Abstract:
A process for preparing toluene derivatives of the formula I where R1, R2 and R3 are, independently of one another, hydrogen, alkyl radicals, hydroxyl groups and/or alkoxy groups, comprises reacting the corresponding benzoic acids, benzoic esters or benzoic anhydrides with hydrogen in the presence of a catalyst.
Abstract:
In a process for preparing alcohols by catalytic hydrogenation of carbonyl compounds over a catalyst comprising rhenium on activated carbon, the catalyst used comprises rhenium (calculated as metal) in a weight ratio to the activated carbon of from 0.0001 to 0.5, platinum (calculated as metal) in a weight ratio to the activated carbon of from 0.0001 to 0.5 and, if appropriate, at least one further metal selected from among Zn, Cu, Ag, Au, Ni, Fe, Ru, Mn, Cr, Mo, W and V in a weight ratio to the activated carbon of from 0 to 0.25, and the activated carbon has been nonoxidatively pretreated It is also possible to prepare ethers and lactones if the hydrogen pressure is not more than 25 bar. In this case, the activated carbon in the catalyst may also have been nonoxidatively pretreated.
Abstract:
A process for preparing toluene derivatives of the formula I, where R1, R2 and R3 independently of one another are hydrogen, halogen, C1-C6-alkyl, hydroxyl or C1-C6-alkoxy, by hydrogenating benzaldehydes and/or benzyl alcohols of the formula II, with hydrogen in the presence of a catalyst, which is described in more detail in the description.
Abstract:
Unsubstituted or alkyl-substituted THF is obtained by catalytic hydrogenation in the gas phase of C4-dicarboxylic acids and/or their derivatives using a catalyst comprising 20% by weight, preferably >30% by weight, in particular from 35 to 90% by weight, of an oxidic support having acid centers, at a hot spot temperature of from 240 to 310° C., preferably from 240 to 280° C., and a WHSV over the catalyst of from 0.01 to 1.0, preferably from 0.02 to 1, in particular from 0.05 to 0.5, kg of starting material/l of catalyst x hour.
Abstract:
A process for the single-stage preparation of polytetrahydrofuran and/or tetrahydrofuran copolymers having a mean molecular weight of from 650 to 5000 dalton by polymerization of tetrahydrofuran over a heterogeneous acid catalyst in the presence of at least one telogen and/or comonomer selected from the group consisting of alpha,omega-diols, water, polytetrahydrofuran having a molecular weight of from 200 to 700 dalton and cyclic ethers comprises a) separating off the catalyst and/or downstream products of the catalyst suspended and/or dissolved in the output from the polymerization, b) fractionating the resulting catalyst-free output from the polymerization in at least one distillation step to give a distillation residue comprising the polymerization product and at least one tetrahydrofuran fraction and returning at least part of the tetrahydrofuran fraction to the polymerization and c) separating low molecular weight polytetrahydrofuran and/or tetrahydrofuran copolymers having a mean molecular weight of from 200 to 700 dalton from the distillation residue from work-up step b) and isolating polytetrahydrofuran and/or tetrahydrofuran copolymers having a mean molecular weight of from 650 to 5000 dalton.
Abstract:
A process is provided for the preparation of cyclic lactams of formula (II): in which n and m can each have the values 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9 and the sum of n+m is at least 3, preferably at least 4, and R1 and R2 are C1-C6-alkyl, C5-C7-cycloalkyl or C6-C12-aryl groups, by reacting a compound (I) of the formula in which R1, R2, m and n are as defined above and R are [sic] nitrile, carboxamide and carboxylic acid groups, with steam in the gas phase.
Abstract:
A process is provided for the preparation of caprolactam from a compound of formula (I): NC—(CH2)5—CO—R (I) in which R is a carboxamide, carboxylic acid or carboxylic acid ester group, wherein a) a compound (I) or a mixture of such compounds, in the presence of ammonia and optionally a liquid diluent (VI), is hydrogenated with hydrogen in the presence of a catalyst (II) to give a mixture (III), b) the hydrogen and the catalyst (II) are separated from the mixture (III) to give a mixture (IV), and c) the mixture (IV), optionally in the presence of a liquid diluent (VII), is converted to caprolactam in the presence of a catalyst (V).
Abstract:
A process for the coproduction of 6-aminocapronitrile (ACN) and hexamethylenediamine (HMD) by treatment of adiponitrile (ADN) with hydrogen in the presence of a nickel-containing catalyst at temperatures not below room temperature and elevated hydrogen partial pressure in the presence or absence of a solvent comprises, after the conversion based on ADN and/or the selectivity based on ACN has or have dropped below a defined value (a) interrupting the treatment of ADN with hydrogen by stopping the feed of ADN and of the solvent, if used, (b) treating the catalyst at from 150.degree. to 400.degree. C. with hydrogen using a hydrogen pressure within the range from 0.1 to 30 MPa and a treatment time within the range from 2 to 48 h, and (c) then continuing the hydrogenation of ADN with the treated catalyst of stage (b).
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:
Process for the continuous preparation of N-methyl-2-pyrrolidone (NMP) by reacting gamma-butyrolactone (GBL) with monomethylamine (MMA) in the liquid phase, wherein GBL and MMA are used in a molar ratio of from 1:1.08 to 1:2 and the reaction is carried out at from 320 to 380° C. and an absolute pressure of from 70 to 120 bar.