(US5458798-A)      Azeotropic compsn. comprises 1,1,1,2-tetrafluoroethane (at least about 97 wt%) and 2-methylbutane (up to about 3 wt%), at about 18.7 C and 79.5 psi. Analogous azeotropes contain 1,1,2,2-tetrafluoroethane (at least 93 or 94 wt%) and 2-methyl- -butane or n-pentane. Pref. one or more additives are included, e.g. lubricants, corrosion inhibitors, stabilisers, dyes, etc.    USE -   The prods. are refrigerants, cleaning agents, fire extinguishing agents, distending agents for foams, gaseous dielectrics, polymerisation solvents and aerosol carriers for lubricants, corrosion inhibitors, stabilisers, dyes, etc.    ADVANTAGE -   The prods. are non-inflammable and almost free from ozone depletion properties.    (JP8506581-W)      Non-flammable azeotrope or azeotrope like compsn. comprises: at least one fluorine contg. molecule selected from HFC-134a, HFC-134, HFC-23, HFC-236 ea and HFC-236 fa; and 0-6 wt.% of at least one hydrocarbon; at a temp. and pressure sufficient to cause formation of the compsn. The atmospheric pressure b.pt. of the fluorine contg. molecule and the hydrocarbon differ by at least 37 deg.    USE/ADVANTAGE -   The compsns. may be used as refrigerants (claimed), cleaning agents, expansion agents, for polyolefins, and polyurethanes, aerosol propellants, heat transfer media, gaseous dielectrics, fire extinguishing agents, power cycle working fluids, polymerisation media, particulate removal fluids, carrier fluids, buffing abrasive agents, and displacement drying agents. The formation of an azeotropic or azeotrope like compsn. can lower or eliminate the flammability of mixts. contg. a hydrocarbon and a fluorinated molecule. The heat transfer coefft. of refrigerants such as hydrofluorocarbons or hydrochlorofluorocarbons is increased by 10-50% in heat transfer equipment having enhanced substances by addn. of a small amt. of a hydrocarbon.    (EP1028152-A2)      Non-flammable azeotrope or azeotrope like compsn. comprises: at least one fluorine contg. molecule selected from HFC-134a, HFC-134, HFC-23, HFC-236 ea and HFC-236 fa; and 0-6 wt.% of at least one hydrocarbon; at a temp. and pressure sufficient to cause formation of the compsn. The atmospheric pressure b.pt. of the fluorine contg. molecule and the hydrocarbon differ by at least 37 deg.    USE/ADVANTAGE -   The compsns. may be used as refrigerants (claimed), cleaning agents, expansion agents, for polyolefins, and polyurethanes, aerosol propellants, heat transfer media, gaseous dielectrics, fire extinguishing agents, power cycle working fluids, polymerisation media, particulate removal fluids, carrier fluids, buffing abrasive agents, and displacement drying agents. The formation of an azeotropic or azeotrope like compsn. can lower or eliminate the flammability of mixts. contg. a hydrocarbon and a fluorinated molecule. The heat transfer coefft. of refrigerants such as hydrofluorocarbons or hydrochlorofluorocarbons is increased by 10-50% in heat transfer equipment having enhanced substances by addn. of a small amt. of a hydrocarbon.