US3651119A - Sulfur-linked linear alkyl vicinal disulfates - Google Patents

Abstract

DETERGENT ACTIVE MATERIALS WHICH ARE EFFECTIVE IN THE ABSENCE OF PHOSPHATE BUILDERS COMPRISE SULFUR-LINKED LINEAR ALKYL VICINAL DISULFATES OF THE FORMULA:

R-CH(-R1)-Y-CH2-CH(-O-SO3-X)-CH2-O-SO3-X

IN WHICH Y IS

-S-, -SO-, OR -SO2-

R AND R1 ARE HYDROGEN OR ALKYL RADICALS HAVING A TOTAL OF FROM 9 TO 23 CARBON ATOMS, AND X IS HYDROGEN OR A WATER-SOLUBLE SALT-FORMING CATION.

Description

United States Patent 3,651,119 SULFUR-LINKED LINEAR ALKYL VICINAL DISULFATES Robert G. Anderson, San Rafael, Califi, assignor to Chevron Research Company, San Francisco, Calif. No Drawing. Filed Aug. 5, 1970, Ser. No. 62,233 Int. Cl. C07c 141/02 US. Cl. 260-458 4 Claims ABSTRACT OF THE DISCLOSURE Detergent active materials which are effective in the absence of phosphate builders comprise sulfur-linked linear alkyl vicinal disulfates of the formula:

R and R are hydrogen or alkyl radicals having a total of from 9 to 23 carbon atoms, and X is hydrogen or a water-soluble salt-forming cation.

BACKGROUND OF THE INVENTION This invention is concerned with sulfur-linked linear alkyl vicinal disulfates which are effective as heavy duty detergent active material.

Increased concern over water pollution has produced significant changes in household detergents. Initially, major emphasis has been placed on producing biodegradable surface-active components for detergents. The shift to linear surface-active materials, including linear alkylbenzene sulfonate (LAS) and alpha-olefin sulfonates, etc., has reduced pollution attributed to nonbiodegradability.

However, the above-mentioned surface-active materials are inadequate in terms of soil removal in the absence of phosphate builders. Increasing evidence appears to indicate that phosphates contribute to the growth of algae in the nations streams and lakes. This algae growth poses a serious pollution threat to the maintenance of clear, good domestic :water supplies.

Consequently, there has developed a need for detergent active materials which will function successfully in the absence of phosphate builders. Recently, certain nonphosphate building materials have been proposed as replacements for the phosphates. Thus, materials such as the polysodium salts of nitrilotriacetic acid, ethylene diamine tetraacetic acid, copolymers of ethylene and maleic acid, and similar polycarboxylic materials have been proposed as builders. These materials, however, when employed with conventional detergent actives such as LAS, have, for one reason or another, not proved to be quite as effective as phosphates in detergent formulations. For example, some of the materials have proven to be insufiiciently biodegradable to meet present and anticipated requirements.

It is therefore desirable to provide compounds which are effective as detergent active materials in the absence of phosphate builders and are also sufficiently biodegradable that their use results in contributing neither foam producers nor phosphates to the water supply.

SUMMARY OF THE INVENTION Effective heavy duty detergent compositions which may Patented Mar. 21, 1972 be formulated without the necessity of phosphate builders are provided. These formulations employ as detergent active materials sulfur-linked linear alkyl vicinal disulfates of the formula:

in which Y is R and R are hydrogen or alkyl radicals having a total of from 9 to 23 carbon atoms, and X is hydrogen or a water-soluble salt-forming cation. In a preferred form Yis and X is an alkali metal cation. It is also preferred that the sum of the carbon atoms in R and R be in the range of 13 to 19 carbon atoms.

The compounds of this invention do not require the presence of a phosphate builder to achieve good detergency. They achieve excellent detergency with such materials as the sodium salts of nitrilotriacetic acid and polycarboxylates such as ethylene-maleic anhydride copolymer. The materials, however, may be employed in the absence of any builder.

DESCRIPTION OF PREFERRED EMBODIMENTS The salt-forming cation X may be any of numerous materials such as alkali metal, alkaline earth metal, ammonium, or various organic cations. Examples of suitable organic cations include amino materials such as those of the following structure:

NH HOH CH OH) 2 or HN+ (CH CH OH) 3 The alkali metal cations are preferred, and sodium ions are particularly preferred.

The alkyl groups represented by R and R are, as previously noted, linear, although the presence of a random methyl radical upon the linear chain, for example, may not adversely affect the performance of the compound. Alkyl radicals representative of R and R include hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, heneicosyl, and docosyl. Heptadecyl, octadecyl, nonadecyl, eicosyl, and heneicosyl groups are preferred. In a preferred form the materials are formed by the reaction of thioglycerol wtih an alpha olefin and thus one or the other of R and R will be hydrogen.

The detergent active compounds of this invention are preferably prepared by reacting a linear monoolefin, preferably an alpha olefin, with thioglycerol giving a compound having two vicinal hydroxy groups. The hydroxy groups are then sulfated by conventional techniques giving a compound containing two sulfate groups and a sulfide linkage in the backbone. This compound, while being an adequate detergent, is sensitive to bleaching and in the preferred embodiment the sulfide prior to sulfation is oxidized to a sulfoxide or a sulfone or a mixture thereof. The products then obtained by sulfation are excellent detergents and are bleach stable.

