Organic compounds -- part of the class 532-570 series – Organic compounds – Sulfonic acids or salts thereof
Patent
1999-10-22
2000-09-26
Gerstl, Robert
Organic compounds -- part of the class 532-570 series
Organic compounds
Sulfonic acids or salts thereof
562828, 562829, C07C30316
Patent
active
06124497&
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention relates to the manufacture of alkane sulfonic acids and sulfonyl chlorides by oxidation of the corresponding alkanethiol or dialkyl disulfide. More specifically, it relates to the oxidation of such compounds, in the presence of nitric acid or a nitrogen oxide and Br.sub.2 or HBr, to form the corresponding sulfonic acids or sulfonyl chlorides.
BACKGROUND OF THE INVENTION
Alkylsulfonic acids (or alkane sulfonic acids) and alkyl sulfonyl chlorides are well known large scale commercial products useful as surfactants and as chemical intermediates among other applications. Thus it is desirable to prepare them by a highly efficient process which results in no or a minimum of by-products and which is environmentally sound. The process of this invention provides such a synthesis.
DISCUSSION OF THE PRIOR ART
Numerous methods have been used previously to prepare alkyl sulfonic acids from alkylthiols and disulfides. However, these methods tend to be uneconomic, or to result in the production of unwanted side products. The most commonly used method for the manufacture of alkane sulfonic acids involves oxidation of the corresponding alkanethiol or dialkyl disulfide by chlorine in concentrated hydrochloric acid media, as disclosed, for example, in
U.S. Pat. No. 3,630,004 to Adair, et al. and U.S. Pat. No. 4,280,966 to Hubenett. This method suffers from the disadvantage that a significant amount of side products is formed. The side product results from the side chain chlorination of the alkyl group, particularly in the case of higher alkane sulfonic acids. A large amount of hydrochloric acid is also formed as a by-product of the oxidation reaction which presents a disposal problem. In addition, side products result from the side chain chlorination of the alkyl chain of the alkanethiol or disulfide and this is a concern, particularly in the case of higher alkane sulfonic acids.
Oxidation of aliphatic thiols and disulfides to the corresponding sulfonic acid by heating in an excess of is dimethyl sulfoxide, with a catalytic amount of bromine, iodine or hydrogen iodide as a secondary catalyst, is disclosed in U.S. Pat. No. 3,948,922 to Lowe. Oxidation of the sulfide-sulfur bond-containing compounds by lower dialkyl sulfoxides, promoted by bromide ion, is described in U.S. Pat. No. 3,428,671 to Toland. Oxidation of thiols to disulfides by their reaction with a lower alkyl sulfoxide in the presence of a catalyst consisting of chlorine or hydrogen chloride as the primary catalyst and iodine or hydrogen iodide as a secondary catalyst is disclosed in U.S. Pat. No. 3,954,800 to Lowe. In these processes using dimethyl sulfoxide as the oxidizing agent, this agent is consumed in stoichiometric amounts. In view of the high cost of dimethyl sulfoxide, such a process is uneconomic. Further, because of the intense odor of the dimethyl sulfide formed, the process may cause difficult environmental problems.
More recently, European Patent Application Publication No. 4,424,616 A2 discloses that alkanethiol and dialkyl sulfides may be converted to alkyl sulfonic acids with oxygen and a catalytic amount of a lower dialkyl sulfoxide using water and a hydrogen halide (e.g., HI, HBr and their mixtures). Yields for the reaction, however, are quite low.
Proell, et al., U.S. Pat. No. 2,433,395, disclose that alkyl mercaptans and alkyl disulfides may be converted to alkyl sulfonic acids in an aqueous system using oxygen and a nitrogen oxide. However, the oxidation is incomplete and the process is not commercially viable.
U.S. Pat. No. 2,697,722 to Johnson, et al. discloses the aqueous oxidation of alkyl disulfides with oxygen, but the process does not employ the co-catalyst of this invention.
The conversion of alkane thiols and disulfides to alkyl sulfonyl chlorides by use of chlorine and HCl is also known. However, this process also suffers from the same disadvantage of producing large amounts of hydrochloric acid as co-product. The side chain chlorination of the alkyl chain is also a concern with this reac
REFERENCES:
patent: 3993692 (1976-11-01), Giolito
Gerstl Robert
Innochem Inc.
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