Tetra-»-butyltin

The submitters report that the same yields in terms of percentages are obtained if the procedure is applied to the preparation of tetra-w-propyltin and tetra- -butyltin. 

Tin is a frequently used metal for plating, soldering and in alloys. It is also produced in different organic forms, such as tri- and tetra-butyltin for use as... 

The calibration technique of standard addition is often used to minimize matrix effects in the quantification of organotins. External calibration is also used by many groups, howeveg the use of an internal standard is highly recommended with the nature of the best compound to use dependent on the measurement system involved. Tripropyltin chloride has been used by many groups as a surrogate to monitor the whole method process, and species such as tetra-butyltin and tetrapentyltin have been used as internal standards added just prior to GC analysis. 

Fig. 6. Gas chromatogram of butylvinyltin compounds. Peak 1 dodecane, 2 dibutylvinyltin, 3 tributylvinyltin, 4 tetra-butyltin, tributyltinchloride.

Mono-, di-, tri- and tetra-butyltin signals from a spiked water sample at... 

With trifluoroacetic acid at 80° C di-n-butylbis(pentafluoroethyl)tin yielded only about 7% of its butyl groups as butane. Under similar conditions a sample of tetra- -butyltin gave butane in nearly 50% yield 29). It is evident that (n-C4H9)2Sn(C2Fs)2 is more similar to ( -C4H9)2SnCl2 than to (n-C4H9)4Sn. 

FIGURE 5.6 Supercritical fluid chromatogram showing the separation of (1) tetra-butyltin, (2) tributyltin chloride, (3) triphenyltin chloride, and (4) tetraphenyltin. 

The preparation of thiols by nucleophilic displacement reactions using aqueous potassium or sodium hydrogen sulphide under catalytic conditions is not particularly effective. A limited number of simple alkane thiols have been obtained under mild and neutral conditions in moderate yield (70-80%) from the reaction of bis(n-butyltin) sulphide with bromoalkanes in the presence of a ca. twofold amount of tetra-n-butylammonium fluoride [1], but there has been no exploitation of this procedure. 

The influence of temperature on the ortho effect has been evaluated in the alkaline hydrolysis in aqueous DMSO solutions of ortho-, meta- and para-substituted phenyl benzoates (26). The alcoholysis of phthalic anhydride (27) to monoalkyl phthalates (28) occurs through an A-2 mechanism via rate-determining attack of the alcohol on a carbonyl carbon of the anhydride (Scheme 4). Evidence adduced for this proposal included highly negative A 5 values and a p value of 4-2.1. In the same study, titanium tetra-n-butoxide and tri-n-butyltin ethanoxide were shown to act as effective catalysts of the half-ester formation from (27), the mechanism involving alkoxy ligand exchange at the metal as an initial step. ... 

For the determination of organotin compounds (tributyltin, triphenyltin, triethyltin, and tetra-ethyltin) a MAE is proposed before the normal phase (NP) HPLC/UV analysis [35], In organotin and arsenic speciation studies, hydride generation is the most popular derivatization method, combined with atomic absorption and fluorescence spectroscopy or ICP techniques [25,36], Both atmospheric pressure chemical ionization (APCI)-MS and electrospray ionization ESI-MS are employed in the determination of butyltin, phenyltin, triphenyltin, and tributyltin in waters and sediments [37], A micro LC/ESI-ion trap MS method has been recently chosen as the official EPA (Environmental Protection Agency) method (8323) [38] it permits the determination of mono-, di-, and tri- butyltin, and mono-, di-, and tri-phenyltin at concentration levels of a subnanogram per liter and has been successfully applied in the analysis of freshwaters and fish [39], Tributyltin in waters has been also quantified through an automated sensitive SPME LC/ESI-MS method [40],... 

The values of k2 and k°2s given in Tables 16 and 17 for brominolysis of tetra-n-propyltin and tetra-n-butyltin enable a value for K, the equilibrium constant for reaction (32), to be estimated using equation (31). Under the conditions given in Table 17, K is found to be 82 l.mole-1, in fair agreement with the reported22 value of 52 l.mole-1. at 25 °C (see Table 2, p. 139). 

IODINOLYSIS OF TETRA-M-BUTYLTIN BY IODINE IN SOME NON-POLAR... 

FOURTH-ORDER RATE COEFFICIENTS (l3.mole 3.min ) FOR THE IODINOLYSIS OF TETRA-rt-BUTYLTIN AT 20 °C48... 

