WO1991019019A1

WO1991019019A1 - Azeotrope-like compositions of dichloropentafluoropropane, methanol and 1,2-dichloroethylene

Info

Publication number: WO1991019019A1
Application number: PCT/US1991/002561
Authority: WO
Inventors: Hillel Magid; David Paul Wilson; Dennis M. Lavery; Richard M. Hollister
Original assignee: Allied-Signal Inc.
Priority date: 1990-06-06
Filing date: 1991-04-15
Publication date: 1991-12-12
Also published as: AU7781891A

Abstract

Novel azeotrope-like compositions comprising dichloropentafluoropropane, methanol and 1,2-dichloroethylene which are useful in a variety of industrial cleaning applications including cold cleaning and defluxing of printed circuit boards.

Description

AZEOTROPE-LIKE COMPOSITIONS OF DICHLOROPENTAFLUOROPROPANE, METHANOL.AND 1.2-DICHLOROETHYLE^*N£

Field of the Invention

This invention relates to azeotrope-like mixtures of dichloropentafluoropropane, methanol and 1,2-dichloroethylene. These mixtures are useful in a variety of vapor degreasing, cold cleaning, and solvent cleaning applications including defluxing and dry cleaning.

CROSS-REFERENCE TO RELATED APPLICATIONS

Co-pending, commonly assigned patent application serial no.: 418,008, filed October 6, 1989, discloses azeotrope-like mixtures of 1,1- dichloro-2,2,3,3,3-pentafluoropropane and alkanol having 1 to 3 carbon atoms.

Co-pending, commonly assigned patent application serial no.: 417,983, filed October 6, 1989, discloses azeotrope-like mixtures of 1,3- dichloro-1,1,2,2,3-pentafluoropropane and alkanol having 1 to 3 carbon atoms.

Co-pending, commonly assigned patent application serial no.: , filed , discloses azeotrope-like compositions of dichloro¬ pentafluoropropane and an alkanol having 1 to 4 carbon atoms.

Co-pending, commonly assigned patent application serial no.: 418,050, filed October 6, 1989, discloses azeotrope-like mixtures of 1,l-dichloro-2,2,3,3,3-pentafluoropropane and 1,2-dichloroethylene.

Co-pending, commonly assigned patent application serial no.: 417,452, filed December 6, 1989, discloses azeotrope-like mixtures of 1,3- dichloro-1,1,2,2,3-pentafluoropropane and 1,2-dichloroethylene.

BACKGROUND OF THE INVENTION

Fluorocarbon based solvents have been used extensively 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 leaves the object free of residue. This is contrasted with liquid solvents which leave deposits on the object after rinsing.

A vapor degreaser is used for difficult to remove soils 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. 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. Patent 3,085,918 disclose such suitable vapor degreasers comprising a boiling sump, a clean sump, a water separator, and other ancillary 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 cloths soaked in solvents and allowed to air dry.

Recently, non-toxic, non-flammable fluoro- carbon solvents like trichlorotrifluoroethane, have been used extensively in degreasing applications and other solvent cleaning applications. Trichloro¬ trifluoroethane 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, etc.

The art has looked towards azeotropic compositions having fluorocarbon components because the fluorocarbon components contribute additionally desired characteristics, like polar functionality, increased solvency power, and stabilizers. Azeotropic compositions are desired because they do not fractionate upon boiling. This behavior is c desirable because in the previously described vapor degreasing equipment with which these solvents are employed, redistilled material is generated for final rinse-cleaning. Thus, the vapor degreasing system acts as a rtill. Therefore, unless the solvent

■_jQ composition is essentially constant boiling, fractionation will occur and undesirable solvent distribution may act to upset the cleaning and safety of processing. Preferential evaporation of the more volatile components of the solvent mixtures, which

, _- would be the case if they were not an azeotrope or azeotrope-like, would result in mixtures with changed compositions which may have less desirable properties, such as lower solvency towards soils, less inertness towards metal, plastic or elastomer components, and increased flammability and toxicity.

20

The art is continually seeking new fluoro¬ carbon based azeotropic mixtures or azeotrope-like mixtures which offer alternatives for new and special applications for vapor degreasing and other cleaning

25 applications. Currently, fluorocarbon-based azeotrope-like mixtures are of particular interest because they are considered to be stratospherically safe substitutes for presently used fully halogenated chlorofluorocarbons. The latter have been implicated

30 in causing environmental problems associated with the depletion of the earth's protective ozone layer. Mathematical models have substantiated that hydrochlorofluorocarbons, like dichloropentafluoro¬ propane, have a much lower ozone depletion potential

35 and global warming potential than the fully halogenated species. Accordingly, it is an object of this invention to provide novel environmentally acceptable azeotrope- like compositions based on dichloropentafluoro- c propane, methanol and 1,2-dichloroethylene which are useful in a variety of industrial cleaning applications.

It is another object of this invention to

10 provide azeotrope-like compositions which are liquid at room temperature and will not fractionate under conditions of use.

Other objects and advantages of the invention , - will become apparent from the following description.

SUMMARY OF THE INVENTION

The invention relates to novel azeotrope-like compositions which are useful in a variety of

20 industrial cleaning applications. Specifically, the invention relates to compositions of dichloropenta- fluoropropane, methanol and 1,2-dichloroethylene which are essentially constant boiling, environment¬ ally acceptable and which remain liquid at room

25 temperature.

