Abstract: A process for the production of 2,2-bis(4-hydroxyphenyl)propane (BPA) is disclosed. The process that entails reacting acetone with phenol in the presence of cross-linked sulfonated polystyrene resins is characterised in that BPA is separated from the reaction solution downstream of the reaction unit by means of a multi-stage vacuum distillation and a subsequent single- or multi-stage layer crystallisation. The by-product stream with accumulated by-products is returned downstream of the reaction unit.

Abstract: Monodisperse cation-exchangers and anon-exchangers are conditioned by a process and thereafter used as catalysts and for the production of bisphenols.

Abstract: The present invention relates to a process for the manufacture of bis(4-hydroxyaryl)alkanes by heterogeneous acid-catalyzed reaction of aromatic hydroxy compounds with ketones in reactors connected in series, which in the direction of advancing conversion are operated with rising temperature and optionally with increasing loading.

Abstract: The present invention relates to a process for producing bis(4-hydroxy-aryl)alkanes of high purity from addition products of bis(4-hydroxy-aryl)alkanes and aromatic hydroxy compounds which are obtained by the acid-catalysed reaction of the aromatic hydroxy compounds with ketones.

Abstract: The present invention relates to a process for the continuous production of dihydroxydiarylalkanes (bisphenols) by the reaction of fresh phenol, phenol and isoalkenylphenol from the decomposition of by-products, and ketone. In this process the bulk of the bisphenol is recovered from the reaction mixture by crystallization and the mother liquor obtained is freed from phenol by distillation. The phenol is returned to the reaction and the bottoms obtained during the distillation are decomposed in a reactive rectification after addition of a basic catalyst. The phenol and isoalkenylphenol leaving at the top are led back into the reaction; the bottoms from the first reactive column are acidified and in a second reactive rectification, in the presence of an acid catalyst, are further decomposed into phenol, which distils off and is reused in the reaction, and bottoms, which are disposed of.

Abstract: The present invention relates to a process for the production of bis(4-hydroxyaryl)alkanes by an acid-catalyzed reaction between aromatic hydroxy compounds and ketones, in which the temperature, ketone content and water content of a liquid reaction mixture are adjusted by means of a suitably composed gas phase.

Abstract: A process is disclosed for the preparation and purification of 3-(4-hydroxyphenyl)-1,1,3-trimethylindan-5-ol. Accordingly, isopropenylphenol, its dimers or oligomers undergo isomerization in the presence of an acid catalyst, crude 3-(4-hydroxyphenyl)-1,1,3-trimethylindan-5-ol is isolated from the reaction mixture and purified by distillation.

Abstract: The present invention relates to a process for the production of bis-(4-hydroxyaryl)-alkanes by a heterogeneously catalyzed reaction of aromatic hydroxy compounds with ketones in at least two reactors connected in series, which, as the reaction progresses, are operated at higher temperatures, wherein the total quantity of ketone is divided between the individual reactors in such a manner that the higher is the temperature of the particular reactor, the smaller is the proportion per reactor, the highest possible reactor loading is maintained and the temperatures and temperature gradients are kept as low as possible.

Abstract: The present invention relates to a process for working up the residual mother liquors from the production of dihydroxydiarylalkanes (bisphenols) discharged from the process once the bisphenol has been separated.

Abstract: The invention relates to the synthesis of bisphenols from monophenols and carbonyl compounds such as aldehydes and ketones using concentrated mineral acids such as hydrochloric acid and/or hydrogen chloride gas as acid catalysts and a mercaptan as cocatalyst, which is fixed by an ion pair bond to a matrix that is insoluble in the reaction medium.

Abstract: The invention relates to a process for the synthesis of bis-(4-hydroxyphenyl)-alkanes on ion-exchange resins or mixtures of ion-exchange resins which are modified with alkyl-SH groups, wherein the monophenols and carbonyl compounds to be used have first been purified to remove substances which can transfer alkyl groups.

Abstract: The object of the present invention is polycarbonate molding compositions containing polycarbonates, stabilizers of the general formula (I)R.sub.1 --X--CZ--Y--R.sub.2and optionally polypropylene glycols. The object of the present invention is also use of these molding compositions to produce items for medical applications.

Abstract: The invention relates to the synthesis of bisphenols from monophenols and carbonyl compounds such as aldehydes and ketones with concentrated mineral acids such as hydrochloric acid and/or hydrogen chloride gas as acid catalysts and a mercaptan as cocatalyst, which is fixed by an ion-pair bond to a matrix insoluble in the reaction medium.

Abstract: The present invention relates to polycarbonate molding compositions containing polycarbonates, stabilizers of general formula ##STR1## and optionally polypropylene glycols. The present invention also relates to the use of these molding compositions for the production of articles for medical applications.

Abstract: The present invention provides polycarbonates stabilized against .gamma.-radiation and their use for the production of medical equipment.

Abstract: A thermoplastic molding composition stabilized against .gamma.-rays and its application for manufacture of medical equipment is disclosed. The composition contains an aromatic polycarbonate and(i) dialkyl and/or dicycloalkyl monosulfides or polysulfides in an amount of 0.001 to 5 weight %, and optionally(ii) aliphatic or cycloaliphatic monoalcohols or polyalcohols or their derivatives in an amount of 0.001 to 2 weight %said percent being relative to 100 weight % of aromatic polycarbonate.

Abstract: A process for purifying aromatic carbonate polymers, including polycarbonates and polyestercarbonates, is disclosed. Accordingly a carbonate polymer in an organic solvent is rendered virtually free of low molecular weight components by agitation with aluminosilicate or by passing through layers of such aluminosilicate. The aluminosilicate is subsequently separated off and the carbonate polymer is isolated in known methods.

Abstract: A method of preparing aliphatic-aromatic polycarbonate resin is disclosed. Accordingly, the method entails reacting an oligocarbonate of diphenol having chlorocarbonic acid ester terminal groups, with an aliphatic diol, in a non-aqueous solvent. The amount of solvent is such that the oligocarbonate is about 10-40% relative to the total weight of solvent, oligocarbonate and diol.

Abstract: A process for producing an aliphatic-aromatic polycarbonate is disclosed. The process comprise (A) reacting in an anhydrous neutral solvent (i) an oligocarbonate of diphenol with (ii) an aliphatic dicarboxylic acid, and (B) eliminating the hydrogen chloride and carbon dioxide by-products. The oligocarbonate of diphenol is characterized in that it is terminated by chlorocarbonic acid ester groups. The resins thus prepared are readily molded conventionally.

Abstract: A process for purifying aromatic carbonate polymers, including polycarbonates and polyestercarbonates, is disclosed. Accordingly, a carbonate polymer is an organic solvent is rendered virtually free of low molecular weight components by agitation with aluminosilicate or by passing through layers of such aluminosilicate. The aluminosilicate is subsequently separated off and the carbonate polymer is isolated in known methods.