Abstract: The present invention relates to a mixture comprising itaconic acid or an itaconic acid derivative and a primary amine of the formula (I) R—NH2??(I) where the molar ratio of primary amine to itaconic acid or the itaconic acid derivative is in the range from 0.5:1 to 20:1, wherein the mixture comprises 50 mole percent or less of 4-carboxypyrrolidones of the formula (II), derivatives of the 4-carboxypyrrolidones of the formula (II) and 4-carbamidopyrrolidones of the formula (III) based on the itaconic acid used or the itaconic acid derivative used and in which R is a linear or branched saturated aliphatic radical having 1 to 24 carbon atoms or a saturated cycloaliphatic radical having 3 to 24 carbon atoms. The invention further provides for the use of the inventive mixtures for preparing 1,3-alkylmethylpyrrolidones and/or 1,4-alkylmethylpyrrolidones, and also a process for preparing 1,3-alkylmethylpyrrolidones and/or 1,4-alkylmethylpyrrolidones.

Abstract: The present invention relates to substituted N-(cyclo)alkylpyrrolidones as solvents for use in processes for preparing polyurethane dispersions.

Abstract: The present invention provides a process for preparing 2-methyltetrahydrofuran by one-stage hydrogenation of furfural with a hydrogen-comprising gas in the presence of a structured bed of at least one copper catalyst and at least one catalyst which comprises at least one noble metal from groups 8, 9 and/or 10 of the periodic table of the elements applied on a support material.

Abstract: The present invention relates to substituted N-(cyclo)alkylpyrrolidones as solvents for use in processes for preparing polyurethane dispersions.

Abstract: The present invention provides a process for changing the given mean molecular weight Mn in the continuous preparation of polytetrahydrofuran or tetrahydrofuran copolymers, the mono- or diesters of polytetrahydrofuran or of tetrahydrofuran copolymers by polymerizing tetrahydrofuran in the presence of a telogen and/or of a comonomer over an acidic catalyst, wherein a) the molar ratio of telogen to tetrahydrofuran or to tetrahydrofuran and comonomer is changed, b) then the mean molecular weight of at least one sample is determined, c) until the mean molecular weight thus determined differs from the molecular weight to be achieved by the change, the already formed polytetrahydrofuran or the tetrahydrofuran copolymers, the mono- or diesters of polytetrahydrofuran or tetrahydrofuran copolymer is at least partly depolymerized over an acidic catalyst and d) the tetrahydrofuran recovered by depolymerization is recycled at least partly into the polymerization.

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 mixture comprising itaconic acid or an itaconic acid derivative and a primary amine of the formula (I) R—NH2??(I) where the molar ratio of primary amine to itaconic acid or the itaconic acid derivative is in the range from 0.5:1 to 20:1, wherein the mixture comprises 50 mole percent or less of 4-carboxypyrrolidones of the formula (II), derivatives of the 4-carboxypyrrolidones of the formula (II) and 4-carbamidopyrrolidones of the formula (III) based on the itaconic acid used or the itaconic acid derivative used and in which R is a linear or branched saturated aliphatic radical having 1 to 24 carbon atoms or a saturated cycloaliphatic radical having 3 to 24 carbon atoms. The invention further provides for the use of the inventive mixtures for preparing 1,3-alkylmethylpyrrolidones and/or 1,4-alkylmethylpyrrolidones, and also a process for preparing 1,3-alkylmethylpyrrolidones and/or 1,4-alkylmethylpyrrolidones.

Abstract: The present invention relates to a process for preparing polytetrahydrofuran or tetrahydrofuran copolymers by polymerization of tetrahydrofuran in the presence of a telogen and/or a comonomer over a fixed bed of an acid catalyst, in which the temperature of the polymerization mixture increases in the direction of flow through the catalyst bed.

Abstract: The invention relates to an apparatus for separating a liquid substance mixture by distillation, a method for producing a tetrahydrofuran homopolymer and copolymer in which the oligomers in a liquid starting mixture containing oligomers are separated by distillation in such an apparatus, tetrahydrofuran homopolymers and copolymers which can be obtained using said method and have a narrow distribution of the relative molar mass, and the use thereof.

Abstract: The present invention provides a process for depolymerizing mixtures comprising mono- and/or diesters of polytetrahydrofuran in the presence of an acidic catalyst and of a C1- to C3-alcohol at temperatures of from 80 to 200° C. and a pressure of from 0.05 to 0.5 MPa, where the molar ratio of the C1- to C3-alcohol relative to the carboxyl groups present in the mixture is greater than 1.

