US2978416A - Concentrated aqueous detergent composition - Google Patents

Description

United States Patent CONCENTRATED AQUEOUS DETERGENT COMPOSITION Marvin M. Fein, Westfield, N.J., and Cecil A. Friedman,

Buffalo, N.Y., assignors to Allied Chemical Corporation, a corporation of New York No Drawing. Filed July 14, 1955, Ser. No. 522,165

3 Claims. (Cl. 252-161) This invention relates to concentrated aqueous detergent compositions comprising anionic detergents of the higher alkylbenzene sulfonate type. It relates more particularly to aqueous liquid detergent compositions containing in excess of 15% by weight of water-soluble salts of a mixture of higher alkylbenzene sulfonates containing 9 to 18 non-aromatic carbon atoms together with minor amounts of certain additives which modify the solubility and other properties of the higher alkylbenzene sulfonates.

The higher alkylbenzene sulfonates are valuable detergents, wetting agents, penetrating agents, and emulsifying agents. They owe their valuable surface-active properties in part to the fact that they are partly hydrophobic and partly hydrophilic. This molecular complexity leads to the disadvantage, however, that their solubility in water at ordinary atmospheric temperatures is limited.

The anionic detergents of the higher alkylbenzene sulfonate type are generally produced in the form of water-soluble salts such as the alkali metal salts, and especially the sodium salt. They generally come into the market in the form of the dried solid. Since they are mostly used in aqueous solution, it is necessary for the user to dissolve them in water or other aqueous media before use.

To avoid the necessity of dissolving the higher alkylbenzene sulfonates at the point of use, it has been proposed to prepare stock solutions of the sulfonates in water and dilute them to the required degree at the point of use. One disadvantage of the solutions heretofore employed is the relatively low maximum concentration of sulfonate obtainable at ordinary atmospheric temperatures. A further disadvantage is the precipitation of the sulfonate and inorganic sulfate. from saturated solutions which occurs upon a decrease in the surrounding temperature; it is costly and troublesome to redissolve the precipitated matter. These disadvantages represent a handicap to the shipment of detergent solutions in tank cars and the storage of the solutions in storage tanks exposed to the atmosphere, especially in cold weather.

According to the present invention, concentrated aqueous detergent compositions are produced containing anionic detergents of the higher alkylbenzene sulfonate type and, as modifiers of the solubility and other properties thereof, (1) a water-soluble salt of a benzene sulfonic acid containing a maximum of 6 non-aromatic carbon atoms, and (2) an open-chain diol of the type specified hereinafter.

We have discovered that, by incorporating into aqueous solutions of such anionic detergents a minor amount of a water-soluble salt of benzene .sulfonic acid or a lower alkyl derivative thereof (containing 1 to 6 non aromatic carbon atoms) and a small amount of an open chain diol of the type hereinafter set forth, detergent compositions can be obtained in the form of concentrated aqueous solutions having in excess of 25% and as high as 45% by weight of a water-soluble salt of a higher alkylbenzene sulfonate (or a mixture of watersoluble salts of such sulfonates), which solutions have the ability to remain clear not only at normal atmospheric temperatures but in many cases even at lower temperatures, such as below 0 C.

We have discovered that the critical solution temperatures of concentrated aqueous solutions of watersoluble salts of said higher alkylbenzene sulfonic acids can be lowered substantially by including in said solutions both of said modifiers in a minor total amount, without reducing the detergent properties of the solutions to a substantial degree. This result is surprising because the addition of water-soluble salts of toluene sulfonic acid to such concentrated aqueous solutions reduces substantially the foaming power in hard water of said detergents.

(The term critical solution temperature-cloud point or haze point--as employed herein refers to the temperature at which the solution, upon cooling, begins to become turbid.)

Preferably, in accordance with the present invention,

the higher alkylbenzene'sulfonate and the. benzene sulfonate having a maximum of 6 non-aromattic carbon atoms are present in the form of a mixture obtained by co-sulfonating a higher alkylbenzene hydrocarbon in admixture with a minor amount of benzene or a lower alkylbenzene, since a somewhat greater increase in solubility (lowering of the critical solution temperature) is obtained than by mixing the separately prepared sulfonates.

