Method of polycarbonate preparation

    公开(公告)号:US06576739B2

    公开(公告)日:2003-06-10

    申请号:US09735871

    申请日:2000-12-14

    IPC分类号: C08G6400

    CPC分类号: C08G64/24 C07C68/02 C07C69/96

    摘要: High molecular weight polycarbonates are prepared from hindered bisphenols in a reaction sequence involving conversion of the hindered bisphenol to the corresponding bischloroformate and subsequent treatment with an amine catalyst and aqueous base to effect polymerization by hydrolysis and condensation of the bischloroformate groups. Tertiary aliphatic and cycloaliphatic amine catalysts bearing at least one methyl group are found to be especially effective in promoting this polymerization reaction. Reaction rates and selectivities are shown to be superior to known methods employing tertiary amines lacking methyl groups attached to nitrogen, such as triethylamine. The inclusion of chain stoppers allows the preparation of well defined mixtures of polycarbonate oligomers from hindered bisphenols. Additionally, the methodology may be used to prepare symmetrical diaryl carbonates from hindered phenols.

    Interfacial method of preparing ester-substituted diaryl carbonates
    3.
    发明授权
    Interfacial method of preparing ester-substituted diaryl carbonates 有权
    制备酯取代的碳酸二芳基酯的界面方法

    公开(公告)号:US06420588B1

    公开(公告)日:2002-07-16

    申请号:US09911440

    申请日:2001-07-24

    IPC分类号: C07C6996

    CPC分类号: C07C68/02 C07C69/96

    摘要: High yields of ester-substituted diary carbonates such as bis-methyl salicyl carbonate were obtained by the condensation of methyl salicylate with phosgene in the presence of a phase transfer catalyst (PTC) in an interfacial reaction system in which the pH of the aqueous phase was greater than 9.3. Using the method of the present invention conversions of greater than 99% were obtained whereas under standard conditions using triethylamine as the catalyst conversions were limited to 70-75% of the methyl salicylate starting material even with a 20 mole % excess of added phosgene. The optimized conditions of the of the present invention use only a slight excess of phosgene and represent an attractive route for the manufacture of bis methyl salicyl carbonate and ester-substituted diaryl carbonates generally.

    摘要翻译: 通过在界面反应体系中存在相转移催化剂(PTC)的情况下,通过水杨酸甲酯与光气的缩合得到高产率的酯取代的二元碳酸酯,其中水相的pH为 大于9.3。 使用本发明的方法获得大于99%的转化率,而在使用三乙胺的标准条件下,即使使用20摩尔%过量的加入的光气,催化剂转化率也限于水杨酸甲酯起始原料的70-75%。 本发明的优化条件仅使用轻微过量的光气,并且代表通常用于制造碳酸双甲基水杨酸酯和酯取代的二芳基碳酸酯的有吸引力的途径。