Presentation Title

Deoxydehydration Reaction Catalyzed by Dioxomolybdenum Complexes of Salan Ligands

Faculty Mentor

Dr. Alex John

Start Date

17-11-2018 9:30 AM

End Date

17-11-2018 9:45 AM

Location

C327

Session

Oral 2

Type of Presentation

Oral Talk

Subject Area

physical_mathematical_sciences

Abstract

The world’s material and energy needs are currently met primarily through the utilization of fossil resources. Petrochemicals, for example, are used as fuel and utilized in the synthesis of various chemicals and materials. Although this method has proven to be the most efficient and effective, we cannot rely heavily on it, especially long term, because fossil fuels are finite and associated processes are environmentally harmful. Therefore, a transition from fossil fuels to other renewable resources is a necessity. In this study, we investigate the possibility of using biomass as a renewable resource that ultimately shares similar characteristics to petroleum. However, biomass such as lignocellulose, is highly functionalized (oxygenated), while petroleum are mostly hydrocarbons in nature. We perform a couple of reduction reactions to reduce this highly-functionalized attribute in biomass: Deoxydehydration (DODH) and dehydration reactions, which converts diols and alcohols into olefins. The best DODH catalysts discovered so far involve the rare transition metal, rhenium. This metal has shown to provide the best yields; however, it is absurdly expensive and scarce. On the other hand, the transition metal molybdenum is more abundant, cheaper and similar to rhenium, but with reduced yields. By supporting the molybdenum catalyst over salan ligands, we explore the potential of using this more practical molybdenum catalyst in the facilitation of DODH and dehydration reactions. More specifically, we want to see how changing the ligand backbone from (N,N’-H2)LMoO2 to (N,N’-Me2)LMoO2 in these complexes affects catalytic efficiency.

Summary of research results to be presented

We found that by changing the salan ligand backbone from (N,N’-H2)LMoO2 to (N,N’-Me2)LMoO2,, the catalytic activity decreased substantially. We synthesized and tested two molybdenum catalysts of salan ligands with identical backbones ((N,N’-Me2)LMoO2) on their ability to reduce styrene glycol to styrene and found that the % yield of styrene decreased from 40-60% to less than 5%. The manipulation of the complex’s phenyl substituents also had no effect on catalytic activity. Overall, the change from (N,N’-H2)LMoO2 to (N,N’-Me2)LMoO2 ultimately killed the catalyst. After considering the results obtained, we think that by limiting a catalysts flexibility (changing from (N,N’-H2)LMoO2 to (N,N’-Me2)LMoO2), the molybdenum catalyst is unable to effectively and efficiently facilitate the DODH and dehydration reduction reactions.

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Nov 17th, 9:30 AM Nov 17th, 9:45 AM

Deoxydehydration Reaction Catalyzed by Dioxomolybdenum Complexes of Salan Ligands

C327

The world’s material and energy needs are currently met primarily through the utilization of fossil resources. Petrochemicals, for example, are used as fuel and utilized in the synthesis of various chemicals and materials. Although this method has proven to be the most efficient and effective, we cannot rely heavily on it, especially long term, because fossil fuels are finite and associated processes are environmentally harmful. Therefore, a transition from fossil fuels to other renewable resources is a necessity. In this study, we investigate the possibility of using biomass as a renewable resource that ultimately shares similar characteristics to petroleum. However, biomass such as lignocellulose, is highly functionalized (oxygenated), while petroleum are mostly hydrocarbons in nature. We perform a couple of reduction reactions to reduce this highly-functionalized attribute in biomass: Deoxydehydration (DODH) and dehydration reactions, which converts diols and alcohols into olefins. The best DODH catalysts discovered so far involve the rare transition metal, rhenium. This metal has shown to provide the best yields; however, it is absurdly expensive and scarce. On the other hand, the transition metal molybdenum is more abundant, cheaper and similar to rhenium, but with reduced yields. By supporting the molybdenum catalyst over salan ligands, we explore the potential of using this more practical molybdenum catalyst in the facilitation of DODH and dehydration reactions. More specifically, we want to see how changing the ligand backbone from (N,N’-H2)LMoO2 to (N,N’-Me2)LMoO2 in these complexes affects catalytic efficiency.