Preparation method of ordered macroporous dimethyl oxalate hydrogenation catalyst

Abstract

The invention discloses a method for preparing a ordered macroporous dimethyl oxalate hydrogenation catalyst. The present invention uses an ordered polystyrene template to regulate a macroporous silicon support, and then a copper solution is regulated by an activating agent to make it into an ordered pore structure. The catalyst of the present invention is composed of a silica support and a copper oxide active component. Copper salts are deposited on a support made from an organosilicon ester to obtain a CuSi catalyst precursor. The precursor is redeposited on the organosilicon ester and dried and calcined to obtain a catalyst. The catalyst composition is measured by oxide mass percentage, and CuO is 10 20%, and the remainder is SiO 2 , and the secondary organosilicon ester accounts for 3 5% of the precursor mass ratio. Although the catalyst of the present invention has a low active component content, it has good low-temperature activity and high selectivity, and the dimethyl oxalate conversion is greater than 99.9%, and the ethylene glycol selectivity is greater than 97%, and the by-products butylene glycol and propylene glycol are selectively low.

Description

Technical Field

[0001] The invention belongs to the technical field of catalyst preparation, and in particular relates to a catalyst for hydrogenating macroporous dimethyl oxalate to ethylene glycol and a preparation method thereof. Background Art

[0002] As an important organic chemical raw material, ethylene glycol is mainly used in the production of polyester fibers, antifreeze, unsaturated polyester resins, plasticizers and surfactants, and has gradually developed into the tobacco, textile and cosmetics industries.

[0003] The main processes for producing EG by the oxalate method include the CO oxidative coupling process to produce dimethyl oxalate (DMO) and the DMO hydrogenation process to produce EG. Among them, the preparation of DMO is already mature and has been successfully industrialized. However, there are still some problems in the DMO hydrogenation process to produce EG: (1) At the reaction temperature, the active copper species with a low H ttig temperature are easily sintered and deactivated, resulting in poor catalyst stability; (2) At high temperatures, the Guerbet reaction is prone to occur to produce the byproduct 1,2-butanediol (1,2 BDO), which is difficult to separate from the product EG, affecting the product quality of EG. Therefore, how to develop an efficient copper-based catalyst based on structural design and synthetic exploration to achieve high selectivity of DMO hydrogenation to EG and reduce or avoid the formation of the byproduct 1,2 BDO is crucial to this process.

[0004] Among the currently published patents for catalysts for the liquid-phase hydrogenation of dimethyl oxalate to ethylene glycol, copper-silicon catalysts are widely used due to their excellent selectivity for hydrogenation of carbon-oxygen double bonds, and all of them utilize vapor-phase hydrogenation. Vapor-phase hydrogenation has a fast reaction rate and 100% conversion, but drawbacks include high reaction temperatures, a high number of byproducts, and a short catalyst life. Yu Jinshan et al. modified a Cu / MS catalyst using ultrasonic-assisted boron impregnation. The results showed that the introduction of an appropriate amount of boron species not only improved the EG selectivity and stability of the Cu / MS catalyst, but also successfully suppressed the formation of the byproduct 1,2-BDO at the basic sites by introducing weakly acidic boron oxide. Song et al. reduced the basic sites of the copper-based catalyst by adding an aluminum component to the catalyst, inhibiting the formation of C3-C4OH, while also improving EtOH selectivity. Furthermore, when EG replaced DMO as the feedstock, C3-C4OH formation was significantly suppressed. Patent CN202011605298 discloses a method and apparatus for preparing ethylene glycol catalyst by liquid-phase hydrogenation of dimethyl oxalate. Soluble copper salt is co-precipitated with sodium silicate, and a copper-silicon catalyst is obtained through aging, washing, drying and calcination. The copper-silicon catalyst prepared by this invention is suitable for liquid-phase hydrogenation of dimethyl oxalate, has high activity, and the selectivity of by-products 1,2-butanediol and 1,2-propylene glycol is suppressed. However, the catalyst is prone to produce methyl glycolate.

