Methyl methacrylate

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Not to be confused with methyl acrylate. Methyl methacrylate_sentence_0

Methyl methacrylate_table_infobox_0

Methyl methacrylateMethyl methacrylate_table_caption_0
NamesMethyl methacrylate_header_cell_0_0_0
IdentifiersMethyl methacrylate_header_cell_0_1_0
CAS NumberMethyl methacrylate_cell_0_2_0 Methyl methacrylate_cell_0_2_1
3D model (JSmol)Methyl methacrylate_cell_0_3_0 Methyl methacrylate_cell_0_3_1
Beilstein ReferenceMethyl methacrylate_cell_0_4_0 605459Methyl methacrylate_cell_0_4_1
ChEBIMethyl methacrylate_cell_0_5_0 Methyl methacrylate_cell_0_5_1
ChEMBLMethyl methacrylate_cell_0_6_0 Methyl methacrylate_cell_0_6_1
ChemSpiderMethyl methacrylate_cell_0_7_0 Methyl methacrylate_cell_0_7_1
ECHA InfoCardMethyl methacrylate_cell_0_8_0 Q382897#P2566Methyl methacrylate_cell_0_8_1
EC NumberMethyl methacrylate_cell_0_9_0 Methyl methacrylate_cell_0_9_1
Gmelin ReferenceMethyl methacrylate_cell_0_10_0 2691Methyl methacrylate_cell_0_10_1
KEGGMethyl methacrylate_cell_0_11_0 Methyl methacrylate_cell_0_11_1
PubChem CIDMethyl methacrylate_cell_0_12_0 Methyl methacrylate_cell_0_12_1
RTECS numberMethyl methacrylate_cell_0_13_0 Methyl methacrylate_cell_0_13_1
UNIIMethyl methacrylate_cell_0_14_0 Methyl methacrylate_cell_0_14_1
UN numberMethyl methacrylate_cell_0_15_0 1247Methyl methacrylate_cell_0_15_1
CompTox Dashboard (EPA)Methyl methacrylate_cell_0_16_0 Methyl methacrylate_cell_0_16_1
PropertiesMethyl methacrylate_header_cell_0_17_0
Chemical formulaMethyl methacrylate_cell_0_18_0 C5H8O2Methyl methacrylate_cell_0_18_1
Molar massMethyl methacrylate_cell_0_19_0 100.117 g·molMethyl methacrylate_cell_0_19_1
AppearanceMethyl methacrylate_cell_0_20_0 Colorless liquidMethyl methacrylate_cell_0_20_1
OdorMethyl methacrylate_cell_0_21_0 acrid, fruityMethyl methacrylate_cell_0_21_1
DensityMethyl methacrylate_cell_0_22_0 0.94 g/cmMethyl methacrylate_cell_0_22_1
Melting pointMethyl methacrylate_cell_0_23_0 −48 °C (−54 °F; 225 K)Methyl methacrylate_cell_0_23_1
Boiling pointMethyl methacrylate_cell_0_24_0 101 °C (214 °F; 374 K)Methyl methacrylate_cell_0_24_1
Solubility in waterMethyl methacrylate_cell_0_25_0 1.5 g/100 mlMethyl methacrylate_cell_0_25_1
log PMethyl methacrylate_cell_0_26_0 1.35Methyl methacrylate_cell_0_26_1
Vapor pressureMethyl methacrylate_cell_0_27_0 29 mmHg (20°C)Methyl methacrylate_cell_0_27_1
Magnetic susceptibility (χ)Methyl methacrylate_cell_0_28_0 -57.3·10 cm/molMethyl methacrylate_cell_0_28_1
ViscosityMethyl methacrylate_cell_0_29_0 0.6 cP at 20 °CMethyl methacrylate_cell_0_29_1
StructureMethyl methacrylate_header_cell_0_30_0
Dipole momentMethyl methacrylate_cell_0_31_0 1.6–1.97 DMethyl methacrylate_cell_0_31_1
HazardsMethyl methacrylate_header_cell_0_32_0
Main hazardsMethyl methacrylate_cell_0_33_0 FlammableMethyl methacrylate_cell_0_33_1
Safety data sheetMethyl methacrylate_cell_0_34_0 See: data pageMethyl methacrylate_cell_0_34_1
GHS pictogramsMethyl methacrylate_cell_0_35_0 Methyl methacrylate_cell_0_35_1
GHS Signal wordMethyl methacrylate_cell_0_36_0 DangerMethyl methacrylate_cell_0_36_1
GHS hazard statementsMethyl methacrylate_cell_0_37_0 H225, H315, H317, H335Methyl methacrylate_cell_0_37_1
GHS precautionary statementsMethyl methacrylate_cell_0_38_0 P210, P233, P240, P241, P242, P243, P261, P264, P271, P272, P280, P302+352, P303+361+353, P304+340, P312, P321, P332+313, P333+313, P362, P363, P370+378, P403+233, P403+235, P405, P501Methyl methacrylate_cell_0_38_1
Flash pointMethyl methacrylate_cell_0_39_0 2 °C (36 °F; 275 K)Methyl methacrylate_cell_0_39_1
Autoignition temperatureMethyl methacrylate_cell_0_40_0 435 °C (815 °F; 708 K)Methyl methacrylate_cell_0_40_1
Explosive limitsMethyl methacrylate_cell_0_41_0 1.7%-8.2%Methyl methacrylate_cell_0_41_1
LC50 (median concentration)Methyl methacrylate_cell_0_42_0 18750 ppm (rat, 4 hr)

