Abstract: The present invention relates to a process for preparing trioxime derivatives of the formula I in which the substituents R1 and R2 are identical or different and each is cyano, alkyl, haloalkyl or cycloalkyl, and R3 and R4 are identical or different and each is alkyl, haloalkyl, cycloalkyl, alkylcarbonyl or arylalkyl, by the following reaction steps in water without isolation of the intermediates: A) nitrosation of 1,3-diketones of the formula II ?to give monooximes of the formula III, B) oximation of III with hydroxylamine derivatives of the formula IV H2N—OR3???IV ?in which R3? is hydrogen or a group R3 to give bisoximes of the formula V, C) alkylation of V with alkylating agents or acylation of V with acylating agents to give compounds of the formula VI and D) subsequent oximation of VI with hydroxylamine to give compounds of the formula I.

Abstract: The preparation of .alpha.-carbonylphosphine oxides by oxidizing an .alpha.-hydroxyalkyl phosphine oxide with an organic hydroperoxide or of an organic peroxy acid in the presence of a compound of a Group IV to Group VIII metal in the periodic table, and novel .alpha.-hydroxybenzyl phosphine oxides. .alpha.-Carbonylphosphine oxides are used as photoinitiators for polymerizable compositions.

Abstract: The preparation of .alpha.-carbonylphosphine oxides by oxidizing an .alpha.-hydroxyalkyl phosphine oxide with an organic hydroperoxide or of an organic peroxy acid in the presence of a compound of a Group IV to Group VIII metal in the periodic table, and novel .alpha.-hydroxybenzyl phosphine oxides..alpha.-Carbonylphosphine oxides are used as photoinitiators for polymerizable compositions.

Abstract: Arenebisphosphine oxides of the general formula ##STR1## where R.sup.1 to R.sup.4 independently of one another are each hydrogen, C.sub.1 -C.sub.6 -alkyl, C.sub.1 -C.sub.6 -alkoxy, C.sub.5 -C.sub.10 -aryl, C.sub.5 -C.sub.12 -aryloxy or C.sub.7-C.sub.14 -arylalkoxy, R.sup.5 and R.sup.6 independently of one another may each be C.sub.1 -C.sub.6 -alkyl, C.sub.5 -C.sub.10 -cycloalkyl or C.sub.5 -C.sub.12 -aryl, each of which may furthermore contain one or two nitrogen or sulfur atoms in the ring system or carry one or two halogen atoms or C.sub.1 -C.sub.6 -alkyl or C.sub.1 -C.sub.6 -alkoxy groups as substituent on the ring system, or C.sub.1 -C.sub.6 -alkoxy, C.sub.3 -C.sub.8 -alkoxyalkoxy, C.sub.5 -C.sub.12 -aryloxy or C.sub.7 -C.sub.14 -arylalkoxy, or R.sup.5 and R.sup.6 together form a bridge of 2 to 10 carbon atoms, in which some of the carbon atoms may furthermore be part of an aromatic ring.

Abstract: Polyacylated aromatic compounds of formula I ##STR1## where R.sup.1 is phenyl which is unsubstituted or has inert substituents or is .alpha.-halo-C.sub.1 -C.sub.6 -alkyl, it being possible for these radicals to be identical or different;R.sup.2 is C.sub.1 -C.sub.4 -alkyl;m is 2 or 3;n is 0 to 4, it being possible for the R.sup.2 substituents to be different when n>1,with the proviso that m+n.ltoreq.6, are prepared by reacting an acylaromatic compound of the formula II ##STR2## where p is 1 or 2, with a carbonyl halide of the formula III ##STR3## where X is halogen, in an amount appropriate for the desired degree of acylation, in the presence of Fe(II), Fe(III), Zn(II), Mo(VI), W(VI) or Sn(IV) compounds.

Abstract: A process for the preparation of 2,4,6-trimethylbenzoic acid of the formula I ##STR1## in which .alpha.-chloro-2,4,6-trimethylacetophenone is reacted with an alkali hydroxide solution and chlorine in the presence of a phase-transfer catalyst at a temperature ranging from 0.degree. to 150.degree. C. and a pressure ranging from 0.01 to 50 bar, and a process for the preparation of 2,4,6-trimethylbenzoic acid I, in which .alpha.-chloro-2.4.6-trimethylacetophenone of the formula II ##STR2## is reacted with 1,3,5-trimethylbenzene and chloroacetyl chloride in the presence of a catalyst at a temperature ranging from 0.degree. to 150.degree. C. and a pressure ranging from 0.01 to 50 bar, the catalyst used being an iron oxide.