Claims
- 1. A process for producing a hydroxy sulfonic acid by the oxidation of a mercaptan selected from the class consisting of hydroxy mercaptans of the formula: ##STR10## wherein R.sub.1 and R.sub.2 are independently selected from hydrogen, halogen, hydroxy and unsubstituted or substituted cyclic, acyclic, alicyclic, straight or branched chain organic groups, R.sub.3 and R.sub.4 are independently selected from hydrogen and organic groups as defined for R.sub.1 and R.sub.2, and Y is a covalent bond or an organic group as defined for R.sub.1 and R.sub.2, said process comprising the steps of:
- (a) adding a reactor an aqueous hydrogen peroxide solution having a concentration below about 40% by weight in an amount equal to between about 20% and about 40% of the stoichiometric ratio based on the total quantity of mercaptan being oxidized, said solution being heated to a temperature below about 75.degree. C.;
- (b) adding said mercaptan to said reactor; and
- (c) simultaneously adding an additional stream of aqueous hydrogen peroxide into the reactor, the amount of hydrogen peroxide so added, when combined with the hydrogen peroxide previously introduced into the reactor, being an excess of no more than about 10% greater than the stoichiometric amount required to selectively oxidize the mercaptan to a sulfonic acid, the relative rates of said additions being adjusted so that the addition of the hydrogen peroxide is complete before the final addition of the mercaptan is made, with the temperature of the reacting medium being maintained below about 75.degree. C.
- 2. The process of claim 1 wherein said mercaptan is selected from the group consisting of 2 -hydroxyethyl mercaptan, 1-mercapto-2-hydroxypropane, 2-mercapto-1-hydroxypropane, 1-mercapto-2-hydroxybutane, 2-mercapto-1-hydroxybutane, 2-mercapto-3-hydroxybutane, 2-mercapto-2-methyl-1-hydroxypropane, 1-mercapto-2-methyl-2-hydropropane, 1-mercapto-2-cyclohexyl-2-hydroxyethane, 2-mercapto-1-hydroxy-3-bromopropane, 1-mercapto-2-hydroxy-3-bromopropane, 1-mercapto-1-chloro-2-hydroxypropane, 2-mercapto-1-hydroxypropane, 2-mercapto-1-hydroxypropane, 2-mercapto-1-hydroxy-3-chloropropane, 1-mercapto-2-hydroxy-3-chloropropane, 2-mercapto-3-hydroxy-1-bromotuane, 2-mercapto-3-hydroxy-1-chlorobutane, 2-mercapto-1-hydroxy-3-bromobutane, 1-mercapto-2-hydroxy-3-bromobutane, 2-mercapto-1-hydroxy-3-chlorobutane, 1-mercapto-2-hydroxy-3-chlorobutane, 1-mercapto-2-methyl-2-hydroxy-3-chloropropane, 2-mercapto-3-hydroxy-1-chloropropane, 1-mercapto-2-hydroxy-2-(chloromethyl)-3-chloropropane, 2-mercapto-3-hydroxy-2-(chloromethyl)-3-chloropropane, 2-mercapto-1-methoxy-3-hydroxypropane, 1-mercapto-3-methoxy-2-hydroxypropane, 1-mercapto-2-hydroxycyclohexane, 1-mercapto-2-phenyl-2-hydroxyethane, 1-mercapto-1-phenyl-2-hydroxyethane, 1-mercapto-2-methyl-2-bromo-3-phenyl-3-hydroxypropane, 1-mercapto-4-hydroxybutane, and mixtures thereof.
- 3. A process for production of hydroxy sulfonic acids by the oxidation of a mercaptan selected from the class consisting of hydroxy mercaptans of the formula: ##STR11## wherein R.sub.1 and R.sub.2 are individually selected from hydrogen, and unsubstituted alkyl, cycloalkyl or aryl groups of 1 to 50 carbon atoms, halogen or hydroxyl substituted alkyl, cycloalkyl or aryl groups having 1 to about 50 carbon atoms, (halogen or hydroxyl substituted or unsubstituted) alkyl substituted cycloalkyl or aryl groups having 1 to about 50 carbon atoms, and saturated polyhydrocarbyloxy groups, and X is an integer in the range of from 0 to 4, said process comprising the steps of:
- (a) adding to a reactor an amount of an aqueous hydrogen peroxide solution having a concentration below about 40% by weight in an amount equal to between about 20% and about 40% of the stoichiometric ratio based on the total quantity of mercaptan being oxidized, said solution being heated to a temperature below about 75.degree. C.;
- (b) adding an amount of said mercaptan; and
- (c) simultaneously adding an additional stream of aqueous hydrogen peroxide into the reactor, the amount of peroxide so added, when combined with the hydrogen peroxide previously introduced into the reactor, being an excess of hydrogen peroxide equal to no more than about 10% above the stoichiometric amount necessary to selectively oxidize the mercaptan to a sulfonic acid, the relative rates of said additions being adjusted so that the addition of the peroxide is complete before the final addition of the mercaptan is made, with the temperature of the reacting medium being maintained below about 75.degree. C.
