SYNTHESE DIRECTE DE DICHLORURE DE DIALCOYLETAIN

1,222,642. Dialkyl tin dichlorides. CARLISLE CHEMICAL WORKS Inc. 3 Jan., 1969 [25 Jan., 1968], No. 574/69. Heading C2J. (R1) 2 SnCl 2 , where the groups R1, which may be the same or different, are alkyl groups having 1 to 4 carbon atoms, is prepared by reacting tin with at least one alkyl chloride R1Cl in the presence of a quaternary ammonium or phosphonium iodide, or a tertiary ammonium or phosphonium diiodide (the ammonium compounds containing at least 6 carbon atoms), separating the product and recycling the residue, which contains other tin compounds and catalyst, to form more (R1) 2 SnCl 2 by reacting R1Cl and tin in its presence. The catalyst may be formed in situ, for example, by reacting an alkyl iodide with a secondary or tertiary phosphine. Preferably the recycling is performed at least 4 times.