Abstract:
A method of cleaning a surface of a substrate is provided. The solvent is selected from a group consisting of hydrochlorofluorocarbons having 3 to 5 carbon atoms and a maximum of two chlorine atoms. The environmental lifetime of the solvent is expected to be less than one year.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a method of cleaning a surface of a substrate using hydrochlorofluorocarbons having 3 to 5 carbon atoms. 
     Vapor degreasing and solvent cleaning with fluorocarbon based solvents have found widespread use in industry for the degreasing and otherwise cleaning of solid surfaces, especially intricate parts and difficult to remove soils. 
     In its simplest form, vapor degreasing or solvent cleaning consists of exposing a room-temperature object to be cleaned to the vapors of a boiling solvent. Vapors condensing on the object provide clean distilled solvent to wash away grease or other contamination. Final evaporation of solvent from the object leaves behind no residue as would be the case where the object is simply washed in liquid solvent. 
     For soils which are difficult to remove, where elevated temperature is necessary to improve the cleaning action of the solvent, or for large volume assembly line operations where the cleaning of metal parts and assemblies must be done efficiently and quickly, the conventional operation of a vapor degreaser consists of immersing the part to be cleaned in a sump of boiling solvent which removes the bulk of the soil, thereafter immersing the part in a sump containing freshly distilled solvent near room temperature, and finally exposing the part to solvent vapors over the boiling sump which condense on the cleaned part. In addition, the part can also be sprayed with distilled solvent before final rinsing. 
     Vapor degreasers suitable in the above-described operations are well known in the art. For example, Sherliker et al. in U.S. Pat. No. 3,085,918 disclose such suitable vapor degreasers comprising a boiling sump, a clean sump, a water separator, and other ancilliary equipment. 
     Cold cleaning is another application where a number of solvents are used. In most cold cleaning applications, the soiled part is either immersed in the fluid or wiped with rags or similar objects soaked in solvents. 
     In cold cleaning applications, the use of the aerosol packaging concept has long been found to be a convenient and cost effective means of dispensing solvents. Aerosol products utilize a propellant gas or mixture of propellant gases, preferably in a liquified gas rather than a compressed gas state, to generate sufficient pressure to expel the active ingredients, i.e. product concentrates such as solvents, from the container upon opening of the aerosol valve. The propellants may be in direct contact with the solvent, as in most conventional aerosol systems, or may be isolated from the solvent, as in barrier-type aerosol systems. 
     Chlorofluorocarbon solvents, such as trichlorotrifluoroethane, have attained widespread use in recent years as effective, nontoxic, and nonflammable agents useful in degreasing applications and other solvent cleaning applications. Trichlorotrifluoroethane has been found to have satisfactory solvent power for greases, oils, waxes and the like. It has therefore found widespread use for cleaning electric motors, compressors, heavy metal parts, delicate precision metal parts, printed circuit boards, gyroscopes, guidance systems, aerospace and missile hardware, aluminum parts and the like. Trichlorotrifluoroethane has two isomers: 1,1,2-trichloro-1,2,2-trifluoroethane (known in the art as CFC-113) and 1,1,1-trichloro-2,2,2-trifluoroethane (known in the art as CFC-113a). CFC-113 has a boiling point of about 47° C. and has been found to have satisfactory solvent power for greases, oils, waxes, and the like. 
     Another commonly used solvent is chloroform (known in the art as HCC-20) which has a boiling point of about 63° C. Perchloroethylene is a commonly used dry cleaning and vapor degreasing solvent which has a boiling point of about 121° C. These compounds are disadvantageous for use as solvents because they are toxic; also, chloroform causes liver damage when inhaled in excess. 
     Although chlorine is known to contribute to the solvency capability of a compound, fully halogenated chlorofluorocarbons and hydrochlorofluorocarbons are suspected of causing environmental problems in connection with the earth&#39;s protective ozone layer. Thus, the art is seeking new compounds which do not contribute to environmental problems but yet provide the solvency properties of CFC-113. 
     Chlorofluorocarbons (CFCs) such as CFC-113 are suspected of causing environmental problems in connection with the ozone layer. Under the Clean Air Act, CFC-113 is being phased-out of production. 
     In response to the need for stratospherically safe materials, substitutes have been developed and continue to be developed. Research Disclosure 14623 (June 1978) reports that 1,1-dichloro-2,2,2-trifluoroethane (known in the art as HCFC-123) is a useful solvent for degreasing and defluxing substrates. In the EPA &#34;Findings of the Chlorofluorocarbon Chemical Substitutes International Committee&#34;, EPA-600/9-88-009 (April 1988), it was reported that HCFC-123 and 1,1-dichloro-1-fluoroethane (known in the art as HCFC-141b) have potential as replacements for CFC-113 as cleaning agents. 
     Commonly assigned U.S. Pat. No. 4,947,881 teaches a method of cleaning using hydrochlorofluoropropanes having 2 chlorine atoms and a difluoromethylene group. European Publication 347,924 published Dec. 27, 1989 teaches hydrochlorofluoropropanes having a difluoromethylene group. International Publication Number WO 90/08814 published Aug. 9, 1990 teaches azeotropes having at least one hydrochlorofluoropropane having a difluoromethylene group. 
     A wide variety of consumer parts is produced on an annual basis in the United States and abroad. Many of these parts have to be cleaned during various manufacturing stages in order to remove undesirable contaminants. These parts are produced in large quantities and as a result, substantial quantities of solvents are used to clean them. It is apparent that the solvent used must be compatible with the material to be cleaned. 
     Other advantages of the invention will become apparent from the following description. 
     SUMMARY OF THE INVENTION 
     The present invention provides a method of cleaning a surface of a substrate which comprises treating the surface with a solvent which is a straight chain or branched hydrochlorofluorocarbon having 3 to 5 carbon atoms. The straight chain hydrochlorofluorocarbons having 3 carbon atoms are listed in Table I below. 
