Abstract: Ethyl-3-methyl-thiopropionate (EMTP) is an important kind of spice. The key factors and conditions for bio-catalytic synthesis of EMTP in non-aqueous system were studied in the paper. The results indicated that the best catalyst in solvent-free medium or normal hexane was Novozym 435. Catalyst dosage, the amount of molecular sieve addition, the number of acetic acid addition, reaction temperature and reaction time were important factors for EMTP synthesis. The optimal preparation conditions, as determined using orthogonal array design method, were 50 mg of Novozym 435, 2 g of molecular sieve, 42 ℃ of reaction temperature, 30 h of reaction time, three times of acetic acid addition with an interval of 2 h, and 150 r/min of shaking speed. The yield of EMTP reached up to 42.4% in solvent-free medium under the optimal conditions.

Key words: 3-(methylthio)-propane, ethyl-3-methyl-thiopropionate, Novozym 435, conversion in non-aqueous media, solvent-free system