1. Sodium formate method: carbon monoxide and sodium hydroxide solution react at 160-200 ℃ and 2MPa to form sodium formate, and then the finished product is obtained by sulfuric acid hydrolysis and distillation.
2. Methanol carbonylation method (also known as methyl formate method): methanol and carbon monoxide react in the presence of sodium carbinol to form methyl formate, and then hydrolyze to form formic acid and methanol. Methanol can be recycled into methyl formate reactor, and different specifications of products can be obtained by rectification of formic acid.
3. Formamide method: carbon monoxide and ammonia react in methanol solution to form formamide, which is then hydrolyzed to formic acid in the presence of sulfuric acid, and the by-product is ammonium sulfate. Consumption quota of raw materials: methanol 31 kg / T, carbon monoxide 702 kg / T, ammonia 314 kg / T, sulfuric acid 1010 kg / T. In addition, butane light oil oxidation method is mainly used to produce acetic acid, and formic acid is recovered as a by-product.
Refining method: anhydrous formic acid can be obtained by direct fractionation under reduced pressure. During fractionation, ice water is used for cooling and condensation. For aqueous formic acid, boric anhydride or anhydrous copper sulfate can be used as desiccant. Phosphorus pentoxide and calcium chloride can react with formic acid, so they are not suitable for desiccant. For 88% formic acid of reagent grade, the water can be removed by distillation after reflux of phthalic anhydride for 6 hours. Further purification can be carried out by step crystallization. When formic acid is mixed with acetic acid, fatty hydrocarbon can be added for azeotropic distillation separation 
4. A proper amount of carbon monoxide and sodium hydroxide aqueous solution are reacted at 160-200 ℃ to form sodium formate, which is obtained by neutralization, distillation and condensation. Or in triethylamine aqueous solution, palladium complex is used as catalyst, carbon dioxide and hydrogen react at 140-160 ℃.
5. The industrial grade formic acid is prepared by the action of sodium formate and concentrated sulfuric acid, and then the pure product can be obtained by vacuum distillation after adsorption with active carbon, or the product can be refined by vacuum distillation with b2o3cuso4.
6. Carbon dioxide method: under the catalysis of palladium complex, in triethylamine aqueous solution, carbon dioxide reacts with hydrogen at 140-160 ℃.
7. Synthetic acidification and high-pressure catalysis are mainly used. Synthetic acidification: sodium formate is synthesized from carbon monoxide and sodium hydroxide produced by combustion of coke, then acidified with sulfuric acid and distilled. High pressure catalytic method: carbon monoxide and water vapor are reacted in the presence of catalyst under high temperature and pressure.
8. The anhydrous formic acid can be obtained by mixing formic acid with phosphorus pentoxide and distillation under reduced pressure for 5 to 10 times. However, the amount of anhydrous formic acid is low and takes a long time, which will cause some decomposition. The distillation of formic acid and boric acid is simple and effective. The boric acid is dehydrated at high temperature until no bubbles are produced. The molten product is poured on the iron sheet, cooled in a desiccator, and then ground into powder. The phenol borate fine powder was added to formic acid and placed for several days to form a hard block. The clear liquid was separated and distilled under reduced pressure. 22-25 ℃ / 12-18 mm fraction was collected as the product. The distiller shall be fully ground joint and protected by drying pipe.
Qingdao Hisea Chem Co.,Ltd which located in the northwest of China, is the largest salt in China, potassium chemicals production ranked fourth in the world. The main products are Glacial acetic acid, Nitric Acid, Formic Acid, Hydrogen peroxide, Potassium hydroxide, , Caustic Soda, sodium sulphide etc. annual production capacity is 6,000,000 tons. In order to increase product export, our company sets up the branch and the construction of the logistics center in Qingdao port , welcome general customers come to visit.