Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 435 for “"lignin"”.
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Hydroxypropylation of lignin and lignin-like model compounds
… reaction of propylene oxide and Kraft lignin with various catalysts, catalyst concentrations, at several temperature levels were studied. The reaction rate of propylene oxide was estimated from the pressure vs time diagram of the reaction and the copolymerization extent was evaluated on …
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Lignin valorization
The topic of this project is the use of lignin as alternative source of aromatic building blocks and oligomers to fossil feedstocks. Lignin is known as the most abundant aromatic polymer in nature and is isolated from the lignocellulosic component of plants by different possible extraction …
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Microbial transformation of lignin
… treatment. This work looks at the concept of lignin bioprocessing from the vantage point of a biochemical engineer. Coriolus versicolor, Phanerochaete chrysosporium and Sporotrichum pulverulentum, which being white-rot fungi are traditional lignin degraders, were found to be much less …
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Bimetallic Catalyst for Lignin Depolymerization
… products with reduced greenhouse gas emissions. Lignin is the second abundant biopolymer source in nature and is found almost everywhere. Since the 1950’s, there have been reports of lignin depolymerization research to develop valorization technologies that convert lignin in energy, fuels, and …
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Synthetic, Sulfated, Lignin-Based Anticoagulants
… synthesized low molecular weight lignin polymers have been previously found to be potent inhibitors of a number of serine proteases via allosteric mechanisms targeting heparin binding sites. Herein, we describe the creation of synthetic sulfated β-O4 lignin (SbO4L) polymer, which …
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Model pathways in lignin thermolysis
Thesis (Sc.D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1981.
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Star-like macromers from lignin
… macromers were prepared from hydroxypropyl lignin by reaction with propylene oxide. The average number of arms per macromer was controlled by partial capping with diethylsulfate, and the average arm length by the degree of chain extension with propylene oxide. Six methods of analysis were …
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The chlorination of sulfate lignin
The study of lignin with the aim of correlating data, which may lead to a greeter utilization of this wood waste product, has been the subject of investigations since 1838. Previous investigations by Othmer, Harris, Sherrard and others have indicated that chlorinated lignin had potential value as a …
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Lignin biodegradation: reduced oxygen species
Lignin degradation, is quite common in nature and is an important link in the natural carbon cycle. A large variety of microorganisms are know to degrade lignin in nature as well as in contrived fermentation systems. White-rot and soft-rot fungi, as well as Actinomycetes, are apparently the most …
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Biochemical Evaluation of Lignin-like Molecules
… designed sulfated low molecular weight lignin (LMWL) like biomacromolecules, which were found to be direct inhibitors of thrombin and factor Xa, acting through a unique exosite-2 mediated process. To elucidate the structural basis of this mechanism, we studied unsulfated and size …
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Plasticized lignin-PVC blends for flooring
… PVC in the formulation of flooring materials by lignin, an abundant and renewable natural polymer. The utilization of lignin, is aimed to develop more cost-effective flooring materials with appreciable mechanical properties, to decrease their susceptibility to microbial attack, to decrease the …
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Catalytic Upgrading of Lignin From Biomass
… success of biorefineries is the utilization of lignin, an oxygenated aromatic polymer making up 15-30% of all lignocellulose. Effective and economical lignin upgrading techniques have remained elusive, largely due to the complex structure and reactivity of lignin during processing. Broadly, my …
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Studies on lignin biosynthesis and structure
… (21 days) and subsequent isolation of the lignin from the root tissue as its acetal derivative demonstrated the incorporation of the labelled feru1ic acid into the lignin component of the tissue. Through sim1lar administrations of (1-¹³C, 2-¹³C and 3-¹³C) ferul1c acid and subsequent …
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Synthesis and properties of lignin epoxide
A lignin epoxide resin was synthesized and characterized. The epoxidation reaction was studied by reacting hydroxypropylated guaiacol (a lignin-like model compound) and epichlorohydrin using a catalyst system of potassium hydroxide and a phase transfer catalyst in toluene. The parameters studied …
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Biochemical Lignin Related Processes in Landfills
… the study the solubilization and degradation of lignin in paper exposed to these bioreactor landfill conditions are explored. The solubility of the lignin in paper was observed at different temperatures and over 27 weeks at 55°C and the anaerobic bioconversion of office paper, cardboard and Kraft …
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About the gel structure of lignin
… treatments of increasing severity, and the lignin sol fractions were analyzed with regard to chemical structure and molecular architecture. Treatments with 0.2 N HCL in 90% aqueous dioxane ranged between 12 hr. at room temperature and 8 hrs. at reflux. The analysis of the dissolved lignin …
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Studies on lignin biosynthesis and biodegradation
… patterns of specific carbon atoms in woody plant lignin have been identified in situ. This was accomplished by administering and incorporating into the lignin fraction of Leucaena leucocephala, a tropical hardwood, ferulic acid enriched with ¹³C at either the 1-, 2-, or 3-C atom of the side chain. …
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Biofuels from lignin and novel biodiesel analysis
… key challenge in this process is the recovery of lignin from process streams such that it can be utilized in a variety of innovative green chemistry processes The first study examines the fundamental chemical structure of LignoBoost derived lignin recovered from Kraft pulping streams using an acid …
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Modeling Solvent Extraction of Lignin from Hardwoods
… the observed behavior of solvent extraction of lignin from hardwoods by adapting the framework of the FLASHCHAIN theory (Niksa and Kerstein, 1991; Niksa, 2017). A constitution submodel specifies distributions of molecular weight and reactive sites for native lignin. The model simulates …
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Intermediate compounds in the synthesis of lignin
<p>The synthesis of a keto-aldehyde from salicylaldehyde and benzaldehyde was attempted. The first step was to protect the carbonyl with a non-reactive group.</p><p>The bisulfite addition product and the 2,4-dinitrophenylhydrazone of salicylaldehyde were prepared. The methyl acetal, the sodium …
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