Formic acid Methanoic acid

Physicochemical property
Flammable. It can be miscible with water, ethanol, ether and glycerol, and most polar organic solvents, and also has a certain solubility in hydrocarbons.

The relative density (d204) is 1.220. Refractive index

1.3714. The combustion heat is 254.4 kJ/mol, the critical temperature is 306.8 ℃, and the critical pressure is 8.63 MPa. Flash point 68.9 ℃ (open cup). Density 1.22, relative vapor density 1.59 (air =1), saturated vapor pressure (24℃) 5.33kPa.

High concentrations of formic acid tend to freeze in winter.

Forbidden compounds: strong oxidant, strong alkali, active metal powder.

Dangerous characteristics: the vapor and air form an explosive mixture, which causes combustion and explosion in case of open fire and high heat energy. Reacts with strong oxidants.

Solubility: miscible with water, insoluble in hydrocarbons, miscible in alcohol.

In hydrocarbons and gaseous states, formic acid occurs as dimers bonded by hydrogen bonds. In gaseous state, hydrogen bonding results in a large deviation between formic acid gas and ideal gas equation of state. Liquid and solid formic acid consists of continuous formic acid molecules bonded by hydrogen bonds.

Formic acid is decomposed into CO and H2O under the catalysis of concentrated sulfuric acid:

Because of the special structure of formic acid, one of its hydrogen atoms is directly connected to the carboxyl group. Or you could view it as a hydroxyformaldehyde. Thus formic acid has both acid and aldehyde properties.

Formic acid has the same properties as most other carboxylic acids, although under normal circumstances formic acid does not form an acyl chloride or anhydride. Dehydration decomposes formic acid into carbon monoxide and water. Formic acid has similar reducing properties to aldehydes. It can initiate a silver mirror reaction, reducing the silver ions in the silver ammonia complex ions to silver metal, and itself is oxidized into carbon dioxide and water:

Formic acid is the only carboxylic acid that can be added to olefins. Formic acid in the action of acids (such as sulfuric acid, hydrofluoric acid), and olefins quickly react to form formates. However, a side reaction similar to the Koch reaction can also occur, with the product being a higher carboxylic acid.

Pair value of octanol/water partition coefficient: -0.54, upper explosion limit % (V/V) : 57.0, lower explosion limit % (V/V) : 18.0.

Formic acid is a strong reducing agent and silver mirror reaction can occur. It is the most acidic in saturated fatty acids, and the dissociation constant is 2.1×10-4. It slowly breaks down into carbon monoxide and water at room temperature. It is heated to 60~80℃ with concentrated sulfuric acid to decompose and release carbon monoxide. When formic acid is heated above 160 ° C, it decomposes to release carbon dioxide and hydrogen. The alkali metal salts of formic acid are heated to 400 ° C to form oxalates.

Molecular structure data

1. Molar refractive index: 8.40

2. Molar volume (m/mol) : 39.8

3. Isotropic specific volume (90.2K) : 97.5

4, surface tension (dyne/cm) : 35.8

5, polarizability (10cm) : 3.33

Preparation method
Folding laboratory method
Oxalic acid was heated in anhydrous glycerol and then steam distilled.

Or hydrolyzed isoacetonitrile under the action of hydrochloric acid to obtain:

Isoacetonitrile is prepared by the reaction of ethylamine and chloroform. (Because isoacetonitrile has an unpleasant odor, this reaction must be carried out in a fume hood.)

Folding industrial process
1, sodium formate method: carbon monoxide and sodium hydroxide solution at 160-200℃ and 2MPa pressure reaction to produce sodium formate, and then acid hydrolysis by sulfuric acid, distillation to obtain the finished product.

2. Methanol carbonyl synthesis (also known as methyl formate method) : methanol and carbon monoxide react in the presence of sodium methanol as a catalyst to form methyl formate, and then hydrolysis to form formic acid and methanol. Methanol can be recycled into the methyl formate reactor, and then the formate can be rectified to obtain products of different specifications.

3, formamide method: carbon monoxide and ammonia in methanol solution reaction to formamide, and then in the presence of sulfuric acid hydrolysis to formic acid, while byproduct 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 and dinnerless light oil oxidation method is mainly used to produce acetic acid, formic acid as a by-product recovery, in the research stage of the method of direct synthesis of carbon monoxide and water.

Refining method: Anhydrous formic acid can be obtained by direct fractionation under reduced pressure. For aqueous formic acid, boron anhydride or anhydrous copper sulfate can be used as a desiccant. Phosphorus pentoxide and calcium chloride can interact with formic acid and should not be used as desiccant. For 88% of the reagent grade formic acid, the water in it can be removed by distillation of phthalic anhydride after reflux for 6 hours. Further purification can be done by fractional crystallization. When formic acid and acetic acid are mixed together, they can be separated by azeotropic distillation by adding aliphatic hydrocarbons.

