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The acrylic ester F2CCFCO2CD3 is prepared from a mixture of difluorotetrachloroethanes CFCI2CFCI2 and CF2CICCI. The dehalogenation of these Freons, followed by the addition of CFCI3 by means of AICI3 leads to a mixture of chlorofluoropropanes. The hydrolysis with oleum gives the acid chlorides which are then esterified by CD3OD. The dehalogenation of the mixture by the zinc stirred in oxalic acid enables isolation of the expected ester by distillation. This compound, the refractive index of which n20D=1.3667 does not show a major absorption in the near infra-red between 0.6 and 1.4 μm. Thus the corresponding polymer is likely to provide a good material for the core of optical fibers.
- Boutevin,Pietrasanta,Rousseau,Bosc
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p. 151 - 169
(2007/10/02)
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- Synthesis of > and Some Chlorofluoropropenes
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The starting substances C3Cl5F3 (1) and C3Cl4F4 (2) prepared earlier by the addition of CCl3F with CClF=CClF and/or CF2=CClF were utilized for the synthesis of chlorofluoropropenes by means of fluorination, reduction of C-Cl bonds in halogenopropanes, and final dehalogenation, all the reactions being performed at atmospheric pressure.The reaction conditions permit laboratory scale production.The contents of the isomeric admixtures in the resultant products were determined by NMR spectroscopy.The starting halogenopropanes 1, 2 represent mixtures of isomers, but in course of the individual synthetic steps the content of the main isomer was generally increased.In comparison with previously used syntheses, our procedure proves advantageous for the synthesis of "perfluoroallylchloride" (9a, isomer purity 95percent).Using this procedure a number of halogenopropanes were prepared and dechlorinated to give the corresponding halogenopropenes (isomer purity percent): CClF2-CClF-CCl2F (2a, 87), CF3-CClF-CCl3 (2b, 78), CClF2-CClF-CClF2 (3a, 87), CF3-CClF-CCl2F (3b, 90), CF3-CClF-CHCl2 (5a, 90), CF3-CClF-CHClF (6a, 73), CClF2-CF=CClF (8a, 93), CF3-CF=CCl2 (8b, 84), 9a, CF3-CF=CClF (9b, 86) and CF3-CF=CHCl (11a, 84).The minor isomers in substance 2 yielded products which were isolated after being combined from several preparations: CClF2-CF2-CHCl2 (5b, 84); CClF2-CF=CHCl (10a, 98), which by addition of chlorine yielded CClF2-CClF-CHCl2 (4a, 95).The NMR spectra of all the major and minor products, excluding perhalogenopropanes, are listed.
- Paleta, Oldrich,Kvicala, Jaroslav,Guenter, Jaroslav,Dedek, Vaclav
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p. 920 - 924
(2007/10/02)
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