GB490387A - Improvements in production of alcoholates and anhydrous alcohols - Google Patents

Abstract

Anhydrous alcohols and/or alcoholates having not more than four carbon atoms are obtained by treating the aqueous or anhydrous alcohols in the liquid phase with an alkali metal amalgam in the presence of an electrically conducting non-amalgamating electrode. Suitable electrodes may be made of carbon or alloys of iron and chromium, with or without nickel. When an aqueous alcohol is employed, enough alkali amalgam is used to react with all the water, and the anhydrous alcohol is then distilled off and may be treated with more amalgam to produce the alcoholate. A part only of the aqueous alcohol may be treated with excess of amalgam so as to produce alkali and alcoholate, which is then added to the rest of the aqueous alcohol so as to react the contained water with the alcoholate to yield anhydrous alcohol. Alcohols containing not less than four carbon atoms may be dehydrated by first reacting a lower alcohol with amalgam as described above to produce alcoholate, and then adding the product to the aqueous higher alcohol in amount equivalent to the water present, after which the lower alcohol is distilled off first and the anhydrous higher alcohol subsequently; thus methyl alcohol may be reacted with sodium amalgam in the presence of a carbon or cast iron electrode, and the alcoholate product then added to aqueous tertiary amyl or butyl alcohol. The invention is applied to the dehydration of alcohols of boiling-points not above 125 DEG C. In another example, aqueous ethyl alcohol is treated with sodium amalgam in the presence of a carbon electrode, and the anhydrous alcohol separated by distillation is treated with more amalgam in the presence of a carbon electrode to produce alcoholate. The amalgam preferably contains less than 1 per cent of alkali metal. The electrode may be in the form of a grid in contact with the amalgam and with the alcohol layer. A number of specific iron-chromium and iron-chromium-nickel alloys and also alloys of specific proportions of cobalt, chromium and tungsten; nickel, iron, molybdenum and manganese; and nickel, molybdenum, chromium, iron and tungsten are mentioned as suitable for the electrode. The Specification as open to inspection under Sect. 91 includes the production of alcoholates of alcohols containing more than four carbon atoms by reacting the higher alcohol with the lower alcoholate. The higher alcohol may be primary, secondary or tertiary, saturated or unsaturated or may be a cyclic alcohol such as cyclohexanol or benzyl alcohol. Examples describe the reaction of secondary amyl alcohol, cyclohexanol, and butyl alcohol respectively with sodium alcoholates prepared from methyl or ethyl alcohol and sodium amalgam in the presence of a graphite, iron or alloy electrode. Xanthates may be produced by reacting carbon disulphide with alkali alcoholates in solution in the corresponding alcohols, and examples describe the production of sodium ethyl, sodium tertiary butyl, sodium secondary amyl, and sodium butyl xanthates in this manner. Alkali alcohol carbonates are produced by treating with dry carbon dioxide a dry alcoholic solution of alkali alcoholate, the carbonate being precipitated. An example describes the production of sodium methyl carbonate in this manner. This subject-matter does not appear in the Specification as accepted.ALSO:Several specific iron-chromium and iron-chromium-nickel alloys, and also alloys of specific proportions of cobalt, chromium, and tungsten; nickel, iron, molybdenum, and manganese; and nickel, molybdenum, chromium, iron, and tungsten, are mentioned as suitable for certain electrodes employed in the production of alkali alcoholates.