Methyl methacrylate

Last updated
Methyl methacrylate
Methyl-methacrylate-skeletal.png
Methyl-methacrylate-3D-balls.png
Names
Preferred IUPAC name
Methyl 2-methylprop-2-enoate
Other names
Methyl 2-methylpropenoate
methyl methacrylate
MMA
2-(methoxycarbonyl)-1-propene
Identifiers
3D model (JSmol)
605459
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.001.180 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 201-297-1
2691
KEGG
PubChem CID
RTECS number
  • OZ5075000
UNII
UN number 1247
  • InChI=1S/C5H8O2/c1-4(2)5(6)7-3/h1H2,2-3H3 Yes check.svgY
    Key: VVQNEPGJFQJSBK-UHFFFAOYSA-N Yes check.svgY
  • O=C(OC)C(=C)C
Properties
C5H8O2
Molar mass 100.117 g·mol−1
AppearanceColorless liquid
Odor acrid, fruity [1]
Density 0.94 g/cm3
Melting point −48 °C (−54 °F; 225 K)
Boiling point 101 °C (214 °F; 374 K)
1.5 g/100 ml
log P 1.35 [2]
Vapor pressure 29 mmHg (20 °C) [1]
-57.3·10−6 cm3/mol
Viscosity 0.6 cP at 20 °C
Structure
1.6–1.97 D
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
Flammable
GHS labelling:
GHS-pictogram-flamme.svg GHS-pictogram-exclam.svg
Danger
H225, H315, H317, H335
P210, P233, P240, P241, P242, P243, P261, P264, P271, P272, P280, P302+P352, P303+P361+P353, P304+P340, P312, P321, P332+P313, P333+P313, P362, P363, P370+P378, P403+P233, P403+P235, P405, P501
NFPA 704 (fire diamond)
NFPA 704.svgHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 3: Liquids and solids that can be ignited under almost all ambient temperature conditions. Flash point between 23 and 38 °C (73 and 100 °F). E.g. gasolineInstability 2: Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water. E.g. white phosphorusSpecial hazards (white): no code
2
3
2
Flash point 2 °C (36 °F; 275 K)
435 °C (815 °F; 708 K)
Explosive limits 1.7%-8.2% [1]
Lethal dose or concentration (LD, LC):
8420-10000 mg/kg (rat, oral)
5000-7500 mg/kg (rabbit, dermal)
18750 ppm (rat, 4 hr)
4447 ppm (mouse, 2 hr)
3750 ppm (rat)
4808 ppm (mammal) [3]
4400 ppm (rat, 8 hr)
4400 ppm (rabbit, 8 hr)
4207 ppm (rabbit, 4.5 hr)
4567 ppm (guinea pig, 5 hr) [3]
NIOSH (US health exposure limits):
PEL (Permissible)
TWA 100 ppm (410 mg/m3) [1]
REL (Recommended)
TWA 100 ppm (410 mg/m3) [1]
IDLH (Immediate danger)
1000 ppm [1]
Safety data sheet (SDS) Methyl methacrylate MSDS
Supplementary data page
Methyl methacrylate (data page)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
X mark.svgN  verify  (what is  Yes check.svgYX mark.svgN ?)

Methyl methacrylate (MMA) is an organic compound with the formula CH2=C(CH3)COOCH3. This colorless liquid, the methyl ester of methacrylic acid (MAA), is a monomer produced on a large scale for the production of poly(methyl methacrylate) (PMMA). [4]

Contents

History

MMA was discovered by Bernhard Tollens and his student W. A. Caspary in 1873, [5] who noticed and described its tendency to change into a clear, hard, transparent substance especially in sunlight. [6] Studies on acrylic esters slowly developed until the Staudinger's theory of macromolecules and his research into the nature of polyacrylates allowed to control the polymerization. Company Rohm and Haas founded by German chemist Otto Röhm, who investigated the topic for three decades, was finally able to start its industrial production in 1931. [7]

Production and properties

Given the scale of production, many methods have been developed starting from diverse two- to four-carbon precursors. [8] Two principal routes appear to be commonly practiced.

