Formation of sodium oxalate by thermal decomposition of sodium formate
ZHANG WeiWei CHEN XiaoChun LIU ZhaoWen SUN Wei LIU ShiWei (College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China)
The thermal decomposition of sodium formate, HCOONa, has been studied by thermogravimetric and differential thermal analyses. The products of thermal decomposition were analyzed by titrimetry. It was shown that after melting at 253 ℃, sodium formate slowly decomposes by hydrogen loss to Na2CO3, CO and Na2C2O4 at 330 ℃. The rate of the decomposition reaction increases markedly at 400 ℃, associated with a large exothermic change. Sodium oxalate subsequently decomposes to sodium carbonate on heating above above 440 ℃. It was found that both the heating rate and maximum temperature have a significant effect on the yield of sodium oxalate. In order to maximize the yield of sodium oxalate, sodium formate should heated as rapidly as possible in order to shorten the reaction time, with the optimum temperature of thermal decomposition being from 400 ℃ to 420 ℃. Overheating may cause decomposition of the sodium oxalate.