The anionic detergents of the higher alkylbenzene sulfonate type employed in accordance with the present invention comprise essentially water-soluble salts. or

mixtures of water-soluble salts of mononuclear aryl hydrocarbon sulfonic acids that contain a total of 9 to 18 non-aromatic carbon atoms, and preferably they have as a nuclear substituent a higher alkyl radical which contains 12 to 16 carbon atoms. 7 t

Advantageous higher alkylbenzene sulfonate detergents for use in accordance withv the present invention are t mixturesof neutral water-soluble salts, especially sodium salts, of such higher alkylaryl sulfonic acids, particularly those in which the higher alkyl radicals contain, on the average, from about 12 to about 16 carbon atoms. Higher alkylaryl sulfonate detergents especially advantageous for use in accordance with the present invention are those consisting essentially of higher alkylbenzene (or higher 'alkyltoluene) 'sodium'sulfonate mixtures of which the higher alkyl groups correspond to the hydrocarbons of a petroleum fraction of a kerosene boiling range, herein referred to as keryl benzene su1-' fonates. t p w The said anionic detergents can be obtained in various ways. Thus they can be prepared by condensing a mono.- nuclear aromatic hydrocarbon (such as, benzene, toluene,

Patented Apr. 4, 1961 xylene, etc.) with an alkylating agent adapted to introduce a higher alkyl radical and containing enough non-aromatic carbon atoms per molecule to make the total of nonaromatic carbon atoms in the alkylate between 9 and 18 (such as, a higher alcohol, a higher alkyl halide, an olefin or olefin polymer, or a commercial mixture of such alkylating agentsfor example, chlorinated kerosene, a mixture of olefins, or a trimer, tetramer or pentamer of propylene or mixture thereof, etc.) to form an alkylated aromatic compound or mixture of such compounds, or by condensation of ethylenewith an alkylaromatic hydro. carbon (suchas, toluene or cumene); sulfonating the re sulting alkylated benzene compound or mixture, with or without intermediate purification operations (or, in some cases, sulfonating in the course of the condensation); and neutralizing the resulting sulfonic acid product to form the higher alkylbenzene-sulfonate, usually in the form of the alkali metaL especialIy sodium, salt.

It is advantageous to use, as the source of the alkyl radical introduced into the aromatic nucleus, naturallyoccurring or synthetically-prepared non-aromatic hydrocarbon rnixtures. For example, the various fractions of petroleum ditillates, hydrogenated coal distillates, polymerized gaseous olefins, etc., represent available and inexpensive sources of alkylating agents for thepreparation of the higher alkylarylsulfonates. A preferred alkylating agent is the mixture of chlorfhydrocarbons resulting from the chlorinationof a selected petroleum distillate, preferably of the kerosene boiling range. Such a mixture of chlor-hydrocarbons can be prepared, for example, by

chlorinating with gaseous chlorine a kerosent fraction of i the petroleum distillate.

Higher alkylbenzene sulfonate detergent compositions of this type and methods for their preparation are disclosed, for example, in US. Patents 2,233,408; 2,247,365; 2,267,725; 2,283,199; 2,298,650; 2,298,651; 2,298,696; 2,333,830; 2,340,654; 2,364,782; 2,387,572; 2,393,526; and 2,477,383; and British Patent 416,379.

The low molecular weight benzene sulfonates employed as solubilizing agents in accordance with the present invention comprise the water-soluble salts of benzene ,sulfonic acid and its homologs which contain a maximum of 6 non-aromatic carbon atoms, such as toluene, xylene, cumene, cymene, butyl benzene, amyl benzene, hexyl benzene, butyl xylene, etc. They include the alkali metal, ammonium, and organic amine salts. In view of their ready availability and low cost, the sodium salts are preferably employed.

The choice of the particular benzene sulfonate of low molecular weight employed as solubilizing agent for the higher alkylbenzene sulfonate will depend upon a number of factors; such as relative cost, odor and color of the final detergent solution, etc. Sodium xylene sulfonate and sodium cumene sulfonate exert a greater solubilizing effect upon the higher alkylbenzene sulfonates than do benzene sulfonate and toluene sulfonatebut, when employed for the manufacture of a detergent solution by the co-sulfonation procedure, their use'leads to detergent solutions having an undesirable odor and a higher degree of color. Accordingly, for the preferred manufacture of detergent solutions having general .utility and acceptability, as well as a desirably low critical solution temperature at high concentrations of higher alkylbenzene sulfonate, sodium toluene sulfonate is preferred.

