Bayer Aktiengesellschaft

Gerhard Darsow

Otto Immel

Gerd-Michael Petruck

Hans-Josef Buysch

Helmut Waldmann

Reinhard Langer

Wilfried Niemeier

Christine Mendoza-Frohn

Ulrich Notheis

Rudolf J Klee

Lutz Frohn

Ludwig Bottenbruch

Hugo Vernaleken

Rudolf Braden

Hans-Helmut Schwarz

Joachim Wank

Eberhard Zirngiebl

Udo Birkenstock

Eckart Reese

Jorg-Dietrich Jentsch

Wolfgang Biedermann

Heinz-Jurgen Alpers

Jurgen Scharschmidt

Christoph Tiburtius

Rudolph Binsack

Wolfgang Dummer

Bernd Pennemann

Paul Schiller

J Urgen Scharschmidt

Epimer-free sugar alcohols can be prepared from the corresponding sugars by catalytic hydrogenation with hydrogen in aqueous solution, the hydrogenation being carried out continuously at a hydrogen pressure of 100 to 400 bar and a reaction temperature of 20 to 70.degree. C. on support-free shaped bodies which are arranged in a fixed bed and are made of pressed powders of metals or alloys of the elements of the iron subgroup of subgroup VIII of the Periodic Table of the Elements together with elements of subgroup IV and/or V. The shaped bodies have a compressive strength of 20 to 220 N and an internal surface area of 10 to 100 m.sup.2 /g.

Process for the hydrogenation of sugars

Ru--Pd halogen-free catalyzers and method for producing cycloaliphatic

In a process for producing aliphatic .alpha.,.omega.-diols comprising 4 to 12 C atoms from aliphatic .alpha.,.omega.-dicarboxylic acids comprising 4 to 12 C atoms, an oligoester of average chain length n=3 to n=4.5 and with an acid number of 40 to 60 mg KOH/g reaction mixture is first formed from a diol and a dicarboxylic acid, which oligoester is thereafter catalytically hydrogenated in the liquid phase. Hydrogenation is carried out continuously at 180 to 250.degree. C. and at an H.sub.2 pressure of 100 to 400 bar, over a pelletised catalyst which is free from Zn oxide and which comprises pressed powders of Cu, Mn and Al oxides with a content of at least one oxide of metals of subgroup VI of the periodic table of the elements (Mendeleev). The amount of H.sub.2 is 20 to 100 times the amount required stoichiometrically.

Process for producing aliphatic diols

Process for producing isocamphyl cyclohexanoles

The sugar alcohols mentioned as title compounds can be prepared from the corresponding sugar in equimolar amounts by catalytic hydrogenation with hydrogen in aqueous solution, the hydrogenation being carried out continuously at an H.sub.2 pressure of 100 to 400 bar and a reaction temperature of 20 to 80.degree. C. using fixed-bed support-free molded bodies composed of compacted powders of alloys of the elements of the iron subgroup of group VIIIA of the periodic table with elements of group IVB and VA. The molded bodies have a compressive strength of 20 to 220 N and an internal surface area of 10 to 95 m.sup.2 /g.

Process for preparing .alpha.-D-glucopyranosido-1,6-mannitol

Maleic anhydride can be hydrogenated to succinic anhydride with particularly high conversion rates by a catalytic liquid-phase hydrogenation with hydrogen, by carrying out the hydrogenation continuously at a pressure of 10 to 400 bar and a reaction temperature of 60 to 180.degree. C. on oxygen-free and support-free shaped bodies, which are arranged in the fixed bed, of compressed powders of the elements of the iron sub-group of group VIII of the Periodic Table, mixed or alloyed with elements of transition group IV and/or V; in addition, hydrogenation-inert elements can be present. The shaped bodies have a compressive strength of 20 to 220 N and an internal surface area of 10 to 100 m.sup.2 /g.

Process for preparing succinic anhydride

To prepare isocamphylcyclohexanols by hydrogenating compounds containing the carbon skeleton of the isocamphylguaiacols or isocamphylphenols, oxygen-free and support-free molded bodies disposed in a fixed bed and made of compacted powders of the elements of the ferrous subgroup of group VIII of the periodic system or their mutual alloys or their alloys with elements of group VIB are used as catalysts; in addition, hydrogenationally inert elements may be present. The molded bodies have a compressive strength of 20 to 250N and an internal surface area of 10 to 90 m.sup.2 /g.

Process for preparing isocamphylcyclohexanols

Dialkyl maleates can be hydrogenated with hydrogen in a catalytic liquid-phase hydrogenation to give dialkyl succinates, wherein the hydrogenation is carried out continuously at a pressure of from 50 to 400 bar and a reaction temperature of from 30 to 160.degree. C. over a fixed bed of oxygen-free and support-free shaped bodies comprising pressed powders of the elements of the iron subgroup of transition group VIII of the Periodic Table of the Elements (Mendeleev) or their alloys or mixtures with one another with additions of elements of transition groups IV and/or V; hydrogenation-inert elements can additionally be present. The shaped bodies have a compressive strength of from 20 to 220N and an internal surface area of from 10 to 100 m.sup.2 /g.

Process for preparing dialkyl succinates

Hydroxymethylcyclopropane is prepared from alkyl cyclopropanecarboxylates by reduction with hydrogen in a process in which use is made of a reduced pelletized catalyst which is obtainable by pressing a mixture of pulverulent copper, zinc and aluminum oxides and subsequent reduction. This process has the advantage that it uses a low-toxicity catalyst which has a long operating life and is particularly suitable for a continuous process and requires relatively low reaction temperatures.

Process for preparing hydroxymethylcyclopropane

Maleic anhydride can be hydrogenated with hydrogen to give succinic anhydride by a catalyzed liquid-phase hydrogenation, by carrying out the hydrogenation continuously at a pressure of 50 to 400 bar and a reaction temperature of 60.degree. to 180.degree. C. on oxygen-free and support-free shaped bodies arranged in the fixed bed, which shaped bodies are made of pressed powders of the elements of the iron subgroup of subgroup VIII of the Periodic Table of the Elements or of their alloys with each other or of their alloys with elements of subgroup VI; in addition, hydrogenation-inert elements can be present. The shaped bodies have a compressive strength of 20 to 250N and an internal surface area of 10 to 90 m.sup.2 /g.

Process for the preparation of succinic anhydride

A description is given of the preparation of hydroxybiphenyl by dehydrogenation of completely or partially hydrogenated precursors using a supported Rh catalyst which additionally contains chromium, manganese and alkali metal and can contain a sulphur compound. The Rh catalyst which can be used according to the invention is prepared from halide-free starting materials. The Rh catalyst is distinguished by a low dependence of the initial selectivity, with the selectivity in the run-in state and the running-in time on the conditions of the reductive pretreatment and requires only short running-in times to reach the optimum state.

Process for preparing hydroxybiphenyl

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).

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Krefeld, Germany

Gerhard Darsow