GB573087A - Process for the preparation of 2-methyl-4-keto-1,3-dioxolane - Google Patents

Abstract

2 - Methyl - 4 - keto - 1,3 - dioxolane is prepared by reacting acetylene at 0-50 DEG C., with hydroxyacetic acid in an anhydrous medium in the presence of a catalyst containing mercuric sulphate and a lower fatty acid anhydride of not more than 8 carbon atoms. The anhydrous medium may be a dialkyl ketone containing not more than 5 carbon atoms in the molecule such as acetone, methyl ethyl ketone or methylisopropyl ketone or a lower aliphatic alcohol such as methanol. The catalyst can be prepared by mixing mercuric sulphate with sulphuric acid and acetic anhydride, or by mixing mercuric sulphate acetate or phosphate with mercuric oxide and adding more than one mol. of sulphuric acid and acetic anhydride per mol. of mercuric oxide. Other fatty acid anhydrides which may be used are propionic and butyric. In the examples: (1) a mixture of hydroxyacetic acid, dry acetone, mercuric sulphate, mercuric oxide and a dehydrating agent of anhydrous sodium sulphate are placed in a pressure bomb and a cooled mixture of sulphuric acid and acetic anhydride added. Acetylene is introduced under pressure and the apparatus agitated. 2 - Methyl - 4 - keto - 1,3 - dioxolane is obtained from the reaction mixture by adding sodium acetate and water, extracting with ether and fractionally distilling at atmospheric pressure and under vacuum; (2) a mixture is prepared as in example (1) and acetylene passed through the mixture for some hours. 2 - Methyl-4-keto-1,3-dioxolane is obtained from the reaction mixture in the same manner as in example (1). 2 - Methyl - 4 - keto - 1,3 - dioxolane may be used as a solvent and plasticizer and in the modification of hydroxyl containing polymers, such as cellulose and polyvinyl alcohol. It can be polymerized by treatment with sulphuric acid, hydrochloric acid and boron trifluoride.