The low molecular weight benzene sulfonates can be incorporated into the detergent solutions in any desired manner and at any stage of the preparation of the solutions. Thus, they may be preformed and added to the detergent solution, or one of the components thereof, during the preparation of the solution.

In the preferred practice'of our invention, the benzene sulfonate of low molecular weight is incorporated into the detergent solution during the course of manufacture of the higher alkylbenzene sulfonate, by co-sulfonating a 4 mixture of a hydrocarbon of the benzene series containing 9 to 18 non-aromatic carbon-atoms and a hydrocarbon of the benzene series containing not more than 6 non-aromatic carbon atoms, the latter being present in an amount from 3% to 25% of the weight of said mixture. The effect of the bezene sulfonate of low molecular weight as a depressor of the critical solution temperature of the detergent solution is greater when the solution is prepared by the cosulfonating procedure. On the other hand, in some cases the co-sulfonation procedure leads to a some what lowered foaming action of the resulting detergent solution in hard water. Thus, the specific procedure employed will depend to some extent upon the result desired to be obtained.

The open-chain diols employed in accordance with the present invention include'the variousmembers ofthe class corresponding to the formula HO-- RO) H wherein R0 represents a radical selected from the group consisting of the CH CI-I O radical, the

radical and the --CHCH:O-

radical, and

n represents an integer from 1 through 150, but not more than 10 R0- radicals contain 3 carbon atoms.

Thus, they include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol and higher polyethylene glycols having molecular weights from about 200 through 6000; propylene glycol, dipropylene glycol, tripropyleneglycol andhigher polypropylene glycols having molecular weights through about 600; and mixed ethylene-propylene glycol ethers having a maximum total of RO- radicals of which not more than 10 RO radicals are propoxy radicals. They may be employed in the form of the individual polyglycol (glycol ether), or in the form of mixtures such as are obtained commercially by the reaction of a glycol with ethylene and/or propylene oxide. Preferred polyglycols employed in accordance with the present invention are polyethylene glycol mixtures having an average molecular weight of about 200 to about 1250, inasmuch as said polyglycol mixtures produce a superior increase in the foaming action of the resulting detergent solution when employed in hard water.

The open-chain diol can be incorporated into the detergent solution at any stage of the manufacture thereof subsequent to the formation of the sulfonic acid, and in any order with respect to the other components of the solution. An advantageous procedure for the manufacture of the solution involves carrying out the neutralization of the higher-alkylbenzene sulfonic acid in an aqueous medium containing the open-chain diol.

The amounts of benzene sulfonate of low molecular weight and open-chain diol employed relative to the amount of higher alkylbenzene sulfonate can be varied depending upon the result desired to be obtained. Thus, for the preparation of aqueous liquid detergent solutions containing, by weight, 15% to 45% of higher alkylbenzene sulfonate, amounts of benzene sulfonate of low molecularweight ranging from 0.5% to 15%, preferably 2% to 15%, and amounts of diol ranging from 0.5% to 10%, preferably 1% to 5% of the weight of the final solution, may be employed, a greater lowering of the critical solution temperature being generally obtained with the larger amounts. of solubilizing sulfonate and open-chain diol. In general the solutions contain 40% to 75% of water. Compositions of particular utility as stock solutions in accordance with our invention are aqueous liquid solutions containing as their essential components, by weight, about 25% to about 45%, especially about 30% of sodium kerylbenzene sulfonate, about 3% to about 12%, especially about of sodium toluene sulfonate (preferably co-sulfonated), and about 1% to about 5%, especially about 2% of a mixture of polyethylene glycols having an average molecular weight of 200 to 1250 and a major proportion of which have molecular weights within this range.

The invention will be illustrated by the following specific examples, but it is to be understood that it is not limited to the details thereof and that changes may be made without departing from the scope of the invention.

The temperatures are in degrees centigrade and the parts and percentages are by weight, unless designated as parts by volume. Where parts are by volume, the amount signifies the volume occupied by the same number of parts by weight of water at 4 C.