     
                       TABLE I______________________________________Number            Chemical Formula______________________________________HCFC-234ab        CFH.sub.2 CCl.sub.2 CF.sub.3HCFC-234bb        CF.sub.3 CFClCClH.sub.2HCFC-234bc        CFH.sub.2 CFClCF.sub.2 ClHCFC-234fa        CF.sub.2 ClCH.sub.2 CF.sub.2 ClHCFC-234fb        CF.sub.3 CH.sub.2 CFCl.sub.2HCFC-243ec        CF.sub.2 ClCFHCClH.sub.2HCFC-244ba        CFH.sub.2 CFClCF.sub.2 HHCFC-244da        CF.sub.2 HCClHCF.sub.2 HHCFC-244ea        CF.sub.2 HCFHCFClHHCFC-244ec        CFH.sub.2 CFHCF.sub.2 ClHCFC-244fa        CFClHCH.sub.2 CF.sub.3HCFC-244fb        CF.sub.2 HCH.sub.2 CF.sub.2 ClHCFC-252dc        CH.sub.3 CClHCF.sub.2 ClHCFC-253bb        CH.sub.3 CFClCF.sub.2 HHCFC-253ea        CF.sub.2 HCFHCClH.sub.2HCFC-253ec        CH.sub.3 CFHCF.sub.2 ClHCFC-253fa        CF.sub.2 HCH.sub.2 CFClHHCFC-253fc        CFH.sub.2 CH.sub.2 CF.sub.2 ClHCFC-262fa        CF.sub.2 HCH.sub.2 CClH.sub.2HCFC-271b         CH.sub.3 CFClCH.sub.3HCFC-271fb        CH.sub.3 CH.sub.2 CFClH______________________________________ 
    
     Known methods for making fluorinated compounds can be modified in order to form the straight chain hydrochlorofluorocarbons having 3 carbon atoms of the present invention. 
     For example, Haszeldine, Nature 165, 152 (1950) teaches the reaction of trifluoroiodomethane and acetylene to prepare 3,3,3-trifluoro-1-iodopropene which is then dehydroiodinated to form 3,3,3-trifluoropropyne. By using 3,3,3-trifluoropropyne as a starting material, CF 3  CFClCClH 2  (HCFC-234bb) may be prepared as follows. Commercially available trifluoromethyl iodide may be reacted with acetylene to prepare 3,3,3-trifluoro-1-iodopropene which is then dehydroiodinated to form 3,3,3-trifluoropropyne. The 3,3,3-trifluoropropyne may then be reacted with commercially available hydrogen fluoride to form 2,3,3,3-tetrafluoro-1-propene which is then chlorinated to form 1,2-dichloro-2,3,3,3-tetrafluoropropane. 
     E. T. McBee et al., &#34;Fluorinated Derivatives of Propane&#34;, J. of Amer. Chem Soc. 69, 944 (1947) teach a method for the preparation of CClF 2  CHClCH 3  (HCFC-252dc). Commercially available 1,1-dichloropropene is reacted with commercially available commercially available hydrogen chloride to form 1,1,1-trichloropropane. The 1,1,1-trichloropropane is then reacted with commercially available hydrogen fluoride to form 1-chloro-1,1-difluoropropane which is then chlorinated to form 1,2-dichloro-1,1-difluoropropane. 
     CF 2  ClCFHCClH 2  (HCFC-243ec) may be prepared as follows. Commercially available 1,1,3-trichloropropene may be dehydrohalogenated to form 1,3-dichloro-1-propyne. The 1,3-dichloro-1-propyne may then be fluorinated to form 1,3-dichloro-1,2-difluoro-1-propene which may then be reacted with commercially available hydrogen fluoride to form 1,3-dichloro-1,1,2-trifluoropropane. 
     CFH 2  CFClCF 2  H (HCFC-244ba) may be prepared as follows. Commercially available 1,3-difluoro-2-propanol may be dehydrated to form 1,3-difluoro-1-propene which may then be dehydrohalogenated to form 3-fluoro-1-propyne. The 3-fluoro-1-propyne may then be fluorinated, chlorinated, and fluorinated to form 1,1,2,3-tetrafluoro-2-chloropropane. 
     CFH 2  CFHCF 2  Cl (HCFC-244ec) may be prepared as follows. Commercially available 1,1,3-trichloropropene may be fluorinated to form 1,1-dichloro-3-fluoro-1-propene which may then be dehydrohalogenated to form 1-chloro-3-fluoro-1-propyne. The 1-chloro-3-fluoro-1-propyne may then be fluorinated to form 1-chloro-1,2,3-trifluoro-1-propene which may then be reacted with commercially available hydrogen fluoride to form 1-chloro-1,1,2,3-tetrafluoropropane. 
     CFClHCH 2  CF 3  (HCFC-244fa) may be prepared as follows. Commercially available 1,1,3-trichloropropene may be fluorinated to form 1,1,1,2,3-pentafluoropropane. The 1,1,1,2,3-pentafluoropropane may then be dehydrohalogenated to form 1,3,3,3-tetrafluoro-1-propene which may then be reacted with commercially available hydrogen chloride to form 1-chloro-1,3,3,3-tetrafluoropropane. 
     CF 2  HCH 2  CF 2  Cl (HCFC-244fb) may be prepared as follows. Commercially available 2,2,3,3-tetrafluoro-1-propanol may be fluorinated to form 1,1,1,2,2,3-hexafluoropropane which may then be dehydrohalogenated to form 1,3,3-trifluoro-1-propyne. The 1,3,3-trifluoro-1-propyne may then be reacted with commercially available hydrogen chloride to form 1-chloro-1,3,3-trifluoro-1-propene which may then be reacted with commercially available hydrogen fluoride to form 1-chloro-1,1,3,3-tetrafluoropropane. 
     CH 3  CFClCF 2  H (HCFC-253bb) may be prepared as follows. Commercially available 1,2-dibromopropane may be dehydrohalogenated to form propyne. The propyne may then be fluorinated, chlorinated, and fluorinated to form 2-chloro-1,1,2-trifluoropropane. 
