Modified mesoporous carbon catalyst with ultrahigh specific surface area, preparation method of modified mesoporous carbon catalyst and application of modified mesoporous carbon catalyst in ketone alcohol condensation reaction

Abstract

The invention relates to the field of fine chemical engineering, and discloses a modified mesoporous carbon catalyst with an ultrahigh specific surface area, a preparation method of the modified mesoporous carbon catalyst and application of the modified mesoporous carbon catalyst in ketoalcohol condensation reaction. The modified mesoporous carbon catalyst with the ultrahigh specific surface area is obtained by acidizing mesoporous carbon with the ultrahigh specific surface area, and the surface acid density of the modified mesoporous carbon catalyst with the ultrahigh specific surface area is 1.3-4 mmol / g. When the modified mesoporous carbon catalyst with the ultrahigh specific surface area is used for condensation reaction of acetone and ethylene glycol, higher yield of 2, 2-dimethyl-1, 3-dioxolane can be obtained.

Description

Technical Field

[0001] The invention relates to the field of fine chemicals, and in particular to a modified ultra-high specific surface area mesoporous carbon catalyst, a preparation method thereof, and an application thereof in a ketone-alcohol condensation reaction. Background Art

[0002] Ketal (aldehyde) is an important type of carbonyl condensation compound, which is the product of the condensation of carbonyl compounds and diols under acidic conditions. It is usually used in the synthesis of steroids and sugars, carbonyl protection of organic compounds, paints, and as an intermediate and target product in the pharmaceutical industry; because ketal compounds have floral, fruity or special aromas, and have long-lasting fragrance and stable chemical properties, they are also often used in spices, such as flavoring and fixing of alcoholic beverages, soft drinks, ice cream, cosmetics, etc.; at the same time, ketal spices can also be used to prepare edible flavors such as chicken flavor, meat flavor, and cream. Therefore, ketal has great market development potential and has attracted the attention of many researchers. Among them, 2,2-dimethyl-1,3-dioxolane is an important intermediate in the new process of petrochemical product ethylene glycol. The 1,3-dioxolane compounds can be used as solvents in industry to replace commonly used industrial solvents such as dichloromethane, dichloroethane and butanone, and can also be used as solvents for polymers (Kirk-Othmer Encydopedia of Chemical Technology, John Wllley, Sons, Now Pork, Vol. 12: page 710).

[0003] There are many methods for synthesizing ketals, among which the most commonly used is to condense ketone compounds with alcohol compounds in the presence of a catalyst. In the prior art, when preparing 2,2-dimethyl-1,3-dioxolane, the catalyst used is mainly a protonic acid catalyst (including inorganic acid and organic acid) or a Lewis acid catalyst. When acid catalysts catalyze cyclization reactions, they have the disadvantages of easy corrosion of equipment, large dosage, difficult separation of products, low product selectivity, and easy environmental pollution. Therefore, it is still of positive significance to seek ketal catalysts that have strong catalytic activity, high selectivity, and are easy to separate from the reaction system. Ketal catalysts for multiphase reactions are currently a relatively active research field. At present, the catalysts that have been reported to replace concentrated sulfuric acid include strong acid ion exchange resins, heteropoly acids, ionic liquids, solid superacids, etc., and have achieved good results. Among them, strong acid ion exchange resins have attracted widespread attention due to their advantages such as insolubility in the reaction system, good stability, high selectivity, low cost, and easy separation. Strong acid ion exchange resin is a polymer material containing acidic functional active ingredients, which has strong catalytic ability for esterification, aldehyde-ketone condensation, etherification, etc. However, the acid strength of strong acid cation exchange resin acid is weaker than that of sulfuric acid. When used alone as a ketal catalyst, the reaction rate is slower than that of concentrated sulfuric acid. For researchers, developing excellent ketal catalysts, improving reaction efficiency, and inhibiting the formation of by-products are important future work directions. Summary of the invention

[0004] The purpose of the present invention is to overcome the problems of poor catalyst efficiency and low target product yield in the production process of 2,2-dimethyl-1,3-dioxolane in the prior art, and to provide a modified ultra-high specific surface area mesoporous carbon catalyst and a preparation method thereof, as well as an application in a ketone-alcohol condensation reaction. The modified ultra-high specific surface area mesoporous carbon catalyst is used for the condensation reaction of acetone and ethylene glycol, so as to obtain a higher 2,2-dimethyl-1,3-dioxolane yield.

[0005] In order to achieve the above-mentioned purpose, the first aspect of the present invention provides a modified ultra-high specific surface area mesoporous carbon catalyst, wherein the modified ultra-high specific surface area mesoporous carbon catalyst is obtained by acidifying ultra-high specific surface area mesoporous carbon, and the surface acid density of the modified ultra-high specific surface area mesoporous carbon catalyst is 1.3-4 mmol / g.

