Abstract: A process is provided for recovering components from a low boiler mixture which is obtained in the distillation of hydrogenation effluents from the preparation of polymethylols, by multistage distillation of the low boiler mixture having a tertiary amine, water, methanol, a polymethylol, a methylolalkanal, an alcohol and an alkanal with a methylene group in the alpha position to the carbonyl group. A first distillation stage involves separating the low boiler mixture into a higher-boiling, predominantly water-rich fraction and into a lower-boiling aqueous organic fraction having the tertiary amine. A second distillation stage involves separating the aqueous organic fraction from the first distillation stage into a predominantly amine-containing fraction and a further amine-depleted fraction. The tertiary amine is trimethylamine or triethylamine and the bottom temperature in the second distillation stage is at least 110° C.

Abstract: The present invention relates to a process for distilling an aqueous polymethylol mixture which comprises a polymethylol of the formula (I) (HOCH2)2—C—R2??(I) in which each R is independently a further methylol group or an alkyl group having 1 to 22 carbon atoms or an aryl or aralkyl group having 6 to 22 carbon atoms, a tertiary amine, water and the adduct of tertiary amine and formic acid (amine formate), which comprises performing the distillation in a distillation column which is connected at the bottom to an evaporator, the bottom temperature being above the evaporation temperature of the monoester of formic acid and polymethylol (polymethylol formate) which forms during distillation. The present invention further relates to a composition comprising polymethylol and 1 to 10 000 ppm by weight of polymethylol formate, and to the use thereof.

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: The present invention relates to a process for purifying crude polymethylol which comprises polymethylol of the formula (I) (HOCH2)2—C—R2??(I) in which each R is independently a further methylol group or an alkyl group having 1 to 22 carbon atoms or an aryl or aralkyl group having 6 to 22 carbon atoms, and also hydroxy acid of the formula (IV) in which each R is independently as defined above, which comprises performing the purification in a distillation column, the bottom of the distillation column being connected to an evaporator with a short residence time. The present invention further relates to a composition comprising polymethylol and 1 to 10 000 ppm by weight of an ester of polymethylol and of a hydroxy acid and to the use thereof.

Abstract: The present invention provides a process for preparing ?-caprolactone in a purity of more than 99% by cyclizing 6-hydroxycaproic esters in the liquid phase at from 150 to 400° C. and from 1 to 1020 hPa abs., and removing and condensing the compounds which are volatile under cyclization conditions, which comprises thermally treating the remaining bottom product of the cyclization in at least one further reactor, removing and condensing volatile compounds and obtaining ?-caprolactone by distillation from the condensates.

Abstract: The invention relates to a process for preparing ?-caprolactone from 6-hydroxycaproic ester in the gas phase in the presence of activated carbon as a catalyst and subsequent distillation.

Abstract: The present application relates to an improved process for preparing 6-hydroxycaproic esters from the by-product mixtures which are obtained in the oxidation of cyclohexane to cyclohexanol and cyclohexanone with oxygen or oxygen-comprising gas mixtures.

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: The present invention relates to a process for distilling an aqueous polymethylol mixture which comprises a polymethylol of the formula (I) (HOCH2)2—C—R2??(I) in which each R is independently a further methylol group or an alkyl group having 1 to 22 carbon atoms or an aryl or aralkyl group having 6 to 22 carbon atoms, a tertiary amine, water and the adduct of tertiary amine and formic acid (amine formate), which comprises performing the distillation in a distillation column which is connected at the bottom to an evaporator, the bottom temperature being above the evaporation temperature of the monoester of formic acid and polymethylol (polymethylol formate) which forms during distillation. The present invention further relates to a composition comprising polymethylol and 1 to 10 000 ppm by weight of polymethylol formate, and to the use thereof.

Abstract: The invention relates to a process for distillative workup of a methanol/water mixture, in which a methanol/water mixture is added to a distillation column (1), an essentially methanol-comprising vapor stream is withdrawn at the top of the distillation column (1) and an essentially water-comprising bottom stream at the bottom of the distillation column (1), at least a portion of the essentially methanol-comprising vapor stream is compressed and the compressed vapor stream is added as heating vapor to an evaporator (11) in which at least a portion of the methanol/water mixture to be separated is evaporated.

Abstract: The present invention relates to a process for purifying crude polymethylol which comprises polymethylol of the formula (I) (HOCH2)2—C—R2 ??(I) in which each R is independently a further methylol group or an alkyl group having 1 to 22 carbon atoms or an aryl or aralkyl group having 6 to 22 carbon atoms, and also hydroxy acid of the formula (IV) in which each R is independently as defined above, which comprises performing the purification in a distillation column, the bottom of the distillation column being connected to an evaporator with a short residence time. The present invention further relates to a composition comprising polymethylol and 1 to 10 000 ppm by weight of an ester of polymethylol and of a hydroxy acid and to the use thereof.