     CH 3  CFHCF 2  Cl (HCFC-253ec) may be prepared as follows. Commercially available 1,2-dichloropropane may be dehydrohalogenated to form 1-chloro-1-propene which may then be dehydrogenated to form 1-chloro-1propyne. The 1-chloro-1-propyne may then be reacted with commercially available hydrogen fluoride to form 1-chloro-1-fluoro-1-propene which may then be fluorinated to form 1-chloro-1,1,2-trifluoropropane. 
     The preferred straight chain hydrochlorofluorocarbons having 3 carbon atoms are CF 2  ClCFHCClH 2 , CFH 2  CFClCF 2  H, CFH 2  CFHCF 2  Cl, CFClHCH 2  CF 3 , CF 2  HCH 2  CF 2  Cl, CH 3  CFClCF 2  H, and CH 3  CFHCF 2  Cl. 
     The straight chain hydrochlorofluorocarbons having 4 carbon atoms are listed in Table II below. 
     
                       TABLE II______________________________________Number            Chemical Formula______________________________________HCFC-354lbes      CH.sub.3 CHFCClFCF.sub.2 ClHCFC-354lcd       CH.sub.3 CClHCF.sub.2 CF.sub.2 ClHCFC-354mbd       CH.sub.3 CClHCFClCF.sub.3HCFC-355lcf       CFH.sub.2 CH.sub.2 CF.sub.2 CF.sub.2 ClHCFC-355lec       CH.sub.3 CF.sub.2 CFHCF.sub.2 ClHCFC-355lef       CF.sub.2 HCH.sub.2 CFHCF.sub.2 ClHCFC-355lff       CF.sub.3 CH.sub.2 CH.sub.2 CF.sub.2 ClHCFC-355mbf       CFH.sub.2 CH.sub.2 CFClCF.sub.3HCFC-355mcf       CF.sub.3 CF.sub.2 CH.sub.2 CClH.sub.2HCFC-355mdc       CH.sub.3 CF.sub.2 CClHCF.sub.3HCFC-355mdf       CF.sub.2 HCH.sub.2 CClHCF.sub.3HCFC-355meb       CH.sub.3 CFClCFHCF.sub.3HCFC-355med       CFH.sub.2 CClHCFHCF.sub.3HCFC-355mfb       CFH.sub.2 CFClCH.sub.2 CF.sub.3HCFC-355mfc       CF.sub.3 CH.sub.2 CF.sub.2 CClH.sub.2HCFC-355mfd       CF.sub.2 HCClHCH.sub.2 CF.sub.3HCFC-355mfe       CFClHCFHCH.sub.2 CF.sub.3HCFC-355pcb       CH.sub.3 CFClCF.sub.2 CF.sub.2 HHCFC-355rcc       CH.sub.3 CF.sub.2 CF.sub.2 CFClHHCFC-364med       CH.sub.3 CClHCFHCF.sub.3HCFC-364mff       CFClHCH.sub.2 CH.sub.2 CF.sub.3HCFC-373lef       CH.sub.3 CH.sub.2 CFHCF.sub.2 ClHCFC-373mfd       CH.sub.3 CClHCH.sub.2 CF.sub.3HCFC-373mff       CF.sub.3 CH.sub.2 CH.sub.2 CClH.sub.2HCFC-391rff       CH.sub.3 CH.sub.2 CH.sub.2 CFClHHCFC-391sbf       CH.sub.3 CH.sub.2 CFClCH.sub. 3______________________________________ 
    
     Known methods for making fluorinated compounds can be modified in order to form the straight chain hydrochlorofluorocarbons having 4 carbon atoms of the present invention. 
     For example, R. N. Haszeldine et al., &#34;Addition of Free Radicals to Unsaturated Systems. Part XIII. Direction of Radical Addition to Chloro-1:1-difluoroethylene&#34;, J. of Amer. Chem. Soc., 2193 (1957) teach the reaction of trifluoroiodomethane with chloro-1:1-difluoroethylene to prepare 3-chloro-1:1:1:2:2-pentafluoro-3-iodopropane which is then chlorinated to form 1,1-dichloro-2,2,3,3,3-pentafluoropropane (known in the art as HCFC-225ca). This known method can be modified to form CF 3  CF 2  CH 2  CClH 2  (HCFC-355mcf) as follows. Commercially available perfluoroethyl iodide can be reacted with commercially available ethylene to prepare 1,1,1,2,2-pentafluoro-4-iodobutane which is then chlorinated to form 1,1,1,2,2-pentafluoro-4-chlorobutane. 
     CH 3  CF 2  CFHCF 2  Cl (HCFC-3551ec) may be prepared as follows. Commercially available 1,3-dichloro-2-butene may be fluorinated to form 1-chloro-2,3,3-trifluorobutane which may then be dehydrohalogenated to form 1-chloro-3,3-difluoro-1-butene. The 1-chloro-3,3-difluoro-1-butene may then be dehydrogenated to form 1-chloro-3,3-difluoro-1-propyne which may then be fluorinated to form 1-chloro-1,2,3,3-tetrafluoro-1-butene which may then be reacted with commercially available hydrogen fluoride to form 1-chloro-1,1,2,3,3-pentafluorobutane. 
     CF 3  CH 2  CH 2  CF 2  Cl (HCFC-3551ff) may be prepared as follows. Commercially available 2,3-dichlorohexafluoro-2-butene may be dechlorinated to form hexafluoro-2-butyne. The hexafluoro-2-butyne may be hydrogenated to form 1,1,1,4,4,4-hexafluorobutane which may be chlorinated to form 1-chloro-1,1,4,4,4-pentafluorobutane. 
     CFH 2  CH 2  CFClCF 3  (HCFC-355mbf) may be prepared as follows. Commercially available 1,4-dichloro-2-butyne may be reacted with commercially available hydrogen fluoride to form 1,4-dichloro-2-fluoro-2-butene which may be fluorinated to form 1,2,4-trifluoro-2-butene. The 1,2,4-trifluoro-2-butene may be reacted with commercially available hydrogen chloride to form 2-chloro-1,2,4-trifluorobutane which may be dehydrohalogenated, fluorinated, dehydrohalogenated, and fluorinated to form 2-chloro-1,1,1,2,4-pentafluorobutane. 
