Terephthalic acid is a carboxylic acid. Terephthalic acid donates hydrogen ions if a base is present to accept them. This "neutralization" generates substantial amounts of heat and produces water plus a salt.
China is by far the largest TPA producer in the world and accounted for a share of about 28% in 2009. Other major producers are the Republic of Korea, Taiwan and Thailand. The latter three export about half of the TPA produced, accounting for nearly 80% of the global trade, with the rest consumed in PET solid-state applications.