اصالح روش خالص‌سازي ديمر حلقوي الكتيد

Improvement in Purification Method of a Synthesized Cyclic Dimeric Lactide

Lactide was synthes ized by rever se polymeri zation of low molecular weig ht poly(lactic acid) with two different molecular weight s:1500 and 2500 . Two differe nt lactid e purification processes such as: recrystalli zation in eth yl acetate and washing the crude lactide with ether before recrys tallizatio n in ethy l acetate were evaluated . It has been demonstrated that increasing the molecul ar weight of pol y(lactic acid) does not influ ence the produ ction yield, melting point and optica l rotation of lactide. The washing of crude lactid e with ether and recrystallization in eth yl ace tate can be carried out in a shor t period of time (within I day) at a high yield (35%) using less solvent. In contrast, the first purification meth od gives lower (11%) production yield by using highe r amount of solvent at longer ,- - - - - - - _ time. It is also found that the purification methods do not have any specific effec t on the pro perties of lactide.