DETAILED DESCRIPTION OF THE INVENTION

In accordance with the invention, novel

30 azeotrope-like compositions have been discovered consisting essentially of from about 55 to about 92.5 weight percent dichloropentafluoropropane, from about 3 to about 18 weight percent methanol and from about 4.5 to about 27 weight percent 1,2-dichloroethylene

35 which boil at about 47.5°C ± about 3.0°C at 760 mm Hg. Dichloropentafluoropropane exists in nine isomeric forms: (1) 2,2-dichloro-l,1,1,3,3- pentafluoropropane (HCFC-225a) ; (2) 1,2-dichloro- 1,2,3,3,3-pentafluoropropane (HCFC-225ba) ; (3) 1,2-dichloro-l,1,2,3,3-pentafluoropropane (HCFC-225bb) ; (4) 1,l-dichloro-2,2,3,3,3- pentafluoropropane (HCFC-225ca) ; (5) 1,3- dichloro-1,1,2,2,3-pentafluoropropane (HCFC-225cb) ; (6) 1,1-dichloro-1,2,2,3,3-pentafluoropropane (HCFC-225cc) ; (7) 1,2-dichloro-l,1,3,3,3-pentafluoro¬ propane (HCFC-225d) ; (8) 1,3-dichloro-l,1,2,3,3- pentafluoropropane (HCFC-225ea) ; and (9) 1,1- dichloro-1,2,3,3,3-pentafluoropropane (HCFC-225eb) . For purposes of this invention, dichloropentafluoro¬ propane will refer to any of the isomers or admixtures of the isomers in any proportion. The 1,l-dichloro-2,2,3,3,3-pentafluoropropane isomer is the preferred isomer.

The 1,2-dichloroethylene component of the invention exists in two isomeric forms, cis-1,2-dichloroethylene and trans-1,2-dichloro¬ ethylene. For purposes of this invention, 1,2-dichloroethylene will refer to either isomer or admixtures of the isomers in any proportion. The cis-1,2-dichloroethylene isomer, however, is the preferred isomer.

The dichloropentafluoropropane component of the invention has good solvent properties. Methanol and 1,2-dichloroethylene too, are good solvents. Methanol dissolves polar organic materials and amine hydrochlorides while 1,2-dichloroethylene enhances the solubility of oils. Thus, when these components are combined in effective amounts, an efficient azeotropic solvent results. In a preferred embodiment, the azeotrope-like compositions of the invention consist essentially of from about 67 to about 91 weight percent dichloro- pentafluoropropane, from about 3 to about 13 weight percent methanol and from about 6 to about 20 weight percent 1,2-dichloroethylene.

In a more preferred embodiment, the azeotrope-like compositions of the invention consist essentially of from about 70 to about 88 weight percent dichloropentafluoropropane, from about 3 to about 13 weight percent methanol and from about 9 to about 17 weight percent 1,2-dichloroethylene.

In a still more preferred embodiment, the azeotrope-like compositions of the invention consist essentially of from about 75 to about 87 weight percent dichloropentafluoropropane, from about 4 to about 8 weight percent methanol and from about 9 to about 17 weight percent 1,2-dichloroethylene.

When the dichloropentafluoropropane component is 1,l-dichloro-2,2,3,3,3-pentafluoropropane (225ca), the azeotrope-like compositions of the invention consist essentially of from about 67 to about.91 weight percent 1,l-dichloro-2,2,3,3,3-pentafluoro¬ propane, from about 3 to about 13 weight percent methanol and from about 6 to about 20 weight percent 1,2-dichloroethylene and boil at about 45.2°C ± about 1.0°C and preferably ± about 0.7°C at 760 mm Hg.

In a preferred embodiment of the invention utilizing 225ca, the azeotrope-like compositions consist essentially of from about 70 to about 88 weight percent 1,l-dichloro-2,2,3,3,3-pentafluoro- propane, from about 3 to about 13 weight percent methanol and from about 9 to about 17 weight percent 1,2-dichloroethylene.

In a more preferred embodiment of the invention utilizing 225ca, the azeotrope-like compositions consist essentially of from about 74 to about 87 weight percent 1,l-dichloro-2,2,3,3,3-penta- fluoropropane, from about 4 to about 9 weight percent methanol and from about 9 to about 17 weight percent 1,2-dichloroethylene.

In a still more preferred embodiment of the invention utilizing 225ca, the azeotrope-like compositions consist essentially of from about 76 to about 87 weight percent 1,l-dichloro-2,2,3,3,3-penta- fluoropropane, from about 4 to about 8 weight percent methanol, and from about 9 to about 16 weight percent 1,2-dichloroethylene.

The precise or true azeotrope compositions have not been determined but have been ascertained to be within the indicated ranges. Regardless of where the true azeotropes lie, all compositions within the indicated ranges, as well as certain compositions outside the indicated ranges, are azeotrope-like, as defined more particularly below.

From fundamental principles, the thermodynamic state of a fluid is defined by four variables: pressure, temperature, liquid composition and vapor composition, or P-T-X-Y, respectively. An azeotrope is a unique characteristic of a system of two or more components where X and Y are equal at a stated P and T. In practice, this means that the components of a ixture cannot be separated during distillation, and therefore are useful in vapor phase solvent cleaning as described above.

For the purpose of this discussion, by azeotrope-like composition is intended to mean that the composition behaves like a true azeotrope in terms of its constant-boiling characteristics or

10 tendency not to fractionate upon boiling or evaporation. Such composition may or may not be a true azeotrope. Thus, in such compositions, the composition of the vapor formed during boiling or evaporation is identical or substantially identical , _- to the original liquid composition. Hence, during boiling or evaporation, the liquid composition, if it changes at all, changes only minimally. This is contrasted with non-azeotrope-like compositions in which the liquid composition changes substantially during boiling or evaporation.

