Denis Spitzer
Director NS3E Laboratory, France
Title: Spray Flash Evaporation (SFE): A technique for breakthrough chemical engineering challenges
Biography
Biography: Denis Spitzer
Abstract
The Spray Flash Evaporation (SFE) is a novel, innovative technique invented at the French-German research Institute of Saint-Louis (ISL). It permits to tailor and to engineer in a continuous way, organic, hybrid and inorganic nanomaterials in terms of particle sizes, crystallinity, structure and morphology from the laboratory scale to semi-industrial scale. It consists in the continuous spraying of a precursor (or a mixture of precursors), dissolved in an adapted solvent (or mixture of solvents) and heated at temperatures ranging from 130 °C to 160 °C at a pressure around 40 bar, followed by a rapid expansion through a hollow cone nozzle into an atomization chamber (20-50°C, 2-20 mbar. Due to the pressure difference, a very fast crystallization is induced, leading to the formation of nanoparticles, which are trapped by cyclones, filters or electrostatic precursors. This process allows the continuous nanocrystallizing (without any further thermal treatments) of organic, hybrid and inorganic crystallized pure compounds or nanocomposites. In the case of organic mixtures, depending on the kind of intermolecular interactions (Hydrogen bonds, π-π stacking, van der Waals interactions), the SFE technique is able to produce crystalline nanocomposites with dissociated or coupled compounds (core-shell), semi-amorphous or totally amorphous nanocomposites, and even, in the case of strong intermolecular interactions, nanococrystals. For example, in the latter case, different works showed the possibility to obtain nanococrystals such as Caffeine/Oxalic acid (2/1), Caffeine/Glutaric acid (1/1) and Resveratrol/4-aminobenzamid (1/1). The particle sizes, compared to them obtained by processes such as for example classical spray drying, are much smaller and are in this manner very important to enhance dissolution kinetics of drugs, additionally, to increase their bioavailability by the production of Active Pharmaceutical Ingredients (API) based on very small nanococrystals. Elaborating new types of molecular mixtures is also an upcoming challenge of SFE.
