Method for preparing benzoin product in mother liquor recycling manner

A cyclic preparation and benzoin technology, which is applied in the preparation of carbon-based compounds, chemical instruments and methods, preparation of organic compounds, etc., can solve the problems of methanol toxicity and flammability, high production cost, low reaction yield, etc., and is convenient for industrial production. , The effect of low production cost and high product yield

Active Publication Date: 2014-07-23
煌途医药(无锡)有限公司
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Problems solved by technology

[0006] "Journal of Hubei University for Nationalities (Natural Science Edition)" Vol. 26 No. 2, "Packaging Engineering" Vol. 25 No. 6, "Journal of North China Coal Medical College" Vol. 25 No. 6, "Chemical Bulletin" 2002 No. Phase 1 discloses that benzaldehyde is used as a raw material, methanol or ethanol solution is used as a reaction solvent, and vitamin B1 is used as a catalyst to carry out bimolecular condensation reaction under alkaline conditions to prepare benzoin products. The disadvantages are that the reaction yield is low and the production cost higher
[0007] Volume 6, No. 5 of "Fine Chemical Intermediates" discloses the preparation of benzoin products through benzaldehyde condensation reaction using thiazole salts as catalysts. For example, benzaldehyde and thiazole salts are added in proportion to the reaction kettle. , carry out bimolecular condensation reaction, after the reaction is finished, cool and precipitate crystals, filter with suction, wash with ice absolute ethanol, and vacuum-dry to obtain the benzoin product of white needle-like crystals. The disadvantage is that the reaction yield is low and the production cost is relatively high
[0008] Using methanol solution as a reaction solvent, sodium cyanide as a catalyst, and benzaldehyde performing a bimolecular condensation reaction to generate benzoin is a technology commonly used in industrial production processes, and it is also the only feasible industrial production technology compared to the above-mentioned disclosed technologies; The further improved technology is to use 50-60% low-concentration methanol solution, add quaternary ammonium salt cationic surfactant to improve the mass transfer effect of the phase interface, improve the conversion rate of raw materials and the yield of products, the technical method exists The main problem is that after the condensation reaction is over, the product obtained is not a crystalline substance with a relatively large particle size, but a form of fine crystals mixed in the reaction solvent to form a reaction mixture. After cooling, a part of the microcrystalline product aggregates and forms Granular agglomerated product, which contains a lot of impurities; another part of the microcrystalline product is directly mixed in the reaction solvent to form a slurry-like solid-liquid mixture, and the reaction products in the two states are blended to form the final reaction mixture. Carry out solid-liquid separation to extract the required solids as benzoin products; because the slurry-like solid-liquid mixture causes great difficulties in the separation of products, the separation efficiency is very low in the case of forced separation. In addition, the separated solids are filtered The cake contains more impurities and the mother liquor of the encapsulation reaction, forming a stronger wet filter cake, which will form a harder solid block after drying and removing the solvent, which needs to be crushed by a pulverizer to form a light yellow fine powder benzoin product
[0011] As we all know, methanol has the disadvantages of toxicity, flammability, explosion, and volatility.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027]Obtain 290g of the reaction mother liquor from the process of "the source of the reaction mother liquor", add it to a reaction flask with a mechanical stirrer, a thermometer, and a reflux condenser, and then add 200g of benzaldehyde, 40g of water, 1.13g of hydrocyanic acid, and 4.2g of polyethylene Diol, 1.8g dodecyldimethylbenzyl ammonium chloride, 0.78g cyclohexane, 0.6g sodium sulfate, stir, heat up to 50-53°C, add 1.0g dodecyldimethylbenzyl Ammonium chloride, heat preservation reaction for 1.5h, add 1.0g dodecyl dimethyl benzyl ammonium chloride; heat up to 60-65°C, heat preservation reaction for 2.5h, the reaction is completed, cool down to 20-30°C, to obtain solid and liquid The reaction mixture is filtered, and the separated filtrate is both the reaction mother liquor and weighs 302g; the solid crude product of benzoin is separated, washed with 70-80 (wt.)% ethanol to remove surface impurities, and dried to obtain a white granular crystalline product. The melting ...

