Chloroacetic Acid Formula

Chloroacetic acid is an organochlorine compound that happens to be a conjugate acid of chloroacetate. It is derived from acetic acid. Chloroacetic acid is a chlorocarboxylic acid that is acetic acid with a 2-chloro substituent. Industrially, this acid is known as monochloroacetic acid (MCA), whose chemical formula is C₂H₃ClO₂. The other names of this acid are chloro ethanoic acid, 2-chloro acetic acid, and 2-chloroethanoic acid. It is a haloacetic acid whose concentration of acid can be around 80%. It is an effective building block for organic synthesis. This acid in its solid form is a colorless or light-brown crystalline material, whereas in its aqueous form it is a colorless solution of the white crystalline solid. This acid is corrosive to metals and tissues. It is used as a chemical intermediate, herbicide, bacteriostat, and also as a preservative. When chloroacetic acid is heated to decomposition, it emits highly toxic and corrosive hydrogen chloride and phosgene fumes.

Structure of Chloroacetic Acid

The chemical or molecular formula of Chloroacetic acid is C₂H₃ClO₂ or ClCH₂COOH. The preferred IUPAC name for this acid is 2-Chloroacetic acid. 

Preparation of Chloroacetic Acid

Chloroacetic acid is a chlorocarboxylic acid that is acetic acid with a 2-chloro substituent. It can be prepared industrially by two methods. The most prevailing method is chlorinating acetic acid in the presence of acetic anhydride, which is a catalyst.

H₃C−COOH + Cl₂ → ClH₂C−COOH + HCl

However, impurities such as dichloroacetic acid and trichloroacetic acid form during this process that are difficult to separate by distillation, which is a drawback of this method.

H₃C−COOH + 2Cl₂ → Cl₂HC−COOH (dichloroacetic acid) + 2HCl

H3C−COOH + 3Cl₂ → Cl₃C−COOH (trichloroacetic acid) + 3HCl

The second method is by hydrolyzing trichloroethylene with sulfuric acid acting as a catalyst. This process is conducted at 130–140 °C in a concentrated (at least 75%) solution of sulfuric acid, which produces a highly pure product.

ClHC=CCl₂ + 2H₂O → ClH₂C−COOH + 2HCl

Physical Properties of Chloroacetic Acid

Chemical Formula	C2H3ClO2
Molar mass/Molecular weight	94.49 g·mol−1
Appearance	Colorless or white crystals
Odor	pungent odor like-strong vinegar
Density	1.58 g/cm3
Melting point	63 °C
Boiling point	189.3 °C
Flash point	126 °C
Solubility	Soluble in water, ethanol, diethyl ether, benzene, chloroform, and slightly soluble in carbon tetrachloride, hydrocarbons, and chlorinated hydrocarbons.
Vapor Density	6.5×10-2 mm Hg (8.68×10-3 Pka) at 25 °C

Chemical Properties of Chloroacetic Acid

• When chloroacetic acid is heated carbon dioxide and hydrogen chloride gas are formed as byproducts.

C₂H₃O₂Cl + O₂ → CO₂ + H₂O + HCl

• Chloroacetic acid reacts with sodium hydroxide (NaOH) and forms Sodium Chloroacetate and water

 C₂H₃ClO₂ + NaOH → C₂H₂O₂NaCl + H₂O

• Thioglycolic acid (C₂H₄O₂S) is prepared by the displacement of chloride by sulfide when chloroacetic acid reacts with sodium thiosulfate. Thioglycolic acid is used as a stabilizer in PVC and also as a component in some cosmetics.

