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Isophthalic acid PIA

(Click here for a model of a molecule of Isophthalic acid PIA)

News about  Isophthalic acid PIA

Isophthalic Acid (PIA) is the industry standard diacid component in high-quality alkyds and polyester resins for industrial coatings and unsaturated polyesters for fiberglass-reinforced plastics applications.

Polyester resins containing PIA exhibit excellent outdoor weathering relative to those containing phthalic anhydride and terephthalic acid. The excellent hardness and high glass transition temperature imparted by PIA leads to improved chemical, stain, humidity, and corrosion resistance required in coatings for industrial maintenance, automotive, aerospace, general metal and coil coating applications. Powder coatings formulated with PIA are used in exterior applications such as patio furniture, lawn mowers, vending machines, and automotive parts.

One of the largest applications for  PIA is in unsaturated polyester resins for high-quality gel coats. The hardness, stain and detergent resistance characteristics of PIA are ideal for polyester solid-surface countertops that are an inexpensive alternative to acrylics.

PIA is supplied as a high-melting, white powder available in a variety of package sizes. For more information or to request a sample, contact an Eastman Technical Service Representative.

Other namesBenzene-1,3-dicarboxylic acid
meta-Phthalic acid
CAS number 121-91-5 Y
PubChem 8496
ChemSpider 8182 Y


Molecular formula C6H4(COOH)2
Molar mass 166.14 g/mol
Appearance White crystalline solid
Density 1.526 g/cm3, Solid
Solubility in water Insoluble in water
Acidity (pKa) 3.46, 4.46[1]
EU classification not listed
Related compounds
Related carboxylic acids Benzoic acid
Phthalic acid (ortho)
Terephthalic acid (para)
Trimesic acid (benzene-1,3,5-tricarboxyllic acid)
Y(what is this?) (verify)
Except where noted otherwise, data are given for materials in their standard state (at 25 C, 100 kPa)
Infobox references
Isophthalic acid is an organic compound with the formula C6H4(CO2H)2. This colourless solid is an isomer of phthalic acid and terephthalic acid. These aromatic dicarboxylic acids are used as precursors (in form of acyl chlorides) to commercially important polymers, e.g. the fire-resistant material Nomex. Mixed with terephthalic acid, isophthalic acid is used in the production of resins for drink bottles. The high-performance polymer polybenzimidazole is produced from isophthalic acid.

Isophthalic acid is produced on the billion kilogram/y scale by oxidizing meta-xylene using oxygen. The process employs a cobalt-manganese catalyst. In the laboratory, chromic acid can be used as the oxidant. It also arises by fusing potassium meta-sulphobenzoate, or meta-brombenzoate with potassium formate (terephthalic acid is also formed in the last case).

The barium salt (as its hexahydrate) is very soluble (a distinction between phthalic and terephthalic acids). Uvitic acid, 5-methylisophthalic acid, is obtained by oxidizing mesitylene or by condensing pyroracemic acid with baryta water.

Related pages.
Epichlorohydrin  Terephthalic acid  Titanium dioxide Neopentylglycol (NPG) Trimellitic anhydride Isophthalic Acid (PIA)  bisphenol A BPA carbon black
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Article/information contributed by.............. Let's Finish it Team

This article is licensed under the  GNU Free Documentation License