Production method: 55 g pentathritol (0.40 mol), 200g40% hydrobromic acid solution (1.0 mol) and a certain amount of ice acetic acid were added into a 500 ml three-mouth bottle equipped with an electric mixer, a thermometer and a reflux condenser. Start the mixer, slowly heating, reaction at reflux temperature for 6 ~ 8 h. At the end of the reaction, the water and unreacted hydrogen bromide were removed under reduced pressure, and then 300 ml of the same volume of toluene and water were added for stirring treatment for 3 h. Filter, recrystallize with hot water, and decolorize with activated carbon. After filtration and vacuum drying, 84.7 g of finished product was obtained, and the yield (measured by pentaerythritol) was 80.8%.

Usage: 1. A reactive flame retardant, which can achieve a more strict flame retardant effect after use. 2. Intermediates of organic synthesis