| 摘要 |
In the manufacture of polycarbonates of dihydric alcohols by polycondensing at an elevated temperature a compound of formula <FORM:1121499/C3/1> in which R is -H or -COOR11, R1 is an aliphatic, araliphatic or cycloaliphatic radical having at least three adjacent carbon atoms between the two oxygen atoms, R11 is a C1C4 alkyl radical or a phenyl radical and x is 1-100, there is used as a catalyst (a) an alkali metal or ammonium salt of a C6- 21 fatty acid, an alkylsuphoni acid or an alkyl substituted arylsulphonic acid (both of the sulphonic acids having 6-21 carbon atoms in their alkyl radicals) or (b) a condensation product of one of said carboxylic or sulphonic acids with an alkanolamine. The intermediate to be polycondensed may be made (i) by reacting a dihydric alcohol with a chloroformate of a monohydric alcohol or a mixture thereof with phosgene or (ii) by reacting a dihydric alcohol with a dialkyl or diaryl carbonate in the presence of a strongly alkaline catalyst containing an alkali metal or ammonium cation. In the latter case the polycondensation catalyst may be formed in situ by adding a free fatty acid to the intermediate. Specified dihydric alcohols are 1:4butanediol, 1:6 - hexanediol, 2:6 - octanediol, 1:12 - dodecanediol, 1:3 - or 1:4 - cyclohexanediol, 1:3- or 1:4-cyclohexanedimethanol, 3- or 4-hydroxymethylcyclohexanol, o-, mor p-bis-(2-hydroxyethyl)-benzene, hydroquinone - bis - (2 - hydroxyethyl) ether, 2:2 - bis(p - 2 - hydroxyethoxyphenyl) - propane and 2:2 - (4:41 - dihydroxydicyclohexyl) - propane. In the examples an intermediate is obtained by passing phosgene into a mixture of 1:4-cyclohexanedimethanol and ethyl alcohol and after removal of the hydrogen chloride and excess ethyl alcohol the product is polycondensed in the presence of various catalysts. |