[0005] However, the above methods have only achieved some results in the experimental stage and have not yet been realized in industrial production. Therefore, at this stage, a preparation technology with simple operation and good repeatability is needed to solve the side reactions that are prone to occur at high temperatures. Summary of the Invention

[0006] In view of the above shortcomings, the purpose of the present invention is to develop a method for preparing an ordered macroporous dimethyl oxalate hydrogenation catalyst to ethylene glycol, which has the advantages of high conversion rate, high EG selectivity, low butanediol and propylene glycol selectivity and long service life.

[0007] A method for preparing an ordered macroporous dimethyl oxalate hydrogenation catalyst uses an ordered polystyrene template to create a macroporous silica support. An active agent is then used to adjust a copper solution to create an ordered pore structure. The catalyst comprises a silica support and a copper active component. A copper salt is deposited on an organosilicon ester support by steaming to obtain a CuSi catalyst precursor. The precursor is then deposited with an organosilicon ester, followed by drying and calcining to obtain the catalyst. The catalyst comprises, by oxide mass percentage, 10-20% CuO, with the remainder being SiO2. The secondary organosilicon ester accounts for 3-5% of the precursor.

[0008] The method for preparing an ordered macroporous dimethyl oxalate hydrogenation catalyst is characterized in that the silicon source of the silica carrier is an organic silicon ester; and the copper source of the copper active component is one of copper nitrate, copper acetate and copper glycinate.

[0009] The method for preparing an ordered macroporous dimethyl oxalate hydrogenation catalyst is characterized by comprising the following steps:

[0010] (1) Preparation of ordered polystyrene: After mixing a certain amount of styrene and divinylbenzene, add Span-80 and azobisisobutylamine hydrochloride while stirring. Slowly add deionized water under vigorous stirring and continue stirring for 30 minutes. Then polymerize at 65°C for 24 hours and dry at 60°C.

[0011] (2) According to the catalyst content ratio, weigh a certain amount of copper salt and activator, mix them in ethanol, and stir at 30°C for 15 minutes to mix evenly;

[0012] (3) adding the organosilicon ester to deionized water and stirring evenly, then adding the polystyrene obtained in step (1) and adding ammonia water and stirring for 30 minutes, then adding the copper mixture in step (2) and continuing to stir for 4 hours, and evaporating and depositing at a temperature of 80-100°C to obtain a solid;

[0013] (4) Methanol and water were added to the solid obtained by evaporation and deposition in step (3), and ultrasonic treatment was performed for 0.5 h to obtain a uniform suspension, and then organic silicone ester and ammonia water were added and stirred for 0.5 h to 1 h;

[0014] (5) The suspension obtained in step (4) was evaporated to dryness at 90°C and calcined at 400-500°C for 3-5h to obtain an ordered macroporous dimethyl oxalate hydrogenation catalyst.

[0015] The active agent is one of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, benzimidazole and 2-methylimidazole; the secondary organic silicon ester can be the same or different; the organic silicon ester is methyl orthosilicate or ethyl orthosilicate; the mass ratio of the copper salt:active agent:ethanol is 1:1-1.3:10-20, the mass ratio of the organic silicon ester:ammonia water is 1:0.36-0.6, and the mass of the polystyrene is 0.3-0.6 times the mass of the silicon source. The catalyst prepared by the method has a low operating temperature of 150-170°C and a catalyst pore diameter of 45-65nm.

