Monobutyltins

The oxide monobutyltin oxide [51590-67-1J, is a sesquioxide, C H SnO from which it is difficult to remove the last traces of water. It is an infusible, insoluble, amorphous white powder that forms when butyltin trichloride is hydrolyzed with base. The partially dehydrated material, butylstaimoic acid [2273-43-0] is slightly acidic and forms alkaH metal salts. These salts, ie, alkaH metal alkylstaimonates, form when excess alkaH is used to hydrolyze the organotin trichloride ... 

Certain monobutyltin compounds have recently been introduced 561) as esterification catalysts, e.g., in the reaction of phthalic anhydride with octanol to produce dioctyl phthalate. 

M and T Chemicals Inc., Technical Data Sheet "FASCAT 4101 Monobutyltin Esterification Catalyst. Rahway, New Jersey, 1977. 

Neurotoxicity is the major end-point for the methyl-tins, with a NOAEL of approximately 0.6 mg/kg body weight based on neuropathology for dimethyltin limited data for monomethyltin preclude the derivation of a NOAEL. No neurotoxicity was found with dibutyltin or mono- and dioctyltins no information is available for monobutyltin. 

Tributyltin is well established as an aromatase inhibitor, and dibutyltin appears to have some potency also (exact characterization of the endocrine disrupting capacity of dibutyltin alone is difficult because of the presence of tributyltin as an impurity). Monobutyltin and mono- and dioctyltins have no aromatase inhibiting capacity in in vitro tests. No data are available for this end-point for the methyltins. 

Reliable lifetime TDI values cannot be derived, since long-term studies at the appropriate doses and in the appropriate species are not available. Medium-term exposure TDIs for the estimation of risk were estimated (as the chlorides) as 0.0012 mg/kg body weight for monomethyltin and dimethyltin based on neurotoxicity, 0.003 mg/kg body weight for dibutyltin based on immunotoxicity, and 0.002 mg/kg body weight for dioctyltin, also based on immunotoxicity. No reliable TDI could be derived for monobutyltin or monooctyltin. 

Monomethyltin trichloride Dimethyltin dichloride Monobutyltin trichloride Dibutyltin dichloride Monooctyltin trichloride Dioctyltin dichloride... 

Organotin compounds such as monobutyltin oxide, the main substance used, accounting for 70% of consumption, dibutyltin oxide, monooctyltin oxide, and dioctyltin oxide are used in certain esterification and transesterification reactions, at concentrations between 0.001% and 0.5% by weight. They are used in the production of substances such as phthalates, polyesters, alkyd resins, fatty acid esters, and adipates and in trans-esterifications. These substances are in turn used as plasticizers, synthetic lubricants, and coatings. Organo-tins are used as catalysts to reduce the formation of unwanted by-products and also provide the required colour properties (ETICA, 2002). 

Industry has indicated that the number of production lines undertaking coating of glass bottles with monobutyltin trichloride is around 500, with an estimated 2000 production lines worldwide. Sites in the EU could be expected to use a little over 1 tonne of monobutyltin trichloride per year on average. 

Monobutyltin (EHMA) 69% degradation in 28 days Readily biodegradable ... 

The highest levels of monobutyltin and dibutyltin in water and sediment are thought to relate mainly to degradation of tributyltin from its use on boats as an antifouling paint. 

MMT, monomethyltin DMT, dimethyltin MBT, monobutyltin DBT, dibutyltin TBT, tributyltin MOT, monooctyltin DOT, dioctyltin... 

MMT, monomethyltin DMT, dimethyltin MBT, monobutyltin DBT, dibutyltin TBT, tributyltin MOT, monooctyltin DOT, dioctyltin Exposure via house dust (which has been measured as containing organotins) was also considered it is likely that inhalation exposure indoors includes house dust, which picks up leached organotins from vinyl flooring. 

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). 

Monobutyltin Rat Oral 2200 mg/kg body weight Sobering AG (1969a)... 

Studies of the effects of in vitro exposure to a range of concentrations (encompassing environmentally relevant concentrations of monobutyltin, dibutyltin, and tributyltin) on human natural killer lymphocytes obtained from adult male and female donors revealed the presence of detectable concentrations of the butyltins in all the donors, indicating possible exposure of natural killer cells to butyltins in the blood. It was suggested that the study provided evidence that butyltin compounds significantly inhibit natural killer cell function and possible natural killer cell-mediated potential in humans (Whalen etal, 1999). 

Monobutyltin Rat MBTC Gestation days 7-17at0, 50, 100, 200, and 400 mg/kg body weight Maternal toxicity thymic atrophy dose-dependent developmental toxicity fetuses with visceral or skeletal abnormalities NOAEL >400 Noda etal. (1992)... 

MMTC, monomethyltin trichloride DMTC, dimethyltin dichloride MBTC, monobutyltin trichloride DBTC, dibutyltin dichloride MOT, monooctyltin MOTC, monooctyltin trichloride MOT(IOMA), monooctyltin bis(isooctyl mercaptoacetate) DOT, dioctyltin DOTC, dioctyltin dichloride DOT(IOMA), dioctyltin bis(isooctyl mercaptoacetate)... 

Hamasaki et al. (1992) reported that monobutyltin oxide, monobutyltin trichloride, and dibutyltin dichloride showed high SOS-inducing potency in the SOS chromotest with iiic/rerrc/rra co/r PQ 37. Dibutyltin dichloride and dimethyltin dichloride were also recognized as producing DNA damage by the rec-assay in Bacillus subtilis H 17 Rec and M45 Rec. Li et al. 

Monobutyltin No data available No. NOAELs >400-2000 mg/kg body weight per day (as MBTC) No aromatase inhibition in vitro No data available... 

Monobutyltirr. Four acute toxicity studies were identified for monobutyltin chloride. The critical study was an acute EC50, based on immobilization, for Daphnia magna at a concentration of 25 mg/1. All four tests were acute, and, in the absence of long-term tests, it was decided to apply an uncertainty factor of 1000. 

Hermosin MC, Martin P, Cornejo J (1993) Adsorption mechanisms of monobutyltin in clay minerals. Environmental Science and Technology, 27(12) 2606-2611. 

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