Experimental Study Of The Sodium Formate Thermal Dehydrogenation Behavior

Sodium formate synthesis method is widely used in the manufacturing of oxalic acid in our country. This process requires strict reaction conditions with several side reactions accompanying, so this step is the key step in the synthesis technology. Through a serial of well designed experiments, by using of thermal analysis method, the influence of heating rate, the range of temperature, the heating time, the different atmosphere and the content of NaOH in the raw material were carefully studied, and the results showed that:(1) Solid sodium formate is melt at about 253℃; The lower limit temperature of dehydrogenation process is 320℃, and the temperature range is from 320℃to 440℃; Sodium formate heating and decomposition to sodium oxalate and sodium carbonate, and two reactions are competed each other in this process, and faster heating rate is benefit to the main reaction. The high limit temperature of dehydrogenation process is 500℃. Sodium oxalate may decompose to sodium carbonate above this temperature limit.(2) The heating time of dehydrogenation process should be 30-40 minutes. It would enable sodium formate be well heated, and avoid sodium oxalate be over decomposed.(3) The proportion of main reaction and by-reaction will change in different atmosphere. Inert gases like Ar and N₂ are benefit to the main reaction. O₂ is benefit to the side reaction.(4) The existence of proper content of NaOH could contribute to increasing the yield of sodium oxalate. The yield of sodium oxalate will be increased by 13.43% when add in 4% NaOH to the raw material.(5) The above experiments information will be helpful to the design of new style reactor, and benefit to the progress of the whole technology.