20

Thus, one way to determine whether a candidate mixture is "azeotrope-like" within the meaning of this invention, is to distill a sample thereof under

25 conditions (i.e. resolution - number of plates) which would be expected to separate the mixture into its separate components. If the mixture is non- azeotropic or non-azeotrope-like, the mixture will fractionate, i.e., separate into its various components with the lowest boiling component

30 distilling off first, and so on. If the mixture is azeotrope-like, some finite amount of a first distillation cut will be obtained which contains all of the mixture components and which is constant boiling or behaves as a single substance. This

35 phenomenon cannot occur if the mixture is not azeotrope-like, i.e., it is not part of an azeotropic system. If the degree of fractionation of the candidate mixture is unduly great, then a composition closer to the true azeotrope must be selected to minimize fractionation. Of course, upon distillation of an azeotrope-like composition such as in a vapor degreaser, the true azeotrope will form and tend to concentrate.

It follows from the above that another characteristic of azeotrope-like compositions is that there is a range of compositions containing the same components in varying proportions which are azeotrope- like. All such compositions are intended to be covered by the term azeotrope-like as used herein. As an example, it is well known that at different pressures, the composition of a given azeotrope will vary at least slightly as does the boiling point of the composition. Thus, an azeotrope of A and B represents a unique type of relationship having a variable composition depending on temperature and/or pressure. Accordingly, another way of defining azeotrope-like within the meaning of the invention is to state that such mixtures boil within about ± 3.0°C (at 760 mm Hg) of the 47.5°C boiling point disclosed herein. As is readily understood by persons skilled in the art, the boiling point of the azeotrope will vary with the pressure.

In the process embodiment of the invention, the azeotrope-like compositions of the invention may be used to clean solid surfaces by treating said surfaces with said compositions in any manner well known in the art such as by dipping or spraying or use of conventional degreasing apparatus. As stated above, the azeotrope-like compositions of the invention are useful-as solvents for a variety of cleaning applications including vapor degreasing, defluxing, cold cleaning, dry cleaning, dewatering, decontamination, spot cleaning, aerosol propelled rework, extraction, particle removal, and surfactant cleaning applications. These azeotrope-like compositions are also useful as

10 blowing agents, Rankine cycle and absorption refrigerants, and power fluids.

The dichloropentafluoropropane, methanol, and 1,2-dichloroethylene components of the invention are -, _- known materials. Preferably, they should be used in sufficiently high purity so as to avoid the introduction of adverse influences upon the solvents or constant boiling properties of the system. Commercially available methanol and 1,2-dichloro¬ ethylene may be used in the present invention. Most

20 of the dichloropentafluoropropane isomers, however, are not available in commercial quantities, therefore, until such time as they become commercially available, they may be prepared by following the organic syntheses disclosed herein.

25 For example, 1,l-dichloro-2,2,3,3,3-pentafluoro¬ propane, may be prepared by reacting 2,2,3,3,3- pentafluoro-1-propanol and p-toluenesulfonate chloride together to form 2,2,3,3,3-pentafluoropropyl- p-toluenesulfonate. Next, N-methylpyrrolidone,

30 lithium chloride, and the 2,2,3,3,3-pentafluoro- propyl-p-toluenesulfonate are reacted together to form l-chloro-2,2,3,3,3-pentafluoropropane. Finally, chlorine and the l-chloro-2,2,3,3,3,-pentafluoro¬ propane are reacted together to form 1,1-dichloro-

35 2,2,3,3,3-pentafluoropropane. A detailed synthesis is set forth in Example 1. Synthesis of 2 ,2-dichloro-l, 1, 1, 3 ,3- pentafluoro- propane (225a) . This compound may be prepared by reacting a dimethylformamide solution of 1, 1, l-trichloro-2 ,2, 2-trifluoromethane with chlorotrimethylsilane in the presence of zinc, forming l-(trimethylsiloxy)-2,2-dichloro- 3,3, 3-trifluoro-N,N-dimethylpropylamine. The l-(trimethyl-siloxy)-2 ,2-dichloro-3 , 3 ,3-trifluoro-N,N-d imethyl propylamine is reacted with sulfuric acid to form 2 ,2-dichloro-3 ,3 ,3-trifluoropropionaldehyde is then reacted with sulfur tetrafluoride to produce 2 , 2-dichloro-l, 1,1,3 ,3-pentafluoropropane.

Synthesis of 1,2-dichloro-l, 2 ,3 ,3.3- pentafluoro- propane (225ba) . This isomer may be prepared by the synthesis disclosed by 0. Paleta et al., Bull. Soc. Chim. Fr., (6) 920-4 (1986).

Synthesis of 1.2-dichloro-l.1.2.3.3- pentafluoropropane (22bb.. The systhesis of this isomer is disclosed by M. Hauptschein and L.A. Bigelow, J. Am. Chem. Soc, (73) 1428-30 (1951). The synthesis of this compound is also disclosed by A.H. Fainberg and W.T. Miller, Jr., J. Am. Chem. Soc, (79) 4170-4, (1957).

Synthesis of 1.3-dichloro-l.1.2.2.3- pentafluoropropane (225cb) . The synthesis of this compound involves four steps.

