发明授权
- 专利标题: Phosphate salts of AB-polybenzoxazole monomer
- 专利标题(中): AB-聚苯并恶唑单体的磷酸盐
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申请号: US546596申请日: 1990-06-29
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公开(公告)号: US5068384A公开(公告)日: 1991-11-26
- 发明人: William J. Harris , Zenon Lysenko , Carl W. Hurtig
- 申请人: William J. Harris , Zenon Lysenko , Carl W. Hurtig
- 申请人地址: MI Midland
- 专利权人: The Dow Chemical Company
- 当前专利权人: The Dow Chemical Company
- 当前专利权人地址: MI Midland
- 主分类号: C07C227/06
- IPC分类号: C07C227/06 ; C08G73/22
摘要:
AB-polybenzoxazole monomer, such as 3-amino-4-hydroxybenzoic acid, can be synthesized in high yields from a hydroxy-benzoic acid or related compound in a three-step process of (1) nitration, (2) hydrolysis of the ester, and (3) reduction of the nitro moiety. The monomer is conveniently recovered as a phosphate salt in high purity by precipitating and recrystallizing from a phosphoric acid solution.
公开/授权文献
- US5601223A Cable transporting and turning device 公开/授权日:1997-02-11