Novel allantoin synthesis process

Abstract

The invention discloses a novel technique for synthesizing allantoin, comprising the following steps that: alkali is added into a solvent of methanol or ethanol or water in a stirring state, methyl dichloroacetate or dichloroacetic acid are dropped to react, inorganic acid is added into the mixed solution to react, and a dihydroxy acetate solution is obtained after filtration, the obtained dihydroxy acetate solution is distilled, carbamide and the inorganic acid are added into the mixture, the mixture is stirred at a temperature of between 70 and 90 DEG C and reacts on the condition of heat preservation, and the reaction product is cooled to the room temperature, washed to be neutral and dried so that the product of the allantoin is obtained. The method takes the methyl dichloroacetate or the dichloroacetic acid as a raw material to synthesize the allantoin, lowers the production cost, has quality improvement and has a yield up to about 62 percent; meanwhile, a chloroacetic acid mother liquid is utilized indirectly to reduce the environment pollution caused by emission. The method does not pollute the environment, has simple and convenient operation and low energy consumption, and meets the requirements on energy conservation and emission reduction.

Description

technical field

[0001] The invention relates to a synthetic process of a chemical product, in particular to a new synthetic process of an allantoin product. Background technique

[0002] Allantoin (allantoin), also known as 5-ureidohydantoin, is an important urea deep-processing product, which belongs to imidazole heterocyclic compounds, and its chemical name is: 1-ureidodiazapentane-2, 4-diketone or 2,5-dioxo-4-imidazolidinyl urea, formula C 4 h 6 N 4 o 3 , molecular weight 158.12. Allantoin is an important fine chemical product. This product has physiological functions such as promoting cell growth, accelerating wound healing, and softening cuticle proteins. It is widely used in the production of medicine, cosmetics, agriculture and industrial preservatives.

[0003] At present, the method for preparing allantoin is mainly to synthesize glyoxylic acid and urea, or to obtain glyoxylic acid by catalytic oxidation of glyoxal and then synthesize two methods with urea, but...

Examples

Embodiment 1

[0017] While stirring, add 4.0 mol (160 g) of sodium hydroxide to 15 mol (480 g) of methanol, and after stirring for 1 hour, add 1 mol (143 g) of methyl dichloroacetate dropwise at 70 ° C. After the dropwise addition, keep warm and reflux And continue to stir for 6 hours, add 1mol (118g) of 31% hydrochloric acid, then filter out the solid, wash twice with 1mol (32g) methanol, and combine the washing filtrates to obtain a sodium dihydroxyacetate solution; Distill and recover methanol, stop the distillation when the gas phase temperature rises to 100°C, add 4mol (240g) of urea, 4mol (471g) of 31% hydrochloric acid, stir and keep warm at 90°C under reflux for 6 hours, cool to room temperature, and wash with water until Neutral, dry in an oven at 110°C to obtain 0.626mol (99g) of allantoin finished product, the product yield is 62.6%, and the infrared spectrum is consistent with the standard spectrum.

Embodiment 2

[0019] While stirring, add 8.0 mol (448 g) of potassium hydroxide to 30 mol (960 g) of methanol, stir evenly, add 2 mol (286 g) of methyl dichloroacetate dropwise at 75°C, keep warm and reflux after the dropwise addition and continue Stir for 6 hours, add 2mol (236g) of 31% hydrochloric acid to neutralize, then filter out the solid, wash twice with 2mol (64g) methanol, and combine the washing filtrates to obtain a potassium dihydroxyacetate solution; Distill and recover methanol, stop the distillation when the gas phase temperature rises to 95°C, add 8mol (480g) of urea, 9mol (1060g) of 31% hydrochloric acid, stir and keep warm at 75°C for 4 hours, cool to room temperature, wash with water until Neutral, dry in an oven at 120°C to obtain 1.24mol (196g) of allantoin finished product, the product yield is 62.1%, and the infrared spectrum is consistent with the standard spectrum.

