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Publication numberUS2371645 A
Publication typeGrant
Publication dateMar 20, 1945
Filing dateSep 16, 1943
Priority dateSep 16, 1943
Publication numberUS 2371645 A, US 2371645A, US-A-2371645, US2371645 A, US2371645A
InventorsAitchison Adam G, Petering Wilbur H
Original AssigneeWestvaco Chlorine Products Cor
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Degreasing process
US 2371645 A
Abstract  available in
Previous page
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Claims  available in
Description  (OCR text may contain errors)

Patented Mar. 20, 1945 DEGBEASING PROCESS Adam G. 'Aitehison, Westfleld, and Wilbur H.

Peterlng, Metuchen, N. 1., assignors to Westvaco Chlorine Products Corporation, New York, N. Y.. a corporation of Delaware No Drawing. Application September 16, 1943,

Serial No. 502,648

11 Glalms.

This invention relates to animprovement in degreasing processes and other processes wherein chlorinated solvents are used as solvent media.

It comprises particularly a method of. degreasing' articles with surfaces of a metal having a decomposing efiect on chlorinated grease solvents, such as aluminum goods, wherein grease is removed from such a metal surface by a chlorinated sol- I vent of a type normally subject to such decomposition, containing a minor amount of certain oxygen-containing organic compounds, advantageously ethers and oxides, which restrain such decomposition.

This application is a continuation-in-part of our copending application, Serial Number 386,544, filed April 2, 1941.

. Theremoval of grease iilms from metal surfaces by the application of grease solvents has been widely practiced during recent years. Numerous solvents have been employed, and numerous variations of the degreasing procedure have been suggested. In one method of operating, the metal article to be degreased is brought into contact with the solvent in the liquid phase. This may be accomplished by immersing the article in a large body of the solvent, or by spraying the solvent on the surface of the article. In another common method of degreasing, known generally as vapor-phase degreasing, a body of solvent is maintained at the boiling oint andin communication with a chamber adapted to contain a large body of the solvent vapor. The article to be degreased is brought into contact with this body of' vapor, and causes condensation of the solvent on the greasy metal surface. The condensed solvent removes grease and oil from the metal surface and drips oii, usually returning to the boiling body of the solvent. With it goes dirt, adhering to the greasy surface. This dirt often includes metal chips. In vapor-phase degreasers of this type, it is conventional to provide cooling coils or some equivalent arrangement near the top of the solvent vapor chamber to prevent or minimize the escape of -vapors and loss of solvent from the system; Solvent condensed by such cooling coils is generally substantially uncontaminated by either grease or dirt, and is usually returned to a clean solvent reservoir, which, in many cases,

is arranged to overflow into the solvent boiling compartment. In some cases, even when employing vaporphase degreasing, the article to be degreased is preliminarily dipped in a body of liquid solvent. When hot solvent is employed for this purpose, there is sometimesa subsequent dip in in degreasing operations. Among these, solvents of the chlorinated hydrocarbon type, including I .both saturated compounds such as carbon tetrachloride, ethylene dichloride. et cetera, and unsaturated compounds such as trichlorethylene, 'perchlorethylene, et cetera, have been widely employed because of their high grease-solvent capacity and their low inflammability. Several of these chlorinated compounds are considered noninflammable. Of the available solvents of this type, trichlorethylene is probably most widely used in degreasing. However, it is seldom used v without the addition of some stabilizer, adaptused for the purpose of inhibiting this decomposition. I

These previously known stabilizers are effective when present in minute amounts in preventing decomposition of trichlorethylene, for example during storage and during the usual degreasin operations applied to ferrous metals and several other metals. However, when the metal to be degreased is aluminum or an aluminum alloy, it

has been found that a. different type of decomposition of the solvent is encountered, and that this type of decomposition may occur even in the presence of stabilizers which are effective in all other cases. This form of decomposition of chlorinated solvents in contact with metallic aluminum or its alloys is evidenced by a rapid rise in acidity (largely hydrochloric acid), by pronounced discoloration of the solvent, and,jin the advanced stages of decomposition, by the formation of a tarry or gummy mass in the solvent.

Efforts have been made heretofore to eliminate or this type of decomposition by various special practices. In some instances, these practices have been partially successful, in that they have reduced formation of the above-men tioned tarry and gummy masses from the solvent, for example. However, when such results have been obtained, they have been accompanied by-undeslrable results of other types, such as increased acid development. It does not appear that prior to this invention there has been any satisfactory solution to the problem of decomposition encountered with the chlorinated solvents which are susceptible thereto, such as trichlorethylene, perchlorethylene, et cetera, when they ar kept in contact with aluminum ,or its alloys having a decomposing influence at high temperatures.

