Browsing by Author "Rojas, Rene S."

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    Approach to Circular Chemistry Preparing New Polyesters from Olive Oil
    (2023) Werlinger, Francisca; Caprile, Renato; Cardenas-Toledo, Valentino; Tarraff, Bastian; Mesias-Salazar, Angela; Rojas, Rene S.; Martinez, Javier; Trofymchuk, Oleksandra S.; Flores, Mario E.
    The transformation of cooking oils and their waste intopolyestersis a challenge for circular chemistry. Herein, we have used epoxidizedolive oil (EOO), obtained from cooking olive oil (COO), and variouscyclic anhydrides (such as phthalic anhydride PA, maleic anhydrideMA, and succinic anhydride SA) as raw materials for the preparationof new bio-based polyesters. For the synthesis of these materials,we have used the bis(guanidine) organocatalyst 1 andtetrabutylammonium iodide (Bu4NI) as cocatalyst. The optimalreaction conditions for the preparation of poly(EOO-co-PA) and poly(EOO-co-MA) were 80 degrees C for 5 husing toluene as solvent; however, the synthesis of poly(EOO-co-SA) required more extreme reaction conditions. Furthermore,we have exclusively succeeded in obtaining the trans isomer for MA-polyester.The obtained biopolyesters were characterized by NMR, Fourier transforminfrared, thermogravimetric analysis, and scanning electron microscopyanalyses. Since there are few examples of functionalized and definedcompounds based on olive oil, it is innovative and challenging totransform these natural-based compounds into products with high addedvalue.
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    Nickel alpha-Keto-beta-Diimine Initiators for Olefin Polymerization
    (WILEY-V C H VERLAG GMBH, 2009) Azoulay, Jason D.; Rojas, Rene S.; Serrano, Abigail V.; Ohtaki, Hisashi; Galland, Griselda B.; Wu, Guang; Bazan, Guillermo C.
    (Figure Presented) A new ligand-metal combination (see picture, Ni green, Br brown, N blue, O red, C gray) was designed to be cationic and to benefit from removal of electron density by the action of a Lewis acid on the ligand framework. In the presence of various activators, the resulting catalytic site is highly active for ethylene polymerization and capable of polymerizing α-olefins to high molecular weights. © 2009 Wiley-VCH Verlag GmbH & Co. KGaA.