GB1188557A - An Electrolytic Process for the Manufacture of Diacetone 2-Keto-Gulonic acid - Google Patents

Abstract

1,188,557. Electrolytic preparation of diacetone 2-keto-gulonic acid. F. HOFFMANN-LA ROCHE & CO. A.G. Aug.22, 1967 [Aug. 24, 1966], No.38680/67. Heading C7B. [Also in Division C2] Diacetone 2-keto-gulonic acid is produced by passing a current through an aqueous alkaline solution of pH greater than 9 containing diacetone sorbose using a nickel oxide anode in which the nickel has an average valency of from 2À7 to 4. The cathode may be of stainless steel, "Monel" (R.T.M. ), Pt or Pd and the nickel oxide is preferably supported on a conductive material such as stainless steel, "Monel", sintered Ni, Ni plated iron, graphite or carbon. The nickel oxide coating may be formed before carrying out the process by impregnating a porous sintered Ni body with a nickel salt and then subjecting the body to anodic treatment or the support material may be connected as anode in a first stage of the process in the presence of nickel hydroxide and/or oxide or a nickel salt such as nitrate, sulphate acetate or formate, although the nickel compound may be omitted if the support is of sintered Ni. The organic acid is produced in a bath at 25‹ to 85‹ C. which is agitated mechanically or by pumped circulation. The cell may comprise a litre flash with a cylindrical stainless steel grid anode support and a spiral nickel wire cathode or may comprise a vertical stack of three stainless steel screen cathodes and two sintered Ni anode supports with mechanical agitators. Alternatively the cell may comprise nickel-plated cast iron or stainless steel electrodes separated by a synthetic fabric diaphragm with pump circulation of electrolyte through the anolyte and catholyte chamber.