Example 1 Part 1.-A refined higher alkylbenzene was prepared in a manner similar to that described in U.S.P. 2,364,782 by chlorinating a kerosene fraction of petroleum distillate; condensing the resulting chlorination product with benzene in the presence of anhydrous aluminum chloride; separating the alkylbenzene-containing oil from the condensation reaction mixture by decantation; recovering an alkylbenzene mixture by fractional distillation of the oil; and subjecting the alkylbenzene mixture to a refining extraction treatment with sulfuric acid. The kerosene fraction had a boiling point ranging from about 198 to 251 and consisted predominantly of C -C parafiin and naphthene hydrocarbons. The keryl benzene had an average molecular weight of 260 to 265.

Part 2.Detergent solutions were prepared from the resulting keryl benzene in the following manner:

150 parts of the keryl benzene, or 150 parts of a mixture of the keryl benzene and toluene in the proportions set out below in Table 1, were reacted with 210 parts of 100% sulfuric acid at 55-60 for one hour. The sulfonation mass was agitated with 50 parts of water, whereafter it was allowed to settle out and stratify. The lower layer of spent sulfonating acid was withdrawn. The upper layer of sulfonation product, weighing 220 parts,

consisted of aromatic sulfonic acid(s) and some free sulfuric acid. Separate streams of the sulfonation product and of 30% NaOH solution (about 90-100 parts by volume) were charged simultaneously to 150 parts of an aqueous medium consisting of water or water containing a commercial polyethylene glycol having an average molecular weight of about 400 in the amounts set out in Table 1. Near the end of the neutralization procedure, the batch was treated successively with (1) a solution of 3 parts of sodium tripolyphosphate in 10 parts by volume of waterwhich serves as a sequestering agent for iron and other undesirable metallic compounds in the subsequent use of the detergent solutions, (2) 1 part by volume of 10% sodium hypochlorite solution-which functions as a purifying agent in accordance with U.S.P. 2,333,830, and (3) a solution of 0.7 part of sodium bi sulfite in 2 parts by volume of waterwhich serves to decompose the residual sodium hypochlorite in the treated solution. The acidity of the solution was finally adjusted to a grass-green color test on Nitrazine Yellow test paper (a pH 6.3 to 6.7).

The resulting solutions were tested for critical solution temperature (CST) after being diluted to a total solutes concentration of 41%. (The total solutes frac tion is the residue after evaporation of the water; it includes all other components of the solution except the water.)

The results obtained are set out in Table 1.

TABLE 1 Polyethylene Ross-Miles Test Glycol for Hard Water CST in Foaming Weight Weight C. at M of Keryl oi Benzene Toluene Average Salutes Solutes Foam Molecular Weight Cone. Concen- Height, Weight tratlon, mm.

Percent the solution to be tested is immersed in a cooling bath containing ice and salt, to a depth such that the liquid level of the sample remains just above the liquid level of the cooling bath. The'sample is allowed to cool slowly while being stirred with a thermometer. The temperature at which turbidity first becomes evident is taken as the. critical solution temperature.

The detergent solutions were tested for hard water foaming by the Ross-Miles procedure described in Oil and Soap, volume 18, pages 99-102 (May 1941). The detergent solutions were diluted with water having a hardness of 15 to give a test solution having a concentration of solutes (originating from the detergent solution) as given in the table. The last column of the table gives the heights of the foam columns obtained from the different solutions by the test procedure.

ExampleZ Detergent solutions were prepared in the manner described in Example 1, Part 2, from a kerylbenzene obtained as described in Example 1, Part 1. The proportions of components were as set out below in Table 2. The polyethylene glycols were commercial products having the 1 average molecular weights set out in the table. The results obtained are set out in Table 2.

The data set forth in Tables 1 and 2 show that polyethyl ene glycols having average molecular weights of 200, 400 and 600 have a synergistic effect, in that they boost the foaming capacity of the detergent in hard water and thereby overcome or reduce the loss in hard water foaming capacity resulting from the use of toluene sulfonate as a solubilizer. Thus, the data show that, while toluene sulfonate lowers the critical solution temperature of kerylbenzene sodium sulfonate detergent solutions, it also lowers the hard water foaming capacity of these solutions. Addition of the polyglycols, while further lowering the critical solution temperatures of the solutions, increases their hard water foaming capacity, the increase in hard water foaming capacity resulting from the use of the polyglycols being greater than the decrease in hard water foaming capacity resulting from the inclusion of the toluene sulfonate. Toluene sulfonate and the polyglycols'thus 7 Example 3 Detergent solutions were prepared in the manner described in Example 1, Part 2, from a commercial higher alkylbenzene mixture resulting from the alkylation of benzene with a propylene polymer, predominantly the tetramer (Detergent Alkylate No. 2 of Atlantic Refining Co.) The proportions of components were as set out below in Table 3.

Detergent solutions were prepared in the manner described in Example 1, Part 2, from a kerylbenzene obtained as described in Example 1, Part 1. The proportions of components were as set out below in Table 4. The polyethylene glycol was a commercial product having an average molecular weight of about 400.

The results obtained are set out in Table 4.

TABLE 4 Lower Allrylbenzene Weight of Weight of Kcryl Polyethyl- CST at 41% Benzene, Parts ene Glycol Solu tes Kind Weight, (M.W. 400), Gone, C.

Parts Parts 135 Toluene... 15 11 135... ...do 15 10 0 145... 5 0 48 145 5 20 0 145.-. 5 0 38 145 5 20 1 150 0 78 150- 20 13 Example 5 Detergent solutions were prepared in the manner de scribed in Example 1, Part 2, from kerylbenzenes obtained as described in Example 1, Part 1, with and without the addition of toluene in the sulfonation. The results obtained with parts by weight of various diols are set out in Table 5. The products identified as Carbowax were commercial polyethylene glycols having the average molecular weight represented by the number following the name. The products identified as Pluronic L-44 and F-68 were ethylene oxide derivatives of polypropylene glycols corresponding to the formula in which a, b and c are integers.

In Pluronic L-44, the central core of propoxy groups has an average molecular weight of 1000-1200, the terminal chains of ethoxy groups have a total molecular weight of approximately 800-1000, the total molecular weight being 2000. In Pluronic" F-68, the central core of propoxy groups has a molecular weight of 18002100 and the 6 terminal chains of ethoxy groups have a molecular weight of 5900 to 6200, the total molecular weight being 8000.

The critical solution temperatures were determined on the solutions as obtained, without as in the preceding examples first diluting them to a total solutes concentration of 41%. Exclusive of the diol additive, the composition Tof the total solutes fraction of the detergent solutions averaged about as follows: Sodium kerylbenzene sulfonate 75.4%, sodium toluene sulfonate 12.8%, sodium tripolyphosphate 1.3%, other alcohol insolubles (principally sodium sulfate) 10%, and sodium chloride 0.5%, all by weight.

TABLE 5 Detergent Solution From Co-Sulionated Detergent Solution Mixture of 90% From Sullonated Keryl Benzene Keryl Benzene Diol Additive and 10% Toluene CST, solutes CST, Solutes 0. Cone.. 0. Cone Percent Percent None +12. 5 45. 5 90 47. 5 Ethylene GlycoL. +5.0 47.9 75 46.8 Dicthylene Glycol. -2. 5 46.8 77 47.6 Triethylene Glycol. 3. 0 48. 3 78 47. 5 Polyethylene Glycol MW 200 -6. 5 46. 4 77 48. 6 Polyethylene Glycol M.W.

300 6. 0 47. 9 74 47. 0 Polyethylene Glycol M.W.

400 5. 5 48. 7 73 4B. 8 Polyethylene Glycol M W.

-4. 5 48. 0 80 48. 8 "Carbon/ax 1000. 2.0 48 0 59 48.0 Carbowax" 1500. 4. 0 46. 8 78 48. 4 Carbowax" 4000..-- +4.0 40. G 74 48. 6 Carbowax" 6000.... +3. 5 47. 5 80 49. 8 Propylene Glycol +3. 5 46. 7 03 46. 9 Polypropylene Glycol M.W. 400 +3.0 48.8 81 48.3 Polypropylene Glycol M.W.

750 +20. 0 46. 0 87 47. 0 Pluronic L44----- +11. 0 47. 6 76 40. 0 Pluronic" F-68 +15. 0 47. 8 65 40. 2

The data of Table 5 show inter alia that not all polyglycols are effective in reducing the critical solution temperature of detergent solutions made from sodium keryl benzene sulfonate in admixture with a minor amount of sodium toluene sulfonate. Thus, Pluronic L-44 has a negligible effect in further increasing the solubility (lowering the criticial solution temperature) of such solutions, while Pluronic F-68 and polypropylene glycol having a molecular weight of about 750 actually decrease the solubility of the detergent.

