Chapter 4: Sugar-based hydrotropes: preparation, properties and applications

Hydrotropes are a class of compounds widely used in industrial applications for their outstanding ability to enhance the aqueous solubility of hydrophobic compounds and surfactants. Very different chemical families can lead to a hydrotropic behaviour and the hydrotropy phenomenon has not been clearly elucidated so far. No definite structure-properties relationships have been established either. The common feature is that hydrotropes exhibit amphiphilicity and can be regarded as weak surfactants, with some similarities in their behaviours in water. This chapter focuses on hydrotropes obtained from sugars and polyols, such as glycerol, sorbitol and isosorbide, which represent relatively new and promising alternatives to the currently used hydrotropes from petroleum origin. Emphasis is put on the preparation of such amphiphiles and on their specific physico-chemical properties.