- Gas-phase pyrolysis of 1-chloro-1-fluoro-2-methylcyclopropanes in the presence of SiO2 or Al2O3 with the formation of 2-chloro- or 2-fluorobuta-1,3-dienes
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Gas-phase pyrolysis of of 1-chloro-1-fluoro-2-methylcyclopropanes in an empty or filled with quartz pieces flow-tube reactor at 430 - 460 °C gives 2-fluorobuta-1,3-dienes (in 42 - 75% yields), whereas pyrolysis in the presence of Al2O3 at 150 - 250 °C gives 2-chlorobuta-1,3-dienes as the major products (in 58 - 68% yield).
- Volchkov,Lipkind,Novikov,Nefedov
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- Thermal cyclopropyl—allyl rearrangement of gem-chlorofluorocyclopropanes under gas-phase pyrolysis conditions. Formation of chlorofluoroalkenes and 2-fluorobuta-1,3-dienes
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The gas-phase pyrolysis of isomeric 2-chloro-2-fluoro-1-phenylcyclopropanes in a flow reactor at 250–430 °С gives 1-phenyl- and 3-phenyl-3-chloro-2-fluoropropenes. Under similar conditions, methyl-substituted gem-chlorofluorocyclopropanes undergo cyclopropyl—allyl isomerization accompanied by dehydrochlorination to form chlorofluoroalkenes and 2-fluoro-buta-1,3-dienes.
- Volchkov,Lipkind,Nefedov
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p. 1391 - 1401
(2019/08/12)
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- [5]Radialene
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The [n]radialenes are a unique family of fundamental [n]-membered carbocyclic structures with radiating alkenes, which have attracted significant synthetic and theoretical attention. Whereas [3]-, [4]-, and [6]radialenes have been prepared and studied, all efforts to synthesize the five-membered ring compound have thus far met with failure. Here we describe the first synthesis of the fundamental hydrocarbon [5]radialene, C10H10. Our approach was a departure from previous radialene syntheses in that it utilized a low-temperature decomplexation of a stable organometallic compound, rather than high-temperature elimination or rearrangement. Our strategy was guided by analysis of previous radialene syntheses, which indicated rapid decomposition in oxygen, and ab initio calculations, which revealed an extraordinary susceptibility of [5]radialene to undergo Diels-Alder dimerization/polymerization. The origin of this susceptibility was traced to a small distortion energy associated with the formation of the transition structure geometry from the relaxed reactant monomers and to a narrow HOMO-LUMO gap.
- MacKay, Emily G.,Newton, Christopher G.,Toombs-Ruane, Henry,Lindeboom, Erik Jan,Fallon, Thomas,Willis, Anthony C.,Paddon-Row, Michael N.,Sherburn, Michael S.
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supporting information
p. 14653 - 14659
(2015/12/09)
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- AN IMPROVED PROCESS FOR THE PREPARATION OF 2,3,-DICHLORO 1,3,BUTADIENE FROM 1,3 BUTADIENE
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The present invention relates to an improved process for the production of 2,3-Dichloro 1,3-Butadiene which comprises Chlorinating Butadiene, in liquid phase, in the presence of chlorinated solvents and phase transfer catalyst, Distilling the solvent, Distilling the formed 3,4-dichlorobutene-1, 1,4-dichlorobutene-2; and 1,2,3,4-Tetrachlorbutane; under reduced pressure,chlorinating the separated 3,4-dichlorobutene-1 and 1,4-dichlorobutene-2 to give 1,2,3,4-Tetrachlorobutane.,double Dehydrochlorinating the 1,2,3,4-Tetrachlorobutane using methanol,alkali and inhibitors under atmosphere of 1% oxides of nitrogen in nitrogen atmosphere the total period of Dehydrochlorinating being in the range of 15-33 hours to give 2,3-Dichloro 1,3-Butadiene and separating methanol to get 2,3-Dichloro 1,3-Butadiene
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Page/Page column 6
(2011/06/16)
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- PROCESS FOR PRODUCTION OF 2,3-DICHLOROBUTADIENE-1,3
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2,3-dichlorobutadiene-1,3 of high purity is produced from 1,2,3,4-tetrachlorobutane by a process comprising the steps of dehydrochlorination, chlorination of the reaction product obtained in the dehydrochlorination step and subsequent separation of a 2,3-dichlorobutadiene-1,3 composition from the reaction product of the chlorination step.
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Page/Page column 5
(2009/07/10)
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- Preparation of halogenated phthalic anhydrides
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A process for the aromatization of 4-chlorotetrahydrophthalic anhydride and 4,5-dichlorotetrahydrophthalic anhydride which comprises heating a solution of either substance in the presence of activated carbon and in the partial absence of air.
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