Cyanohydrin route

The principal route begins with the condensation of acetone and hydrogen cyanide: [4]

(CH3)2CO + HCN → (CH3)2C(OH)CN

Sulfuric acid then hydrolyzes acetone cyanohydrin (ACH) to a sulfate ester-adduct, which is cracked to the ester:

(CH3)2C(OH)CN + 2H2SO4 → ((CH3)2C(OSO3H)C(O)NH2·H2SO4 → (CH3)2C(OSO3H)C(O)NH2 + H2SO4

Methanolysis gives ammonium bisulfate and MMA:

(CH3)2C(OSO3H)C(O)NH2 + CH3OH → CH2=C(CH3)C(O)OCH3 + NH4HSO4

Laboratory scale procedures are available for some of these steps. [9]

This technology affords more than 3 billion kilograms per year, and the economics have been optimized. [10] [11] Nevertheless, the ACH route coproduces substantial amounts of ammonium sulfate: roughly 1.1 kg/(kg MMA). The ammonium sulfate can be converted to diammonium sulfate, which is a common fertilizer. Also it can be combusted to give sulfuric acid.

Methyl propionate routes

The first stage involves carboalkoxylation of ethylene to produce methyl propionate (MeP): [12]

C2H4 + CO + CH3OH → CH3CH2CO2CH3

The MeP synthesis is conducted in a continuous-stirred tank reactor at moderate temperature and pressure using proprietary agitation and gas-liquid mixing arrangement.

In a second set of reactions, MeP is condensed with formaldehyde in a single heterogeneous reaction step to form MMA: [13]

CH3CH2CO2CH3 + CH2O → CH3(CH2)CCO2CH3 + H2O

The reaction of MeP and formaldehyde takes place over a fixed bed of catalyst. This catalyst, caesium oxide on silica, achieves good selectivity to MMA from MeP. The formation of a small amount of heavy, relatively involatile compounds poisons the catalyst. The coke is easily removed and catalyst activity and selectivity restored by controlled, in-situ regeneration. The reactor product stream is separated in a primary distillation so that a crude MMA product stream, free from water, MeP and formaldehyde, is produced. Unreacted MeP and water are recycled via the formaldehyde dehydration process. MMA (>99.9%) is purified by vacuum distillations. The separated streams are returned to the process; there being only a small heavy ester purge stream, which is disposed of in a thermal oxidizer with heat recovered for use in the process.

In 2008, Lucite International commissioned an Alpha MMA plant on Jurong Island in Singapore. This process plant was cheaper to build and run than conventional systems, produces virtually no waste and the feedstocks can even be made from biomass.

Other routes to MMA

Via propionaldehyde

Ethylene is first hydroformylated to give propanal, which is then condensed with formaldehyde to produce methacrolein, The condensation is catalyzed by a secondary amine. Air oxidation of methacrolein to methacrylic acid completes the synthesis of the acid: [10]

CH3CH2CHO + HCHO → CH2=C(CH3)CHO + H2O
CH2=C(CH3)CHO + ½ O2 → CH2=C(CH3)CO2H

From isobutyric acid

As developed by Atochem and Röhm, isobutyric acid is produced by hydrocarboxylation of propene, using HF as a catalyst:

CH2=CHCH3 + CO + H2O → (CH3)2CHCO2H

Oxidative dehydrogenation of the isobutyric acid yields methacrylic acid. Metal oxides catalyse this process: [10]

(CH3)2CHCO2H + O → CH2=C(CH3)CO2H + H2O

Methyl acetylene (propyne) process

Using Reppe chemistry, methyl acetylene is converted to MMA. As developed by Shell, this process produces MMA in one step reaction with 99% yield with a catalyst derived from palladium acetate, phosphine ligands, and Bronsted acids as catalyst: [10]

CH≡CCH3 + CO + CH3OH → CH2=C(CH3)CO2CH3

Isobutylene routes

The reactions by the direct oxidation method consist of two-step oxidation of isobutylene or TBA with air to produce methacrylic acid and esterification by methanol to produce MMA. [10]

CH2=C(CH3)2
or (CH3)3C−OH + O2 → CH2=C(CH3)−CHO + H2O
CH2=C(CH3)CHO + ½ O2 → CH2=C(CH3)CO2H
CH2=C(CH3)CO2H + CH3OH → CH2=C(CH3)CO2CH3 + H2O

A process using isobutylene as a raw material has been commercialized by Escambia Co. Isobutylene is oxidized to provide α-hydroxy isobutyric acid. The conversion uses N2O4 and nitric acid at 5–10 °C in the liquid phase. After esterification and dehydration MMA is obtained. Challenges with this route, aside from yield, involve the handling of large amounts of nitric acid and NOx. This method was discontinued in 1965 after an explosion at an operation plant. [10]