[0006] The second aspect of the present invention provides a method for preparing a modified ultra-high specific surface area mesoporous carbon catalyst, wherein the preparation method comprises:

[0007] (1) contacting the ultra-high specific surface area mesoporous carbon with concentrated sulfuric acid under pressure to react to obtain a solid product;

[0008] (2) washing and drying the solid product to obtain a modified ultra-high specific surface area mesoporous carbon catalyst;

[0009] Wherein, the weight ratio of the ultra-high specific surface area mesoporous carbon to the concentrated sulfuric acid is 1:(0.2-10).

[0010] The third aspect of the present invention provides a modified ultra-high specific surface area mesoporous carbon catalyst prepared by the aforementioned preparation method.

[0011] A fourth aspect of the present invention provides an application of the aforementioned modified ultra-high specific surface area mesoporous carbon catalyst in a ketone-alcohol condensation reaction.

[0012] The fifth aspect of the present invention provides a method for preparing 2,2-dimethyl-1,3-dioxolane, wherein the method comprises: in the presence of a water-carrying agent, contacting a modified ultra-high specific surface area mesoporous carbon catalyst, acetone and ethylene glycol to carry out a condensation reaction to prepare 2,2-dimethyl-1,3-dioxolane;

[0013] Wherein, the modified ultra-high specific surface area mesoporous carbon catalyst is the modified ultra-high specific surface area mesoporous carbon catalyst described above.

[0014] Through the above technical solution, the technical solution of the present invention has the following advantages:

[0015] (1) The carrier and active components of the modified ultra-high specific surface area mesoporous carbon catalyst provided by the present invention are both inorganic materials, which are stable in nature, have good high temperature resistance, and are not easy to swell during the reaction.

[0016] (2) The modified ultra-high specific surface area mesoporous carbon catalyst provided by the present invention has a high surface acid density, a high catalyst catalytic efficiency, and a high yield of the target product.

[0017] (3) The raw materials of the modified ultra-high specific surface area mesoporous carbon catalyst provided by the present invention are easy to obtain, the preparation method is simple, the conditions are easy to control, and the product has good reproducibility.

[0018] (4) When the catalyst provided by the present invention is used to synthesize 2,2-dimethyl-1,3-dioxolane, the process conditions are mild and the requirements for the reaction device are not high.

[0019] Other features and advantages of the present invention will be described in detail in the following detailed description. DETAILED DESCRIPTION

[0020] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0021] As mentioned above, the first aspect of the present invention provides a modified ultra-high specific surface area mesoporous carbon catalyst, wherein the modified ultra-high specific surface area mesoporous carbon catalyst is obtained by acidifying ultra-high specific surface area mesoporous carbon, and the surface acid density of the modified ultra-high specific surface area mesoporous carbon catalyst is 1.3-4 mmol / g.

[0022] The inventors of the present invention have found that in the prior art, the catalysts used for ketone-alcohol condensation reactions are divided into two categories: homogeneous and heterogeneous. Among them, homogeneous catalysts mainly include inorganic acid solutions and organic acids, and heterogeneous catalysts mainly include solid acid catalysts and supported catalysts. The advantages of homogeneous catalysts are low price and good catalytic activity, but they are gradually eliminated due to defects such as difficulty in separating products from catalysts, more side reactions, and easy corrosion of equipment. Although heterogeneous catalysts solve the problems of difficult product separation and serious equipment corrosion, they are rarely used in industrial production due to shortcomings such as poor catalytic stability and low product yield. Compared with the above catalysts, using ultra-high specific surface area mesoporous carbon as a catalyst to produce ketal products is a better choice. Resin catalysts have the advantages of high selectivity, low cost and easy separation, but the acid strength of strongly acidic cation exchange resin acid is weaker than sulfuric acid. When used alone as a condensation reaction catalyst, the reaction rate is slower than concentrated sulfuric acid. If concentrated sulfuric acid can be immobilized on a certain material by an appropriate method, it can be ensured that the obtained solid catalyst has strong acidity and is suitable for condensation reactions. The selected solid support material should have a large specific surface area and pore volume to accommodate more active groups. Ultra-high specific surface area mesoporous carbon materials are a new type of non-silicon-based mesoporous materials with ultra-high specific surface area, huge pore volume and large pore size. Compared with pure silicon mesoporous materials, mesoporous carbon materials exhibit special properties, have higher specific surface area and pore volume, are simple to synthesize, easy to operate, and have no physiological toxicity.

[0023] The inventors of the present invention found during the development of ketal catalysts that there are no hydroxyl groups on the surface of carbon materials and that they are not suitable for modification with halosulfonic acid. If concentrated sulfuric acid is used to modify ultra-high specific surface area mesoporous carbon, a ketal catalyst with excellent performance can be obtained. On the one hand, the concentrated sulfuric acid molecules adhere to the pores of the mesoporous carbon material and are not easy to fall off during the reaction, and have good stability. On the other hand, the modified ultra-high specific surface area mesoporous carbon catalyst has a higher acid density, which can significantly improve the catalytic efficiency of the catalyst. Based on the above reasons, the modified ultra-high specific surface area mesoporous carbon catalyst can exhibit good catalytic activity and target product yield when used in ketone-alcohol condensation reactions.

