摘要:
Novel ruthenium catalysts additionally contain carbonates, hydroxides and/or hydrated oxides of cerium and manganese or of manganese and/or dehydration products thereof. They can optionally be present on a support material and can be prepared by converting soluble compounds of ruthenium, cerium and manganese by treatment with alkaline compounds into insoluble compounds and optionally further treating these. Such catalysts are particularly suitable for the preparation of cycloaliphatic polyamines by hydrogenation of corresponding aromatic amines.
摘要:
Substituted 1,2,3,4-tetrahydrocarbazoles of the formula ##STR1## having the meaning for R.sup.1 to R.sup.8 indicated in the description, can be prepared by catalytically hydrogenating a substituted phenol of the formula ##STR2## reacting the hydrogenation solution with a phenylhydrazine of the formula ##STR3## to give the hydrazone and cyclizing the hydrazone under acidic conditions.
摘要:
Dialkyl carbonates can be prepared by reaction of carbon monoxide with alkyl nitrites in a continuous gas-phase reaction using a platinum metal catalyst on a metal phosphate support and adding hydrogen halide stepwise or continuously during the course of the reaction in almost quantitative selectivity; the corresponding dialkyl oxalates are formed in such small amounts that in most cases they cannot be detected.
摘要:
The present invention relates to a process for preparing menthol isomers by selective rearrangement of stereoisomers of menthol or mixtures thereof in the presence of ruthenium-containing supported catalysts doped with or comprising alkaline earth metal alkoxides, and to the catalysts themselves.
摘要:
Succinic anhydride (SA) can be prepared by catalytic hydrogenation of maleic anhydride (MA) with hydrogen in the liquid phase, by reacting a starting material composed of from 5 to 100% by weight of MA and from 95 to 0% by weight of SA, based on the total weight of MA and SA, at from 120.degree. to 150.degree. C. and a H.sub.2 pressure of from 10 to 150 bar over a Raney skeleton catalyst or a platinum group metal catalyst.
摘要:
The invention relates to mixtures of polyarylene sulfides (PAS), preferably polyphenylene sulfide (PPS), and pyrenes. The mixtures show reduced radical formation under highly accelerated weathering conditions (UV irradiation).
摘要:
Corrosion inhibitor and method of protecting metallic materials in strongly alkaline medium by means of a corrosion inhibitor, characterized in that it contains an amine containing at least one CH group bound to the nitrogen.
摘要:
In the process for preparing an aromatic carbonate from an aromatic hydroxy compound, CO and O2 in the presence of a quaternary salt and a base using a platinum metal catalyst and a cocatalyst, use is advantageously made of supported catalysts containing, in the reaction-ready state, (i) a platinum metal, a platinum metal halide or a platinum metal halide complex and (ii) a metal compound acting as cocatalyst from groups IB, IIB, IIIA, IIIB, IVA, IVB, VB, VIB, VIIB, the iron group (atomic numbers 26-28) or the rare earth metals (atomic numbers 58-71) of the Periodic Table of the Elements (Mendeleev), each in an amount of 0.01-15% by weight, calculated as metal and based on the total weight of the catalyst.
摘要:
Diphenylamine can be dehydrocyclized on noble metal catalysts in the liquid phase at temperatures of 200.degree. to 340.degree. C. The reaction proceeds with a surprisingly high selectivity.
摘要:
Carbonic diesters containing at least one aromatic ester group can be prepared from carbonic diesters containing at least one aliphatic ester group by transesterification using a phenol, titanium dioxide having a surface area of at least 20 m.sup.2 /g as determined by the BET method being used as catalyst.