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Chemical Properties

CAS Registry Number: 88-99-3

Selected information from two of the National Library of Medicine's databases: ChemIDPlus2 and HSDB3.

Names 1

  • 1,2-Benzenedicarboxylic Acid (9ci)
  • Phthalic acid

Structure

Chemical Structure for Chemical Abstracts Service Registry Number 88-99-3 from NLM

Synonyms (Sources: NTP,HSDB,RTECS,MESH)2

  • 4-09-00-03167 (Beilstein Handbook Reference)
  • Acide phtalique [French]
  • BRN 0608199
  • Benzene-1,2-dicarboxylic acid
  • HSDB 1339
  • Kyselina ftalova [Czech]
  • o-Benzenedicarboxylic acid
  • o-Dicarboxybenzene
  • o-Phthalic acid

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Other Registry Numbers2

  • 4401-64-3

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Chemical Properties3

Property Description
Boiling Point
  • Decomposes
Color/Form
  • Colorless crystals
  • Plates from water
Corrosivity
  • None Found
Critical Temperature & Pressure
  • Critical temperature = 800.00 K; Critical pressure = 3.9500X10+6 Pa
Density/Specific Gravity
  • 1.593 g/cu cm at 15 deg C
Dissociation Constants
  • pKa1 = 2.76; pKa2 = 4.92 at 25 deg C
Heat Of Combustion
  • 19657.03 J/g
Heat Of Vaporization
  • None Found
Melting Point
  • Decomposes at 230 deg C
Molecular Weight
  • 166.13
Odor
  • None Found
Other Chemical/Physical Properties
  • ...When rapidly heated, forming phthalic anhydride and water
  • Boiling point = 598.00 K (Based on predicted value for phthalic acid by Meissner's method with a suitable adjustment for isomerism based on similar compound relationships.)
  • Density/specific gravity: 9.4864 kmol/cu m @ 20 deg C
  • Heat of fusion = 315.3 J/g
  • Heat of solution = 123.55 J/g at 25 deg C
  • Henry's Law constant = 2.1X10-11 atm-cu m/mole at 25 deg C (est)
  • Hydroxyl radical reaction rate constant = 1.24X10-12 cu cm/molecule-sec at 25 deg C (est)
  • Melting point = 464.15 K (determined in a sealed tube)
  • Melting point: ca. 210 deg C, converted into phthalic anhydride with the elimination of water.
  • Specific heat = 1138 J/kg-K at 300 K
  • Specific heat of solid (0-99 deg C) 1.214 J/g-K
  • Triple point temperature and pressure = 464.15 K (estimated to be equal to the melting point), 7.8183X10+3 Pa
Relative Evaporation Rate
  • None Found
Solubilities
  • 1 g dissolves in 160 ml water, 10 ml alc, 205 ml ether, 5.3 ml methanol; practically insol in chloroform
  • In water, 6,965 mg/L at 25 deg C
  • Soluble in alcohol; sparingly soluble in ether
Spectral Properties
  • 1H NMR: 17103 (Sadtler Research Laboratories Spectral Collection)
  • IR: 1603 (Coblentz Society Spectral Collection)
  • MASS: 1080 (Atlas of Mass Spectral Data, John Wiley & Sons, New York); 21933 (NIST/EPA/MSDC Mass Spectral Database, 1990 version)
  • MAX ABSORPTION (ALCOHOL): 225 NM (LOG E= 3.88); 275 NM (LOG E= 3.08); SADTLER REF NUMBER: 6272 (IR, PRISM); 8442 (IR, GRATING)
  • UV: 1730 (Sadtler Research Laboratories Spectral Collection)
Surface Tension
  • None Found
Taste
  • None Found
Vapor Density
  • 5.73 (AIR= 1)
Vapor Pressure
  • 6.36X10-7 mm Hg at 25 deg C
Viscosity
  • None Found
log P (octanol-water)
  • log Kow = 0.73
pH
  • None Found

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Uses3

  • ... Medicine ... Organic synthesis. Analytical reagent. **PEER REVIEWED**
  • Dyes, phenolphthalein, phthalimide, anthranilic acid, synthetic perfumes, laboratory reagent. **PEER REVIEWED**

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Notes (Sources: NTP,HSDB,RTECS,MESH)2

  • None Found.

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Superlist Classes2

  • None Found

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Links to Additional Information2

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Footnotes

1 Source: the NTP's CEBS database.

2 Source: the National Library of Medicine's ChemIDPlus, 02/28/2017.

3 Source: the National Library of Medicine's Hazardous Substance Database, 02/28/2017.

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