[0024] According to the present invention, preferably, the surface acid density of the modified ultra-high specific surface area mesoporous carbon catalyst is 1.8-3.5 mmol / g. More preferably, the surface acid density of the modified ultra-high specific surface area mesoporous carbon catalyst is 2.5-3.2 mmol / g. In the present invention, if the modified ultra-high specific surface area mesoporous carbon catalyst has the aforementioned specific surface acid density, the prepared catalyst can have better catalytic activity and target product yield when used for ketone-alcohol condensation reaction.

[0025] According to the present invention, the specific surface area of ​​the ultra-high specific surface area mesoporous carbon material carrier is 2500-3500m 2 / g, pore volume is 1-2.5cm 3 / g, and an average pore size of 10-14nm; preferably, the specific surface area of ​​the ultra-high specific surface area mesoporous carbon material carrier is 2800-3000m 2 / g, pore volume is 2-2.5cm 3 / g, and the average pore size is 13-14nm. In the present invention, the ultra-high specific surface area mesoporous carbon material specified above is used, and the high specific surface area and large pore volume of the mesoporous carbon material can be used to achieve uniform dispersion of strong acid active sites.

[0026] According to the present invention, the specific surface area of ​​the modified ultra-high specific surface area mesoporous carbon catalyst is 2200-2900m 2 / g, pore volume is 1.5-1.9cm 3 / g, and the average pore size is 9-13nm; preferably, the specific surface area of ​​the modified ultra-high specific surface area mesoporous carbon catalyst is 2500-2800m 2 / g, pore volume is 1.6-1.8cm 3 / g, and the average pore size is 10-12nm.

[0027] The second aspect of the present invention provides a method for preparing a modified ultra-high specific surface area mesoporous carbon catalyst, wherein the preparation method comprises:

[0028] (1) contacting the ultra-high specific surface area mesoporous carbon with concentrated sulfuric acid under pressure to react to obtain a solid product;

[0029] (2) washing and drying the solid product to obtain a modified ultra-high specific surface area mesoporous carbon catalyst;

[0030] Wherein, the weight ratio of the ultra-high specific surface area mesoporous carbon to the concentrated sulfuric acid is 1:(0.2-10).

[0031] According to the present invention, preferably, the weight ratio of the ultra-high specific surface area mesoporous carbon to the concentrated sulfuric acid is 1:(0.5-5); more preferably, the weight ratio of the ultra-high specific surface area mesoporous carbon to the concentrated sulfuric acid is 1:(1-3).

[0032] According to the present invention, the contacting conditions include: a temperature of 80-180° C., preferably 100-150° C.; and a contacting time of 4-30 hours, preferably 8-20 hours.

[0033] According to the present invention, the pressurization conditions include: the pressure is 0.2-10Mpa, preferably 0.5-5Mpa.

[0034] And / or, the specific surface area of ​​the ultra-high specific surface area mesoporous carbon material carrier is 2500-3500m 2 / g, pore volume is 1-2.5cm 3 / g, average pore size is 10-14nm;

[0035] Preferably, the specific surface area of ​​the ultra-high specific surface area mesoporous carbon material carrier is 2800-3000m 2 / g, pore volume is 2-2.5cm 3 / g, and the average pore size is 13-14nm.

[0036] According to the present invention, preferably, the contact between the ultra-high specific surface area mesoporous carbon and the concentrated sulfuric acid is carried out in an autoclave, and rapid stirring can be performed during the contact between the ultra-high specific surface area mesoporous carbon and the concentrated sulfuric acid to improve the contact efficiency and uniformity. In the present invention, the conditions for the rapid stirring are not specifically limited, and preferably, the stirring rate is 200-800 rpm.

[0037] According to the present invention, the washing conditions include: the washing medium is preferably distilled water; the washing medium temperature can be 60-100°C, preferably 80-95°C; the weight ratio of distilled water to solid product can be 5-30, preferably 10-20; the number of washing times can be 3-12 times, preferably 5-10 times.

[0038] According to the present invention, the drying conditions include: the temperature can be 60-120° C., preferably 80-100° C.; the time can be 3-16 hours, preferably 5-12 hours.

[0039] The third aspect of the present invention provides a modified ultra-high specific surface area mesoporous carbon catalyst prepared by the aforementioned preparation method.

[0040] A fourth aspect of the present invention provides an application of the aforementioned modified ultra-high specific surface area mesoporous carbon catalyst in a ketone-alcohol condensation reaction.

[0041] The fifth aspect of the present invention provides a method for preparing 2,2-dimethyl-1,3-dioxolane, wherein the method comprises: in the presence of a water-carrying agent, contacting a modified ultra-high specific surface area mesoporous carbon catalyst, acetone and ethylene glycol to carry out a condensation reaction to prepare 2,2-dimethyl-1,3-dioxolane;

[0042] Wherein, the modified ultra-high specific surface area mesoporous carbon catalyst is the modified ultra-high specific surface area mesoporous carbon catalyst described above.

[0043] According to the present invention, the water-carrying agent is preferably cyclohexane or benzene.

