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Low solubility of terephthalic acid in common solvents makes its industrial production very difficult and not environmentally benign. Ionic liquids are known for their extraordinary solvent properties, with capability to dissolve a wide variety of materials, from common solvents to cellulose, opening new possibilities to find more suitable solvents for terephthalic acid. This work presents studies on the solubility of terephthalic acid in ionic liquids, and demonstrates that terephthalic acid is soluble in ionic liquids, such as 1-ethyl-3-methylimidazolium diethylphosphate, 1-butyl-3-methylimidazolium acetate, and dialkylimidazolium chlorides up to four times higher than in DMSO. Additionally, the temperature effect and correlation of ionic liquid structure with solubility efficiency are discussed. [ABSTRACT FROM AUTHOR]

Alkyl lactates are produced from lactic acid via esterification, and are used in the production of plastics, paints, solvents and detergents. In the pursuit of an inexpensive, industry-suitable catalyst for this reaction, the application of protic ionic liquids based on nitrogen base and sulphuric acid is proposed. The ionic liquid was synthesised via a simple reaction of triethylamine and a threefold molar excess of sulphuric acid. Water was added to remove the heat of the reaction. Next, the reaction conditions for the model esterification of 2-ethylhexanol with lactic acid without additional solvent were optimised. Exceptionally mild conditions, i.e., a twofold molar excess of alcohol to lactic acid with the addition of an ionic liquid in a catalytic amount (15 mol%) at 60 °C, resulted in high yields of ethyl and 2-ethylhexyl lactates (96–97%). The driving force of this reaction is the production of a biphasic system with immiscible ester during the reaction. This phenomenon makes it possible to overcome the reaction equilibrium. Using an inexpensive ionic liquid, which could be recycled up to five times without diminution in conversion or selectivity, leads to both a greener and a more economically-viable process. [ABSTRACT FROM AUTHOR]