Dibutyltin diacetate

In the presence of the organic siHcate, the heavy-metal salts trigger the chain extension and cross-linking reactions that lead to siHcone mbber and volatile ethanol as a byproduct. Useful metal soaps iaclude stannous octanoate [1912-83-0], ziac octanoate [557-09-5], dibutyltin dilaurate [77-58-7], and dibutyltin diacetate [1067-33-0]. The reactivity of the different salts varies considerably. Stannous octanoate effects a cure ia 0.5—2 min ziac octanoate may require 24—96 h the dibutyltin dilaurate, 10—20 min. Heat and moisture accelerate the curing rate, but to a lesser degree than ia the case of the polysulfide mbbers. 

Dibutyltin diacetate, dilaurate, and di-(2-ethylhexanoate) are used as homogeneous catalysts for room-temperature-vulcanizing (RTV) silicones. The dialkyltin compounds bring about the cross-linking of the oligomeric siloxanes, to produce flexible, silicone rubbers having a host of different uses, such as electrical insulators and dental-impression molds. Recent work has also shown (560) that various dibutyltin dicar-boxylates catalyze both the hydrolysis and gelation of ethyl silicate under neutral conditions. 

After administration of a single oral dose of dibutyltin diacetate of 22 mg/kg body weight to pregnant rats on day 8 of gestation, both dibutyltin and monobutyltin were detected in the embryos, indicating placental transfer (Noda et al., 1994). Nakamura et al. (1993) also detected dibutyltin in embryos after dosing the mother orally on days 7-17 of gestation. 

Administration of dibutyltin dichloride intraperito-neally to rats led to the formation of butyl(3-hydroxy-butyl)tm, butyl(4-hydroxybutyl)tin, and monobutyltin. The major metabolite (buty 1(3-hydroxybutyl)tin) was distributed to the kidney at a relatively high concentration compared with the other metabolites, and its concentration increased with time. Butyl(4-hydroxybutyl)tin was found in urine only. The parent compound and other metabolites were detected in the brain (Ishizaka et al., 1989). Dibutyltin diacetate was destarmylated by 14% within 90 h following a single oral dose in mice at 1.1 mg/kg body weight, with several butyltin derivatives found in the liver or faeces (Boyer, 1989). 

Dibutylstibinic acid, 3 73 Dibutyltin diacetate, 24 823 Dibutyltin dilaurate, 24 823 Dicadmium triantimonide, 4 510 Dicalcium alumino monosilicate, phase in Portland cement clinker, 5 472t Dicalcium ferrite, phase in Portland cement clinker, 5 472t Dicalcium hexaborate pentahydrate,... 

In solution, the 170 NMR spectra of tributyltin acetate and dibutyltin diacetate show a single signal in a variety of solvents over the range 200-300 K. This is interpreted to imply the existence, in solution, of a cyclic monomer in which the carboxylate groups ate anisobidentate, and are undergoing rapid intramolecular exchange 34.350... 

Asymmetric aldol reactions.1 This diamine (1) when coordinated with tin(II) triflate and dibutyltin diacetate promotes highly stereoselective aldol-type reactions between silyl enol ethers and aldehydes. 

Shen et al. [95] reported the first instance of SFC coupled to ICP-MS for tetraalkyltin speciation. The mobile phase used was C02. Tetramethyltin (TMT), tetrabutyltin (TBT), thetraphenyltin (TPT), tributyltin acetate (TBTA), and dibutyltin diacetate (DBTDA) were all resolved. C02 was also used as the auxiliary gas flow for ICP-MS. The Sn signal was optimized by adjusting the C02 flow and the rf forward power. The compounds were found to interact poorly with the stationary phase thus only TBT and TPT could be separated. No organic modifiers were added, however. Further organotin speciation studies by the same group... 

Marvel and Horning (6) suggested an allyl (zipper) mechanism. More is known about the mechanism of PVC stabilization with tin compounds as Kenyon (5) has shown. In this case, it could be proved with Cu-labelled dibutyltin diacetate, that only the butyl groups react with the radicals, and the rest adds on the HC1. 

An amorphous tin oxide film was formed by decomposing dibutyltin diacetate via an oxygen plasma. Preliminary measurements indicated that the electrical resistivity of the film near room temperature was greater than 107 ohm-cm. Comparing the infrared spectra of the film and Sn02,... 

Hostettler and Cox [141] reported relative reaction rates of phenyl isocyanate with ra-butanol, water, and diphenyl urea by various catalysts. Taking the rate of phenyl isocyanate with -butanol as 1, relative rates catalyzed by N-methylmorpholine (II), triethylamine, tetramethyl-1,3—butanediamine, triethylenediamine, tributyltin acetate, and dibutyltin diacetate are 40, 86, 260, 1200, 80,000, and 600,000, respectively. The relative rate with water when uncatalyzed is 1.1, while the relative rates catalyzed by N-methylmorpholine (II),... 

The second type of composition is exemplified by a wide variety of acrylate- or methacrylate-ester derivatives of conventional ink vehicles combined with a photoinitiator 1. The reaction product of tung oil fatty acids, glycidyl methacrylate, -benzoquinone, and 2-methyl-imidazole mixed with tung oil and treated with tolylene diisocyanate, combined with benzoin methyl ether (26) 2. Glycerol-linseed oil-isophthalic acid alkyd reacted with isocyanate-containing prepolymer (formed by reaction of tolylene diisocyanate, -henzoquinone, 2-hydroxypropyl acrylate in ethyl acetate solution) using dibutyltin diacetate catalyst, combined with tung oil, synthetic varnish, and benzoin methyl ether (27) 3. Epoxidized... 

In addition to tin compounds such as dibutyltin dilaurate and dibutyltin diacetate, various other metal compounds have been claimed to be effective deblocking catalysts such as zinc naphthenate (70), lead naphthenate, bismuth salts, and titanates (71), and Ca, Mg, Sr, or Ba salts of hexanoic, octanoic, naphthenic, or linolenic acid (72) and metal acetyl acetonates (73). Also combinations of organotin compounds and quaternary ammonium salts have been claimed to have a synergistic effect in lowering the deblocking temperature (74). 

An even simpler system composed of dibutyltin diacetate and dibutyltin dichloride was examined by both 13C NMR and low-temperature XH NMR because of the report that dibutylchlorotin acetate formed immediately when the reagents were mixed in carbon tetrachloride (16). The 13C spectra of the pure diacetate and the mixed system were obtained using conditions suitable for quantitative analysis. In deuterochloroform, at 30 °C, over a wide range of concentrations, no evidence could be found for the presence of the excess component or the exclusive formation of dibutylchlorotin acetate. The 1H NMR spectra gave similar results and the spectra were unchanged between 50° and — 50° C. 

Organic tin compounds Dialkyltin compounds - especially dimethyl-tin and diethyltin dichloride - are dermal irritants, but several of them (e.g., dibutyltin diacetate, dilaurate, maleate, oxide) do not cause such irritation (Lyle 1958). Tributyl and trimethyltin compounds are not allergic dermal and conjunctival irritants, but are responsible for the acute burns that appear several hours after the dermal contact. 

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