4447 ppm (mouse, 2 hr) 3750 ppm (rat) 4808 ppm (mammal)Methyl methacrylate_cell_0_42_1

LCLo (lowest published)Methyl methacrylate_cell_0_43_0 4400 ppm (rat, 8 hr)

4400 ppm (rabbit, 8 hr) 4207 ppm (rabbit, 4.5 hr) 4567 ppm (guinea pig, 5 hr)Methyl methacrylate_cell_0_43_1

PEL (Permissible)Methyl methacrylate_cell_0_44_0 TWA 100 ppm (410 mg/m)Methyl methacrylate_cell_0_44_1
REL (Recommended)Methyl methacrylate_cell_0_45_0 TWA 100 ppm (410 mg/m)Methyl methacrylate_cell_0_45_1
IDLH (Immediate danger)Methyl methacrylate_cell_0_46_0 1000 ppmMethyl methacrylate_cell_0_46_1
Supplementary data pageMethyl methacrylate_header_cell_0_47_0
Structure and propertiesMethyl methacrylate_cell_0_48_0 Refractive index (n),

Dielectric constant (εr), etc.Methyl methacrylate_cell_0_48_1

Thermodynamic

dataMethyl methacrylate_cell_0_49_0

Phase behaviour

solid–liquid–gasMethyl methacrylate_cell_0_49_1

Spectral dataMethyl methacrylate_cell_0_50_0 UV, IR, NMR, MSMethyl methacrylate_cell_0_50_1
Methyl methacrylate_cell_0_51_0 Methyl methacrylate_cell_0_51_1

Methyl methacrylate (MMA) is an organic compound with the formula CH2=C(CH3)COOCH3. Methyl methacrylate_sentence_1

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). Methyl methacrylate_sentence_2

Production and properties Methyl methacrylate_section_0

Given the scale of production, many methods have been developed starting from diverse two- to four-carbon precursors. Methyl methacrylate_sentence_3

Two principal routes appear to be commonly practiced. Methyl methacrylate_sentence_4

Cyanohydrin route Methyl methacrylate_section_1

The compound is manufactured by several methods, the principal one being the acetone cyanohydrin (ACH) route. Methyl methacrylate_sentence_5

ACH is produced by condensation of acetone and hydrogen cyanide. Methyl methacrylate_sentence_6

The cyanohydrin is hydrolyzed in the presence of sulfuric acid to a sulfate ester of the methacrylamide, Methanolysis of this ester gives ammonium bisulfate and MMA. Methyl methacrylate_sentence_7

Although widely used, the ACH route coproduces substantial amounts of ammonium sulfate. Methyl methacrylate_sentence_8

Methyl methacrylate_description_list_0

  • (CH3)2CO + HCN → (CH3)2C(OH)CNMethyl methacrylate_item_0_0
  • (CH3)2C(OH)CN + H2SO4 → (CH3)2C(OSO3H)C(O)NH2Methyl methacrylate_item_0_1

In fact the sulfate ester of the amide is initially produced as an adduct with sulfuric acid ((CH3)2C(OSO3H)C(O)NH2 H2SO4), which is removed in a cracking step. Methyl methacrylate_sentence_9

The sulfate ester is then methanolyzed (reacted with methanol): Methyl methacrylate_sentence_10

Methyl methacrylate_description_list_1

  • (CH3)2C(OSO3H)C(O)NH2 + CH3OH → CH2 =C(CH3)C(O)OCH3 + NH4HSO4Methyl methacrylate_item_1_2

As indicated in the last reaction, each kilogram of methyl methacrylate produced yields roughly 1.1 kg of ammonium hydrogen sulfate. Methyl methacrylate_sentence_11

Disposal of this salt is energy intensive. Methyl methacrylate_sentence_12

This technology affords more than 3 billion kilograms per year. Methyl methacrylate_sentence_13

The economics of the ACH route have been heavily optimized. Methyl methacrylate_sentence_14