     CH 3  CF.sub. CClHCF 3  (HCFC-355mdc) may be prepared as follows. Commercially available 3,4-dichloro-1-butene may be dehydrogenated to form 3,4-dichloro-1-butyne which may be reacted with commercially available hydrogen fluoride to form 1,2-dichloro-3,3-difluorobutane. The 1,2-dichloro-3,3-difluorobutane may be dehydrogenated to form 1,2-dichloro-3,3-difluoro-1-butene which may be reacted with commercially available hydrogen fluoride to form 2-chloro-1,1,3,3-tetrafluorobutane. The 2-chloro -1,1,3,3-tetrafluorobutane may be dehydrogenated to form 2-chloro-1,1,3,3-tetrafluoro-1-butene which may be reacted with commercially available hydrogen fluoride to form 2-chloro-1,1,1,3,3-pentafluorobutane. 
     CH 3  CFClCFHCF 3  (HCFC-355meb) may be prepared as follows. Commercially available 1,3-dichloro-2-butene may be fluorinated to form 2-chloro-2,3,4-trifluorobutane which may be dehydrohalogenated to form 3-chloro-1,3-difluoro-1-butene. The 3-chloro -1,3-difluoro-1-butene may be fluorinated to form 2-chloro-2,3,4,4-tetrafluorobutane which may be dehydrohalogenated to form 3-chloro-1,1,3-trifluoro-1-butene. The 3-chloro-1,1,3-trifluoro-1-butene may be fluorinated to form 2-chloro-2,3,4,4,4-pentafluorobutane. 
     CH 3  CFClCF 2  CF 2  H (HCFC-355pcb) may be prepared as follows. Commercially available 1,3-dichloro-2-butene may be fluorinated to form 2-chloro-2,3,4-trifluorobutane which may be dehydrogenated to form 3-chloro-1,2,3-trifluoro-1-butene. The 3-chloro -1,2,3-trifluoro-1-butene may be fluorinated to form 2-chloro-2,3,3,4,4-pentafluorobutane. 
     CH 3  CF 2  CF 2  CFClH (HCFC-355rcc) may be prepared as follows. Commercially available 1,3-dichloro-2-butene may be fluorinated to form 1-chloro-2,3,3-trifluorobutane which may be dehydrogenated to form 1-chloro-2,3,3-trifluoro-1-butene. The 1-chloro -2,3,3-trifluoro-1-butene may be fluorinated to form 1-chloro-1,2,2,3,3-pentafluorobutane. 
     CH 3  CClHCFHCF 3  (HCFC-364med) may be prepared as follows. Commercially available 1,3-dichloro-2-butene may be reacted with commercially available hydrogen fluoride to form 1,3-dichloro-2-fluorobutane which may be dehydrohalogenated to form 1,3-dichloro-1-butene. The 1,3-dichloro-1-butene may be fluorinated to form 2-chloro-3,4,4-trifluorobutane which may be dehydrohalogenated to form 3-chloro-1,1-difluoro-1-butene. The 3-chloro-1,1-difluoro-1-butene may be fluorinated to form 2-chloro-3,4,4,4-tetrafluorobutane. 
     The preferred straight chain hydrochlorofluorocarbons having 4 carbon atoms are CH 3  CF 2  CFHCF 2  Cl, CF 3  CH 2  CH 2  CF 2  Cl, CFH 2  CH 2  CFClCF 3 , CH 3  CF 2  CClHCF 3 , CH 3  CFClCFHCF 3 , CH 3  CFClCF 2  CF 2  H, CH 3  CF 2  CF 2  CFClH, and CH 3  CClHCFHCF 3 . 
     The branched chain hydrochlorofluorocarbons having 4 carbon atoms are listed in Table III below. 
     
                       TABLE III______________________________________Number            Chemical Formula______________________________________HCFC-345kms       CH.sub.3 C(CF.sub.3)FCFCl.sub.2HCFC-345lls       CH.sub.3 C(CF.sub.2 Cl)FCF.sub.2 ClHCFC-355lms       CH.sub.3 C(CF.sub.3)HCF.sub.2 ClHCFC-355mop       CF.sub.2 HC(CClH.sub.2)HCF.sub.3HCFC-355mps       CH.sub.3 C(CF.sub.2 H)ClCF.sub.3HCFC-355mrs       CH.sub.3 C(CFClH)FCF.sub.3HCFC-373mss       CH.sub.3 C(CH.sub.3)ClCF.sub.3______________________________________ 
    
     Known methods for making fluorinated compounds can be modified in order to form the branched hydrochlorofluorocarbons having 4 carbon atoms of the present invention. 
     CH 3  C(CF 3 )HCF 2  Cl (HCFC-3551ms) may be prepared as follows. Commercially available 1-chloro-2-methylpropene may be fluorinated to form 1-chloro-1,2-difluoro-2-methylpropane which may be dehydrohalogenated to form 1-chloro-1-fluoro-2-methylpropene. The 1-chloro-1-fluoro-2-methylpropene may be fluorinated to form 1-chloro-1,1,2-trifluoro-2-methylpropane which may be dehydrohalogenated to form 3-chloro-3,3-difluoro-2-methylpropene. The 3-chloro-3,3-difluoro-2-methylpropene may be fluorinated to form 1-chloro-1,1,2,3-tetrafluoro-2-methylpropane which may be dehydrogenated to form 3-chloro-1,3,3-trifluoro-2-methylpropene. The 3-chloro-1,3,3-trifluoro-2-methylpropene may be fluorinated to form 1-chloro-1,1,2,3,3-pentafluoro-2-methylpropane which may be dehydrohalogenated to form 3-chloro-1,1,3,3-tetrafluoro-2-methylpropene. The 3-chloro-1,1,3,3-tetrafluoro-2-methylpropene may be fluorinated to form 1-chloro-1,1,3,3,3-pentafluoro-2-methylpropane. 
