- 专利标题: Recovery of lactic acid values from a meso-lactide stream
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申请号: US13203075申请日: 2010-03-12
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公开(公告)号: US08552209B2公开(公告)日: 2013-10-08
- 发明人: Richard Douglas Benson , Joseph D. Schroeder
- 申请人: Richard Douglas Benson , Joseph D. Schroeder
- 申请人地址: US MN Minnetonka
- 专利权人: NatureWorks LLC
- 当前专利权人: NatureWorks LLC
- 当前专利权人地址: US MN Minnetonka
- 代理机构: Gary C Cohn PLLC
- 国际申请: PCT/US2010/027117 WO 20100312
- 国际公布: WO2010/105142 WO 20100916
- 主分类号: C07D319/00
- IPC分类号: C07D319/00
摘要:
Lactic acid equivalents are recovered from a starting lactide stream by catalytically racemizing a portion of the lactide in the stream at a temperature of 180° C. or below. This increases the proportion of two species of lactide (i.e., at least two of S,S-, R,R- or meso-lactide) at the expense of the third species. The racemized mixture so obtained can be separated to recover some or all of one or more of the lactide species from the remaining lactide species, by a process such as melt crystallization or distillation. Impurities in the starting lactide stream usually are retained mostly in the remaining meso-lactide, so a highly purified S,S- and/or R,R-lactide stream can be produced in this manner. Such a purified S,S- and R,R-lactide stream is suitable for polymerization to form a polylactide.
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