[0016] The beneficial effects of the present invention are:

[0017] The catalyst prepared by the present invention has high activity and EG selectivity, especially low content of butanediol and propylene glycol, which is conducive to separation. In addition, no transition metal additives other than the active components are added in the present invention, which reduces costs. The present invention uses an organic silicon source and a self-made ordered polystyrene template to perform hydrolysis and deposition to synthesize an ordered macroporous silica precursor. Different types of copper salts interact with another template agent, benzimidazole, to order the pore structure, which is conducive to the passage of ethylene glycol molecules on the catalyst. In addition, existing inventions all have large specific surfaces. The present invention uses batch addition of silicon sources in the catalyst synthesis process to effectively control the specific surface area. A secondary organic silicon ester monolayer is deposited on the surface of the CuSi precursor, which is conducive to reducing the reaction depth and reducing the production of higher alcohols and polymers by side reactions. It effectively improves the surface properties of the catalyst, reduces the adhesion of polymers to the catalyst during long-cycle reactions, reduces the catalyst poisoning rate, and greatly improves the life and selectivity of the catalyst. DETAILED DESCRIPTION

[0018] The present invention is further described in detail below with reference to the embodiments so that those skilled in the art can implement the invention with reference to the description. Example 1

[0019] Preparation of ordered polystyrene: After mixing 40 mL of styrene and 10 mL of divinylbenzene, add 7.5 g of Span-80 and 0.85 g of azobisisobutylamine hydrochloride while stirring. Slowly add deionized water while stirring vigorously, continue stirring for 30 minutes, then polymerize at 65°C for 24 hours, and dry at 60°C for use.

[0020] 7.5 g of copper nitrate, 9.75 g of benzimidazole and 150 g of ethanol were weighed and mixed, stirred at 30 ° C for 15 min to obtain liquid I; 42.6 g of tetraethyl orthosilicate was added to 60 g of deionized water and stirred evenly, then 21.1 g of polystyrene was added, and then 21.1 g of ammonia was added and stirred for 30 min, and then liquid I was added and stirred for 4 h. The solid was evaporated and precipitated at 80 ° C. 90 g of methanol and 10 g of water were added to the solid and ultrasonically treated for 0.5 h. Then 1.32 g of tetraethyl orthosilicate and 0.79 g of ammonia were added and stirred for 1 h. The catalyst was evaporated to dryness at 90 ° C and calcined at 400 ° C for 5 h to obtain the desired catalyst A, of which CuO accounted for 20% and the secondary added organic silicone accounted for 3%. The pore size was 55 nm and the specific surface area was 268 m 2 / g. Example 2

[0021] Preparation of ordered polystyrene: After mixing 40 mL of styrene and 10 mL of divinylbenzene, 6.5 g of Span-80 and 0.95 g of azobisisobutylamine hydrochloride were added while stirring. Deionized water was slowly added under vigorous stirring and stirring was continued for 30 minutes. The mixture was then polymerized at 65°C for 24 hours and dried at 60°C for later use.

[0022] Weigh 6.19g of copper acetate, 9g of benzimidazole and 112g of ethanol, mix them, stir at 30℃ for 15min and mix them evenly to obtain liquid I; add 42.1g of tetraethyl orthosilicate to 61g of deionized water, stir evenly, add 17.5g of polystyrene, add 17.5g of ammonia water and stir for 30min, then add liquid I and continue stirring for 4h, evaporate and precipitate at 100℃ to obtain a solid, add 90g of methanol and 10g of water to the solid and ultrasonicate for 0.5h, then add 1.75g ​​of tetraethyl orthosilicate and 0.72g of ammonia water and stir for 1h, then evaporate to dryness at 90℃ and calcine at 450℃ for 4h to obtain the desired catalyst B, of which CuO accounts for 15% and the secondary added organic silicone ester accounts for 4%. Its pore size is 48nm and the specific surface area is 275m 2 / g. Example 3

[0023] Preparation of ordered polystyrene: After mixing 40 mL of styrene and 10 mL of divinylbenzene, add 7.5 g of Span-80 and 0.75 g of azobisisobutylamine hydrochloride while stirring. Slowly add deionized water while stirring vigorously, continue stirring for 30 minutes, then polymerize at 65°C for 24 hours, and dry at 60°C for use.