Methacrylonitrile (MAN) process

MAN can be produced by ammoxidation from isobutylene:

(CH3)2C=CH2 + NH3 + 3/2 O2 → CH2=C(CH3)CN + 3 H2O

This step is analogous to the industrial route to acrylonitrile, a related commodity chemical. MAN can be hydrated by sulfuric acid to methacrylamide:

CH2=C(CH3)CN + H2SO4 + H2O → CH2=C(CH3)−CONH2·H2SO4
CH2=C(CH3)−CONH2·H2SO4 + CH3OH → CH2=C(CH3)COOCH3 + NH4HSO4

Mitsubishi Gas Chemicals proposed that MAN can be hydrated to methacrylamide without using sulfuric acid and is then esterified to obtain MMA by methylformate. [10]

CH2=C(CH3)CN + H2O → CH2=C(CH3)−CONH2
CH2=C(CH3)−CONH2 + HCOOCH3 → CH2=C(CH3)COOCH3 + HCONH2
HCONH2 → NH3 + CO

Esterification of methacrolein

Asahi Chemical developed a process based on direct oxidative esterification of methacrolein, which does not produce by-products such as ammonium bisulfate. The raw material is tert-butanol, as in the direct oxidation method. In the first step, methacrolein is produced in the same way as in the direct oxidation process by gas phase catalytic oxidation, is simultaneously oxidized and is esterified in liquid methanol to get MMA directly. [10]

CH2=C(CH3)−CHO + CH3OH + ½ O2 → CH2=C(CH3)−COOCH3 + H2O

Uses

The principal application, consuming approximately 75% of the MMA, is the manufacture of polymethyl methacrylate acrylic plastics (PMMA). Methyl methacrylate is also used for the production of the co-polymer methyl methacrylate-butadiene-styrene (MBS), used as a modifier for PVC. Another application is as cement used in total hip replacements as well as total knee replacements. Used as the "grout" by orthopedic surgeons to make the bone inserts fix into bone, it greatly reduces post-operative pain from the insertions but has a finite lifespan. Typically the lifespan of methylmethacrylate as bone cement is 20 years before revision surgery is required. Cemented implants are usually only done in elderly populations that require more immediate short term replacements. In younger populations, cementless implants are used because their lifespan is considerably longer. [14] Also used in fracture repair in small exotic animal species using internal fixation.

MMA is a raw material for the manufacture of other methacrylates. These derivatives include ethyl methacrylate (EMA), butyl methacrylate (BMA) and 2-ethyl hexyl methacrylate (2-EHMA). Methacrylic acid (MAA) is used as a chemical intermediate as well as in the manufacture of coating polymers, construction chemicals and textile applications. [15]

Wood can be impregnated with MMA and polymerized in situ to produce stabilized wood .

Environmental issues and health hazards

In terms of the acute toxicity of methyl methacrylate, the LD50 is 7–10 g/kg (oral, rat). It is an irritant to the eyes and can cause redness and pain. [16] [17] Irritation of the skin, eye, and nasal cavity has been observed in rodents and rabbits exposed to relatively high concentrations of methyl methacrylate. Methyl methacrylate is a mild skin irritant in humans and has the potential to induce skin sensitization in susceptible individuals. [18] [19]

See also

Related Research Articles

<span class="mw-page-title-main">Carboxylic acid</span> Organic compound containing a –C(=O)OH group

In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group attached to an R-group. The general formula of a carboxylic acid is often written as R−COOH or R−CO2H, sometimes as R−C(O)OH with R referring to an organyl group, or hydrogen, or other groups. Carboxylic acids occur widely. Important examples include the amino acids and fatty acids. Deprotonation of a carboxylic acid gives a carboxylate anion.

<span class="mw-page-title-main">Ether</span> Organic compounds made of alkyl/aryl groups bound to oxygen (R–O–R)

In organic chemistry, ethers are a class of compounds that contain an ether group—an oxygen atom bonded to two organyl groups. They have the general formula R−O−R′, where R and R′ represent the organyl groups. Ethers can again be classified into two varieties: if the organyl groups are the same on both sides of the oxygen atom, then it is a simple or symmetrical ether, whereas if they are different, the ethers are called mixed or unsymmetrical ethers. A typical example of the first group is the solvent and anaesthetic diethyl ether, commonly referred to simply as "ether". Ethers are common in organic chemistry and even more prevalent in biochemistry, as they are common linkages in carbohydrates and lignin.

