Chloroacetic Acid

What is Chloroacetic Acid

Chloroacetic acid is a chloro-carboxylic acid synthesized in the laboratory and commonly referred to as a mono-chloroacetic acid (MCA) or Chloroethanoic acid or 2-Chloroacetic acid. Chloroacetic acid carries a 2-chloro substituent. It functions as an alkylating agent and a herbicide. Hence, it functions not only as a chloro-carboxylic acid but also as a haloacetic acid. It’s derived from acetic acid and is a conjugate of a chloroacetate.

Felix LeBlanc first prepared chloroacetic acid or Chloroethanoic acid, French Chemist in the year 1843 by chlorinating acetic acid (CH3COOH) in the presence of sunlight. In 1857, Charles-Adolphe Wurtz, a French Chemist, also prepared Chloroacetic acid by reacting chloroacetyl chloride with water. In the same year, Reinhold Hoffmann, a German Chemist prepared Chloroethanoic acid by refluxing glacial acetic acid in the presence of sunlight and chlorine.  

Structure of Chloroacetic Acid

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Molecular Structure of Chloroacetic Acid

Chloroacetic acid is a light-brownish or colourless crystalline solid that sinks or dissolves easily in water. The chloroacetic acid formula is C2H3ClO2, and the molar mass is 94.49 g·mol−1. The Chloroethanoic acid is a combustible and corrosive compound that becomes toxic when ingested, absorbed, inhaled, or penetrated through the skin barrier. The chloro-carboxylic acid causes thermal when transported in its molten state.

Properties of Chloroacetic Acid

Here, are a few physical and chemical properties of the Chloroacetic Acid-

Physical Properties

• Chloroacetic acid is a colourless or light-brownish coloured, crystalline, and hygroscopic solid.

• Chloroethanoic acid presents high solubility in water and has relatively good solubility in solutions like diethyl ether, methanol, acetone, or ethanol. However, it is sparingly soluble in chlorinated hydrocarbons and hydrocarbons solutions.

• Chloroacetic acid molar mass is 94.49 g/mol, and density is 1.58 g/cm3.

• Chloroacetic acid forms azeotropes with several organic compounds.

• The boiling point of Chloroacetic acid is 189.3 °C, while the melting point of Chloroacetic acid is 63 °C.

Chemical Properties

• Chloroacetic acid is a common synthetic organic intermediate, either as the acid itself or as an acid derivative.

• Chloroethanoic acid reacts with inorganic oxides, bases, and carbonates or with organic bases to give salts. Sodium chloroacetate is an important commercial product produced.

• Chloroacetic acid esters are obtained by reaction with alcohols or olefins, which are also industrially important.

• Chloroacetyl chloride is a product from the acid reaction with POCl3, PCl3, PCl5, thionyl chloride (SOCl2), phosgene (COCl2), etc.

Why Is Chloroacetic Acid Stronger Than Acetic Acid?

Chloroacetic acid is stronger than acetic acid because- the presence of chlorine. The −Cl ion is an electron-withdrawing group that pulls the negative charge towards itself, causing an inductive effect. 

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Inductive effect experienced by chloroacetic acid

This effect leads to the negatively charged density on the oxygen atom to reduce, hence stabilizing the conjugate base of chloroacetic acid. 

In chloroacetic acid, the strongly electron-withdrawing or electron affinity chlorine gets instantly replaced by a hydrogen atom and becomes 100 times stronger as an acid rather than an acetic acid, and the nitroacetic acid formed becomes stronger than the latter.

Chloroacetic Acid Uses

• Chloroacetic acid is manufactured in several hundred thousand tons as carboxymethyl cellulose CMC, commonly known as Cellulose Ethers.

• The primary application of chloroethanoic acid is the production of herbicides based on aryl hydroxy acetic acids, commonly known as Chloro Phenoxy Alkanoic Acids. These herbicides have a broad spectrum of usage.

• Methyl chloroacetate and Chloroacetic acid are an essential constituent employed for the preparation of insecticide- dimethoate and herbicides- benazoline and methyl b-naphthyl acetate.

• Another important outlet for Chloroethanoic acid is the manufacture of thioglycolic acid prepared in large amounts and employed to produce stabilizers for polyvinyl chloride or PVCs. Another practical use of thioglycolic acid is in hair cosmetics for hair preparations.

• Another significant importance of chloroacetic acid is in the production of N-lauryl betaine, a long-chain betaine, which is used as cleaning surfactants or in personal care products.

Health Hazards of Chloroacetic Acid 

• When inhaled or breathed in, chloroacetic acid can irritate the throat, lungs, and nose causing coughing, shortness of breath, and wheezing.

• Chloroacetic acid is a corrosive chemical, and when it comes in contact with skin and eyes can cause severe irritation, burning sensation, and can even damage the eye.

• High or repeated exposure to chloroacetic acid can affect kidneys.

• High exposure to Chloroethanoic acid can cause blurred visions, muscle twitching, ‘pins and needles’, anxiety, restlessness, and hallucinations. However, excessive intake can lead to convulsions and even lead to death.