Abstract: The present invention relates to a process for recovering components from a low boiler mixture which is obtained in the distillation of hydrogenation effluents from the preparation of polymethylols, by multistage distillation of the low boiler mixture comprising a tertiary amine, water, methanol, polymethylol of the formula (I) methylolalkanal of the formula (II) alcohol of the formula (III) and an alkanal with a methylene group in the ? position to the carbonyl group, and in which each R is independently a further methylol group or an alkyl group having 1 to 22 carbon atoms or an aryl or aralkyl group having 6 to 22 carbon atoms, a first distillation stage involving separating the low boiler mixture into a higher-boiling, predominantly water-rich fraction and into a lower-boiling aqueous organic fraction comprising the tertiary amine, and the second distillation stage involving separating the aqueous organic fraction from the first distillation stage into a predominantly amine-containing fract

Abstract: The present application relates to an improved process for preparing 6-hydroxycaproic esters from the by-product mixtures which are obtained in the oxidation of cyclohexane to cyclohexanol and cyclohexanone with oxygen or oxygen-comprising gas mixtures.

Abstract: The invention relates to a process for preparing ?-caprolactone from 6-hydroxycaproic ester in the gas phase in the presence of activated carbon as a catalyst and subsequent distillation.

Abstract: The present invention provides a process for preparing ?-caprolactone in a purity of more than 99% by cyclizing 6-hydroxycaproic esters in the liquid phase at from 150 to 400° C. and from 1 to 1020 hPa abs., and removing and condensing the compounds which are volatile under cyclization conditions, which comprises thermally treating the remaining bottom product of the cyclization in at least one further reactor, removing and condensing volatile compounds and obtaining ?-caprolactone by distillation from the condensates.

Abstract: The preparation of hydroxypivalaldehyde is effected by aldolizing isobutyraldehyde with formaldehyde and subsequently working up the resulting reaction effluent by distillation, wherein the reaction effluent is fed to a distillation column which is operated at a top pressure in the range from 0.5 to 1.5 bar and in which a two-stage condensation is provided in the top region, in which the vapors are first conducted into a partial condenser operated at a temperature in the range from 50 to 80° C., whose condensate is recycled at least partly into the distillation column, and in which the vapors uncondensed in the partial condenser are fed to a downstream condenser operated at a temperature in the range from ?40 to +30° C., whose condensate is at least partly discharged.

Abstract: The present invention provides a process for preparing ?-caprolactone in a purity above 99%, in which 6-hydroxycaproic ester comprising from 0.5 to 40% by weight of adipic diester is cyclized in the gas phase at from 150 to 450° C. in the presence of oxidic catalysts and ?-caprolactone is obtained from the cyclization product by distillation.

Abstract: The preparation of hydroxypivalaldehyde is effected by aldolizing isobutyraldehyde with formaldehyde and subsequently working up the resulting reaction effluent by distillation, wherein the reaction effluent is fed to a distillation column which is operated at a top pressure in the range from 0.5 to 1.5 bar and in which a two-stage condensation is provided in the top region, in which the vapors are first conducted into a partial condenser operated at a temperature in the range from 50 to 80° C., whose condensate is recycled at least partly into the distillation column, and in which the vapors uncondensed in the partial condenser are fed to a downstream condenser operated at a temperature in the range from ?40 to +30° C., whose condensate is at least partly discharged.

Abstract: A process for catalytically hydrogenating methylolalkanals of the general formula in which R1 and R2 are each independently a further methylol group or an alkyl group having from 1 to 22 carbon atoms or an aryl or aralkyl group having from 6 to 33 carbon atoms, in the liquid phase over a hydrogenation catalyst, which comprises setting a pH of from 7.0 to 9.0 in the hydrogenation effluent by adding at least one tertiary amine, an inorganic base or an inorganic or organic acid to the hydrogenation feed.

Abstract: The present invention provides a process for preparing 1,6-hexanediol by hydrogenating dialkyl adipates, alkyl 6-hydroxycaproates, 1,4-cyclohexanedione and 4-hydroxycyclohexan-1-one as ester mixtures comprising impurities, by a) freeing resulting the esterification mixture of excess alcohol and low boilers in a first distillation stage (alcohol removal), b) carrying out a separation of the bottom product in a second distillation stage into an ester fraction substantially free of 1,4-cyclohexanediols and a fraction comprising at least the majority of the 1,4-cyclohexanediols, c) catalytically hydrogenating the ester fraction substantially free of 1,4-cyclohexanediols (ester hydrogenation) and d) in a purifying distillation stage, obtaining 1,6-hexanediol from the hydrogenation effluent in a manner known per se, which comprises selectively hydrogenating the ester mixture before stage a) and/or before stage b) (purifying hydrogenation).