Abstract: Disclosed is a catalyst for hydrogenating a carboxylic acid, comprising an activated carbon having carried thereon an active metal species comprising ruthenium and tin, wherein the activated carbon is produced by subjecting a carbonaceous material to activation treatment using zinc chloride, followed by calcination. Also disclosed is a catalyst for hydrogenating a carboxylic acid, comprising an activated carbon having carried thereon an active metal species comprising ruthenium and tin, wherein the activated carbon, prior to having carried thereon the active metal species, exhibits specific pore characteristics wherein, especially, the pore volume with respect to pores each having a radius of from 10 to 100 Å is from 0.5 to 2.0 cm3/g.

Abstract: Maleic acid and/or other hydrogenatable precursors are hydrogenated in the presence of a noble metal catalyst to 1,4-butanediol. The production and yields of 1,4-butanediol are enhanced by the addition of iron to the hydrogenatable precursor feed.

Abstract: A method for preparation of alcohols by catalytic hydrogenation of carbonyl compounds with hydrogen or hydrogen-containing gases in the presence of a hydrogenation catalyst of Raney type, where the catalyst is used in the form of hollow bodies, Preferred as catalytically active components are nickel, cobalt, copper, iron, platinum, palladium or ruthenium.

Abstract: A process for the preparation of butane triols is provided. In the process, a malic acid diester is reduced with sodium borohydride in the presence of an ether and an alcohol. Preferably, the malic acid diester is an ethyl or methyl ester, the ether is tetrahydrofuran or bis(2-methoxyethyl) ether (diglyme), and the alcohol comprises ethanol. Advantageously, the reaction is carried out at ambient temperature.

Abstract: Methods and compositions for reactions of hydrogen over a Re-containing catalyst with compositions containing a 5-carbon sugar, sugar alcohol, or lactic acid are described. It has been surprisingly discovered that reaction with hydrogen over a Re-containing multimetallic catalyst resulted in superior conversion and selectivity to desired products such as propylene glycol. A process for the synthesis of PG from lactate or lactic acid is also described.

Abstract: A process for preparing an 1,3-alkanediol from a 3-hydroxyester includes hydrogenating a 3-hydroxyester in an alcohol-containing solvent in the presence of a hydrogenation catalyst prepared by adding an alkaline precipitator to an aqueous solution containing a copper salt to form particles, and then aging the particles following addition of colloidal silica thereto. Novel hydrogenation catalysts so prepared are also disclosed.

Abstract: A method for catalytically reducing the carboxylic acid group of hydroxycarboxylic acids to a hydroxyl group is disclosed. An organic compound having an &agr;-hydroxyl group and at least one carboxylic acid group is contacted with a catalyst in the presence of hydrogen to yield a reduced product having at least two hydroxyl groups, the carboxylic acid group having been converted into one of the hydroxyl groups. The catalytic process may be conducted at hydrogen pressures of less than about 50 atm and is particularly suited for converting (&agr;-hydroxycarboxylic acids, such as lactic acid or glycolic acid, to 1,2-dihydroxy alkanes, such as 1,2-propanediol or ethylene glycol, using zero valent copper. The catalyst may be supported on silica, and the hydroxyl groups on the silica may be capped with hydrophobic groups including alkyl groups and silanes, such as trialkylsilanes.

Abstract: A process for the preparation of 1,6-hexanediol and 6-hydroxycaproic acid or esters thereof by catalytic hydrogenation of adipic acid, adipic acid monoesters or adipic acid diesters or streams of starting material which contain adipic acid or esters thereof as essential constituents, in which the bottom product obtained in the distillation of the hydrogenation product, following removal of the hexanediol and hydroxycaproic acid or esters thereof, and essentially comprises oligomeric esters of 6-hydroxycaproic acid, is recycled to the hydrogenation, and the resulting mixture of starting material and recycle stream is reacted at from 100 to 300°C., at from 10 to 300 bar in the liquid phase and at a molar ratio of carboxyl groups to be hydrogenated to hydrogen in the reactor of from 1:5 to 1:100 on hydrogenation catalysts is described.