Embodiment 2

[0029] Obtain reaction mother liquor 302g from embodiment 1, add in reaction flask with mechanical stirring, thermometer, reflux condenser, then add successively 200g benzaldehyde, 30g water, 1.2g hydrocyanic acid, 4.0g polyethylene glycol, 3.0 g dodecyldimethylbenzyl ammonium chloride, 0.6g cyclohexane, 0.36g sodium carbonate, stir, heat up to 55-58°C, add 1.0g dodecyldimethylbenzyl ammonium chloride, Heat preservation reaction for 2.0 hours, add 1.0g of dodecyl dimethyl benzyl ammonium chloride; heat up to 62-65°C, heat preservation reaction for 2.5h after the reaction is completed, cool down to 20-30°C to obtain a solid-liquid reaction mixture, filter , the separated filtrate reacted with the mother liquor and weighed 295g; the solid crude product of benzoin was separated, washed with 70-80 (wt.)% ethanol to remove surface impurities, and dried to obtain a white granular crystalline product with a melting point of 133.6-135.0 °C, yield 87.0%.

Embodiment 3

[0031] Obtain reaction mother liquor 295g from embodiment 2, add in reaction flask with mechanical stirring, thermometer, reflux condenser, then add successively 200g benzaldehyde, 50g water, 1.2g hydrocyanic acid, 4.8g polyethylene glycol, 0.9 g dodecyldimethylbenzyl ammonium chloride, 0.84g isooctane, 0.96g sodium carbonate, stir, heat up to 55-58°C, add 1.0g dodecyldimethylbenzyl ammonium chloride, Heat preservation reaction for 1.5h, add 1.0g of dodecyl dimethyl benzyl ammonium chloride; heat up to 60-63°C, heat preservation reaction for 2.0h after the reaction is completed, cool down to 20-30°C to obtain a solid-liquid reaction mixture, filter , the separated filtrate reacted with the mother liquor and weighed 280g; the solid crude product of benzoin was separated, washed with 70-80 (wt.)% ethanol to remove surface impurities, and dried to obtain a white granular crystalline product with a melting point of 133.2-135.7 °C, yield 86.5%.

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Abstract

The invention relates to a method for preparing a benzoin product in a mother liquor recycling manner, and belongs to the technical field of preparation processes of chemical products. The method comprises the following steps: sequentially and proportionally adding reaction mother liquor, benzaldehyde, water, hydrocyanic acid, a cationic surface active agent, a phase transfer catalyst, a dispersing agent and an inorganic salt which are obtained in a reaction process in the preparation of the benzoin product into a reaction kettle; stirring and heating to 45 DEG C to 65 DEG C; adding the cationic surface active agent and reacting for 1.0 to 2.0 hours in a heat preservation manner; adding the cationic surface active agent, heating to 55 DEG C to 70 DEG C and reacting for 1.5 to 2.5 hours in the heat preservation manner until the finishing of the reaction; separating a crude benzoin solid product, washing with an ethanol solution and drying so as to obtain a white crystalline product, wherein separated filtrate is the reaction mother liquor; and collecting and weighing the reaction mother liquor so as to serve as a reaction solvent for recycling. The method has the characteristics of being simple in production process, high in benzoin product yield, good in benzoin product quality, low in production cost and convenient for industrial production.

Description

technical field [0001] The invention relates to a technical method for preparing benzoin products by circulating mother liquor, and belongs to the technical field of chemical product preparation technology. The chemical structural formula of benzoin product is: [0002] Background technique [0003] Benzoin is an important organic synthesis product, which is widely used as a photosensitizer for photosensitive resins and an anti-cratering agent for powder coatings; in addition, benzoin is also widely used as an intermediate for synthetic dyes and synthetic medicines. [0004] The synthetic method of benzoin is that benzaldehyde is used as a raw material, methanol or ethanol solution is used as a reaction solvent, sodium cyanide is used as a catalyst, and benzaldehyde is generated by bimolecular condensation reaction. [0005] [0006] "Journal of Hubei University for Nationalities (Natural Science Edition)" Vol. 26 No. 2, "Packaging Engineering" Vol. 25 No. 6, "Journal...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C49/83C07C45/75
CPCC07C45/73C07C49/83
Inventor 杜飞马发林李家杰孙亚雷
Owner 煌途医药(无锡)有限公司
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