Date of Award
Doctor of Philosophy (PhD)
Materials are a vital part of human life, as such, it is important that the precursors to these materials are sustainable. Currently, these precursors are synthesized by the oxidation of petroleum-derived hydrocarbons. Petroleum is not sustainable and is feared to deplete soon. Derivatizing the currently available biomass-based building blocks will diversify and increase the number of precursors for materials and gradually reduce our reliance on petrochemicals.The carboxylic dianhydride, CBDAN-1, a potential biomass-derived precursor for material synthesis, was synthesized from the photodimerization of maleic anhydride or the dehydration of CBTA-1. CBTA-1 was synthesized from the photodimerization of maleic and fumaric acids using UV-C (254 nm). Other carboxylic dianhydrides; CBDAN-3, CBDAN-4, and CBDAN-5, were synthesized from the photodimerization of citraconic anhydride and 2,3-dimethylmaleic anhydride respectively using black light. The CBDANs showed good thermal stability, making them desirable to be used as precursors for material synthesis. To demonstrate the versatility of CBDANs, CBDAN-1 was used to synthesize eight cyclobutane-containing diacids using amine, alcohol, or Grignard reagent as nucleophiles. The TGA of the synthesized diacids showed that these molecules were thermally stable enough to be incorporated as precursors in polymer synthesis. A carboxylic dianhydride (CBDAN-2), synthesized from maleic anhydride and benzene was used to synthesize polyimides with 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and hexane-1,6-diamine. The polyimides showed desirable properties such as high Td. Metal-organic materials synthesized from the polytopic ligand CBTA-2, a derivative of CBDAN-2, showed good thermal and interesting thermochromic behavior. CBDAN-2 was also used to synthesize two dicarboxylic acids which can be used in the synthesis of polyesters. Furanones share several features in common with the furanediones. The latter has been shown to be a versatile precursor in material synthesis. We, therefore, hypothesized that dimers of furanones could also be explored in the synthesis of precursors to materials. Cyclobutane-containing dilactones (CBDL) were obtained from the photodimerization of 2(5H)-furanone, 3-methyl-2(5H)-furanone, and 5-hydroxy-2(5H)-furanone under UV-C (254 nm). The thermal stability of these dilactones showed that they are stable enough to be incorporated into polymers. In conclusion, in this dissertation, the synthesis and characterization of several cyclobutane-containing diacids, dianhydrides, and dilactones have been shown. Also, one of the synthesized dianhydrides was used to synthesize polyimides and MOMs. All these monomers and materials were synthesized from potential biomass-derived precursors using simple, efficient, and eco-friendly methods.
Nkemngong, Dominic Nkafu, "Exploring [2+2] Photoreaction To Synthesize Cyclobutane Di- And Tetracarboxylic Acid Building Blocks From Biomass-Derived Precursors" (2022). Theses and Dissertations. 4364.
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