Abstract: A method for catalytically reducing the carboxylic acid group of hydroxycarboxylic acids to a hydroxyl group is disclosed. An organic compound having an &agr;-hydroxyl group and at least one carboxylic acid group is contacted with a catalyst in the presence of hydrogen to yield a reduced product having at least two hydroxyl groups, the carboxylic acid group having been converted into one of the hydroxyl groups. The catalytic process may be conducted at hydrogen pressures of less than about 50 atm and is particularly suited for converting &agr;-hydroxycarboxylic acids, such as lactic acid or glycolic acid, to 1,2-dihydroxy alkanes, such as 1,2-propanediol or ethylene glycol, using zero valent copper. The catalyst may be supported on silica, and the hydroxyl groups on the silica may be capped with hydrophobic groups including alkyl groups and silanes, such as trialkylsilanes.

Abstract: A process for producing 1,6-hexanediol by hydrogenation of adipic esters and/or 6-hydroxycaproic esters in the gas phase at elevated temperature and elevated pressure in the presence of chromium-free catalysts comprises hydrogenating a) over a catalyst comprising copper, manganese and aluminum as essential constituents or over Raney copper, b) at a temperature of from 150 to 230° C. and a pressure of from 10 to 70 bar, c) at a molar ratio of hydrogen to ester to be hydrogenated within the range from 150:1 to 300:1, and d) at a catalyst space velocity of from 0.01 to 0.3 kg of C6 ester per liter of catalyst per hour.

Abstract: The present invention provides a process for production of propylene glycol with high yield and selectivity in an aqueous reaction mixture of lactic acid and hydrogen with an essentially pure elemental ruthenium catalyst on an inert support at elevated pressure and temperature. In particular, the present invention provides a process wherein the catalyst is a ruthenium salt deposited on a microporous support, reduced to ruthenium on the support with hydrogen, and oxidized in the presence of oxygen to provide a ruthenium oxide surface on the surface of the ruthenium metal and wherein the catalyst is maintained in the surface oxidized state until it is reduced with hydrogen prior to the reaction process.

Abstract: A process for the separation by distillation of a mixture of 1,4-butanediol and at least one 4-hydroxybutyraldehyde, its cyclic hemiacetal and its cyclic full acetals with at least one further alcohol by carrying out the distillation in the presence of an alkaline compound. The mixture to be separated preferably contains a cyclic full acetal of 4-hydroxybutyraldehyde with a further alcohol which has a lower boiling point than butanediol and also the further alcohol in free form. The process is particularly suitable for the separation by distillation of mixtures formed in the hydrogenation of maleic acid derivatives.

Abstract: The invention relates to catalysts containing ruthenium and at least one other metal having an atomic number in the range of from 23 to 82 prepared by (a) mixing a suspension of a ruthenium compound having a specific surface area in the range of from 50 to 300 m2/g with a solution of at least one metal compound in which at least one such metal compound contains a metal different from ruthenium and has an atomic number in the range of from 23 to 82, and (b) treating the mixture of the suspension and the solution with a reducing agent.

Abstract: A carbonylation process, wherein formaldehyde or a derivative thereof is reacted with carbon monoxide in the presence of a catalyst composition including: a) an acidic compound with pKa value below −1, and b) a sulfone.

Abstract: The invention relates to a process for the preparation of optically active alcohols from optically active carboxylic acids by reducing an optically active carboxylic acid with hydrogen in the presence of a catalyst comprising ruthenium and at least one further metal or transition metal having an atomic number in the range of from 23 to 82.