[0044] According to the present invention, the weight ratio of the modified ultra-high specific surface area mesoporous carbon catalyst, the water-carrying agent, acetone and ethylene glycol is 1: (8-50): (10-60): (20-100).

[0045] According to the present invention, the conditions of the condensation reaction include: temperature of 60-100° C., preferably 70-90° C.; time of 0.5-10 h, preferably 1-6 h.

[0046] The present invention will be described in detail below through examples.

[0047] In the following examples and comparative examples:

[0048] (1) The pore structure parameter analysis of the mesoporous carbon samples was carried out on an ASAP2020-M+C adsorption instrument purchased from Micromeritics, USA. The samples were vacuum degassed at 40°C for 4 hours before measurement. The specific surface area of ​​the samples was calculated using the BET method, and the pore volume was calculated using the BJH model.

[0049] (2) The amount of acid on the catalyst surface was determined by neutralization titration.

[0050] (3) The drying oven was manufactured by Shanghai Yiheng Scientific Instrument Co., Ltd., model DHG-9030A.

[0051] (4) The ultra-high specific surface area mesoporous carbon material was purchased from Nanjing Xianfeng Nanomaterial Technology Co., Ltd.; the reagents used in the examples and comparative examples were purchased from Sinopharm Chemical Reagent Co., Ltd., and the reagent purity was analytical grade.

[0052] Example 1

[0053] (1) Preparation of modified ultra-high specific surface area mesoporous carbon catalyst

[0054] 5 g of ultra-high specific surface area mesoporous carbon (specific surface area of ​​3000 m 2 / g, pore volume 2.0cm 3 / g, average pore size of 14nm) and 12g concentrated sulfuric acid were mixed, transferred to a 100ml autoclave, heated to 120°C, filled with high-purity nitrogen and maintained at a pressure of 3Mpa, and stirred for 15 hours at a stirring rate of 600 rpm. After cooling and unloading the pressure, the solid product was taken out and washed 8 times with 95°C distilled water. Dry in air at 90°C for 10 hours to obtain a modified ultra-high specific surface area mesoporous carbon catalyst A.

[0055] Results The specific surface area of ​​the modified ultra-high specific surface area mesoporous carbon catalyst A is 2640 m 2 / g, pore volume 1.72cm 3 / g, and the average pore size is 11.2nm.

[0056] In addition, the acid density of the modified ultra-high specific surface area mesoporous carbon catalyst A is 3.0 mmol / g.

[0057] (2) Catalyst reaction performance evaluation

[0058] Add 11.6g acetone and 18.6g ethylene glycol, 10g cyclohexane with water and 0.4g modified ultra-high specific surface area mesoporous carbon catalyst A to a 100ml three-necked flask, and install a thermometer, a water separator and a reflux condenser. Heat and reflux water until almost no water is separated. After the reaction is completed, the reaction system is cooled to room temperature and the water layer is released. Filter the reaction solution, recover the catalyst, wash the filtrate with saturated brine and distilled water in turn, combine the organic layers, dry with anhydrous magnesium sulfate, first distill and recover cyclohexane (boiling point 80-81°C), then distill and collect the product 2,2-dimethyl-1,3-dioxolane (boiling point 92-93°C), and weigh and calculate the yield.

[0059] As a result, the yield of 2,2-dimethyl-1,3-dioxolane was 96.0%.

[0060] Example 2

[0061] (1) Preparation of modified ultra-high specific surface area mesoporous carbon catalyst

[0062] 5 g of ultra-high specific surface area mesoporous carbon (specific surface area of ​​3000 m 2 / g, pore volume 2.0cm 3 / g, average pore size of 14nm) and 15g concentrated sulfuric acid were mixed, transferred to a 100ml autoclave, heated to 100°C, filled with high-purity nitrogen and maintained at a pressure of 1Mpa, and stirred for 8 hours at a stirring rate of 800 rpm. After cooling and depressurizing, the solid product was taken out and washed 10 times with 80°C distilled water. Dry in air at 100°C for 5 hours to obtain a modified ultra-high specific surface area mesoporous carbon catalyst B.

[0063] Results The specific surface area of ​​the modified ultra-high specific surface area mesoporous carbon catalyst B is 2570 m 2 / g, pore volume 1.65cm 3 / g, and the average pore size is 10.7nm.

[0064] In addition, the acid density of the modified ultra-high specific surface area mesoporous carbon catalyst B is 3.2 mmol / g.

[0065] The ketal reaction performance of catalyst B was tested according to the method of step (2) in Example 1.

[0066] As a result, the yield of 2,2-dimethyl-1,3-dioxolane was 95.8%.

[0067] Example 3

[0068] (1) Preparation of modified ultra-high specific surface area mesoporous carbon catalyst

[0069] 5 g of ultra-high specific surface area mesoporous carbon (specific surface area of ​​3000 m 2 / g, pore volume 2.0cm 3 / g, average pore size of 14nm) and 5g concentrated sulfuric acid were mixed, transferred to a 100ml autoclave, heated to 150°C, filled with high-purity nitrogen and maintained at a pressure of 5Mpa, and stirred for 20 hours at a stirring rate of 400 rpm. After cooling and depressurizing, the solid product was taken out and washed 5 times with 95°C distilled water. Dry in air at 80°C for 12 hours to obtain a modified ultra-high specific surface area mesoporous carbon catalyst C.

