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Document Type

Thesis - University Access Only

Award Date

2015

Degree Name

Master of Science (MS)

Department

Chemistry and Biochemistry

First Advisor

Cheng Zhang

Abstract

This thesis is divided into two parts: investigation of the Mitsunobu reaction of bulky phenols and aliphatic alcohols to improve yield, and studies of lignin dimer model compound synthesis and catalysts of lignin decomposition reaction for optimizing degradation reaction conditions to increase product yields of value-added chemicals. In the first part of this thesis, Mitsunobu reaction of sterically hindered phenols and primary alcohols was investigated in detail to reveal the reason for the low yield of product (30-40%) and a solution to the problem was proposed and tested. In Mitsunobu alkyl aryl etherification reactions, alkylation of hydrazinedicarboxylate- a Mitsunobu by-product could be a side reaction. For essentially all Mitsunobu reactions in the literature, this side reaction is not a notable problem and good yields can be obtained with a wide range of solvents used. However, for the reactions of sterically hindered phenols and primary alcohols, this side reaction can significantly decrease the product yields. To suppress the side reaction and improve the product yields, solvent effect was studied and it was found that the yields are improved by using a weaker solvent, such as diethyl ether, instead of THF. In the second part of this thesis, synthesis of a lignin model compound (a dimer) and xiii study of its hydrothermal decomposition were conducted as an effort to explore effective methods to convert lignin, the largest renewable source of aromatics, into valuable chemicals. Since -O-4 bond is the predominant linkage in lignin, selective cleavage of this bond is sufficient to breakdown lignin into monomers and low oligomers which can be used directly for synthesis of certain materials such as adhesive resins. Lignin model compound with -O-4 bond has been synthesized through a four-step reaction scheme and the dimer decomposition using various catalysts has been studied. It is found that repolymerization (or condensation) happens at a relatively low temperature (120 oC) with or without a catalyst. This work points out the need to develop methods to suppress condensation reactions.

Library of Congress Subject Headings

Chemical reactions
Phenols
Lignin
Dimers
Organic compounds -- Synthesis
Decomposition (Chemistry)

Description

Includes bibliographical references (pages 72-82)

Format

application/pdf

Number of Pages

95

Publisher

South Dakota State University

Rights

In Copyright - Educational Use Permitted
http://rightsstatements.org/vocab/InC-EDU/1.0/

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