Verfahren zur Herstellung von polymerisierten Kohlensaeureesterderivaten

New polycarbonates are made by condensing a carbonic acid derivative with a 1:3-cyclobutanediol having the formula where R1, R2, R3 and R4 are hydrogen atoms or hydrocarbon radicals, e.g. methyl, ethyl, n-propyl, phenyl or benzyl radicals. The diol may be in the form of its cis-isomer, its transisomer or a mixture thereof. The reaction mixture may also include another dihydroxy compound, e.g. a polyethylene glycol. Catalysts for the reaction are carbonates, hydroxides and cyanides of metals of Group I and II; oxides of metals of Group Ib, II and III; and alkali metal derivatives of carboxylic acids and alcohols. The proportion of cis-units in the polycarbonate may be increased by heating it to 260 DEG -300 DEG C. with evolution of carbon dioxide. The polymers are soluble in chloroform and are suitable for the manufacture of cast, pressed, extruded or injection-moulded articles. In examples, 2,2,4,4-tetramethyl cyclobutane was converted into its di(ethyl carbonate) ester by heating it with ethyl carbonide or ethyl chloroformate (see Group IV(b)). This ester was then heated with 2,2,4,4-tetramethyl cyclobutane-1,3-diol in the presence of lithium hydride to produce the polycarbonate.ALSO:Intermediates for use in the production of polycarbonate (see Group IV(a)) are bis-(carbonic acid esters) of cyclobutane diols of formula: where R1, R2, R3 and R4 are hydrogen atom or hydrocarbon radicals, e.g. methyl, ethyl, n-propyl, phenyl or benzyl radicals. The diols may be in the form of their cis-isomers, their trans-isomers or mixtures thereof. The esters may be made by reacting the diols with alkyl or aryl esters of carbonic acid or with chloroformates. Catalysts for the reaction are carbonates, hydroxides and cyanides of metals of Group I and II; oxides of metals of Group Ib, II and III; and alkali metal derivatives of carboxylic acid and alcohols. In examples, 2,2,4,4-tetramethyl cyclobutane-1,3-diol was converted to its di(ethyl carbonate) ester by heating it with (1) ethyl carbonate in the presence of lithium hydride or (2) ethyl chloroformate in the presence of pyridine.