Title of Invention

"AN ELECTROCHEMICAL PROCESS FOR THE PREPARATION OF COBALTIC METHANE SULPHONATE"

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.



Documents:

402-del-2002-abstract.pdf

402-DEL-2002-Claims-(14-07-2008).pdf

402-del-2002-claims.pdf

402-DEL-2002-Correspondence-Others-(14-07-2008).pdf

402-del-2002-correspondence-others.pdf

402-del-2002-correspondence-po.pdf

402-del-2002-description (complete)-14-07-2008.pdf

402-del-2002-description (complete).pdf

402-del-2002-form-1.pdf

402-del-2002-form-18.pdf

402-DEL-2002-Form-2-(14-07-2008).pdf

402-del-2002-form-2.pdf

402-DEL-2002-Form-3-(14-07-2008).pdf

402-del-2002-form-3.pdf


Patent Number 222075
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.
Inventors:
# Inventor's Name Inventor's Address
1 KRISHAMURTHY JAYARAMAN CENTRAL ELECTROCHEMICAL RESEARCH INSTITUTE, KARAIKUDI, TAMIL NADU, INDIA.
2 VELLASAMY DEVADOSS CENTRAL ELECTROCHEMICAL RESEARCH INSTITUTE, KARAIKUDI, TAMIL NADU, INDIA.
3 CHIYA AHMED BASHA CENTRAL ELECTROCHEMICAL RESEARCH INSTITUTE, KARAIKUDI, TAMIL NADU, INDIA.
PCT International Classification Number C07F 9/553
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA