Phthalic Acid

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phthalic acid

[′thal·ik ′as·əd]
(organic chemistry)
C6H4(CO2H)2 Any of three isomeric benzene dicarboxylic acids; the ortho form is usually called phthalic acid, comprises alcohol-soluble, colorless crystals decomposing at 191°C, slightly soluble in water and ether, is used to make dyes, medicine, and synthetic perfumes, and as a chemical intermediate, and is also known as benzene orthodicarboxylic acid; the para form, known as terephthalic acid, is used to make polyester resins (Dacron) and as poultry feed additives; the meta form is isophthalic acid.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Phthalic Acid


(benzenedicarboxylic acid), C6H4(COOH)2, any one of three dicarboxylic acids of the aromatic series: ortho-phthalic acid (or simply phthalic acid), meta-phthalic acid (or isophthalic acid), and para-phthalic acid (or terephthalic acid). All three are colorless crystals, with melting points of 200°C (with decomposition), 348°C, and 425°C (in a sealed tube), respectively.

ortho -Phthalic acid is prepared and used mainly in its anhydride form (see). Of practical importance are the esters of ortho-phthalic acid C6H4(COOR)2, which are liquids with high boiling points; they are used as plasticizers for polyvinyl chloride, polystyrene, and many other polymers (for example, dibutyl phthalate and dioctyl phthalate) and serve as manometric liquids and insect repellents, such as dimethyl phthalate. The dinitrile of ortho-phthalic acid (phthalonitrile) is used in the production of phthalocyanine dyes and polyphthalocyanines. Also of practical importance are the cyclic imide (phthalimide) and dichloranhydride (phthalyl chloride) of ortho-phthalic acid, as well as phthalylsulfathiazole (Ftalazol). Polyester resins based on ortho-phthalic acid and polyhydric alcohols, such as glycerin and pentaerythritol, are widely used; these are called glyptal and penta resins, respectively.

meta-Phthalic acid and para-phthalic acid are prepared by the oxidation of meta-xylene and para-xylene, respectively. They serve as the basis for the commercial production of aromatic polyamides, such as poly-m-phenyleneisophthalamide, and in the production of polyarylates. The interaction of para-phthalic acid or its dimethyl ester with ethylene glycol yields polyethylene terephthalate, which is used in the manufacture of polyester fibers.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
1,2-benzenedicarboxylic acid, di-C8-10-brancbed alkyl esters, C9-rich and di- "isononyl" phthalate (DINP).
The term "phthalates" refers to the diesters of 1,2-benzenedicarboxylic acid, better known as phthalic acid.
The most frequently detected compounds at two sampling sites from KTD were bisphenol A (BPA), octylphenol (OP), 1,2-benzenedicarboxylic acid, bis(2-ethylhexyl) ester (DEHP) and 1,2-benzenedicarboxylic acid, bis(methylpropyl) ester (DBP).
The identified components were octane, 4isopropenyl-1-methyl-1-cyclohexene, 2-nonanone, nonanal, 1-methyl-5,6-divinyl-1-cyclohexene, 2-decanone, decanal, 2undecanone, 2-dodecanone, 2-tridecanone, 1-heptadecene, pentacosane, and 1,2-benzenedicarboxylic acid. Moreover, 2undecanone (87.18%) was the main component of RCEO, consistently with previous findings [20, 33-35] (68.95%, 47.7%, 69.23%, and 77.18%, resp.).
: Summary: Three acid-base compounds with supramolecular architectures, namely, (1,2-H2bdc)(dmt) (1), (trans-1,4-H2ccdc)0.5(phdat) (2) and (1,3-H2bdc)(phdat) (3) (1,2-H2bdc 1,2-benzenedicarboxylic acid, trans-1, 4-H2ccdc trans-1, 4-cyclohexanedicarboxylic acid, 1,3-H2bdc 1,3-benzenedicarboxylic acid, dmt 2,4-diamino-6-methyl-s-triazine, phdat 2,4-diamino-6-phenyl-s-triazine) have been synthesized and characterized by IR spectra, elementalanalyses, single-crystal X-ray diffractions and TGA.Keywords: sandwich architecture, hydrogen bonding, p-p stacking interactions, supramolecular complexesIntroduction