The present invention is based on our discovery that this metal-induced decomposition of chlorinated solvents, with production of hydrochloric acid and other deleterious decomposition products, is p v nt y t addition to the group, or a substituted ali hatic or aryl group. chlorinated hydrocarbon solvents of certain oxy- As noted below R and B may be substituted with gen-containing organic compoun Such as hydroxy, alkoxy. or with other substitutes such ganic oxides and ethers. For instance, that. all? as amino groups.

hatio ethers or oxides are particular y sui a e 5 For this purpose. Likewise, certain derivatives of complex and 03nd these ethers and oxides, such as amino-ethers, Ethyl Cellosolve hydroxy ethers, et cetera, may be employed with advantage in stabilizing chlorinated hydrocarbon HJFOH solvents against metal-induced decomposition. l a

The ethers and oxides also have other advan- Butyl 99110501 tages for the present purposes. First, as a class, r othey are readily soluble in chlorinated hydrocarmake}! bons and are completely compatible with such awe-idol solvents under service conditions. Under ordi- 5 nary conditions they do not react with the chlorinated hydrocarbons to form sludge or other deleterious by-products. Likewise, the ethers and G 1 d oxides do not attack metals since they are neither lycer he methyl ether alkaline nor acidic. In fact, the aliphatic ethers o CH'OCHI and oxides are themselves substantially inert and HOB stable under most conditions. In other words, HOCH,

the aliphatic ethers and oxides effectively stabmze chlorinated hydrocarbons against metal Glycerineamonomethyl ether induced decomposition without any deleterious x mon action, both during storage and under. service conditions. mocm We have used both straight chain and branched-chain ethers and oxides and obtained y r yl a cohol effective stabilization against metal-induced de- 30 '0 composition of the chlorinated solvents; The following ethers are illustrative of the types or ethers 1 that are eflective in the practice of our invention: PC3103 simple ethers Glycerine formal 36 0 Diethyl ether DialLvl ether onion Di-n-propyl ether Di-n-butyl ether l Di-isopropyl ether Diphenyl ether Hon on, or CH Ethers may be-used which have the general CH 0 type formula ROR where R and R mag be an aliphatic radical, either saturated or unsa ated, or an aryl group, or a substituted aliphatic or Glycenne Mural aryl radical. R and B may be the same or may 3K 0 be different radicals. 0 no on 5-0 1] II 1 no on Inner ethers or oaiides or CH ii a Propylene oxide o Ha I Hr-O moxane In the broad practice of our invention, we may 0 employ a wide variety of ethers and oxides as Q noted above. The simple symmetrical and the C CH? unsymmetrical ethers, the inner ethers or oxides,v m m substituted ethers and oxides particularly those containing hydroxy and-alkoxy, amino groups, Isobutylene oxide and the complex ethers having a number or sub- 0 on; stltuents but all containing the ether linkage are 1126/ all efiective. These oxygen-containing compgund: are gesalnerglltylemplioyedfili minor avanageouy eorero perceno e mphenylene oxide 0 amount of chlorinated solvent by weight. However, as the efiectiveness or these stabilizers varies to someextent with the type of compopnd employed, the particular percentage incorporated in the chlorinated hydrocarbon solvent may be 66 These ethers have the generic type formula varied to obtain the stabilization desired. Ordinarily it-is advantageous to add definite molar 0 Q percentages ofthe ether or oxides to the chlorior nated hydrocarbon solvents. However, for puro 10 poses oi the present invention, the more ether or oxide compound present, the more efiective the \o/ composition in restraining this metal-induced decomposition, This seems tobe true .because where R. and R may be a divalent aliphatic radi these oxygen compounds unite chemically with cal, either saturated or unsaturated, or an aryl (I the aluminum compounds that appear to cause asvaocs the metal-induced decomposition and thus the more oxygen compound present the more stabilization obtained; For "metal induced" decomposition claimed in this application it is generally advantageous to use about 1 mol of oxygen compound per 99 mols of chlorhydrocarbon. However, this amount may be increased with propdrtionately greater stabilization againstinetalinduced decomposition.

In the practice of our invention, many and various embodimentsthereof may be employed.

