【作者】 陆剑平；

【导师】 单国荣；

【作者基本信息】 浙江大学 ， 化学工程（专业学位）， 2011， 硕士

【摘要】 牛磺酸为一简单含硫氨基酸,是人类和哺乳动物的条件必须氨基酸。牛磺酸不参与蛋白质合成,但在细胞、组织、器官、系统水平上起保护调节作用,具有多种生理功能和药理功能,能用于保健和多种疾病的预防与治疗,广泛应用于医药原料、食品、饲料添加剂、化妆品配料等领域,也用于有机合成中间体合成洗涤剂、荧光增白剂等。近年来国际国内市场对牛磺酸的需求旺盛,每年达到5万吨,销售量每年增长20%。为了进一步提高牛磺酸的收率、降低牛磺酸的生产成本,采用乙醇胺和浓硫酸经过酯化生成乙醇胺硫酸酯进而合成牛磺酸,对牛磺酸的合成工艺作了优化,探索了牛磺酸结晶干燥工艺改进。本文对合成反应酯化段和磺化段进行了优化：中和成盐加料温度控制在20-30℃左右,滴加时间不能低于4小时,酯化温度控制在115℃；以亚硫酸钠为磺化剂进行磺化,乙醇胺硫酸酯与亚硫酸钠用量比为1：1.4为宜,磺化反应时间为16小时即基本完成；反应前用碳酸氢铵调节乙醇胺硫酸酯pH值的效果优于使用碳酸钠；比较亚硫酸钠、亚硫酸钾、亚硫酸铵和亚硫酸氢铵四种磺化剂,发现使用亚硫酸铵可得到最高的牛磺酸收率,但后处理不如亚硫酸钠容易。对牛磺酸结晶过程影响因素的研究表明,采用增加溶液过饱和度的方法能使牛磺酸结晶粒径变小且粒径分布趋于均匀；利用乙醇水溶液可改进牛磺酸精结晶效果,通过调节乙醇水溶液浓度、溶液pH值、搅拌速度、降温速度可对牛磺酸的堆积密度、颗粒大小进行有效控制。最佳精结晶条件pH值为5.5,搅拌速度为100转/分钟,10%乙醇溶液为结晶试剂,降温速率2℃/分钟。本文还提出了有效提高牛磺酸的抗结块性能的措施：控制结晶过程,使产品粒径分布均匀；降低产品杂质与水分含量；缩短存放时间；保持仓储温湿度稳定,在阴凉干燥条件储存；适量使用抗结块添加剂(如0.5%二氧化硅)；比较了静态热风干燥、真空双锥回转干燥、微波干燥等干燥方式对牛磺酸晶形粒径分布的影响,表明采用微波干燥或真空微波干燥方式较为适合,能尽可能保持牛磺酸的晶形和粒径分布不变；牛磺酸的稳定性研究确认牛磺酸在纸箱内置PE包装袋包装的情况下,在25℃±2℃下可以贮存3年。更多还原

【Abstract】 Taurine, which is a conditionally essential amino acid containing sulfur element, is one of the most abundant free amino acid in many tissues. Taurine is different than most other amino acids because it is not incorporated into proteins, but it does play many important roles in the body, including bile acid conjugation, detoxification, membrane stabilization, osmoregulation, modulation of excitatory neurotransmission and intracellular calcium levels, then protections for kind cells, tissues, organs and systems. Taurine is widely used as pharmaceutical ingredients, food additives, feed additives, cosmetic ingredients, and synthesis of surfactant, fluorescent bleacher and other organic substance. It is largely demanded in the international and domestic market with a total volume reaching to 50,000 metric tons, and the sales amount increases by more than 20% every year. The main source of taurine is from chemical synthesis.The synthesis method of taurine from monoethanolamine, the process optimization and the improvement for crystallizing and drying of the product were studied, in order to raise the synthesis yield of taurine and reduce the production cost.The optimization of esterification and sulfonation is as below:The temperature dropping sulfuric acid into monoethanolamine between 20-30℃ within time of 4 hours, esterification temperature should be controlled around 115℃; with sodium sulfite as sulfonation agent, the stoichiometric ratio of monoethanolamine hydrosulfate (MES) and sodium sulfite is optimized at 1:1.4, reaction time of 16 hours is enough for sulfonation reaction completion; and it is better to adjust the pH value of the solution of MES with ammonium bicarbonate than sodium carbonate. Among the 4 sulfonation agents, sodium sulfite, ammonium sulfite, potassium sulfite and ammonium hydrogen sulfite, ammonium sulfate can bring the highest yield of tauirne, yet effect of which in the post-processing for desalting is not as efficient as the situations of using sodium sulfite.The research of the influence factors for crystallization process of taurine indicates that the increase of the solution saturation results in smaller particle size of taurine crystallization and even size distribution. Using ethanol solution and regulating the proportion of ethanol and water can improve taurine particle fineness. And the bulk density and particle size of taurine can be adjusted through controlling the pH value, stirring speed, organic solvent polarity, cooling speed. The optimizations for taurine crystallizing are pH 5.5, stirring speed 100 r/min,10% ethanol as solvent, cooling rate 2℃/min.This paper also points out that the methods to improve the anti-caking performance of taurine product:Control the crystallization process to achieve the oven particle size distribution, lower product impurities and moisture content; shorten the storage time; keep storage temperature and humidity stable in a cool and dry storage conditions; use certain anti caking agent (such as silica 0.5%). Several drying methods, such as static hot air drying, double taper turning vacuum drying, and microwave drying, are studied and it shows that the microwave drying or vacuum microwave drying is the suitable drying way, because it keeps as much as possible taurine morphology and size distribution of taurine. The research of the stability of taurine confirm that the validity of taurine packed in PE bag lined carton or polybag and stored under 25±2℃ is above three years.更多还原