Α-HYDROXY FATTY ACIDS AND BIOPOLYMERS: NEW FATES FOR LIPID-ENRICHED FOOD SCRAPS

Biomasses deriving from food scraps represent a growing global issue, as they are hard to recycle and to dispose of. In this work, a new method for the implementation of food-related biomasses was assessed, in order to attain products via environment-friendly chemical processes. Food scraps may be particularly enriched of fatty acids, whose potential is yet to be fully exploited. One new fate for these molecules could be represented by the conversion into new chemical entities, in this case α-hydroxy fatty acids, that have the chance to be used in many different fields, such as cosmetics, pharmaceutical, food and material industries. For this project two food-related biomasses were considered: lanolin and spent coffee grounds. At first, we worked with pure saturated fatty acids, in order to investigate and realise an efficient and as-green-as-possible synthesis of α-hydroxy fatty acids. This was achieved by converting fatty acids to the correspondent α-chlorinated intermediates, using trichloroisocyanuric acid, a non-toxic and environment-friendly reagent, which were then easily transformed into α-hydroxy fatty acids. The reaction pathway developed on saturated fatty acids was successfully applied to the fatty acids extracted from lanolin, a biomass deriving from the scouring of sheep wool. The extraction and fractionation procedures of the biomass were carried out with the aid of an ad-hoc GC-MS and 1H NMR combined method. Subsequently, we decided to use spent coffee grounds, the inevitable by-product of coffee brewing, which, in turn, contained a mixture of saturated and unsaturated fatty acids. For this reason, we performed a deep study for the α-hydroxylation of unsaturated fatty acids, using food-grade oleic acid, still avoiding noxious and polluting reagents and solvents. This new pathway was then employed for the α-hydroxylation of fatty acids extracted from spent coffee grounds. The synthetized products were involved in the production of new biopolymers. Specifically, saturated α-hydroxy fatty acids were used for the synthesis of polylactic acid analogues, with the intent to overcome the drawbacks related to the parent polymer (such as brittleness, low barrier properties and poor thermal resistance). On the other hand, lanolin-derived α-hydroxy fatty acids were implicated in the synthesis of new polymeric biofilms for the protection and conservation of marble manufactures. In light of a collaboration with SIPOL® S.p.a., an industry involved in the production of polyamides and polyesters, we synthetized and characterized six different polyamides, inserting saturated α-hydroxy fatty acids as chain terminators. Then, the byproducts attained from spent coffee grounds after triacylglycerols extraction were used as base for the production of new biocomposites. In particular, these were produced with spent coffee grounds in combination with polybutylene succinate at different concentrations. Moreover, in order to study how the deprivation of lipids would impact the characteristics of the biocomposites, the study was carried out using both native spent coffee grounds and the ones left behind the extraction procedure. Finally, in order to expand our knowledge about the chlorinating properties of trichloroisocyanuric acid, the α-chlorination reaction was also effectively performed on phenylacetic acids in order to attain the correspondent α-chlorinated derivates, which are synthons with great potential but limited by the lack of a simple and generalizable method of preparation from largely available precursors.