Abstract: A process for preparing 1,4-butanediol and, if desired, &ggr;-butyrolactone and THF by oxidizing butane or benzene to form a product stream including maleic anhydride, absorbing maleic anhydride from the product stream with a high-boiling inert solvent in an absorption stage to give a liquid absorption product, esterifying the liquid absorption product with a C1-C5 esterifying alcohol in an esterification stage to form an esterification product comprising the corresponding diester and high-boiling inert solvent, then hydrogenating the esterification product to give a hydrogenation product which comprises the products of value, 1,4-butanediol and, if desired, &ggr;-butyrolactone and tetrahydrofuran and the esterifying alcohol and which is separated by distillation into the products of value and the esterifying alcohol, and recycling the esterifying alcohol to the esterification zone, which comprises separating the esterification product into the diester and the inert solvent by distillation under reduced press

Abstract: A process for preparing an 1,3-alkanediol through carbonylation of an epoxide derivative includes the steps of (a) reacting an epoxide derivative with alcohol and carbon monoxide in a solvent at a temperature from about 30 to about 150° C. and at a pressure from about 50 to about 3000 psig in the presence of a catalyst system including an effective amount of a cobalt catalyst and an effective amount of a promoter to afford a reaction mixture including a 3-hydroxyester or derivative thereof in an amount of from 2 to about 95% by weight, (b) separating the reaction product and solvent from the catalyst and promoter, (c) reacting said reaction product and solvent with hydrogen at a temperature from about 30 to about 350° C. and at a pressure from about 50 to about 5000 psig in the presence of a catalyst system for hydrogenation to prepare a hydrogenation product mixture including a 1,3-alkanediol, and (d) recovering the 1,3-alkanediol from the hydrogenation product mixture.

Abstract: Hexanediol is prepared by hydrogenating dialkyl adipates or mixtures which contain a dialkyl adipate as the essential component and organic halogen compounds as impurities, by a process in which, before the hydrogenation, the dialkyl adipates or the mixtures containing dialkyl adipates are passed at from 50 to 250° C. and from 1 to 100 bar over copper catalysts which have a copper content, calculated as CuO, of from 0.5 to 80% by weight, a surface area of from 5 to 1500 m2/g, a porosity of from 0.05 to 1.5 cm3/g and a copper surface area of from 0.1 to 20 m2/g, in order to remove the organic halogen compounds.

Abstract: The present invention provides a process for preparation of low molecular weight polyols from high molecular weight polyols in a hydrogenolysis reaction under elevated temperature and hydrogen pressure. The process comprises providing in a reaction mixture the polyols, a base, and a metal catalyst prepared by depositing a transition metal salt on an inert support, reducing the metal salt to the metal with hydrogen, and passivating the metal with oxygen, and wherein the catalyst is reduced with hydrogen prior to the reaction. In particular, the process provides for the preparation of glycerol, propylene glycol, and ethylene glycol from sugar alcohols such as sorbitol or xylitol. In a preferred process, the metal catalyst comprises ruthenium which is deposited on an alumina, titania, or carbon support, and the dispersion of the ruthenium on the support increases during the hydrogenolysis reaction.

Abstract: A process for preparing 1,6-hexanediol from a carboxylic acid mixture obtained as by-product in the oxidation of cyclohexane to cyclohexanone/cyclohexanol with oxygen or oxygen-comprising gases and by aqueous extraction of the reaction mixture and comprising adipic acid, 6-hydroxycaproic acid and small amounts of 1,4-cyclohexanediols by esterification of the acids and hydrogenation, by a) reacting the mono- and dicarboxylic acids in the aqueous dicarboxylic acid mixture with a low molecular weight alcohol to form the corresponding carboxylic esters, b) conducting a first distillation to remove excess alcohol and low boilers from the esterification mixture obtained, c) conducting a second distillation to separate the bottom product into an ester fraction which is essentially free from 1,4-cyclohexanediols and a fraction which includes at least the larger proportion of the 1,4-cyclohexanediols, d) subjecting the ester fraction essentially free from 1,4-cyclohexanediols to a catalytic hydrogenation, and e)

Abstract: The invention relates to a method of producing xylitol and erythritol from arabinoxylan-containing material. According to the invention, the arabinoxylan-containing material is hydrolyzed and xylose and arabinose are separated from the obtained hydrolysate, whereafter the xylose is reduced to xylitol, and the xylitol is recovered, and the arabinose is subjected to alkaline oxidation to obtain erythronic acid which is reduced to erythritol, and the erythritol is recovered.

