Abstract:

A process of taurine preparation with ethanolamine is divided into two parts, esterification reaction and sulfonation reaction. (NH₄)₂SO₃ was used as sulfonating agent. Sulfonation conditions in the presence of ammonia gas were optimized to be reaction temperature 105℃, reaction time 12 h, material ratio of (NH₄)₂SO₃ to 2-aminoethyl hydrogen sulfate 1.65, and 4 times of batch feeding. Under these conditions, the conversion rate of 2-aminoethyl hydrogen sulfate was 76.43%. The separation technique for the mixed solution of sulfonated reaction was investigated. Firstly, inorganic salt (NH₄)₂SO₄, which is one of products, was removed by chemical precipitation. After filtering out the sediment sulfate MeSO₄, the liquor was slightly heated, so that another resultant NH₃·H₂O was decomposed into ammonia gas and water. Experimental results show that the desalination rate is over 98% by this method. Secondly, the solvent crystallization method was used for separation of the liquid mixture containing taurine and 2-aminoethyl hydrogen sulfate. The influences of crystallization temperature, crystallization time, cooling rate and stirring rate on crystallization process were examined by uniform design method. The optimum crystallization conditions were found as follows: crystallization temperature 13.9℃, crystallization time 1 h, cooling rate 0.5℃·min^-1 and stirring speed 350—450 r·min^-1. The crystallization yield of taurine was 67.94% and its purity was almost 100%.

Key words: taurine, ammonium sulfite , desalination, crystallization, chemical process

摘要：

乙醇胺酯化-磺化法制备牛磺酸工艺分为酯化反应和磺化反应两部分, 用亚硫酸铵代替亚硫酸钠作为磺化反应的原料, 在含氨气体存在下与2-氨基乙醇硫酸酯进行磺化反应, 得到的优化条件为:反应温度为98℃, 反应时间为12 h, 物料配比(n_亚硫酸铵:n_酯)为1.65, 分4批加料, 2-氨基乙醇硫酸酯的转化率可以达到76.43%。对磺化反应后的混合溶液的分离提纯进行研究。首先用化学沉淀法除去其中的无机盐(NH₄)₂SO₄, 滤出沉淀物硫酸盐后稍微加热母液, 生成的NH₃·H₂O分解放出的氨气用于磺化反应过程, 此过程的除盐率达到98%以上。采用溶剂结晶法对含有牛磺酸、未反应完的2-氨基乙醇硫酸酯和不到2%的滤液物系进行分离。用均匀实验设计法考察了结晶温度、结晶时间、降温速率和搅拌速率对牛磺酸结晶过程的影响, 并用软件对实验结果进行回归分析, 得到溶剂结晶较优的工艺条件为:结晶温度为13.9℃, 结晶时间为1 h, 搅拌速率为低速搅拌(350～450 r·min^-1), 降温速率为0.5℃·min^-1 。在此条件下, 牛磺酸的一次结晶率可达到67.94%, 纯度接近100%。

关键词: 牛磺酸, 亚硫酸铵, 脱盐, 结晶, 化学过程