The free-radical reaction of tri-n-butyltin hydride with disulfides

The kinetics and absolute rate constants for the free-radical chain reaction of tri-n-butyltin hydride with di-t-butyl disulfide have been measured in cyclohexane at 30°. The rate controlling step for chain propagation involves the cleavage of the disulfide bond by an attacking tributyltin radical. The rate constant for this bimolecular homolytic substitution at sulfur is ～8 × 10⁴ Mole^?1 sec^?1. Chain termination involves the self-reaction of two tributyltin radicals. The rate constants for attack of tributyltin radicals on some other disulfides and on elemental sulfur have also been measured. The results are compared with literature data for homolytic substitutions on these compounds by a variety of radicals which have their unpaired electron centered on carbon.     

The cyclization reaction of 5-hexenoyl chloride with tri-n-butyltin hydride

The title reaction under various conditions of solvent, temperature and concentration was found to give 1,5 cyclization product and the typical acyclic reduction products.     

Use of high pressure in the reduction of organic chlorides with tri-n-butyltin hydride

The use of the high pressure technique enables reduction of organic halides by tri-n-butyltin hydride to be carried out in the absence of a catalyst or free radical initiator. It leads to a better conservation of the structure of the starting material during the reduction. In the case of some unsaturated halides, a new chemoselectivity has been observed in favour of the addition of the hydride on the carboncarbon double bond.     

Determination of tri-n-butyltin in oysters by reaction-gas chromatography of hydride derivatives

A reaction-gas chromatography method for determining tri-n-butyltin (TBT) as the hydride derivative has been adapted to allow determination of TBT in oysters. The extraction method has been modified to prevent fouling of the hydride formation reactor and the gas chromatography has been made faster by employing a different column and temperature program. The detection limit is 3-6 ng/g in oyster tissue. Apparent recoveries of TBT from oyster tissue at 25 and 125 ng/g levels are 107 and 97%, respectively.     

Reaction of tri-n-butyltin formate. III. Synthesis of allylic tri-n-butyltin by the reaction of tri-n-butyltin formate with allylic sulfones and sulfides.

Allylic tri-n-butyltins can be prepared easily by the treatment of allylic sulfones or sulfides with tri-n-butyltin formate in refluxing xylene.     

The reaction of acyl peroxides with 2,2,6,6-tetramethylpiperidinyl-1-oxy

Benzoyl ana lauroyl peroxides undergo induced decomposition by 2,2,6,6-tetramethylpiperidinyl-1-oxy to form acyloxy radicals and carboxylic acid in equimolar amounts. Formation of the carboxylic acid does not involve free acyloxy radicals.     

A free-radical reaction of alkanoic acids with tetrachloroethylene

The di-tert-butyl peroxide-initiated free-radical reaction of C₃-C₆ alkanoic acids with tetrachloroethylene results in the formation of a mixture of isomeric (trichlorovinyl)alkanoic acids with the predominant isomer bearing the trichlorovinyl group at the (–1) position.Translated fromIzveshya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 1011–1013, April, 1996.     

Reactive blending of bioaffine polyesters through free-radical processes initiated by organic peroxides

Reactive polymer blending of poly(β-hydroxybutyrate) (PHB) and its valerate copolymers (PHBV) are reported, following two different methodologies, namely polymerization of rubber inclusions in the preformed matrix or reactive melt blending of preformed polymers. As second phase, poly(butyl acrylate) (PBA) and polycaprolactone (PCL) are used. The results of spectroscopic, thermal, mechanical and morphological analysis indicate the existence of chemical interactions between the blend components. Such interactions are also responsible of a drastic change in the morphology.     

On the free-radical reaction of primary alcohols with formaldehyde

Conclusions The reaction of primary alcohols with formalin or paraformaldehyde initiated by t-butyl peroxide in a glass apparatus under atmospheric pressure leads to the formation of alkane-1,2-diols.Co-worker at the French National Center of Scientific Research (Laboratoire de Lipochimie, CNRS, Paris).Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1271–1272, July, 1966.     

The reaction of lithiun aluminium hydride with carbon dioxide or sodium bicarbonate

The reaction of LiA1H₄ with CO₂ or NaHCO₃ at elevated temperatures has been investigated. Methane and ethylene are the primary products of each reaction. These molecules are probably the “explosive” reaction products formed when CO₂ fire extinguishers are used on LiAlH₄ fires.     

Singlet oxygen production in the reaction of superoxide with organic peroxides

[reaction: see text] A selective chemiluminescent probe for singlet oxygen has been employed to detect and quantify singlet oxygen in the reactions of superoxide with organic peroxides. The production of singlet oxygen has been quantified in the reaction of superoxide with benzoyl peroxide (BP). No singlet oxygen was detected in the reactions of superoxide with cumyl peroxide, tert-butyl peroxide, or tert-butyl hydroperoxide. On the basis of these results and on the temperature dependence of the reaction, we proposed a mechanism for singlet oxygen formation in the reaction of superoxide with BP.     

The acute toxicity of tri-n-butyltin glycocholate

The oral acute toxicity for tri-n-butyltin glycocholate (TBT-GA), a newly synthesized organotin steroid, was determined using Long Evans rats. The compound was suspended in corn oil and adminstered by gavage using standard techniques. Unlike tri-n-butyltin taurocholate, which exhibited two different toxicities, one for the tri-n-butyltin moiety and one for the taurocholic acid moiety, the TBT-GA exhibited a single toxicity, that of the whole molecule. The LD₅₀ value was 213 mg kg^?1 (0.274 mmol kg), which on a millimolar basis is similar to that observed for other tri-n-butyltin compounds. The dead rats exhibited distended stomachs, enlarged ceca, and lesions in the intestinal tract. The actual cause of death could not be positively identified. Animals that survived more than three days also exhibited time- and dose-related atrophy of the thymus gland. With 36% more male than female rats succumbing to TBT-GA, the chemical appears to be more toxic towards male than female rats.     

The acute toxicity of tri-n-butyltin taurocholate

The acute toxicity for tri-n-butyltin taurocholate (TBT-TA), a newly synthesized organotin steroid, was determined using Long Evans rats. The organotin compound was suspended in corn oil and administered by gavage using standard techniques. The TBT-TA exhibited a taurocholic acid toxicity at 24 h and a tributyltin toxicity at three days. The LD₅₀ values were 611 and 384 mg kg^?1 respectively. The dead rats exhibited distended stomachs, enlarged cecums, and lesions in the gastrointestinal tract. The toxicity is similar to that observed with other trialkyltin compounds.     

Chemiluminescence and free-radical stages of the Belousov-Zhabotinskii reaction

The profound effect of stirring on chemiluminescence of the system: bromate-malonic acid-ruthenium complexes with low (10^–5 M) catalyst concentrations indicates the significant contribution of organic radicals R^. to the oscillation mechanism. Critical radical concentration for this oscillation is [R^.]_C<7×10^–10 M.

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: - - (10^–5 M) . R^. : [R^.]_C<7×10^–10M.