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 It might be outdated or ideologically biased.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 ?
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.
Phthalic acid esters are endocrine-disrupting compounds, which have been shown to reduce the diversity of microbial communities and decline crop quality [31], and are toxic to most aquatic organisms including algae [32].
The result showed that the main components were phthalic acid, butyl hexyl ester (42.85%), hexanedioic acid, bis(2-ethylhexyl) ester (5.22%), phthalic acid, 2ethylhexyl hexyl ester (13.96%), 2,6,10,14, 18,22tetracosahexaene, 2,6,10, 15, 19,23-hexamethyl-, (allE)-(3.13%), 1H-indole, 1-methyl-2- phenyl(1.07%), 2-amino-4-hydroxy-6,8-dimethyl-7 (8H)-pteridinone (11.69%), benzo[h] quinoline, 2,4dimethyl-(1.43%), 2,4,6-cyclo-heptatrien-1-one, 3,5-bis-trimethylsilyl- (2.50%), 3,3,7,11-tetramethyltricyclo [,11)]undecan-1-ol-(1.43%), cyclohexane, 1,1,2-trimethyl-3,5- bis(1-methylethenyl)-, (2[+ or -],32,52)-(16.73%).
Development of a solid-phase microextraction method for the determination of phthalic acid esters in water, Analytica Chimica Acta, 457: 211-223.
mucronata Retention time Components Area (%) Quality 3.882 Propanoic acid 1.16 85 11.505 Cyclopentane 1.77 88 11.818 Hydrazine carboxamide 0.93 80 13.778 Benzamide 1.76 82 18.159 Pentadecanoic acid 0.91 87 18.780 Phthalic acid 1.78 88 25.712 Hexanedioic acid 2.11 93 27.407 2-hydroxy-1-ethyl acetate 22.15 97 27.898 Mono (2-ethylhexyl) ester 2.33 81 28.385 Oxalic acid 0.80 88 29.280 Hexadecyl acetate 0.81 87 Table 7.
Name of the compound RT number 1 Dodecanoic acid 13.776 2 Tetradecanoic acid 16.071 3 1,2-Benzenedicarboxylic 17.189 acid, bis(2- methylpropyl) ester 4 Pentadecanoic acid, 14- 17.842 methyl-, methyl ester 5 n-Hexadecanoic acid 18.176 6 Cystodytin 18.510 7 1-Decanol, 2-hexyl- 18.583 8 10,13-Octadecadienoic 19.469 acid, methyl ester 9 frans-13-Octadecenoic 19.527 acid, methyl ester 10 9,12-Octadecadienoic 19.817 acid (Z,Z)- 11 9,17-Octadecadienal, (Z)- 19.876 12 Phthalic acid, di(2- 23.201 propylpentyl) ester 13 Anthracene, 9-ethyl-9, 25.699 10-dihydro-10-t-butyl- 14 4-Dehydroxy- N-(4,5- 32.148 methylenedioxy-2- nitrobenzylidene) tyramine S.
(7.) "What are the sources' of exposure to eight frequently used phthalic acid esters in Europeans?" M.
Phthalic Acid Esters (PAEs), commonly known as phthalates, are widely used as additives in polymer manufacture as plasticizers.
Comments: Heucorin FR is zinc salt of phthalic acid that combines the properties of a high performance organic corrosion and a highly effective flash/early rust inhibitor.
To determine the protective effects of AS extract and phenolic compounds on A [beta]-induced neurotoxicity, cell were treated with A[[beta].sub.25-35] (15 [micro]M) for 48h in the presence or absence of AS extract (50-500 [micro]g/ml), FA (2-40 [micro]g/ml), phthalic acid (20[micro]g/ml), coumaric acid (20[micro]g/ml), and nicotinic acid (20[micro]g/ml).
The copolyester consists of repeat units of one or more aliphatic dicarboxylic acids, one or more aromatic dicarboxylic acids selected from the group consisting of terephthaliic acid, isophthalic acid and phthalic acid, and a stoichiometric amount of a glycol component consisting of one or more glycols selected from the group consisting of aliphatic glycols and cycloaliphatic glycols.
Highly suitable polycarboxylic acids are, for instance, phthalic acid anhydride, terephthalic acid anhydride, trimellitic acid, adipic acid, and maleic acid.