Methyl methacrylate

August 27, 2018
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Methyl methacrylate (MMA) is an unsaturated ester that has several uses in polymer manufacturing. It is a clear liquid with a characteristic ester odor.

There are several synthetic routes to MMA. The most widely used are a three-step sequence that begins with acetone and HCN and proceeds through acetone cyanohydrin; and a two-step process that begins with the reaction of ethylene and methanol to produce methyl propionate.

By far the greatest volume of MMA is polymerized to the homopolymer poly(methyl methacrylate) (PMMA). The polymer is a clear plastic that is known by the familiar trade names Lucite and Plexiglas.

MMA is also copolymerized with styrene and butadiene to make an additive to poly(vinyl chloride) (PVC) that improves its properties. MMA is also transesterified to make specialty methacrylate monomers.

Methyl methacrylate hazard information

GHS classification*: flammable liquids, category 2
H225—Highly flammable liquid and vaporChemical Safety Warning
GHS classification: skin irritation, category 2
H315—Causes skin irritationChemical Safety Warning
GHS classification: skin sensitization, category 1
H317—May cause an allergic skin reactionChemical Safety Warning
GHS classification: specific target organ toxicity, single exposure; respiratory tract irritation, category 3
H335—May cause respiratory irritationChemical Safety Warning
GHS classification: hazardous to the aquatic environment, acute hazard, category 3

*Globally Harmonized System of Classification and Labeling of Chemicals. Explanation of pictograms.

Methyl methacrylate
fast facts

CAS Reg. No.


Molar mass100.12 g/mol
Empirical formulaC5H8O2
AppearanceColorless liquid
Boiling point

101 ºC

Water solubility15 g/L

MOTW update:
April 3, 2023

Methyl methacrylate1 (MMA) is an unsaturated ester that is used to make polymers that range from water-based latexes to clear plastics.

On March 24, 2023, MMA and two other latex monomers, butyl acrylate2 and ethyl acrylate3, were released into the Delaware River during a discharge from a polymer manufacturing plant in Bristol, PA. All three monomers are respiratory and dermal hazards. On March 26, authorities stated that the tap water in Philadelphia and surrounding southeastern Pennsylvania communities was safe to drink; but they advised residents to use bottled drinking water. The result was panic buying that left store shelves empty. As of this writing, Philadelphia tap water has not been shown to be contaminated.

1. CAS Reg. No. 80-62-6.
2. CAS Reg. No. 141-32-2.
3. CAS Reg. No. 140-88-5.

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