Tetrabutyl tin

A plot of A7/y°(SnR4, g) against A///TRII, g), where R is alkyl, is presented in Figure 3 where the enthalpy-of-formation values used are both experimentally determined (Table 3) and calculated. The calculated values are for tetramethyl and tetraethyl tin and methane. As stated above, the enthalpy-of-formation values for tetraethyl tin may be incorrect. That the calculated value for tetraethyl tin results in a better linear fit with tetrapropyl and tetrabutyl tin is further confirmation of this supposition. And, as discussed for the alkyl germaniums, the methyl deviations of methane and tetramethyl tin are too different for their measured values to fit a linear relationship such as equation 7. 

EXAFS data indicated that tin was only surrounded by four platinum atoms at the same distance of 0.276 nm (Scheme 2.40). This result clearly indicates that tin is located on the metal surface and not in the bulk. For example, in a bulk Pt3Sn alloy tin is surrounded by 12 platinum atoms while in a surface alloy on a platinum bulk it is surrounded by six platinum atoms only. Note that such tin adatoms are always obtained when low amounts of tin are deposited on the metal. This is probably because tetrabutyl tin coordinates first on the metal atoms of the faces, which are the most hydrogenolyzing, rather than corner or edges for which the alkyl ligands remain coordinated to the tin. This fact will be very important in catalysis since it explains selective poisoning of metal particles (see below). 

Tetrabutyl tin (tin tetrabutyl) [1461-25-2] M 347.2, b 94.5-96"/0.28mm, 145"/llmm, 245-247°/atm, d 1.05, n 1.473. Dissolve in Et20, dry over MgSO4, filter, evaporate and distil under reduced pressure. Although it does not crystallise easily, once the melt has crystallised then it will recrystallise more easily. It is soluble in Et20, Me2CO. EtOAc and EtOH but insoluble in MeOH and H2O and shows no apparent reaction with H2O. [JOC 19 74 1954, JCS 1992 7954]. 

Tm Ts TAB TAED TBP TBT TCBT TCEP TeBT TIC TMDD TMSH TOC TOM TPDB, TXIB Trisnorhopane Trisnomeohopane Tetrapropylene-based alkylbcnzenes N,N,N, N -Tetraacetyl ethylenediamine Tributyl phosphates Tributyl tin T etrachlorobenzyltoluenes Tris(2-chloroethyl)phosphate Tetrabutyl tin Total ion chromatogram 2,4,7,9-Tetramethyl-5-decyne-4,7-diol T rimethylsulfoniumhydroxide Total organic carbon Terrestrial organic matter 2,4,4-Trimethylpentane-1,3-dioldi-/.vo- butyrate... 

Additionally, significant variations of the standard deviation values were observed with respect to the individual compounds. The precision of S13C-values of n-alkanes, 2,2,4,4,6,8,8-heptamethylnonane, fatty acid methyl esters, phthalates and musk fragrances was generally acceptable down to amounts of approx. 5 ng with standard deviation values below 1.0 %o. On the contrary, already at the 25ng- and lOng-levels the stable carbon isotope ratios of the chlorinated compounds (CI5- and Cf,-benzene, Clfi-butadiene) as well as of tetrabutyl tin were measured with high standard deviations between 0.8 %o and 3.2 %o. 

A well known Elbe-specific compound is tetrabutyl tin, the parent substance for the synthesis of mono- to tributyl tin compounds widely used as antifoulants, stabilizers in poly(vinyl chloride)s (PVC) and industrial as well as agricultural biocides. The origin of tetrabutyl tin in sediments and suspended particulate matter of the Elbe river can be linked to an industrial point source situated near the confluence of the Mulde and the Elbe rivers (Wilken et al. 1994, Schwarzbauer, 1997). The occurence of tetrabutyl tin not only at sample sites mainly influenced by the Elbe river (sample sites A,B and C), but also in sediments situated farer from the Elbe estuary (sample sites E,F) indicates a wide spatial distribution of Elbe-derived organic matter in the German Bight. 

Also, an isomeric mixture of alkylsulfonic acid phenylesters, the individual contaminants tetrabutyl tin and l,2,3,6,7,8-hexahydro-l,l,6,6-tetramethyl-4-isopropyl-as-indacene as well as degradated compounds of DDT could be attributed to the group of Elbe-specific marker compounds. 

