Title of Invention | "AN ELECTROCHEMICAL PROCESS FOR THE PREPARATION OF COBALTIC METHANE SULPHONATE" |
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Abstract | The present invention relates to an improved process for the preparation of cobaltic methane sulphonate particularly relates to the development of an electrochemical process for the oxidation of cobaltous [Co2+] to cobaltic [Co3+] in methane sulphonic acid medium |
Full Text | The present invention relates to an improved process for the preparation of cobaltic methane sulphonate.particularly relates to the development of an electrochemical process for the oxidation of cobaltous [Co2+] to cobaltic [Co3+] in methane sulphonic acid medium,. Cobaltic compounds find wide application as oxidizing agents in chemical industry and cobaltic methane sulphonate will be useful in selective oxidations of substituted toluenes, aromatic hydrocarbons etc. Cobaltic salts can be prepared by oxidation of cobaltous salts with strong oxidizing agents such as fluorine [H.Fichter and H.Wolfmann, Helv. Chim. Acta,12 (1929) 208], ozone [E.Brumer, Helv. Chim. Acta, 12 (1929) 208], sodium persulphate [S.Kitashima, Bull. Inst. Phys. Chem. Research (Tokyo), 70 (1928) 1035] and also by electrolytic oxidation of Co2* in acid medium. Electrochemical oxidation of cobaltous to cobaltic in sulphuric acid medium [S.Swann and T.S.Xanthakos, J. Amer. Chem. Soc., 53 (1939) 400, Ch. Comninellis, E.Plattner, Ph. Javet, J. Applied Electrochem., 9 (1979) 595-601] and acetic acid medium [D.C.Trivedi, K.S.udupa and H.V.K.Udupa, Proc. Inst. of Chemist, Part IV, 50 (1978) 95, D.C.Trivedi and S.K.Dhawan, B. Electrochem., 6 (1990) 95, S.S.Lande, C.D.Falk and J.K.Kochi, J. Inorg. Nucl. Chem., 33 (1971) 4101, D.C.Trivedi and S.K.Dhawan, J. Applied Electrochem., 21 (1991) 504] has been reported. These processes have the following drawbacks: (1) Cobaltic salts are highly unstable and rapidly get reduced to cobaltous in aqueous solutions. (2) Low conversions and current efficiencies were reported for the electrolytic preparation of cobaltic in sulphuric and acetic acid medium. (3) High concentrations of cobaltic could not be generated by electrolytic methods reported in literature. The mam objective of the present invention is to provide an electrochemical process for the preparation of cobaltic methane sulphonate, Another objective of the present invention is to develop an electrochemical method for the oxidation of cobaltous to cobaltic in methane sulphonic acid (MSA) medium. Yet another objective of the invention is to prepare cobaltic in the stable form in MSA medium. Yet another objective of the invention is to prepare cobaltic in high concentrations in MSA medium for use in organic synthesis. Accordingly the present invention provides an electrochemical method for the preparation of cobaltic methane sulphonate which comprises; electrolysing cobaltous methane sulphonate of concentration ranging between 0.13 to 1.25M in aqueous methane sulphonic acid medium using a divided type electrolyser provided with n CM.•h.ms.'.e membrane as the cell divider, platinum/lead-di-oxide/ titanium substrate insoluble (1'SIA) anode stainless steJ cathodes at a current density ranging between 0.5 to 5.0 A/dm2, at a temperatures ranging between 5°C to 50°C and electrolyte concentrations of 1.0 to 10.0M methane sulphonic acid for a duration upto 185% of theoretical charge required for oxidation. In an another embodiment of the present invention, electrochemical oxidation of cobaltous to cobaltic in MSA medium is conducted at platinum/lead-di-oxide/TSIA anodes and stainless steel cathodes in a divided type of electrolyser provided with cation exchange membranes. The process consists of the electrochemical oxidation of cobaltous methane sulphonate (0.13 to 1.25M) dissolved in aqueous methane sulphonic acid (1.0 to 10.0M) in a divided type of electrochemical reactor provided with cationic membrane and the oxidation is conducted at platinum / lead dioxide / TSIA anodes and stainless steel cathodes. The electrolysis temperature is maintained between 5 and 50°C and the anode current density between 0.^ and 5.0 A/dm2. Electrolysis is conducted for a duration of upto 185% of the theoretical charge required for the oxidation. Cobaltic formed at the end of electrolysis is estimated potentiometrically and the concentration of cobaltic formed during electrolysis varies between 0.07 to 0.8M. Current efficiencies of 20-55% and conversions of 50-85% are achieved for the oxidation. Cobaltic obtained is highly stable and the concentration of Co3+ in solution decreases only by 5-10% of the initial value after a period of 30 days. Following examples are given by way of illustration and should not be construed to limit the scope of the invention. Electrochemical oxidation of cobaltous to cobaltic Experimental Conditions Cathode : Stainless steel Catholyte : Aqueous methane sulphonic acid Diaphragm : NAFION cationic membrane (Table Removed) We claim 1) An electrochemical process for the preparation of cobaltic methane sulphonate which comprises electrolyzing cobaltous methane sulphonate of concentration ranging between 0.13 to 1.25M in aqueous methane sulphonic acid medium using a divided type electrolyser provided with cation exchange membrane as the cell divider, platinum/ lead-di-oxide/ titanium substrate insoluble (TSIA) anode and stainless steel cathodes at a current density ranging between 0.5 to 5.0 A/dm2, at a temperatures ranging between 5°C to 50°C and electrolyte concentrations of 1.0 to 10.0M methane sulphonic acid for a duration upto 185% of theoretical charge required for oxidation. 2) A process as claimed in claim 1 wherein the cation exchange membrane used is nafion cationic membrane. 3) An electrochemical process for the preparation of cobaltic methane sulphonate as substantially herein described with reference to the example accompanying this specification. |
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402-DEL-2002-Claims-(14-07-2008).pdf
402-DEL-2002-Correspondence-Others-(14-07-2008).pdf
402-del-2002-correspondence-others.pdf
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402-del-2002-description (complete)-14-07-2008.pdf
402-del-2002-description (complete).pdf
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402-DEL-2002-Form-3-(14-07-2008).pdf
Patent Number | 222075 | ||||||||||||
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Indian Patent Application Number | 402/DEL/2002 | ||||||||||||
PG Journal Number | 32/2008 | ||||||||||||
Publication Date | 08-Aug-2008 | ||||||||||||
Grant Date | 17-Jul-2008 | ||||||||||||
Date of Filing | 28-Mar-2002 | ||||||||||||
Name of Patentee | COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH | ||||||||||||
Applicant Address | RAFI MARG, NEW DELHI-110 001, INDIA. | ||||||||||||
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PCT International Classification Number | C07F 9/553 | ||||||||||||
PCT International Application Number | N/A | ||||||||||||
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