Studies On The Preparation And Pilot Plant Test Of Taurine Via Water-quenching Esterification Of Monoethylamine

Taurine (2-aminoethylsulfonic acid), which is the most abundant intracellular amino acid in human and mammalian, is a conditionally semi-essential amino acid containing sulphur. It is not incorporated into proteins but found either free or in some simple peptides, or combining with glycine and bilic acid into taurocholic acid. Because of the role in numerous physiological processes such as membrane stabilization, detoxification, antioxidation, osmoregulation, maintenance of calcium homeostasis, glycolysis and glycogenesis stimulation, and etc., it is implicated in numerous biological and physiological functions and thus used widely as pharmaceutical, food, feed, cosmetic ingredients and etc. It is also a raw material for organic synthesis. The demand for Taurine has been increasing dramatically by 20% annually, with a figure of 40 thousand tons in year 2010.Taurine is prepared mainly by chemical synthesis methods, mainstream ones among which are the methods from monoethanolamine and ethylene oxide as raw materials. This study prepares taurine via reactions of esterification and sulfonation, adopting monoethanolamine, sulfuric acid and sodium sulfite as raw materials. It mainly studies the water-quenching in esterification of monethanolamine, the optimization of sulfonation conditions, and the pilot plant test for production of taurine. It is the first time preparing with water-quenching method the aminoethyl hydrogen sulfate, in which process cold water is put into the esterificating material when it turns into paste and is difficult to be stirred, to let the aminoethyl hydrogen sulfate crystalize and then be separated by centrifugation from the mother liquid. High purity ester is obtained and sulphonated by sodium sulfite into taurine. The optimization of esterification reaction conditions are: stoichiometric ratio of monethanolamine and sulfuric acid 1:1.025, monoethanolamine diluted to 75%, temperature for salt-forming below 40℃, temperature for esterification dehydration 105～115℃, water consumption for quenching 3.5 to 4m times(m is a certain coefficient) stoichiometrically to monoethanolamine. The esterification yield is up to 99% with purity of 99%(on dry basis),3% and 1.5% higher than those of the old process (say frying to dry method). The optimization of sulphonated reaction condition is:sodium sulfite excesses by 20% to aminoethyl hydrogen sulfate, temperature for sulphonation 102～105℃, reaction time 24 hours. Totally taurine yield of experience increases by 5% up to 65%. According to the lab test results, this study also researches the pilot plant scale test, founds the production process and control points, chooses the production equipments, designs and installs a pilot workshop, establishes working instruction and the rules for safe operation, pilot operation results comply with and are better than lab tests. The total yield of taurine is increased to 65.2% by a ratio of 6.2%.