Phthalic Acid

CAS Number 88-99-3
Molecular Formula C8H6O4
Molecular Weight 166.133 g/mol
LogP 0.73
  • Phthalic acid
  • Benzene-1,2-dicarboxylic acid
  • 1,2-Benzenedicarboxylic acid
  • 88-99-3
  • 1,2-Benzenedicarboxylic acid
  • 4-09-00-03167
  • Acide phtalique
  • acido ftalico
  • NSC 5348
  • o-Benzenedicarboxylic acid
  • o-Carboxybenzoic acid
  • o-Dicarboxybenzene
  • Orthophthalic acid
  • Phthalsaure
  • Benzene-1,2-dicarboxylic acid
  • BRN 0608199
  • EINECS 201-873-2
  • O-Phthalic acid
  • Kyselina ftalova
  • UNII-6O7F7IX66E
  • Alizarinate
  • Alizarinic acid
  • M 2
  • Naphthalinate
  • Naphthalinic acid
  • O-Benzenedicarboxylate
  • O-Carboxybenzoate
  • Phthalate
  • Phthalinate
  • Phthalinic acid
  • Sunftal 20
  • ortho-phthalic acid
  • 4401-64-3


Separation of Diacid Hydrophobic and Ion Exchange Modes

Primesep B combines a hydrophobic, reversed-phase mechanism with ion exchange to separate the diacids, fumaric, benzoic, phthalic, naphthoic, and maleic acids. Changing the acetonitrile content of the mobile phase reverses the peak order for naphthoic and maleic acids. Primesep B combines reversed-phase and anion-exchange mechanism with a mobile phase of water, acetonitrile (MeCN, ACN) and trifluoracetic acid (TFA) and UV detection at 250 nm.

Application Analytes:

Benzoic Acid
Dicarboxylic Acids
Fumaric Acid
Maleic Acid
Naphthoic Acid
Phthalic Acid

HPLC Separation of Organics Acids

Primesep D separates organic acids such as fumaric, benzoic, phthalic, naphthoic, and maleic acids by a mixture of anion exchange and reversed phase. Retention times and elution order can be changed by adjusting the percentage of acetonitrile in the mobile. This can not be done by traditional ion-exchange and ion-exclusion chromatography. The HPLC separation uses a mobile phase of water, acetonitrile (MeCN, ACN) and trifluoroacetic acid (TFA) and UV detection at 250 nm.

Application Analytes:

Benzoic Acid
Fumaric Acid
Maleic Acid
Naphthoic Acid
Organic Acids
Phthalic Acid

HPLC Separation of Phthalic Acids using Hydrogen Bonding


Application Analytes:

Phthalic Acid

Separation of Phthalic Acids and Related Impurities

Phthalic acid, phthalic acid isomers, and related products present in the production of phthalic acid were separated on the Primesep D column, based on reversed-phase and in-exchange mechanisms. Neutral, hydrophobic compounds of the phthalic acid production are retained by a reversed-phase mechanism, and phthalic acid and other acidic compounds are retained by a combination of reversed-phase and anion-exchange mechanisms. Resolution and selectivity of this separation can be modified by varying the amount of acetonitrile, buffer concentrations, and buffer pH. This method can be used for monitoring the production cycle of phthalic acid and related impurities.



Column Primesep D, 4.6x150 mm, 5 µm, 100A
Mobile Phase Gradient MeCN - 10-50%, 15 min
Buffer H2SO4 - 0.1%
Flow Rate 1.0 ml/min
Detection UV, 210 nm


Class of Compounds Acid, Hydrophilic, Ionizable
Analyzing Compounds Terephthalaldehyde, Phthalic acid, 4-Carboxybenzaldehyde, Benzoic acid, Terephthalic acid, p –Tolualdehyde, p-Toluic acid

Application Analytes:

Benzoic Acid
Phthalic Acid
Terephthalic Acid
p-Toluic Acid