4, the appropriate amount of carbon monoxide and sodium hydroxide aqueous solution at 160 ~ 200 ℃ reaction to produce sodium formate, through neutralization, distillation, condensation. Or in triethylamine aqueous solution, using palladium complex as catalyst, carbon dioxide and hydrogen gas reaction at 140 ~ 160℃.

5, the reaction of sodium formate and concentrated sulfuric acid to produce industrial-grade formic acid, and then can be adsorbed by activated carbon after vacuum distillation to produce pure products, can also be added to B2O3CuSO4 vacuum distillation refining.

6, carbon dioxide method: under the catalysis of palladium complex, in triethylamine aqueous solution, carbon dioxide and hydrogen gas reaction at 140 ~ 160 ℃.

7, the main use of synthetic acidification method and high pressure catalytic method. Synthetic acidification method: the carbon monoxide produced by coke combustion and sodium hydroxide to synthesize sodium formate, and then acidified with sulfuric acid, by distillation. High-pressure catalytic method: carbon monoxide and water vapor in the presence of catalyst, reaction at high temperature and high pressure.

8, the formic acid and phosphorus pentoxide mixed, vacuum distillation, repeated 5 to 10 times, in order to obtain anhydrous formic acid, but the amount of low, time-consuming, will cause some decomposition. The distillation of formic acid and boric acid is simple and effective. The boric acid is dehydrated at a medium high temperature until it no longer produces bubbles, and the resulting melt is poured on an iron sheet, cooled in a dryer, and then ground into powder. The fine borate phenol powder was added to the formic acid and placed for a few days to form a hard mass. The clear liquid was separated for vacuum distillation and the distillation portion of 22-25 ℃/12-18 mm was collected as the product. The still shall be fully ground joint and protected by drying pipe.

Standard

GB/T 2093-2011 Industrial formic acid

Formic acid content: phenolphthalein as indicator, titrated with sodium hydroxide solution.

Chloride: In nitric acid solution, the chloride ion in the sample and silver nitrate form silver chloride, and the standard turbidimetric solution is turbidified.

Sulfate: Sodium carbonate is added to the sample to make sulfate in formic acid, barium chloride solution is added in the presence of hydrochloric acid to make barium sulfate, and the standard turbidimetric solution is turbidified.

Iron (Fe2+) : according to GB/T 3049-2006.

Evaporation residue: according to GB/T 6026-1998.

Main use
Formic acid is one of the basic organic chemical raw materials, widely used in pesticides, leather, dyes, medicine and rubber industries. Formic acid can be directly used in fabric processing, tanning leather, textile printing and dyeing and green feed storage, and can also be used as metal surface treatment agent, rubber auxiliary and industrial solvent. In organic synthesis, it is used to synthesize various formates, acridine dyes and formamide series of medical intermediates. The specific categories are as follows:

Pharmaceutical industry: Caffeine, aminopyrine, aminophylline, theobromine borneol, vitamin B1, metronidazole, mebendazole.
Pesticide industry: powder, triazolone, tricyclozole, triamidazole, triazophos, polybulozole, tenobulozole, insecticide, dicofol and so on.
Chemical industry: calcium formate, sodium formate, ammonium formate, potassium formate, ethyl formate, barium formate, dimethylformamide, formamide, rubber antioxidant, pentaerythritol, neopentanediol, epoxy soybean oil, epoxy octyl soybean oleate, valeryl chloride, paint remover, phenolic resin, pickling steel plate, etc.
Leather industry: tanning preparations, deashing agents and neutralizing agents for leather.
Rubber industry: natural rubber coagulants.
Other: can also manufacture dyeing mordant, fiber and paper dyeing agent, treatment agent, plasticizer, food preservation and animal feed additives.
Make CO. Chemical formula: HCOOH= (concentrated H2SO4 catalysis) heating =CO+H2O
A reducing agent. Determination of arsenic, bismuth, aluminum, copper, gold, indium, iron, lead, manganese, mercury, molybdenum, silver and zinc. Verification of cerium, rhenium and tungsten. Testing aromatic primary and secondary amines. Determination of relative molecular weight and crystallization solvent. Methoxy group was determined. Used as fixative in microscopic analysis. Make formates.
Formic acid and its aqueous solution can dissolve many metals, metal oxides, hydroxides and salts, and the resulting formates can be dissolved in water, so they can be used as chemical cleaning agents. Formic acid does not contain chloride ions and can be used for cleaning equipment containing stainless steel materials.

Safety information
Packing grade: II
Danger category: 8
Customs Code: 2915110000
Dangerous Goods transport code: UN11983/PG3
WGKGermany: 2
Danger category code: R35
Safety Description: S36/37-S45-S26-S23-S36/37/39
RTECS number: LP8925000
Dangerous goods mark :C :Corrosive

Pls input...