CN104324749B - A kind of alkaline ionic liquid catalyst of based on POSS of carbonate synthesis glyceride and preparation method thereof - Google Patents

Abstract

The invention discloses a basic ionic liquid catalyst based on POSS (Polyhedral Oligomeric Silsesquioxanes, polyhedral oligomeric silsesquioxanes) for synthesizing glycerol carbonate and a preparation method thereof. The catalyst carrier is octachloropropylsilsesquioxane POSS‑Cl, and the modification component is alkaline ionic liquid. The preparation method of the catalyst is as follows: first synthesizing POSS-Cl, and then carrying out immobilization of the basic ionic liquid, modifying the POSS, and obtaining the basic ionic liquid catalyst based on the POSS. The invention has the advantages that the prepared catalyst is used to catalyze the synthesis of glycerol carbonate system, has high catalytic efficiency, is solvent-free, can be recycled, and the production process is environmentally friendly.

Description

A kind of basic ionic liquid catalyst based on POSS for synthesizing glycerol carbonate and preparation method thereof

technical field

The invention relates to the preparation and application of a POSS-based alkaline ionic liquid catalyst for synthesizing glycerol carbonate, and belongs to the technical field of glycerin application.

Background technique

The world is paying more and more attention to the shortage of petroleum resources and environmental protection, and the development of biodiesel synthesis has become a hot spot in the development of new energy sources in the world. In the process of biodiesel production, a large amount of glycerol will be produced by-product, and its effective utilization restricts the economical efficiency of biodiesel production. Therefore, the research and application of chemicals using glycerol as raw materials has attracted widespread attention from all over the world.

As a green and renewable chemical, glycerol carbonate can be widely used in polyurethane foam, coatings, detergents, and cosmetics industries. At the same time, as an important intermediate of organic chemical industry, glycerol carbonate has the advantages of low flammability, low toxicity, high boiling point, biodegradability, etc., and has a good industrial application prospect.

As a new type of environmentally friendly solvent and liquid catalyst, alkaline ionic liquid has been widely used in the field of catalysis in recent years. It has high-density reactive sites and non-volatility of solid catalysts. Its structure and active sites are adjustable. It is a truly designable green catalyst. However, most ionic liquids are difficult to separate from the product after the reaction, which restricts the industrialization process of its catalyzed preparation of glycerol carbonate.

Using a new type of POSS as a carrier and a basic ionic liquid as a modification component, the prepared POSS-based basic ionic liquid catalyst not only has the high activity of a homogeneous catalyst, but also avoids the diffusion limitation in the heterogeneous catalysis process, and at the same time It endows the catalyst with the characteristics of easy separation, simplifies the operation process, and reduces the operation cost, which has attracted widespread attention at present.

In order to solve the above problems, the present invention provides a POSS-based alkaline ionic liquid catalyst for synthesizing glycerol carbonate and a preparation method thereof, which meet the requirements of green chemistry and have attractive industrialization prospects.

Contents of the invention

The object of the present invention is to provide a kind of basic ionic liquid catalyst based on POSS of synthesizing glycerol carbonate and preparation method thereof. The catalyst prepared by the method has the characteristics of high activity and easy separation.

The present invention is realized by following technical scheme, a kind of alkaline ionic liquid catalyst based on POSS of synthesizing glycerol carbonate, described is glycerol and dimethyl carbonate synthesizing glycerol carbonate, synthesizing glycerol carbonate based on POSS The preparation method of alkaline ionic liquid catalyst is characterized in that comprising following process,

(1) Preparation of POSS-Cl: Take 100-200ml of methanol, 5-15ml of concentrated hydrochloric acid into a three-necked flask, and add 10-20g of 3-chloropropyltriethoxysilane dropwise into the above solution, mechanically After stirring for 30 to 50 hours, add 0.1 to 0.2 g of dibutylstannane as a condensation catalyst to the above mixture, react in an oil bath at 40 to 60°C for 30 to 50 hours and cool down to room temperature to obtain a white crystal precipitate of octachloropropyl silsesquisil Oxane POSS-Cl;