[0070] Results The specific surface area of ​​the modified ultra-high specific surface area mesoporous carbon catalyst C was 2730 m 2 / g, pore volume 1.77cm 3 / g, and the average pore size is 11.6nm.

[0071] In addition, the acid density of the modified ultra-high specific surface area mesoporous carbon catalyst C is 2.5 mmol / g.

[0072] The ketal reaction performance of catalyst C was tested according to the method of step (2) in Example 1.

[0073] As a result, the yield of 2,2-dimethyl-1,3-dioxolane was 95.3%.

[0074] Example 4

[0075] (1) Preparation of modified ultra-high specific surface area mesoporous carbon catalyst

[0076] 5 g of ultra-high specific surface area mesoporous carbon (specific surface area of ​​3000 m 2 / g, pore volume 2.0cm 3 / g, average pore size of 14nm) and 25g concentrated sulfuric acid were mixed, transferred to a 100ml autoclave, heated to 100°C, filled with high-purity nitrogen and maintained at a pressure of 0.5Mpa, and stirred for 8 hours at a stirring rate of 800 rpm. After cooling and depressurizing, the solid product was taken out and washed 10 times with 80°C distilled water. Dry in air at 100°C for 5 hours to obtain a modified ultra-high specific surface area mesoporous carbon catalyst D.

[0077] Results The specific surface area of ​​the modified ultra-high specific surface area mesoporous carbon catalyst D is 2500 m 2 / g, pore volume 1.60cm 3 / g, and the average pore size is 10.0nm.

[0078] In addition, the acid density of the modified ultra-high specific surface area mesoporous carbon catalyst D is 3.5 mmol / g.

[0079] The ketal reaction performance of catalyst D was tested according to the method of step (2) in Example 1.

[0080] As a result, the yield of 2,2-dimethyl-1,3-dioxolane was 94.1%.

[0081] Example 5

[0082] (1) Preparation of modified ultra-high specific surface area mesoporous carbon catalyst

[0083] 5 g of ultra-high specific surface area mesoporous carbon (specific surface area of ​​3000 m 2 / g, pore volume 2.0cm 3 / g, average pore size of 14nm) and 2.5g concentrated sulfuric acid were mixed, transferred to a 100ml autoclave, heated to 150°C, filled with high-purity nitrogen and maintained at a pressure of 5Mpa, and stirred for 20 hours at a stirring rate of 400 rpm. After cooling and depressurizing, the solid product was taken out and washed 5 times with 95°C distilled water. Dry in air at 80°C for 12 hours to obtain a modified ultra-high specific surface area mesoporous carbon catalyst E.

[0084] Results The specific surface area of ​​the modified ultra-high specific surface area mesoporous carbon catalyst E was 2800 m 2 / g, pore volume 1.80cm 3 / g, and the average pore size is 12.0nm.

[0085] In addition, the acid density of the modified ultra-high specific surface area mesoporous carbon catalyst E is 1.8 mmol / g.

[0086] The ketal reaction performance of catalyst E was tested according to the method of step (2) in Example 1.

[0087] As a result, the yield of 2,2-dimethyl-1,3-dioxolane was 93.8%.

[0088] Example 6

[0089] (1) Preparation of modified ultra-high specific surface area mesoporous carbon catalyst

[0090] 5 g of ultra-high specific surface area mesoporous carbon (specific surface area of ​​3000 m 2 / g, pore volume 2.0cm 3 / g, average pore size of 14nm) and 50g concentrated sulfuric acid were mixed, transferred to a 100ml autoclave, heated to 80°C, filled with high-purity nitrogen and maintained at a pressure of 0.2Mpa, and stirred for 4 hours at a stirring rate of 700 rpm. After cooling and unloading the pressure, the solid product was taken out and washed 12 times with 60°C distilled water. Drying in air at 120°C for 3 hours, a modified ultra-high specific surface area mesoporous carbon catalyst F was obtained.

[0091] Results The specific surface area of ​​the modified ultra-high specific surface area mesoporous carbon catalyst F was 2200 m 2 / g, pore volume 1.5cm 3 / g, and the average pore size is 9nm.

[0092] In addition, the acid density of the modified ultra-high specific surface area mesoporous carbon catalyst F is 4.0 mmol / g.

[0093] The ketal reaction performance of catalyst F was tested according to the method of step (2) in Example 1.

[0094] As a result, the yield of 2,2-dimethyl-1,3-dioxolane was 92.2%.

[0095] Example 7

[0096] (1) Preparation of modified ultra-high specific surface area mesoporous carbon catalyst

[0097] 5 g of ultra-high specific surface area mesoporous carbon (specific surface area of ​​3000 m 2 / g, pore volume 2.0cm 3 / g, average pore size of 14nm) and 1g concentrated sulfuric acid were mixed, transferred to a 100ml autoclave, heated to 180°C, filled with high-purity nitrogen and maintained at a pressure of 10Mpa, and stirred for 30 hours at a stirring rate of 300 rpm. After cooling and depressurizing, the solid product was taken out and washed with 90°C distilled water for 6 times. Dry in air at 80°C for 8 hours to obtain a modified ultra-high specific surface area mesoporous carbon catalyst G.