[0024] 6.56 g of copper glycinate, 8.25 g of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide and 75 g of ethanol were weighed and mixed, stirred at 30 ° C for 15 min to obtain liquid I; 84 g of tetraethyl orthosilicate was added to 121 g of deionized water and stirred evenly, then 25.2 g of polystyrene was added, and then 30.2 g of ammonia was added and stirred for 30 min, and then liquid I was added and stirred for 4 h. The solid was evaporated and precipitated at 90 ° C. 90 g of methanol and 10 g of water were added to the solid and ultrasonically treated for 0.5 h. Then 4.42 g of tetraethyl orthosilicate and 12.2 g of ammonia were added and stirred for 1 h. The catalyst was evaporated to dryness at 90 ° C and calcined at 500 ° C for 3 h to obtain the desired catalyst C, in which CuO accounted for 10% and the secondary added organic silicone accounted for 5%. The pore size was 65 nm and the specific surface area was 255 m 2 / g. Example 4

[0025] Preparation of ordered polystyrene: After mixing 40 mL of styrene and 10 mL of divinylbenzene, add 7.5 g of Span-80 and 0.85 g of azobisisobutylamine hydrochloride while stirring. Slowly add deionized water while stirring vigorously, continue stirring for 30 minutes, then polymerize at 65°C for 24 hours, and dry at 60°C for use.

[0026] 7.5 g of copper nitrate, 9.75 g of 2-methylimidazole and 150 g of ethanol were weighed and mixed, stirred at 30 ° C for 15 min to obtain liquid I; 41.7 g of tetraethyl orthosilicate was added to 50 g of deionized water and stirred evenly, then 21.1 g of polystyrene was added, and then 15.0 g of ammonia was added and stirred for 30 min, and then liquid I was added and stirred for 4 h. The solid was evaporated and precipitated at 90 ° C. 90 g of methanol and 10 g of water were added to the solid and ultrasonically treated for 0.5 h. Then 1.56 g of methyl orthosilicate and 0.79 g of ammonia were added and stirred for 1 h. The catalyst was evaporated to dryness at 90 ° C and calcined at 400 ° C for 5 h to obtain the desired catalyst D, of which CuO accounted for 20% and the secondary added organic silicone accounted for 5%. The pore size was 56 nm and the specific surface area was 265 m 2 / g. Example 5

[0027] Preparation of ordered polystyrene: After mixing 40 mL of styrene and 10 mL of divinylbenzene, 6.5 g of Span-80 and 0.95 g of azobisisobutylamine hydrochloride were added while stirring. Deionized water was slowly added under vigorous stirring and stirring was continued for 30 minutes. The mixture was then polymerized at 65°C for 24 hours and dried at 60°C for later use.

[0028] 6.56 g of copper glycinate, 9 g of benzimidazole and 112 g of ethanol were weighed and mixed, stirred at 30 ° C for 15 min to obtain liquid I; 29.9 g of methyl orthosilicate was added to 51 g of deionized water and stirred evenly, then 17.5 g of polystyrene was added, and then 17.5 g of ammonia was added and stirred for 30 min, and then liquid I was added and stirred for 4 h. The solid was evaporated and deposited at 100 ° C. 90 g of methanol and 10 g of water were added to the solid and ultrasonically treated for 0.5 h. Then 1.25 g of methyl orthosilicate and 0.62 g of ammonia were added and stirred for 1 h. The catalyst was evaporated to dryness at 90 ° C and calcined at 450 ° C for 4 h to obtain the desired catalyst E, in which CuO accounted for 15% and the secondary added organic silicone accounted for 4%. The pore size was 60 nm and the specific surface area was 277 m 2 / g. Example 6

[0029] Preparation of ordered polystyrene: After mixing 40 mL of styrene and 10 mL of divinylbenzene, add 7.5 g of Span-80 and 0.85 g of azobisisobutylamine hydrochloride while stirring. Slowly add deionized water while stirring vigorously, continue stirring for 30 minutes, then polymerize at 65°C for 24 hours, and dry at 60°C for use.

