T

Terephthalic acid

IUPAC: terephthalic acid

C8H6O4 Acids CAS 100-21-0
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Quick Reference
Formula / NotationC8H6O4
CAS Number100-21-0
Molecular Weight166.13
Melting PointSublimes (NTP, 1992)
Boiling Pointgreater than 572 °F at 760 mmHg (sublimes without melting) (NTP, 1992)
Density1.51 (NTP, 1992) - Denser than water; will sink
SolubilityInsoluble (NTP, 1992)
AppearanceTerephthalic acid is a white powder. (NTP, 1992)
Also Known As100-21-0; p-Phthalic acid; 1,4-Benzenedicarboxylic acid; benzene-1,4-dicarboxylic acid; p-Dicarboxybenzene; 1,4-dicarboxybenzene; p-Benzenedicarboxylic acid; p-Carboxybenzoic acid; Acide terephtalique; Tephthol
CategoryAcids

What is Terephthalic acid?

Terephthalic acid is a benzenedicarboxylic acid carrying carboxy groups at positions 1 and 4. One of three possible isomers of benzenedicarboxylic acid, the others being phthalic and isophthalic acids. It is a conjugate acid of a terephthalate(1-).

Formula & Notation

C8H6O4

IUPAC Name: terephthalic acid

Other Names / Synonyms: 100-21-0; p-Phthalic acid; 1,4-Benzenedicarboxylic acid; benzene-1,4-dicarboxylic acid; p-Dicarboxybenzene; 1,4-dicarboxybenzene; p-Benzenedicarboxylic acid; p-Carboxybenzoic acid; Acide terephtalique; Tephthol

Properties & Characteristics

Appearance: Terephthalic acid is a white powder. (NTP, 1992). Molecular formula: C8H6O4. Molecular weight: 166.13 g/mol. Boiling point: greater than 572 °F at 760 mmHg (sublimes without melting) (NTP, 1992). Melting point: Sublimes (NTP, 1992). Density: 1.51 (NTP, 1992) - Denser than water; will sink. Solubility: Insoluble (NTP, 1992). Vapor pressure: 0.0000092 [mmHg]. LogP: 2.

Physical Data

PropertyValue
Melting PointSublimes (NTP, 1992)
Boiling Pointgreater than 572 °F at 760 mmHg (sublimes without melting) (NTP, 1992)
Density1.51 (NTP, 1992) - Denser than water; will sink
Molecular Weight166.13
SolubilityInsoluble (NTP, 1992)
AppearanceTerephthalic acid is a white powder. (NTP, 1992)

Uses & Applications

Used in industrial chemical synthesis, fertilizer production, battery electrolytes, metal processing, and laboratory acid-base reactions.

Safety Information

Corrosive. Causes severe burns to skin, eyes, and respiratory tract. Wear appropriate PPE including gloves, goggles, and lab coat. Consult SDS before use.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Terephthalic acid
Formula C8H6O4
CAS Number 100-21-0
Molecular Weight 166.13
Category Acids
Synonyms 100-21-0; p-Phthalic acid; 1,4-Benzenedicarboxylic acid; benzene-1,4-dicarboxylic acid; p-Dicarboxybenzene; 1,4-dicarboxybenzene; p-Benzenedicarboxylic acid; p-Carboxybenzoic acid; Acide terephtalique; Tephthol

Frequently Asked Questions

Terephthalic acid is a benzenedicarboxylic acid carrying carboxy groups at positions 1 and 4. One of three possible isomers of benzenedicarboxylic acid, the others being phthalic and isophthalic acids. It is a conjugate acid of a terephthalate(1-).

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Editorial standards: Chemical data is sourced from peer-reviewed literature, CAS Registry, NIST WebBook, and PubChem. Safety information reflects guidance from OSHA, ECHA, and IAEA. For educational purposes only — always consult official SDS documentation and qualified professionals before handling chemicals.