Abstract: 4-Acylaminopiperidine N-oxides IaA.sup.1 B.sup.1 (Ia)where A.sup.1 is hydrogen or an organic radical and B.sup.1 is a radical IIa ##STR1## where R.sup.1 -R.sup.4 are each C.sub.1 -C.sub.4 -alkyl and R.sup.1 and R.sup.2, on the one hand, and R.sup.3 and R.sup.4, on the other hand, may furthermore be bonded to form a 5-membered or 6-membered ring,R.sup.5 is H or C.sub.1 14 C.sub.4 -alkyl andR.sup.6 is H or C.sub.1 -C.sub.18 -alkyl,are used for stabilizing organic materials against the harmful effect of free radicals, particularly in the distillation of monomers which undergo free radical polymerization, especially styrene.

Abstract: A process for the preparation of iron-, potassium- and cerium-containing catalysts for the dehydrogenation of hydrocarbons from the same spent catalysts (regeneration) by grinding and, if necessary, purifying the spent material, restoring the original activity by adjusting the composition and restoring the external shape comprises adding to the ground material an effective amount of potassium and such an amount of cerium that the total amount of cerium is greater than the amount originally present.

Abstract: A process for the continuous preparation of ethylbenzene in a heterogeneous-phase reaction by alkylating benzene with ethylene in the presence of a catalyst based on a complex organic aluminum chloride compound and a co-catalyst at an elevated temperature and elevated pressure, with a residence time of from 5 to 60 minutes in one or more reaction zones, the reaction mixture, after completion of the reaction, being fed into a pressure vessel and vigorously mixed therein for from 20 to 60 minutes at from 120.degree. to 160.degree. C.