Abstract: Process for the production of tetrahydrofuran, gammabutyrolactone and butanediol starting from maleic anhydride esters, consisting of two subsequent hydrogenations.

Abstract: A process for the production of at least one C4 compound selected from 1,4-butanediol, gamma-butyrolactone and tetrahydrofuran, in which a solution of maleic anhydride in a high boiling ester is esterified with a C1 to C4 alcohol to form the corresponding maleate ester which is hydrogenated to form the at least one C4 compound. The specified high boiling ester has a boiling point which is about 30 degrees C. higher than that of the di-(C1-C4 alkyl)maleate.

Abstract: Noble metal, particularly ruthenium, Raney catalysts which can hydrogenate (1) aromaticity-exhibiting ring portions of organic compounds, (2) carboxylic acids and their ester portions (carbonyl ester groups), (3) ring portions and carboxylic acid or their ester groups in compounds having such ring portions and carboxylic acid or their ester portions, and (4) ring portions and nitrile groups of aromatic nitrile compounds and methods for the preparation of corresponding hydrogenated compounds. The methods allow preparation of hydrogenated compounds having hydrogenated aromatic ring portions, hydrogenated carbonyl ester groups, hydrogenated aromatic ring and carbonyl ester groups, or hydrogenated aromatic rings and nitrile groups under milder hydrogen pressure and temperature conditions than the conventional catalysts.

Abstract: A carbonyl compound or a mixture of two or more carbonyl compounds is catalytically hydrogenated in the presence of a Raney copper catalyst in the form of nuggets.

Abstract: A process is described for the production of butane-1,4-diol, &ggr;-butyrolactone and/or tetrahydrofuran. A vaporous stream containing maleic anhydride, water, and carbon oxides is contact in an absorption zone with a high boiling ester as solvent to form a solution of maleic anhydride in the high boiling ester which has a boiling point at the atmospheric pressure at least about 30° C. higher than that of maleic anhydride and is selected from di-(C1 to C4 alkyl) esters of alkyl dicarboxylic acids containing up to 3 carbon atoms, mono- and di-(C10 to C18 alkyl) esters of maleic acid, fumaric acid, succinic acid, and mixtures thereof, (C1 to C4 alkyl) esters of naphthalene-monocarboxylic acids, tri-(C1 to C4 alkyl) esters of aromatic tricarboxylic acids, and di-(C1 to C4 alkyl) esters of isophthalic acid.

Abstract: In a process for preparing aliphatic alcohols by hydrogenating aliphatic carboxylic acids or anhydrides or esters thereof or lactones in the presence of a catalyst comprising Pt and Re, in the form of the metal or an oxide in each case, the catalyst further comprises at least one further element from the groups 5 to 12 and 14 and the lanthanides of the Periodic Table of the Elements in the form of the metal or an oxide.

Abstract: Isobutylene glycol is produced with a high yield by catalytically reducing methyl hydroxyisobutyrate in the presence of a catalyst containing at least one of copper and ruthenium. The reduction of methyl hydroxyisobutyrate in the presence of the specific catalyst involves selective reduction of only ester group.

Abstract: Process for the production of 1,4-butanediol by mixed phase catalytic hydrogenation of gamma-butyrolactone, succinic anhydride esters, or mixtures thereof.

Abstract: 1,3-Propanediol is prepared in good yield by hydrogenation of methyl 3-hydroxypropionate in the presence of a copper zinc oxide hydrogenation catalyst. The use of the copper zinc oxide hydrogenation catalyst enables greater productivity in an overall process for preparing 1,3-propanediol from ethylene oxide via methyl 3-hydroxypropionate intermediate.

