2-Hydroxyethyl terephthalic acid

2-Hydroxyethyl terephthalic acid
Names
	Preferred IUPAC name 4-[(2-Hydroxyethoxy)carbonyl]benzoic acid
	Other names 1,4-Benzenedicarboxylic acid, 1-(2-hydroxyethyl) ester
Identifiers
CAS Number	1137-99-1 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:131735;
PubChem CID	174073;
UNII	8DN7KSY2WN ;
CompTox Dashboard (EPA)	DTXSID60622186 ;
	InChI InChI=1S/C10H10O5/c11-5-6-15-10(14)8-3-1-7(2-4-8)9(12)13/h1-4,11H,5-6H2,(H,12,13) Key: BCBHDSLDGBIFIX-UHFFFAOYSA-N;
	SMILES C1=CC(=CC=C1C(=O)O)C(=O)OCCO;
Properties
Chemical formula	C10H10O5
Molar mass	210.185 g·mol−1
Appearance	White solid
Melting point	183–186 °C (361–367 °F; 456–459 K)
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

2-Hydroxyethyl terephthalic acid is an organic compound with the formula HOC₂H₄O₂CC₆H₄CO₂H. It is the monoester of terephthalic acid and ethylene glycol. The compound is a precursor to poly(ethylene terephthalate) (PET), a polymer that is produced on a large scale industrially.^[1] 2-Hydroxyethyl terephthalic acid is a colorless solid that is soluble in water and polar organic solvents. Near neutral pH, 2-hydroxyethyl terephthalic acid converts to 2-hydroxyethyl terephthalate, HOC₂H₄O₂CC₆H₄CO₂⁻.

Occurrence and reactions

2-Hydroxyethyl terephthalic acid is an intermediate in both the formation and hydrolysis of PET. It is produced on a massive scale as the first intermediate in certain routes to PET. Specifically, it is produced in the course of the thermal condensation of terephthalic acid and ethylene glycol:

HOC₂H₄OH + HO₂CC₆H₄CO₂H → HOC₂H₄O₂CC₆H₄CO₂H + H₂O

Further dehydration of 2-hydroxyethyl terephthalic acid gives PET.

It is also produced by the partial hydrolysis of PET, as catalyzed by the enzyme PETase:^[2]

H[O₂CC₆H₄CO₂C₂H₄]_nOH + n H₂O → n HO₂CC₆H₄CO₂C₂H₄OH

References

^ Sheehan, Richard J. (June 15, 2000). "Terephthalic Acid, Dimethyl Terephthalate, and Isophthalic Acid". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a26_193. ISBN 978-3527306732.
^ Yoshida, Shosuke; Hiraga, Kazumi; Takehana, Toshihiko; Taniguchi, Ikuo; Yamaji, Hironao; Maeda, Yasuhito; Toyohara, Kiyotsuna; Miyamoto, Kenji; Kimura, Yoshiharu (2016-03-11). "A bacterium that degrades and assimilates poly(ethylene terephthalate)". Science. 351 (6278): 1196–1199. Bibcode:2016Sci...351.1196Y. doi:10.1126/science.aad6359. ISSN 0036-8075. PMID 26965627. S2CID 31146235.

[Ullmann-1] Sheehan, Richard J. (June 15, 2000). "Terephthalic Acid, Dimethyl Terephthalate, and Isophthalic Acid". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a26_193. ISBN 978-3527306732.

[Yoshida_2016-2] Yoshida, Shosuke; Hiraga, Kazumi; Takehana, Toshihiko; Taniguchi, Ikuo; Yamaji, Hironao; Maeda, Yasuhito; Toyohara, Kiyotsuna; Miyamoto, Kenji; Kimura, Yoshiharu (2016-03-11). "A bacterium that degrades and assimilates poly(ethylene terephthalate)". Science. 351 (6278): 1196–1199. Bibcode:2016Sci...351.1196Y. doi:10.1126/science.aad6359. ISSN 0036-8075. PMID 26965627. S2CID 31146235.

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[2]