[0030] 7.5 g of copper nitrate, 9.75 g of benzimidazole and 150 g of ethanol were weighed and mixed, stirred at 30 ° C for 15 min to obtain liquid I; 30.3 g of methyl orthosilicate was added to 45 g of deionized water and stirred evenly, then 21.1 g of polystyrene was added, and then 18.2 g of ammonia was added and stirred for 30 min, and then liquid I was added and stirred for 4 h. The solid was evaporated and precipitated at 80 ° C. 90 g of methanol and 10 g of water were added to the solid and ultrasonically treated for 0.5 h. Then 1.32 g of ethyl orthosilicate and 0.79 g of ammonia were added and stirred for 1 h. The catalyst was evaporated to dryness at 90 ° C and calcined at 400 ° C for 5 h to obtain the desired catalyst F, of which CuO accounted for 20% and the secondary added organic silicone accounted for 3%. The pore size was 45 nm and the specific surface area was 285 m 2 / g.

[0031] Comparative Example 1

[0032] Weigh 7.5 g of copper nitrate, dissolve it in 50 g of deionized water, then add 30 mL of ammonia water, stir at 30 ° C for 15 min to mix evenly to obtain liquid I; add 39.6 g of methyl orthosilicate into 60 g of deionized water and stir evenly, then add 18.2 g of ammonia water and stir for 30 min, then add liquid I and continue stirring for 4 h, evaporate and precipitate at 90 ° C to obtain a solid, calcine at 400 ° C for 5 h to obtain the desired catalyst A-1, of which CuO accounts for 20%, its pore size is 8.7 nm, and its specific surface area is 365 m 2 / g.

[0033] Comparative Example 2

[0034] Weigh 6.19 g of copper acetate, dissolve it in 50 g of deionized water, then add 30 mL of ammonia water, stir at 30 ° C for 15 min to mix evenly to obtain I; add 43.8 g of ethyl orthosilicate to 61 g of deionized water, stir evenly, add 17.5 g of polystyrene, add 17.5 g of ammonia water, stir for 30 min, then add I solution and continue stirring for 4 h, evaporate and precipitate at 90 ° C to obtain a solid, calcine at 450 ° C for 4 h to obtain the desired catalyst B-1, of which CuO accounts for 15%, its pore size is 14.6 nm, and its specific surface area is 335 m 2 / g.

[0035] Comparative Example 3

[0036] Weigh 7.5g of copper nitrate, dissolve it in 50g of deionized water, then add 30mL of ammonia water, stir at 30℃ for 15min to mix evenly to obtain Ⅰ; add 41.7g of ethyl orthosilicate into 50g of deionized water, stir evenly, add 15.0g of ammonia water and stir for 30min, then add Ⅰ solution and continue stirring for 4h, evaporate and precipitate at 90℃ to obtain a solid, add 90g of methanol and 10g of water to the solid and ultrasonicate for 0.5h, then add 1.56g of methyl orthosilicate and 0.79g of ammonia water and stir for 1h, then evaporate to dryness at 90℃, and calcine at 400℃ for 5h to obtain the desired catalyst A-2, of which CuO accounts for 20% and the secondary added organic silicone ester accounts for 5%. Its pore size is 9.8nm and the specific surface area is 295m 2 / g.

[0037] The evaluation method of the copper-based catalyst for dimethyl oxalate hydrogenation of Examples 1-6 and Comparative Examples 1-3 is as follows: a certain amount of 20-40 mesh catalyst particles are weighed and reduced in a hydrogen atmosphere at 220°C for 12 h with a hydrogen space velocity of 1000 h / min. -1 , reduction pressure 1.0MPa, after the reduction is completed, wait for the system to drop to 150-170℃ and then slowly increase the system pressure to 2.5Mpa, a 12.5% ​​mass fraction of dimethyl oxalate methanol solution is introduced into the vaporization chamber and mixed with hydrogen, the hydrogen-ester ratio is 100, the liquid-space velocity is 1.0h-1, and a certain reaction temperature is controlled. The results of dimethyl oxalate hydrogenation are listed in Table 1.