Embodiment 3

[0021] While stirring, add 10 mol (560 g) of potassium hydroxide to 40 mol (3680 g) of ethanol. After stirring for 1.2 hours, add 3 mol (387 g) of dichloroacetic acid dropwise at 70°C. After the dropwise addition, keep warm and reflux and continue stirring 6 hours, add 3mol (155g) 95% sulfuric acid (1 / 2H 2 SO 4 ), then filter out the solid, wash twice with 4mol (184g) ethanol, and combine the washing filtrates to obtain a potassium diglycolate solution; the obtained potassium diglycolate solution is distilled to recover ethanol, and the gas phase temperature rises to 98°C Stop distillation, add 12mol (720g) urea, 10mol (516g) 95% sulfuric acid (1 / 2H 2 SO 4 ), stirred and kept at 85°C for 8 hours, cooled to room temperature, filtered and washed with water until neutral, dried in an oven at 120°C to obtain 1.88mol (297g) of allantoin finished product, product yield 61.6%, infrared spectrum and standard The spectra are consistent.

technical field

[0001] The invention relates to a synthetic process of a chemical product, in particular to a new synthetic process of an allantoin product. Background technique

[0002] Allantoin (allantoin), also known as 5-ureidohydantoin, is an important urea deep-processing product, which belongs to imidazole heterocyclic compounds, and its chemical name is: 1-ureidodiazapentane-2, 4-diketone or 2,5-dioxo-4-imidazolidinyl urea, formula C 4 h 6 N 4 o 3 , molecular weight 158.12. Allantoin is an important fine chemical product. This product has physiological functions such as promoting cell growth, accelerating wound healing, and softening cuticle proteins. It is widely used in the production of medicine, cosmetics, agriculture and industrial preservatives.

[0003] At present, the method for preparing allantoin is mainly to synthesize glyoxylic acid and urea, or to obtain glyoxylic acid by catalytic oxidation of glyoxal and then synthesize two methods with urea, but...

Examples

Embodiment 1

[0017] While stirring, add 4.0 mol (160 g) of sodium hydroxide to 15 mol (480 g) of methanol, and after stirring for 1 hour, add 1 mol (143 g) of methyl dichloroacetate dropwise at 70 ° C. After the dropwise addition, keep warm and reflux And continue to stir for 6 hours, add 1mol (118g) of 31% hydrochloric acid, then filter out the solid, wash twice with 1mol (32g) methanol, and combine the washing filtrates to obtain a sodium dihydroxyacetate solution; Distill and recover methanol, stop the distillation when the gas phase temperature rises to 100°C, add 4mol (240g) of urea, 4mol (471g) of 31% hydrochloric acid, stir and keep warm at 90°C under reflux for 6 hours, cool to room temperature, and wash with water until Neutral, dry in an oven at 110°C to obtain 0.626mol (99g) of allantoin finished product, the product yield is 62.6%, and the infrared spectrum is consistent with the standard spectrum.

Embodiment 2

[0019] While stirring, add 8.0 mol (448 g) of potassium hydroxide to 30 mol (960 g) of methanol, stir evenly, add 2 mol (286 g) of methyl dichloroacetate dropwise at 75°C, keep warm and reflux after the dropwise addition and continue Stir for 6 hours, add 2mol (236g) of 31% hydrochloric acid to neutralize, then filter out the solid, wash twice with 2mol (64g) methanol, and combine the washing filtrates to obtain a potassium dihydroxyacetate solution; Distill and recover methanol, stop the distillation when the gas phase temperature rises to 95°C, add 8mol (480g) of urea, 9mol (1060g) of 31% hydrochloric acid, stir and keep warm at 75°C for 4 hours, cool to room temperature, wash with water until Neutral, dry in an oven at 120°C to obtain 1.24mol (196g) of allantoin finished product, the product yield is 62.1%, and the infrared spectrum is consistent with the standard spectrum.

Embodiment 3

[0021] While stirring, add 10 mol (560 g) of potassium hydroxide to 40 mol (3680 g) of ethanol. After stirring for 1.2 hours, add 3 mol (387 g) of dichloroacetic acid dropwise at 70°C. After the dropwise addition, keep warm and reflux and continue stirring 6 hours, add 3mol (155g) 95% sulfuric acid (1 / 2H 2 SO 4 ), then filter out the solid, wash twice with 4mol (184g) ethanol, and combine the washing filtrates to obtain a potassium diglycolate solution; the obtained potassium diglycolate solution is distilled to recover ethanol, and the gas phase temperature rises to 98°C Stop distillation, add 12mol (720g) urea, 10mol (516g) 95% sulfuric acid (1 / 2H 2 SO 4 ), stirred and kept at 85°C for 8 hours, cooled to room temperature, filtered and washed with water until neutral, dried in an oven at 120°C to obtain 1.88mol (297g) of allantoin finished product, product yield 61.6%, infrared spectrum and standard The spectra are consistent.