For instance, the chlorinated hydrocarbon. solvent, in addition to the stabilizers described, may also contain oneof the known stabilizers against normal decomposition, as previously mentioned,

such as aralkyl ethers of hydroquinone, described I in Pitman Patent 2,319,261.

'In one useful embodiment of the invention, propyl ether is employed as the oxygen-containing'organic compound. This ether is especially suited for the purpose, because in small amounts it tends to vaporize with the trichlorethylene, and therefore tends to remain with the solvent,

both as liquid and as vapor, during degreasing operations and purification of the solvent in solvent-extraction, dry-cleaning, and similar operations. For example, on distilling the solvent out of the boiling compartment, little, if any of this volatile ether is lost. The etherevaporates and rec'ondenses with the solvent. The propyl ether is highly effective in preventing the metal-induced type of decomposition of trichlorethylene and similar chlorinated solvents, and its moderate cost is another favorable factor. In general,

when working with any specific chlorinated solvent,- it is desirable to employ an ether or oxide forming a mixture which may be distilled with out loss of stabilizer.

One specific advantage resulting from the addition of suitable ethers and oxides to chlorinated embodiment of the present invention, a degreesing solvent was prepared containing 99.0 parts by weight of stabilized trichlorethylene, and 1 part by weight of propyl other. This solvent was used in a vapor-phase degreasing operation of the type previously described for degreasing aluminum surdegreasing solvent, as described hereinabove, is

that thepresence of a minor amount of the ether .or'oxide, with the resulting decrease in metalinduced decomposition, permits operation of the degreasing equipment for a longer period without the necessity of shutting down to clean out accumulations in the boiling compartment. As previously noted, the reactions involved in this metal-induced decomposition are somewhat ob-' scure. One explanation of these reactions is that th accumulation of non-volatile oils removed from the work during the degreasing operation, may raise the boiling point (or range) of the liquid in the boiling compartment of the degreaser to such an extent that reaction sets in between the chlorinated solvent and the finely divided aluminum or. other metal which has also been washed off the. work. This waste metal accumulating in the liquid solvent has large effective surface areas which are highly reactive, especially at the increased boiling temperature of thedirty solvent. It may be that the large metal surface catalyzes the decomposition, or it is possible that aluminum chloride forms at the surface of the metal and that this compound is the active decomposing agent.

Whatever the mechanism of the metal-induced decomposition, it has been necessary in the past to remove the accumulation of oily material and finely divided metal and metal compounds from the, boiling compartment at frequent intervals. This involves additional labor, loss of production during the cleaning period, and loss of solvent. These difiiculties are largely eliminated by operface's. No objectionable decomposition was en-' countered, ,even after continuing the operations without cleaning out the boiling compartment of the degreaser for considerably longer than had beenpossible before the use of the ether in accordance with this invention.

In the operation justdescribed, it was found that the ether vaporized with the trichlorethylene, was condensed, and returned to the liquid compartments with the trichlorethylene.

These chlorinated solvents, such as trichlorethylene, containing minor amounts of ethers or oxides,*are particularly adapted'for use in degreasing aluminum and its alloys. Such solvents are also useful in degreasing other metals, including zinc and magnesium and'their alloys as well as iron, steel, copper, et cetera.,

While we have particularly described our invention hereinabove with respect to certain ethers and oxides, it will be obvious to the skilled in the art that the invention is not limited to the specific examples shown, but may be practiced and embodied within the scope of the claims hereinafter made.

What weclaim is:

1. As an improvement in degreasing surfaces .of aluminum and its alloys with chlorinated hydrocarbon solvents normally subject to deterioration in the presence of aluminum, the improvement which comprises maintaining, inadmixture s with such chlorinated solvents, a minor amount of an organic ether to inhibit such metal-induced decomposition thereof.

2'. As an improvement in degreasing surfaces of aluminum and its alloys with chlorinated hydrocarbon solvents normally subject to deterioration in the presence of aluminum,.the improve-t ment which comprises maintaining, in admixture with such chlorinated solvents, a minor amount of an organic inner ether to inhibit such metal-"1 induced decomposition thereof.

