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Phthalic acid (6362 views - Material Database)

Phthalic acid is an aromatic dicarboxylic acid, with formula C6H4(CO2H)2. It is an isomer of isophthalic acid and terephthalic acid. Although phthalic acid is of modest commercial importance, the closely related derivative phthalic anhydride is a commodity chemical produced on a large scale.
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Phthalic acid

Phthalic acid

Phthalic acid
Phthalic acid
Names
Preferred IUPAC name
Benzene-1,2-dicarboxylic acid
Other names
1,2-Benzenedioic acid
Phthalic acid
Benzene-1,2-dioic acid
ortho-Phthalic acid
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.001.703
EC Number 201-873-2
Properties
C8H6O4
Molar mass 166.14 g/mol
Appearance white solid
Density 1.593 g/cm3, solid
Melting point 207 °C (405 °F; 480 K)[4]
0.6 g / 100 mL [1][2]
Acidity (pKa) 2.89, 5.51[3]
-83.61·10−6 cm3/mol
Hazards
NFPA 704
Flammability code 0: Will not burn. E.g., waterHealth code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroformReactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogenSpecial hazards (white): no code
0
2
0
Related compounds
Isophthalic acid
Terephthalic acid
Related compounds
Phthalic anhydride
Phthalimide
Phthalhydrazide
Phthaloyl chloride
Benzene-1,2-
dicarboxaldehyde
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Phthalic acid is an aromatic dicarboxylic acid, with formula C6H4(CO2H)2. It is an isomer of isophthalic acid and terephthalic acid. Although phthalic acid is of modest commercial importance, the closely related derivative phthalic anhydride is a commodity chemical produced on a large scale.[5]

Production

Phthalic acid is produced by the catalytic oxidation of naphthalene or ortho-xylene directly to phthalic anhydride and a subsequent hydrolysis of the anhydride.[5]

Phthalic acid was first obtained by French chemist Auguste Laurent in 1836 by oxidizing naphthalene tetrachloride. Believing the resulting substance to be a naphthalene derivative, he named it "naphthalic acid".[6] After the Swiss chemist Jean Charles Galissard de Marignac determined its correct formula,[7] Laurent gave it its present name.[8] Manufacturing methods in the nineteenth century included oxidation of naphthalene tetrachloride with nitric acid, or, better, oxidation of the hydrocarbon with fuming sulfuric acid, using mercury or mercury(II) sulfate as a catalyst.

Reactions and uses

Phthalic acid crystals

It is a dibasic acid, with pKa's of 2.89 and 5.51. The monopotassium salt, potassium hydrogen phthalate is a standard acid in analytical chemistry. Typically phthalate esters are prepared from the widely available phthalic anhydride. Reduction of phthalic acid with sodium amalgam in the presence of water gives the 1,3-cyclohexadiene derivative.[9]

Isomers

Phthalic acid is one of three isomers of benzenedicarboxylic acid, the others being isophthalic acid and terephthalic acid. Sometimes the term "phthalic acids" is used to refer to this family of isomers, but in the singular, "phthalic acid", refers exclusively to the ortho- isomer.

  phthalic acid     isophthalic acid     terephthalic acid
  (ortho-phthalic acid)     (meta-phthalic acid)     (para-phthalic acid)

Safety

The toxicity of phthalic acid is low with LD50 (mouse) of 550 mg/kg. However, many phthalate esters have been implicated as endocrine disruptors.

Biodegradation

The bacteria Pseudomonas sp. P1 degrades phthalic acid.[10]

See also



This article uses material from the Wikipedia article "Phthalic acid", which is released under the Creative Commons Attribution-Share-Alike License 3.0. There is a list of all authors in Wikipedia

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