Abstract: The invention relates to a method of avoiding corrosion in the separation of methylamine from a product stream (10) which is obtained in the preparation of methylamines by gas-phase reaction of methanol and ammonia and comprises monomethylamine, dimethylamine, trimethylamine, ammonia and methanol as components, where ammonia is separated off by pure distillation in a first column (1), the remaining components of the product stream obtained as bottoms (12) are fed to a second column (2). Trimethylamine (14) is separated off in the second column (2) by extractive distillation with introduction of water. The further components of the product stream obtained as bottoms (15) from the second column (2) are fed to a third column (3), in which monomethylamine and dimethylamine are separated off at the top. The monomethylamine and dimethylamine are separated by distillation in a fourth column (4). To avoid corrosion alkali metal hydroxide is added to the second or third column (3).

Abstract: The invention relates to a process for recovering 3-aminomethyl-3,5,5-trimethylcyclohexylamine(isophoronediamine, IPDA) having a cis/trans isomer ratio of at least 73/27 by fractional distillation, which comprises the following steps: a) providing IPDA in a cis/trans isomer ratio of <73/27; b) feeding IPDA into the middle region of a distillation column having internals and distilling the IPDA in this distillation column at a temperature of from 5 to 300° C.

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.

Abstract: A process for continuously preparing 2-pyrrolidone by reacting gamma-butyrolactone with ammonia in the liquid phase in the presence of water, wherein the reaction is carried out at a temperature of from 275 to 300° C. and an absolute pressure of from 140 to 180 bar.

Abstract: A process for preparing polyamides comprises polymerizing starting monomers or starting oligomers in the presence of at least one compound of the formula (I) where R is a functional group R8 which bears 1-4 identical or different amide-forming groups R7, R1 is H, C1-C20-alkyl, cycloalkyl, benzyl or OR6, where R6 is H, C1-C20-alkyl, cycloalkyl or benzyl, R2, R3, R4 and R5 are independently C1-C10-alkyl, n is a natural number greater than 1, and the piperidine derivatives attached to R are identical or different with regard to the substituents, meaning R1, R2, R3, R4 and R5. The polyamides are useful for preparing filaments, fibers, films, sheetlike structures and moldings.

Abstract: Compounds of the general formula I Z—CH2—NY2−nHn  (I) where n is 0 or 1, Z is a straight-chain or branched polyalkyl radical having a number average molecular weight of from about 150 to 40,000, and Y is a radical of the formula IIa or IIb  where the radicals R, R1 and R2 independently of one another, are each hydrogen, an unsubstituted or substituted alkyl, alkenyl or alkynyl radical or an unsubstituted or substituted cycloalkyl, aryl or arylalkyl radical, which may carry one or more heteroatoms, and A is an alkyleneimine radical; or, if n is 0, one of the radicals Y may be a polyoxyalkylene radical, and processes for their preparation and fuel and lubricant compositions, and mixtures of additives, which contain the novel compounds.

Abstract: Carbonyldiimidazoles of the formulae Ia, Ib, Ic or mixtures thereof where R1 is C1-4-alkyl and R2 is hydrogen or methyl, and tert-butyl esters derived therefrom are described.

Abstract: Compounds of the general formula IZ--CH.sub.2 --NY.sub.2-n H.sub.n (I)wheren is 0 or 1,z is a straight-chain or branched polyalkyl radical having a number average molecular weight of from about 150 to 40,000, andY is a radical of the formula IIa or IIb ##STR1## where the radicals R, R.sup.1 and R.sup.2 independently of one another, are each hydrogen, an unsubstituted or substituted alkyl, alkenyl or alkynyl radical or an unsubstituted or substituted cycloalkyl, aryl or arylalkyl radical, which may carry one or more heteroatoms, andA is an alkyleneimine radical; or, ifn is 0, one of the radicals Y may be a polyoxyalkylene radical, and processes for their preparation and fuel and lubricant compositions, and mixtures of additives, which contain the novel compounds.