Abstract: The present invention provides a catalyst comprising a mixture of at least one acid-activated sheet silicate with a transition metal oxide of groups 8 and/or 9 of the Periodic Table of the Elements and also a process for preparing polytetrahydrofuran, polytetrahydrofuran copolymers, diesters or monoesters of these polymers, in which tetrahydrofuran is polymerized in the presence of at least one telogen and/or comonomer over such a catalyst.

Abstract: The present invention provides a process for depolymerizing mixtures comprising mono- and/or diesters of polytetrahydrofuran in the presence of an acidic catalyst and of a C1- to C3-alcohol at temperatures of from 80 to 200° C. and a pressure of from 0.05 to 0.5 MPa, where the molar ratio of the C1- to C3-alcohol relative to the carboxyl groups present in the mixture is greater than 1.

Abstract: A process for preparing an N-alkyllactam with improved color quality, wherein from 0.01 to 10% by weight of a C1-10-alcohol or a compound which releases from 0.01 to 10% by weight of a C1-10-alcohol is added to the N-alkyllactam. A mixture comprising at least 99.0% by weight of an N-alkyllactam and in the range from 100 to 5000 ppm by weight of a C1-10-alcohol or of an acetal, aminal or of an Orthoester which releases in the range from 100 to 5000 ppm by weight of a C1-10-alcohol.

Abstract: A process for preparing an N-alkyllactam with improved color quality, wherein from 0.01 to 10% by weight of a C1-10-alcohol or a compound which releases from 0.01 to 10% by weight of a C1-10-alcohol is added to the N-alkyllactam. A mixture comprising at least 99.0% by weight of an N-alkyllactam and in the range from 100 to 5000 ppm by weight of a C1-10-alcohol or of an acetal, aminal or of an orthoester which releases in the range from 100 to 5000 ppm by weight of a C1-10-alcohol.

Abstract: The present invention provides a process for changing the given mean molecular weight Mn in the continuous preparation of polytetrahydrofuran or tetrahydrofuran copolymers, the mono- or diesters of polytetrahydrofuran or of tetrahydrofuran copolymers by polymerizing tetrahydrofuran in the presence of a telogen and/or of a comonomer over an acidic catalyst, wherein a) the molar ratio of telogen to tetrahydrofuran or to tetrahydrofuran and comonomer is changed, b) then the mean molecular weight of at least one sample is determined, c) until the mean molecular weight thus determined differs from the molecular weight to be achieved by the change, the already formed polytetrahydrofuran or the tetrahydrofuran copolymers, the mono- or diesters of polytetrahydrofuran or tetrahydrofuran copolymer is at least partly depolymerized over an acidic catalyst and d) the tetrahydrofuran recovered by depolymerization is recycled at least partly into the polymerization.

Abstract: The present invention provides a process for preparing 2-methyltetrahydrofuran by one-stage hydrogenation of furfural with a hydrogen-comprising gas in the presence of a supported catalyst which comprises at least one noble metal from groups 8, 9 and/or 10 of the periodic table of the elements.

Abstract: The present invention provides a process for preparing 2-methyltetrahydrofuran by one-stage hydrogenation of furfural with a hydrogen-comprising gas in the presence of a structured bed of at least one copper catalyst and at least one catalyst which comprises at least one noble metal from groups 8, 9 and/or 10 of the periodic table of the elements applied on a support material.

Abstract: The present invention relates to a process for preparing polytetrahydrofuran or tetrahydrofuran copolymers by polymerization of tetrahydrofuran in the presence of a telogen and/or a comonomer over a fixed bed of an acid catalyst, in which the temperature of the polymerization mixture increases in the direction of flow through the catalyst bed.

Abstract: A process for preparing an N-alkyllactam with improved color quality, wherein from 0.01 to 10% by weight of a C1-10-alcohol or a compound which releases from 0.01 to 10% by weight of a C1-10-alcohol is added to the N-alkyllactam. A mixture comprising at least 99.0% by weight of an N-alkyllactam and in the range from 100 to 5000 ppm by weight of a C1-10-alcohol or of an acetal, aminal or of an orthoester which releases in the range from 100 to 5000 ppm by weight of a C1-10-alcohol.

Abstract: The present invention provides a catalyst comprising a mixture of at least one acid-activated sheet silicate with a transition metal oxide of groups 8 and/or 9 of the Periodic Table of the Elements and also a process for preparing polytetrahydrofuran, polytetrahy-drofuran copolymers, diesters or monoesters of these polymers, in which tetrahydrofuran is polymerized in the presence of at least one telogen and/or comonomer over such a catalyst.