Ciba Specialty Chemicals Corporation

Ciba-geigy Corporation

Ronald Salathe

David G Leppard

Manfred Kohler

Jean-Roch Pauquet

Hugo Illy

Helmut Linhart

Udo Quotschalla

Rudolf Schwabe

Thomas Lloyd James

Nils Hock

Molecular complex compounds comprising a mono-, bis- or trisacylphosphine oxide compound with an .alpha.-hydroxy ketone compound are suitable as photoinitiators for the photopolymerization of free-radically polymerizable compounds.

Molecular complex compounds of acylphosphine oxide and .alpha.-hydroxy

Described are compositions comprising (a) 25 to 99% of organic phosphite or phosphonite, based on the total weight of the composition, (b) an effective stabilizing amount of organic amine, and (c) an effective stabilizing amount of acid-binding metal salt, wherein said composition comprises no organic polymers or alkali metal phosphates as further components, as well as a process for stabilising organic phosphites or phosphonites against hydrolysis by addition of organic amine and acid-binding metal salt. The compositions are distinguished by their excellent stability to hydrolysis and have good storage stability even at high atmospheric humidity. The novel compositions and process products can be used with advantage as stabilisers for organic material against the harmful action of heat, oxygen and/or light.

Enhancement of the storage stability of organic phosphites and

The substituent X in the phenols of the formula: ##STR1## wherein R.sub.1 to R.sub.4 are hydrogen or unsubstituted or substituted alkyl, alkenyl or alkynyl, and X is secondary or tertiary alkyl of 3 to 9 carbon atoms, can be removed by heating said phenols in the presence of an alkali metal hydrogensulfate.

Process for the preparation of substituted phenols

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Magden, Switzerland

Ronald Salathe