Etherification with alkylene oxides

Extended studies on starch etherification with C2 to C5 aliphatic alkylene oxides in alkaline slurries have been performed 944,945 This reaction was subsequently re-examined for hydroxypropylation.946 No significant effects were observed as a result of using added hydrogen peroxide, benzoyl peroxide, azodiisobutyronitrile, or K2S2O8.945 In all instances, including those studied without such additives, led to water- and alcohol-soluble thermoplastic materials. Further improvements involved etherification in either acetone or butanone in the presence of aqueous NaOH. Ethylene oxide was introduced incrementally.947 Etherification of starch... 

Hydroxyalkyl substituents are characterized by weight percent or by the molar degree of substitution (MS), which is the average number of alkylene oxide reacted with each anhydroglucose unit. The MS includes also side chain formation due to further etherification of hydroxyl groups of the hydroxyalkyl substituent and may take on any value. 

Cellulose ethers, such hydroxyethyl cellulose or hydrox5rpropyl cellulose, are water soluble cellulose derivatives which may be produced by etherification of alkali cellulose with epoxides, e.g., ethylene oxide or propylene oxide (36). Cellulose is made alkaline in sodium hydroxide solution and subsequently reacted with the corresponding alkylene oxides. 

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