Tributyltin compounds, applications

Butyltin compounds, in contrast, are produced only anthropogenically. Besides the applications covered in this CICAD, there exist other applications of butyltin compounds that may represent a significant source of these substances in the environment. In particular, the use of tributyltin compounds in antifouling coatings represents a significant source of these substances in the marine and freshwater environments. Hence, many of the measured concentrations reported will relate predominantly to this use. 

Triphenyl- and tributyltin compounds have strongly biocidal properties and are employed in some agricultural fungicides and wood preservatives42. Other possible applications include disinfectants for use in hospitals and for the eradication of snails that transmit bilharzia. However, these compounds are potentially hazardous because of the ease with which they inhibit oxidative phosphorylation in man. Oral administration of diethyltin diiodide as a treatment for boils led to many deaths43. ... 

The Stille protocol is now well established, and finds many uses in preparative chemistry. Especially, application to the synthesis of bioactive substances and functional materials is noteworthy. The choice of catalyst and solvent, however, is still remained veiled. If the reaction to be attempted is not well documented, one should first try to find the most suitable reaction conditions. Organotin compounds can be extremely toxic, and tributyltin compounds are recently suspected to be endocrine disrupters. The presence of even traces of organotin contaminants in organic products must be avoided, as far as possible. In spite of these problems, the Stille protocol will continue to be a favorite method for car-bon-carbon-bond formation, owing to the mildness of the reaction conditions and the functional tolerability of both substrates and reagents. 

Tributyltin compounds are significantly more toxic to marine organisms than to rats or (presumably) humans. For this reason, they have been used in marine paints as antifoulants for many years. Their economic benefit in such applications has been estimated at 3 billion annually, much of which is attributable to savings in fuel with a resultant decrease in engine emissions to the environment. The small amounts of tri-... 

An obvious direct consequence of the wide range of industrial applications of tin chemicals is that a proportion of these compounds will ultimately be found in environmental media. Tributyltin compounds are directly introduced into aquatic systems via leaching from antifouling paints. Even... 

TBSnA is preferably produced in situ. Also with a view to the environmental risk potential involved in the recovery of tributyltin compounds the commercial-scale application should be left in the hands of specialized producers. 

Butyl- and phenyltin compounds, particularly the trialkylated forms are very toxic to marine life. The antifouling paints, mainly tributyltin (TBT) but also triphenyltin (TPhT) caused and continue to cause substantial damage because of their slow biodegradation and their accumulation in the biota, notwithstanding a substantial reduction in application through multi-national regulation). 

In a 90-day repeated dose dermal study, rabbits developed skin irritation at each of three levels tested (14, 27, and 68 mg/kg/day tributyltin fluoride) (Sheldon 1975). Deaths occurred in 7 of 10 rabbits at a level of 68 mg/kg, but surviving animals eventually returned to normal a few days after compound was withdrawn. A level of 14 mg/kg (65 applications) was stated by the authors to be a NOAEL despite local irritation at the application sites. In view of the exaggerated daily contact with the rabbit skin, this value seems reasonable since such high levels of daily exposure would not be the case in humans. However, a detailed report of this study was not available for review. 

Organo-tin compounds have been used as catalysts, stabilisers for plastics and biocides. Tributyltin (TBT) species are very effective biocides, and have been incorporated as active agents in antifouling compounds for marine applications. However, TBT has seriously affected other marine organisms such as oysters, crabs and fish even at parts per billion and lower concentrations in water. Consequendy, the determinations of low levels of TBT and dibutyl tin (DBT), its less toxic primary degradation product in water and in biological materials, are very important. 

The synthetic application of free-radical reactions has increased dramatically over the past twenty years. Nowadays, radical reactions can often be found driving the key steps of multistep chemical syntheses oriented towards the construction of complex natural products or other synthetic targets. The majority of radical reactions of interest to synthetic chemists are chain processes. Tributyltin hydride is by far the most commonly used reagent for the rednction of fnnctional groups and formation of C—C bonds either inter- or intramolecnlarly (cyclization) " , although, as already alluded to, there are several problems associated with organotin compounds. The main drawback consists of the incomplete removal of allegedly toxic tin by-products from the final material ... 

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