Method for determining chloroformate concentration
    6.
    发明授权
    Method for determining chloroformate concentration 失效
    测定氯甲酸盐浓度的方法

    公开(公告)号:US5100804A

    公开(公告)日:1992-03-31

    申请号:US669161

    申请日:1991-03-14

    IPC分类号: C08G64/26 G01N31/16

    摘要: The molar concentration of chloroformate in an organic chloroformate solution is determined by adding an excess of a monohydroxyaromatic compound, water and a catalytic amount of a 4-dialkylaminopyridine such as 4-dimethylaminopyridine, titrating with aqueous base and taking as the end point the volume of base which achieves complete conversation of chloroformate groups to monoaromatic carbonate groups, as shown by a rapid rise in the pH of the aqueous phase of more than two points to a value in the range of 7-9. This method is particularly applicable to the determination of bischloroformate molar concentration in systems to be converted to cyclic polycarbonate oligomers. Conversion may be effected by condensation in the presence of a trialkylamine and aqueous base in the amount of about 3 moles per mole of bischloroformate.

    摘要翻译: 氯甲酸酯在有机氯甲酸酯溶液中的摩尔浓度通过加入过量的单羟基芳族化合物,水和催化量的4-二烷基氨基吡啶如4-二甲基氨基吡啶来测定,用碱水溶液滴定,并以作为终点的体积 碱性化合物可使氯甲酸酯基团完全与单芳族碳酸酯基团进行通讯,如水相pH值的快速上升超过两点所示,为7-9。 该方法特别适用于待转化为环状聚碳酸酯低聚物的体系中双氯甲酸酯摩尔浓度的测定。 转化率可以通过在三烷基胺和碱水溶液的存在下以每摩尔二氯甲酸酯约3摩尔的量进行缩合来进行。

    Method for making flame retardant polycarbonate
    7.
    发明授权
    Method for making flame retardant polycarbonate 失效
    制造阻燃聚碳酸酯的方法

    公开(公告)号:US5300624A

    公开(公告)日:1994-04-05

    申请号:US66381

    申请日:1993-05-24

    CPC分类号: C08G64/24 C08G64/10

    摘要: A method is provided for making flame retardant polycarbonates by phosgenating a mixture of bisphenols having up to about 50 mole % of tetrahalobisphenols, such as tetrabromobisphenols. There is employed a mixture of a phase transfer catalyst and a tertiary organic amine to provide high molecular weight copolymer without excessive phosgene usage.

    摘要翻译: 提供了一种制备阻燃聚碳酸酯的方法,该方法是通过使具有最多约50摩尔%的四卤代双酚(例如四溴双酚)的双酚的混合物进行光气化。 使用相转移催化剂和叔有机胺的混合物以提供高分子量共聚物而不过度使用光气。

    Method for preparing polycarbonates containing aliphatic ester groups
    10.
    发明授权
    Method for preparing polycarbonates containing aliphatic ester groups 失效
    制备含脂肪族酯基团的聚碳酸酯的方法

    公开(公告)号:US5015720A

    公开(公告)日:1991-05-14

    申请号:US535258

    申请日:1990-06-08

    IPC分类号: C08G63/64 C08G64/22

    CPC分类号: C08G63/64

    摘要: Polycarbonates containing aliphatic dicarboxylic ester groups, and having glass transition temperatures and processing temperatures lower than the corresponding homopolycarbonates are prepared via an intermediate which is in turn prepared from a dihydroxyaromatic compound and a C.sub.4-6 aliphatic dicarboxylic acid anhydride, preferably succinic anhydride. Phosgenation of said intermediate produces the desired soft segment polycarbonate.