- Synthesis of chlorothioformates from xanthates
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The Vilsmeier reagent derived from N-formylmorpholine produces chlorothioformates from primary and secondary alkyl xanthates. The major side products are the corresponding alkyl chlorides. Secondary alkyl chlorothioformates give lower yields due to their instability. Treating xanthates with other common chlorinating agents (oxalyl chloride, thionyl chloride) gives only dialkyl thiodicarbonates. Georg Thieme Verlag Stuttgart.
- Fikse, Megan A.,Bylund, William E.,Holubowitch, Nicolas E.,Abelt, Christopher J.
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p. 4118 - 4120
(2008/03/13)
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- Oxidation of monohydric and dihydric alcohols with CCl4 catalyzed by molybdenum compounds
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Mo(CO)6 catalyzed oxidation of alcohols and diols with tetrachloromethane. Primary oxidation products in reaction of alcohols with CCl4 are alkyl hypochlorites, and final products depending on the structure of initial alcohol are aldehydes (as acetals), ketones, chloroketones, and esters.
- Khusnutdinov,Shchadneva,Burangulova,Muslimov,Dzhemilev
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p. 1615 - 1621
(2007/10/03)
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- Oxidative alkoxylation of zinc phosphide in alcoholic solutions of copper(II) chloride
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Oxidative alkoxylation of Zn3P2 with the formation of valuable phosphoric and phosphorous acid esters occurred at a high rate and with a high selectivity in alcoholic solutions of CuCl2 under the action of oxygen at 30-60°C. Depending on the nature of the alcohol, two products were formed, namely, trialkyl phosphates (RO)3PO and dialkyl phosphites (RO)2HPO. Water favored the formation of dialkyl phosphates (RO)2(HO)PO. The kinetics and mechanism of the new catalytic reaction were studied, and the optimal conditions for conducting this reaction were found. The reaction proceeded in a topochemical mode by a separate redox mechanism.
- Dorfman,Ibraimova,Polimbetova
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- CHLORINATION OF PHOSPHINE IN ALCOHOLS
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Trialkyl phosphates are rapidly and selectively formed when dilute gaseous PH-Ar and Cl2-Ar mixtures are passed into alcohols (ROH, R=Bu, i-Bu, Am, i-Am, Oct) at 50-70 deg C.Analogous results are obtained in the presence of pyridine at 8-25 deg C.The reaction was studied by gas chromatography, 31P NMR spectroscopy, and potentiometry.The reaction was shown to pass successively through the stages of the chlorination of phosphine to PCl5, the alcoholysis of phosphorus pentachloride to phosphoryl chloride, and finally by the esterification of phsophoryl chloride to trialkyl and dialkyl phosphates.Pyridine, excess af alcohol, and high temperature accelerate the stage of the esterification of phosphoryl chloride to the trialkyl phosphate.
- Dorfman, Ya. A.,Polimbetova, G. S.,Aibasov, E. Zh.,Borangazieva, A. K.,Kokpanbaeva, A. O.,Faizova, F. Kh.
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p. 1860 - 1864
(2007/10/02)
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- SYNTHESIS AND TRANSFORMATIONS OF α-HYDROXY HYDROPEROXIDES OF 1,1-DIALKOXY-2-PROPANONES, CATALYZED BY Fe(II) IONS
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The reaction of 1,1-dialkoxy-2-propanones with hydrogen peroxide at -8 deg C leads to 1,1-dialkoxy-2-hydroxy-2-hydroperoxypropanes, the decomposition of which catalyzed by Fe(II) ions at 0-5 deg C leads to the formation of acetic acid, alkyl formates with yields of 25-30percent, and the corresponding alcohols with yields of 45-50percent and with ca.85percent conversion of the initial compounds.If the reactions are conducted in a saturated aqueous solution of sodium chloride or potassium thiocyanate, the alkyl chlorides (yields 9-12percent) or alkyl thiocyanates (yields 10percent) are formed in addition to the alcohols (yields 30-35percent).
- Kasatkina, A. A.,Galeeva, A. G.,Zorin, V. V.,Rakhmankulov, D. L.
