2007•Fine Chemical IntermediatesRequires access
Preparation of Polylactic Acid Intermediate Lactide
Deng Xue-lian
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Abstract
Preparation of lactide was carried out using indirect method in this paper. Lactide was synthesized from industrial monomer D,L-lactic acid as raw material. The optimal conditions for synthesis of lactide were investigated by the orthogonal experiments. Results indicated that under the optimal conditions such as using v(Sn(Oct)2)/v(Lactic acid)=0.4∶1 Sn(Oct)2 as catalyst,dehydration temperature 180℃ and decomposing temperature 285℃,the yield of lactide reach 72.4%,and the yield of lactide reached 59.3% after the first recrystalization,and its melting point ranged from 95.0℃ to 96.2℃. The yield of lactide reached to 50.7% and its melting point ranged from 125.2℃ to 126.5℃ after the fifth recrystallization. FTIR and 1H NMR were used to characterizing the products.