Bayer Aktiengesellschaft

Gerd-Michael Petruck

Gerhard Darsow

Reinhard Langer

Erich Klauke

Helmut Waldmann

Otto Immel

Adolf Wissner

Wilfried Niemeier

Paul R Wambach, Deceased

Hermann Hagemann

Horst Jager

Heinz-Jurgen Alpers

Raimund Wambach

Sigurd Hartung

The invention relates to a process for the preparation of d,l-menthol by catalytic hydrogenation of compounds which have the carbon skeleton of menthane containing at least one double bond and are 3-substituted by oxygen and/or of menthone or isomenthone or mixtures of such compounds using hydrogen at temperatures of 100 to 200&deg; C. and at hydrogen partial pressures between 2 and 50 bar and/or by rearrangement of menthol stereoisomers in the presence of hydrogen at temperatures of 0 to 140&deg; C. and at hydrogen partial pressures between 0.1 and 20 bar in the presence of noble-metal-containing catalysts.

Process for the preparation of d,I-menthol

A low-pressure process for the hydrogenation of aromatic amines to give the corresponding symmetrical dicycloaliphatic amines in the presence of rhodium catalysts which are unmodified or modified by Ir, Ru, Os, Pd and/or Pt or mixtures of these metals, on supports modified by oxides of Cr, Mo, W, Mn and/or Re or mixtures of these oxides.

Process for preparing dicycloaliphatic amines

The present invention relates to a low-pressure process for hydrogenating aromatic amines to give the corresponding cycloaliphatic amines in the presence of rhodium catalysts.

Process for preparing cycloaliphatic amines

A high-pressure process for hydrogenating aromatic amines to give mixtures of the corresponding cycloaliphatic amines and dicycloaliphatic amines in variable ratios in the presence of rhodium catalysts.

Process for preparing variable mixtures of cyclohexyl-amine and

A process is described for preparing D,L-menthol by catalytic rearrangement of optically active D-menthol in the presence of hydrogen at temperatures of from 200 to 350.degree. C. and under pressures of from 50 to 350 bar over fixed-bed catalysts comprising support-free reduced shaped bodies of pressed powders of nickel, manganese, alkaline earth metal (hydr)oxides and optionally (hydr)oxides of elements of transition groups V and/or VI of the Periodic Table.

Process for preparing D,L-menthol from D-menthol

A continuous process is described for the preparation of D,L-menthol by catalytic hydrogenation of compounds which have the carbon skeleton of p-menthane containing at least one double bond and are 3-substituted by oxygen using hydrogen and/or by rearrangement of stereoisomers of menthol in the presence of hydrogen at temperatures of 150.degree. to 230.degree. C. and at pressures of 25 to 350 bar on fixed-bed catalysts made of support-free reduced shaped bodies made of pressed powders of cobalt (hydr)oxide, manganese (hydr)oxide, alkaline earth metal (hydr)oxides and, optionally, (hydr)oxides of elements of subgroup V and/or VI of the Periodic Table of the Elements.

Process for the preparation of D,L-menthol

For the continuous preparation of a mixture of amino-methyl-cyclohexanes and diamino-methyl-cyclohexanes by catalytic hydrogenation of diamino-toluenes with hydrogen at temperatures of from 150.degree. to 260.degree. C. and an H.sub.2 pressure of from 20 to 500 bar, use is made of a fixed-bed catalyst comprising ruthenium on an Al.sub.2 O.sub.3 support treated with compounds of rare earth metals, of manganese and alkali metal hydroxides or alkaline earth metal hydroxides.

Process for preparing a mixture of amino-methyl-cyclohexanes and

For the continuous preparation of a mixture of amino-methyl-cyclohexanes and diamino-methyl-cyclohexanes by catalytic hydrogenation of diamino-toluenes with hydrogen at temperatures of from 150.degree. to 260.degree. C. and an H.sub.2 pressure of from 20 to 500 bar, use is made of reduced support-free catalysts which are produced from pressed powders of cobalt, manganese, copper and alkaline earth metal (hydr)oxides, with or without a content of at least one (hydr)oxide of metals of transition group V and/or VI of the Periodic Table of the Elements (Mendeleev).

In the preparation of a mixture of cyclohexylamine and dicyclohexylamine by catalytic hydrogenation of aniline at elevated temperature and elevated H.sub.2 pressure, use is made of reduced, support-free catalysts which comprise pressed element (hydr)oxide powders of Co, Mn, alkaline earth metals and element (hydr)oxide powders of elements of transition groups V and/or VI of the Periodic Table.

Process for preparing a mixture of cyclohexylamine and dicyclohexylamine

To prepare a mixture of cyclohexylamine and dicyclohexylamine by catalytic hydrogenation of aniline at elevated temperature and elevated H.sub.2 pressure, the catalyst system used comprises two reduced, unsupported catalysts A and B which are prepared from pressed element (hydr)oxide powders. Catalyst A comprises one or more of Fe, Co, Ni, also Mn, Cu and one or more of Ca, Sr, Ba. Catalyst B comprises one or more of Fe, Co, Ni, also Mn, Si and Mg.

In a process for the preparation of aliphatic .alpha.,.omega.-diols of 4 to 12 carbon atoms from aliphatic .alpha.,.omega.-dicarboxylic acids of 4 to 12 carbon atoms, an oligo ester is first of all formed from diol and dicarboxylic acid and is subsequently subjected to catalytic hydrogenation in the liquid phase. The hydrogenation is carried out continuously at from 180.degree. to 250.degree. C. and at an H.sub.2 pressure of from 100 to 400 bar over a catalyst in piece form comprising compressed powders of Cu, Zn and Al oxides which do or do not contain at least one oxide of metals of the iron group of the Periodic Table of the Elements (Mendeleev) or of manganese. The quantity of H.sub.2 is from 20 to 100 times the stoichiometrically required quantity.

Process for the preparation of aliphatic .alpha., .omega.-diols

A Pd catalyst in which an .alpha.- or .gamma.-Al.sub.2 O.sub.3 as support is first treated with at least one compound of the rare earth metals and with at least one compound of manganese and then with at least one palladium compound is suitable for the preparation of a mixture of optionally substituted cyclohexylamine and optionally substituted dicyclohexylamine by hydrogenation of a correspondingly substituted aniline.

Palladium catalyst and its use in the preparation of a mixture of

Optionally substituted cyclohexylamine and optionally substituted dicyclohexylamine can be obtained by catalytic hydrogenation of optionally substituted aniline, a catalyst being employed which contains ruthenium, palladium or a mixture of both metals, which are applied to a support of niobic acid or tantalic acid or a mixture of both. The catalyst contains the noble metal(s) in a total amount from 0.05 to 5% by weight, relative to the total weight of the catalyst. In the case of the use of both noble metals, their weight ratio to one another is 1:9-9:1.

Process for the preparation of a mixture of cyclohexylamine and

A process for the preparation of a trichlorobenzene by chlorination of o-dichlorobenzene in the presence of a catalyst is disclosed. The catalyst comprises aluminum chloride. Preferably an iron or iron chloride containing aluminum chloride catalyst is employed.

Process for the preparation of trichlorobenzenes

A process for the preparation of 2-chlor-4-nitrotoluene is disclosed by chlorination of 4-nitrotoluene in the presence of iodine. The resultant 2-chloro-4-nitrotoluene is a valuable intermediate for the preparation of herbicides.

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Erkrath, Germany

Gerd-Michael Petruck