STUDIES ON REACTIONS RELATING TO CARBOHYDRATES AND POLYSACCHARIDES: XLVIII. ETHYLENE OXIDE AND RELATED COMPOUNDS: SYNTHESIS OF THE POLYETHYLENE GLYCOLS

Abstract

Four new methods are outlined for the synthesis of polyethylene glycols.Ethylene glycol heated to 190 °C. with 0.3% of its weight of iodine as a catalyst loses water to form diethylene- and other polyethylene glycols. The reaction is progressive and reversible. The yield of polyethylene glycols is about 25%.The other three methods consist of modifications of a general method in which one mole of the dichloro derivative of a polyethylene glycol (the chlorine atoms forming the terminal groups) reacts with two moles of the monosodium salt of a polyethylene glycol. For this reaction the monosodium salt is obtained by one of the following methods: (a) direct solution of metallic sodium in the glycol; (b) reaction of metallic sodium with a methanol solution of the glycol in presence of anhydrous ether; (c) evaporation of a solution of the glycol and concentrated sodium hydroxide under diminished pressure.Proof of the structure of these compounds is afforded by their analyses, their refractive indices, and their conversion into the corresponding dichloride by the action of thionyl chloride in pyridine solution.