Abstract: A process for the production of at least one C.sub.4 compound selected from butane-1,4-diol, .gamma.-butyrolactone and tetrahydrofuran comprises contacting a vaporous stream containing maleic anhydride vapour, water vapour, and carbon oxides in an absorption zone with a high boiling organic solvent thereby to form a solution of maleic anhydride in the high boiling organic solvent. Maleic anhydride in this solution is reacted under esterification conditions in an esterification zone with a C.sub.1 to C.sub.4 alkanol to form a solution of the corresponding di-(C.sub.1 to C.sub.4 alkyl) maleate in the high boiling solvent. This solution of the di-(C.sub.1 to C.sub.4 alkyl) maleate in the high boiling solvent is contacted with a gaseous stream containing hydrogen thereby to strip di-(C.sub.1 to C.sub.4 alkyl) maleate therefrom and to form a vaporous stream comprising hydrogen and di-(C.sub.1 to C.sub.4 alkyl) maleate.

Abstract: Disclosed are catalysts in powdered form comprising a major amount of the oxides of a first metal selected from copper or zinc, a second metal selected from chromium, molybdenum, tungsten and vanadium, and optionally, a minor amount of the oxide of a promoter metal selected from the group consisting of manganese, barium, zinc, nickel, cobalt, cadmium, iron and any combination thereof provided that the promoter metal is not zinc if the first metal is zinc, wherein the average particle diameter of the powder is from about 6 to about 20 microns; and the particle surface area is from about 20 to about 70 m.sup.2 /g. Also disclosed is a process for preparing such catalysts and a process for hydrogenating aldehydes, ketones, carboxylic acids and carboxylic acid esters with catalysts of the type described.

Abstract: 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.

Abstract: An improved two step (dual stage catalysis) aqueous hydrogenation process and a novel trimetallic hydrogenation catalysts consisting essentially of highly dispersed, reduced ruthenium and rhenium metals in the presence of a third metal tin on carbon support particular useful in the second stage of the process. Such process and catalyst exhibit high conversion rates in aqueous solution hydrogenation of hydrogenatable precursors (e.g., maleic acid, succinic acid, corresponding esters, .gamma.-butyrolactone, etc.) to tetrahydrofuran, .gamma.-butyrolactone, 1,4-butanediol and mixtures thereof wherein the relative molar ratio of 1,4-butanediol to tetrahydrofuran products being produced can be controlled.

Abstract: 1,6-Hexanediol is prepared from a carboxylic acid mixture comprising adipic acid, 6-hydroxycaproic acid and small amounts of 1,4-cyclohexanediols which is obtained as a by-product in the oxidation of cyclohexane to cyclohexanone/cyclohexanol by water extraction of the reaction mixture, by esterification of the acids and hydrogenation whereina) the monocarboxylic and dicarboxylic acids present in the aqueous dicarboxylic acid mixture are reacted with a low molecular weight alcohol to give the corresponding carboxylic esters,b) the resulting esterification mixture is freed of excess alcohol and low boilers in a first distillation stage,c) the bottoms are fractionated in a second distillation stage to give an ester fraction essentially free of 1,4-cyclohexanediols and a fraction comprising at least the major part of the 1,4-cyclohexanediols,d) the ester fraction essentially free of 1,4-cyclohexanediols is catalytically hydrogenated ande) in a pure distillation stage, 1,6-hexanediol is isolated from the hydrogena

Abstract: 1,6-hexanediol and .epsilon.-caprolactone are prepared from a carboxylic acid mixture comprising adipic acid, 6-hydroxycaproic acid and small amounts of 1,4-cyclohexanediols which is obtained as a by-product in the oxidation of cyclohexane to cyclohexanone/cyclohexanol using oxygen or oxygen-containing gases by water extraction of the reaction mixture, by esterifying and hydrogenating a substream to give hexanediol and cyclizing 6-hydroxycaproic esters to give caprolactone.

