Final Report Summary - RENOVACARB (Novel applications of renewable based molecules for the production of cyclic carbonates and polycarbonates) Metal and organo-catalysed carbon dioxide (CO2) fixation is a feasible strategy for the preparation of new and sustainable chemicals and materials. RENOVACARB aimed at preparing novel cyclic carbonates and polycarbonate based materials exploiting carbon dioxide conversion reactions on easily obtainable renewable-based compounds, most of which have never been used for this purpose before. Project development focused on the overall process sustainability: (a) developing new environmentally friendly transformation protocols; (b) optimizing selective CO2 cycloaddition/alternate condensation reactions for the preparation of novel renewable-based cyclic and (poly)carbonates; (c) designing novel and simplified catalytic one-pot CO2 conversion protocols for non-functionalized renewable-based molecules; (d) preparing novel structural complex polycarbonates by alternate CO2 polycondensation reactions with renewable-based synthons blends. The resulting molecules and materials have been characterized and evaluated for practical applications. RENOVACARB was designed to develop simple and feasible strategies for renewable resources exploitation by incorporation of CO2 into added value molecules and materials, offering tangible alternatives to petroleum derived feedstocks. RENOVACARB targeted the preparation of new cyclic carbonates molecules and polycarbonate based materials, starting from: a) anthropogenic CO2, which can be regarded as a Carbon Cycle reactant; b) molecules derived from manufacturing wastes of products of the plants’ Carbon Cycle (e.g. terpenes and terpenoids from food and wood industry).The work performed since the beginning of the project included: a) the preparation of suitable terpene derived starting materials (if not commercially available); b) preliminary optimization studies on M-catalyzed CO2 cycloaddition reactions with challenging substrates, such as internal (disubstituted) cyclic oxiranes; c) preparation of bio-derived bicyclic carbonates, obtained via M-catalyzed CO2 cycloaddition reactions with terpene derived trisubstituted bicyclic oxiranes; d) preparation of bio-derived cyclic carbonates via M-catalyzed CO2 cycloaddition reactions with trisubstituted oxiranes derived from linear terpene scaffolds.The main results obtained during the development of the project include: a) preparation of cyclic carbonates derived from internal (bi)cyclic oxiranes: this topic was seldom addressed in the state-of-the-art with limited scope and poor selectivity. We were able to optimize a catalytic approach characterized by (mild) sustainable reaction conditions and to apply it to a wide substrate scope. Further to this, the resulting cyclic carbonates could be readily transformed into the corresponding cis-diols, devising a simple, sustainable protocol for the preparation of scaffold of pharmaceutical interest; b) preparation of (bi)cyclic carbonates starting from bicyclic trisubstituted oxiranes, easily obtainable by functionalization of cheap and abundant renewable based cyclic terpenes. A widely applicable synthetic methodology was optimized, relying on an Al(III) amino(trisphenolate) based catalytic system. Conditions were optimized in order to favour the formation of the cyclic carbonate product rather than the competing poly(carbonate); c) preparation of cyclic carbonates starting from trisubstituted oxiranes derived from linear terpene scaffolds. The corresponding terpene derived cyclic carbonates were obtained in satisfactory yields (50 – 60 %) and moderate selectivity when using an Al(III) amino(trisphenolate) based catalytic system. The behaviour observed for CO2 coupling with less reactive linear trisubstituted epoxides, gave useful hints and insights on the overall reaction mechanism.RENOVACARB was designed to improve the career of the Experienced Researcher by acquiring new technical skills on synthesis, catalysis and material science, new knowledge on the preparation of CO2 based molecules and new applications of renewable-based molecular synthons. The expected preparation of new sustainable molecules and materials resulted in several different dissemination activities, including publication of research results in peer-reviewed high-quality international journals and communications at specialized international meetings. RENOVACARB’s strong interdisciplinary connotation fostered new opportunities for fruitful academic and industrial collaborations specifically towards selected applications of the expected research results, consolidating the Experienced Researcher, Scientist in Charge and Host Institution international expertise on sustainable chemistry. The relevance and timeliness of the proposed CO2 fixation on renewable-based biomass research topic has contributed in strengthening Europe’s commitment to sustainable development while adding new multi-disciplinary cutting edge expertise to the European Research Area.
