Изофталевая кислота

Описание

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, iso phthalic acid is used in the production of resins for drink bottles. The high-performance polymer poly benzimidazole is produced from iso phthalic acid.

Химические свойства

Isophthalic acid is a white crystalline powder or needle-like crystals and it’s an isomer of phthalic acid and terephthalic acid.It is insoluble in cold water but soluble in oxygenated solvents and alcohol. It is combustible and finely dispersed particles will form explosive mixtures in air.

Isophthalic Acid (PIA) is mainly used in the production of bottle PET, also used in the production of alkyd resin, polyester resin, also used in the production of photosensitive materials, pharmaceutical intermediates and so on.
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.

Использование

Purified Isophthalic Acid (PIA) is mainly used as intermediate for high performance UPR, resins for coatings, high solids paints, gel coats, modifier of PET for bottles. Product Data Sheet

Подготовка

Iso phthalic acid is produced on the billion kilogram per year 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-sulpho benzoate , or meta - brom benzoate with potassium formate (terephthalic acid is also formed in the last case).
The barium salt (as its hexa hydrate) 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.

Определение

ChEBI: A benzenedicarboxylic acid that is benzene substituted by carboxy groups at position 1 and 3. One of three possible isomers of benzenedicarboxylic acid, the others being phthalic and terephthalic acids.

Общее описание

White solid with a slight unpleasant odor. Sinks in water.

Реакции воздуха и воды

Dust forms explosive mixture in air [USCG, 1999].

Угроза здоровью

May cause slight to moderate irritation of eyes, skin, and mucous membranes on prolonged contact. Ingestion may cause gastrointestinal irritation.

Пожароопасность

Behavior in Fire: Dust forms explosive mixture in air.

Методы очистки

Crystallise the acid from aqueous EtOH. [Beilstein 9 IV 3292.]