It is understood that triethanolamine is a colorless, transparent and viscous liquid at room temperature, with a slight ammonia smell. It is hygroscopic and can absorb moisture and carbon dioxide in the air. Can be freely mixed with water and alcohol, soluble in chloroform, slightly soluble in benzene and ether. The pH of 0.1moI/L solution is 10.5. There is a danger of burning when exposed to high heat, open flame or contact with oxidants. Its aqueous solution is corrosive.
The preparation method of triethanolamine is as follows:
1. Combine ethylene oxide, Ammonia water is fed into the reactor, and the condensation reaction is carried out at a reaction temperature of 30-40°C and a reaction pressure of 70.9-304kPa to generate a mixture of mono-, di- and triethanolamine. After dehydration and concentration at 90-120°C, three Perform vacuum distillation in a vacuum distillation tower and intercept fractions according to different boiling points to obtain monoethanolamine, diethanolamine and triethanolamine finished products with a purity of 99%. During the reaction process, if the proportion of ethylene oxide is increased, the production ratio of di- and triethanolamine will increase, which can increase the yield of di- and triethanolamine.
Refining method: The triethanolamine content of industrial products is more than 80%, and the rest contains less than 1.0% water, less than 2.5% ethanolamine, 15% diethanolamine, and a small amount of polyethylene glycol and other impurities. During refining, ethanolamine is removed by steam distillation, sodium hydroxide is added to precipitate triethanolamine into an alkali metal salt, neutralized after separation, and then distilled under reduced pressure to obtain pure product.
2. Use the industrial product triethanolamine to purify and extract under reduced pressure.
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