CA1065888A - Method for the production of bleached, low-sultone olefin sulfonates - Google Patents
Method for the production of bleached, low-sultone olefin sulfonatesInfo
- Publication number
- CA1065888A CA1065888A CA264,088A CA264088A CA1065888A CA 1065888 A CA1065888 A CA 1065888A CA 264088 A CA264088 A CA 264088A CA 1065888 A CA1065888 A CA 1065888A
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- Canada
- Prior art keywords
- bleaching
- process according
- olefin
- content
- sultone
- Prior art date
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C303/00—Preparation of esters or amides of sulfuric acids; Preparation of sulfonic acids or of their esters, halides, anhydrides or amides
- C07C303/42—Separation; Purification; Stabilisation; Use of additives
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C309/00—Sulfonic acids; Halides, esters, or anhydrides thereof
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- Organic Chemistry (AREA)
- Detergent Compositions (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
METHOD FOR THE PRODUCTION OF
BLEACHED, LOW-SOLTONE OLEFIN SULFONATES
Abstract of the Disclosure Aqueous solutions of alkali metal C8-22 .alpha.-olefin sulfonates of light color and of low sultone content are pre-pared rapidly and at moderate temperatures by:
(a) reacting a C8-22 .alpha.-olefin with gaseous sulfur trioxide thereby forming a crude sulfonation product mixture containing C8-22 olefin sulfonic acids,with a content of sultones, (b) bleaching said crude sulfonation product mixture at 30°C to 80°C for 10 to 60 minutes with an aqueous alkaline bleaching solution at a pH of at least 8, (c) heating said diluted bleached sulfonation product mixture containing excess alkali to a temperature of from 140°C to 170°C until the sultone content of said sulfonation product mixture is less than 100 ppm and (d) recovering said alkali metal C8-22 .alpha.-olefin sulfates of light color and of low sultone content. A decrease in the sultone content from as much as 650,000 ppm to less than 50 ppm is possible by the method.
- A -
BLEACHED, LOW-SOLTONE OLEFIN SULFONATES
Abstract of the Disclosure Aqueous solutions of alkali metal C8-22 .alpha.-olefin sulfonates of light color and of low sultone content are pre-pared rapidly and at moderate temperatures by:
(a) reacting a C8-22 .alpha.-olefin with gaseous sulfur trioxide thereby forming a crude sulfonation product mixture containing C8-22 olefin sulfonic acids,with a content of sultones, (b) bleaching said crude sulfonation product mixture at 30°C to 80°C for 10 to 60 minutes with an aqueous alkaline bleaching solution at a pH of at least 8, (c) heating said diluted bleached sulfonation product mixture containing excess alkali to a temperature of from 140°C to 170°C until the sultone content of said sulfonation product mixture is less than 100 ppm and (d) recovering said alkali metal C8-22 .alpha.-olefin sulfates of light color and of low sultone content. A decrease in the sultone content from as much as 650,000 ppm to less than 50 ppm is possible by the method.
- A -
Description
~1.06513~
Related Art Surface-active ~-olefin sulfonates are customarily produced technically by sulfonating linear ~-olefins having 8 to 22 carbon atoms at temperatures of between 20C to 100C
with gaseous sulfur trioxide which is diluted with inert gases, such as air or nitrogen, to a concentration of 0.5% to 20~ by volume. The sultones formed by an addition reaction to the alkene sulfonic acids formed during sulfonation are hydrolyzed subsequent to sulfonation in which case, usually excess alkali and temperatures of between 80~C and 200C, especially 100C, are employed. The sulfonation products and consequently the sulfonates so produced are, however, too dark in color for most purposes, and therefore they are usually cleaned or bleached before being used further.
According to British Patent Specification No. 983, 056, bleaching is effected with hy~lrogen peroxide, alkali metal chlorites or alkali ~etal hypochlorites or even the components for for~ing these co~pounds, the bleaching being effected before, during or subsequent to the hydrolysis of the sultones. The bleaching may be performed either on the crude acid sulfonation product or on the hydrolyzate which may be acidic, alkaline or neutral. Particularly good bleaching is obtained when the bleaching step is performed subsequent to alkaline hydrolysis, and ~Jhen hypochlorites or chlorites are used for the purpose.
It has now been shown that the olefin sulfonates produced in this manner still contain some quantities of sul-tones. However, after Druckrey et al ascertained carcenogenic properties in propane sultone in the Cancer Research ~ournal, 75, 69-84 (1970), serious toxicological objections to sultone-containing olefin sulfonates or their use in detergents and wash liquids have been raised recently. These objections ph/
~6588~
. :.
are exclusively directed against the sultone admixtures since low-sultone ~-oleEin sulfonates are of considerable :~
technical interest because of their good biodegradability, their comparatively favourable skin-compatibility, and their `
excellent cleaning properties. :~ ~
One current way of hydrolyzing the dif~icultly ~-saponifiable sultones completely is to make the hydrolysis te~perature as high as possible, such as by operating under pressure at temperatures of above 170C to 180C. However, olefin sulfonates hydrolyzed in this temperature range are generally very dark in color, so that bleaching cannot be avoi-ded before they are used further. Unfortunately, however, ~ven an olefin sulfonate which has been hydrolyzed at appropriately high temperatures and has subsequently been bleached-still always has a remarkahly high-sultone content. .
