Phthalic acid

Phthalic acid
	Phthalic acids
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
CAS Number	88-99-3 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:29069 ;
ChemSpider	992 ;
ECHA InfoCard	100.001.703
EC Number	201-873-2;
PubChem CID	1017;
UNII	6O7F7IX66E ;
CompTox Dashboard (EPA)	DTXSID8021484 ;
	InChI InChI=1S/C8H6O4/c9-7(10)5-3-1-2-4-6(5)8(11)12/h1-4H,(H,9,10)(H,11,12) Key: XNGIFLGASWRNHJ-UHFFFAOYSA-N ; InChI=1/C8H6O4/c9-7(10)5-3-1-2-4-6(5)8(11)12/h1-4H,(H,9,10)(H,11,12) Key: XNGIFLGASWRNHJ-UHFFFAOYAX;
	SMILES OC(=O)c1ccccc1C(=O)O;
Properties
Chemical formula	C8H6O4
Molar mass	166.132 g/mol
Appearance	white solid
Density	1.593 g/cm3, solid
Melting point	207 °C (405 °F; 480 K)
Solubility in water	0.6 g / 100 mL
Acidity (pKa)	2.89, 5.51
Magnetic susceptibility (χ)	-83.61·10−6 cm3/mol
Hazards
NFPA 704 (fire diamond)	2 0 0
Related compounds
Related carboxylic acids	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). verify (what is ?) Infobox references

In organic chemistry, phthalic acid is an aromatic dicarboxylic acid, with formula C₆H₄(CO₂H)₂ and structure HO(O)C−C₆H₄−C(O)OH. Although phthalic acid is of modest commercial importance, the closely related derivative phthalic anhydride is a commodity chemical produced on a large scale.^[4] Phthalic acid is one of three isomers of benzenedicarboxylic acid, the others being isophthalic acid and terephthalic acid.

^ "PHTHALIC ACID". hazard.com.
^ Brown, H.C., et al., in Baude, E.A. and Nachod, F.C., Determination of Organic Structures by Physical Methods, Academic Press, New York, 1955.
^ Several melting points are reported, for example: (i) 480. K (NIST website), (ii) 210−211 °C with decomposition (Sigma-Aldrich on-line), (iii) 191 °C in a sealed tube (Ullmann's Encyclopedia of Industrial Chemistry), (iv) 230 °C with conversion to phthalic anhydride and water (J.T.Baker MSDS).
^ Lorz, Peter M.; Towae, Friedrich K.; Enke, Walter; et al. (2007). "Phthalic Acid and Derivatives". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a20_181.pub2. ISBN 978-3-527-30673-2.

Names
Phthalic acids

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
CAS Number	88-99-3^Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:29069^N
ChemSpider	992^N
ECHA InfoCard	100.001.703
EC Number	201-873-2
PubChem CID	1017
UNII	6O7F7IX66E^Y
CompTox Dashboard (EPA)	DTXSID8021484
InChI InChI=1S/C8H6O4/c9-7(10)5-3-1-2-4-6(5)8(11)12/h1-4H,(H,9,10)(H,11,12)^N Key: XNGIFLGASWRNHJ-UHFFFAOYSA-N^N InChI=1/C8H6O4/c9-7(10)5-3-1-2-4-6(5)8(11)12/h1-4H,(H,9,10)(H,11,12) Key: XNGIFLGASWRNHJ-UHFFFAOYAX
SMILES OC(=O)c1ccccc1C(=O)O
Properties
Chemical formula	C₈H₆O₄
Molar mass	166.132 g/mol
Appearance	white solid
Density	1.593 g/cm³, solid
Melting point	207 °C (405 °F; 480 K)^[3]
Solubility in water	0.6 g / 100 mL ^[1]
Acidity (pK_a)	2.89, 5.51^[2]
Magnetic susceptibility (χ)	-83.61·10⁻⁶ cm³/mol
Hazards
NFPA 704 (fire diamond)	2 0 0
Related compounds
Related carboxylic acids	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). N verify (what is ^YN ?) Infobox references