     CH 3  C(CF 2  H)ClCF 3  (HCFC-355mps) may be prepared as follows. Commercially available 1-chloro-2-methylpropene may be fluorinated to form 1,1,2-trifluoro-2-methylpropane which may be dehydrohalogenated to form 3,3-difluoro-2-methylpropene. The 3,3-difluoro-2-methylpropene may be fluorinated to form 1,1,2,3-tetrafluoro-2-methylpropane which may be dehydrohalogenated to form 1,3,3-trifluoro-2-methylpropene. The 1,3,3-trifluoro-2-methylpropene may be fluorinated to form 1,1,2,3,3-pentafluoro-2-methylpropane which may be dehydrohalogenated to form 1,1,3,3-tetrafluoro-2-methylpropene. The 1,1,3,3-tetrafluoro-2-methylpropene may be chlorinated to form 1,2-dichloro-1,1,4,4-tetrafluoro-2-methylpropane which may be fluorinated to form 2-chloro-1,1,1,3,3-pentafluoro-2-methylpropane. 
     CH 3  C(CFClH)FCF 3  (HCFC-355mrs) may be prepared as follows. Commercially available 1-chloro-2-methylpropene may be fluorinated to form 1-chloro-1,2-difluoro-2-methylpropane which may be dehydrohalogenated to form 3-chloro-3-fluoro-2-methylpropene. The 3-chloro-3-fluoro-2-methylpropene may be fluorinated to form 1-chloro-1,2,3-trifluoro -2-methylpropane which may be dehydrohalogenated to form 3-chloro-1,3-difluoro-2-methylpropene. The 3-chloro -1,3-difluoro-2-methylpropene may be fluorinated to form 1-chloro-1,2,3,3-tetrafluoro-2-methylpropane which may be dehydrohalogenated to form 3-chloro-1,1,3-trifluoro -2-methylpropene. The 3-chloro-1,1,3-trifluoro-2-methylpropene may be fluorinated to form 1-chloro -1,2,3,3,3-pentafluoro-2-methylpropane. 
     The preferred branched hydrochlorofluorocarbons having 4 carbon atoms are CH 3  C(CF 3 )HCF 2  Cl, CH 3  C(CF 2  H)ClCF 3 , and CH 3  C(CFClH)FCF 3 . 
     The branched hydrochlorofluorocarbons having 5 carbon atoms are listed in Table IV below. 
     
                       TABLE IV______________________________________Number           Chemical Formula______________________________________HCFC-356mlfq     CFH.sub.2 CH.sub.2 C(CF.sub.2 Cl)FCF.sub.3HCFC-357lcsp     CF.sub.2 ClCF.sub.2 C(CH.sub.3)FCF.sub.2 HHCFC-357lmps     CH.sub.3 C(CF.sub.3)(CF.sub.2 H)CF.sub.2 ClHCFC-357lsem     CF.sub.3 CFHC(CH.sub.3)FCF.sub.2 ClHCFC-357mbsp     CF.sub.3 CFClC(CH.sub.3)FCF.sub.2 HHCFC-357mcpo     CF.sub.3 CF.sub.2 C(CF.sub.2 H)HCClH.sub.2HCFC-357mcsp     CF.sub.3 CF.sub.2 C(CH.sub.3)ClCF.sub.2 HHCFC-357mcsr     CF.sub.3 CF.sub.2 C(CH.sub.3)FCFClHHCFC-357mlcs     CH.sub.3 CF.sub.2 C(CF.sub.2 Cl)HCF.sub.3HCFC-357mmbs     CH.sub.3 CFClC(CF.sub.3)HCF.sub.3HCFC-357mmel     CF.sub.2 ClCHFC(CH.sub.3)FCF.sub.3HCFC-357mmfo     CH.sub.2 ClCH.sub.2 C(CF.sub.3)FCF.sub.3HCFC-357mmfq     CFH.sub.2 CH.sub.2 C(CF.sub.3)ClCF.sub.3HCFC-357mmfr     CFClHCH.sub.2 C(CF.sub.3)HCF.sub.3HCFC-357mofm     CF.sub.3 CH.sub.2 C(CClH.sub.2)FCF.sub.3HCFC-357msem     CF.sub.3 CFHC(CH.sub.3)ClCF.sub.3HCFC-358mcsr     CF.sub.3 CF.sub.2 C(CH.sub.3)FCClFHHCFC-366mmds     CH.sub.3 CClHC(CF.sub.3)HCF.sub.3HCFC-366mmfo     CClH.sub.2 CH.sub.2 C(CF.sub.3)HCF.sub.3HCFC-375lcss     CF.sub.2 ClCF.sub.2 C(CH.sub.3)FCH.sub.3HCFC-375mbss     CF.sub.3 CFClC(CH.sub.3)FCH.sub.3HCFC-393less     CF.sub.2 ClCFHC(CH.sub.3)HCH.sub.3HCFC-393mdss     CF.sub.3 CClHC(CH.sub.3)HCH.sub. 3HCFC-393sfms     CH.sub.3 CH.sub.2 C(CF.sub.3)ClCH.sub.3HCFC-3-11-1rfss  CFClHCH.sub.2 C(CH.sub.3)HCH.sub.3______________________________________ 
    
     Known methods for making fluorinated compounds can be modified in order to form the branched hydrochlorofluorocarbons having 5 carbon atoms of the present invention. 
     CFH 2  CH 2  C(CF 2  Cl)FCF 3  (HCFC-356mlfq) may be prepared as follows. Commercially available 1,4-dichloro-2-butene may be reacted with commercially available trifluoromethyl iodide to form 1,4-dichloro-2-trifluoromethyl-3-iodobutane which may be dehydrohalogenated to form 1,4-dichloro-3-trifluoromethyl-1-butene. The 1,4-dichloro-3-trifluoromethyl-1-butene may be hydrogenated to form 1,4-dichloro-2-trifluoromethylbutane which may be fluorinated to form 1-chloro-2-trifluoromethyl-4-fluorobutane. The 1-chloro-2-trifluoromethyl-4-fluorobutane may be dehydrogenated to form 1-chloro-2-trifluoromethyl-4-fluoro-1-butene which may be fluorinated to form 1-chloro-2-trifluoromethyl-1,2,4-trifluorobutane. The 1-chloro-2-trifluoromethyl-1,2,4-trifluorobutane may be dehydrohalogenated to form 1-chloro-2-trifluoromethyl-1,4-difluoro-1-butene which may be fluorinated to form 1-chloro-2-trifluoromethyl-1,1,2,4-tetrafluorobutane. 