Objects of the Invention An object of the present invention, therefore, is to develop a method which eliminat~s the disadvantages men~
tioned and makes it possible to produce an attracti.ve product 20 which, at .the same time, is toxicologically harmless. .:
Another object of the inYention is the development of a process for the production of a light-.colored olefin . .:
sulfonate having low sultone content .comprising the steps oi (a) reacting a C8-22 ~-olefin with from 1.0 to 1.5 mols of gaseous sulfur trioxide diluted with an inert gas to. a .
concentration of 0.5 to 20 by volume, t~ereby forming ~ .
a crude sulfonation product mixture comprising a ..
C8-22 olefin sulfonic acid, with a content of sultones, ..
(b) diluting said crude sulfonation product mixture to ::
a 5% to 80% by weight solution and bleaching said aqueous solution containing the crude sulfonation
Related Art Surface-active ~-olefin sulfonates are customarily produced technically by sulfonating linear ~-olefins having 8 to 22 carbon atoms at temperatures of between 20C to 100C
with gaseous sulfur trioxide which is diluted with inert gases, such as air or nitrogen, to a concentration of 0.5% to 20~ by volume. The sultones formed by an addition reaction to the alkene sulfonic acids formed during sulfonation are hydrolyzed subsequent to sulfonation in which case, usually excess alkali and temperatures of between 80~C and 200C, especially 100C, are employed. The sulfonation products and consequently the sulfonates so produced are, however, too dark in color for most purposes, and therefore they are usually cleaned or bleached before being used further.
According to British Patent Specification No. 983, 056, bleaching is effected with hy~lrogen peroxide, alkali metal chlorites or alkali ~etal hypochlorites or even the components for for~ing these co~pounds, the bleaching being effected before, during or subsequent to the hydrolysis of the sultones. The bleaching may be performed either on the crude acid sulfonation product or on the hydrolyzate which may be acidic, alkaline or neutral. Particularly good bleaching is obtained when the bleaching step is performed subsequent to alkaline hydrolysis, and ~Jhen hypochlorites or chlorites are used for the purpose.
It has now been shown that the olefin sulfonates produced in this manner still contain some quantities of sul-tones. However, after Druckrey et al ascertained carcenogenic properties in propane sultone in the Cancer Research ~ournal, 75, 69-84 (1970), serious toxicological objections to sultone-containing olefin sulfonates or their use in detergents and wash liquids have been raised recently. These objections ph/
~6588~
. :.
are exclusively directed against the sultone admixtures since low-sultone ~-oleEin sulfonates are of considerable :~
technical interest because of their good biodegradability, their comparatively favourable skin-compatibility, and their `
excellent cleaning properties. :~ ~
One current way of hydrolyzing the dif~icultly ~-saponifiable sultones completely is to make the hydrolysis te~perature as high as possible, such as by operating under pressure at temperatures of above 170C to 180C. However, olefin sulfonates hydrolyzed in this temperature range are generally very dark in color, so that bleaching cannot be avoi-ded before they are used further. Unfortunately, however, ~ven an olefin sulfonate which has been hydrolyzed at appropriately high temperatures and has subsequently been bleached-still always has a remarkahly high-sultone content. .
Objects of the Invention An object of the present invention, therefore, is to develop a method which eliminat~s the disadvantages men~
tioned and makes it possible to produce an attracti.ve product 20 which, at .the same time, is toxicologically harmless. .:
Another object of the inYention is the development of a process for the production of a light-.colored olefin . .:
sulfonate having low sultone content .comprising the steps oi (a) reacting a C8-22 ~-olefin with from 1.0 to 1.5 mols of gaseous sulfur trioxide diluted with an inert gas to. a .
concentration of 0.5 to 20 by volume, t~ereby forming ~ .
a crude sulfonation product mixture comprising a ..
C8-22 olefin sulfonic acid, with a content of sultones, ..
(b) diluting said crude sulfonation product mixture to ::
a 5% to 80% by weight solution and bleaching said aqueous solution containing the crude sulfonation
- 2 -ph/ ~
~6~38~
. . .
product mixture at 30C to 80C for 10 to 60 minutes at a pH of over 8 ~y the action of an inorganic bleaching agent equivalent to 0.5% to 5~ by weight~ based on the olefin sulfonate content, of NaOCl, selected from the group consisting of active oxygen bleaching agents and active chlorine bleaching agents, (c) heating said diluted bleached sulfonation product mix-ture containing excess alkali sufficient to give an alkaline pH after hydxolysis is completed, at a tempera-ture of from 140C to 170C for a time sufficient until the sultone content of the sulfonation product mixture is less than 100 ppm, and (d) recovering said light-colored olefin sulfonate having low-sultone content.
These and other objects of the invention will become more apparent as the description thereof proceeds.