Tetra-n-butyltin is oxidised by chromium trioxide (1 1 molar ratio) to yield tri-n-butyltin acetate and compounds derived from the n-butyl group cleaved from the tin atom (mainly n-butyraldehyde and butyric acid)29. In the initial stages of the oxidation, the reaction follows the simple rate expressions v = k2 [Bu Sn] [Cr03]. Values of the second-order rate coefficient for the oxidation of a number of tetraalkyitins by Cr03 in solvent acetic acid at 20 °C were reported29 to be as follows... 

Sodium borohydride-Palladium chloride. Sodium borohydride-Rhodium(lII) chloride. Sodium borohydride-Tin(II) chloride. Sodium cyanoborohydride. Sodium 9-cyano-9-hydrido-9-borabicyclo[3.3.1]nonane. Sodium dithionite. Sodium hydride-Sodium t-amyl oxide-Zinc chloride. Sodium trimethoxyborohydride. Tetra-/i-butylammonium borohydride. Tetra-n-butylammonium cyanoborohydride. Tetra-n-butylammonium octahydrotriborate. Tri-n-butyltin hydride. Triethoxy silane. Triisobutylaluminum-Bis(N-methyl-salicyclaldimine)nickel. Zinc borohydride. REDUCTIVE CYCLIZATION Cobaloximc(I). 

Monoetherification of polyols.12 Monobenzylation and monoallylation of polyols can be conducted conveniently under mild conditions by conversion to the stannylene derivative (dimeric) by di-n-butyltin oxide (5, 189 9, 141). The stannylene is then treated with benzyl bromide or allyl bromide and tetra-n-butylammonium iodide (1 equiv.) in benzene. The same conditions can be used to prepare monomethoxymethyl ethers. Quaternary ammonium bromides are less efficient catalysts than the iodides. These salts also accelerate reaction of stannylenes with acid anhydrides. The mechanism for this activation is not clear it may involve coordination of I" to tin. 

Zimmerli B, Zimmerman H. 1980. Gas-chromatographic determination of traces of butyltin compounds (tetra-, tri-, di-) in the air. Fresenius Z Anal Chem 304 23-27. (German)... 

The 119Sn chemical shift of trichlorobutyltin mixed with 1 equiv of methanol in CDCI3, was at —181 ppm with respect to the uncoordinated molecule (—141.2 ppm), which confirmed the pentacoordination. In esters, intermediate values may suggest an equilibrium between tetra- and pentacoordinated species, or a weak coordination. Besides, the 17(SnC) for butyltin trichloride in CDCI3, where the metal is tetracoordinated, is 648 Hz in comparison with 939 Hz in the presence of 1 equivalent of methanol433. 

Aceto(carbonyl)cyclopentadienyl(tri-phenylphosphine)iron. 3-Acylthiazolidine-2-thiones. Bis(cyclopentadienyl)titana-cyclobutanes. Bromomagnesium diisopro-pylamide. Cerium(III) chloride. Dichloro-phenylborane. Dimethylphenylsilyllithium. Ethylene chloroboronate. Ketene bis(trimethylsilyl)ketals. Mandelic acid. Norephedrine. Potassium fluoride-Alumina. (S)-(—)-Proline. Tetra-n-butylam-monium fluoride. Tin(IV) chloride. Tin(II) trifluoromethanesulfonate. Titanium(IV) chloride. Tri-n-butyltin fluoride. Trityl perchlorate. 

HOMOALLYLIC ALCOHOLS Allyl tri-methyltin. lodomethyltri-n-butyltin. (+)-3-Phenyl-2,3-bornanediol. Tetra-n-butylammonium fluoride. 

Cyclopropenone (I). Breslow and Oda" have effected the preparation and isolation of pure recrystallized cyclopropenone (I, m.p. —29 to —28 ) by reduction of tetra-chlorocyclopropenc in paraffin oil with tri-n-butyltin hydride under argon. A mixture... 

Thallium(I) cyanide was introduced by Taylor and McKillop as a reagent. Aromatic and heteroaromatic acyl cyanides are produced in go yield, whereas aliphatic acid halides lead under these conditions mainly to dimerization products. 18-Crown-6 is a good catalyst for the preparation of cyanoformate in methylene chloride with potassium cyanide and chloroformates. Similarly, tetraethylammonium cyanide gives cyanoformates in high yield under very mild conditions. Aroyl cyanides are generated easily by phase transfer catalysis with tetra-n-butylammonium bromide. Tri- -butyltin cyanide proved successful only with aromatic acid halides, leading to dimerization products with aliphatic compounds. ... 

Table 2-8 119Sn Chemical shifts for the diastereoisomers of tetra-2-butyltin.

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