The purpose of the present invention is to provide a method for preparing cocoyl glutamic acid, which has the characteristics of simple and safe operation, high reaction yield and easy industrial production.
The technical solution adopted to achieve the above purpose, including steps,
1) take coconut oil and phosgene as raw material, be 1: 1.05～3.5:0.05～0.2 by the mol ratio of coconut oil, phosgene and catalyzer, under organic amine catalyst effect, coconut oil is at 70～120 ℃ Pass phosgene reaction 5～30 hours under the micro-melt state, and reaction is finished, and vacuum distillation under reduced pressure obtains described cocoyl chloride;
2) at room temperature, dissolve sodium glutamate in the mixed solution of alcohol and water, the mass ratio of alcohol and water is 1:1.0～10.0, after dissolving, control system temperature to be 0～50 ℃, under insulated 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, and the about 0.5～6 hour of dropping time, sodium hydroxide addition rate and consumption maintain on 6 with system pH value Between ~15, drop complete, stir 0.5 ~ 6h; Keep temperature at 0 ~ 100 DEG C, decompression desolventization 0.5 ~ 6h; Cooling, temperature control is at 0 ~ 50 DEG C, under stirring, slowly add hydrochloric acid dropwise , the amount of hydrochloric acid added dropwise maintains between 0～10 with system pH value, drop finishes, and separates out granular crystal, suction filtration, after oven dry, obtain cocoyl glutamic acid.
Compared with the prior art, the present invention has the following advantages;
(1) produce cocoyl chloride by phosgene method, can not produce a large amount of phosphorus-containing wastewaters as chlorination reagent because of phosphorus trichloride, the sulfur dioxide that thionyl chloride method produces is serious to environmental pollution, and the hydrogen chloride produced by phosgene method can be produced It can be sold as hydrochloric acid, and carbon dioxide can be used to prepare sodium carbonate, so as to achieve the effect of repeated utilization and cost saving;
(2) The present invention replaces the mixed solution of acetone and water and the pure water system in the traditional sense by adopting the mixed solution of alcohol and water to avoid the generation of side reactions, solve the problem of product yellowing, and improve the product yield simultaneously, and the obtained product Milder, better smell, color and quality;
(3) After the condensation stage is over, the present invention adopts low-temperature desolventization and low-temperature crystallization to replace the traditional high-temperature acidification liquid separation method, which reduces the energy consumption in production and greatly improves the operation while saving costs. security;
(4) The method for cocoyl glutamic acid prepared by the present invention is easy to operate, has a high reaction yield, is easy to industrialized production, and basically has no three wastes.
A preparation method for cocoyl glutamic acid, comprising steps:
Step 1: in the 500ml there-necked flask that stirring bar, thermometer, air guide pipe, reflux condenser are housed, add coconut oil 284g (1mol) successively, N, N-dimethyl formamide 4.5g (0.06mol), heat up To 80 DEG C, the control reaction temperature is 80～85 DEG C, feeds phosgene 105g (1.05mol), and reaction is completed in 5～8 hours, vacuum distillation under reduced pressure collects 140～180 DEG C (560Pa) cut, obtains Cocoyl chloride 265g, yield 90%.
Step 2: in the 100ml there-necked flask that dropping funnel, thermometer, stirring are housed, add sodium glutamate 191g (1mol), be dissolved in 446g ethanol and water mixed solution (m ethanol:m water=1:4), Stir at room temperature to make it dissolve, cocoyl chloride is put into the dropping funnel of 500ml, and the temperature control of the low-temperature water bath is at 20～25 ℃, adds cocoyl chloride 359g (1.2mol) under stirring, drops 40% simultaneously Aqueous sodium hydroxide solution, keep the pH value of the reaction solution at pH=10~12, after dropping, continue to stir for 2h; Add hydrochloric acid dropwise, make system pH=6～8, separate out granular crystal, after suction filtration, after drying, obtain cocoyl glutamic acid 339g, yield 92%.
