Biochem Technology Co., Ltd.;

[0061] Zinc nitrate was purchased from Shanghai Aladdin Biochem Technology Co., Ltd.;

[0062] Aluminum nitrate was purchased from Shanghai Aladdin Biochem Technology Co., Ltd.;

[0063] Sodium carbonate was purchased from Shanghai Aladdin Biochem Technology Co., Ltd.;

[0064] Carboxymethyl cellulose lithium was purchased from Beijing InoKai Technology Co., Ltd.

[0065] The test method is as follows:

[0066] 1. Composition analysis of dimethylbenzyl alcohol hydrogenolysis catalyst, X-ray fluorescence spectrometer (XRF) was used;

[0067] 2. Dimethylbenzyl alcohol conversion rate = (1-moles of residual dimethylbenzyl alcohol in the reaction solution / moles of dimethylbenzyl alcohol contained in the raw material)*100%;

[0068] Cumene selectivity = moles of generated cumene / moles of converted dimethylbenzyl alcohol*100%;

[0069] Among them, the moles of dimethylbenzyl alcohol contained in the raw material, the moles of generated cumene and the moles of residual dimethylbenzyl alcohol in the reaction solution were calculated after Agilent 7820A gas chromatograph analysis, and the test conditions included: using DB-5 chromatographic column, FID detector, vaporizing chamber temperature was 260℃, detector temperature was 260℃, carrier gas was high-purity N2, and its flow rate was 30ml / min.

[0070] Example 1

[0071] A preparation method of a dimethylbenzyl alcohol hydrogenolysis catalyst, comprising the following steps:

[0072] (a) A mixed solution 1 was prepared by adding 2553 g of water, then adding 273.4 g of copper nitrate, 102.3 g of zinc nitrate and 92.2 g of aluminum nitrate into a reactor and stirring to dissolve; a solution 2 was prepared by dissolving 446.5 g of sodium carbonate in 1785.8 g of water; the mixed solution 1 and the solution 2 were precipitated in parallel flow, the precipitation reaction time was 1 h, the reaction temperature was 75°C, the aging time was 2 h, the aging temperature was 80°C, then after filtration and washing, drying at 110°C for 8 h and calcination at 300°C for 4 h to obtain a composite metal compound containing copper, zinc and aluminum;

[0073] (b) 155.6 g of the composite metal compound obtained in step (a) was mixed with 33.4 g of lithium carboxymethyl cellulose and 6 g of a molding aid, sesbania powder, to obtain a mixed powder;

[0074] (c) 169.6 g of an acidic aluminum sol (pH 2-3, concentration 25 wt%, colloidal particle size 5-10 nm, prepared by nitric acid method, chlorine content < 50 ppm) was added to the mixed powder obtained in step (b), mixed well and extruded, then pelletized, dried at 110°C for 4 h and calcined at 600°C for 4 h to obtain a hydrogenolysis catalyst A with a diameter of 2.0 mm and a length of 3.0 mm.

[0075] Example 2

[0076] A method for preparing a hydrogenolysis catalyst for dimethylbenzyl alcohol, comprising the following steps:

[0077] (a) A mixed solution 1 was prepared by adding 2512 g of water, then adding 303.7 g of copper nitrate, 81.9 g of zinc nitrate and 65.2 g of aluminum nitrate into a reactor and stirring to dissolve; a solution 2 was prepared by dissolving 439.4 g of sodium carbonate in 1757.5 g of water; the mixed solution 1 and the solution 2 were precipitated in parallel flow, the precipitation reaction time was 1.5 h, the reaction temperature was 80°C, the aging time was 2 h, the aging temperature was 85°C, then after filtration and washing, drying at 110°C for 6 h and calcination at 350°C for 4 h to obtain a composite metal compound containing copper, zinc and aluminum;

[0078] (b) 149.0 g of the composite metal compound obtained in step (a) was mixed with 26.7 g of lithium carboxymethyl cellulose and 6 g of a molding aid, sesbania powder, to obtain a mixed powder;

[0079] (c) 197.6 g of an acidic aluminum sol (pH 2-3, concentration 25 wt%, colloidal particle size 1-5 nm, prepared by nitric acid method, chlorine content < 50 ppm) was added to the mixed powder obtained in step (b), mixed well and extruded, then pelletized, dried at 110°C for 4 h and calcined at 650°C for 4 h to obtain a hydrogenolysis catalyst B with a diameter of 1.5 mm and a length of 2.5 mm.