     CH 3  C(CF 3 )(CF 2  H)CF 2  Cl (HCFC-3571mps) may be prepared as follows. Commercially available 1,1-dichloropropene may be reacted with commercially available trifluoromethyl iodide to form 1,1-dichloro-1-iodo-2-trifluoromethylpropane which may be dehydrohalogenated to form 1,1-dichloro-2-trifluoromethyl-1-propene. The 1,1-dichloro-2-trifluoromethyl-1-propene may be hydrogenated to form 1,1-dichloro-2-trifluoromethylpropane which may be fluorinated to form l,1-difluoro-2-trifluoromethylpropane. The 1,1-difluoro-2-trifluoromethylpropane may be dehydrogenated to form 1,1-difluoro-2-trifluoromethy-1-propene which may be reacted with commercially available trifluoromethyl iodide to form 1,1-difluoro-1-iodo-2,2-trifluoromethylpropane. The 1,1-difluoro-1-iodo-2,2-trifluoromethylpropane may be chlorinated to form 1-chloro-1,1-difluoro-2,2-trifluoromethylpropane which may be hydrogenated to form 1-chloro-1,1-difluoro-2-difluoromethyl-2-trifluoromethylpropane. 
     CF 3  CFHC(CH 3 )FCF 2  Cl (HCFC-3571sem) may be prepared as follows. Commercially available 1,4-dichloro-2-butene may be reacted with commercially available iodomethane to form 1,4-dichloro-3-iodo-2-methylbutane which may be dehydrohalogenated to form 1,4-dichloro-3-methyl-1-butene. The 1,4-dichloro-3-methyl-1-butene may be fluorinated to form 1-chloro-2-methyl-3,4,4-trifluorobutane which may be dehydrohalogenated to form 1,1-difluoro-3-methyl-4-chloro-1-butene. The 1,1-difluoro-3-methyl-4-chloro-1-butene may be fluorinated to form 1-chloro-2-methyl-3,4,4,4-tetrafluorobutane which may be dehydrogenated to form 1-chloro-2-methyl-3,4,4,4-tetrafluoro-1-butene. The 1-chloro-2-methyl-3,4,4,4-tetrafluoro-1-butene may be fluorinated to form 1-chloro-2-methyl-1,2,3,4,4,4-hexafluorobutane which may be dehydrohalogenated to form 1-chloro-2-methyl-1,3,4,4,4-pentafluoro-1-butene. The 1-chloro-2-methyl-1,3,4,4,4-pentafluoro-1-butene may be fluorinated to form 1-chloro-2-methyl-1,1,2,3,4,4,4-heptafluorobutane. 
     CF 3  CFClC(CH 3 )FCF 2  H (HCFC-357mbsp) may be prepared as follows. Commercially available 2,3-dichlorohexafluoro-2-butene may be reacted with commercially available iodomethane to form 2,3-dichloro-3-iodo-2-methyl-1,1,1,4,4,4-hexafluoropropane which may be fluorinated to form 2-methyl-3-chloro-1,1,1,2,3,4,4-heptafluorobutane. The 2-methyl-3-chloro-1,1,1,2,3,4,4-heptafluorobutane may be dehalogenated to form 3-chloro-2-methyl-1,1,3,4,4,4-hexafluoro-1-butene which may be reacted with commercially available hydrogen fluoride to form 3-chloro-2-methyl-1,1,2,3,4,4,4-heptafluorobutane. 
     CF 3  CF 2  C(CH 3 )ClCF 2  H (HCFC-357mcsp) may be prepared as follows. Commercially available 2,3-dichlorohexafluoro-2-butene may be reacted with iodomethane to form 2-methyl-2,3-dichloro-3-iodo-1,1,1,4,4,4-hexafluorobutane which may be fluorinated to form 2-methyl-1,1,1,2,3,3,4,4,4-nonafluorobutane. The 2-methyl-1,1,1,2,3,3,4,4,4-nonafluorobutane may be dehalogenated to form 2-methyl-1,1,3,3,4,4,4-heptafluoro-1-butene which may be reacted with commercially available hydrogen chloride to form 2-chloro-2-methyl-1,1,3,3,4,4,4-heptafluorobutane. 
     CH 3  CF 2  C(CF 2  Cl)HCF 3  (HCFC-357mlcs) may be prepared as follows. Commercially available 1,3-dichloro-2-butene may be reacted with commercially available trifluoromethyl iodide to form 1,3-dichloro-2-trifluoromethyl-3-iodobutane which may be fluorinated to form 1,3,3-trifluoro-2-trifluoromethylbutane. The 1,3,3-trifluoro-2-trifluoromethylbutane may be dehydrogenated to form 1,3,3-trifluoro-2-trifluoromethyl-1-butene which may be fluorinated to form 1,1,2,3,3-pentafluoro-2-trifluoromethylbutane. The 1,1,2,3,3-pentafluoro-2-trifluoromethylbutane may be dehydrohalogenated to form 1,1,3,3-tetrafluoro-2-trifluoromethyl-1-butene which may be reacted with commercially available hydrogen chloride to form 1-chloro-1,1,3,3-tetrafluoro-2-trifluoromethylbutane. 
