Studies On Synthesis Of Taurine From Ethanolamine

Synthesis technics of taurine from ethanolamine has been considered to be an important process for further use of the technology because of the characteristics of raw materials to be wieldy and low operating costs as well as simple technology. Unfortunately, there are still some challenges to overcome the problems of which sulphonating time is too long and the yield of separated products is lower. To solve these problems, esterificating reaction, sulphonating reaction and separating process were studied respectively in this paper. As a result, the conditions of esterificating reaction and separation process were optimized, the tracing method of esterificating reaction was improved,the solubility data of taurine in water and aqueous solution of organic alcohol were measured, and a suitable solvent for separation and purification of taurine was selected.Firstly, the tracing method of esterificating reaction in synthesis process of taurine was studied.We confirmed that both the methods of national standard and the method of acid-base titration using double indicators have some drawbacks for tracing esterificating reaction,and back-titrated with sodium thiosulfate to determine the amount of taurine can be successfully used to trace reaction in this system.Based on the original process for synthesis of taurine, the conditions of esterificating reaction and separation process was optimized.The result show the best condition of esterificating reaction is as follows:toluene as carrying agent, mole ratio between ethanolamine and sulfuric acid is 0.95,volume ratio between carrying agent and ethanolamine is 1.75.Comparing with other reference data, the higher conversion can be obtained using less amount of sulfuric acid and carrying agent under the optimized conditions.Ultrasound was developed to prepare taurine in this paper. By means of Uniform Design method, conversion of 56% was obtained for ethanolamine at the following conditions:T is 75℃, mole ratio of Na2SO3 and NH2CH2CH2OSO3H is 1.8, reaction time is 12 h,ultrasonic power is 200 W.Using laser monitoring technique, the solubility data of taurine in water and aqueous solution of methanol,ethanol and 2-propanol were measured over the temperature range from 274.05 K to 353.05 K.From the experimental data, the solubility data of taurine in the mixture of water+methanol, water+ethanol and water+2-propanol was found to be increased with increasing temperature and decreased with increasing concentration of methanol,ethanol and 2-propanol in aqueous solution.And water+ethanol solution was a kind of better solvent for the purification of taurine.Apelblat equation,the simplified model of ideal solution andλh equation were used to correlate these solubility data, the results showed that the three models agreed well with the experimental data, and Apelblat equation was the best accurate than the other two models for these systems.At last, the solubility data of sodium sulphate in different volume fraction of water+ethanol solution were measured.Comparing the solubility data of sodium sulphate and the solubility data of taurine, the result shown that 10% volume fraction of ethanol in aqueous solution is the good solvent for separation and purification of taurine.