The purpose of the present invention is to provide a preparation method of cocoyl glutamic acid, which has the characteristics of simple operation, safety and high reaction yield in each step of the preparation route, and is easy to industrialize production.
The technical solution adopted to achieve the above purpose, including steps,
1) take coconut oil acid and phosgene as raw material, be 1: 1.05~3.5: 0.05~0.2 by the mol ratio of coconut oil acid, phosgene and catalyzer, under organic amine catalyst effect, coconut oil acid is at 70~120 ℃ Under the micro-melting state, the phosgene reaction was carried out for 5~30 hours, and the reaction was completed, and the cocoyl chloride was obtained by vacuum distillation under reduced pressure;
2) at room temperature, sodium glutamate is dissolved in the mixed solution of alcohol and water, and the mass ratio of alcohol and water is 1:1.0~10.0, after dissolving, the control system temperature is 0~50 ℃, under insulation and stirring, drip simultaneously. Add the aqueous solution of cocoyl chloride and sodium hydroxide, the mol ratio of sodium amino acid and cocoyl chloride is 1: 1.0~1.6, the time for adding is about 0.5~6 hour, and the rate of addition of sodium hydroxide and consumption are maintained at 6 with the system pH value Between ~ 15, dripping is completed, stirring 0.5 ~ 6h; Keep temperature at 0 ~ 100 DEG C, desolventizing under reduced pressure 0.5 ~ 6h; Cooling, temperature control at 0 ~ 50 DEG C, under stirring, slowly add hydrochloric acid dropwise , the amount of hydrochloric acid dripping is maintained between 0~10 with the pH value of the system, and the dripping is completed, and granular crystals are separated out, suction filtration, and after drying, the cocoyl glutamic acid is obtained.
beneficial effect
Compared with the prior art, the present invention has the following advantages;
(1) Cocoyl chloride is produced by the phosgene method, and a large amount of phosphorus-containing waste water will not be produced because phosphorus trichloride is used as a chlorination reagent. It is sold as hydrochloric acid, and carbon dioxide can be used to prepare sodium carbonate to achieve the effect of reuse and cost saving;
(2) the present invention adopts alcohol and water mixed solution to replace acetone and water mixed solution and pure water system in the traditional sense, avoids the generation of side reaction, solves the problem of product yellowing, improves product yield simultaneously, gained product Milder, better smell, color and quality;
(3) the present invention adopts the method of low-temperature desolvation and low-temperature crystallization to replace the method of traditional high-temperature acidification and liquid separation after the condensation stage is finished, which reduces the energy consumption in production, and greatly improves the operation while saving costs. security;
(4) The method for the cocoyl glutamic acid prepared by the present invention is easy to operate, has high reaction yield, is easy to industrialize production, and basically has no three wastes.