Tributyltin hydroxide

For binder preparation, dilute hydrochloric or acetic acids are preferred, because these faciUtate formation of stable silanol condensation products. When more complete condensation or gelation is preferred, a wider range of catalysts, including moderately basic ones, is employed. These materials, which are often called hardeners or accelerators, include aqueous ammonia, ammonium carbonate, triethanolamine, calcium hydroxide, magnesium oxide, dicyclohexylamine, alcohoHc ammonium acetate, and tributyltin oxide (11,12). 

TBTO is a colorless liquid of low water solubility and low polarity. Its water solubility varies between <1.0 and >100 mg/L, depending on the pH, temperature, and presence of other anions. These other anions determine the speciation of tributyltin in natural waters. Thus, in sea water, TBT exists largely as hydroxide, chloride, and carbonate, the structures of which are given in Figure 8.5. At pH values below 7.0, the predominant forms are the chloride and the protonated hydroxide at pH8 they are the chloride, hydroxide, and carbonate and at pH values above 10 they are the hydroxide and the carbonate (EHC 116). 

Wronski [55] described a method to separate and resolve penicillamine from physiological fluids. To urine (100 mL) was added 60 g of (NH4)2S04, the solution was filtered, mixed with 2 g of Na2S03, and 1 mL of 0.1 M EDTA in 20% triethanolamine, and shaken with 5-20 mL of 0.01-0.06 M tributyltin hydroxide in octane for 5 min. A portion (5-8 mL) of the organic phase was shaken with 0.2 mL of HC1 in 20% glycerol solution. A portion of the aqueous phase (5-10 pL per cm of the strip width) was applied to cellulose gel, and electrophoretic separation was performed by the technique described previously. The thiol spots were visualized with o-hydroxymercuri benzoic acid-dithiofluorescein and densitometry with a 588-nm filter. 

Laughlin et al. [122] analysed chloroform extracts of tributyltin dissolved in seawater using nuclear magnetic resonance spectroscopy. It was shown that an equilibrium mixture occurs which contains tributyltin chloride, tributyl tin hydroxide, the aquo complex, and a tributyltin carbonate species. Fluorometry has been used to determine triphenyltin compounds in seawater [123]. Triph-enyltin compounds in water at concentrations of 0.004-2 pmg/1 are readily extracted into toluene and can be determined by spectrofluorometric measurements of the triphenyltin-3-hydroxyflavone complex. 

Tributyltin carboxylates act like weak acids, and can be titrated in hexane-ethanol (1 1) medium against alkali. Tributyltin chloride (TBTC1) is also a weak acid, and gives a sharp end point when similarly titrated against sodium hydroxide. TBTCl gives an instantaneous precipitate with silver nitrate in aqueous alcoholic medium. 

There is also no conclusive evidence that inorganic tin compounds have carcinogenic properties. However, there are data which indicate that organotin compounds (bis(tributyltin)oxide and triphenyltin hydroxide) may be tumorigenic at low levels of tin. Bis(tributyltin)oxide (2.5 mg/kg/day) and triphenyl tin hydroxide (0.3-6.2 mg/kg/day) were associated with pituitary adenomas in rats of both sexes with exposures of 104-106 weeks. When triphenyltin hydroxide was administered, the pituitary adenomas were present only in the females and contributed to decreased longevity. 

In the studies of long-term exposure of rats to both triphenyltin hydroxide and bis(tributyltin)oxide, most of the tumors were found in endocrine glands. In addition to the pituitary adenomas associated with bis(tributyltin)oxide and triphenyltin hydroxide, there was also an increased incidence of pheochromocytomas of the adrenal gland, parathyroid carcinomas and pancreatic adenocarcinomas in animals from at least one sex. Triphenyltin hydroxide was associated with an increased incidence of testicular Leydig cell tumors in male rats at the highest dose. Hepatic tumors were found in male and female mice following 80 weeks of triphenyltin hydroxide administration. 

Benzoyl chloride Tributyltin chloride Boron trifluoride Sodium hydride Sodium hydroxide Sodium bisulfate Diazomethane... 

Trialkyltin compounds have been shown to be effective agriculturally. Tributyltin oxide (III) has insecticidal and fungicidal activity, but generally has not been useful for plant protection due to phytotoxicity and volatility problems. Tricyclohexyltin hydroxide (TCTH, IV) has been an extremely effective acaricide.(3) Developed under the trade name Plictran, this compound was one of the first commercial acaricides. Another trialkyltin compound under development is hexakis (jS > j3 -dimethylphenylethyl)distannoxane (Vendex, V), which is also an effective acaricide. 

One Te-C bond in a diorgano tellurium can be cleaved by alkali metals, organic lithium compounds, sodium hydroxide, lithium aluminum hydride, sodium borohydride, Grignard reagents, tributyltin hydride, sulfuric acid, sodium sulfide, sulfuryl chloride, hydrogen bromide, bromine, or iodine. The Te-C bond can also be broken thermally or through photostimulation. 

Tributylstannyl ethers are prepared in the same manner by reaction of alcohols with hexabutyldistannoxane (more commonly known as bistribu-tyltin oxide). Holzapfel et al. noted that the reaction in benzene requires only 0.5 molar equivalents of bistributyltin oxide to go to completion but takes 16 h at reflux (Fig. 2). This is probably because the tin-containing by-product of the first half of the reaction, tributyltin hydroxide, reacts much more slowly than the initial reagent.18... 

These polymers underwent radical allylation [13] using allyltributyltin to give adducts 94 and 95, and reduction with tributyltin hydride to give the products 96 and 97 (Scheme 20). All products were obtained in high yield as white crystalline materials which could be easily separated from tin byproducts. The products were released from the polymer support by hydrolysis with lithium hydroxide. 

The triorganotin species have been used as industrial biocides for over 30 years [117, 118]. Examples are triphenyltin hydroxide (structure 5) for fungal diseases on celery, rice, sugar beets, and coffee tricyclohexylstannyl-1,2,4-triazole (structure 6) as an acaricide for apple, pear, and citrus fruit trees bistributyltin oxide (structure 7) as a wood preservative and tributyltin-methylacrylate monomers (structure 8) polymerized with other acrylates to yield a marine antifoulant polymer that prevents the build of up barnacles, algae, and other marine animals on ships. 

Traces of hydrogen cyanide have been separated conveniently by the microdiffusion method (also referred to as isothermal distillation) [7]. Cyanide has been preconcentrated from water by extraction with tributyltin hydroxide in trichloroethylene [8]. 

Reductive radical elimination (Barton deoxygenation) of the 3, 4 -xanthate derivative of neamine (70) has been used to prepare the key intermediate 71 (compounds 70, 71) for the synthesis of the 3, 4 -dideoxyneamine analog gentamine Cia [52]. In this synthesis, a precursor possessing free hydroxyl groups at positions 3 and 4 was treated with a mixture of carbon disulfide, aqueous sodium hydroxide, and methyl iodide in DMSO to afford compound 70. Subsequent reduction of 70 with tributyltin hydride furnished the olefin 71, which affer cafalyfic hydrogenation and deprofecfion was converted to gentamine Cia. 

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