PREPARATION AND PROVISION OF HIGH ASSAY DECABROMODIPHENYLETHANE

High assay reaction-derived decabromodiphenylethane product is produced and provided. The process comprises feeding diphenylethane, a partially brominated diphenylethane, or both subsurface into the liquid phase of a reaction mixture formed from components comprising excess liquid bromine and aluminum-based Lewis acid bromination catalyst. The temperature of the reaction mixture, the catalyst concentration in the excess bromine in the reaction mixture, and the feed time are coordinated in the processes to produce high assay reaction-derived decabromodiphenylethane product. Ways of effecting such coordination are described.