Abstract: Cyanoacetic esters are prepared by reacting a corresponding monochloroacetic ester with hydrogen cyanide in the presence of a base, where the base is a compound selected from the group consisting of tertiary amines, salts of carbonic acid, salts of carbonic acid monoesters, salts of carboxylic acids, amidines, guanidines and aromatic N-heterocyclic compounds.

Abstract: In the process for preparing acetylene and hydrocyanic acid by pyrolyzing acrylonitrile in a reactor, the gaseous reaction products of the pyrolysis are quenched down to less than 100.degree. C. immediately, advantageously within seconds, preferably within .ltoreq.1 s, of leaving the pyrolysis zone.

Abstract: The invention relates to a process for reducing the dimerization of piperidines of the formula I ##STR1## where R.sup.1 to R.sup.4 are C.sub.1 - to C.sub.6 -alkyl, R.sup.1 and R.sup.2 and/or R.sup.3 and R.sup.4 together are a CH.sub.2 chain having 2 to 5 carbon atoms, which comprises adding to the piperidine from 0.001 to 0.2% by weight of a reducing agent of the formula MXH.sub.4-m Y.sub.m, where M is an alkali metal, NR.sub.4, where R are identical or different C.sub.1 -C.sub.4 -alkyl groups, or an equivalent of an alkaline earth metal or an equivalent of zinc, X is boron or aluminum, Y is H or CN and m is 0 or 1. The invention also relates to a mixture of piperidines of the formula I, from 0.001 to 0.2% by weight of a reducing agent and from 1 to 1000 ppm of dimers of the piperidines of the formula I, and to the preparation of hindered amine light stabilizers therefrom.

Abstract: A process for purifying crude piperidines of the formula I ##STR1## where R.sup.1 to R.sup.4 are C.sub.1 -C.sub.6 -alkyl, or R.sup.1 and R.sup.2 and/or R.sup.3 and R.sup.4 together are a CH.sub.2 -chain of 2 to 5 carbons, which comprises, in a first step, removing high-boiling substances and, if present, water from the crude piperidines by distillation; in a second step, adding from 0.01 to 5% by weight, based on the product of the first step, as a reducing agent; and, in a third step, isolating the piperidines by distillation.

Abstract: A process for acetylating diamines having a sterically hindered amino function and a further, sterically unhindered amino function where the acetylation takes place at the sterically unhindered amino function is provided comprises reacting the diamine with ketene. A preferred diamine is 4-amino-2,2,6,6-tetramethylpiperidine (TAD).

Abstract: A process for preparing 1-acetyl-4-piperidones of the formula I ##STR1## where R.sup.1, R.sup.2, R.sup.3 and/or R.sup.4 are each a C.sub.1 - to C.sub.6 -alkyl group or R.sup.1 and R.sup.2 together or/and R.sup.3 and R.sup.4 together are an alicyclic hydrocarbon chain having from 2 to 5 carbons, comprises reacting a component comprising the corresponding nonacetylated 4-piperidone with ketene in the presence of a component comprising an acid catalyst at from 20.degree. C. to 120.degree. C.

Abstract: A description is given, as an alternative to known processes, of a process for preparing 4-amino-2,2,6,6-tetramethylpiperidine (TAD) of the formula (I) ##STR1## which comprises the steps of reacting without catalysis, in a first step, 2,2,6,6-tetramethylpiperidine-4-one(TAA) of the formula II ##STR2## with TAD to form 2,2,6,6-tetramethyl4?(2,2,6,6tetramethyl-4-piperidylidene)- amino!piperidine (imine III) of the formula III below ##STR3## and of reacting, in a further step, the imine (III) with ammonia and hydrogen in the presence of a hydrogenation catalyst to give 2 mol equivalents of TAD.

Abstract: A process for preparing 2,2,6,6-tetramethylpiperidin-4-one (TAA) is described, whereina mixture comprising acetone and/or acetone condensates and ammonia in a molar ratio of from 20:1 to 3:1at from 50.degree. to 130.degree. C.is reacted in the presence of dimethyl sulfate, the amount of dimethyl sulfate being from 0.5 to 5 mol-%, based on acetone.