Unconventional RISS catalysts for biobased hydrogen and renewable chemicals

Description

In light of the need for major global transformations to achieve sustainable development goals, the use of biodegradable fatty acid methyl esters (FAMEs) as renewable sources of organic carbon derived vegetable oils, animal fat, waste cooking oils and algae, has valuably contributed to answer to the increasing needs for fuels and chemicals, and reduce the carbon footprint. The billions of euros/dollars value market of fatty acid methyl esters (FAME) covers lubricants, solvents, polymers production, but its greatest market volume is biodiesel for terrestrial/marine transport, generators, domestic heating, industrial boilers. Hence, FAMEs upgrading is of great interest to the chemical industry at national and international levels. The upgrading of the FAMEs by catalytic hydrogenation or catalytic epoxidation can valuably lead to improved properties such as, oxidation stability (a fundamental requirement for storage, quality and performance of FAMEs and derived products) and cold-flow properties (requirement for biofuels applications in low-temperature geographic regions). Moreover, upgrading FAMEs to epoxidized FAMEs (EFAMEs) has opened markets in various applications sectors such as, plasticizers, epoxy resins, lubricants and other with potential increasing. Catalytic hydrogenation of FAMEs (FAMEHD) has involved the use of expensive noble metal catalysts and high-pressure hydrogen and temperatures. However, processes using high pressure of H2 pose safety problems and high costs associated with storage, transport and operation. Sustainable technologies with more moderate and safer operating conditions require the use of renewable, biodegradable and non-flammable hydrogen donors. For this purpose, one of the most attractive hydrogen donors is formic acid, since it fulfils all the above requirements and also has the advantage of being produced in the conversion of lignocellulosic biomass in biorefineries, contributing to completely bio-based technologies. This strategy becomes even more relevant and attractive if the dehydrogenation of FA to hydrogen (FADH) is integrated with FAMEHD. This process intensification strategy has further important advantages such as reducing energy consumption, costs and carbon footprint. In the search for non-noble metal catalysts, Mo-based catalysts proved effective for FADH, as well as for FAMEHD (using H2), but no studies were reported for Mo-catalysed integrated FADH/FAMEHD, which will be innovatively addressed in this project through the design of new molybdenum complexes possessing adequate catalytic properties. Besides the upgrading of FAMEs via hydrogenation, this project contributes to FAMEs upgrading via epoxidation to EFAMEs with wide applications profiles, for which new Mo-based oxide catalysts will be developed. The two FAMEs upgrading strategies explored in this project – hydrogenation and epoxidation - will contribute to decreased unsaturation degree of FAMEs, imparting higher stability. Moreover, to reach higher sustainability, unconventional reaction induced self-separating catalysts (RISS) catalysts will be explored. RISS catalysts undergo self and reversible structural deconstruction-reconstruction, featuring the best sides of homogeneous catalysis and heterogeneous catalysis, which is especially beneficial for reactions of the upgrading of bulky molecules such as FAMEs, e.g., by eliminating internal diffusional issues. However, there is little or no research and development on the target processes using RISS catalysts. Only one RISS catalyst was reported for FADH, which was a noble metal catalyst, and no studies were reported for FAMEHD or integrated FADH/FAMEHD. On the other hand, only two RISS catalysts were reported for FAMEs epoxidation; a Mo-based polyoxometalate (POM) and a Mo-based organic-inorganic hybrid polymer. This project aims at FAMEs upgrading via the two different strategies - hydrogenation and epoxidation - using RISS Mo catalysts. Hence, the activities include the synthesis and characterization of new, adequate Mo catalysts and developing sustainable catalytic upgrading strategies of FAMEs. For this, the research team has complementary skills in synthesis and characterization of Mo compounds, RISS catalysis, epoxidation catalysis, chemical biomass valorization and integrate hydrogenation of biobased products using FADH; the project includes job offers for young students. Two consultants - one with expertise in organometallic and inorganic chemistry, and the other with expertise in catalysis and chemical reaction engineering - will provide expert advice.