Chloroacetic acid, Chloro Acetate, Chloro Acetic acid, Mono Chloro Acetic acid, 79-11-8

Chloroacetic acid, Chloro Acetate, Chloro Acetic acid, Mono Chloro Acetic acid, 79-11-8

CAS: 79-11-8

Molecular Formula: C2H3ClO2

Names and Identifiers

Physico-chemical Properties

Risk and Safety

Upstream Downstream Industry

Nature

colorless or light yellow crystals, irritating odor, easy deliquescence. Strong corrosive, can corrode the skin, damage all non-precious metals, rubber and wood. Soluble in water and ethanol, ether and other most organic solvents. There are four types of crystals.

Preparation Method

1. acetic acid chlorination glacial acetic acid reacts with chlorine gas at about 95 ℃ under sulfur catalysis to obtain chloroacetic acid product, which is then cooled, crystallized and filtered to remove the mother liquor to obtain the final cyanacetic acid product. The tail gas is sent to the absorption tower to recover hydrochloric acid.
2. hydrolysis of trichloroethylene
3. glycolic acid chloride method

Use

This product is an organic chemical raw materials, mainly used as pesticides, pharmaceuticals and dyes intermediates. Pesticide industry for the production of dimethoate, herbicide 2,4-D and butyl ester, 2,4 ,5-T, thiocyanacetic acid and a naphthalene acetic acid; Pharmaceutical industry for the synthesis of caffeine, barbiturate, epinephrine, vitamin B. And glycine; Used in the dye industry for the production of indigo dyes. Chloroacetic acid can also be used in the production of carboxymethyl cellulose (CMC) and non-ferrous metal flotation agent 2-200#, can also be used as a chromatographic analysis reagent.

Safety

• This product is highly toxic, has strong irritation and corrosiveness, can cause burns infected with the skin, long-term exposure to its vapor can lead to olfactory dysfunction, Chronic nasopharyngitis, skin itching, dryness and desquamation. The rats were gavage with 10% solution with an LDso of 55mg/kg. Production equipment should be closed to prevent leakage. Operators should wear protective equipment, and the skin or eyes should be washed with plenty of water.
• woven bag lined with plastic bag, 25kg or 50kg net weight of each bag. It can also be packed in PVC plastic barrels. Store in a cool and dry place to prevent rain and humidity. According to the general provisions of the storage and transportation of chemicals.

Supplementary Information

category
High toxicity grade
Acute oral toxicity-rat LD50: 580 mg/kg; Subcutaneous-mouse LD50: 250 mg/kg
Explosive hazard characteristics and explosive properties of air mixture
Flammable hazard characteristics: when exposed to heat, open flame combustion; Toxic phosgene generated by thermal decomposition; Corrosive
Storage and Transportation characteristics the warehouse is ventilated and dried at low temperature; It is stored separately from oxidants and alkalis.
Fire extinguishing agent foam, water mist, carbon dioxide
Occupational Standards TLV-TWA 0.5 mg/m; PEL 1 mg/m

 Production method

There are three main methods for industrial production of chloroacetic acid

1. The acetic acid chlorination method is obtained by directly chlorination of acetic acid with chlorine gas in the presence of a catalyst such as iodine, phosphorus, sulfur or a halide of phosphorus and sulfur. In addition to the formation of chloroacetic acid, there are deep chlorination by-products such as dichloroacetic acid, trichloroacetic acid. The process is simple and the yield of chloroacetic acid can reach 92%.
2. The trichloroethylene hydration method uses 93% sulfuric acid as a catalyst, and the reaction temperature is about 160-180 °c. Chloroacetic acid with high purity can be obtained by this method, and the yield can reach 90%, but more hydrochloric acid is by-product.
3. The chloroethanol oxidation method was performed at 60 ° C. With 60% nitric acid, and the yield of chloroacetic acid was more than 90%. In North America to acetic acid chloride method, Western Europe to trichloroethylene water law.

China's production by acetic acid chlorination method: the quantitative glacial acetic acid is added to the reaction pot, with 3.5% sulfur powder by weight of glacial acetic acid as the catalyst, preheating to more than 90 ℃, and the appropriate amount of chlorine gas is introduced, two reaction pots were connected to each other with chlorine. The main pot was controlled at 98±2 ℃, and the auxiliary pot was controlled at 85-90 ℃, when the relative density of the materials in the reaction pan is 1.350(80 ° C.), the end point of the reaction is reached. The reactant is pumped to the acid tank, cooled and crystallized, and the liquid phase is a small amount of acetic acid, dichloroacetic acid, sulfur chloride and a small amount of chloroacetic acid. The crystal is separated and the mother liquor is pumped down to 38 ℃. About 150 of mother liquor is produced per ton of product and can be further chlorinated to dichloroacetic acid, methyl dichloroacetate and chloroform. Trichloroethylene water method at the same time the addition of water and hydrolysis: the reaction temperature of 160-180 deg C, the reaction concentration of sulfuric acid should be maintained at 93%, control the ratio of trichloroethylene and water. The consumption of sulfuric acid is not more than 30%, and 2.57t hydrochloric acid is produced as by-product. Industrial chloroacetic acid is colorless or slightly yellowish crystals. Raw material consumption quota: glacial acetic acid (98%)730kg/t, chlorine 860kg/t, sulfur 26kg/t.

• There are many synthetic methods of chloroacetic acid, such as acetic acid chlorination, acetic anhydride catalyzed chlorination, trichloroethylene hydrolysis, glycolic acid chlorination, tetrachloroethane hydrolysis, etc. Acetic acid chlorination is mainly used in domestic industrial production, the advantage of this method is that no sulfuric acid is used, and the raw material price is cheap, CH3COOH + Cl2 & rarr;ClCH2COOH + HCl
• add quantitative glacial acetic acid into the reaction pan, use 3.5% sulfur powder of glacial acetic acid mass as catalyst, preheat to above 90 ℃, start feeding appropriate amount of chlorine gas, and connect the two reaction pans with each other, the temperature of the main pot was controlled at (98±2)℃, and the temperature of the auxiliary pot was 85-90 ℃, and the chlorine gas flow rate was about 70kg/h. When the relative density of the materials in the reaction pot is 1.350(80 ° C.), the end point of the reaction is reached. The reactants were pumped to the acid tank, cooled to crystallize, the crystals were separated, and the mother liquor was drained below 38 °c to obtain the finished chloroacetic acid. In addition, some experiments show that, in addition to sulfur powder, acetic anhydride can also play a good catalytic effect on the above chlorination reaction under the same conditions, and the effect is better than that of sulfur powder.
• also trichloroethylene water legal. Trichloroethylene reacts with concentrated sulfuric acid, the reaction temperature is 160~180 ℃, the sulfuric acid content is maintained at 93%, the ratio of trichloroethylene to water is controlled, and the reaction process is added and hydrolyzed with sulfuric acid to obtain monochloroacetic acid.

Reference Information