(2) Immobilization of basic ionic liquid: Dissolve 0.1-0.3g POSS-Cl in 20-30ml dimethylformamide in a three-necked round-bottomed flask, and slowly add 0.08-0.1mol of N-alkylimidazole dropwise , heated up to 60-75°C under magnetic stirring, continued to stir and reflux for 18-32 hours after the dropwise addition, filtered under reduced pressure, washed 2-5 times with ethyl acetate to obtain a white solid, and finally dried in vacuum at 60-90°C for 18-32 hours , to obtain the precursor, take 0.8-2g KOH and put it into a 50ml single-necked round bottom flask, and add 10-20ml dimethylformamide, stir at room temperature to dissolve, add 0.1-0.3g of the above-mentioned precursor in batches, Stir and react at room temperature for 2 to 5 hours, then add 4 to 8 ml of ether into the bottle, continue to react at room temperature for 18 to 32 hours, stop the reaction, remove the solvent by rotary evaporation, and obtain an imidazole basic ionic liquid based on POSS as a solid catalyst.

The aforementioned N-alkylimidazole is any one of N-methylimidazole, N-ethylimidazole, N-isopropylimidazole, N-allylimidazole or N-vinylimidazole.

The above-mentioned making based on POSS alkaline ionic liquid catalyst is used for the technique of synthetic glycerol carbonate, it is characterized in that comprising following process:

(1) Glycerol and dimethyl carbonate are added in the reactor according to the molar ratio of 1: 5～1: 15, and then adding quality is the alkaline ionic liquid catalyst based on POSS of 1～10% of the total mass of reactant, in reaction The temperature is 50-200°C, the pressure is 1-3Mpa, the stirring rate is 500-1200rpm, and the reaction time is 1-10h to obtain a mixture containing glycerol carbonate;

(2) Filter the mixture in step (1), and continue to recycle the filtered solid catalyst.

The advantage of the invention is that the catalyst has the characteristics of high activity and easy separation, and is expected to become a very competitive cleaning process route.

The present invention will be further described below through specific examples, but the present invention will not be limited.

detailed description

【Example 1】

Preparation of POSS-Cl: Add 150ml of methanol and 10ml of concentrated hydrochloric acid into a three-necked flask, and add 15g of 3-chloropropyltriethoxysilane dropwise into the above solution, after mechanical stirring for 32h, add 0.12g of condensation catalyst Dibutylstannane was added to the above mixture, reacted in an oil bath at 50°C for 36 hours and cooled to room temperature to obtain a white crystal precipitate of octachloropropylsilsesquioxane POSS-Cl;

Immobilization of basic ionic liquid: Dissolve 0.15g of POSS-Cl in 25ml of dimethylformamide in a three-neck round bottom flask, slowly add 0.08mol of N-methylimidazole dropwise, and raise the temperature to 60°C under magnetic stirring. After the dropwise addition, continue to stir and reflux for 24 h, filter under reduced pressure, wash with ethyl acetate three times to obtain a white solid, and finally vacuum dry at 65° C. for 24 h to obtain a precursor. Take 1g of KOH and add it to a 50ml single-necked round bottom flask, and add 15ml of dimethylformamide, stir at room temperature to dissolve, add 0.2g of precursor in batches, react at room temperature for 3h under magnetic stirring, and then add 6ml of diethyl ether, continue to react at room temperature for 24h, stop the reaction, and remove the solvent by rotary evaporation to obtain a POSS-based imidazole basic ionic liquid as a solid catalyst.

[Example 2]

Under the situation that the preparation conditions of the catalyst are exactly the same as in Example 1, only the N-methylimidazole in the preparation method is changed into N-ethylimidazole to obtain the imidazole basic ionic liquid catalyst based on POSS.

[Example 3]

Under the situation that the preparation conditions of the catalyst are exactly the same as in Example 1, only the N-methylimidazole in the preparation method is changed to N-isopropylimidazole to obtain the imidazole basic ionic liquid catalyst based on POSS.