- 4. The process of claim 3 wherein R.sub.1 and R.sub.2 each has between 1 and about 30 carbon atoms.
- 5. The process of claim 3 wherein the hydrogen peroxide concentration is between 25% and 35% by weight.
- 6. The process of claim 3 wherein the total amount of hydrogen peroxide provided is no more than 5% above stoichiometric.
- 7. The process of claim 6 wherein the total amount of hydrogen peroxide provided is no more than 1% above stoichiometric.
- 8. The process of claim 3 wherein said oxidation of said mercaptan is initiated in the absence of added acid.
- 9. The process of claim 3 further comprising the addition of between 0.5 ppm and 4 ppm of a mild reducing agent.
- 10. The process of claim 9 wherein the concentration of said reducing agent is between 1 ppm and 3 ppm.
- 11. The process of claim 1 wherein said reducing agent comprises FeSO.sub.4 ]H.sub.2 O.
- 12. The process of claim 3 further comprising the step of concentrating the hydroxy sulfonic acid solution.
- 13. The process of claim 12 wherein said concentration step comprises evaporating a sufficient amount of the water of dilution of the hydrogen peroxide solution and the water formed by the reduction of the hydrogen peroxide to create an essentially saturated solution of hydroxy sulfonic acid.
- 14. The process of claim 3 wherein said mercaptan is 2-hydroxy ethyl mercaptan.
- 15. The process of calim 3 wherein all R groups, if organic, contain no more than about 15 carbon atoms.
- 16. The process of calim 3 wherein all R groups, if organic, contain no more than about 10 carbon atoms.
- 17. The process of calim 3 wherein all R groups, if organic, contain no more than about 4 carbon atoms.
- 18. A process for the production of isethionic acid from 2-hydroxyethyl mercaptan comprising the steps of:
- (a) adding to an enclosed reactor an amount of a 25% to 35% by weight aqueous solution of hydrogen peroxide, said amount being equal to between about 25% and about 35% of the stoichiometric amount to selectively oxidize the hydrosulfide group of the total amount of said mercaptan to a sulfonic acid group;
- (b) heating said solution under a vacuum sufficient to lower the boiling point of water to about 75.degree. C. or less; and
- (c) adding to said reactor an amount of said mercaptan while simultaneously adding to the reactor, an additional stream of aqueous hydrogen peroxide at a rate such that the quantity of peroxide within the reactor is always at a concentration greater than the stoichiometric amount for the amount of mercaptan therein, the total amount of peroxide added in steps (a) and (c) being an excess of no more than 5% greater than the stoichiometric amount required to selectively oxidize the total amount of sulfur in the mercaptan while leaving the hydroxyl group intact, the rates of such additions further being adjusted so that the temperature of the reactants is maintained below about 75.degree. C.
- 19. The process of claim 18 further comprising controllably evaporating at least a portion of the water of dilution of the hydrogen peroxide and the water generated by the oxidation of the thiol group of said mercaptan.
- 20. A process for the production of isethionic acid from 2-hydroxy ethyl mercaptan comprising the steps of:
- (a) adding to an enclosed reactor a mixture comprising an amount of a 30% to 35% aqueous solution of hydrogen peroxide equal to between about 25% to 30% of the stoichiometric amount to selectively oxidize the thiol group of said mercaptan to a sulfonic acid group and between 1 ppm and 3 ppm of a mild reducing agent;
- (b) heating the mixture in said reactor under a vacuum sufficient to lower the boiling point of water to below about 70.degree. C.; and then
- (c) adding an amount of said mercaptan while simultaneously adding an additional stream of aqueous hydrogen peroxide, the rates of such additions being adjusted such that the quantity of peroxide within the reactor is always at a concentration greater than the stoichiometric amount for the amount of mercaptan therein and the total amount of peroxide provided being an excess of no more than 1% greater than the stoichiometric amount required for the total amount of sulfur in the mercaptan added, the rates of such additions further being adjusted so that the temperature of the reactants is maintained between about 65.degree. C. and 75.degree. C.
- 21. The process of claim 20 wherein said mild reducing agent comprises FeSO.sub.4 .multidot.7H.sub.2 O.
- 22. The process of claim 20 further comprising controllably evaporating at least a portion of the water of dilution of the hydrogen peroxide and the water generated by the oxidation of the thiol group.
Parent Case Info
This application is a division, of application Ser. No. 101,146, filed Sept. 25, 1987 now U.S. Pat. No. 4,910,330.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
4239696 |
Schreyer et al. |
Dec 1980 |
|
4910330 |
McGee et al. |
Mar 1990 |
|
Non-Patent Literature Citations (2)
Entry |
Chem Abst Sjoberg (1939), p. 2106(8). |
Gilbert Sulfonation & Related Reactors (1965), p. 220. |
Divisions (1)
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Number |
Date |
Country |
Parent |
101146 |
Sep 1987 |
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