[0098] Results The specific surface area of ​​the modified ultra-high specific surface area mesoporous carbon catalyst G is 2900 m 2 / g, pore volume 1.9cm 3 / g, and the average pore size is 13.0nm.

[0099] In addition, the acid density of the modified ultra-high specific surface area mesoporous carbon catalyst G is 1.3 mmol / g.

[0100] The ketal reaction performance of catalyst G was tested according to the method of step (2) in Example 1.

[0101] As a result, the yield of 2,2-dimethyl-1,3-dioxolane was 91.4%.

[0102] Comparative Example 1

[0103] (1) Preparation of modified ultra-high specific surface area mesoporous carbon catalyst

[0104] 5 g of ultra-high specific surface area mesoporous carbon (specific surface area of ​​3000 m 2 / g, pore volume 2.0cm 3 / g, average pore size of 14nm) and 85g concentrated sulfuric acid were mixed, transferred to a 100ml autoclave, heated to 80°C, filled with high-purity nitrogen and maintained at a pressure of 0.2Mpa, and stirred for 4 hours at a stirring rate of 900 rpm. After cooling and depressurizing, the solid product was taken out and washed 12 times with 60°C distilled water. Dry in air at 120°C for 3 hours to obtain a modified ultra-high specific surface area mesoporous carbon catalyst D1.

[0105] Results The specific surface area of ​​the modified ultra-high specific surface area mesoporous carbon catalyst D1 was 1900 m 2 / g, pore volume 1.1cm 3 / g, and the average pore size is 7nm.

[0106] In addition, the acid density of the modified ultra-high specific surface area mesoporous carbon catalyst D1 is 4.7 mmol / g.

[0107] The ketal reaction performance of catalyst D1 was tested according to the method of step (2) in Example 1.

[0108] As a result, the yield of 2,2-dimethyl-1,3-dioxolane was 86.1%.

[0109] Comparative Example 2

[0110] (1) Preparation of modified ultra-high specific surface area mesoporous carbon catalyst

[0111] 5 g of ultra-high specific surface area mesoporous carbon (specific surface area of ​​3000 m 2 / g, pore volume 2.0cm 3 / g, average pore size of 14nm) and 0.2g concentrated sulfuric acid were mixed, transferred to a 100ml autoclave, heated to 180°C, filled with high-purity nitrogen and maintained at a pressure of 10Mpa, and stirred for 30 hours at a stirring rate of 100 rpm. After cooling and depressurizing, the solid product was taken out and washed with 90°C distilled water for 6 times. Dry in air at 80°C for 8 hours to obtain a modified ultra-high specific surface area mesoporous carbon catalyst D2.

[0112] Results The specific surface area of ​​the modified ultra-high specific surface area mesoporous carbon catalyst D2 was 2940 m 2 / g, pore volume 1.95cm 3 / g, and the average pore size is 13.6nm.

[0113] In addition, the acid density of the modified ultra-high specific surface area mesoporous carbon catalyst D2 is 0.7 mmol / g.

[0114] The ketal reaction performance of catalyst D2 was tested according to the method of step (2) in Example 1.

[0115] As a result, the yield of 2,2-dimethyl-1,3-dioxolane was 81.4%.

[0116] Comparative Example 3

[0117] (1) Preparation of modified ultra-high specific surface area mesoporous carbon catalyst

[0118] 5 g of ultra-high specific surface area mesoporous carbon (specific surface area of ​​3000 m 2 / g, pore volume 2.0cm 3 / g, average pore size of 14nm) and 5g concentrated sulfuric acid were mixed, transferred to a 100ml reactor, heated to 150°C, and stirred for 20 hours at a stirring rate of 600 rpm under normal pressure. After cooling, the solid product was taken out and washed 5 times with 95°C distilled water. It was dried in air at 80°C for 12 hours to obtain a modified ultra-high specific surface area mesoporous carbon catalyst D3.

[0119] Results The specific surface area of ​​the modified ultra-high specific surface area mesoporous carbon catalyst D3 was 2920 m 2 / g, pore volume 1.92cm 3 / g, and the average pore size is 13.3nm.

[0120] In addition, the acid density of the modified ultra-high specific surface area mesoporous carbon catalyst D3 is 0.9 mmol / g.

[0121] The ketal reaction performance of catalyst D3 was tested according to the method of step (2) in Example 1.

[0122] As a result, the yield of 2,2-dimethyl-1,3-dioxolane was 83.2%.