Part A - Synthesis of 2,2,3,3-tetrafluoro- propyl-p-toluenesulfonate. 406 grams of (3.08 mo) 2,2,3,3-tetrafluoropropanol, 613 gm (3.22 mol) tosyl chloride, and 1200 ml water were heated to 50°C with mechanical stirring. Sodium hydroxide (139.7 gm, 3.5 ml) in 560 ml water was added at a rate such that the temperature remained less than 65°C. After the addition was completed, the mixture was stirred at 50 C until the pH of the aqueous phase r was 6. The mixture was cooled and extracted with 1.5 liters methylene chloride. The organic layer was washed twice with 200 ml aqueous ammonia, 350 ml water, dried with magnesium sulfate, and distilled to give 697.2 gm (79%) viscous oil.

10

Part B - Synthesis of 1,1,2,2,3-pentafluoro¬ propane. A 500 ml flask was equipped with a mechanical stirrer and a Vigreaux distillation column, which in turn was connected to a dry-ice

,_£. trap, and maintained under a nitrogen atmosphere. The flask was charged with 400 ml N-methylpyr- rolidone, 145 gm (0.50 mol), 2,2,3,3-tetrafluoro¬ propyl p-toluenesulfonate (produced in Part A above) , and 87 gm (1.5 mol) spray-dried KF. The mixture was then heated to 190-200°C for about 3.25 hours

20 during which time 61 gm volatile product distilled into the cold trap (90% crude yield). Upon distillation, the fraction boiling at 25-28 C was collected.

25

Part C - Synthesis of 1,1,3-trichloro- 1,2,2,3,2-pentafluoropropane. A 22 liter flask was evacuated and charged with 20.7 gm (0.154 mol) 1,1,2,2,3-pentafluoropropane (produced in Part B above) and 0.6 mol chlorine. It was irradiated 100

30 minutes with a 450W Hanovia Hg lamp at a distance of about 3 inches (7.6 cm). The flask was then cooled in an ice bath, nitrogen being added as necessary to maintain 1 atm (101 kPa) . Liquid in the flask was removed via syringe. The flask was connected to a

35 dry-ice trap and evacuated slowly (15-30 minutes). The contents of the dry-ice trap and the initial liquid phase totaled 31.2 gm (85%), the GC purity being 99.7%. The product from several runs was combined and distilled to provide a material having ₅ b.p. 73.5-74°C.

Part D - Synthesis of 1,3-dichloro-l, 1,2,2,3- pentafluoropropane. 106.6 grams (0.45 mol) 1,1,3-trichloro-l,2,2,3,3-pentafluoropropane _Q (produced in Part C above) and 300 gm (5 mol) isopropanol were stirred under an inert atmosphere and irradiated 4.5 hours with a 450W Hanovia Hg lamp at a distance of 2-3 inches (5-7.6 cm). The acidic reaction mixture was then poured into 1.5 liters ice

-, _- water. The organic layer was separated, washed twice with 50 ml water, dried with calcium sulfate, and distilled to give 50.5 gm C1CF₂CF_CHC1F, bp 54.5-56°C (55%). ¹H NMR (CDC1₃): ddd centered at 6.43 ppm. J H-C-F - 47 Hz, J H-C-C-Fa - 12 Hz, J H-C-C-Fb - 2 Hz.

20

Synthesis of 1.1-dichloro-l.2.2. .3- pentafluoropropant (225cc) . This compound may be prepared by reacting 2,2,3,3-tetrafluoro-1-propanol

25 and p-toluenesulfonate chloride to form 2,2,3,3-tetra- fluoropropyl-p-toluesulfonate. Next, the 2,2,3,3- tetrafluoropropyl-p-toluenesulfonate is reacted with potassium fluoride in N-methylpyrrolidone to form 1,1,2,2,3-pentafluoropropane. Then, the 1,1,2,2,3- pentafluoropropane is reacted with chlorine to form

30 1,1-dichloro-l,2,2,3,3-pentafluoropropane.

Synthesis of 1.2-dichloro-l.1.3.3.3- pentafluoropropane (225d) . This isomer is commercially available from P.C.R. Incorporated of

35 Gainsville, Florida. Alternately, this compound may be prepared by adding equimolar amounts of 1,1,1,3,3-pentafluoropropane and chlorine gas to a borosilicate flask that has been purged of air. The c flask is then irradiated with a mercury lamp. Upon completion of the irradiation, the contents of the flask are cooled. The resulting product will be 1,2-dichloro-l, 1,3,3,3-pentafluoropropane.

10 Synthesis of 1,3-dichloro-l, 1,2,3.3- pentafluoropropane (225ea) . This compound may be prepared by reacting trifluoroethylene with dichlorotrifluoromethane to produce l,3-dichloro-l,2,3,3,3-pentafluoropropane. The ,(- 1,3-dichloro-l,1,2,3,3-pentafluoropropane is seperated from its isomers using fractional distillation and/or preparative gas chromatography.

Synthesis of 1.1-dichloro-l.2.3. .3-

20 pentafluoropropane (225eb) . This compound may be prepared by reacting trifluoroethylene with dichlorodifluoromethane to produce 1,3-dichloro- 1,1,2,3,3-pentafluoropropane and 1,1-dichloro- 1,2,3,3,3-pentafluoropropane. The 1,1-dichloro- 1,2,3,3,3-pentafluoropropane is separated from its

25 isomer using fractional distillation and/or . preparative gas chromatography. Alternatively, 225eb may be prepared by a synthesis disclosed by 0. Paleta et al., Bui. Soc. Chi . Fr., (6) 920-4 (1986). The 1,1-dichloro-l,2,3,3,3-pentafluoropropane can be

30 separated from its two isomers using fractional distillation and/or preparative gas chromatography.

