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4-yl phenyl carbonate, di(biphenyl-4-yl)carbonate, 4-(1- naphthyl)phenyl phenyl carbonate, 4-(2-naphthyl)phenyl phenyl carbonate, di[ 4-(1-naphthyl)phenyl]carbonate, di-[ 4- (2-naphthyl)phenyl]carbonate, 4-phenoxyphenyl phenyl car› bonate, di( 4-phenoxypheny I )carbonate, 3-pentadecy lpheny I phenyl carbonate, di(3-pentadecylphenyl)carbonate, 4-tri› tylphenyl phenyl carbonate, di( 4-tritylphenyl)carbonate, methyl salicyl phenyl carbonate, di(methylsalicyl)carbonate, ethylsalicyl phenyl carbonate, di( ethylsalicyl)carbonate, n-propylsalicyl phenyl carbonate, di(n-propylsalicyl)carbon› ate, isopropylsalicyl phenyl carbonate, di(isopropylsalicyl) carbonate, n-butylsalicyl phenyl carbonate, di(n-butylsalicyl) carbonate, isobutylsalicyl phenyl carbonate, di(isobutylsali› cyl)carbonate, tert-butylsalicyl phenyl carbonate, di(tert-bu› tylsalicyl) carbonate, di(phenylsaticyl)carbonate and di(benzy lsalicy I )carbonate. 

[0075] Particularly preferred diary! compounds are diphe› nyl carbonate, 4-tert-butylphenyl phenyl carbonate, di( 4-tert› butylphenyl)carbonate, biphenyl-4-yl phenyl carbonate, di(biphenyl-4-yl)carbonate, 4-(1-methyl-1-phenylethyl)phe› nyl phenyl carbonate, di[4-(1-methyl-1-phenylethyl)phenyl] carbonate and di(methylsalicyl)carbonate. 

[0076] Diphenyl carbonate is very particularly preferred. 

[0077] It is possible to use both one diary! carbonate and different diary! carbonates. 

[0078] The diary! carbonates may also be used with residual contents of the monohydroxyaryl compounds from which they were prepared. The residual contents of the mono› hydroxyaryl compounds may be up to 20% by weight, pref› erably up to 10% by weight, particularly preferably up to 5% by weight and very particularly preferably up to 2% by weight. 

[0079] Based on the dihydroxyaryl compound(s), in gen› eral 1.02 to 1.30 mo! of the diary! carbonate(s), preferably 1.04 to 1.25 mo!, particularly preferably 1.045 to 1.22 mo!, very particularly preferably 1.05 to 1.20 mo!, per mole of dihydroxyaryl compound are used. It is also possible to use mixtures of the abovementioned diary! carbonates, the molar amounts per mole of dihydroxyaryl compound which are mentioned above then being based on the total amount of the mixture of the diary! carbonates. 

[0080] For controlling or changing the terminal groups, one or more monohydroxyaryl compound(s) which were not used for the preparation of the diary! carbonate(s) used can addi› tionally be employed. These may be those monohydroxyaryl compounds of the general formula (III) 

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in which 

[0081] RA represents linear or branched C$_{1 }$-C$_{34}$-alkyl, C$_{7}$-C$_{34}$-alkylaryl, CcC$_{34}$-aryl or --COO-RD, RD repre› senting hydrogen, linear or branched C$_{1 }$-C$_{34}$-alkyl, C$_{7}$ -C$_{34}$-alkylaryl or CcC$_{34}$-aryl, and 

[0082] RB, R c independently of one another, are identical or different and represent hydrogen, linear or branched C$_{1 }$-C$_{34}$-alkyl, C$_{7}$-C$_{34}$-alkylaryl or CcC$_{34}$-aryl. 

[0083] Such monohydroxyaryl compounds are, for example, 1-, 2- or 3-methylphenol, 2,4-dimethylphenol 4-ethylphenol, 4-n-propylphenol, 4-isopropylphenol, 4-n› butylphenol, 4-isobutylphenol, 4-tert-butylphenol, 4-n-pen› tylphenol, 4-n-hexylphenol, 4-isooctylphenol, 4-n-nonylphe› nol, 3-pentadecylphenol, 4-cyclohexylphenol, 4-(1-methyl› l-phenylethyl)phenol, 4-phenylphenol, 4-phenoxyphenol, 4-(1-naphthyl)phenol, 4-(2-naphthyl)phenol, 4-tritylphenol, methyl salicylate, ethyl saticylate, n-propyl saticylate, isopro› pyl salicylate, n-butyl salicylate, isobutyl salicylate, tert-butyl salicylate, phenyl salicylate and benzyl salicylate. 

[0084] 4-tert-Butylphenol, 4-isooctylphenol and 3-penta› decylphenol are preferred. 

[0085] The monohydroxyaryl compound(s) should be cho› sen so that the melting point thereof is above that of the monohydroxyaryl compound which was used for the prepa› ration of the diary! carbonate used. The monohydroxyaryl compound may be added at any time in the course of the reaction. It is preferably added at the beginning of the reac› tion. The proportion of free monohydroxyaryl compound may be 0.2 to 20 mo!%, preferably 0.4 to 10 mo!%, based on the dihydroxyaryl compound. 

[0086] It is also possible to change the terminal groups of the resulting polycarbonates by addition of at least one addi› tional diary! carbonate, the base monohydroxyaryl com› pound of which has a higher boiling point than the base monohydroxyaryl compound of the diary! carbonate mainly used. Here too, the additional diary! carbonate may be added at any time in the course of the reaction. It is preferably added at the beginning of the reaction. The proportion of the diary! carbonate having the higher-boiling base monohydroxyaryl compound, based on the total amount of diary! carbonate used, may be 1 to 40 mo! %, preferably 1 to 20 mo! % and particularly preferably 1 to 10 mo! %. 

[0087] Catalysts which may be used in the melt transesteri› fication method for the preparation of polycarbonates are the basic catalysts known in the literature, such as, for example, alkali metal and alkaline earth metal hydroxides and oxides and/or onium salts, such as, for example, ammonium or phos› phonium salts. Preferably onium salts, particularly preferably phosphonium salts, are used in the synthesis. Such phospho› nium salts are, for example those of the general formula (IV) 

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(III) 

in which 

[0088] R 7 - $^{10 }$represent identical or different optionally sub› stituted C$_{1 }$-C$_{10}$-alkyl-, CcC$_{14}$-aryl-, C$_{7}$ -C$_{15}$-arylalkyl or C$_{5}$ -C$_{6}$-cycloalkyl radicals, preferably methyl or C$_{6}$-C$_{14}$- aryl, particularly preferably methyl or phenyl, and 

[0089] x- represents an anion selected from the group con› sisting of hydroxide, sulphate, hydrogen sulphate, bicar› bonate, carbonate, halide, preferably chloride, and alkylate or arylate of the formula-OR 11, in which R$^{11 }$represents an optionally substitutedCcC$_{14}$-aryl-, C$_{7}$-C$_{15}$-arylalkyl or C$_{5}$ -Cccycloalkylrest, C$_{1 }$-C$_{20}$-alkyl, preferably phenyl. 

(IV) 