Methyl propionate routes Methyl methacrylate_section_2

The first stage involves carboalkoxylation of ethylene to produce methyl propionate (MeP): Methyl methacrylate_sentence_15

Methyl methacrylate_description_list_2

  • C2H4 + CO + CH3OH → CH3CH2CO2CH3Methyl methacrylate_item_2_3

The MeP synthesis is conducted in a continuous-stirred tank reactor at moderate temperature and pressure using proprietary agitation and gas-liquid mixing arrangement. Methyl methacrylate_sentence_16

In a second set of reactions, MeP is condensed with formaldehyde in a single heterogeneous reaction step to form MMA: Methyl methacrylate_sentence_17

Methyl methacrylate_description_list_3

  • CH3CH2CO2CH3 + CH2O → CH3(CH2)CCO2CH3 + H2OMethyl methacrylate_item_3_4

The reaction of MeP and formaldehyde takes place over a fixed bed of catalyst. Methyl methacrylate_sentence_18

This catalyst, caesium oxide on silica, achieves good selectivity to MMA from MeP. Methyl methacrylate_sentence_19

The formation of a small amount of heavy, relatively involatile compounds poisons the catalyst. Methyl methacrylate_sentence_20

The coke is easily removed and catalyst activity and selectivity restored by controlled, in-situ regeneration. Methyl methacrylate_sentence_21

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. Methyl methacrylate_sentence_22

Unreacted MeP and water are recycled via the formaldehyde dehydration process. Methyl methacrylate_sentence_23

MMA (>99.9%) is purified by vacuum distillations. Methyl methacrylate_sentence_24

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. Methyl methacrylate_sentence_25

In 2008, Lucite International commissioned an Alpha MMA plant on Jurong Island in Singapore. Methyl methacrylate_sentence_26

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. Methyl methacrylate_sentence_27

Other routes to MMA Methyl methacrylate_section_3

Via propionaldehyde Methyl methacrylate_section_4

Ethylene is first hydroformylated to give propanal, which is then condensed with formaldehyde to produce methacrolein, The condensation is catalyzed by a secondary amine. Methyl methacrylate_sentence_28

Air oxidation of methacrolein to methacrylic acid completes the synthesis of the acid: Methyl methacrylate_sentence_29

Methyl methacrylate_description_list_4

  • CH3CH2CHO + HCHO → CH2=C(CH3)CHO + H2OMethyl methacrylate_item_4_5
  • CH2=C(CH3)CHO + ​⁄2 O2 → CH2=C(CH3)CO2HMethyl methacrylate_item_4_6

From isobutyric acid Methyl methacrylate_section_5

As developed by Atochem and Röhm, isobutyric acid is produced by hydrocarboxylation of propene, using HF as a catalyst: Methyl methacrylate_sentence_30

Methyl methacrylate_description_list_5

  • CH2=CHCH3 + CO + H2O → (CH3)2CHCO2HMethyl methacrylate_item_5_7

Oxidative dehydrogenation of the isobutyric acid yields methacrylic acid. Methyl methacrylate_sentence_31

Metal oxides catalyse this process: Methyl methacrylate_sentence_32

Methyl methacrylate_description_list_6

  • (CH3)2CHCO2H + O → CH2=C(CH3)CO2H + H2OMethyl methacrylate_item_6_8

Methyl acetylene (propyne) process Methyl methacrylate_section_6

Using Reppe chemistry, methyl acetylene is converted to MMA. Methyl methacrylate_sentence_33

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: Methyl methacrylate_sentence_34

Methyl methacrylate_description_list_7

  • CH≡CCH3 + CO + CH3OH → CH2=C(CH3)CO2CH3Methyl methacrylate_item_7_9

Isobutylene routes Methyl methacrylate_section_7

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. Methyl methacrylate_sentence_35

Methyl methacrylate_description_list_8

  • CH2=C(CH3)2 (or (CH3)3C–OH) + O2 → CH2=C(CH3)–CHO + H2OMethyl methacrylate_item_8_10

Methyl methacrylate_description_list_9

  • CH2=C(CH3)CHO + ​⁄2 O2 → CH2=C(CH3)CO2HMethyl methacrylate_item_9_11
  • CH2=C(CH3)CO2H + CH3OH → CH2=C(CH3)CO2CH3 + H2OMethyl methacrylate_item_9_12

A process using isobutylene as a raw material has been commercialized by Escambia Co. Isobutylene is oxidized to provide α-hydroxy isobutyric acid. Methyl methacrylate_sentence_36

The conversion uses N2O4 and nitric acid at 5–10 °C in the liquid phase. Methyl methacrylate_sentence_37

After esterification and dehydration MMA is obtained. Methyl methacrylate_sentence_38

