Usage des microondes pour l'extraction et la fonctionnalisation de molecules naturelles ou biosourcees (Using microwaves to extract and functionalize natural or bio-based molecules)

Faced with traditional heating techniques, microwave irradiation allows quick energy supply for instantaneous heating. Usual organic solvents may be suppressed, replaced by aqueous media, bio-based or renewable solvents⋯ These properties allow this process perfectly answering the "green chemistry" criteria. Two examples on using this process with bio-based materials are presented: the extraction of saponins from soap nuts and their applications to latex preparation, and the chemical modification of a polysaccharide, the chitosan. The first example reports the efficiency of microwaves in terms of time and yield during the extraction of bio-based molecules, a surfactant. The latter, tested for the synthesis of latex, usefully replaces non-ionic ethoxylated polyphenols-like surfactants of which degradation products may be known as priority substances in accordance with the European directive on water. The second one highlights the process to efficiently modify chitosan with a strong optimisation of reaction times.