Organotin Polymers and Related Materials

Hemant K. Sharma and Keith H. Pannell Department of Chemistry, University of Texas at El Paso, USA 

The amine elimination reaction between tin amides and organotin hydrides is an attractive reaction to form Sn-Sn bonds and has been used to construct linear tri- and tetrastannanes. Equation (3.8.2).  

The mechanism of this process is not clear, but it is presumed that the di-n-butylstannylene, BuaSn generated from the decomposition of (3-ethoxyethyl(di-n-butyl)stannane with lithium diisopropylamide (LDA), inserts into the tin-hydrogen bond in the chain growth step. The air-sensitive colorless oligomers are separated by reverse-phase HPLC using dichloromethane/acetonitrile solvent mixture. Short chain oligomers, n = 3,4, and 5, dominate in the mixture of oligomers, n = 1-15. 

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Butyltin compounds, monobutyltin (MBT) and dibutyltin (DBT) and tri-butyltin (TBT) are widely used for the production of biocides and polymer stabilizers. On a yearly basis, 23, 000 tons of butyltin compounds are used as additives in PVC products. This is about 40% of the world usage of organotin compounds [90]. The negative impact of butyltins on the aquatic environment is well documented and in vitro studies have also shown that they disrupt the immune response in humans [91]. Studies have shown that organotins leach out from PVC and related materials, resulting in the con-... 

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