Abstract: A process for preparing a difunctional compound having high enantiomeric purity that is a 1,2-, 1,3-, or 1,4-diol, dithiol, or mercapto alcohol from an optically active starting material that includes an .alpha.-, .beta.-, or .gamma.-hydroxy (or mercapto) aldehyde, ketone, ester, or amide is described. The process is carried out in an anhydrous solvent medium and comprises (1) reducing the starting material with a metal hydride (e.g., sodium borohydride), (2) adding a coreactant that is substituted by at least one, but preferably two, hydroxyl or mercapto groups (e.g., pyrocatechol), and (3) directly distilling the product from the reaction medium. The coreactant preferably has a higher boiling point at normal atmospheric pressure than the difunctional compound. The difunctional compounds are used as reactants for syntheses of agrochemicals or pharmaceuticals, or as precursors for polymers.

Abstract: The present invention is based upon the surprising discovery that a 5-carbon compound selected from the group of 4-oxopentanoic acid, at least one lactone of 4-oxopentanoic acid, and combinations thereof, may be hydrogenated with a bimetallic catalyst of a noble metal in combination with a second metal and preserve the pendant methyl group. It was further unexpectedly discovered that the same conditions of bimetallic catalyst in the presence of hydrogen are useful for catalyzing the different intermediate reactions for example angelicalactone to gamma-valerolactone and gamma-valerolactone to 1,4-pentanediol. Finally, it was surprising that levulinic acid could be converted to 2-methyltetrahydrofuran with heating in the presence of the bimetallic catalyst and hydrogen in a single process vessel. The method of the present invention unexpectedly produced a fuel or fuel component having 2-methyltetrahydrofuran either in a yield greater than 4.5 mol % or in combination with alcohols.

Abstract: A method is disclosed for producing a pentitol. The disclosed method more particularly relates to producing arabinitol from hexoses, e.g. galactose and/or glucose, and/or fructose, or lactose hydrolysate, or invert sugar, or starch hydrolysates. The hexose is oxidatively decarboxylated to a C.sub.5 -aldonic acid which is thereafter catalytically hydrogenated to obtain the desired arabinitol.

Abstract: Preparation of 4-hydroxy substituted butyrolactones is described. A process for the preparation of 3-hydroxybutyrolactone, 1,2,4-trihydroxybutane and 3,4-dihydroxy acid methyl ester from malic acid is particularly described. The preparation of 4-hydroxymethyl-4-hydroxybutyric acid -1-methyl ester and 4-hydroxymethyl butyrolactone is particularly described. The compounds are intermediates to various pharmaceutical and agricultural products.

Abstract: The present invention provides a hydrogenation catalyst precursor which does not bring about a problem of environmental pollution involved in copper-chromium catalysts and has a high activity, a high durability and a high selectivity as compared with those of conventional copper-iron-aluminum catalysts, a hydrogenation catalyst obtained by reducing the same, and a production process for alcohols using the above hydrogenation catalyst. The hydrogenation catalyst precursor described above comprises copper, iron and aluminum and containing as a principal component a compound oxide of copper, iron and aluminum in which an atomic ratio Cu:Fe:Al is 1:(0.02 to 0.4):(1.0 to 4.0) and which has a copper-aluminum spinel structure.

Abstract: The present invention discloses a chemical method for producing meso-erythritol. The method comprises catalytic hydrogenation of tartaric acid. The tetritol mixture resulting from the hydrogenation can be separated into its components. Alternatively selected components can be isomerized prior to such a separation.

Abstract: Optically active alcohols are prepared by reducing optically active carboxylic acids with hydrogen in the presence of ruthenium catalysts.

Abstract: In the process of the present invention for producing diol compounds by esterifying a carboxylic acid mixture collected from a reaction product mixture of a liquid phase oxidation of cyclohexane with air and hydrogenate-decomposing the resultant esterification product mixture with hydrogen, the hydrogenate-decomposition is carried out by using a combined catalyst which includes a catalyst (A) including, as principal components, copper oxide and zinc oxide and a catalyst (B) including copper oxide and iron oxide carried on aluminum oxide, does not include chromium, has a high catalytic activity and can be easily separated by filtering, and the combined catalyst is collected from the hydrogenate-decomposition reaction product mixture by filtering it.