【Example 4】

Under the situation that the preparation conditions of the catalyst are exactly the same as in Example 1, only the N-methylimidazole in the preparation method is changed to N-allylimidazole to obtain the imidazole basic ionic liquid catalyst based on POSS.

【Reaction Example 5-8】

In a 1L reactor, add reactant 9.2g glycerol and 60.8g dimethyl carbonate, add 3.5g POSS-based imidazole basic ionic liquid catalyst, at a reaction temperature of 100°C, a pressure of 2Mpa, and a stirring rate of 800rpm , The reaction time is 6h. Taking glycerol carbonate selectivity and yield as indicators, the obtained reaction properties are shown in Table 1.

Table 1 The reaction result of synthesizing glycerol carbonate based on the imidazole alkaline ionic liquid catalyst of POSS

[Reaction Example 9]

Recycling performance of POSS-based imidazole basic ionic liquid catalysts.

In a 1L reactor, add reactant 9.2g glycerol and 60.8g dimethyl carbonate, add 3.5g POSS-based imidazole basic ionic liquid catalyst, at a reaction temperature of 100°C, a pressure of 2Mpa, and a stirring rate of 800rpm , The reaction time is 6h. After the reaction, the catalyst was filtered, dried at 90° C. for 4 h, and the catalyst was recycled. Taking the selectivity and yield of glycerol carbonate as indicators, the obtained reaction performance is shown in Table 2.

Table 2 Recycling performance of POSS-based imidazole alkaline ionic liquid catalysts

Claims (3)

1. a preparation method based on the POSS alkaline ionic liquid catalyst of synthesizing glycerol carbonate, it is characterized in that comprising following process, (1) Preparation of POSS-Cl: Take 100-200ml of methanol, 5-15ml of concentrated hydrochloric acid into a three-necked flask, and add 10-20g of 3-chloropropyltriethoxysilane dropwise into the above solution, mechanically After stirring for 30 to 50 hours, add 0.1 to 0.2 g of dibutylstannane as a condensation catalyst to the above mixture, react in an oil bath at 40 to 60°C for 30 to 50 hours and cool down to room temperature to obtain a white crystal precipitate of octachloropropyl silsesquisil Oxane POSS-Cl; (2) Immobilization of basic ionic liquid: Dissolve 0.1-0.3g POSS-Cl in 20-30ml dimethylformamide in a three-necked round-bottomed flask, and slowly add 0.08-0.1mol of N-alkylimidazole dropwise , heated up to 60-75°C under magnetic stirring, continued to stir and reflux for 18-32 hours after the dropwise addition, filtered under reduced pressure, washed 2-5 times with ethyl acetate to obtain a white solid, and finally dried in vacuum at 60-90°C for 18-32 hours , to obtain the precursor, take 0.8-2g KOH and put it into a 50ml single-necked round bottom flask, and add 10-20ml dimethylformamide, stir at room temperature to dissolve, add 0.1-0.3g of the above-mentioned precursor in batches, Stir and react at room temperature for 2 to 5 hours, then add 4 to 8 ml of ether into the bottle, continue to react at room temperature for 18 to 32 hours, stop the reaction, remove the solvent by rotary evaporation, and obtain an imidazole basic ionic liquid based on POSS as a solid catalyst. 2. by the preparation method of the basic ionic liquid catalyst based on POSS of the synthetic glycerol carbonate claimed in claim 1, it is characterized in that, above-mentioned N-alkylimidazole is N-methylimidazole, N-ethylimidazole or N - any of isopropyl imidazoles. 3. the catalyzer that the preparation method of catalyzer obtains by claim 1 is used for the technique of catalyzed synthetic glycerol carbonate, it is characterized in that comprising following process: (1) Glycerol and dimethyl carbonate are added in the reactor according to the molar ratio of 1: 5～1: 15, and then adding quality is the alkaline ionic liquid catalyst based on POSS of 1～10% of the total mass of reactant, in reaction The temperature is 50-200°C, the pressure is 1-3MPa, the stirring rate is 500-1200rpm, and the reaction time is 1-10h to obtain a mixture containing glycerol carbonate; (2) Filter the mixture in step (1), and continue to recycle the filtered solid catalyst.