3. As an improvement in degreasing surfaces is propyl ether.

oi metals of the class consisting of aluminum and its alloys having a decomposing effect on chlorinated hydrocarbon grease solvents, which comprises establishing a body of grease solvent in communication with a space adapted to receive vapors therefrom, said solvent comprising a maior proportion of chlorinated hydrocarbon solvent, i normally subjectto decomposition in the presence of such metal surfaces, and a minor proportion of an organic ether having the property of restraining decomposition of such solvents in the presence of saidmetal surfaces, boiling said body of grease solvent and thereby maintaining a body of vapors thereof in said vapor space,. contacting the metal surface to be decreased with said body of vapors and returning the solvent condensed ADAM G. AITCHISON. wmaon H. PE'IERING.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2423343 *Apr 27, 1945Jul 1, 1947Westvaco Chlorine Products CorProcess of degreasing aluminum and magnesium surfaces
US2517893 *May 13, 1946Aug 8, 1950Du PontStabilized chlorohydrocarbon cleaning composition
US2517894 *May 13, 1946Aug 8, 1950Du PontMetal degreasing composition
US2517895 *May 13, 1946Aug 8, 1950Du PontStabilized chlorohydrocarbon cleaning composition
US2643961 *May 22, 1948Jun 30, 1953Anaconda Wire & Cable CoCleaning cupreous articles
US2740734 *Oct 11, 1949Apr 3, 1956Detrex CorpMethods for cleaning food containers and the like
US2742509 *Jul 23, 1954Apr 17, 1956Du PontStabilization of chlorinated hydrocarbons
US2795623 *Nov 15, 1954Jun 11, 1957Du PontStabilization of chlorinated hydrocarbons
US2802885 *Aug 16, 1954Aug 13, 1957Air ReductionStabilization of chlorinated hydrocarbons with 3, 3-dimethoxy-2-methyl-butan-2-ol
US2811252 *Mar 30, 1954Oct 29, 1957Dow Chemical CoMethyl chloroform inhibited with dioxane
US2818446 *Oct 25, 1956Dec 31, 1957Du PontStabilization of chlorinated hydrocarbons
US2838458 *Sep 30, 1955Jun 10, 1958Dow Chemical CoInhibited methyl chloroform
US2857922 *Oct 9, 1951Oct 28, 1958Shell DevApparatus for cleaning tube bundles
US2868851 *Jul 26, 1954Jan 13, 1959Diamond Alkali CoStabilization of chlorinated hydrocarbons with acetylenic ethers
US2870094 *Sep 28, 1955Jan 20, 1959Eastman Kodak CoPhotographic film cleaning solutions
US2904600 *Apr 4, 1956Sep 15, 1959Du PontStabilization of chlorinated hydrocarbons
US2923747 *Apr 7, 1958Feb 2, 1960Dow Chemical CoPrevention of corrosion
US2970113 *May 31, 1957Jan 31, 1961Dow Chemical CoStabilization of 1, 1, 1-trichloroethane
US2981759 *Feb 8, 1956Apr 25, 1961Air ReductionStabilization of chlorinated hydrocarbons with a synergistic combination of a tertiary acetylenic alcohol, dioxane, and a volatile basic organic nitrogen-containing organic compound
US2998461 *Apr 15, 1959Aug 29, 1961Hooker Chemical CorpStabilization of trichloroethylene
US3008999 *Oct 8, 1959Nov 14, 1961Argus ChemStabilization of methylchloroform
US3025331 *Oct 31, 1958Mar 13, 1962Pittsburgh Plate Glass CoStabilization of liquid halogenated aliphatic hydrocarbons
US3043888 *Feb 9, 1959Jul 10, 1962Pittsburgh Plate Glass CoStabilization
US3049571 *Mar 18, 1960Aug 14, 1962Dow Chemical CoStabilized degreasing solvent
US3070634 *Mar 1, 1960Dec 25, 1962Pittsburgh Plate Glass CoStabilization of methylchloroform
US3074890 *Oct 27, 1958Jan 22, 1963Ethyl CorpStable solvent composition
US3099694 *May 27, 1960Jul 30, 1963Ethyl CorpStable methylchloroform compositions
US3113154 *May 27, 1960Dec 3, 1963Ethyl CorpStable methylchloroform compositions
US3113155 *May 27, 1960Dec 3, 1963Ethyl CorpChlorinated solvents stabilized with mixtures of a dioxolane compound, a nitro-aliphatic compound, and an aliphatic carboxylic acid ester
US3113156 *May 27, 1960Dec 3, 1963Ethyl CorpChlorinated solvents stabilized with mixture of a dioxolane compound and a nitroaliphatic compound
