Abstract: Process for the continuous hydrogenation of a carboxylic acid (I) to an alcohol (II) by means of hydrogen at a temperature of from 100 to 300° C. and a pressure of 10 to 33 MPa abs in a reactor tube through which axial flow occurs and which has a fixed-bed catalyst which is fixed therein and comprises at least one element from the group consisting of Re, Co and Cu, and in which the carboxylic acid (I) to be hydrogenated is present in a liquid mixture (III) comprising the carboxylic acid (I), water and alcohol (II), where the mixture (III) has an acid number of from 0.2 to 25 mg KOH/g and comprises at least 15% by weight of water and at least 20% by weight of alcohol (II) and the flow velocity of the flowing liquid calculated on the basis of the geometric cross-sectional area of the empty, catalyst-free reactor tube is from 10 to 50 m/h.

Abstract: Process for the continuous hydrogenation of a carboxylic acid (I) to an alcohol (II) by means of hydrogen at a temperature of from 100 to 300° C. and a pressure of 10 to 33 MPa abs in a reactor tube through which axial flow occurs and which has a fixed-bed catalyst which is fixed therein and comprises at least one element from the group consisting of Re, Co and Cu, and in which the carboxylic acid (I) to be hydrogenated is present in a liquid mixture (Ill) comprising the carboxylic acid (I), water and alcohol (II), where the mixture (Ill) has an acid number of from 0.2 to 25 mg KOH/g and comprises at least 15% by weight of water and at least 20% by weight of alcohol (II) and the flow velocity of the flowing liquid calculated on the basis of the geometric cross-sectional area of the empty, catalyst-free reactor tube is from 10 to 50 m/h.

Abstract: The present invention relates to a process for hydrogenating oligo- and/or polyesters obtainable by esterifying a DCS with a diol or diol mixture, said hydrogenation being performed in the presence of a catalyst whose catalyst precursor comprises copper oxide, aluminum oxide and at least one oxide of lanthanum, of iron, of tungsten, of molybdenum, of titanium or of zirconium, and to a process for preparing 1,6-hexanediol by catalytically hydrogenating ester mixtures which comprise, as main components, oligo- and polyesters of adipic acid and 6-hydroxycaproic acid, and are obtained by esterifying DCS with diols, especially 1,6-hexanediol or diol mixtures.

Abstract: ?-Hydroxycarboxylic esters and ?-lactones which are suitable as flavors can be prepared by electrochemical reductive cross-coupling of ?,?-unsaturated esters with carbonyl compounds in an undivided electrolysis cell having a cathode composed of lead, lead alloys, cadmium, cadmium alloys, mercury, steel, glassy carbon or boron-doped diamonds and a basic aqueous electrolyte comprising an electrolyte salt which suppresses the cathodic formation of hydrogen.

Abstract: ?-Hydroxycarboxylic esters and ?-lactones which are suitable as flavors can be prepared by electrochemical reductive cross-coupling of ?,?-unsaturated esters with carbonyl compounds in an undivided electrolysis cell having a cathode composed of lead, lead alloys, cadmium, cadmium alloys, mercury, steel, glassy carbon or boron-doped diamonds and a basic aqueous electrolyte comprising an electrolyte salt which suppresses the cathodic formation of hydrogen.

Abstract: ?-Hydroxycarboxylic esters and ?-lactones which are suitable as flavors can be prepared by electrochemical reductive cross-coupling of ?,?-unsaturated esters with carbonyl compounds in an undivided electrolysis cell having a cathode composed of lead, lead alloys, cadmium, cadmium alloys, mercury, steel, glassy carbon or boron-doped diamonds and a basic aqueous electrolyte comprising an electrolyte salt which suppresses the cathodic formation of hydrogen.

Abstract: The present invention relates to a process for preparing plastics using 1,6-hexanediol having an aldehyde content of less than 500 ppm, a process for preparing 1,6-hexanediol having an aldehyde content of less than 500 ppm and also 1,6-hexanediol having an aldehyde content of less than 500 ppm.

Abstract: The invention relates to processes for preparing 1,6-hexanediol and very pure ?-caprolactone from a dicarboxylic acid solution (DCS), comprising the steps of (a) esterification of the DCS with alcohols, (b) partial catalytic hydrogenation of the esters, (c) distillative removal of 1,6-hexanediol and low boilers as the top product, and (d) cyclization of the 6-hydroxycaproic ester present in the bottoms fraction in the presence of a higher-boiling alcohol than caprolactone.

Abstract: The present invention relates to a process for hydrogenating oligo- and/or polyesters obtainable by esterifying a DCS with a diol or diol mixture, said hydrogenation being performed in the presence of a catalyst whose catalyst precursor comprises copper oxide, aluminum oxide and at least one oxide of lanthanum, of iron, of tungsten, of molybdenum, of titanium or of zirconium, and to a process for preparing 1,6-hexanediol by catalytically hydrogenating ester mixtures which comprise, as main components, oligo- and polyesters of adipic acid and 6-hydroxycaproic acid, and are obtained by esterifying DCS with diols, especially 1,6-hexanediol or diol mixtures.

Abstract: A process for preparing 1,6-hexanediol from a carboxylic acid mixture which comprises adipic acid, 6-hydroxycaproic acid and small amounts of 1,4-cyclohexanediols and is obtained as a by-product of the oxidation of cyclohexane to cyclohexanone/cyclohexanol with oxygen or oxygen-comprising gases by water extraction of the reaction mixture, by esterification and hydrogenation to hexanediol, which comprises a) the mono- and dicarboxylic acids present in the aqueous reaction 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) in a second distillation stage, a separation is performed of the bottom product into an ester fraction essentially free of 1,4-cyclohexanediols and a fraction comprising at least the majority of the 1,4-cyclohexanediols, d) the ester fraction from (c) is catalytically hydrogenated and 1,6-hexanediol is obtained in a manner know

Abstract: The present invention relates to a process for preparing plastics using 1,6-hexanediol having an aldehyde content of less than 500 ppm, a process for preparing 1,6-hexanediol having an aldehyde content of less than 500 ppm and also 1,6-hexanediol having an aldehyde content of less than 500 ppm.