Method of microwave dehydrogenation for producing sodium oxalate

Abstract

A process for preparing sodium oxalate by microwave dehydrogenation features that after the solution or solid of sodium formate is added to the microwave resonance cavity, it is quickly heated to 350-450 deg.C by microwave, so decreasing the generation of by-reaction at 280-380 deg.C. Its advantages are high output rate and easy control to temp.

Description

technical field [0001] The invention belongs to the technical field of organic chemical industry and carboxylate production, in particular to the technology of producing oxalic acid by synthetic method. Background technique [0002] Oxalic acid is an important chemical raw material. At present, oxalic acid is mostly produced by synthetic method, and the dehydrogenation process is one of the important processes in the production of oxalic acid by synthetic method. [0003] The basic chemical principle of dehydrogenation production is: the 25% sodium formate solution produced in the synthesis process is concentrated and put into the dehydrogenation pot for heating. Sodium endoformate decomposes under normal pressure to generate sodium oxalate and hydrogen. The chemical reaction formula of the dehydrogenation process is [0004] <chemistry num="001"> <chem file="200410040303_CML001.XML" / > < / chemistry> [0005] At present, the existing dehydrogenation me...

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Problems solved by technology

[0007] (1) Serious energy loss

[0008] The thermal efficiency of coal combustion in the furnace is low, the heat dissipation of the pot body, and the heat dissipation of sodium formate exposed to the air

[0009] (2) Low yield

[0013] Obviously, the slower the heating rate is, the longer the time of going through this temperature range is, the higher the conversion rate of this side reaction is, and the lower the yield of the positive reaction will be

[0014] ②Because the sodium formate in the pot is exposed to the atmosphere, the temperature of the material in the bottom and the upper part is inconsistent. When the bottom sodium formate reaches the dehydrogenation temperature, the middle and upper parts have not yet reached the same temperature, that is, the lower part reacts and the upper part does not react, which affects the yield.

Adding a blender helps a bit with this problem, but doesn't solve the root problem

[0017] (3) The operating environment is harsh and the labor intensity of the workers is high

[0018] A general-scale dehydrogenation section operates several dehydrogenation pots at the same time. Since the time of the dehydrogenation reaction cannot be predicted and accurately controlled, it is impossible for each dehydrogenation pot to heat, add water to cool, and feed the time in a consistent or orderly manner. It is impossible to realize the automation of coal addition and ash removal. Operators need to rely on shovels to add coal and ash removal. The operating environment is harsh and the labor intensity of workers is high.

[0019] (4) Safety issues

[0020] The dehydrogenation pot is open and heated by an open flame under the pot. The wall of the stove pot is easily cracked, and it is not easy to be found and remedied after the burnt. and equipment injury and damage

[0021] (5) The equipment is seriously damaged

[0022] Heating with an open flame, the double solidification of the dehydrogenation process makes the bottom of the pot very hot, and the bottom of the pot is often burnt up, and the bottom, wall, stove and furnace mouth are also easily burned out. The flue gas temperature is high, causing Reduced fan life

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