Modification of starch by reaction with ethylene oxide in liquid-solid and gas-solid reactors

The hydroxyethylation of starch in a gas-solid system has been compared economically with a slurry process with recycle of ethylene oxide. The estimated production costs with the gas-solid process turn out to be lower than the estimated costs resulting from the slurry process. The main causes for the improved economics of the gas-solid process in this preliminary study are a higher selectivity and a less complex flow scheme, relative to the slurry process. Additional research is necessary to check whether the properties of the hydroxyethylated starch obtained with the two processes are comparable