Challenges with this route, aside from yield, involve the handling of large amounts of nitric acid and NOx. Methyl methacrylate_sentence_39

This method was discontinued in 1965 after an explosion at an operation plant. Methyl methacrylate_sentence_40

Methacrylonitrile (MAN) process Methyl methacrylate_section_8

MAN can be produced by ammoxidation from isobutylene: Methyl methacrylate_sentence_41

Methyl methacrylate_description_list_10

  • (CH3)2C=CH2 + NH3 + ​⁄2 O2 → CH2=C(CH3)CN + 3 H2OMethyl methacrylate_item_10_13

This step is analogous to the industrial route to acrylonitrile, a related commodity chemical. Methyl methacrylate_sentence_42

MAN can be hydrated by sulfuric acid to methacrylamide: Methyl methacrylate_sentence_43

Methyl methacrylate_description_list_11

  • CH2=C(CH3)CN + H2SO4 + H2O → CH2=C(CH3)–CONH2·H2SO4Methyl methacrylate_item_11_14
  • CH2=C(CH3)–CONH2·H2SO4 + CH3OH → CH2=C(CH3)COOCH3 + NH4HSO4Methyl methacrylate_item_11_15

Mitsubishi Gas Chemicals proposed that MAN can be hydrated to methacrylamide without using sulfuric acid and is then esterified to obtain MMA by methylformate. Methyl methacrylate_sentence_44

Methyl methacrylate_description_list_12

  • CH2=C(CH3)CN + H2O → CH2=C(CH3)–CONH2Methyl methacrylate_item_12_16
  • CH2=C(CH3)–CONH2 + HCOOCH3 → CH2=C(CH3)COOCH3 + HCONH2Methyl methacrylate_item_12_17
  • HCONH2 → NH3 + COMethyl methacrylate_item_12_18

Esterification of methacrolein Methyl methacrylate_section_9

Asahi Chemical developed a process based on direct oxidative esterification of methacrolein, which does not produce by-products such as ammonium bisulfate. Methyl methacrylate_sentence_45

The raw material is tert-butanol, as in the direct oxidation method. Methyl methacrylate_sentence_46

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. Methyl methacrylate_sentence_47

Methyl methacrylate_description_list_13

  • CH2=C(CH3)–CHO + CH3OH + ​⁄2 O2 → CH2=C(CH3)–COOCH3 + H2OMethyl methacrylate_item_13_19

Uses Methyl methacrylate_section_10

Main article: Acrylate polymers Methyl methacrylate_sentence_48

The principal application, consuming approximately 75% of the MMA, is the manufacture of polymethyl methacrylate acrylic plastics (PMMA). Methyl methacrylate_sentence_49

Methyl methacrylate is also used for the production of the co-polymer methyl methacrylate-butadiene-styrene (MBS), used as a modifier for PVC. Methyl methacrylate_sentence_50

Another application is as cement used in total hip replacements as well as total knee replacements. Methyl methacrylate_sentence_51

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. Methyl methacrylate_sentence_52

Typically the lifespan of methylmethacrylate as bone cement is 20 years before revision surgery is required. Methyl methacrylate_sentence_53

Cemented implants are usually only done in elderly populations that require more immediate short term replacements. Methyl methacrylate_sentence_54

In younger populations, cementless implants are used because their lifespan is considerably longer. Methyl methacrylate_sentence_55

Also used in fracture repair in small exotic animal species using internal fixation. Methyl methacrylate_sentence_56

MMA is a raw material for the manufacture of other methacrylates. Methyl methacrylate_sentence_57

These derivatives include ethyl methacrylate (EMA), butyl methacrylate (BMA) and 2-ethyl hexyl methacrylate (2-EHMA). Methyl methacrylate_sentence_58

Methacrylic acid (MAA) is used as a chemical intermediate as well as in the manufacture of coating polymers, construction chemicals and textile applications. Methyl methacrylate_sentence_59

Wood can be impregnated with MMA and polymerized in situ to produce a stabilized product. Methyl methacrylate_sentence_60

Environmental issues and health hazards Methyl methacrylate_section_11

In terms of the acute toxicity of methyl methacrylate, the LD50 is 7-10 g/kg (oral, rat). Methyl methacrylate_sentence_61

It is an irritant to the eyes and can cause redness and pain. Methyl methacrylate_sentence_62

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_sentence_63

Methyl methacrylate is a mild skin irritant in humans and has the potential to induce skin sensitization in susceptible individuals. Methyl methacrylate_sentence_64

See also Methyl methacrylate_section_12

Methyl methacrylate_unordered_list_14


Credits to the contents of this page go to the authors of the corresponding Wikipedia page: en.wikipedia.org/wiki/Methyl methacrylate.