Terephthalic acid - rice steamers - steamer cooker

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					Properties Terephthalic acid is poorly soluble in water and alcohols,
consequently up until around 1970 most crude terephthalic acid was
converted to the dimethyl ester for purification. It sublimes when
heated. Production Terephthalic acid is produced by oxidation of p-
xylene by oxygen in air: The oxidation is conducted using acetic acid as
solvent and a catalyst composed of cobalt and manganese salts, using a
bromide promoter. The yield is nearly quantitative. The most problematic
impurity is 4-formylbenzoic acid, which is removed by hydrogenation of a
hot aqueous solution. The solution is then cooled in a stepwise manner to
crystallize highly pure terephthalic acid. Alternatively, but not
commercially significant, is the so-called "Henkel process" or "Raecke
process," named after the company and patent holder, respectively. This
process involves the rearrangement of phthalic acid to terephthalic acid
via the corresponding potassium salts. Terephthalic acid can be prepared
in the laboratory by oxidizing various para-disubstituted derivatives of
benzene including Caraway Oil or a mixture of cymene and cuminol with
chromic acid. Applications Virtually the entire world's supply of
terephthalic acid and dimethyl terephthalate are consumed as precursors
to polyethylene terephthalate (PET). World production in 1970 was around
1.75 million tonnes. By 2006, global purified terephthalic acid (PTA)
demand had exceeded 30 million tonnes. In the research laboratory,
terephthalic acid has been popularized as a component for the synthesis
metal-organic frameworks. References ^ CHEMINFO: Terephthalic acid ^
Yoshiro Ogata, Masaru Tsuchida, Akihiko Muramoto (1957). "The Preparation
of Terephthalic Acid from Phthalic or Benzoic Acid". Journal of the
American Chemical Society 79 (22): 60056008.
doi:10.1021/ja01579a043.  ^ Yoshiro Ogata, Masaru Hojo, Masanobu
Morikawa (1960). "Further Studies on the Preparation of Terephthalic Acid
from Phthalic or Benzoic Acid". Journal of Organic Chemistry 25 (12):
20822087. doi:10.1021/jo01082a003.  ^ Richard J. Sheehan,
"Terephthalic Acid, Dimethyl Terephthalate, and Isophthalic Acid" in
Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim,
2002. doi:10.1002/14356007.a26_193 Article Online Posting Date: June 15,
2000. 1911 Encyclopedia External links and further reading Basic Organic
Chemistry: Part 5, Industrial Products, J.M. Tedder, A. Nechvatal, A.H.
Tubb (editors), John Wiley & Sons, Chichester, UK (1975).
International Chemical Safety Card 0330
Categories: Dicarboxylic acids Monomers


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