Dimethyl terephthalate

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Dimethyl terephthalate
Structural formula of dimethyl terephthalate
Identifiers
Abbreviations DMT
CAS number 120-61-6 YesY
PubChem 8441, 12241382 (2H4)
ChemSpider 13863300 YesY
EC number 204-411-8
MeSH Dimethyl+4-phthalate
RTECS number WZ1225000
Beilstein Reference 1107185
Jmol-3D images Image 1
Image 2
Properties
Molecular formula C10H10O4
Molar mass 194.18 g mol−1
Appearance white solid
Density 1.2 g/cm³, ?
Melting point 142 °C (288 °F; 415 K)
Boiling point 288 °C (550 °F; 561 K)
Acidity (pKa) -7.21
Basicity (pKb) -6.60
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

Dimethyl terephthalate (DMT) is an organic compound with the formula C6H4(CO2CH3)2. It is the diester formed from terephthalic acid and methanol. It is a white solid that melts to give a distillable colourless liquid.[1]

Production[edit]

DMT has been produced in a number of ways. Conventionally and still of commercial value is the direct esterification of terephthalic acid. Alternatively, it can be prepared by alternating oxidation and methyl-esterification steps from p-xylene via methylp-toluate.[1]

Use[edit]

DMT is used in the production of polyesters, including polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), and polybutylene terephthalate (PBT). It consists of benzene substituted with carboxymethyl groups (CO2CH3) at the 1 and 4 positions. Because DMT is volatile, it is an intermediate in some schemes for the recycling of PET, e.g. from plastic bottles.

Hydrogenation of DMT affords the diol cyclohexanedimethanol, which is a useful monomer.

References[edit]

  1. ^ a b Richard J. Sheehan "Terephthalic Acid, Dimethyl Terephthalate, and Isophthalic Acid" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005.doi:10.1002/14356007.a26_193

External links[edit]