Views:2 Author:Site Editor Publish Time: 2021-12-31 Origin:Site
Oxalic acid was heated in anhydrous glycerol and steam distilled.
Or hydrolyze isoacetonitrile under the action of hydrochloric acid to obtain:
Isoacetonitrile was prepared by the reaction of ethylamine and chloroform. (This reaction must be carried out in a fume hood because of the unpleasant smell of isoacetonitrile.)
1. Sodium formate method: carbon monoxide and sodium hydroxide solution in 160-200℃ and 2MPa pressure reaction to generate sodium formate, and then by sulfuric acid acid hydrolysis, distillation of the finished product. 
2. Methanol carbonyl synthesis (also known as methyl formate method) : methanol and carbon monoxide react in the presence of sodium methoxide catalyst to generate methyl formate, and then through hydrolysis to formic acid and methanol. Methanol can be recycled into methyl formate reactor and formic acid can be rectified to get different specifications of products. 
3. Formamide method: carbon monoxide and ammonia react in methanol solution to generate formamide, and then hydrolysis in the presence of sulfuric acid to formic acid, at the same time by-product ammonium sulfate. Raw material consumption quota: methanol 31 kg/t, carbon monoxide 702 kg/t, ammonia 314 kg/t, sulfuric acid 1010 kg/t. In addition, butane oxidation of light oil is mainly used to produce acetic acid, and formic acid is recycled as a by-product. The methods in the research stage include carbon monoxide and water direct synthesis.
Refining method: anhydrous formic acid can be obtained by direct fractionation under pressure, and cooled and condensed with ice water during fractionation. For hydrous formic acid, boron anhydride or anhydrous copper sulfate can be used as a desiccant. Phosphorus pentoxide and calcium chloride can react with formic acid and should not be used as desiccant. For reagent grade 88% formic acid, water can be removed by distillation of phthalic anhydride after reflux for 6 hours. Further purification can be achieved by fractional crystallization. When formic acid and acetic acid are mixed together, fatty hydrocarbons can be added for azeotropic distillation separation.
4. The right amount of carbon monoxide and sodium hydroxide aqueous solution at 160 ~ 200 ℃ reaction to generate sodium formate, after neutralization, distillation, condensation. Or in triethylamine aqueous solution, palladium complex as catalyst, carbon dioxide and hydrogen reaction at 140 ~ 160℃.
5. Sodium formate and concentrated sulfuric acid action to get industrial grade formic acid, and then can be used after activated carbon adsorption vacuum distillation to get pure products, can also add B2O3CuSO4 vacuum distillation refining.
6. Carbon dioxide method: palladium complex catalysis, in triethylamine aqueous solution, carbon dioxide and hydrogen reaction at 140 ~ 160 ℃.
7. Synthetic acidification method and high pressure catalysis method are mainly used. Synthetic acidification method: the carbon monoxide produced by coke combustion and sodium hydroxide synthesis of sodium formate, then sulfuric acid acidification, distillation and obtained. High pressure catalysis method: carbon monoxide and water vapor in the presence of catalyst, reaction under high temperature and high pressure.
8. The formic acid and phosphorus pentoxide mixed, vacuum distillation, repeated 5-10 times, can get anhydrous formic acid, but the amount is low, time-consuming, will cause some decomposition. Formic acid and boric acid drunk distillation, simple operation, better effect. The boric acid is placed in the oven and dehydrated at medium and high temperature until bubbles are no longer generated. The molten material is poured onto the iron sheet, cooled in a dryer, and then ground into powder. Add borate phenol powder to formic acid, place for a few days, form a hard block, separate clear liquid for vacuum distillation, collect 22-25 ℃/12-18 mm distillate as the product. The distiller shall be a full mill joint protected by a drying pipe
Formic acid is also a very mature chemical product in The Chinese market, and the formic acid content is 99% and 85% respectively. However, the recent high price of formic acid is also unstable. How will the market change in the later period. If you have any purchase requirement, please make an inquiry to us.