Dimethyl terephthalate

Dimethyl terephthalate
Preferred IUPAC name

Dimethyl terephthalate
Systematic name

1,4-Dimethyl benzene-1,4-dicarboxylate
Other names

1,4-Benzenedicarboxylic acid dimethyl ester

Dimethyl 4-phthalate
Dimethyl-p-phthalate
Di-Me terephthalate
Methyl 4-carbomethoxybenzoate
Methyl-p-(methoxycarbonyl)benzoate
Methyl terephthalate

Terephthalic acid methyl ester
Identifiers
Abbreviations DMT
CAS number 120-61-6 Y
PubChem 8441, 12241382 (2H4)
ChemSpider 13863300 Y
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
Exact mass 198.083015792 g mol-1
Appearance white solid
Density 1.2 g/cm³, ?
Melting point

142 °C, 415 K, 288 °F
Boiling point

288 °C, 561 K, 550 °F
Acidity (pKa) -7.21
Basicity (pKb) -6.60
 Y (verify) (what is: Y/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
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]

Contents

Production

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

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

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

References

  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