Can mono- or di-butyltin chlorides produce tributyltin chloride at elevated temperatures? Implications for applications in chemical vapour deposition

The thermolysis of the butyltin chlorides at 200–300 °C in the liquid phase has been investigated by 1H, 13C, and 119Sn NMR spectroscopy. The stabilities follow the order: Bu2SnCl2 > Bu3SnCl > BuSnCl3. Only tributyltin chloride showed any evidence of redistribution, giving dibutyltin dichloride, together with metallic tin, butane, and but-1-ene, which would be formed by decomposition of tetrabutyltin. Dibutyltin dichloride decomposed to give mainly butane with no other apparent liquid organotin compound. Butyltin trichloride gave butane, some butene, and metallic tin, and showed no evidence of forming tributyltin chloride by the redistribution reaction, which would have environmental implications for its use in the CVD coating of glass.

The decomposition and potential redistribution reaction of Bu3SnCl, Bu2SnCl2, and BuSnCl3 at 200–300 °C have been investigated by NMR spectroscopy. In particular, no toxic Bu3SnCl was formed from BuSnCl3. The principles behind the distribution reactions are discussed.Figure optionsDownload as PowerPoint slide