Phthalic acid (IUPAC systematic name: benzene-1,2-dicarboxylic acid) is an aromatic dicarboxylic acid, with formula C₆H₄(COOH)₂. It is an isomer of isophthalic acid and terephthalic acid.

Dimethyl terephthalate (DMT) is an ester of terephthalic acid and methanol and is used in the production of polyesters, including polyethylene terephthalate and polytrimethylene terephthalate. It consists of benzene with methyl ester groups attached in the para position, or to the first and fourth carbon atoms.

Dimethyl terephthalate (DMT) is an ester of terephthalic acid and methanol and is used in the production of polyesters, including polyethylene terephthalate and polytrimethylene terephthalate. It consists of benzene with methyl ester groups attached in the para position, or to the first and fourth carbon atoms.

Low-molecular-weight esters have been available to the PVC compounder for many years. They have found a significant niche in the performance vs. permanence compromise as a compound ingredient that provides manufacturing efficiency or some special property with adequate permanence for many vinyl applications. In many respects, low-molecular-weight esters are the processing aids of the plasticizer family. This group of plasticizers may be said to include C₄ to C₇ dialkyl phthalates, the benzyl phthalates and the benzoic acid esters. This paper will introduce and compare di-n-hexyl phthalate (DNHP) to other phthalates against which it will directly compete.

Bis(2-ethylhexyl)phthalate, commonly abbreviated DEHP, is an organic compound with the formula C₆H₄(CO₂C₈H₁₇)₂. It is the most important "phthalate," being the diester of phthalic acid and the branched-chain 2-ethylhexanol. This colourless viscous liquid is soluble in oil, but not in water. It possesses good plasticizing properties. Being produced on a massive scale by many companies, it has acquired many names and acronymns, including BEHP, di-2-ethyl hexyl phthalate, as well as dioctyl phthalate (DOP).