Organic compounds -- part of the class 532-570 series – Organic compounds – Halogen containing
Patent
1997-10-17
1999-09-28
Siegel, Alan
Organic compounds -- part of the class 532-570 series
Organic compounds
Halogen containing
570111, 570119, 570121, C07C 1742
Patent
active
059591650
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to methods and compositions for inhibiting decomposition of 1,1,1,2,3,3-hexafluoropropane (hereinafter referred to as HFC236ea) and 1,1,1,3,3-pentafluoropropane (hereinafter referred to as HFC245fa). In particular, the invention relates to methods for stabilizing HFC236ea and HFC245fa useful as foaming agents for synthetic resins and inhibiting decomposition thereof, and to decomposition inhibiting compositions preferably usable for said methods.
PRIOR ART
Hydrocarbon halides completely substituted with fluorine or chlorine (hereinafter referred to as fleons) had been widely used as refrigerants, solvents, foaming agents or the like because of their high performance. However, use and production of fleons have been limited since they were found to destroy the ozone layer of the atmosphere of the earth. Accordingly, it is essential to develop novel compounds which can substitute for fleons. Favorable substitutes for fleons include hydrogen-containing hydrocarbon halides (hereinafter referred to as hydrogen-containing fleons) which involves no or low risk of destroying the ozone layer.
Hydrogen-containing fleons so far proposed as foaming agents include 1,1-dichloro-2,2,2-trifluoroethane (HFC-123), 1,1-dichloro-1-fluoroethane (HFC-141b) and the like. However, these compounds, which contain a chlorine atom in the molecule, still have the property of destroying the ozone layer, although the influence is small. In view of these facts, it is necessary to develop a novel foaming agent free from the risk of destroying the ozone layer.
Japanese Unexamined Patent Publication No. 239251/1993 proposes use of HFC236ea and HFC245fa, which are hydrocarbon fluorides free from the risk of destroying the ozone layer, as foaming agents. Hydrogen-containing hydrocarbon halides free from chlorine atoms, although having higher stability than hydrocarbon halides containing chlorine and hydrogen, gradually decompose during storage, transport, etc., giving adverse effects on the production of foamed products.
Japanese Unexamined Patent Publication No. 239251/1993, however, merely suggests use of stabilizers, and does not specify the kinds thereof. It is necessary for the stabilizer to have decomposition inhibiting effects under various conditions. In view of this matter, full consideration should be given to the selection of the stabilizer.
OBJECT OF THE INVENTION
An object of the present invention is to provide a decomposition inhibiting composition which keeps HFC236ea and HFC245fa stable not only during storage but also during the long-term use of the foamed product (such as urethane foam).
DISCLOSURE OF THE INVENTION
The present inventors conducted extensive research in view of the present state of the art as described above, and found that HFC236ea and HFC245fa are stabilized and prevented from being decomposed when mixed with a mixture of a nitro compound and an aromatic hydrocarbon and/or an alicyclic unsaturated hydrocarbon, the mixture optionally containing other specific compound.
They also found that, according to the above method, decomposition of HFC236ea and HFC245fa can be inhibited for a long period under various conditions during storage, transport or use as foaming agents, irrespective of the presence of an alcoholic hydroxyl group-containing compound which promotes decomposition of HFC236ea and HFC245fa. Further, decomposition of HFC236ea and HFC245fa as remaining in the foamed product can be inhibited by the above method. The present invention has been accomplished based on the above novel findings.
The present invention provides a method and composition for inhibiting decomposition of HFC236ea and HFC245fa.
The present invention provides a method for inhibiting decomposition of HFC236ea and HFC245fa, the method comprising adding, to HFC236ea or HFC245fa, (1) at least one nitro compound and (2) at least one member selected from the group consisting of an aromatic hydrocarbon and an alicyclic unsaturated hydrocarbon, optionally together with (3) at le
REFERENCES:
patent: 3085116 (1963-04-01), Kvalnes
patent: 3465052 (1969-09-01), Okamura et al.
patent: 5124503 (1992-06-01), Li
Ide Satoshi
Tsuchiya Tatsumi
Daikin Industries Ltd.
Siegel Alan
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