It should be understood that the present compositions may include additional components which

35 form new azeotrope-like compositions. Any such compositions are considered to be within the scope of the present invention as long as the compositions are constant-boiling or essentially constant-boiling and contain all of the essential components described _c herein.

Inhibitors may be added to the present azeotrope-like compositions to inhibit decomposition; react with undesirable decomposition products of the 0 compositions; and/or prevent corrosion of metal surfaces. Any or all of the following classes of inhibitors may be employed in the invention: epoxy compounds such as propylene oxide; nitroalkanes such as nitromethane; ethers such as 1-4-dioxane; , _c unsaturated compounds such as 1,4-butyne diol; acetals or ketals such as dipropoxy methane; ketones such as methyl ethyl ketone; alcohols such as tertiary amyl alcohol; esters such as triphenyl phosphite; and amines such as triethyl amine. Other suitable inhibitors will readily occur to those

20 skilled in the art.

Having described the invention in detail and by reference to preferred embodiments thereof, it will be apparent that modifications and variations

25 are possible without departing from the scope of the invention defined in the appended claims.

The present invention is more fully illustrated by the following non-limiting Examples.

30

Example 1

This example is directed to the preparation of 1,l-dichloro-2,2,3,3,3-pentafluoropropane.

35 Part A - Synthesis of 2,2,3,3,3-pentafluoro¬ propyl-p-toluenesulfonate. To p-toluenesulfonate chloride (400.66 gm/2.10 mol) in water at 25°C was added 2,2,3,3,3-pentafluoro-1-propanol (300.8 gm) . The mixture was heated in a 5 liter, 3-neck separatory funnel type reaction flask, under mechanical stirring, to a temperature of 50°C. Sodium hydroxide (92.56 gm/2.31 mol) in 383 ml water(6M solution) was added dropwise to the reaction mixture via addition funnel over a period of 2.5 hours, keeping the temperature below 55°C. Upon completion of this addition, when the pH of the aqueous phase was approximately 6, the organic phase was drained from the flask while still warm, and. allowed to cool to 25°C. The crude product was recrystallized from petroleum ether to afford white needles of 2,2,3,3,3-pentafluoropropyl-p- toluenesulfonate (500.7 gm/1.65 mol, 82.3%).

Part B - Synthesis of l-chloro-2,2,3,3,3- pentafluoropropane. A 1 liter flask fitted with a thermometer, Vigreaux column, and distillation receiving head was charged with 248.5 gm (0.82 mol) 2,2,3,3,3-pentafluoropropyl-p-toluenesulfonate(produced in Part A above), 375 ml N-methylpyrrolidone, and 46.7 gm (1.1 mol) lithium chloride. The mixture was then heated with stirring to 140°C at which point, product began to distill over. Stirring and heating were continued until a pot temperature of 198°C had been reached at which point, there was no further distillate being collected. The crude product was re-distilled to give 107.2 gm (78%) of product.

Part C - Synthesis of 1,l-dichloro-2,2,3,3,3- pentafluoropropane. Chlorine (289ml/min) and l-chloro-2,2,3,3,3-pentafluoropropane(produced in Part B above) (1.72 gm/min) were fed simultaneously into a 1 inch (2.54cm) x 2 inches (5.08cm) monel reactor at 300 C. The process was repeated until c 184 gm crude product had collected in the cold traps exiting the reactor. After the crude product was washed with 6 M sodium hydroxide and dried with sodium sulfate, it was distilled to give 69.2 gm starting material and 46.8 gm 1,1-dichloro- 0 2,2,3,3,3-pentafluoropropane (bp 48-50.5°C). H NMR: 5.9 (t, J=7.5 H) ppm; ¹⁹F NMR: 79.4 (3F) and 119.8 (2F) ppm upfield from CFCl- .

Examples 2-6 5

The compositional range over which 225ca, methanol and cis-l,2-dichloroethylene exhibit constant-boiling behavior was determined. This was accomplished by charging selected 225ca-based binary compositions into an ebulliometer, bringing them to a 0 boil, adding measured amounts of a third component and finally recording the temperature of the ensuing boiling mixture. In each case, a minimum in the boiling point versus composition curve occurred; indicating that a constant boiling composition formed. 5

The ebulliometer consisted of a heated sump in which the 225ca-based binary mixture was brought to a boil. The upper part of the ebulliometer connected to the sump was cooled thereby acting as a condenser for

30 the boiling vapors, allowing the system to operate at total reflux. After bringing the 225ca-based binary mixture to a boil at atmospheric pressure, measured amounts of a third component were titrated into the ebulliometer. The change in boiling point was

35 measured with a platinum resistance thermometer. To normalize observed boiling points during different days to 760 millimeters of mercury pressure, the approximate normal boiling points of 225ca-based mixtures were estimated by applying a barometric correction factor of about 26 rnmHg/°C, to the observed values. However, it is to be noted that this corrected boiling point is generally accurate up to ± 0.4°C and serves only as a rough comparison of

10 boiling points determined on different days.

The following table lists, for Examples 2-6, the compositional range over which the 225ca/methanol/ cis-1,2-dichloroethylene mixture is constant boiling; •_jc i.e. the boiling point deviations are within ± about 0.5 C of each other. Based on the data in Table I, 225ca/methanol/cis-1,2-dichloroethylene compositions ranging from about 55-92.5/3-18/4.5-27 weight percent respectively would exhibit constant boiling behavior.