Description of the Invenkion The present invention provides a method of producing light-colored low-sultone olefin sulfonates by reacting olefins containing 8 to 22 carbon atoms and a terminal double bond with 1.0 to 1.5 times the molar quantity of gaseous sulfur trioxide, diluted with inert gas to a concentration of 0.5~ to 20~ by volume, bleaching the sulfonation products with hydrogen perox-ide, alkali metal chlorites or alkali metal hypochlorites or the components forming these substances in situ and hydroly-~ing the sulfona~ion products, characterized in that the crude sulfonation products are bleached in aqueous-alkaline 5% to 80%
by weight solution at a temperature of 30C to 80C for a period of 10 to 60 minutes with a quantity of bleaching agent, which is, relative to the olefin sulfonate content, equivalent to 0.5% to 5% by weight of NaOCl in bleaching power, the mixture ph/~
~65~
., ~hereupon being heated to a temperature of 140~c to 170C, preferably 150C to 165C, in the presence of an excess quan-tity of alkali relative to the hydrolyzed end product, and being left at this temperature until the sultone content has dropped to less than 100 p.p. m., preferably below 50 p.p.m. ~-More particularly, the present invention involves a process for the production of a light-colored olefin sulfon-ate having low-sulton~ content comprising the steps of (a) reacting a C8-22 a-olefin with from 1.0 to 1.5 mols of gaseous sulfur trioxide diluted with an inert gas to a concentration of 0.5 to 20% by volume, thereby forming a crude sulfonation product mixture comprising a C8-22 olefin sulfonic acid, with a content of sultones, (b) diluting said crude sulfonation product mixture to a 5% to 80% by weight solution and bleaching said aqueous solution containing the crude sulfonation pro-duct mixture at 30C to 80C for 10 to 60 minutes at a pH of over 8 by the action of an inorganic bleaching agent equivalent to 0.5~ to 5% by weight, based on the olefin sulfonate content, of NaOCl, selected from the -group consisting of active oxygen bleaching agents and active chlorine bleaching agents, , (c) heating said diluted bleached sulfonation product mixture containing excess a ~ i suEEicient to ~ive an alkaline pH after h~drolysis ~s completed, at a tempera-ture of from 140~C to 170C for a time sufficient until the sultone content of the sulfonation product mixture `;
is less than 100 p.p.m., and (d) recovering said light-colored olefin sulfonate having low-sultone content.
In the sulfonation the amount of sulfur trioxide --reacted is preferably 1.05 to 1.15 mol per mol of the ~-olefin~
ph/
.
~06588~
-~ ~ The crude product of the sulfonation skep typically is composed of about 55% - 65% (averaging about 60~ of sultones, about 2% to 10% ~averaging about 5%) of disulfonic acids, and 30% - 40% ~averaging 35%) of monosulfonic acids.
The proportion of disulfonic acids increases with the amount of sulfur trioxide which is admitted as reagent. It is this mixture which is purified by the process of the present in-vention. The process of the present invention, however is applicable to sulfonation products containing as little as 100,000 ppm of sulfones.
Prefer~bly, in the above process, the bleaching is continued until the color of the solution remains substantially constant, i.e., un~îl the bleaching action of the bleaching component of the solution is substantially complete.
We have further ~ound that the sultone content can be decreased from above 650,000 p.p.m. to below 50 p.p.m.
with production of an olefin sulfonate of excellent light color sufficiently rapidly to permit performance of the process in continuous manner.
The first step (subsequent to the sulfonation of the olefin) of the method according to the invention is the alXalization of the cxude sulfonation product with aqueous alkali. The pH value of the solution thereby formed should be at le~st 8, and preferably should be 10 to 14, and should be maintained above 8 (and ~re~erably in the range of 10 to 14) during bleaching. The sulfonation product may be stirred into the aqueous alkali solution, and a sufficient excess of alkalis should be used so that the solution is alkaline at a pH of at least 8 after hydrolysis and bleaching (i.e., the amount of alkali should be in excess of the stoichiometrical)~ Another method which may be employed comprises adding initially only ph/-, .
~5~3~8 a portion of the total alkali needed and adding the remainder together with the bleaching agent. If preferred, the excess alkali needed for the ~sydrolysis of the sultones can be added after bleaching. The latter method, however, requires an additional step and is, therefore, less advantageous. Suit-able alkalis are the strongly alkaline alkali metal hydroxides, carbonates, silicates and phosphates. Preferably the alkali metal is sodium and potassium. Sodium hydroxide is preferred.
The concentration of the aqueous sodium hydroxide and the quantity of the water to be introduced, where appli-cabl~, with the bleaching agent, are such that the concentra-tion of ~se olefin sulfonate is 5~ to 80%, preferably ~0% to 60~, by weight.
The temperature during neutralization and subsequent ~ .
bleaching should not exceed 80C and the mixture should be cooled or precooled when aqueous sodium hydroxide or other exothermic alkali is added.
The second step in the method according -~o the in- ~`
vention comprises bleaching the alkalized sulfonation mix-~ ture. Any suitable water-soluble inorganic oxidizing bleach c~s be used which is stable at an alkali pH. Suitable bleach-ing agents for the purpose are active oxygen bleaches, such as hydrogen peroxide, sodium peroxide, peroxides producing per-hydrates and hydrogen peroxide ancl active chlorine bleaches, such as alkali met.al hypochlorites, alkali metal chlorites, chlorine, and chlorine dioxide, the latter two reactjng with the exce~s alkali to form alkali metal hypochlorites or chlor~
ites. Alkali hypochlorites or chlorine introduced into the alkaline mix~ture in gaseous orns or as aqueous chlorine solution, are preferably used because of their cheapness, absence of toxicity and effectiveness. In -the latter case, an appropriate cOnSUmptiGn of alkali is to be taken into consideration.
ph/`-.
658~8 Depending upon the degree of discoloration of thesubstrate and the amount of bleaching desired, in the~ case of hypochlorites, the quantity of bleaching agent added generally falls within the range of 0.5~ to 5~, and preferably 1~ to 3~, by weight, calculated as NaOCl based on the weight of sulfona- -tion product present. Other bleaching agents are added in equivalent amounts.