ClCH₂CO₂H + Na₂S₂O₃ → Na[O₃S₂CH₂CO₂H] + NaCl
Na[O₃S₂CH₂CO₂H] + H₂O → HSCH₂CO₂H + NaHSO₄

Uses of Chloroacetic Acid

Chloroacetic Acid has a wide variety of uses some of which are listed below:

• Many reactions utilize the high reactivity of the C-Cl bond in chloroacetic acid.
• It is used as a chemical intermediate in the manufacture of ethyl chloroacetate, glycine, synthetic caffeine, sarcosine, thioglycolic acid, and EDTA.
• Chloroacetic acid is widely used to prepare the thickening agent’s carboxymethyl cellulose and carboxymethyl starch.  
• It is used as an alkylating agent, herbicide, bacteriostat, and also as a preservative. 
• It is also used in the preparation of metal derivatives and is used in the manufacturing of various dyes and drugs.
• Chloroacetic acid is used in the manufacturing of phenoxy herbicides by etherification with chlorophenols. 

Health Hazards of Chloroacetic Acid

Chloroacetic Acid is a dangerous chemical to deal with. Some of its harmful effects on health are listed below:

• Chloroacetic acid is very toxic and is a hazardous alkylating agent. Inhalation of chloroacetic acid, even for a short period, may cause severe damage to the eyes, skin, mucous membrane, and respiratory tract. 
• When it comes into contact with the skin, it causes severe burns. 
• Acute ingestion of chloroacetic acid may cause burns to the mouth and stomach and also cause perforation and peritonitis. 
• Exposure to chloroacetic acid may also lead to central nervous system depression and respiratory system depression.

FAQs on Chloroacetic Acid

Question 1: What is chloroacetic acid?

Answer:

Chloroacetic acid is an organochlorine compound that is derived from acetic acid. This is a chlorocarboxylic acid that is known as monochloroacetic acid formula, chloro ethanoic acid, or 2-Chloroacetic acid. It is an inorganic acid whose chemical formula is C₂H₃ClO₂.

Question 2: How is chloroacetic acid prepared?

Answer: 

Chloroacetic acid is a chlorocarboxylic acid that is acetic acid with a 2-chloro substituent. It can be prepared industrially by two methods. The most prevailing method is chlorinating acetic acid in the presence of acetic anhydride, which is a catalyst. The second method is by hydrolyzing trichloroethylene with sulfuric acid acting as a catalyst.

Question 3: What are the uses of chloroacetic acid?

Answer: 

Chloroacetic acid is an organochlorine compound that happens to be a conjugate acid of chloroacetate. It is used as a chemical intermediate, herbicide, bacteriostat, and also as preservative. It is also used in the preparation of metal derivatives and is used in the manufacturing of various dyes and drugs.

Question 4: Mention some properties of chloroacetic acid.

Answer: 

Chloroacetic acid is a colorless solution of the white crystalline solid whose chemical formula is C2H3ClO2. It has a pungent odor like strong vinegar and is soluble in water. It is also soluble in ethanol, diethyl ether, benzene, and chloroform, and slightly soluble in carbon tetrachloride, hydrocarbons, and chlorinated hydrocarbons. The boiling point of chloroacetic acid is 189.3 °C, while its melting point is 63.0 °C. 

Question 5:  Mention some hazards of chloroacetic acid.

Answer: 

Chloroacetic acid is very toxic. When heated to decomposition, it emits highly toxic phosgene and chloride fumes. Inhalation of chloroacetic acid, even for a short period, may cause severe damage to the eyes, skin, mucous membrane, and respiratory tract. Acute ingestion of chloroacetic acid may cause burns to the mouth and stomach.

Question 6: What happens when chloroacetic acid reacts with sodium thiosulfate?

Answer: 

Thioglycolic acid (C2H4O2S) is prepared by the displacement of chloride by sulfide when chloroacetic acid reacts with sodium thiosulfate. Thioglycolic acid is used as a stabilizer in PVC and also as a component in some cosmetics.

ClCH₂CO₂H + Na₂S₂O₃ → Na[O₃S₂CH₂CO₂H] + NaCl
Na[O₃S₂CH₂CO₂H] + H₂O → HSCH₂CO₂H + NaHSO₄