It will be realized by those skilled in the art that changes may be made in the compositions and methods of preparing them hereinbefore described without departing from the scope of the invention. Thus, in place of the higher alkylbenzene sulfonic acid salts employed in the above specific examples, one or more other watersoluble salts of higher alkylbenzene sulfonic acids of the class hereinbefore disclosed may be employed: and, in place of the salts of benzene sulfonic acids of low molecular weight and diols employed in the specific examples, one or a mixture of other water-soluble salts of alkylbenzene sulfonic acids of low molecular weight and diols of the classes hereinbefore disclosed may be employed. Similarly, the proportions of the higher alkylbenzene sulfonate and benzene sulfonate of low molecular weight and diol may be varied, as hereinbefore disclosed.

The conditions of sulfonation also may be varied in the manner known in the art, as illustrated by the patents referred to above. Thus, in carrying out the sulfonation of the higher alkylbenzene, or mixture of higher alkylbenzene and benzene or lower alkylbenzene, others of the usual sulfonating agents may be employed; as, for example, sulfuric acid, chlorosulfonic acid, oleum of 5 various strengths, sulfur trioxide, stabilized sulfur trioxide, etc.

The neutralization of the sulfonic acids and/or conversion to water-soluble salts need not be carried out in the manner disclosed in the specific examples, but can be elfected in any other of the usual ways illustrated in the patents referred to above, and USP 2,652,427.

As employed herein, the expression detergent solution means that the product is a clear, stable liquid having the visible appearance and characteristics of a solution; it does not necessarily mean that all components are in a state of molecular dispersion, rather than in the form of micelles or fine colloid particles.

We claim:

1. A concentrated aqueous detergent composition having the appearance and characteristics of a solution and consisting essentially of water and solutes, said solutes consisting essentially, by weight of the aqueous detergent composition, of about 30% of a mixture of the sodium salts of higher alkylbenzene sulfonic acids having an average of 12 to 16 non-aromatic carbon atoms, about 5% of the sodium salt of toluene sulfonic acid, and 1% to 2% of a polyethylene glycol selected from the group consisting of diethylene glycol, triethylene glycol and mixtures of polyethylene glycols which have an average molecular weight of 200 to 1250 and a major proportion of which have molecular weights within said range.

2. A concentrated liquid aqueous detergent composition as defined in claim 1, wherein the mixture of sodium salts of higher alkylbenzene sulfonic acids is the sodium salt of a kerylbenzene sulfonic acid.

3. A concentrated liquid aqueous detergent composition as defined in claim 1, wherein the mixture of the sodium salts of higher alkylbenzene sulfonic acids and the sodium salt of toluene sulfonic acid have been obtained from a mixture of sulfonic acids resulting from I:

the co-sulfonation of a kerylbenzene and toluene, and

the polyethylene glycol is a mixture of polyethylene A glycols having an average molecular weight of about 400.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Oarbowax, Carbide &- Carbon Corp, 16 page boo let, 1946.

Harris: American Perfumer and Essential Oil Review, vol. 48, No. 11, November 1946, pages 54-56.

Great Britain May 4, 1955'

Claims (1)

1. A CONCENTRATED AQUEOUS DETERGENT COMPOSITION HAVING THE APPEARANCE AND CHARACTERISTICS OF A SOLUTION AND CONSISTING ESSENTIALLY OF WATER AND SOLUTES, SAID SOLUTES CONSISTING ESSENTIALLY, BY WEIGHT OF THE AQUEOUS DETERGENT COMPOSITION, OF ABOUT 30% OF A MIXTURE OF THE SODIUM SALTS OF HIGHER ALKYLBENZENE SULFONIC ACIDS HAVING AN AVERAGE OF 12 TO 16 NON-AROMATIC CARBON ATOMS, ABOUT 5% OF THE SODIUM SALT OF TOLUENE SULFONIC ACID, AND 1% TO 2% OF A POLYETHYLENE GLYCOL SELECTED FROM THE GROUP CONSISTING OF DIETHYLENE GYLCOL, TRIETHYLENE GLYCOL AND MIXTURES OF POLYETHYLENE GLYCOLS WHICH HAVE AN AVERAGE MOLECULAR WEIGHT OF 200 TO 1250 AND A MAJOR PROPORTION OF WHICH HAVE MOLECULAR WEIGHTS WITHIN SAID RANGE.