Bleaching is effected at temperatures of 30C to 80C, preferably 50C to 60C. In the preferred temperature range, the bleaching is substantially complete in 15 to 30 minutes. Higher tem~eratures result in slightly faster bleach-ing/ a~d lower temperatures require a slightly longer time.
It is advisable to stir the reaction mixture intensively during the bleaching treatment. As stated, the pH should be in excess of 8 during the bleaching. The necessary alkali can be added at the start of the bleaching step, or the minimum amount needed to adjust the solution to pH 8 can be added at the out-~set and the pH maintained above 8 hy periodic small additions.
It is preferable for the superalkalization and bleach-ing to be effected in a single step, whereby an aqueous sodiumhydroxide solution containing bleach~ng agent is used,the appropriate quantity of the acid sulfonation mixture is skirred in and the bleaching treatment is continued by stirring until the desired degree of lightness is reached or the precalculated quantity of bleaching agent is consumed.
For hydrolysis -- the third step in the method according to the in~ention -- the bleached sulfonation mixture containing excess alkali is heated in a pressure vessel to temperatures of 140C to 170C, pre~erably 150C to 165C, Hydrolysis is continued until the sultone content has dropped by at least 90%, i.e., to less than 100 ppm, preferably less ph/
~ 588~3 -`than 50 ppm, based on the weight of the solu~ion. D~pending upon the hydrolysis temperature chosen, only 10 to 30 minutes - -are needed there~or. About 25 minutes are needed as a rule at 150C, and only about 15 minutes are needed at 165C.
Longer hydrolysis times at higher temperatures should be avoided, since they do not notably improve the hydrolysis result and cause deterioration of color. The excess alkali used prior to hydrolysis should be such that the solution after hydrolysis has been completed is still alkaline, i.e., has a pH of at least 9, preferably 11 to 14. The addition of alkali to produce this resul-t is termed "superalkalization. 71 ~, ': ., The method may be carried out in batches or contin-uously, through in ~he latter case a diffusion apparatus fitted -with pumps, dosing means and feeding means is used and hydro-lysis is effected, for example, in a heated spiral tube, the diffusion being regulated so that the specified mean reaction times are observed.
After hydrolysis has been completed, the solution is cooled; pressure is released, and the solution is neutralized, preferably with sulfuric acid.
The resulting solution may be processed further immediately to form detergents, wash liquids or cleansers.
The sulfonates can be recovered in dry particulate free-flowing form by drum drying or, preferably, by spray-drying the solution~
The olefin sulfonates obtained are distin~uished by a light color and low sultone content. This sultone content is on average lower by the factor 100 (i.e., it is about 1%) of the sultone content of olefin sulfonates which have been hydrolyzed and bleached according to known methods. ~
The sultone content of the product can be determined -as follows: ;
10 ~rams of olefin sulfonate are dissolved in 100 ml ph/
.
~58138 .. ~ .
of a 1:1 water/ethanol mixture and are extracted with n-hexane.
The hexane fraction is removed and the hexane is allowed to evaporate. The residue is dissolved in chloroform and the resulting solution is poured into a chromatographic column charged with a weighed quantity of silica gel and the eluate is evaporated until the residue is dry.
The sultone contained in the residue may be deter-mined quantitatively by saponifying the sultone completely and performing a two-phase titration of the sulfonates thereby formed with hyamine solution (a quaternary ammonium cationic surfactant; see U.S. Patent No. 2,115,250) against a mixed indicator.
A quick qualitative determination is possible by thin-layer chromatography on silica gel and dyeing with 4~(4-nitrobenzyl)-pyridine.
The invention is further described by the examples which follow. These examples are best embodiments of the ..
invention and are not to be construea as limitative thereof.
EXAMPLES 1_TO 3 A linear C14-C18 olefin of which 80~ was of C16 chain length and wherein the double bonds were terminal was used as the starting material. It was continuously sulEonated in a thin-layer reactor with 1.1 mol of sulfur trioxide, which was present in 3% by volume dilution with air at a temperature of 32C. The extent of sulfonation (determined by saponification) was 95,7%.
Samples of this crude sulfonation mixture were hydro-lyzed and bleached under various conditions, as shown in the following table. Hydrolysis and bleaching were effected after the addition of 1.2 times the molar quantity of sodium hydroxide as a 30% aqueous solution. NaOCl was added as ph/
~,51~388 ~
bleach in the form of an aqueous solution containing 13~ active chlorine by weight. The bleaching was for 25 minutes at 60C~
(Hydrolysis and bleaching in at acid pH values were Qmitted since this procedure produces products which are distinctly darker in color and are, therefore, less useful). The pH
value of the solution was 14 (at 20C) during bleaching and ;~
also after the conclusion of hydrolysis. ,-~
The sultone content of the resulting solutions was determined quantitatively by the method described above. The color values of the solutions were determined in a 4" tube by use of the Lovibond tintometer after dilution of the solutions to a sulfonic content of 5% by weight.
The comparative tests are designated by letters.
The examples which illustrate the present invention are desig~
nated by numbers. Test series A utilizes unbleached sulfonates.
Test series B utilizes sulfonates bleached after hydrolysis.