20

TABLE I

Starting Binary Example Composition (wt %)

2 225ca/methanol (94.2/5.8)

25 3 225ca/methanol (91.0/9.0)

4 225ca/cis-l,2-dichloroethylene (86.8/13.2)

5 225ca/cis-l,2-dichloroethylene (83/17)

6 225ca/cis-l,2-dichloroethylene (91/9)

Range over which Minimum

30 third component is Temperature

Ex__^ constant boiling (wt %) L°Q}

2 4.5-27.0 cis-1,2-dichloroethylene 45.2

3 4.8-21.4 cis-1,2-dichloroethylene 45.3

4 3.5-18.3 methanol ^" 45.4

5 3.0-34.0 methanol 45.2

6 4.0-15.0 methanol 45.4

35 E∑amples 7-16

The azeotropic properties of the below listed 5 dichloropentafluoropropane components (Table II) with methanol and cis-1,2-dichloroethylene are studied by repeating the experiment outlined in Examples 2-6 above except that one of the below listed dichloropentafluoro- 0 propane components is substituted for HCFC-225ca. In each case a minimum in the boiling point versus composition jrve occured indicating that a constant boiling composition forms between each dichloropentafluoropropane component, methanol and

-, _- cis-1, 2-dichloroethylene.

TABLE II

Dichloropentafluoropropane Component

20

2,2-dichloro-l, 1,1,3,3-pentafluoropropane(225a)

1,2-dichloro-l,2,3,3,3-pentafluoropropane(225ba)

1,2-dichloro-l,1,2,3,3-pentafluoropropane(225bb)

₂₅ 1,3-dichloro-l, 1,2,2,3-pentafluoropropane(225cb) 1, 1-dichloro-l,2,2,3,3-pentafluoropropane(225cc) 1,2-dichloro-l, 1,3,3,3-pentafluoropropane(225d) 1,3-dichloro-l, 1,2,3 ,3-pentafluoropropane(225ea)

30 1, 1-dichloro-l,2,3,3 ,3-pentafluoropropane(225eb)

1, l-dichloro-2,2,3,3,3-pentafluoropropane/ (mixture of 1,3-dichloro-l, 1,2,2,3-pentafluoro¬ propane 225ca/cb)

1, 1-dichloro-l,2 ,2,3 ,3-pentafluoropropane/(mixture of 1,3-dichloro-l, 1,2,2, 3-pentafluoropropane ³⁵ 225eb/cb) Examples 17-27

The azeotropic properties of the dichloropentafluoropropane components listed in Table III with methanol and a mixture of from about 75 to about 99.9 weight percent cis-1,2-dichloroethylene and from about 0.1 to about 25 weight percent trans-1,2-dichloroethylene are studied. This is accomplished by charging selected dichloropenta- fluoropropane-based binary compositions into an ebulliometer, bringing them to a boil, adding measured amounts of a third component and finally recording the temperature of the ensuing boiling mixture. In each case, a minimum in the boiling point versus composition curve occurs indicating that a constant boiling composition forms between each dichloropentafluoropropane component, methanol and 75-99.9/0.1-25 weight percent mixture of cis-1,2-dichloroethylene/trans-l,2-dichloroethylene.

TABLE III

Dichloropentafluoropropane Component

2,2-dichloro-l,1,1,3,3-pentafluoropropane(225a)

1,2-dichloro-l,2,3,3,3-pentafluoropropane(225ba)

1,2-dichloro-l,1,2,3,3-pentafluoropropane(225bb)

1,l-dichloro-2,2,3,3,3-pentafluoropropane (225ca)

1,3-dichloro-l,1,2,2,3-pentafluoropropane(225cb)

1,1-dichloro-1,2,2,3,3-pentafluoropropane(225cc)

1,2-dichloro-l,1,3,3,3-pentafluoropropane(225d) 1,3-dichloro-l,1,2,3,3-pentafluoropropane(225ea)

1,1-dichloro-l,2,3,3,3-pentafluoropropane(225eb) TABLE III (cont . ) Dichloropentafluoropropane Component

1,l-dichloro-2,2,3,3,3-pentafluoropropane/(mixture of 1,3-dichloro-l, 1,2,2,3-pentafluoropropane 225ca/cb)

1,1-dichloro-l,2,2,3,3-pentafluoropropane/(mixture of 1,3-dichloro-l,1,2,2,3-pentafluoropropane 225eb/cb)

0 Examples 28-38

The azeotropic properties of the dichloropentafluoropropane components listed in Table III with methanol and a mixture of from about 95 to 5 about 99.9 weight percent cis-1,2-dichloroethylene and from about 0.1 to about 5 weight percent trans-1,2-dichloroethylene are studied by repeating the experiments outlined in Examples 17-27 above except that a 95-99.9/0.1-5 weight percent mixture of 0 cis-1,2-dichloroethylene/trans-l,2-dichloroethylene is substituted for the 75-99.9/0.1-25 weight percent mixture of cis-1,2-dichloroethylene/trans-l,2- dichloroethylene. In each case, a minimum in the boiling point versus composition curve occurs 5 indicating that a constant boiling composition forms between each dichloropentafluoropropane component, methanol and 95-99.9/0.1-5 weight percent mixture of cis-1,2-dichloroethylene/trans-l,2-dichloroethylene.

