Process for the production of alkali-metal peroxides

摘要

1,128,953. Alkali metal peroxides; hydrogen peroxide. INSTITUT FRANCAIS DU PETROLE DES CARBURANTS ET LUBRIFIANTS. 7 Jan., 1966 [9 Jan., 1965; 20 Aug., 1965], No. 933/66. Heading C1A. Alkali metal peroxides are prepared by contacting a solution of a non-enolysable ketone in a liquid hydrocarbon with an alkali metal amalgam and reacting molecular oxygen with the resulting solution to form alkali metal peroxide which separates from the solution in solid form. The term alkali metal peroxide means the superoxide, e.g. NaO 2 or KO 2 as well as the true peroxide Na 2 O 2 or K 2 O 2 , the two compounds generally being obtained in a mixed product. The liquid phase separated from the peroxide may be recycled for contact with the amalgam or the dissolution of the alkali metal from the amalgam and the oxidation of the ketyl formed may take place in a single reaction chamber provided contact between the oxidizing gas and the amalgam is prevented. Thus the amalgam may be placed in the reaction below the ketone solution and molecular oxygen may be introduced at a higher level than the amalgam/ketone solution interface. The ketone may be of the formula R-CO-R1 where at least one of R and R1 is a monovalent homocyclic or heterocyclic aromatic hydrocarbon radical or a radical of the formula where R 1 and R 2 may be the same or different and may be hydrogen atoms or monovalent hydrocarbon radicals and R 3 is a monovalent hydrocarbon radical, one of R and R1 may be a monovalent aliphatic or cycloaliphatic hydrocarbon radical totally substituted in theα- position relative to the CO group. Preferred ketones are benzophenone and fluorenone. The hydrocarbon solvent may be an aromatic hydrocarbon, preferably benzene and the ketone may be used in a concentration of 0À05-1 mol./litre of solution. The reaction temperature may be between- 10‹ and + 70‹ C. and a Lewis base, preferably hexamethylphosphoramide, may be added to the ketone to improve the solubility of the ketyl. The concentration of Lewis base may be 0À01 to 1 mol./litre of ketone solution. The alkali metal peroxide formed may be converted after separation or in the form of a suspension in the organic solution into other peroxide compounds. It may be treated with aqueous acetic acid, hydrochloric acid, sulphuric acid or glacial acetic acid to form hydrogen peroxide. Alkali metal perborates may be formed by treating it with alkali metal borates, possibly in the presence of carbon dioxide and alkali metal percarbonates may be formed by the action of carbon dioxide on the suspension of the peroxide in the ketone.