Test series C utilizes sulfonates bleached prior to hydrolysis, and test series D utilized sulfonates simultaneously hydrolyzed and bleached. One solution was treated for 3 hours at 100C
and the other was treated for 10 minutes at 180c.
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The olefin sulfonate solutions produced by the pro-cess of the present invention are distinguished by a sultone content of a maximum of 50 p.p.m. and by Lovibond color values of less than 3 for yellow, less than 0.4 for red, and 0 for blue. Solutions produced by other processes are unacceptably dark in color or have too high z sultone content or have both disadvantages.
The results show that the above process is capable ~
of rapidly decreasing the sultone content of the solution by -more than 98% with production of a very light colored solution.
The procedure of Example 3 is repeated except that the sodium hypochlorite solution added is replaced by aqueous hydrogen peroxide solution of equivalent bleaching strength.
The results are substantially the same.
The preceding specific embodiments are illustrative of the practice of the invention. It is to be understood, however, that other expedients known to those skilled in the art, or disclosed herein, may be employed without departing from the spirit of the invention or the scope of the appended claims ph/~r.
~6~38~
. . .
product mixture at 30C to 80C for 10 to 60 minutes at a pH of over 8 ~y the action of an inorganic bleaching agent equivalent to 0.5% to 5~ by weight~ based on the olefin sulfonate content, of NaOCl, selected from the group consisting of active oxygen bleaching agents and active chlorine bleaching agents, (c) heating said diluted bleached sulfonation product mix-ture containing excess alkali sufficient to give an alkaline pH after hydxolysis is completed, at a tempera-ture of from 140C to 170C for a time sufficient until the sultone content of the sulfonation product mixture is less than 100 ppm, and (d) recovering said light-colored olefin sulfonate having low-sultone content.
These and other objects of the invention will become more apparent as the description thereof proceeds.
Description of the Invenkion The present invention provides a method of producing light-colored low-sultone olefin sulfonates by reacting olefins containing 8 to 22 carbon atoms and a terminal double bond with 1.0 to 1.5 times the molar quantity of gaseous sulfur trioxide, diluted with inert gas to a concentration of 0.5~ to 20~ by volume, bleaching the sulfonation products with hydrogen perox-ide, alkali metal chlorites or alkali metal hypochlorites or the components forming these substances in situ and hydroly-~ing the sulfona~ion products, characterized in that the crude sulfonation products are bleached in aqueous-alkaline 5% to 80%
by weight solution at a temperature of 30C to 80C for a period of 10 to 60 minutes with a quantity of bleaching agent, which is, relative to the olefin sulfonate content, equivalent to 0.5% to 5% by weight of NaOCl in bleaching power, the mixture ph/~
~65~
., ~hereupon being heated to a temperature of 140~c to 170C, preferably 150C to 165C, in the presence of an excess quan-tity of alkali relative to the hydrolyzed end product, and being left at this temperature until the sultone content has dropped to less than 100 p.p. m., preferably below 50 p.p.m. ~-More particularly, the present invention involves a process for the production of a light-colored olefin sulfon-ate having low-sulton~ content comprising the steps of (a) reacting a C8-22 a-olefin with from 1.0 to 1.5 mols of gaseous sulfur trioxide diluted with an inert gas to a concentration of 0.5 to 20% by volume, thereby forming a crude sulfonation product mixture comprising a C8-22 olefin sulfonic acid, with a content of sultones, (b) diluting said crude sulfonation product mixture to a 5% to 80% by weight solution and bleaching said aqueous solution containing the crude sulfonation pro-duct mixture at 30C to 80C for 10 to 60 minutes at a pH of over 8 by the action of an inorganic bleaching agent equivalent to 0.5~ to 5% by weight, based on the olefin sulfonate content, of NaOCl, selected from the -group consisting of active oxygen bleaching agents and active chlorine bleaching agents, , (c) heating said diluted bleached sulfonation product mixture containing excess a ~ i suEEicient to ~ive an alkaline pH after h~drolysis ~s completed, at a tempera-ture of from 140~C to 170C for a time sufficient until the sultone content of the sulfonation product mixture `;
is less than 100 p.p.m., and (d) recovering said light-colored olefin sulfonate having low-sultone content.
In the sulfonation the amount of sulfur trioxide --reacted is preferably 1.05 to 1.15 mol per mol of the ~-olefin~
ph/
.
~06588~
-~ ~ The crude product of the sulfonation skep typically is composed of about 55% - 65% (averaging about 60~ of sultones, about 2% to 10% ~averaging about 5%) of disulfonic acids, and 30% - 40% ~averaging 35%) of monosulfonic acids.
The proportion of disulfonic acids increases with the amount of sulfur trioxide which is admitted as reagent. It is this mixture which is purified by the process of the present in-vention. The process of the present invention, however is applicable to sulfonation products containing as little as 100,000 ppm of sulfones.
Prefer~bly, in the above process, the bleaching is continued until the color of the solution remains substantially constant, i.e., un~îl the bleaching action of the bleaching component of the solution is substantially complete.
We have further ~ound that the sultone content can be decreased from above 650,000 p.p.m. to below 50 p.p.m.
with production of an olefin sulfonate of excellent light color sufficiently rapidly to permit performance of the process in continuous manner.