0 Examples 39-49

The azeotropic properties of the dichloropentafluoropropane components listed in Table III with methanol and a mixture of from about 90 to -. - about 99.9 weight percent cis-1,2-dichloroethylene and from about 0.1 to about 10 weight percent trans-1,2-dichloroethylene are studied by repeating the experiments outlined in Examples 17-27 above except that a 90-99.9/0.1-10 weight percent mixture of the cis-1,2-dichloroethylene/trans-l,2- dichloroethylene is substituted for the 75-99.9/0.1-25 weight percent mixture of cis-1,2-dichloroethylene/ rans-l,2-dichloroethylene. In each case, a minimum in the boiling point versus composition curve occurs indicating that a constant boiling composition forms between each dichloropenta- fluoropropane component, methanol and 90-99.9/0.1-10 weight percent mixture of cis-1,2-dichloroethylene/ trans-1,2-dichloroethylene.

Claims

What -j,**; cla med is:

1. Azeotrope-like compositions consisting essentially of from about 55 to about 9275 weight percent dichloropentafluoropropane, from about 3 to about 18 weight percent methanol and from about 4.5 to about 27 weight percent 1,2-dichloroethylene which boil at about 47.5°C ± about 3.0°C at 760 mm Hg.

2. The azeotrope-like compositions of claim 1 wherein said compositions consist essentially of from about 67 to about 91 weight percent dichloropenta- fluoropropane, from about 3 to about 13 weight percent methanol and from about 6 to about 20 weight percent 1,2-dichloroethylene.

3. The azeotrope-like compositions of claim 1 wherein said compositions consist essentially of from about 70 to about 88 weight percent dichloropenta- fluoropropane, from about 3 to about 13 weight percent methanol and from about 9 to about 17 weight percent 1,2-dichloroethylene.

4. The azeotrope-like compositions of claim 1 wherein said compositions consist essentially of from about 75 to about 87 weight percent dichloropenta- fluoropropane, from about 4 to about 8 weight percent methanol and from about 9 to about 17 weight percent 1,2-dichloroethylene.

5. The azeotrope-like compositions of claim 2 wherein said dichloropentafluoropropane is

1,l-dichloro-2,2,3,3,3-ρentafluoropropane and said compositions boil at about 45.2 C at 760 mm Hg.

6. The azeotrope-like compositions of claim 5 wherein said compositions boil at about 45.2 C + about 1.0°C at 760 mm Hg. 7. The azeotrope-like compositions of claim 5 wherein said compositions boil at about 45.2°C ± about 0.

7°C at 760 mm Hg.

8. The azeotrope-like compositions of claim 5 wherein said compositions consist essentially of from about 70 to about 88 weight percent 1,1-dichloro- 2,2,3,3,3-pentafluoropropane, from about 3 to about 13 weight percent methanol and from about 9 to about 17 weight percent 1,2-dichloroethylene.

9. The azeotrope-like compositions of claim 5 wherein said compositions consist essentially of from about 74 to about 87 weight percent 1,1-dichloro-

2,2,3,3,3-pentafluoropropane, from about 4 to about 9 weight percent methanol and from about 9 to about 17 weight percent 1,2-dichloroethylene.

10. The azeotrope-like compositions of claim 5 wherein said compositions consist essentially of from about 76 to about 87 weight percent 1,1-dichloro- 2,2,3,3,3-pentafluoropropane, from about 4 to about 8 weight percent methanol and from about 9 to about 16 weight percent 1,2-dichloroethylene.

11. The azeotrope-like compositions of claim 2 wherein said 1,2-dichloroethylene is cis-1,2- dichloroethylene.

12. The azeotrope-like compositions of claim 2 wherein said 1,2-dichloroethylene is a mixture of from about 75 to about 99.9 weight percent cis-1,2- dichloroethylene and from about 0.1 to about 25 weight percent trans-1,2-dichloroethylene.

13. The azeotrope-like compositions of claim 2 wherein said 1,2-dichloroethylene is a mixture of from about 95 to about 99.9 weight percent cis-1,2- dichloro-ethylene and from about 0.1 to about 5 weight percent trans-1,2-dichloroethylene.

14. The azeotrope-like compositions of claim

2 wherein said 1,2-dichloroethylene is a mixture of from about 90 to about 99.9 weight percent cis-1,2-dichloroethylene and from about 0.1 to about

10 weight percent trans-1,2-dichloroethylene.

15. The azeotrope-like compositions of claim 4 wherein said 1,2-dichloroethylene is cis-1,2- dichloroethylene.

16. The azeotrope-like compositions of claim 4 wherein said 1,2-dichloroethylene is a mixture of from about 75 to about 99.9 weight percent cis-1,2-dichloroethylene and from about 0.1 to about 25 weight percent trans-1,2-dichloroethylene.

17. The azeotrope-like compositions of claim

4 wherein said 1,2-dichloroethylene is a mixture of from about 95 to about 99.9 weight percent cis-1,2- dichloroethylene and from about 0.1 to about 5 weight percent trans-1,2-dichloroethylene.

18. The azeotrope-like compositions of claim

5 wherein said 1,2-dichloroethylene is a mixture of from about 90 to about 99.9 weight percent cis-1,2-dichloroethylene and from about 0.1 to about 10 weight percent trans-1,2-dichloroethylene.

19. The azeotrope-like compositions of claim 5 wherein said 1,2-dichloroethylene is cis-1,2- dichloroethylene.

20. The azeotrope-like compositions of claim 5 wherein said 1,2-dichloroethylene is a mixture of from about 75 to about 99.9 weight percent - cis-1,2-dichloro-ethylene and from about 0.1 to about

25 weight percent trans-1,2-dichloroethylene.

