Phthalic Acid

(redirected from Phthalimides)
Also found in: Dictionary, Thesaurus, Medical.

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 It might be outdated or ideologically biased.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 ?
Phthalimide compounds containing methoxy and nitro groups in the aromatic ring showed strong LOX activity as compare to the presence of chloride and methyl groups in the ring.
Through the optimization of reaction, phthalimide derivatives were obtained in excellent yields through facile one-pot mild condition reaction of phthalic acid with aryl amines that was catalyzed by L-proline.
Eliezer, "Design, synthesis and antiinflammatory activity of novel phthalimide derivatives, structurally related to thalidomide," Bioorganic and Medicinal Chemistry Letters, vol.
Alexandre et al., "Synthesis and anti-inflammatory activity of phthalimide derivatives, designed as new thalidomide analogues," Bioorganic and Medicinal Chemistry, vol.
Khalid, "3D-QSAR for [alpha]-glucosidase inhibitory activity of N-(phenoxyalkyl) phthalimide derivatives," International Journal of Recent Research and Applied Studies, vol.
Clarice, "Synthesis and in vitro anti Mycobacterium tuberculosis activity of a series of phthalimide derivatives," Bioorganic and Medicinal Chemistry, vol.
Singh, "Recent advances in the chemistry of phthalimide analogues and their therapeutic potential," Mini Review in Medicinal Chemistry, vol.