The first step (subsequent to the sulfonation of the olefin) of the method according to the invention is the alXalization of the cxude sulfonation product with aqueous alkali. The pH value of the solution thereby formed should be at le~st 8, and preferably should be 10 to 14, and should be maintained above 8 (and ~re~erably in the range of 10 to 14) during bleaching. The sulfonation product may be stirred into the aqueous alkali solution, and a sufficient excess of alkalis should be used so that the solution is alkaline at a pH of at least 8 after hydrolysis and bleaching (i.e., the amount of alkali should be in excess of the stoichiometrical)~ Another method which may be employed comprises adding initially only ph/-, .
~5~3~8 a portion of the total alkali needed and adding the remainder together with the bleaching agent. If preferred, the excess alkali needed for the ~sydrolysis of the sultones can be added after bleaching. The latter method, however, requires an additional step and is, therefore, less advantageous. Suit-able alkalis are the strongly alkaline alkali metal hydroxides, carbonates, silicates and phosphates. Preferably the alkali metal is sodium and potassium. Sodium hydroxide is preferred.
The concentration of the aqueous sodium hydroxide and the quantity of the water to be introduced, where appli-cabl~, with the bleaching agent, are such that the concentra-tion of ~se olefin sulfonate is 5~ to 80%, preferably ~0% to 60~, by weight.
The temperature during neutralization and subsequent ~ .
bleaching should not exceed 80C and the mixture should be cooled or precooled when aqueous sodium hydroxide or other exothermic alkali is added.
The second step in the method according -~o the in- ~`
vention comprises bleaching the alkalized sulfonation mix-~ ture. Any suitable water-soluble inorganic oxidizing bleach c~s be used which is stable at an alkali pH. Suitable bleach-ing agents for the purpose are active oxygen bleaches, such as hydrogen peroxide, sodium peroxide, peroxides producing per-hydrates and hydrogen peroxide ancl active chlorine bleaches, such as alkali met.al hypochlorites, alkali metal chlorites, chlorine, and chlorine dioxide, the latter two reactjng with the exce~s alkali to form alkali metal hypochlorites or chlor~
ites. Alkali hypochlorites or chlorine introduced into the alkaline mix~ture in gaseous orns or as aqueous chlorine solution, are preferably used because of their cheapness, absence of toxicity and effectiveness. In -the latter case, an appropriate cOnSUmptiGn of alkali is to be taken into consideration.
ph/`-.
658~8 Depending upon the degree of discoloration of thesubstrate and the amount of bleaching desired, in the~ case of hypochlorites, the quantity of bleaching agent added generally falls within the range of 0.5~ to 5~, and preferably 1~ to 3~, by weight, calculated as NaOCl based on the weight of sulfona- -tion product present. Other bleaching agents are added in equivalent amounts.
Bleaching is effected at temperatures of 30C to 80C, preferably 50C to 60C. In the preferred temperature range, the bleaching is substantially complete in 15 to 30 minutes. Higher tem~eratures result in slightly faster bleach-ing/ a~d lower temperatures require a slightly longer time.
It is advisable to stir the reaction mixture intensively during the bleaching treatment. As stated, the pH should be in excess of 8 during the bleaching. The necessary alkali can be added at the start of the bleaching step, or the minimum amount needed to adjust the solution to pH 8 can be added at the out-~set and the pH maintained above 8 hy periodic small additions.
It is preferable for the superalkalization and bleach-ing to be effected in a single step, whereby an aqueous sodiumhydroxide solution containing bleach~ng agent is used,the appropriate quantity of the acid sulfonation mixture is skirred in and the bleaching treatment is continued by stirring until the desired degree of lightness is reached or the precalculated quantity of bleaching agent is consumed.
For hydrolysis -- the third step in the method according to the in~ention -- the bleached sulfonation mixture containing excess alkali is heated in a pressure vessel to temperatures of 140C to 170C, pre~erably 150C to 165C, Hydrolysis is continued until the sultone content has dropped by at least 90%, i.e., to less than 100 ppm, preferably less ph/
~ 588~3 -`than 50 ppm, based on the weight of the solu~ion. D~pending upon the hydrolysis temperature chosen, only 10 to 30 minutes - -are needed there~or. About 25 minutes are needed as a rule at 150C, and only about 15 minutes are needed at 165C.
Longer hydrolysis times at higher temperatures should be avoided, since they do not notably improve the hydrolysis result and cause deterioration of color. The excess alkali used prior to hydrolysis should be such that the solution after hydrolysis has been completed is still alkaline, i.e., has a pH of at least 9, preferably 11 to 14. The addition of alkali to produce this resul-t is termed "superalkalization. 71 ~, ': ., The method may be carried out in batches or contin-uously, through in ~he latter case a diffusion apparatus fitted -with pumps, dosing means and feeding means is used and hydro-lysis is effected, for example, in a heated spiral tube, the diffusion being regulated so that the specified mean reaction times are observed.
After hydrolysis has been completed, the solution is cooled; pressure is released, and the solution is neutralized, preferably with sulfuric acid.
The resulting solution may be processed further immediately to form detergents, wash liquids or cleansers.
The sulfonates can be recovered in dry particulate free-flowing form by drum drying or, preferably, by spray-drying the solution~
The olefin sulfonates obtained are distin~uished by a light color and low sultone content. This sultone content is on average lower by the factor 100 (i.e., it is about 1%) of the sultone content of olefin sulfonates which have been hydrolyzed and bleached according to known methods. ~
The sultone content of the product can be determined -as follows: ;
10 ~rams of olefin sulfonate are dissolved in 100 ml ph/
.
