2-Chloropropane
[CAS# 75-29-6]

Identification

• Classification: Organic raw materials >> Hydrocarbon compounds and their derivatives >> Hydrocarbon halide
• Name: 2-Chloropropane
• Synonyms: Isopropyl chloride
• Molecular Formula: C₃H₇Cl
• Molecular Weight: 78.54
• CAS Registry Number: 75-29-6
• EC Number: 200-858-8
• SMILES: CC(C)Cl

Properties

• Density: 0.9±0.1 g/cm³ Calc.^*, 0.859 g/mL (Expl.)
• Melting point: -118 ºC (Expl.)
• Boiling point: 37.3±8.0 ºC 760 mmHg (Calc.)^*, 34 - 36 ºC (Expl.)
• Flash point: -35.0 ºC (Calc.)^*, -21 ºC (Expl.)
• Solubility: water 3.1 g/L (20 ºC) (Expl.)
• Index of refraction: 1.379 (Calc.)^*, 1.378 (Expl.)

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS02;GHS07 DangerGHS02
• Hazard Statements: H225-H302-H312-H332
• Precautionary Statements: P210-P233-P240-P241-P242-P243-P261-P264-P270-P271-P280-P301+P317-P302+P352-P303+P361+P353-P304+P340-P317-P321-P330-P362+P364-P370+P378-P403+P235-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Flammable liquids	Flam. Liq.	2	H225
Acute toxicity	Acute Tox.	4	H302
Acute toxicity	Acute Tox.	4	H312
Acute toxicity	Acute Tox.	4	H332
Substances or mixtures corrosive to metals	Met. Corr.	1	H290
Skin irritation	Skin Irrit.	2	H315
Specific target organ toxicity - single exposure	STOT SE	2	H371
Eye irritation	Eye Irrit.	2	H319
Specific target organ toxicity - repeated exposure	STOT RE	2	H373
Flammable liquids	Flam. Liq.	1	H224

• Transport Information: UN 2356

Discovory and Applicatios

2-Chloropropane, also known as isopropyl chloride, is a secondary alkyl halide with the molecular formula C₃H₇Cl. It is a colorless, flammable liquid with a characteristic ether-like odor. As a haloalkane, it contains a chlorine atom attached to the secondary carbon of a propyl group, which gives it distinct chemical reactivity, including nucleophilic substitution and elimination reactions. Its secondary carbon center affects its steric accessibility and influences the reaction pathways it undergoes compared with primary or tertiary halides.

The discovery of 2-chloropropane is linked to early studies of alcohol halogenation. It was initially synthesized by reacting isopropanol with hydrochloric acid under acidic conditions, where the hydroxyl group is substituted by a chlorine atom. Later improvements included the use of thionyl chloride or phosphorus pentachloride as chlorinating agents to provide higher yields and purities while minimizing side reactions. These methods established practical procedures for both laboratory-scale and industrial production of 2-chloropropane.

2-Chloropropane finds extensive use as an intermediate in organic synthesis. Its secondary chloride group allows it to act as an alkylating agent for nucleophiles, enabling the construction of isopropyl-substituted molecules. In pharmaceutical chemistry, it is utilized to synthesize intermediates for drugs, where isopropyl substitution can modify biological activity, solubility, and metabolic stability. It is also used in the preparation of agrochemicals, providing a route to herbicides, insecticides, and fungicides that contain the isopropyl group.

In polymer and materials chemistry, 2-chloropropane can be used to introduce branching or functional groups into polymer backbones through substitution reactions. This modification can improve polymer properties such as solubility, flexibility, and reactivity for subsequent chemical transformations. In research laboratories, 2-chloropropane serves as a model compound for studying S_N1 and S_N2 reaction mechanisms, as its secondary carbon allows for both substitution and elimination pathways depending on reaction conditions.

Mechanistically, 2-chloropropane undergoes nucleophilic substitution through both S_N2 and S_N1 pathways. Steric hindrance at the secondary carbon makes S_N2 reactions slower than for primary chlorides, particularly with bulky nucleophiles, while polar protic solvents and weak nucleophiles can favor carbocation formation and S_N1 reactions. Under basic conditions, 2-chloropropane can also undergo dehydrohalogenation to form propene. This combination of reactivity makes it a valuable reagent for exploring organic reaction mechanisms.

Physically, 2-chloropropane is slightly soluble in water and miscible with many organic solvents such as alcohols, ethers, and hydrocarbons. It is highly flammable and volatile, requiring careful storage in cool, well-ventilated areas away from sources of ignition. Safety precautions are important because 2-chloropropane can be harmful if inhaled, ingested, or absorbed through the skin. Proper personal protective equipment and adherence to disposal protocols are essential when handling this chemical.

Overall, 2-chloropropane is a versatile secondary alkyl halide with important applications in organic synthesis, pharmaceuticals, agrochemicals, and polymer chemistry. Its ability to undergo substitution and elimination reactions, along with its utility in introducing isopropyl groups, makes it an essential reagent in both research and industrial contexts.

References

2024. Synthesis and Biological Evaluation of 1,3,5-Dithiazinanes: Synthesis, Stereochemistry and Applications. S-Heterocycles.
DOI: 10.1007/978-981-97-4308-7_5

2023. Biological potential of vinyl/allyl substituted imidazole-based N-heterocyclic carbene adducts: synthesis, spectral and X-ray crystallographic structural characteristics. Chemical Papers, 77(12).
DOI: 10.1007/s11696-023-03126-2

2022. Deoxygenative alkylation of tertiary amides using alkyl iodides under visible light. Science China Chemistry, 65(9).
DOI: 10.1007/s11426-022-1331-y