摘要:
This invention relates to branched thermoplastic polycarbonates containing hydroxybenzotriazoles corresponding to the following general formula (I): ##STR1##
摘要:
The invention relates to a process for coating moldings via co-extrusion with a UV-absorber-containing layer containing special dimeric UV absorbers and to the moldings coated with a corresponding layer.
摘要:
A thermoplastic molding composition is disclosed comprising a polydiorganosiloxane-polycarbonate block cocondensate and 0.5% to 15% by weight of a particular hydroxy benzotriazole. The composition is characterized by its improved protection against UV light.
摘要:
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.
摘要:
A process for the preparation of carbonates containing aromatic ester groups is disclosed. The process entails reacting aromatic monohydroxy componds with phosgene or with chlorocarbonic acid esters of aromatic monohydroxy compounds at a temperature of 50 to 350° C. and in the presence of active carbon as catalyst.
摘要:
Aromatic amines are produced by catalytic hydrogenation of corresponding aromatic nitro compounds in the gas phase, by carrying out the hydrogenation in the presence of catalysts which, besides palladium, vanadium and lead, contain in addition molybdenum, tungsten and/or rhenium on a ceramic support having a BET surface area of less than 40 m.sup.3 /g, at temperatures of from 180.degree. C. to 500.degree. C. in a catalyst bed and in a molar ratio of hydrogen to the nitro group or nitro groups of 3:1 to 30:1.
摘要:
4-aminodiphenylamines are produced by hydrogenating nitrobenzene with hydrogen in the presence of bases containing hydroxide and/or oxide groups and heterogeneous catalysts and in the presence of inert aprotic solvents at temperatures of 0 to 200.degree. C. and pressures of 0.1 to 150 bars.
摘要:
Catalyst systems with a content of a platinum-group-metal catalyst, a co-catalyst, a quaternary salt and a base for the oxidative carbonylation of aromatic hydroxy compounds to the corresponding diaryl carbonates are obtained according to the invention as a residual melt by melt crystallization and can be returned into the carbonylation reaction or worked up to valuable materials. The melt crystallizate, which consists predominantly of diaryl carbonate and the parent aromatic hydroxy compound, is worked up to pure diaryl carbonate and pure hydroxy compound.
摘要:
Aromatic amines are produced by hydrogenation of the associated aromatic nitro compounds in the gas phase over fixed catalysts. The catalysts contain active hydrogenation metals on supports. The reaction is conducted at a pressure of 2-50 bar and at a temperature in the range 250.degree.-500.degree. C. under adiabatic conditions. A circulating gas is passed over the catalyst, which circulating gas contains 3-150 moles of hydrogen, 2-100 moles of the amino groups to be formed per mole of nitro groups, and 2 to 6 moles of water per amino group equivalent. The amine and water formed, as well as a purification stream, are separated from the circulating gas. Thereafter the circulating gas is enriched with volatilised aromatic nitro compound and fresh hydrogen and recycled.