[0080] Example 3

[0081] A preparation method of a dimethylbenzyl alcohol hydrogenolysis catalyst, comprising the following steps:

[0082] (a) first adding 2462 g of water into a reaction kettle, then adding 334.1 g of copper nitrate, 57.0 g of zinc nitrate and 70.6 g of aluminum nitrate, and fully stirring and dissolving to obtain a mixed solution 1; dissolving 430.6 g of sodium carbonate in 1722.3 g of water to obtain a solution 2; precipitating the mixed solution 1 and the solution 2 in parallel flow, with a precipitation reaction time of 2 h, a reaction temperature of 80 °C, an aging time of 1.5 h, and an aging temperature of 83 °C, and then filtering and washing, drying at 110 °C for 10 h, and calcining at 400 °C for 6 h to obtain a composite metal compound containing copper, zinc and aluminum;

[0083] (b) fully mixing 154.4 g of the composite metal compound obtained in step (a) with 40.0 g of lithium carboxymethyl cellulose and 6 g of a molding aid of sesbania powder to obtain a mixed powder;

[0084] (c) adding 123.4 g of an acidic aluminum sol (pH 2-3, concentration 35 wt%, colloidal particle size 1-5 nm, prepared by a nitric acid method, chlorine content < 50 ppm) into the mixed powder obtained in step (b), fully mixing and extruding into a shape, granulating, drying at 110 °C for 4 h, and calcining at 700 °C for 4 h to obtain a hydrogenolysis catalyst C with a diameter of 3.0 mm and a length of 3.0 mm.

[0085] Example 4

[0086] A preparation method of a dimethylbenzyl alcohol hydrogenolysis catalyst, comprising the following steps:

[0087] (a) first adding 2423 g of water into a reaction kettle, then adding 364.5 g of copper nitrate, 37.3 g of zinc nitrate and 66.7 g of aluminum nitrate, and fully stirring and dissolving to obtain a mixed solution 1; dissolving 423.8 g of sodium carbonate in 1695.1 g of water to obtain a solution 2; precipitating the mixed solution 1 and the solution 2 in parallel flow, with a precipitation reaction time of 2.5 h, a reaction temperature of 75 °C, an aging time of 3 h, and an aging temperature of 80 °C, and then filtering and washing, drying at 110 °C for 8 h, and calcining at 450 °C for 4 h to obtain a composite metal compound containing copper, zinc and aluminum;

[0088] (b) fully mixing 157.4 g of the composite metal compound obtained in step (a) with 30.0 g of lithium carboxymethyl cellulose and 6 g of a molding aid of sesbania powder to obtain a mixed powder;

[0089] (c) to the mixed powder obtained in step (b), 86.7 g of acid aluminum sol (pH 2-3, concentration 30 wt%, colloidal particle size 1-5 nm, prepared by nitric acid method, chlorine content < 50 ppm) was added, mixed thoroughly and extruded, granulated, dried at 110°C for 4 h, calcined at 720°C for 4 h to obtain hydrogenolysis catalyst E with a diameter of 2.0 mm and a length of 4.0 mm.

[0090] Example 5

[0091] A method for preparing a hydrogenolysis catalyst for dimethylbenzyl alcohol, comprising the following steps:

[0092] (a) in a reaction kettle, 2210 g of water was first added, then 394.8 g of copper nitrate, 62.1 g of zinc nitrate and 58.9 g of aluminum nitrate were added, and the mixture was stirred and dissolved to obtain a mixed solution 1; 386.4 g of sodium carbonate was dissolved in 1545.7 g of water to obtain a solution 2; the mixed solution 1 and the solution 2 were precipitated in parallel flow, the precipitation reaction time was 2 h, the reaction temperature was 85°C, the aging time was 3 h, the aging temperature was 88°C, and then after filtration and washing, it was dried at 110°C for 8 h and calcined at 450°C for 4 h to obtain a composite metal compound containing copper, zinc and aluminum;

