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.
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:
In the process for preparing an aromatic carbonate from an aromatic hydroxy compound, CO and O.sub.2 in the presence of a quaternary salt and a base, use is advantageously made of supported catalysts which, in the reaction-ready state, contain a platinum metal, a platinum metal compound or a complex containing a platinum metal compound on a support comprising a metal oxide whose metal can occur in a plurality of oxidation states.
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:
Process for hydrogenating aromatic polymers in the presence of catalysts, wherein a metal or mixture of metals from group VIII of the Periodic Table together with a support of silicon dioxide, aluminium dioxide or a mixture thereof is used as the catalyst, and the catalyst pore volume defined by pores of diameters between 100 and 1000 Å, measured by mercury porosimetry, is generally from 100 to 15%, in relation to the total pore volume, measured by mercury porosimetry.
摘要:
New hydrated niobium oxide and hydrated tantalum oxide catalysts containing pores having diameters in the range from 0.4 to 10,000 nm are characterized in that the volume of the pores of the catalyst having a diameter of from 100 to 1000 nm is at least 30% of the total pore volume of the catalyst. The catalysts can be prepared by mixing hydrated niobium oxide or hydrated tantalum oxide with an inert solid and converting this mixture into a solid pellet form, with the pressure in the apparatus for preparing catalysts in pellet form being set in such a way that the volume of the pores of the catalyst having a diameter of from 100 to 1000 nm is at least 30% of the total pore volume of the catalyst. Such catalysts are particularly suitable for preparing N-alkylanilines from anilines and alkanols.
摘要:
Dialkyl carbonates can be prepared by reacting carbon monoxide with alkyl nitrites in a continuous gas phase reaction in the presence of a heterogeneous platinum metal catalyst, the activity of this catalyst being maintained by the addition of small amounts of halogen. The dialkyl carbonates are thus formed with almost quantitative selectivity and no deactivation of the catalyst occurs.
摘要:
1,2-Dichlorobenzene can be reacted very selectively under adiabatic reaction conditions to give 3,4-dichloronitrobenzene by intensively mixing 1,2-dichlorobenzene with nitric acid, sulphuric acid and water, simultaneously or successively, in their total amount, using a mixing energy of 1-50 watts per litre of the total reaction mixture, preferably 3-30 W/l, and maintaining a temperature of from 0 to 60° C. during mixing.
摘要:
Hydroxymethyl-cyclopropane (cyclopropyl-methanol) can be obtained in a manner which is both economical and environment-friendly by catalytic hydrogenation of cyclopropanecarboxylic acid alkyl esters under increased pressure at elevated temperature if a chromium-free zinc oxide catalyst is employed as the catalyst.
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.