<span class="mw-page-title-main">Ester</span> Compound derived from an acid

In chemistry, an ester is a functional group derived from an acid in which the hydrogen atom (H) of at least one acidic hydroxyl group of that acid is replaced by an organyl group. Analogues derived from oxygen replaced by other chalcogens belong to the ester category as well. According to some authors, organyl derivatives of acidic hydrogen of other acids are esters as well, but not according to the IUPAC.

In chemistry, a hydration reaction is a chemical reaction in which a substance combines with water. In organic chemistry, water is added to an unsaturated substrate, which is usually an alkene or an alkyne. This type of reaction is employed industrially to produce ethanol, isopropanol, and butan-2-ol.

<span class="mw-page-title-main">Phthalic anhydride</span> Chemical compound

Phthalic anhydride is the organic compound with the formula C6H4(CO)2O. It is the anhydride of phthalic acid. Phthalic anhydride is a principal commercial form of phthalic acid. It was the first anhydride of a dicarboxylic acid to be used commercially. This white solid is an important industrial chemical, especially for the large-scale production of plasticizers for plastics. In 2000, the worldwide production volume was estimated to be about 3 million tonnes per year.

<span class="mw-page-title-main">Acrylic acid</span> Chemical compound

Acrylic acid (IUPAC: prop-2-enoic acid) is an organic compound with the formula CH2=CHCOOH. It is the simplest unsaturated carboxylic acid, consisting of a vinyl group connected directly to a carboxylic acid terminus. This colorless liquid has a characteristic acrid or tart smell. It is miscible with water, alcohols, ethers, and chloroform. More than a million tons are produced annually.

<span class="mw-page-title-main">Isobutyric acid</span> Carboxylic acid with chemical formula (CH3)2CHCO2H

Isobutyric acid, also known as 2-methylpropanoic acid or isobutanoic acid, is a carboxylic acid with structural formula (CH3)2CHCOOH. It is an isomer of butyric acid. It is classified as a short-chain fatty acid. Deprotonation or esterification gives derivatives called isobutyrates.

<span class="mw-page-title-main">Methyl formate</span> Chemical compound

Methyl formate, also called methyl methanoate, is the methyl ester of formic acid. The simplest example of a carboxylate ester, it is a colorless liquid with an ethereal odour, high vapor pressure, and low surface tension. It is a precursor to many other compounds of commercial interest.

<span class="mw-page-title-main">Methylamine</span> Organic chemical compound

Methylamine is an organic compound with a formula of CH3NH2. This colorless gas is a derivative of ammonia, but with one hydrogen atom being replaced by a methyl group. It is the simplest primary amine.

<span class="mw-page-title-main">Isobutylene</span> Unsaturated hydrocarbon compound (H2C=C(CH3)2)

Isobutylene is a hydrocarbon with the chemical formula (CH3)2C=CH2. It is a four-carbon branched alkene (olefin), one of the four isomers of butylene. It is a colorless flammable gas, and is of considerable industrial value.

<span class="mw-page-title-main">Acetone</span> Organic compound ((CH3)2CO); simplest ketone

Acetone is an organic compound with the formula (CH3)2CO. It is the simplest and smallest ketone. It is a colorless, highly volatile, and flammable liquid with a characteristic pungent odour, very reminiscent of the smell of pear drops.

<span class="mw-page-title-main">Dimethylamine</span> Chemical compound

Dimethylamine is an organic compound with the formula (CH3)2NH. This secondary amine is a colorless, flammable gas with an ammonia-like odor. Dimethylamine is commonly encountered commercially as a solution in water at concentrations up to around 40%. An estimated 270,000 tons were produced in 2005.

<span class="mw-page-title-main">Isobutanol</span> Chemical compound

Isobutanol (IUPAC nomenclature: 2-methylpropan-1-ol) is an organic compound with the formula (CH3)2CHCH2OH (sometimes represented as i-BuOH). This colorless, flammable liquid with a characteristic smell is mainly used as a solvent either directly or as its esters. Its isomers are 1-butanol, 2-butanol, and tert-butanol, all of which are important industrially.

