Terephthalic acid
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| Terephthalic acid | |
|---|---|
| Image:Terephthalic-acid-2D-skeletal.png | |
| Other names | Benzene-1,4-dicarboxylic acid para-Phthalic acid TPA PTA |
| Identifiers | |
| CAS number | |
| RTECS number | WZ0875000 |
| SMILES | C1=CC(=CC=C1C (=O)O)C(=O)O |
| Properties | |
| Molecular formula | C6H4(COOH)2 |
| Molar mass | 166.13 g/mol |
| Appearance | white crystals or powder |
| Density | 1.522 g/cm³ |
| Melting point |
427°C in a sealed tube (sublimes at 402°C (675 K) in air) |
| Boiling point |
sublimes |
| Solubility in water | 1.7g in 100g H2O at 25°C |
| Solubility | Soluble in Dimethyl sulfoxide, DMF, and alkalies. Slightly soluble in ethanol, methanol, formic acid and sulfuric acid. [1] |
| Acidity (pKa) | 3.54 at 25°C [1] |
| Structure | |
| Dipole moment | zero |
| Hazards | |
| EU classification | not listed |
| Related Compounds | |
| Related carboxylic acids | Phthalic acid Isophthalic acid Benzoic acid p-Toluic acid |
| Related compounds | p-Xylene Polyethylene terephthalate Dimethyl terephthalate |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references | |
Terephthalic acid is one isomer of the three phthalic acids. It finds important use as a commodity chemical, principally as a starting compound for the manufacture of polyester (specifically PET), used in clothing and to make plastic bottles. It is also known as 1,4-benzenedicarboxylic acid, and it has the chemical formula C6H4(COOH)2. It has recently become an important component in the development of hybrid framework materials.
History
Phthalic acid (the ortho isomer of terephthalic acid) was obtained by French chemist Auguste Laurent in 1836 by oxidizing naphthalene tetrachloride, and, believing the resulting substance to be a naphthalene derivative, he named it naphthalenic acid. Swiss chemist Jean Charles Galissard de Marignac determined its formula and showed Laurent’s supposition to be incorrect, upon which Laurent gave it its present name.
Properties
It is almost insoluble in water, alcohol and ether; it sublimes rather than melting when heated. This insolubility makes it relatively awkward to work with, and up until around 1970 much crude terephthalic acid was converted to the dimethyl ester for purification.
Production
Terephthalic acid can be formed in the laboratory by oxidizing para-diderivatives of benzene, or best by oxidizing caraway oil, a mixture of cymene and cuminol, with chromic acid.
Image:Terephthalic-acid-chemical-synthesis.png
On an industrial scale, terephthalic acid is produced, similar to benzoic acid, by oxidation of p-xylene by oxygen from air. This is done using acetic acid as solvent, in the presence of a catalyst such as cobalt-manganese, using a bromide promoter. Alternatively, it can be made via the Henkel process, which involves the rearrangement of phthalic acid to terephthalic acid via the corresponding potassium salts. The terephthalic acid is and dimethyl terephthalate, in turn, often used as a monomer component in the production of polymers, principally polyethylene terephthalate (polyester or PET). World production in 1970 was around 1.75 million tonnes.[2]. By 2006, global PTA demand had substantially exceeded 30 million tonnes.
References
 |
The references in this article would be clearer with a different or consistent style of citation, footnoting, or external linking. |
- 1911 Encyclopedia
- Basic Organic Chemistry: Part 5, Industrial Products, J.M. Tedder, A. Nechvatal, A.H. Tubb (editors), John Wiley & Sons, Chichester, UK (1975).
External links
de:Terephthalsäure fr:Acide téréphtalique it:Acido tereftalico nl:Tereftaalzuur ja:テレフタル酸 no:Tereftalsyrefi:Tereftaalihappo
Acknowledgement and Attribution Regarding Sources of Content
Some of the initial content on this page may be incorporated in part from copyleft sources in the public domain including wikis such as Wikipedia and AskDrWiki. Drug information for patients came from the The National Library of Medicine. Infectious disease information may have come from the Centers for Disease Control (CDC). Differential Diagnoses are drawn from clinicians as well as an amalgamation of 3 sources: 1.The Disease Database; 2. Kahan, Scott, Smith, Ellen G. In A Page: Signs and Symptoms. Malden, Massachusetts: Blackwell Publishing, 2004:3; 3. Sailer, Christian, Wasner, Susanne. Differential Diagnosis Pocket. Hermosa Beach, CA: Borm Bruckmeir Publishing LLC, 2002:7 .
