Methylstyrene
[CAS# 25013-15-4]

Identification

• Classification: Organic raw materials >> Hydrocarbon compounds and their derivatives >> Aromatic hydrocarbon
• Name: Methylstyrene
• Synonyms: Tolylethylene; Vinyltoluene
• Molecular Formula: C₉H₁₀
• Molecular Weight: 118.18
• CAS Registry Number: 25013-15-4
• EC Number: 246-562-2
• SMILES: CC1=CC(=CC=C1)C=C

Properties

• Density: 0.9005 g/cm³ (20 °C)^*
• Melting point: -77 °C^**
• Boiling point: 170 °C^**
• Refractive index: 1.5415 (589.3 nm 20 °C)^*

^* Mamedaliev, Yu. G.

^** "International Chemical Safety Cards" data were obtained from the National Institute for Occupational Safety and Health (US)

Safety Data

• Hazard Symbols: GHS02;GHS07;GHS08;GHS09 Danger
• Risk Statements: H226-H304-H315-H319-H332-H335-H400-H410
• Safety Statements: P210-P233-P240-P241-P242-P243-P261-P264-P264+P265-P271-P273-P280-P301+P316-P302+P352-P303+P361+P353-P304+P340-P305+P351+P338-P317-P319-P321-P331-P332+P317-P337+P317-P362+P364-P370+P378-P391-P403+P233-P403+P235-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Flammable liquids	Flam. Liq.	3	H226
Skin irritation	Skin Irrit.	2	H315
Eye irritation	Eye Irrit.	2	H319
Acute toxicity	Acute Tox.	4	H332
Aspiration hazard	Asp. Tox.	1	H304
Specific target organ toxicity - single exposure	STOT SE	3	H335
Chronic hazardous to the aquatic environment	Aquatic Chronic	2	H411
Acute hazardous to the aquatic environment	Aquatic Acute	1	H400
Chronic hazardous to the aquatic environment	Aquatic Chronic	1	H410
Chronic hazardous to the aquatic environment	Aquatic Chronic	3	H412
Specific target organ toxicity - single exposure	STOT SE	3	H336
Acute toxicity	Acute Tox.	4	H302
Germ cell mutagenicity	Muta.	2	H341
Specific target organ toxicity - repeated exposure	STOT RE	1	H372

Discovery and Applications

Methylstyrene, also known as vinyl toluene, is an aromatic hydrocarbon consisting of a benzene ring substituted with a methyl group and a vinyl group. It exists in three isomeric forms: ortho-, meta-, and para-methylstyrene, with the para-isomer (4-methylstyrene) being the most commonly encountered in commercial applications. The chemical formula for methylstyrene is C₉H₁₀.

Methylstyrene is typically obtained through the dehydrogenation of methyl-substituted ethylbenzenes or as a by-product in the production of styrene via ethylbenzene dehydrogenation. It can also be prepared by alkylating toluene with acetylene in the presence of a suitable catalyst under controlled conditions.

One of the primary uses of methylstyrene is as a monomer in polymer production. It undergoes free radical polymerization to form polymethylstyrene, a plastic material with properties similar to polystyrene but with slight variations in thermal and mechanical characteristics due to the methyl substitution. Copolymers of methylstyrene with other monomers, such as acrylonitrile, butadiene, or maleic anhydride, are also employed in the manufacture of resins, coatings, and adhesives.

In the coatings industry, methylstyrene-based polymers and copolymers are valued for their gloss, hardness, and resistance to water and chemicals. These materials are used in applications ranging from protective coatings for metals to finishes in consumer products.

Methylstyrene is also used as an intermediate in organic synthesis. Its vinyl group allows it to participate in various addition reactions, including crosslinking and functionalization processes in the synthesis of specialty chemicals. In this context, methylstyrene serves as a building block for compounds used in fragrances, pharmaceuticals, and agrochemicals.

Due to its volatile and flammable nature, methylstyrene is handled with appropriate safety measures. It is subject to industrial hygiene monitoring in workplaces where it is produced or used, and its environmental behavior is studied in relation to its volatility and potential for photochemical reactivity in the atmosphere.

Methylstyrene is a well-established compound in industrial and synthetic chemistry, known for its utility as a monomer, its reactivity in polymerization and chemical synthesis, and its role in producing durable and high-performance polymeric materials.

References

2019. Geminal Difunctionalization of Vinylarenes: Concise Synthesis of 1,3-Dioxolan-4-ones. Synlett, 30(18).
DOI: 10.1055/s-0039-1690250

2022. Applications of Photoredox Catalysis for the Radical-Induced Cleavage of C-C Bonds. Synthesis, 54(4).
DOI: 10.1055/a-1702-6193

2020. Chitosan supported molybdate nanoclusters as an efficient catalyst for oxidation of alkenes and alcohols. Cellulose, 27(14).
DOI: 10.1007/s10570-020-03368-3