摘要:
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.
摘要:
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.
摘要:
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.