[0038] Table 1 Results of dimethyl oxalate hydrogenation reaction

[0039]

[0040] From the analysis of Table 1, it can be seen that the catalyst prepared in the embodiment of the present invention has a conversion rate of greater than 99.9% and a target product selectivity of greater than 97% in the dimethyl oxalate hydrogenation reaction under mild conditions; while other patents or literature reports have achieved the same catalytic performance, under these conditions, although the conversion rate is the same, but the selectivity for butanediol and propylene glycol is also higher, indicating that the catalyst prepared in the present invention has good ethylene glycol selectivity and the function of inhibiting the formation of C3-C4OH. The catalyst made by the present invention has an ordered macroporous structure.

[0041] The above-described embodiments are merely preferred embodiments for fully illustrating the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are within the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

Claims

1. A method for preparing an ordered macroporous dimethyl oxalate hydrogenation catalyst, characterized in that: The preparation method comprises: using ordered polystyrene as a template to control a macroporous silicon support, then adjusting a copper solution with an active agent to form an ordered pore structure; the prepared catalyst comprises a silica support and a copper active component; depositing a copper salt on a support made of an organic silicon ester by steaming to obtain a CuSi catalyst precursor; and then depositing a secondary organic silicon ester on the precursor, drying and calcining the precursor to obtain a catalyst. The catalyst composition, in terms of oxide mass percentage, is 10-20% CuO, with the remainder being SiO2, and the secondary organic silicon ester accounting for 3-5% of the precursor by mass. The catalyst preparation method specifically comprises the following steps: (1) Preparation of ordered polystyrene: After mixing a certain amount of styrene and divinylbenzene, add Span-80 and azobisisobutylamidine hydrochloride while stirring. Slowly add deionized water under vigorous stirring and continue stirring for 30 minutes. Then polymerize at 65°C for 24 hours and dry at 60°C. (2) According to the catalyst content ratio, a certain amount of copper salt and activator are weighed, mixed in ethanol, and stirred at 30°C for 15 minutes to mix evenly; the activator is one of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, benzimidazole and 2-methylimidazole; (3) adding the organosilicon ester to deionized water and stirring evenly, then adding the polystyrene obtained in step (1), adding ammonia water and stirring for 30 minutes, then adding the copper mixture in step (2) and continuing to stir for 4 hours, and evaporating and depositing at a temperature of 80-100°C to obtain a solid; (4) Methanol and water were added to the solid obtained by evaporation and deposition in step (3), and ultrasonic treatment was performed for 0.5 h to obtain a uniform suspension, and then secondary organosilicon ester and ammonia water were added and stirred for 0.5 h to 1 h; (5) The suspension obtained in step (4) was evaporated to dryness at 90°C and calcined at 400-500°C for 3-5h to obtain an ordered macroporous dimethyl oxalate hydrogenation catalyst.

2. The method for preparing an ordered macroporous dimethyl oxalate hydrogenation catalyst according to claim 1, wherein: The copper active component copper salt is one of copper nitrate, copper acetate and copper glycinate.

3. The method for preparing an ordered macroporous dimethyl oxalate hydrogenation catalyst according to claim 1, wherein: The organic silicone ester is methyl orthosilicate or ethyl orthosilicate.

4. The method for preparing an ordered macroporous dimethyl oxalate hydrogenation catalyst according to claim 1, wherein: The mass ratio of copper salt: active agent: ethanol in step (2) is 1:1-1.3:10-20, the mass ratio of organosilicon ester: ammonia water in step (3) is 1:0.36-0.6, and the amount of polystyrene used is 0.3-0.6 times the mass of the organosilicon ester.

5. The method for preparing an ordered macroporous dimethyl oxalate hydrogenation catalyst according to claim 1, wherein: The catalyst prepared by the method has an operating temperature of 150-170° C. and a catalyst pore diameter of 45-65 nm.

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