The concentrations of tetrabutyl tin range from 130 pg/kg TOC at sample site B to 14 pg/kg TOC at sample sites E and F and is below the LOQ at sample site D. The emission of this well known Elbe-specific compound was formerly linked to an industrial point source situated near the confluence of the Mulde and the Elbe rivers (Wilken et al., 1994, Schwarzbauer, 1997). Mono- and disubstituted chloronaphthalenes were also detected with concentrations between the LOQ at sample sites not influenced by Elbe derived contaminations and 70 and 100 pg/kg TOC at sample site B. These low chlorinated naphthalenes occur in the sediments with patterns similar to those of technical agents (e.g. Halowax 1000) and were formerly identified with comparable isomer distributions in sediments of the Elbe river and its tributaries (Schwarzbauer 1997, Schwarzbauer et al. 2001). On the contraiy the origin of the Elbe specific contaminant 4,4 -d ic h Iorodiphcnylsul tidc detected at sample sites A,B,C,E and F with concentrations ranging from 7 to 45 pg/kg TOC is still unknown. 

Pesticides and bacteriocides Metallorganic compounds Dichlorobenzonitrile Tetrabutyl tin Methyltriclosan ... 

This study described the application of a common analytical procedure adapted for compound-specific stable carbon isotope analyses of riverine contaminants. To evaluate the sensitivity of the analytical method and the precision of the isotopic data obtained a set of numerous substances at different concentration levels were measured. For most of the anthropogenic contaminants investigated (including chlorinated aliphatics and aromatics, musk fragrances, phthalate based plasticizers and tetrabutyl tin) acceptable carbon isotope analyses could be obtained down to amounts of approx. 5 ng. These amounts correspond to concentrations in water samples at a natural abundance level of low to medium contaminated river systems. However, it has to be considered that the accuracy as well as the sensitivity of the analytical method depend partially on the chemical properties of the substances measured. 

TETRABUTYLTIN or n-TETRABUTYL TIN (1461-25-2) Combustible liquid. Strong oxidizers or strong acids may cause fire and explosions. Attacks some forms of plastics, rubber, and coatings. 

Tin oxide films have been deposited onto soda-lime-silica glasses in a cold-wall reactor at substrate temperatures between 350°C and 490°C [108]. The mechanism of formation was carefully studied using four different tin alkyls as starting compounds namely dibutyl tin diacetate (DTD), tetrabutyl tin (TBT), tetraethyl tin (TET) and tetramethyl tin (TMT). The investigations showed for the mechanism a dependence on the molecular structure and reactivity of the initial tin compound to oxygen. The influence of substrate temperature on deposition rate (Arrhenius plots) showed three characteristic regions for which three processes were proposed [108] ... 

After characterization of the metal by electron microscopy and chemisorption methods such as hydrogen, oxygen, and carbon monoxide adsorption, the reaction with tetrabutyl tin was performed and followed by GC and volumetry. The reaction... 

A similar effect was observed during the dehydrogenation reaction of butan-2-ol into methyl ethyl ketone on Raney nickel (Scheme 11). Raney nickel is a very efficient catalyst for this reaction and leads to methyl ethyl ketone with a selectivity of ca 90%. This result is good but for industrial applications higher selectivities are required. This can be achieved by poisoning some sites by reaction with tetrabutyl tin (the best results are obtained with an Sn/Ni ratio of 0.02). Indeed, the reaction... 

Apart from Ru-catalyzed metathesis in ionic liquids two examples of tungsten catalyzed metathesis reactions have also been reported. Vasnev and coworkers studied the metathesis of Thexene catalyzed by WCle in tetrafluoroborate ionic liquids [266]. In the reaction sequence under investigation, l-hexene first isomerized to 2-hexene which then formed 4-octene and ethylene by cross-metathesis. The yields of the metathesis product were demonstrated to increase with increasing reaction temperature and with addition of a tin-containing promoter. 4-octene was obtained in selectivies up to 97% (at 25% l-hexene conversion) when tetrabutyl tin was applied as the promoter in this reaction. 

First there is physisorption of tetrabutyl tin on the surface of the support. This is well proved, in the case of siUca [61] by infrared spectroscopy which shows a strong shift to lower wavenumbers of the v(0—H) band of silica from 3760 cm" ... 

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