Albright & Wilson Limited

Trevor E Jones

John Desmond Collins

Robert E Talbot

Stephen Crelling

Chlorine dioxide is used to stabilize hydrogen peroxide in bleach liquor at alkaline pH. This is thought to be aided by the destruction of enzymes (especially catalase) produced by bacteria. The method is useful for the reprocessing of pulps, especially when a de-inking stage is involved.

Method of peroxide bleaching of pulp using a peroxide decomposing

Organotin compounds comprising at least 50% and often at least 90% tetraorganotin compound and the remainder triorganotin halide, which are suitable for conversion to organotin precursors of stabilizers for polymers or fungicides, are made by reacting an alkyl or alkenyl halide with a mixture of tin and zinc (or alloy thereof) with an atomic ratio of at least 0.5:1 zinc to tin, in a liquid comprising an 'onium salt, to produce the organotin compound at least some of which is in the liquid.

Process for preparing organotin compounds

Tricycloalkyltin halides, e.g. tricyclohexyltin chloride, which is an intermediate for making the biocide tricyclohexyl tin hydroxide, are made by adding a solution of the cyclo alkyl magnesium halide in an ether to a solution of stannic halide in a liquid diluent, the weight percentage of stannic halide to diluent being less than 25%.

Process for preparing organotin halides

Tetraalkyltin compounds substantially free from tin, tin alkyl and di alkyl contaminants are prepared by reacting an alkyl halide of 1 - 4 carbon atoms with tin in the presence of an 'onium salt e.g. a quaternary ammonium halide and at least 0.5 g atom of zinc per g atom of tin, and collecting a vapor phase effluent comprising the tetraalkyltin. The tetraalkyltin can be disproportionated with stannic chloride to give alkyltin chlorides, intermediates for making stabilizers for polymers and biocides.

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Halesowen, United Kingdom

Trevor E Jones