[0123] Comparative Example 4

[0124] 5 g of commercially available silicon dioxide (purchased from Qingdao Hailang Silica Gel Desiccant Factory, with a specific surface area of ​​329 m 2 / g, average particle diameter 1.5mm) and 12g concentrated sulfuric acid were mixed, transferred to a 100ml autoclave, heated to 120°C, filled with high-purity nitrogen and maintained at a pressure of 3Mpa, and stirred for 15 hours at a stirring rate of 500 rpm. After cooling and pressure relief, the solid product was taken out and washed 8 times with 95°C distilled water. It was dried in air at 90°C for 10 hours to obtain condensation catalyst D4.

[0125] Results The specific surface area of ​​the modified condensation catalyst D4 was 205 m 2 / g, pore volume 0.4cm 3 / g, and the average pore size is 16nm.

[0126] In addition, the acid density of the condensation catalyst D4 is 1.2 mmol / g.

[0127] The ketal reaction performance of catalyst D4 was tested according to the method of step (2) in Example 1.

[0128] As a result, the yield of 2,2-dimethyl-1,3-dioxolane was 78.4%.

[0129] Comparative Example 5

[0130] According to the method of step (2) in Example 1, the ketal reaction performance test was carried out using unmodified ultra-high specific surface area mesoporous carbon as catalyst D5.

[0131] As a result, the yield of 2,2-dimethyl-1,3-dioxolane was 2.4%.

[0132] Comparative Example 6

[0133] A modified ultra-high specific surface area mesoporous carbon catalyst was prepared according to the same method as step (1) in Example 1, except that "12 g of concentrated sulfuric acid" was replaced by "12 g of concentrated hydrochloric acid" to obtain a modified ultra-high specific surface area mesoporous carbon catalyst D6.

[0134] Results The specific surface area of ​​the modified ultra-high specific surface area mesoporous carbon catalyst D6 was 2960 m 2 / g, pore volume 1.97cm 3 / g, and the average pore size is 13.8nm.

[0135] In addition, the acid density of the modified ultra-high specific surface area mesoporous carbon catalyst D6 is 0.6 mmol / g.

[0136] The catalytic performance of the modified ultra-high specific surface area mesoporous carbon catalyst D6 was tested using the same catalyst reaction performance evaluation method as in step (2) of Example 1.

[0137] As a result, the yield of 2,2-dimethyl-1,3-dioxolane was 67.5%.

[0138] Comparative Example 7

[0139] The modified ultra-high specific surface area mesoporous carbon catalyst was prepared in the same manner as step (1) in Example 1, except that: 5 g of ultra-high specific surface area mesoporous carbon (specific surface area of ​​3000 m 2 / g, pore volume 2.0cm 3 / g, average pore size of 14nm)" was replaced by "conventional mesoporous carbon material (specific surface area of ​​1500m 2 / g, pore volume 1.2cm 3 / g, and the average pore size is 16nm. )", and the modified ultra-high specific surface area mesoporous carbon catalyst D7 is obtained.

[0140] Results The specific surface area of ​​the modified ultra-high specific surface area mesoporous carbon catalyst D7 was 1040 m 2 / g, pore volume 0.7cm 3 / g, and the average pore size is 13.2nm.

[0141] In addition, the acid density of the modified ultra-high specific surface area mesoporous carbon catalyst D7 is 1.2 mmol / g.

[0142] The catalytic performance of the modified ultra-high specific surface area mesoporous carbon catalyst D7 was tested using the same catalyst reaction performance evaluation method as in step (2) of Example 1.

[0143] As a result, the yield of 2,2-dimethyl-1,3-dioxolane was 84.6%.

[0144] It can be seen from the above results that the modified ultra-high specific surface area mesoporous carbon catalyst provided by the present invention can catalyze the condensation reaction of acetone and ethylene glycol to produce 2,2-dimethyl-1,3-dioxolane, and obtain a higher yield of 2,2-dimethyl-1,3-dioxolane.

[0145] In Comparative Example 1, the surface acid density of the modified ultrahigh specific surface area mesoporous carbon catalyst is too high. When the acid density is too high, some acid centers are not evenly distributed, which will promote the formation of by-products and result in a low yield of 2,2-dimethyl-1,3-dioxolane.

[0146] In Comparative Example 2, the surface acid density of the modified ultra-high specific surface area mesoporous carbon catalyst is too low. When the acid density is too low, the active components are insufficient during the reaction and the catalyst efficiency is reduced, resulting in a lower yield of 2,2-dimethyl-1,3-dioxolane within the same reaction time.

[0147] In Comparative Example 3, when preparing the modified ultra-high specific surface area mesoporous carbon catalyst, no pressure was applied during the acidification process, and the sulfuric acid solid loading was greatly reduced, which reduced the acid density on the catalyst surface, thereby resulting in a lower yield of 2,2-dimethyl-1,3-dioxolane.

[0148] In Comparative Example 4, commercially available silica was used to replace the ultra-high specific surface area mesoporous carbon material to prepare the condensation catalyst. Since the commercially available silica carrier has a relatively small specific surface area and pore volume, it is not conducive to the dispersion of active components and the immobilization of sulfuric acid molecules, which reduces the acid density on the catalyst surface, thereby resulting in a low yield of 2,2-dimethyl-1,3-dioxolane.