21. The azeotrope-like compositions of claim 5 wherein said 1,2-dichloroethylene is a mixture of 0 from about 95 to about 99.9 weight percent cis-1,2-dichloroethylene and from about 0.1 to about 5 weight percent trans-1,2-dichloroethylene.

22. The azeotrope-like compositions of claim 5 5 wherein said 1,2-dichloroethylene is a mixture of from about 90 to about 99.9 weight percent cis-1,2-dichloroethylene and from about 0.1 to about 10 weight percent trans-l,2-dichloroethylene.

23. The azeotrope-like compositions of claim 0 8 wherein said 1,2-dichloroethylene is cis-1,2- dichloroethylene.

24. The azeotrope-like compositions of claim 8 wherein said 1,2-dichloroethylene is a mixture of 5 from about 75 to about 99.9 weight percent cis-1,2- dichloroβthylene and from about 0.1 to about 25 weight percent trans-1,2-dichloroethylene.

25. The azeotrope-like compositions of claim 0 8 wherein said 1,2-dichloroethylene is a mixture of from about 95 to about 99.9 weight percent cis-1, 2- dichloroethylene and from about 0.1 to about 5 weight percent trans-1,2-dichloroethylene.

5

26. The azeotrope-like compositions of claim 8 wherein said 1,2-dichloroethylene is a mixture of fro about 90 to about 99.9 weight percent cis-1,2- dichloroethylene and from about 0.1 to about 10 weight percent trans-1,2-dichloroethylene.

27. The azeotrope-like compositions of claim

9 wherein said 1,2-dichloroethylene is cis-1,2- dichloroethylene.

28. The azeotrope-like compositions of claim 9 wherein said 1,2-dichloroethylene is a mixture of from about 75 to about 99.9 weight percent cis-1,2- dichloroethylene and from about 0.1 to about 25 weight percent trans-1,2-dichloroethylene.

29. The azeotrope-like compositions of claim 9 wherein said 1,2-dichloroethylene is a mixture of from about 95 to about 99.9 weight percent cis-1,2- dichloroethylene and from about 0.1 to about 5 weight percent trans-1,2-dichloroethylene.

30. The azeotrope-like compositions of claim 9 wherein said 1,2-dichloroethylene is a mixture of from about 90 to about 99.9 weight percent cis-1,2- di „loroethylene and from about 0.1 to about 10 weight percent trans-1,2-dichloroethylene.

31. The azeotrope-like compositions of claim 2 wherein said dichloropentafluoropropane is a mixture of 1,l-dichloro-2,2,3,3-pentafluoropropane and 1,3-dichloro-l,1,2,2,3-pentafluoropropane.

32. The azeotrope-like compositions of claim 4 wherein said dichloropentafluoropropane is a mixture of 1,l-dichloro-2,2,3,3-pentafluoropropane and 1,3-dichloro-l,1,2,2,3-pentafluoropropane.

33. The azeotrope-like compositions of claim

11 wherein said dichloropentafluoropropane is a mixture of 1, l-dichloro-2,2,3,3-pentafluoropropane and 1,3-dichloro-l, 1,2,2,3-pentafluoropropane.

34. The azeotrope-like compositions of claim

12 wherein said dichloropentafluoropropane is a mixture of 1, l-dichloro-2,2,3,3-pentafluoropropane and 1,3-dichloro-l, 1,2,2,3-pentafluoropropane.

35. The azeotrope-like compositions of claim

13 wherein said dichloropentafluoropropane is a mixture of 1, l-dichloro-2,2,3,3-pentafluoropropane and 1,3-dichloro-l, 1,2,2,3-pentafluoropropane.

36. The azeotrope-like compositions of claim

14 wherein said dichloropentafluoropropane is a mixture of 1,l-dichloro-2,2,3,3-pentafluoropropane and 1,3-dichloro-l, 1,2,2,3-pentafluoropropane.

37. The azeotrope-like compositions of claim

15 wherein said dichloropentafluoropropane is a mixture of 1,l-dichloro-2,2,3,3-pentafluoropropane and 1,3-dichloro-l,1,2,2,3-pentafluoropropane.

38. The azeotrope-like compositions of claim

16 wherein said dichloropentafluoropropane is a mixture of 1,l-dichloro-2,2,3,3-pentafluoropropane and 1,3-dichloro-l,1,2,2,3-pentafluoropropane.

39. The azeotrope-like compositions of claim

17 wherein said dichloropentafluoropropane is a mixture of 1,l-dichloro-2,2,3,3-pentafluoropropane and 1,3-dichloro-l,1,2,2,3-pentafluoropropane.

40. The azeotrope-like compositions of claim

18 wherein said dichloropentafluoropropane is a mixture of 1, l-dichloro-2,2,3,3-pentafluoropropane and 1,3-dichloro-l, 1,2,2,3-pentafluoropropane.

- 41. The azeotrope-like compositions of claim

2 wherein an effective amount of an inhibitor is optionally present in said composition.

42. The azeotrope-like compositions of claim 0 41 wherein said inhibitor is selected from the group consisting of epoxy compounds, nitroalkanes, ethers, acetals, ketals, ketones, alcohols, esters, and amines.

43. A method of cleaning a solid surface 5 comprising treating said surface with an azeotrope-like composition of claim 2.

0

5

30

35