- Process for isomerizing dichlorobutenes
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This invention relates to a process for isomerizing 1,4-dichloro-2-butene to yield 3,4-dichloro-1-butene or 3,4-dichloro-1-butene to yield 1,4-dichloro-2-butene, characterized in that the catalyst used comprises a compound of the formula CpFe(CO)2X, wherein Cp denotes a cyclopentadienyl derivative of the general formula (I), wherein R1to R5mutually independently denote H, C1to C12alkyl, C5to C8cycloalkyl, which may in turn bear C1to C12alkyl groups, C6to C14aryl, alkylaryl, arylalkyl, wherein two adjacent residues may together form saturated or unsaturated C3to C14cycles, or denote—SiR6R7R8, wherein R6to R7may mutually independently mean C1to C4alkyl, C5to C8cycloalkyl or C6to C14aryl, and X denotes F, Cl, Br.
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Page column 4-6
(2008/06/13)
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- Alkylations of Trichloromethylketones Effected by Trichloroacetate and a Complex Consecutive Reaction
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A phase transfer reaction between the title ketones, sodium trichloroacetate, and an alkyl halide leads to 2a, b, 4, or 5.Whereas these compounds are fragmented by NaOH, sodium methoxide/methylmalonate/methanol give compound 8 from 5 in a complex series of consecutive rearrangements. - Key words: Trichloromethylketones, Phase Transfer Reaction
- Dehmlow, Eckehard V.,Raths, Hans-Christian
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p. 918 - 920
(2007/10/02)
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- INTERACTION OF 1,4-DICHLORO-2-BUTENE WITH AQUEOUS NaOH AND Na2CO3 SOLUTIONS.
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In large-tonnage industrial production of choloroprene (CP) from butadiene, at the stage of aqueous-alkaline dehydrochlorination of 3,4-dichloro-1-butene (3,4-DC-1-B) containing up to 2 mass % of isomeric 1,4-DC-2-B as an impurity from 0. 5 to 2. 5% of oxygen-containing compounds are formed, including chlorohydrins, diols, acetaldehyde, epoxybutenes, etc. They contaminate the product ( beta -CP), hinder purification of mineralized wastes, and take part in secondary reactions of dimerization and polycondensation. The authors examine the relationships and kinetic characteristics of reactions involved in the interaction of 1,4-DC-2-B with aqueous alkali solutions. Comparison of the initial process rates in the presence and absence of the phase-transfer catalyst (PTC) shows that the latter has virtually no influence on hydrolysis. The rate of consumption of 1,4-DC-2-B in the reaction with aqueous NaOH solutions in presence of PTC is described by an equation consisting of two terms: the hydrolysis rate r//1, determined from an equation of the second order, and the rate of catalytic dehydrochlorination r//2.
- Zabrodina,Levanova,Revyakin,Ermakov,Rodova
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p. 618 - 620
(2007/10/02)
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- Thermolysis of vinyl chloride in nitrogen; rates and products between 601-681 deg C
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In a 10-15-fold excess of nitrogen, at normal pressure and with τ ca. 3 s, decomposition of vinyl chloride (VC) sets in at about 550 deg C.At 680 deg C about 35percent decomposition takes place.Major products in this region are HCl, acetylene, 2-chlorobutadiene and vinylacetylene (1-buten-3-yne).At higher temperatures formation of tar and soot becomes increasingly important.A reaction mechanism in accord with the experimental facts is proposed and analyzed via thermochemical kinetics.Free-radical chain processes play a major part, with Cl. leads to.CH=CHCl and CH2=C.Cl radicals, respectively.Their relative rate of formation on a per-H basis is ca. 1/5 around 620 deg C.The former lose Cl. to give acetylene.The latter add to VC which leads to 2-chlorobutadiene irrespective of the site of addition (Scheme 1).Various routes to vinylacetylene are discussed.The formation of other (minor) products such as ethylene and methyl chloride is also rationalized.Added HCl is seen to increase the acetylene/2-chlorobutadiene product ratio with little effect on the rate of conversion of VC.This is due to reversal of the reaction leading to CH2=C.Cl radicals, through H-atom transfer from HCl.
- Manion, Jeffrey A.,Louw, Robert
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p. 442 - 448
(2007/10/02)
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- Methyl-halogenated Allyl Methyl Sulfoxides and Sulfones and the Synthesis of Halogenated Sulfines
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Allyl methyl sulfoxides R1R2R3C-S(O)-CH2CH=CH2 1a-7a (R1, R2, R3 = H, F, Cl, CF3) as well as the corresponding sulfones 1b-7b were synthesized.The sulfoxides substituted at the methyl group are in equilibrium with the allyl sulfenates R1R2R3-S-OCH2CH=CH2 depending on temperature and kind of substitution.By pyrolysis of the sulfoxides 2a, 3a, 4a, and 7a the sulfines Cl2C=SO and (CF3)2C=SO could be prepared, and evidence for the existence of the sulfines ClFC=SO and F2C=SO could be obtained.The new pentenes 12 and 14 are described.
- Holoch, Jan,Sundermeyer, Wolfgang
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p. 269 - 278
(2007/10/02)
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