Dimethyl terephthalate

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Dimethyl terephthalate
Structural formula of dimethyl terephthalate Dimethylterephthalat.svg
Structural formula of dimethyl terephthalate
Names
Preferred IUPAC name
Dimethyl benzene-1,4-dicarboxylate
Other names
  • Dimethyl terephthalate
  • 1,4-Benzenedicarboxylic acid dimethyl ester
  • Dimethyl 4-phthalate
  • Dimethyl p-phthalate
  • Di-Me terephthalate
  • Methyl 4-carbomethoxybenzoate
  • Methyl-p-(methoxycarbonyl)benzoate
  • Methyl terephthalate, di-
  • Terephthalic acid dimethyl ester (2:1)
Identifiers
3D model (JSmol)
AbbreviationsDMT
1107185
ChEBI
ChemSpider
ECHA InfoCard 100.004.011 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 204-411-8
MeSH Dimethyl+4-phthalate
PubChem CID
  • 8441
  • 12241382  (2H4)
RTECS number
  • WZ1225000
UNII
  • InChI=1S/C10H10O4/c1-13-9(11)7-3-5-8(6-4-7)10(12)14-2/h3-6H,1-2H3 Yes check.svgY
    Key: WOZVHXUHUFLZGK-UHFFFAOYSA-N Yes check.svgY
  • InChI=1/C10H10O4/c1-13-9(11)7-3-5-8(6-4-7)10(12)14-2/h3-6H,1-2H3
    Key: WOZVHXUHUFLZGK-UHFFFAOYSA-N
  • COC(=O)C1=CC=C(C=C1)C(=O)OC
  • O=C(OC)c1ccc(cc1)C(=O)OC
Properties
C10H10O4
Molar mass 194.186 g·mol−1
Appearancewhite 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 otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Dimethyl terephthalate (DMT) is an organic compound with the formula C6H4(COOCH3)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

Dimethyl terephthalate (DMT) has been produced in a number of ways.

From terephthalic acid by direct esterification

DMT can be prepared via a direct esterification of terephthalic acid with methanol:

C8H6O4 + 2 CH3OH → C10H10O4 + 2 H2O
Esterification of terephthalic acid with methanol.svg

On a commercial scale, this reaction is usually done at 250–300 °C (482–572 °F) using o-xylene as a solvent. The dimethyl terephthalate that is formed is then purified by distillation. Even terephthalic acid of low purity may be used in this method.

From p-xylene via partial oxidation and esterification

Alternatively, it can be prepared from para-xylene by alternating oxidation and methyl-esterification steps via methyl para-toluate (PT). [1]

Structure of monomethyl terephthalate Monomethyl terephthalate.png
Structure of monomethyl terephthalate

Uses

DMT is used in the production of polyesters, including polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), and polybutylene terephthalate (PBT). [2] Structurally, DMT consists of a benzene ring substituted at the 1 and 4 positions with methyl carboxylate (−CO2CH3) groups. Because DMT is volatile (boiling temperature of 141 °C), [3] it is an intermediate in some schemes for the recycling of PET, e.g. from plastic bottles. [4]

Hydrogenation of DMT affords the diol cyclohexanedimethanol, which is a useful monomer. [5]

Hazards

DMT is not directly dangerous to humans, but it is harmful to aquatic organisms, so environmental releases are avoided. It is flammable and the dust may form explosive mixtures with air. [6]

References

  1. 1 2 J. Sheehan, Richard. "Terephthalic Acid, Dimethyl Terephthalate, and Isophthalic Acid". Ullmann's Encyclopedia of Industrial Chemistry . Weinheim: Wiley-VCH. doi:10.1002/14356007.a26_193. ISBN   978-3-527-30673-2.
  2. ↑ PubChem. "Dimethyl terephthalate". pubchem.ncbi.nlm.nih.gov. Retrieved 2025-11-07.
  3. ↑ Elliott, John H.; Chris, Marjorie D. (1968-10-01). "Thermodynamic properties of high-purity dimethyl terephthalate". Journal of Chemical & Engineering Data. 13 (4): 475–479. doi:10.1021/je60039a005. ISSN   0021-9568.
  4. ↑ Zhang, Hui; Xia, Qing; Yang, Ying; Zhang, Feng-Bao; Zhang, Guo-Liang (2013-04-10). "Solubility of Dimethyl Terephthalate and Monomethyl Terephthalate in the Methanol Aqueous Solution and Its Application To Recycle Monomethyl Terephthalate from Crude Dimethyl Terephthalate". Industrial & Engineering Chemistry Research. 52 (14): 5230–5234. doi:10.1021/ie400421e. ISSN   0888-5885.
  5. ↑ Baikerikar, Kiran K.; Tulchinsky, Michael L.; Argyropoulos, John (March 2010). "UV curable, liquid diacrylate monomers based on (cis,trans)-1,3/1,4-cyclohexanedimethanol". Journal of Coatings Technology and Research. 7 (2): 175–188. doi:10.1007/s11998-009-9185-1. ISSN   1547-0091.
  6. ↑ International Chemical Safety Card 0262
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