Title:
Investigating Doped Mesoporous ZSM-5 for Cascade Catalysis
Investigating Doped Mesoporous ZSM-5 for Cascade Catalysis
Author(s)
Umo, David Ebung
Advisor(s)
Lively, Ryan P.
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Abstract
With the recent innovations and progress in the nanotechnology industry, a family of microporous catalysts and adsorbents known as zeolites were developed in the mid 20th century. Zeolites have a wide-range of applications in energy utilization, so scientists have been carrying out research on this material with a focus on solving the world’s global warming and energy crisis.
One Zeolite--commonly referred to as Zeolite Socony Mobil-5 (ZSM-5)--has shown a significant promise especially regarding potential applications in the petrochemical industry. The petrochemical industry is a major contributor towards the emission of greenhouse gases which cause global warming. The petrochemical industry also suffers from inefficient energy consumption in processes such as fractional distillation, hydrocracking etc. Scientists have carried out extensive research on zeolites’ application in post combustion CO2 capture to reduce the emission of CO2 and, in turn, reduce the effects of global warming. Similarly, scientists have also considered altering the acidity and basicity of the ZSM-5 to increase its catalytic efficiency for other industrial applications. Currently, the petrochemical Industry resorts to energetically intensive and inefficient processes to convert larger hydrocarbons to lighter, more valuable hydrocarbons and using ZSM-5 is a huge step towards solving this crisis.
This study plans on addressing this energy crisis by analyzing the catalytic efficiency of the ZSM-5 in carbon-carbon bond forming/breaking reactions like the aldol condensation reaction and the one-pot deacetlyation Knoevenagel cascade reaction. In this research, I will start by varying the acidity of the ZSM-5 by synthesizing various forms of the ZSM-5 and substituting silica atoms for heteroatoms like Tin, Aluminum and Boron. The acid sites act as the catalyst for the first step of the Knoevenagel reaction I will then introduce mesopores into the ZSM-5s through a mesopore forming agent known as Dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride (TPOAC). The mesopores will serve to allow grafting of a fixed amount of organo-silanes on the surface of the ZSM-5. The fixed amount of organo-silanes in turn serves as a basic functional group and ensures the basicity of each ZSM-5 is roughly equal. The basic sites act as the catalyst for the second step of the Knoevenagel reaction. The bi-functional catalyst (acidic and basic) will be analyzed using X-ray diffraction and Thermogravimetric analysis to ensure the desired structural goal is achieved. Subsequently, the various bi-functional catalytic ZSM-5s will be analyzed for their respective catalytic efficiency in the one-pot deacetylation knoevenagel cascade reaction with the non-catalyzed reaction serving as a control experiment. The results of each experiment will be analyzed using gas chromatography and the catalytic efficiency will be determined through the measured conversion of each reactant. I hypothesize that the Tin, Aluminum, Boron and All-Silica ZSM-5s will have a decreasing order of acidity and in turn a decreasing order of catalytic efficiency in the cascade reaction. This is because the density functional theory suggests the level of acidity to be in that order and the first step of the cascade reaction is the rate determining step and is also acid-catalyzed.
Conclusively, the results from this research could highlight the catalytic efficiency of the ZSM-5 and highlight its effectiveness in solving the world’s energy crisis. With the current move towards sustainable energy and energy efficiency globally, it is imperative that the Petrochemical Industry solves its energy crisis, to not be left behind in the energy race
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Date Issued
2017-05
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Text
Resource Subtype
Undergraduate Thesis