Abstract: Maleic anhydride (MA) is first reacted with 1,4-butanediol in a molar ratio of 1,4-butanediol:MA=1.1-2:1 to give an oligoester which is subsequently hydrogenated with excess hydrogen at 100-400 bar in two hydrogenation steps to give 1,4-butanediol. The first hydrogenation step is carried out at 60.degree.-130.degree. C. over a support-free catalyst of compacted metal powder of Ni, Fe, Co or mixtures thereof; the second hydrogenation step is carried out at 190.degree.-230.degree. C. over a reduced, support-free catalyst of compacted powders of copper oxides, ZnO and Al.sub.2 O.sub.3 containing proportions of oxides of Ni, Fe, Co or mixtures of a plurality thereof. A temperature difference of 60.degree.-130.degree. C. is set between the two hydrogenation steps.

Abstract: Maleic acid, maleic anhydride or other hydrogenatable precursor are catalytically hydrogenated to 1,4-butanediol and tetrahydrofuran. It has been discovered that high yields of 1,4-butanediol are achieved when the hydrogenation catalyst comprises at least one noble metal of Group VIII of the Periodic Table and at least one of rhenium, tungsten or molybdenum on a carbon support wherein the carbon support has been contacted with an oxidizing agent prior to the deposition of the metals. This hydrogenation catalyst is prepared by the steps of(i) oxidizing the carbon support by contacting the carbon support with an oxidizing agent,(ii) impregnating in one or more impregnation steps comprising contacting the carbon support with a source of Group VIII metal and at least one metal selected from the group consisting of rhenium, tungsten and molybdenum being in at least one solution,(iii) after each impregnation step, drying at a temperature under about 150.degree. C.

Abstract: 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.

Abstract: A method for preparing a copper-containing hydrogenation reaction catalyst includes the step of reducing a formed precursor of a copper-containing hydrogenation reaction catalyst with hydrogen gas or a mixture of hydrogen and inert gas by liquid phase reduction in a stream of a solvent. The reductive activation is carried out by the two steps of performing the first stage of liquid phase reduction by which the catalyst precursor is activated in the temperature range of from 20.degree. to 140.degree. C. so that at least 10% by weight of the copper oxide contained in the catalyst precursor can be reduced by the time when the temperature passes 140.degree. C., and then performing the second stage of liquid phase reduction by which the catalyst precursor is further activated in the temperature range of from 140.degree. to 250.degree. C. The catalyst thus obtained has markedly improved catalytic activity and selectivity.

Abstract: New flexible polyurethane foams are described, suitable for use in the interior linings of cars, with a reduced fogging effect, whose content by weight of the cyclic adipate of diethylene glycol, 8,13-dioxo-1,4,7-trioxacyclotridecane, is less than 0.25% and preferably less than 0.17%. Also described are polyester polyols, suitable for preparing these polyurethane foams, whose content by weight of the cyclic adipate of diethylene glycol, 8,13-dioxo-1,4,7-trioxacyclotridecane, is less than 0.4% and preferably less than 0.25%.

Abstract: A method for producing xylitol from D-glucose, D-fructose, D-galactose or mixtures thereof, characterized in that it comprises the steps of:a. oxidation of the starting material to an intermediate that consists mainly of L-xylonic acid, D-arabinonic acid, D-lyxonic acid or a mixture of at least two of said acids, whereby said acids are free or in the form of their salts, lactones or O-formyl derivatives;b. treatment of said intermediate with a hydrogenation catalyst and hydrogen gas in one or several steps to a product consisting mainly of xylitol or a mixture of xylitol, arabinitol and ribitol;c. and, if necessary, separation of xylitol from said product and, if said product consist mainly of said mixture of pentitols, feeding of the fractions of arabinitol and ribitol back to the preceding reaction step b.