[0093] (b) 171.0 g of the composite metal compound obtained in step (a) was mixed with 50.0 g of lithium carboxymethyl cellulose and 6 g of a molding aid, pearl millet powder, to obtain a mixed powder;

[0094] (c) to the mixed powder obtained in step (b), 86.7 g of acid aluminum sol (pH 2-3, concentration 30 wt%, colloidal particle size 1-5 nm, prepared by nitric acid method, chlorine content < 50 ppm) was added, mixed thoroughly and extruded, granulated, dried at 110°C for 4 h, calcined at 720°C for 4 h to obtain hydrogenolysis catalyst E with a diameter of 2.0 mm and a length of 4.0 mm.

[0095] Example 6

[0096] A method for preparing a hydrogenolysis catalyst for dimethylbenzyl alcohol, comprising the following steps:

[0097] (a) in a reaction kettle, 2330 g of water was first added, then 303.7 g of copper nitrate, 140.7 g of zinc nitrate and 66.2 g of aluminum nitrate were added, and the mixture was stirred and dissolved to obtain a mixed solution 1; 407.5 g of sodium carbonate was dissolved in 1630.2 g of water to obtain a solution 2; the mixed solution 1 and the solution 2 were precipitated in parallel flow, the precipitation reaction time was 1.5 h, the reaction temperature was 85°C, the aging time was 2 h, the aging temperature was 90°C, and then after filtration and washing, it was dried at 110°C for 8 h and calcined at 400°C for 4 h to obtain a composite metal compound containing copper, zinc and aluminum;

[0098] (b) The complex metal compound obtained in step (a) 165.5 g was mixed with 25.0 g of lithium carboxymethyl cellulose and 6 g of a molding aid, sesbania powder, to obtain a mixed powder;

[0099] (c) 94.3 g of an acidic aluminum sol (pH 2-3, concentration 35 wt%, colloidal particle size 1-5 nm, prepared by a nitric acid method, chlorine content < 50 ppm) was added to the mixed powder obtained in step (b), mixed well, and extrusion-molded, and then pelletized, dried at 110°C for 4 h, and calcined at 730°C for 4 h to obtain a hydrogenolysis catalyst F having a diameter of 2.5 mm and a length of 2.5 mm.

[0100] Comparative Example 1

[0101] A dimethylbenzyl alcohol hydrogenolysis catalyst was prepared according to the procedure of Example 1, except that lithium carboxymethyl cellulose was not used in step (c), and a catalyst G was obtained.

[0102] Comparative Example 2

[0103] A dimethylbenzyl alcohol hydrogenolysis catalyst was prepared according to the procedure of Example 1, except that all of the aluminum in the catalyst was derived from aluminum nitrate, and instead of extrusion-molding in step (c), a 3 mm * 3 mm cylindrical catalyst was obtained by compression molding, and the rest of the procedure was the same as in Example 1, and a catalyst H was obtained.

[0104] Comparative Example 3

[0105] A dimethylbenzyl alcohol hydrogenolysis catalyst was prepared according to the procedure of Example 1, except that the amount of lithium carboxymethyl cellulose added in step (b) was 10.0 g, and a catalyst I was obtained.

[0106] Comparative Example 4

[0107] A dimethylbenzyl alcohol hydrogenolysis catalyst was prepared according to the procedure of Example 1, except that the molded catalyst obtained in step (c) was not pelletized, and after calcination the catalyst was about 3-10 mm long, and a catalyst J was obtained.

[0108] Comparative Example 5

[0109] A dimethylbenzyl alcohol hydrogenolysis catalyst was prepared according to the procedure of Example 1, except that an alkaline aluminum sol (pH 8-10, concentration 25 wt%, colloidal particle size 5-10 nm) was used in step (c), and a catalyst K was obtained.

[0110] Comparative Example 6

[0111] A dimethylbenzyl alcohol hydrogenolysis catalyst was prepared according to the procedure of Example 1, except that a neutral aluminum sol (pH 6-8, concentration 25 wt%, colloidal particle size 5-10 nm) was used in step (c), and a catalyst L was obtained.

