What Is Chloroacetic Acid Definition Reactions Preparation and Applications
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.
FAQs on Chloroacetic Acid Structure Properties Preparation and Uses
1. What is chloroacetic acid?
Chloroacetic acid is a chlorinated derivative of acetic acid with the chemical formula ClCH2COOH, where one hydrogen atom in the methyl group is replaced by chlorine.
It is also known as monochloroacetic acid (MCA) and belongs to the class of haloacetic acids. The presence of the electronegative chlorine atom increases its acidity compared to acetic acid.
- Molecular formula: C2H3ClO2
- Functional groups: –COOH (carboxylic acid) and –Cl (chloro substituent)
2. What is the structure of chloroacetic acid?
The structure of chloroacetic acid consists of a carboxyl group (–COOH) attached to a chloromethyl group (–CH2Cl).
Its structural formula can be written as:
- Cl–CH2–COOH
The molecule contains:
- A polar carboxylic acid functional group
- A chlorine atom that exerts a strong –I (inductive) effect, increasing acidity
3. Why is chloroacetic acid stronger than acetic acid?
Chloroacetic acid is stronger than acetic acid because the chlorine atom withdraws electron density through the –I inductive effect, stabilizing the conjugate base.
When chloroacetic acid dissociates:
- ClCH2COOH(aq) ⇌ ClCH2COO−(aq) + H+(aq)
The electron-withdrawing chlorine stabilizes the carboxylate ion, making proton release easier. Its pKa (~2.86) is lower than that of acetic acid (~4.76), indicating higher acidity.
4. How is chloroacetic acid prepared?
Chloroacetic acid is commonly prepared by the chlorination of acetic acid in the presence of a catalyst.
The reaction is:
- CH3COOH(l) + Cl2(g) → ClCH2COOH(l) + HCl(g)
Key points:
- Catalyst: red phosphorus or UV light
- This is a substitution reaction at the α-carbon
- Excess chlorination can produce dichloro- and trichloroacetic acids
5. What are the physical properties of chloroacetic acid?
Chloroacetic acid is a white crystalline solid with high solubility in water and a sharp, pungent odor.
- Molar mass: 94.50 g·mol−1
- Melting point: ~63°C
- Boiling point: ~189°C
- Highly soluble in water due to hydrogen bonding
It is corrosive and must be handled with proper laboratory safety precautions.
6. What are the chemical properties of chloroacetic acid?
Chloroacetic acid shows typical carboxylic acid reactions along with nucleophilic substitution due to the presence of chlorine.
- Acid–base reaction: ClCH2COOH + NaOH → ClCH2COONa + H2O
- Esterification: ClCH2COOH + C2H5OH → ClCH2COOC2H5 + H2O
- Nucleophilic substitution: The –Cl can be replaced by –OH, –NH2, etc.
These reactions make it an important intermediate in organic synthesis.
7. What is the difference between chloroacetic acid and acetic acid?
The main difference between chloroacetic acid and acetic acid is that chloroacetic acid contains a chlorine substituent, making it more acidic.
- Acetic acid: CH3COOH
- Chloroacetic acid: ClCH2COOH
- Acidity: Chloroacetic acid (pKa ≈ 2.86) > Acetic acid (pKa ≈ 4.76)
- Reason: Stronger electron-withdrawing effect of chlorine
Thus, chloroacetic acid ionizes more readily in aqueous solution.
8. What are the uses of chloroacetic acid?
Chloroacetic acid is widely used as a chemical intermediate in pharmaceuticals, agrochemicals, and industrial products.
- Production of carboxymethyl cellulose (CMC)
- Synthesis of herbicides such as 2,4-D
- Manufacture of dyes and surfactants
- Preparation of glycine via reaction with ammonia
Its reactivity at the chloro-substituted carbon makes it valuable in organic synthesis.
9. How does chloroacetic acid react with ammonia?
Chloroacetic acid reacts with ammonia to form glycine (aminoacetic acid) through nucleophilic substitution.
The balanced reaction is:
- ClCH2COOH + 2NH3 → NH2CH2COOH + NH4Cl
One molecule of ammonia substitutes the chlorine, while another neutralizes the HCl formed, producing ammonium chloride.
10. Is chloroacetic acid hazardous?
Yes, chloroacetic acid is a highly corrosive and toxic chemical that can cause severe burns and systemic toxicity.
- Causes skin and eye burns
- Harmful if inhaled or ingested
- Requires gloves, goggles, and proper ventilation
Due to its strong acidity and reactive chlorine group, it must be handled under strict laboratory safety protocols.
