Abstract: Pentaerythrityl tetrakis-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] is prepared by transesterifying a lower alkyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate with pentaerythritol in the presence of a basic catalyst, without addition of an inert solvent and in a 15 to 50% excess of lower alkyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate over the stoichiometric amount of 4 moles per 1 mole of pentaerythritol.An extremely good yield of pure crystalline product is obtained by the process of the invention.

Abstract: The invention relates to N-acyl-o-phenylenediamines of the formula ##STR1## wherein A is a colorless carbocyclic or heterocyclic aromatic radical and each of R.sub.1 and R.sub.2 independently is an alkyl, alkenyl or phenyl radical which is unsubstituted or substituted by non-chromophoric groups, but only one of R.sub.1 and R.sub.2 can be phenyl, and the ring B can also be substituted by non-chromophoric groups. The invention also relates to processes for the manufacture of these compounds, their use for whitening man-made organic material their conversion into benzimidazolium compounds as well as stable, concentrated aqueous solutions of such compounds, processes for their manufacture and their use for whitening manmade organic material.

Abstract: The invention relates to N-acyl-o-phenylenediamines of the formula ##STR1## wherein A is a colorless carbocyclic or heterocyclic aromatic radical and each of R.sub.1 and R.sub.2 independently is an alkyl, alkenyl or phenyl radical which is unsubstituted or substituted by non-chromophoric groups, but only one of R.sub.1 and R.sub.2 can be phenyl, and the ring B can also be substituted by non-chromophoric groups. The invention also relates to processes for the manufacture of these compounds, their use for whitening man-made organic material, their conversion into benzimidazolium compounds as well as stable, concentrated aqueous solutions of such compounds, processes for their manufacture and their use for whitening man-made organic material.