~58138 .. ~ .
of a 1:1 water/ethanol mixture and are extracted with n-hexane.
The hexane fraction is removed and the hexane is allowed to evaporate. The residue is dissolved in chloroform and the resulting solution is poured into a chromatographic column charged with a weighed quantity of silica gel and the eluate is evaporated until the residue is dry.
The sultone contained in the residue may be deter-mined quantitatively by saponifying the sultone completely and performing a two-phase titration of the sulfonates thereby formed with hyamine solution (a quaternary ammonium cationic surfactant; see U.S. Patent No. 2,115,250) against a mixed indicator.
A quick qualitative determination is possible by thin-layer chromatography on silica gel and dyeing with 4~(4-nitrobenzyl)-pyridine.
The invention is further described by the examples which follow. These examples are best embodiments of the ..
invention and are not to be construea as limitative thereof.
EXAMPLES 1_TO 3 A linear C14-C18 olefin of which 80~ was of C16 chain length and wherein the double bonds were terminal was used as the starting material. It was continuously sulEonated in a thin-layer reactor with 1.1 mol of sulfur trioxide, which was present in 3% by volume dilution with air at a temperature of 32C. The extent of sulfonation (determined by saponification) was 95,7%.
Samples of this crude sulfonation mixture were hydro-lyzed and bleached under various conditions, as shown in the following table. Hydrolysis and bleaching were effected after the addition of 1.2 times the molar quantity of sodium hydroxide as a 30% aqueous solution. NaOCl was added as ph/
~,51~388 ~
bleach in the form of an aqueous solution containing 13~ active chlorine by weight. The bleaching was for 25 minutes at 60C~
(Hydrolysis and bleaching in at acid pH values were Qmitted since this procedure produces products which are distinctly darker in color and are, therefore, less useful). The pH
value of the solution was 14 (at 20C) during bleaching and ;~
also after the conclusion of hydrolysis. ,-~
The sultone content of the resulting solutions was determined quantitatively by the method described above. The color values of the solutions were determined in a 4" tube by use of the Lovibond tintometer after dilution of the solutions to a sulfonic content of 5% by weight.
The comparative tests are designated by letters.
The examples which illustrate the present invention are desig~
nated by numbers. Test series A utilizes unbleached sulfonates.
Test series B utilizes sulfonates bleached after hydrolysis.
Test series C utilizes sulfonates bleached prior to hydrolysis, and test series D utilized sulfonates simultaneously hydrolyzed and bleached. One solution was treated for 3 hours at 100C
and the other was treated for 10 minutes at 180c.
ph/
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.
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~1 ~1 5-1 ,_ r-lrl a) o~o ~: ~d ~ 1 a) .~ ~-1 al o _o ~ N ~J UJ O ~ ~) N -IJ O
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a) ~ a) ~ ~ ~ 0~o ,~ ~ :
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a~ V(d ~) Sl ~ a~ ) ~ ~ ~~ a) ~ o a) o ~ ~ ~ ~ al o .,:
(J)rl ~r-~-l (d ITJ r-l t~ ~1 rtr-~ ~-rl ~r-l Id ..
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:. '" ~, .
The olefin sulfonate solutions produced by the pro-cess of the present invention are distinguished by a sultone content of a maximum of 50 p.p.m. and by Lovibond color values of less than 3 for yellow, less than 0.4 for red, and 0 for blue. Solutions produced by other processes are unacceptably dark in color or have too high z sultone content or have both disadvantages.
The results show that the above process is capable ~
of rapidly decreasing the sultone content of the solution by -more than 98% with production of a very light colored solution.
The procedure of Example 3 is repeated except that the sodium hypochlorite solution added is replaced by aqueous hydrogen peroxide solution of equivalent bleaching strength.
The results are substantially the same.
The preceding specific embodiments are illustrative of the practice of the invention. It is to be understood, however, that other expedients known to those skilled in the art, or disclosed herein, may be employed without departing from the spirit of the invention or the scope of the appended claims ph/~r.
Claims (14)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for the production of alkali metal C8-22 .alpha.-olefin sulfonates of light color and of low sultone content comprising:
(a) reacting a C8-22 .alpha.-olefin with 1.0 to 1.5 mols of gaseous sulfur trioxide diluted with an inert gas to a concentration of 0.5% to 20% by volume thereby forming a crude sulfonation product mixture containing a C8-22 olefin sulfonic acid, with a content of sultones, (b) bleaching said crude sulfonation product mix-ture at 30°C to 80°C for 10 to 60 minutes with an aqueous alkaline bleaching solution at a pH of at least 8, (c) heating said diluted bleached sulfonation pro-duct mixture containing excess alkali to a temperature of from 140°C to 170°C for a time sufficient until the sultone content of the sulfonation product mixture is less than 100 ppm, and (d) recovering said alkali metal C8-22 .alpha.-olefin sulfonates of light color and of low sultone content.
(a) reacting a C8-22 .alpha.-olefin with 1.0 to 1.5 mols of gaseous sulfur trioxide diluted with an inert gas to a concentration of 0.5% to 20% by volume thereby forming a crude sulfonation product mixture containing a C8-22 olefin sulfonic acid, with a content of sultones, (b) bleaching said crude sulfonation product mix-ture at 30°C to 80°C for 10 to 60 minutes with an aqueous alkaline bleaching solution at a pH of at least 8, (c) heating said diluted bleached sulfonation pro-duct mixture containing excess alkali to a temperature of from 140°C to 170°C for a time sufficient until the sultone content of the sulfonation product mixture is less than 100 ppm, and (d) recovering said alkali metal C8-22 .alpha.-olefin sulfonates of light color and of low sultone content.