The reaction of the olefin and the thioglycerol is accomplished by simply heating the materials together followed by recrystallization from conventional solvents such as ethanol or benzene. The sulfation of the dioxy compound is efiected by conventional sulfation techniques employing sulfur trioxide, chlorosulfonic acid, oleum,

3 sulfuric acid, etc., in a ratio of at least 2 mols of sulfating agent-per mol of diol. Ratios of from 2 to 10 are preferred. When it is desired to oxidize the sulfide group prior to sulfation, this is accomplished again by conventional techniques employing as oxidizing agents hydrogen peroxide, metal hypohalites, etc.

The following examples illustrate the preparation of the compounds of this invention.

EXAMPLE 1 Addition of thioglycerol to l-hexadecene A 500 ml. flask was charged with 112 g. (0.5 mol) of l-hexadecene, 71.5 g. (0.6 mol) of thioglycerol, and 100 ml. of ethanol. The mixture was placed upon a hot plate and heated overnight at 50-70 C. The mixture, originally in two layers, had become homogenous. It was allowed to cool to room temperature and then further cooled with ice. The solid product in the flask was removed by filtration and recrystallized from ethanol. The product was dried in a 50 C. oven overnight and gave a yield of 126 g. of a white solid which melted at 71-72 C. and by IR analysis showed two types of -OH absorption and no remaining olefin bonds.

EXAMPLE 2 Addition of thioglycerol to l-eicosene The procedure of Example 1 was followed employing 140 g. (0.5 mol) of l-eicosene instead of hexadecene. After recrystallization from ethanol there was obtained 166.6 g. (85.9% yield) of a white solid which showed by IR analysis two types of OH absorption and the presence of a small amount of alpha olefin. The product was recrystallized from benzene to give a white solid, melting point 8283.5 C., an IR analysis of which showed no remaining olefin bonds.

EXAMPLE 3 Addition of thioglycerol to l-docosene The procedure of Example 1 was followed employing 154 g. (0.5 mol) of l-docosene. The product recrystallized from benzene was 183 g. (88% yield) of a white solid having a melting point of 87-88 C.

EXAMPLE 4 Oxidation of eicosene-thioglycerol adduct 15.1 g. (0.039 mol) of the product of Example 2 and 60 ml. of glacial acetic acid were placed in a 125 ml. flask equipped with a magnetic stirrer. A thermometer was inserted and 10.5 ml. (0.084 mol) of 30.6% H was added slowly and with stirring. The maximum temperature reached without the application of external heat was 50 C. The temperature was raised to 80 C. and maintained for 1% hours. The mixture was cooled in ice and the product collected by suction. The white solid thus obtained was recrystallized from benzene to give 14.7 g. (90.0% yield) of product as white needles, melting point 112-l13 C., whose IR spectra showed a strong band at 1120 cm.- (-SO and nothing at about 1000 cmr (--SO-).

EXAMPLE 5 lSulfation of oxidized hexadecene-thioglycerol adduct with 50;,

276 mg. (0.6 mmol) of a sulfone-containing material prepared according to the procedure of Example 4 from the product of Example 1 was placed in a 100 ml. stoppered graduated cylinder containing ml. of CCL, and a magnetic stirring bar. The mass was heated to dissolve, then stirred and placed in an ice bath. The precipitate was uniformly fine. After flushing with N 0.1 ml. of S0 was added dropwise to the cold suspension. The mixture turned yellow and dissolvecLIhe cylinder was removed :from the ice and an additional 0.1 ml. of S0 4 was added dropwise. The color darkened. A 1 ml. sample was titrated with Hyamine showing the presence of 1.9 sulfate groups per molecule. The CC], was removed from the remainder of the solution, water was carefully added, and the whole was neutralized to a pH of 10 (pH meter) with NaOH solution.

EXAMPLE 6 Sulfation of sulfoxide-containing-octadecene thioglycerol adduct 0.5 g. of an adduct of l-octadecene with thioglycerol prepared according to the procedure of Example 1 and oxidized to contain one sulfoxide group per molecule was placed in a 250 ml. beaker and dissolved in 40 ml. of dry methylene chloride. After cooling the mixture to 10 C., 1.0 ml. of chlorosulfonic acid was slowly added by submerging the tip of an eyedropper containing the acid below the surface of the well agitated solution. The resulting solution was allowed to stand at ambient conditions for five minutes. The pH was adjusted to 8-9 with dilute sodium hydroxide. The solvent was removed by gentle warming and the residue diluted to 10 ml.

EXAMPLE 7 Sulfation of eico'sene-thioglycerol adduct with chlorosulfonic acid A 125 ml. Erlenmeyer flask was charged with 0.5 g. (51.29 mmoles) of the product of Example 2 and 40 ml. of dry diethyl ether. After cooling the mixture to 10 C., 1.0 ml. of chlorosulfonic acid was slowly added by submerging the tip of an eyedropper containing the acid below the surface of the well agitated ether solution. The resulting solution was allowed to stand at ambient conditions for five minutes. The pH was adjusted to 8-9 with dilute sodium hydroxide. The solvent was removed by gentle warming and the residue diluted to ml.

