Lactic acids solution polycondensation

Takasu et al. [24] reported that scandium trifluoromethanesulfonate [Sc(OTQ3] and scandium trifluoromethanesulfonimide [Sc(NTf2)s] are effective for one-step dehydration polycondensation of L-lactic acid. Bulk polycondensation of L-lactic acid was carried out at 130-170°C to give PLLA with Mn of 5.1 xlO -7.3xl0 (yield 32%-60%). However, the solution polycondensation was... 

No one had believed that direct polycondensation of L-lactic acid can give a high molecular weight of PLLA, until 1995 when Mitsui Chemical Co. first succeeded in synthesizing such a PLLA by using a special solution polycondensation technique. With this epoch-making success, many researchers including the present authors made efforts to establish the direct polycondensation of L-lactic acid. As shown in Scheme 1.22, two equilibria exist in the dehydrative polycondensation of L-lactic acid one is hydration/... 

Following the success of the solution polycondensation, bulk polycondensation of L-lactic acid was studied to eliminate the use of solvent. 

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