Starch Benzoate and Cinnamate

Starch benzoate may be prepared by treating dry starch in pyridine with benzoyl chloride at 75 for 72 hours. A mixture of di- and tribenzoates is said to result. The separated tribenzoate is soluble in pyridine, acetone, and chloroform, but is insoluble in alcohol and ether. In chloroform its optical rotation is Ca]o +80 . After starch is swollen in pyridine, the addition of benzoyl chloride causes a slow benzoylation at room temperature. The tribenzoate is produced in about twelve days. 

Reich and Damansky claim that cinnamoyl chloride in pyridine reacts slowly with dry starch when heated to 75 , and produces a mixture of di- and tricinnamate. 

Other derivatives, such as the 3,4-dichlorobenzenesulfonyl ester of starch, have also been prepared by treating starch with the acid chloride in the presence of sodium hydroxide. 

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