Detergency of the compounds of the present invention is measured by their ability to remove natural sebum soil from cotton cloth. By this method, small swatches of cloth, soiled by rubbing over face and neck, are washed with test solutions of detergents in a miniature laboratory washer. The quantity of soil removed by this washing procedure is determined by measuring the reflectances of the new cloth, the soiled cloth, and the washed cloth, the results being expressed as percent soil removal. Because of variations in degree and type of soiling, in water and in cloth, and other unknown variables, the absolute value of percent soil removal is not an accurate measure of detergent effectiveness and cannot be used to compare various detergents. Therefore, the art has developed the method of using relative detergency ratings for comparing detergent eifectiveness.

The relative detergency value is obtained by comparing and correlating the reflectance value results from the test solution with the results from two defined standard solutions.

The two standard solutions are selected to represent a detergent formulation exhibiting relatively high detersive characteristics and a formulation exhibiting relatively low detersive characteristics.

-By testing experimental solutions against the two standardized solutions, using different portions of the same soiled cloth, the results can be accurately correlated. The two standard solutions were prepared for the following detergent formulations:

Formulation for the low detersive standard (Control A) Ingredient: Weight percent Formulation for the high detersive standard (Control B) Ingredient: Weight percent The standard exhibiting high-detersivc characteristics was prepared by dissolving a relatively large amount of the above formulation (Control B) (2.0 g.) in 1 liter of 300 p.p.m. hard water (calculated as calcium carbonate and /3 magnesium carbonate). The low detersive standard contained a relative low concentration of the formula (Control A) (1.0 g.) dissolved in 1 liter of 300 p.p.m. water (same basis).

The miniature laboratory washer used was so constructed that the two standard formulations and two test formulations could he used to wash different parts of the same swatch. This arrangement ensured that all four formulations were working on identical soil (natural facial soil). Relative detergency (RD) values were calculated from soil removals (SR), according to the equation:

Percent SR -Percent. SR A RD=2+4 Percent SR Percent SR m, A

lated with additional compatible ingredients being optionally incorporated to enhance the detergent properties. Such materials may include but are not limited to anticorrosion, antiredeposition, bleaching and sesquestering agents, and certain organic and inorganic alkali metal and alkaline earth metal salts such as in organic sulfates, carbonates, or borates. Also nonphosphate builders may be included in the composition. Examples of these builders are the sodium salts of nitrilotriacetic'acid, ethylene diamine tetraacetic acid, and ethylene maleic acid copolymers, etc. Also small quantities of phosphate builders may be included although, of course, they are no necessary for elfective detergency.

While the character of this invention has been described in detail with numerous examples, this has been done by way of illustration only and without limitation of the invention. It will be apparent to those skilled in the art that modifications and variations of the illustrative examples may be made in the practice of the invention within the scope of the following claims.

I claim:

1. A compound of the formula:

R and R are hydrogen or alkyl radicals having a total of from 9 to 23 carbon atoms, and X is hydrogen or a member of the group consisting of alkali metal, alkaline earth metal, ammonium, NH +(CH CH OH) and NH+(CH CH OH) cations.

RELATIVE DETERGENOY OF ALKYL VICINAL DISULFATES Relative detergency ratings in 50 p.p.m. 1120' Test materials Sultoxldes Sulfones NTA Carbon atoms Compound tested Cone. cone. in R andgRi 0.1% cone. 0.2% conc. 0.1% cone. 0.2% cone.

The relative detergency rating for linear alkylbenzene sulfonate (LAS) was 2.9 at 0.1% and 3.9 at 0.2% concentration (50 p.p.m. water hardness). The rating for an LAS (20%)lsodium triphosphate conventional built detergent was 5.8 at 0.1% and 6.1 at 0.2% concentration p.p.m. water hardness). These materials 'were tested in formulations containing 7% sodium silicate, 1% carboxymethylcellulose, 8% water, the indicated amounts of LAS and phosphate, and sufficient sodium sulfate to give 100%.

The sulfur-linked linear alkyl vicinal disulfates may be employed in combination with other detergent active materials. They are particularly effective with other dianionic materials, examples of which include linear alkyl and alkenyl disulfates and disulfonates. A particularly useful class of materials for use in detergent active combinations is that of linear 2-alkenyl or linear 2-alkyl 1,4- butane diol disulfates in which the alkenyl or alkyl groups contain from 15 to 20 carbon atoms.

In employing the detergent active materials of this invention in detergent compositions, they may be formu- UNITED STATES PATENTS 2,645,659 7/ 1953 Morris et al 260-458 X FOREIGN PATENTS 6709714 l/ 1968 Netherlands 260-458 LEON ZITVER, Primary Examiner L. B. DE CRESCENTE, Assistant Examiner US. Cl. X.R. 252161