     CH 3  CFClC(CF 3 )HCF 3  (HCFC-357mmbs) may be prepared as follows. Commercially available 2,3-dichlorohexafluoro-2-butene may be reacted with commercially available trifluoromethyl iodide to form 2,3-dichloro-3-iodo-2-trifluoromethyl-1,1,1,4,4,4-hexafluorobutane which may be fluorinated to form 2-trifluoromethyl-1,1,1,2,3,3,4,4,4-nonafluorobutane. The 2-trifluoromethyl-1,1,1,2,3,3,4,4,4-nonafluorobutane may be dehalogenated to form 3-trifluoromethyl-1,1,2,3,4,4,4-heptafluoro-1-butene which may be hydrogenated to form 2-trifluoromethyl-1,1,1,2,3,4,4-heptafluorobutane. The 2-trifluoromethyl-1,1,1,2,3,4,4-heptafluorobutane may be dehydrohalogenated to form 3-trifluoromethyl-1,2,3,4,4,4-hexafluoro-1-butene which may be hydrogenated to form 3-trifluoromethyl-1,2,3,4,4,4-hexafluorobutane. The 3-trifluoromethyl-1,2,3,4,4,4-hexafluorobutane may be dehydrohalogenated to form 3-trifluoromethyl-2,3,4,4,4-pentafluoro-1-butene which may be reacted with commercially available hydrogen chloride to form 3-chloro-2-trifluoromethyl-1,1,1,2,3-pentafluorobutane. The 3-chloro-2-trifluoromethyl -1,1,1,2,3-pentafluorobutane may be dehalogenated to form 3-chloro-2-trifluoromethyl-1,1,3-trifluoro -1-butene which may be reacted with commercially available hydrogen fluoride to form 3-chloro-2-trifluoromethyl -1,1,1,3-tetrafluorobutane. 
     CF 2  ClCHFC(CH 3 )FCF 3  (HCFC-357mmel) may be prepared as follows. Commercially available 2,3-dichlorohexafluoro-2-butene may be reacted with commercially available iodomethane to form 2,3-dichloro-3-iodo-1,1,1,4,4,4-hexafluoro-2-methylbutane which may be fluorinated to form 2-methylperfluorobutane. The 2-methylperfluorobutane may be dehalogenated to form 1,1,2,3,4,4,4-heptafluoro-3-methyl-1-butene which may be reacted with commercially available hydrogen chloride to form 4-chloro-1,1,1,2,3,4,4-heptafluoro-2-methylbutane. 
     The method of R. N. Haszeldine et al., supra, can be modified to form CH 2  ClCH 2  C(CF 3 )FCF 3  (HCFC-357 mmfo) as follows. Commercially available perfluoroisopropyl iodide may be reacted with commercially available ethylene to prepare 2-trifluoromethyl-1,1,1,2-tetrafluoro-4-iodobutane which may then be chlorinated to form 2-trifluoromethyl-1,1,1,2-tetrafluoro-4-chlorobutane. 
     CFH 2  CH 2  C(CF 3 )ClCF 3  (HCFC-357mmfq) may be prepared as follows. Commercially available 2,3-dichlorohexafluoro-2-butene may be reacted with commercially available trifluoromethyl iodide to form 2,3-dichloro-3-iodo-1,1,1,4,4,4-hexafluoro-2-trifluoromethylbutane which may be fluorinated to form 2-chloro-2-trifluoromethyl-perfluorobutane. The 2-chloro-2-trifluoromethyl-perfluorobutane may be dehalogenated to form 3-chloro-3-trifluoromethyl-1,1,2,4,4,4-hexafluoro-1-butene which may be hydrogenated to form 2-chloro-2-trifluoromethyl-1,1,1,3,4,4-hexafluorobutane. The 2-chloro-2-trifluoromethyl-1,1,1,3,4,4-hexafluorobutane may be fluorinated to form 3-chloro-3-trifluoromethyl-1,4,4,4-tetrafluoro-1-butene which may then be hydrogenated to form 2-chloro-2-trifluoromethyl-1,1,1,4-tetrafluorobutane. 
     CF 3  CFHC(CH 3 )ClCF 3  (HCFC-357msem) may be prepared as follows. Commercially available 2,3-dichlorohexafluoro-2-butene may be reacted with commercially available iodomethane to form 2,3-dichloro-3-iodo-1,1,1,4,4,4-hexafluoro-2-methylbutane which may be chlorinated to form 2,3,3-trichloro-1,1,4,4,4-hexafluoro-2-methylbutane. The 2,3,3-trichloro-1,1,1,4,4,4-hexafluoro-2-methylbutane may be dehalogenated to form 3-chloro-1,1,1,4,4,4-hexafluoro-2-methyl-2-butene which may be reacted with commercially available hydrogen fluoride to form 3-chloro-1,1,1,3,4,4,4-heptafluoro-2-methylbutane. The 3-chloro-1,1,1,3,4,4,4-heptafluoro-2-methylbutane may be dehydrohalogenated to form 1,1,1,4,4,4-hexafluoro-2-methyl-2-butene which may be reacted with commercially available hydrogen chloride to form 2-chloro-1,1,1,3,4,4,4-heptafluoro-2-methylbutane. 
     CF 3  CF 2  C(CH 3 )FCClFH (HCFC-358mcsr) may be prepared as follows. Commercially available 2,3-dichlorohexafluoro-2-butene may be reacted with commercially available trifluoromethyl iodide to form 2,3-dichloro-3-iodo-1,1,1,4,4,4-hexafluoro-2-methylbutane which may be fluorinated to form 2-methylperfluorobutane. The 2-methyl-perfluorobutane may be dehalogenated to form 2-methyl-perfluoro-1-butene which may be reacted with commercially available hydrogen fluoride to form 1,1,2,3,3,4,4,4-octafluoro-2-methylbutane. The 1,1,2,3,3,4,4,4-octafluoro-2-methylbutane may be dehalogenated to form 1,3,3,4,4,4-hexafluoro-2-methyl-1-butene which may be chlorinated to form 1,2-dichloro-1,3,3,4,4,4-hexafluoro-2-methylbutane. The 1,2-dichloro-1,3,3,4,4,4-hexafluoro -2-methylbutane may be dehydrohalogenated to form 1-chloro-1,3,3,4,4,4-hexafluoro-2-methyl-1-butene which may be reacted with commercially available hydrogen fluoride to form 1-chloro-1,2,3,3,4,4,4-heptafluoro-2-methylbutane. 