<span class="mw-page-title-main">Methacrylic acid</span> Chemical compound

Methacrylic acid, abbreviated MAA, is an organic compound with the formula CH2=C(CH3)CO2H. This colorless, viscous liquid is a carboxylic acid with an acrid unpleasant odor. It is soluble in warm water and miscible with most organic solvents. Methacrylic acid is produced industrially on a large scale as a precursor to its esters, especially methyl methacrylate (MMA), and to poly(methyl methacrylate) (PMMA).

<span class="mw-page-title-main">Methyl bisulfate</span> Chemical compound

Methyl bisulfate is a chemical compound with the molecular formula (CH3)HSO4. This compound is the mono-methyl ester of sulfuric acid. Its structure is CH3−O−S(=O)2−OH. The significance of methyl bisulfate is that it is an intermediate in the hydrolysis of the important reagent dimethyl sulfate, (CH3)2SO4:

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References

  1. 1 2 3 4 5 6 NIOSH Pocket Guide to Chemical Hazards. "#0426". National Institute for Occupational Safety and Health (NIOSH).
  2. ↑ "Methyl methacrylate". Chemsrc.com. Retrieved 30 November 2021.
  3. 1 2 "Methyl methacrylate". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  4. 1 2 Bauer, Jr., William (2002). "Methacrylic Acid and Derivatives". Ullmann's Encyclopedia of Industrial Chemistry . Weinheim: Wiley-VCH. doi:10.1002/14356007.a16_441. ISBN   978-3527306732.
  5. ↑ Caspary, W.; Tollens, B. (January 1873). "Ueberführung der β-Bibrompropionsäure in Acrylsäure". Justus Liebigs Annalen der Chemie. 167 (2): 240–257. doi:10.1002/jlac.18731670208. ISSN   0075-4617.
  6. ↑ "New series: Acrylic patented 90 years ago". www.k-online.com. Retrieved 2024-02-27.
  7. ↑ Neher, Harry T. (March 1936). "Acrylic Resins". Industrial & Engineering Chemistry. 28 (3): 267–271. doi:10.1021/ie50315a002. ISSN   0019-7866.
  8. ↑ Darabi Mahboub, Mohammad Jaber; Dubois, Jean-Luc; Cavani, Fabrizio; Rostamizadeh, Mohammad; Patience, Gregory S. (2018). "Catalysis for the synthesis of methacrylic acid and methyl methacrylate". Chemical Society Reviews. 47 (20): 7703–7738. doi:10.1039/C8CS00117K. PMID   30211916.
  9. ↑ Wiley, Richard H.; Waddey, Walter E. (1949). "Methacrylamide". Organic Syntheses. 29: 61. doi:10.15227/orgsyn.029.0061.
  10. 1 2 3 4 5 6 7 8 Nagai, Koichi (2001). "New developments in the production of methyl methacrylate". Applied Catalysis A: General. 221 (1–2): 367–377. doi:10.1016/S0926-860X(01)00810-9.
  11. ↑ "New Catalyst for Methyl Methacrylate Process :: News". Chemistryviews.org. 22 August 2012.
  12. ↑ Scott D. Barnicki (2012). "Chapter 10. Synthetic Organic Chemicals". In James A. Kent (ed.). Handbook of Industrial Chemistry and Biotechnology (12th ed.). New York: Springer. ISBN   978-1-4614-4259-2.
  13. ↑ "Archived copy" (PDF). Archived from the original (PDF) on 2015-09-24. Retrieved 2013-10-29.{{cite web}}: CS1 maint: archived copy as title (link)
  14. ↑ Nordin, Margareta (2001). Basic Biomechanics of the Musculoskeletal System. New York: Lippincott Williams & Wilkins. pp. 401–419. ISBN   978-0-683-30247-9.
  15. ↑ "Mpausa - Methacrylates & Why They Are Important". Mpausa.org.
  16. ↑ "Methyl methacrylate". NIOSH Pocket Guide to Chemical Hazards. Centers for Disease Control and Prevention . Retrieved 2020-01-26.
  17. ↑ "ICSC 0300 - Methyl methacrylate". International Chemical Safety Cards . UN International Labour Organization and World Health Organization.
  18. ↑ "Concise International Chemical Assessment Document 4 : METHYL METHACRYLATE" (PDF). Who.int. Retrieved 2021-11-30.
  19. ↑ "Archived copy" (PDF). Archived from the original (PDF) on 2013-01-24. Retrieved 2013-10-29.{{cite web}}: CS1 maint: archived copy as title (link)
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