2. A process according to Claim 1 wherein the pH in the bleaching step is in the range of 10 to 14.
3. A process according to Claim 1 wherein said inorganic bleaching agent is sodium hypochlorite.
4. A process according to Claim 1 wherein said inorganic bleaching agent is hydrogen peroxide.
5. A process according to Claim 1 wherein the weight of said bleach is equivalent to 1% to 3% by weight, based on the olefin sulfonate content of NaOCl.
6. A process according to Claim 1 wherein said crude sulfonation product mixture is diluted to a 20% to 60% by weight solution.
7. A process according to Claim 1 wherein in Step (b) the temperature during said bleaching is 50°C to 60°C.
8. A process according to Claim 1 wherein in Step (c) the temperature at which solution is heated is 150°C to 165°C.
9. A process according to Claim 1 wherein the pH
after hydrolysis is complete in Step (c) is at least 9.
after hydrolysis is complete in Step (c) is at least 9.
10. A process according to Claim 1 wherein the pH after hydrolysis is complete in Step (c) is in the range of 11 to 14.
11. A process according to Claim 1 wherein said heating Step (c) is continued until the sultone content is less than 50 p.p.m.
12. A process according to Claim 1 whereas the amount of said sulfur trioxide is 1.05 to 1.15 mol per mol of said .alpha.-olefin.
13. A process according to Claim 1 wherein the bleaching is effected by the action of an inorganic bleaching agent, equivalent to 0.5% to 5% by weight, based on the ole-fin sulfonate content, of NaOCl.
14. A process according to Claim 13 wherein the bleaching agent is selected from the group consisting of active oxygen bleaching agents and active chlorine bleaching agents.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT815875A AT337143B (en) | 1975-10-27 | 1975-10-27 | PROCESS FOR THE PREPARATION OF LIGHT COLORED LOW SULTON OLEFINSULPHONATES |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1065888A true CA1065888A (en) | 1979-11-06 |
Family
ID=3603086
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA264,088A Expired CA1065888A (en) | 1975-10-27 | 1976-10-25 | Method for the production of bleached, low-sultone olefin sulfonates |
Country Status (12)
| Country | Link |
|---|---|
| JP (1) | JPS5253818A (en) |
| AT (1) | AT337143B (en) |
| BE (1) | BE847619A (en) |
| BR (1) | BR7607169A (en) |
| CA (1) | CA1065888A (en) |
| DE (1) | DE2647523A1 (en) |
| FR (1) | FR2329652A1 (en) |
| GB (1) | GB1540152A (en) |
| IT (1) | IT1068924B (en) |
| MX (1) | MX3872E (en) |
| NL (1) | NL7611038A (en) |
| SE (1) | SE7611108L (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11389384B2 (en) * | 2017-05-29 | 2022-07-19 | Basf Se | Method for producing a light-coloured disalt |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2146323B (en) * | 1983-09-09 | 1987-09-09 | Godrej Soaps Ltd | Production of sodium alpha olefin sulphonate and products containing it |
| CA2702587A1 (en) * | 2007-10-26 | 2009-04-30 | Chevron Oronite Company Llc | Isomerized alpha olefin sulfonate and method of making the same |
-
1975
- 1975-10-27 AT AT815875A patent/AT337143B/en not_active IP Right Cessation
-
1976
- 1976-10-06 NL NL7611038A patent/NL7611038A/en not_active Application Discontinuation
- 1976-10-06 SE SE7611108A patent/SE7611108L/en not_active Application Discontinuation
- 1976-10-20 MX MX764989U patent/MX3872E/en unknown
- 1976-10-21 DE DE19762647523 patent/DE2647523A1/en not_active Withdrawn
- 1976-10-25 CA CA264,088A patent/CA1065888A/en not_active Expired
- 1976-10-25 BE BE171771A patent/BE847619A/en unknown
- 1976-10-26 BR BR7607169A patent/BR7607169A/en unknown
- 1976-10-26 GB GB44351/76A patent/GB1540152A/en not_active Expired
- 1976-10-26 IT IT28682/76A patent/IT1068924B/en active
- 1976-10-27 FR FR7632411A patent/FR2329652A1/en active Granted
- 1976-10-27 JP JP51129291A patent/JPS5253818A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11389384B2 (en) * | 2017-05-29 | 2022-07-19 | Basf Se | Method for producing a light-coloured disalt |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5253818A (en) | 1977-04-30 |
| FR2329652A1 (en) | 1977-05-27 |
| AT337143B (en) | 1977-06-10 |
| NL7611038A (en) | 1977-04-29 |
| BR7607169A (en) | 1977-09-13 |
| ATA815875A (en) | 1976-10-15 |
| GB1540152A (en) | 1979-02-07 |
| MX3872E (en) | 1981-08-26 |
| DE2647523A1 (en) | 1977-04-28 |
| IT1068924B (en) | 1985-03-21 |
| FR2329652B1 (en) | 1979-08-10 |
| SE7611108L (en) | 1977-04-28 |
| BE847619A (en) | 1977-04-25 |
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