US3120567 *Mar 21, 1961Feb 4, 1964Pittsburgh Plate Glass CoStabilization of perchloroethylene with a mixture of an epoxide and an alkoxynitrile
US3128315 *Mar 13, 1961Apr 7, 1964Pittsburgh Plate Glass CoMethylchloroform stabilized with dialkylethers of alkylene glycols
US3133885 *May 5, 1960May 19, 1964Detrex Chem IndMethod of inhibiting metal corrosion by amine-stabilized unsaturated chlorinated hydrocarbons
US3278397 *Jul 18, 1963Oct 11, 1966Monsanto CoRemoval of hci from vinyl chloride by distillation in the presence of styrene oxide and a pyridine
US3278615 *Apr 8, 1963Oct 11, 1966Dow Chemical CoStabilization of haloalkanes with fluoroethers of the type
US3285857 *Oct 26, 1962Nov 15, 1966Ici LtdStabilized methyl chloroform composition
US3303107 *Jul 18, 1963Feb 7, 1967Monsanto CoPurification of vinyl chloride containing hci as an impurity by distillation in the presence of an epoxy compound
US3360575 *May 19, 1966Dec 26, 1967Dow Chemical CoStabilized solvent system
US3397246 *Apr 26, 1966Aug 13, 1968SolvayStabilized chlorinated hydrocarbons
US3475503 *Dec 1, 1967Oct 28, 1969Dow Chemical CoStabilization of 1,1,1-trichloroethane
US3496241 *Mar 2, 1967Feb 17, 1970Fmc CorpStabilization of chlorinated hydrocarbons
US3499047 *Feb 3, 1958Mar 3, 1970Ppg Industries IncStabilized compositions
US3505415 *Aug 18, 1967Apr 7, 1970Dynamit Nobel AgProcess for stabilizing 1,1,1-trichlorethane
US3519694 *Oct 22, 1965Jul 7, 1970Dow Chemical CoStabilization of methyl chloroform
US3532761 *May 7, 1969Oct 6, 1970Ppg Industries IncStabilization of methyl chloroform
US3535392 *Feb 26, 1969Oct 20, 1970Ppg Industries IncStabilized methylchloroform
US3839087 *Nov 17, 1972Oct 1, 1974Diamond Shamrock CorpPerchloroethylene vapor degreasing process
US3876712 *Aug 10, 1972Apr 8, 1975Ethyl CorpStabilized halogenated hydrocarbons
US4687523 *Jul 30, 1986Aug 18, 1987Mobil Oil CorporationMethod for cleaning a core sample from a subterranean formation of solid contaminant particles
US5492645 *Jan 13, 1994Feb 20, 1996Dipsol Chemicals Co., Ltd.Deterging solvent composition with n-or iso-propyl bromide, a nitroalkane, and an ethylene glycol monoalkyl ether
US5665170 *Nov 1, 1995Sep 9, 1997Albemarle CorporationSolvent system
US5665172 *Sep 20, 1995Sep 9, 1997Dipsol Chemicals Co., Ltd.Method for washing an article with composition having a brominated hydrocarbon and stabilizer
US5665173 *Feb 29, 1996Sep 9, 1997Albemarle CorporationMovie film cleaning process
US5669985 *Feb 29, 1996Sep 23, 1997Albemarle CorporationMovie film cleaning process
US5679632 *Feb 29, 1996Oct 21, 1997Albemarle CorpMovie film cleaning solvent comprising n-propylbromide
US5690862 *Nov 1, 1995Nov 25, 1997Albemarle CorporationNo flash point solvent system containing normal propyl bromide
US5707954 *Mar 1, 1996Jan 13, 1998Albemarle CorporationStabilized brominated alkane solvent
US5792277 *Jul 23, 1997Aug 11, 1998Albemarle CorporationN-propyl bromide based cleaning solvent and ionic residue removal process
US5824162 *Mar 28, 1997Oct 20, 1998Lawrence Industries, Inc.Molecular level cleaning of contaminates from parts utilizing an environmentally safe solvent
US5938859 *Mar 28, 1997Aug 17, 1999Lawrence Industries, Inc.Molecular level cleaning of contaminants from parts utilizing an environmentally safe solvent
US6176942Aug 16, 1999Jan 23, 2001Lawrence Industries, IncSolvent mixture for use in a vapor degreaser and method of cleaning an article in a vapor degreaser utilizing said solvent
EP0609004A1 *Jan 18, 1994Aug 3, 1994Dipsol Chemical Co., LtdDeterging solvent composition and a method for washing an article with the same
U.S. Classification134/31, 510/271, 570/118, 510/273
International ClassificationC23G5/00, C23G5/028
Cooperative ClassificationC23G5/02877, C23G5/0288
European ClassificationC23G5/028P2E, C23G5/028P2D