Freon nomenclature

The following appeared in sci.chem and is reposted here without the
knowledge or consent of the authors.

  From: tgcpwd [at] rw8__urc__tue__nl (Wim van Dorst)
  Newsgroups: sci.chem
  Subject: Freon nomenclature
  Message-ID: <5509 [at] tuegate__tue__nl>
  Date: 21 Sep 92 07:35:11 GMT

  In article <1992Sep18.130342.15691 [at] husc3__harvard__edu>
     habersch [at] husc10__harvard__edu (Oren Haber-Schaim) writes:
  >>What is the numerical identification system that encodes the
  >>formula for Freons?   I saw it long ago....

  For the formula C_cH_hCl_{4c-h-f}F_f the Refrigerant coding is
  {c-1}{h+1}f, for example
  CFC-12 (_the_ freon) stands for CCl_2F_2
  HCFC-22 (current replacement of 12) stands for CHClF_2
  and C_2H_2F_4 is coded as HFC-134 (HFC-134a in is asymmetrical form)

  >>I have a bottle of "Freon TP35" that is supposed to be Freon TF,
  >>for a cleaning purpose limited to Freon TF.   I want to determine
  >>if the "P" is a misprint for "F" by decoding the "35" and seeing if
  >>it corresponds to trichlorotrifluoroethane, which is plain
  >>Freon TF as I recall.

  In the above scheme 35 is chemical nonsense, so probably it not a code
  in the official refrigerant code, as given in the Montreal Protocol
  which regulates the reduction of CFCs in the near future. The TP35 code
  doesn't ring a bell with me, though I am investigating CFCs. It may well
  be a trademark like name, as is Freon (Freon is a registered trademark
  by E.I. du Pont de Nemours, as far as I recall).

  trichlorotrifluoroethane would be coded as CFC-113, and is one of the
  current CFCs in use. It is to phase out asap by Montreal Protocol.

  Met vriendelijke groeten, Wim van Dorst

                                  ***
                  Conservation DistList Instance 6:22
               Distributed: Thursday, September 24, 1992
                        Message Id: cdl-6-22-006
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