Vinylbenzyl chloride
[CAS 30030-25-2]

Identification

• Classification: Chemical reagent >> Organic reagent >> Aromatic hydrocarbon reagent
• Name: Vinylbenzyl chloride
• Synonyms: Chloromethylstyrene; (Chloromethyl)vinylbenzene
• Molecular Formula: C₉H₉Cl
• Molecular Weight: 152.62
• CAS Registry Number: 30030-25-2
• EC Number: 250-005-9
• SMILES: C=CC1=CC=CC(=C1)CCl

Properties

• Density: 1.1$+/-$0.1 g/cm³ Calc.^*
• Boiling point: 226.4$+/-$9.0 $degree$C 760 mmHg (Calc.)^*
• Flash point: 88.8$+/-$11.4 $degree$C (Calc.)^*
• Index of refraction: 1.57 (Calc.)^*

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

Safety Data

• Hazard Symbols: GHS05;GHS06;GHS09 Danger
• Risk Statements: H302-H311-H314-H317-H400
• Safety Statements: P260-P280-P301+P312+P330-P303+P361+P353-P304+P340+P310-P305+P351+P338

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute toxicity	Acute Tox.	4	H302
Skin sensitization	Skin Sens.	1	H317
Acute hazardous to the aquatic environment	Aquatic Acute	1	H400
Acute toxicity	Acute Tox.	3	H311
Acute toxicity	Acute Tox.	4	H312
Chronic hazardous to the aquatic environment	Aquatic Chronic	1	H410
Eye irritation	Eye Irrit.	2	H319
Acute toxicity	Acute Tox.	3	H331
Skin irritation	Skin Irrit.	2	H315
Skin corrosion	Skin Corr.	1B	H314
Skin corrosion	Skin Corr.	1	H314

• Transport Information: UN 2922

Discovery and Applications

Vinylbenzyl chloride is an aromatic organic compound consisting of a benzene ring substituted with two functional groups: a vinyl group (–CH=CH₂) and a chloromethyl group (–CH₂Cl), typically in para or mixed isomer forms depending on synthesis. It belongs to the class of vinyl-substituted benzyl halides and is widely used as a reactive monomer in polymer chemistry.

The molecular structure contains two chemically distinct reactive sites on a single aromatic scaffold. The vinyl group (–CH=CH₂) can undergo free-radical polymerization, allowing formation of polymer backbones similar to polystyrene. The benzylic chloride group (–CH₂Cl) is highly reactive toward nucleophilic substitution due to stabilization of the benzylic intermediate. This dual functionality makes vinylbenzyl chloride a useful bifunctional monomer for post-polymerization modification.

Vinylbenzyl chloride became important in polymer chemistry during the mid-20th century, when researchers sought monomers capable of introducing reactive side chains into polymer networks. It enabled the preparation of polymers that could be chemically modified after polymerization, expanding the design of functional materials.

The compound is typically synthesized by chloromethylation of vinyltoluene or related styrenic precursors using formaldehyde and hydrogen chloride under acidic conditions, often with a Lewis acid catalyst. Careful control is required to prevent side reactions involving the vinyl group, which is also reactive under radical or electrophilic conditions.

In polymer applications, vinylbenzyl chloride is commonly used as a functional comonomer in free-radical polymerization with styrene, acrylates, or other vinyl monomers. The resulting polymers contain pendant chloromethyl groups that serve as reactive sites for further chemical transformation.

A major application of vinylbenzyl chloride–based polymers is in ion-exchange resins. The chloromethyl groups can be converted into quaternary ammonium groups through reaction with tertiary amines, producing strongly basic anion-exchange materials used in water purification, separations, and catalysis.

The compound is also used to prepare functional coatings, membranes, and support materials. Its chloromethyl group can react with nucleophiles such as amines, thiols, or alcohols, enabling attachment of diverse functional groups. This versatility makes it valuable in designing tailored polymer systems.

Overall, vinylbenzyl chloride is a bifunctional aromatic monomer combining a polymerizable vinyl group (–CH=CH₂) with a reactive benzylic chloride group (–CH₂Cl). Its dual reactivity underpins its importance in the synthesis of functional polymers, particularly ion-exchange resins and chemically modifiable materials.

References

2025. Research on the regulation of hydrophobic chain length on the swelling properties of hydrogels. Colloid and Polymer Science.
DOI: 10.1007/s00396-025-05533-1

2014. Synthesis of Surface Active Monomers. SpringerBriefs in Materials.
DOI: 10.1007/978-3-319-08446-6_1

1988. Preparation of PMMA macromers by o-vinylbenzylmagnesium chloride and their polymerization. Polymer Bulletin.
DOI: 10.1007/bf00255377