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Reactions of some unsaturated fluorocarbon derivatives with organo compounds of phosphorus and nitrogen

University of British Columbia

Perfluorocyclobutene and 1,2-dichlorotetrafluorocylobutene react readily with diethylphosphine at 20° to give unstable mono-substitution products, 1-diethylphosphino-2-halotetrafluorocy-clobutenes. With tetramethyldiphosphine, low yields of 1,2-bis(dimethylphosphino)tetrafluorocyclobutene and trifluorodimethylphosphorane are obtained from the chloro- and perfluoro-butenes respectively. Diphenylphosphine also gives the 1,2-disubstituted product at 20°, from perfluorocyclobutene only. This olefin interacts with tetraphenyldiphosphine (130 ) to give 1-diphenylphosphinotrlfluorocyclobutenone (from 95% ethanol). Under identical conditions the chloro-butene reacts with the phenyl-phosphines to give trifluorodiphehylphosphorane and fluoro-diphenylphosphine oxide. Tetrakis (trifluoromethyl) diphosphlne on heating or ultra-violet irradiation reacts only very slightly, while bis(trifluoromethyl)phosphine is essentially inert towards the cyclobutenes. Dimethylamine readily adds to hexafluorobutyne-2 at 20° to give the 1:1 adduct, 2=dimethylamino-3-H-hexafluorobutene-2, the ratio of trans:cis isomers being 6.2:1. The cis isomer Is converted by distillation, but not by heating in a sealed tube, to the trans form. This latter isomer quickly achieves an equilibrium with the cis configuration on exposure to the air; at equilibrium, trans:cis ≈1.6:1. Hexafluorobutyne-2 reacts vigorously at 20° with a trimethylamine-water mixture. The major products of the complex reaction are a bis(hexafluorobutenyl) ether and trans-3-H-heptafluorobutene-2. When the reaction mixture is permitted to reach room temperature only slowly, the ether predominates. In the absence of water a high polymer of the butyne is slowly deposited. Chlorodimethylamine requires heating or ultra-violet irradiation to react with the butyne. The reaction is complex. At 85° (also on irradiation), the major product is the 1:1 adduct (100% cis); at 139°, trans-2-chloro-3-H-hexafluorobutene-2 predominates. Prolonged ultra-violet irradiation of a bis(trifluoromethyl)phosphine-hexafluorobutyne-2 mixture affords a mixture of 1:1 and 2:1 adducts. The expected 1,1,1,4,4,4-hexafluorobut-2-enyl derivatives, are obtained from the acetylene and diethylphosphine, diphenylphosphine and tetraphenyldiphosphine (130°). Tetra-methyldiphosphine gives a low yield of methyldifluorophosphine oxide. Triphenylphosphine vigorously catalyzes the polymerization of the butyne at -78°. ChlorodimethyIphosphine and hexa-fluorobutyne-2 afford trans-3-H-2-chlorohexafluorobutene-2 and trifluorodimethylphosphorane, while chlorodimethyIphosphine sulfide does not react on heating (106°) or ultra-violet irradiation. Tetramethyldiphosphine disulfide and iodine afford a loosely-bound 1:1 complex at 20° in the absence of excess iodine. Trifluoromethyl iodide does not react with the disulfide at 104° and only slightly on prolonged ultra-violet irradiation. DimethyIphosphine readily adds to hexafluoroacetone and 1,1,1-trifluoroaeetone, giving the 2-dimethylphosphino-isopropanols. The reaction with hexafluoroacetone also gives a 1:3 phosphine-acetone adduct. The product from 1,3-diehlorotetrafluoroacetone decomposes violently on reaching room temperature. The reactions of these fluorinated ketones with diphenylphosphine are more complex. The products include a mixture of 1:1 adducts; namely, 2=diphenylphosphino=isopropanols and isopropyldiphenyl-phosphine oxides. The latter probably are a result of an Arbuzov rearrangement of isopropoxydiphenyl-phosphines, Tetramethyl-diphosphine and hexafluoroacetone give a 1:3 adduct along with the 1:3 dimethylphosphine-hexafluoroacetone adduct.

Text

2011-07-16

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http://hdl.handle.net/2429/36036

Chemistry

University of British Columbia

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