[0112] Comparative Example 7

[0113] The steps for preparing the dimethylbenzyl alcohol hydrogenolysis catalyst are the same as in Example 1, except that step (c) uses acidic aluminum sol (pH 3-4, concentration 25wt%, particle size 5-10nm, prepared by hydrochloric acid method, chlorine content 9.1wt%) to prepare catalyst L.

[0114] Catalyst performance testing

[0115] The catalysts prepared in Examples 1-6 and Comparative Examples 1-7 were respectively loaded into fixed-bed hydrogenation reactors, with a catalyst loading of 100 ml. Before use, the catalysts were reduced in a mixed atmosphere of nitrogen and hydrogen, maintaining a mixed gas hourly space velocity (VHSV) of 300 h⁻¹ during the reduction process. -1 First, the reactor temperature is raised to 160℃ and held at that temperature for 2 hours to remove the physical water adsorbed on the catalyst. Then, a mixture of hydrogen and nitrogen containing 5% H2 by volume is introduced for pre-reduction for 1 hour. After that, the proportion of hydrogen in the hydrogen and nitrogen mixture is gradually increased to 10%, 20%, 50%, and 100% by volume, while controlling the hot spot temperature of the catalyst bed to not exceed 250℃. Finally, the temperature is raised to 250℃ and reduced in a pure hydrogen atmosphere for 4 hours.

[0116] The reduced catalyst was added to a 25 wt% dimethylbenzyl alcohol solution in cumene, and the mixture was subjected to a reaction at a pressure of 2.0 MPa, a temperature of 140 °C, an H2 / alcohol molar ratio of 8:1, and a liquid hourly space velocity of 3 h⁻¹. -1 The reaction was carried out under the specified conditions. After the reaction was completed, the state of the catalyst was observed, the content was determined by gas chromatography, and the conversion rate of dimethylbenzyl alcohol and the selectivity of cumene were calculated. The results are shown in Table 1.

[0117] Catalyst strength testing method: The particle strength tester (DL3 type) was used for testing. Forty catalyst particles after the reaction were randomly selected for testing, and the average strength was calculated.

[0118] Table 1 Catalyst Evaluation Results

[0119]

[0120]

[0121] The results in the table show that the catalysts prepared in Examples 1-6 have good activity and selectivity, while the catalysts prepared in Comparative Examples 1-7 have low activity, and their selectivity and strength are significantly lower than those in the examples. The results indicate that the dimethylbenzyl alcohol hydrogenolysis catalyst prepared in this invention has high dispersion of active components, unobstructed pores, and a stable structure. It exhibits not only excellent activity and selectivity but also good strength when used for the hydrogenolysis of dimethylbenzyl alcohol to produce cumene.

[0122] By comparing the results of comparative example 1 and comparative example 1, it can be seen that the addition of lithium carboxymethyl cellulose in the catalyst preparation process can improve the mass transfer performance of the catalyst, weaken the acidity of the catalyst, and improve the stability of the catalyst. The prepared catalyst has good activity, selectivity and strength.

[0123] By comparing the results of comparative example 1 and comparative example 2, it can be seen that the catalyst prepared by the method of extrusion and granulation in the present application has excellent activity.

[0124] By comparing the results of comparative example 1 and comparative example 3, it can be seen that if the amount of lithium carboxymethyl cellulose added is small, the activity, selectivity and strength of the prepared catalyst will decrease to a certain extent.

[0125] By comparing the results of comparative example 1 and comparative example 4, it can be seen that the catalyst particles prepared by the method of cutting in the present application have smaller and more concentrated length, and the activity and selectivity are significantly better than those of the conventional extruded and uncut catalyst.

[0126] By comparing the results of comparative example 1 and comparative examples 5-7, it can be seen that the strength of the catalyst prepared by using basic aluminum sol is significantly reduced; the strength of the catalyst prepared by using neutral aluminum sol is significantly reduced; the selectivity of the catalyst prepared by using aluminum sol prepared by hydrochloric acid method is significantly reduced. The results show that the use of acidic aluminum sol prepared by nitric acid method in the present application and the control of chlorine content < 50 ppm can improve the selectivity of the catalyst and improve the strength of the catalyst.