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- Processes using a phosphorus complex
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A process for chlorinating compounds containing a carbon atom bonded to a hetero-atom selected from the group consisting of oxygen, nitrogen and sulfur; said process comprises contacting the carbon hetero-atom containing compound with a chloro phosphorus complex of the formula wherein R is selected from the group consisting of aryl, substituted aryl, alkyl and substituted alkyl, so that the hetero-atom is replaced by at least one chlorine atom; compounds capable of being chlorinated can include, for example, carboxylic acids, acid chlorides, ketones, aldehydes, alcohols, epoxides, esters, anhydrides, ethers, thiols, and aromatic nitro groups; the reaction can be extended to compounds containing the carbon to chlorine bond alpha to a carbon atom containing at least one hydrogen atom, it can be further dehydrochlorinated, e.g., by either heating to a temperature ranging from about 50° C. to about 300° C. or by reaction with a base selected, e.g., from alkali metal hydroxides and alkoxides.
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- Silylaminyl Radicals. Part 2. Free Radical Chain Halogenation of Hydrocarbons using N-Halogenobis(trialkylsilyl)amines
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The liquid-phase halogenation of a number of hydrocarbons and of 1-chlorobutane by N-halogenobis(trialkylsilyl)amines has been studied using product analysis techniques.The reactions take place by free radical chain mechanisms which involve the propagation steps generalised in equations (A) and (B) (X=Br or Cl).At 353 K, the molar reactivities of toluene (benzylic C-H) and cyclohexane towards (R3Si)2N+RH(R3Si)2NH+R (A) R+(R3Si)2NXRX+(R3Si)2N (B) (Me3Si)2N are approximately equal and toluene is 5.2 times more reactive than perdeuteriotoluene.The relative rates of hydrogen abstraction by (Me3Si)2N and (ButMe2Si)2N from the primary, secondary, and tertiary C-H groups in 2-methylbutane show that the silylaminyl radicals are not only highly reactive but also sterically demanding.Thus, at 333 K the average primary C-H reactivity is 0.6 times that of the tertiary C-H towards attack by (Me3Si)2N, but 4.2 times that of the tertiary C-H towards attack by the more bulky (ButMe2Si)2N.Silylaminyl radicals are much more reactive in hydrogen abstraction than are analogous dialkylaminyl radicals and this difference is interpreted in terms of thermodynamic and polar effects which arise because of the ?-donor-?-acceptor nature of the trialkylsilyl substituent.
- Cook, Malcolm D.,Roberts, Brian P.,Singh, Karamjit
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p. 635 - 644
(2007/10/02)
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- Selectivity in the Halogenation of Hexane by Tertiary Aminium Radicals from the Photodecomposition of N-Halogenoammonium Perchlorates
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The photochlorination of hexane with tertiary N-chloroammonium perchlorates in trifluoroacetic acid gives monochlorohexanes in high yield and with a striking preference for the 2-isomer.It is shown that free-radical chains are involved in which hydrogen-atom abstraction is by tertiary aminium radicals.The marked preference for 2- compared with 3-chlorination is attributed mainly to the bulky aminium radical attacking the relatively more accessible 2-position; an alternative explanation involving a reversible hydrogen-atom abstraction is ruled out.The magnitude of the primary deuterium kinetic isotope effect in these photochlorinations gives information about the dependence of the extent of C-H bond breakage in the transition state on the structure of the abstracting aminium radical.
- Fuller, Steven E.,Smith, John R. Lindsay,Norman, Richard O. C.,Higgins, Raymond
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p. 545 - 552
(2007/10/02)
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- Studies on Sulphochlorination of Paraffins. IX. Regularities of the Sulphochlorination of Branched-chain Paraffins
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In the cases of 2-methylbutane and 2-methylpentane the formation of tertiary sulphochlorides in the sulphochlorination of the parent hydrocarbons could be established by means of 13C-n.m.r.-spectroscopy.The relative rates of the various C-H-bonds in 2-methylbutane, 2-methylpentane and 3-methylpentane in the sulphochlorination reaction were determined.The relative rates of the tertiary C-H-bonds in the sulphochlorination were considerably lower than the corresponding values for the chlorination of the branched-chain paraffins.
- Estel, D.,Mateew, K.,Pritzkow, W.,Schmidt-Renner, W.
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p. 262 - 268
(2007/10/02)
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