     CH 3  CClHC(CF 3 )HCF 3  (HCFC-366mmds) may be prepared as follows. Commercially available 2,3-dichlorohexafluoro-2-butene may be reacted with trifluoromethyl iodide to form 2,3-dichloro-3-iodo-1,1,1,4,4,4 -hexafluoro-2-trifluoromethylbutane which may be chlorinated to form 3-iodo-1,1,1,4,4,4-hexafluoro-2-methyl-2-butene. The 3-iodo-1,1,1,4,4,4-hexafluoro-2-trifluoromethyl-2-butene may be hydrogenated to form 3-iodo-1,1,1,4,4,4-hexafluoro-2-trifluoromethylbutane which may be dehydrohalogenated to form 2-iodo-1,1,4,4,4-pentafluoro-3-trifluoromethyl-1-butene. The 2-iodo-1,1,4,4,4-pentafluoro-3-trifluoromethyl-1-butene may be hydrogenated to form 3-iodo-1,1,1,4,4-pentafluoro-2-trifluoromethylbutane which may be chlorinated to form 3-chloro-1,1,1,4,4-pentafluoro-2-trifluoromethylbutane. The 3-chloro-1,1,1,4,4-pentafluoro-2-trifluoromethylbutane may be dehydrohalogenated to form 2-chloro-1,4,4,4-tetrafluoro-3-trifluoromethyl-1-butene which may be hydrogenated to form 3-chloro-1,1,1,4-tetrafluoro-2-trifluoromethylbutane. The 3-chloro-1,1,1,4-tetrafluoro-2-trifluoromethylbutane may be dehydrohalogenated to form 2-chloro-4,4,4-trifluoro-3-trifluoromethyl-1-butene which may be hydrogenated to form 3-chloro-1,1,1-trifluoro-2-trifluoromethylbutane. 
     The preferred branched hydrochlorofluorocarbons having 5 carbon atoms are CFH 2  CH 2  C(CF 2  Cl)FCF 3 , CH 3  C(CF 3 )(CF 2  H)CF 2  Cl, CF 3  CFHC(CH 3 )FCF 2  Cl, CF 3  CFClC(CH 3 )FCF 2  H, CF 3  CF 2  C(CH 3 )ClCF 2  H, CH 3  CF 2  C(CF 2  Cl)HCF 3 , CH 3  CFClC(CF 3 )HCF 3 , CF 2  ClCHFC(CH 3 )FCF 3 , CH 2  ClCH 2  C(CF 3 )FCF 3 , CFH 2  CH 2  C(CF 3 )ClCF 3 , CF 3  CFHC(CH 3 )ClCF 3 , CF 3  CF 2  C(CH 3 )FCClFH, and CH 3  CClHC(CF 3 )HCF 3 . 
     The present method is advantageous because the solvents have low atmospheric lifetimes. 
     Other advantages of the invention will become apparent from the following description. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Known solvents may be blended with the solvents of the present method. Examples of useful known solvents are listed in Table V below. 
     
                       TABLE V______________________________________Number             Chemical Formula______________________________________HCFC-234cc         CF.sub.2 ClCF.sub.2 CClH.sub.2HCFC-234cd         CH.sub.2 FCF.sub.2 CFCl.sub.2HCFC-244ca         CF.sub.2 HCF.sub.2 CClH.sub.2HCFC-244cb         CFH.sub.2 CF.sub.2 CFClHHCFC-253ca         CFH.sub.2 CF.sub.2 CClH.sub.2HCFC-253cb         CH.sub.3 CF.sub.2 CFClH______________________________________ 
    
     HCFC-234cc may be formed by any known method such as the reaction of 1,1,1,2,2,3-hexachloropropane with antimony pentachloride and hydrogen fluoride at 100° C. HCFC-234cd may be formed by any known method such as the reaction of 1,1,1-trichloro-2,2,3-trifluoropropane with antimony pentachloride and hydrogen fluoride at 120° C. 
     HCFC-244ca may be formed by any known method such as the reaction of 1,1,2,2,3-pentachloropropane with antimony pentachloride and hydrogen fluoride at 100° C. HCFC-244cb may be formed by any known method such as the reaction of 1-chloro-1,1,2,2-tetrafluoropropane with cesium fluoride and tetrabutylammonium bromide at 150° C. 
     HCFC-253ca may be formed by any known method such as the reaction of 1,2,3-trichloro-2-fluoropropane with niobium pentachloride and hydrogen fluoride at 100° C. HCFC-253cb may be formed by any known method such as the reaction of 1,1,2,2-tetrachloropropane with tantalum pentafluoride and hydrogen fluoride at 130° C. 
     The present method removes most contaminants from the surface of a substrate. For example, the present method removes organic contaminants such as mineral oils from the surface of a substrate. Under the term &#34;mineral oils&#34;, both petroleum-based and petroleum-derived oils are included. Lubricants such as engine oil, machine oil, and cutting oil are examples of petroleum-derived oils. 
     The present method also removes water from surface of a substrate. The method may be used in the single-stage or multi-stage drying of objects. 
     The present method may be used to clean the surface of inorganic substrates and some organic substrates. Examples of inorganic substrates include metallic substrates, ceramic substrates, and glass substrates. Examples of organic substrates include polymeric substrates such as polycarbonate, polystyrene, and acrylonitrile-butadiene-styrene. The method also may be used to clean the surface of natural fabrics such as cotton, silk, fur, suede, leather, linen, and wool. The method also may be used to clean the surface of synthetic fabrics such as polyester, rayon, acrylics, nylon, and blends thereof, and blends of synthetic and natural fabrics. It should also be understood that composites of the foregoing materials may be cleaned by the present method. 
     The present method may be used in vapor degreasing, solvent cleaning, cold cleaning, dewatering, and dry cleaning. In these uses, the object to be cleaned is immersed in one or more stages in the liquid and/or vaporized solvent or is sprayed with the liquid solvent. Elevated temperatures, ultrasonic energy, and/or agitation may be used to intensify the cleaning effect. 
    
    
     The present invention is more fully illustrated by the following non-limiting Examples. 
     EXAMPLES 1-85 
     Each solvent listed in Tables I through IV are added to mineral oil in a weight ratio of 50:50 at 27° C. Each solvent is miscible in the mineral oil. 
     Having described the invention in detail and by reference to preferred embodiments thereof, it will be apparent that modifications and variations are possible without departing from the scope of the invention defined in the appended claims.