[0149] In Comparative Example 5, unmodified ultra-high specific surface area mesoporous carbon was used as a condensation catalyst. Since the surface acidity of the mesoporous carbon material was extremely weak, it could not catalyze the ketal reaction, resulting in an extremely low yield of 2,2-dimethyl-1,3-dioxolane.

[0150] In Comparative Example 6, concentrated hydrochloric acid was used instead of concentrated sulfuric acid as the modification agent. Due to the poor acidification effect of hydrochloric acid, the number of active centers on the catalyst surface was small, and the acid density was low, resulting in a low yield of 2,2-dimethyl-1,3-dioxolane.

[0151] In Comparative Example 7, the ultra-high specific surface area mesoporous carbon material was replaced with a conventional mesoporous carbon material, and the performance of the catalyst was significantly reduced. This is because the specific surface area and pore volume of the conventional mesoporous carbon material are significantly smaller than those of the ultra-high specific surface area mesoporous carbon material, which is not conducive to the immobilization of the active component, resulting in a low yield of 2,2-dimethyl-1,3-dioxolane.

[0152] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A modified ultra-high specific surface area mesoporous carbon catalyst, characterized in that: The modified ultra-high specific surface area mesoporous carbon catalyst is obtained by acidifying the ultra-high specific surface area mesoporous carbon, and the surface acid density of the modified ultra-high specific surface area mesoporous carbon catalyst is 1.3-4 mmol / g.

2. The modified ultra-high specific surface area mesoporous carbon catalyst according to claim 1, wherein: The surface acid density of the modified ultra-high specific surface area mesoporous carbon catalyst is 1.8-3.5 mmol / g; Preferably, the surface acid density of the modified ultra-high specific surface area mesoporous carbon catalyst is 2.5-3.2 mmol / g.

3. The modified ultra-high specific surface area mesoporous carbon catalyst according to claim 1 or 2, wherein: The specific surface area of ​​the ultra-high specific surface area mesoporous carbon material carrier is 2500-3500m 2 / g, pore volume is 1-2.5cm 3 / g, average pore size is 10-14nm; Preferably, the specific surface area of ​​the ultra-high specific surface area mesoporous carbon material carrier is 2800-3000m 2 / g, pore volume is 2-2.5cm 3 / g, and the average pore size is 13-14nm.

4. The modified ultra-high specific surface area mesoporous carbon catalyst according to any one of claims 1 to 3, wherein: The specific surface area of ​​the modified ultra-high specific surface area mesoporous carbon catalyst is 2200-2900m 2 / g, pore volume is 1.5-1.9cm 3 / g, and the average pore size is 9-13nm.

5. A method for preparing a modified ultra-high specific surface area mesoporous carbon catalyst, characterized in that: The preparation method comprises: (1) contacting the ultra-high specific surface area mesoporous carbon with concentrated sulfuric acid under pressure to react to obtain a solid product; (2) washing and drying the solid product to obtain a modified ultra-high specific surface area mesoporous carbon catalyst; Wherein, the weight ratio of the ultra-high specific surface area mesoporous carbon to the concentrated sulfuric acid is 1:(0.2-10).

6. The preparation method according to claim 5, wherein: The weight ratio of the ultra-high specific surface area mesoporous carbon to the concentrated sulfuric acid is 1:(0.5-5).

7. The preparation method according to claim 5, wherein: The contact conditions include: temperature of 80-180°C and time of 4-30 hours; And / or, the pressurization conditions include: a pressure of 0.2-10Mpa, preferably 0.5-5Mpa; And / or, the specific surface area of ​​the ultra-high specific surface area mesoporous carbon material carrier is 2500-3500m 2 / g, pore volume is 1-2.5cm 3 / g, average pore size is 10-14nm; Preferably, the specific surface area of ​​the ultra-high specific surface area mesoporous carbon material carrier is 2800-3000m 2 / g, pore volume is 2-2.5cm 3 / g, and the average pore size is 13-14nm.

8. A modified ultra-high specific surface area mesoporous carbon catalyst prepared by the preparation method described in any one of claims 5 to 7.

9. Use of the modified ultra-high specific surface area mesoporous carbon catalyst according to any one of claims 1 to 4 and 8 in a ketone-alcohol condensation reaction.

10. A method for preparing 2,2-dimethyl-1,3-dioxolane, characterized in that: The method comprises: in the presence of a water-carrying agent, contacting a modified ultra-high specific surface area mesoporous carbon catalyst, acetone and ethylene glycol to carry out a condensation reaction to prepare 2,2-dimethyl-1,3-dioxolane; Wherein, the modified ultra-high specific surface area mesoporous carbon catalyst is the modified ultra-high specific surface area mesoporous carbon catalyst according to any one of claims 1-4 and 8.

11. The use according to claim 10, wherein: The weight ratio of the modified ultra-high specific surface area mesoporous carbon catalyst, the water-carrying agent, acetone and ethylene glycol is 1: (8-50): (10-60): (20-100); And / or, the conditions of the condensation reaction include: temperature of 60-100° C. and time of 0.5-10 h.