- KINETICS AND MECHANISM OF THE SYNTHESIS OF DIFLUOROBENZENES BY THERMAL REACTION OF DIFLUOROCARBENE WITH BUTADIENE
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Reaction of butadiene with difluorocarbene, resulting in the formation of difluorobenzenes, and its main steps have been systematically studied.The kinetics of thermal conversions of intermediately formed 2,2-difluorovinylcyclopropane and 2,2,3,3-tetrafluorovinylcyclobutane has been examined.The synthesis of difluorobenzenes has been optimized.The results obtained are used as a basis for domestic technology of production of difluorobenzenes.
- Shipilov, A. I.,Zabolot-skikh, V. F.,Nefedov, O. M.
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- Synthesis and aromatization of 2+2 cycloadducts of butadienes and tetrafluoroethylene
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Passing tetrafluoroethylene (TFE) and hydrocarbon dienes down a hot tube at 600 deg C with a contact time of a few seconds produces substituted fluorobenzenes.Specifically, tetrafluoroethylene and butadiene form 1,2-difluorobenzene.The aromatics produced bythe pyrolysis of TFE and methyl-substituted butadienes do not necessarily result from eliminating HF from 2+4 adducts of the starting materials.Solid-acids such as alumina or silica/alumina accelerate the ring-expansion elimination of the 2+2 cycloadducts.Aromatic products result from the preformed 2+2 cycloadducts at temperatures 200 deg C lower than the corresponding thermal reaction.The solid-acids can also influence product regiochemistry.
- Weigert, F. J.,Davis, R. F.
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