[0127] The above examples are only specific embodiments of the present application, which are used to illustrate the technical solutions of the present application, but not limited thereto. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can modify or easily think of changes to the technical solutions recorded in the foregoing embodiments within the technical scope disclosed by the present application, or make equivalent replacements to some technical features. These modifications, changes or replacements do not make the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be covered within the protection scope of the present application.

Claims

1. A method for preparing a hydrogenolysis catalyst, characterized in that, include: Provides composite metal compounds containing copper, zinc, and aluminum; The composite metal compound was mixed with lithium carboxymethyl cellulose and molding aids to obtain a mixed powder; The mixed powder was mixed with acidic aluminum sol, and then extruded, dried and calcined to obtain a hydrogenolysis catalyst. The acidic aluminum sol is prepared using the nitric acid method; the chlorine content in the acidic aluminum sol is less than 50 ppm. The mass ratio of the composite metal compound to the lithium carboxymethyl cellulose is 3-7:

1.

2. The preparation method according to claim 1, characterized in that, The lithium carboxymethyl cellulose has a particle size greater than 200 mesh; The concentration of the acidic aluminum sol is 20-40 wt%, the pH value is 1-3, and the particle size of the aluminum sol is 1-10 nm; and / or, The hydrogenolysis catalyst has a diameter of 1.5-3 mm and a length of 1.5-4 mm.

3. The preparation method according to claim 1, characterized in that, In the composite metal compound, the molar ratio of copper, zinc, and aluminum is 1:0.08-0.4:0.6-1.4; The molding aid comprises 2-5% of the weight of the mixed powder; and / or, The mass ratio of the mixed powder to the acidic aluminum sol is 0.8-2:

1.

4. The preparation method according to claim 3, characterized in that, The molding aid is guar gum powder.

5. The preparation method according to claim 1, characterized in that, The preparation method of the composite metal compound includes: Provides mixed solutions containing copper compounds, zinc compounds, and aluminum compounds, as well as precipitant solutions; After the mixed solution and the precipitant solution are precipitated in parallel flow, the mixture is dried and calcined to obtain the composite metal compound.

6. The preparation method according to claim 5, characterized in that, The copper compound is selected from one or more of copper nitrate, copper chloride, and copper sulfate; The zinc compound is selected from one or more of zinc nitrate, zinc chloride, and zinc sulfate; The aluminum compound is selected from one or more of aluminum nitrate, aluminum chloride, and aluminum sulfate; The molar concentration of metal ions in the mixed solution is 1-2 mol / L; and / or, The precipitant solution is a sodium carbonate solution.

7. The preparation method according to claim 6, characterized in that, The sodium carbonate solution has a mass concentration of 10-30%.

8. The preparation method according to any one of claims 1-7, characterized in that, In the steps of extrusion molding, drying and calcination, the extrusion pressure of the extrusion molding is 100-200 N and the screw speed is 10-50 r / min; The drying temperature is 100-120℃, and the time is 4-12 h; and / or, The roasting temperature is 600-800℃ and the time is 2-8 h.

9. The hydrogenolysis catalyst prepared by any one of claims 1-8.

10. The application of the hydrogenolysis catalyst according to claim 9 in the catalytic hydrogenolysis of dimethylbenzyl alcohol to prepare cumene.

11. A method for preparing cumene, comprising: The invention provides hydrocarbon materials containing α,α-dimethylbenzyl alcohol, hydrogen gas, and a hydrogenolysis catalyst, wherein the hydrogenolysis catalyst is the hydrogenolysis catalyst according to claim 9; The hydrogenolysis catalyst is reduced and reacted with the hydrocarbon material containing α,α-dimethylbenzyl alcohol and the hydrogen gas to obtain cumene.

12. The preparation method according to claim 11, characterized in that, The reduction of the hydrogenolysis catalyst includes a step of reduction in a mixed atmosphere of nitrogen and hydrogen.

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