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Showing 1 to 20 of 197 for “"Hydroxyl Groups"”.
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Applications for the activation of hydroxyl groups to nucleophilic attack
… the applications of the activation of hydroxyl groups to nucleophilic attack within three key areas: Cyclic five-membered thionocarbamates bearing a N-Boc group undergo ring opening reactions at the 5-C with soft nucleophiles such as thiophenolate, pyridine-2-thiolate and potassium …
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The kinetics of hydrogen exchange between hydroxyl groups of alcohols
Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1960
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The effect of supercritical water on crude glycerin solution
… a better understanding of how the functional groups of different hydrocarbon molecules react when exposed to supercritical water, experiments were also conducted to determine the effect of hydroxyl groups on hydrocarbons in supercritical water. These experiments used isopropanol, propylene …
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Benzophenone Derivatives of Hexitols in tthe Carbohydrate Series
It is known that hydroxyl groups in sugars have been blocked by various methods to facilitate analytical, synthetic and structural problems. Benzoates, methyl groups, acetal groups, etc. have been used for this purpose. |For example, compounds of glucosides with aromatic aldehydes were synthesized …
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Studies of Some Catalytic Properties of Zeolites
… rearrangement have been identified as surface hydroxyl groups located at specific sites within the zeolitic lattice. The most efficient catalysts for the rearrangement, therefore, are the decationated or hydrogen zeolites. The interaction of cyclohexanone oxime with zeolites containing no …
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Selective dehydration of polyols over solid acids and metal-acid bifunctional catalysts: Towards a catalytic toolbox for rational catalyst design
… which consist of a carbon backbone and multiple hydroxyl groups. Most polyols are derived from biorenewable sources, ranging from glycerol, which comes from triglycerides, up to 6-carbon sugar alcoohols. Selective removal of these hydroxyl groups is desired, either in the form of eliminating …
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Síntese de nanopartículas de magnetita via decomposição térmica em meio não-aquoso
… magnetic behavior. Finally, the introduction of hydroxyl groups on the nanoparticles surface was analyzed besides its employment in the polymer production with OH radicals. The obtained materials were characterized by XRD, DLS, VSM, TEM, TG and DSC analyses. The results for the magnetite …
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The effect of the positions and molecular weight of hydrophilic functional groups of surfactants on gas absorption rates
… weight of surfactant hydrophilic functional groups on the rate of gas absorption. A quiescent unsteady-state absorption apparatus was used with carbon dioxide and water as the absorption system. Three surfactants with hydroxyl groups were selected for study, namely, n-octanol, 4-octanol and …
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Time Dependent Uptake of Volatile Organic Compounds on Silica and the Observation and Quantification of Ambient Sesquiterpenes in Virginia
… compounds for a silica surface composed of hydroxyl groups and bridging oxygen species. Results for benzene derivatives show an enhancement of the initial γ value of all functionalized compounds relative to benzene, with this initial value influenced by both the dipole and volatility of a …
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The Preparation, Functionalization and Biomedical Applications of Carbonaceous Nanomaterials
… with poly(ethylene glycol) (PEG) and hydroxyl groups (Gd₃N@C₈₀[DiPEG(OH)ₓ]). The length of the PEG chain was tuned by changing the molecular weight of the PEG from 350 to 5000. The 1H magnetic resonance relaxivities of the materials were studied at 0.35 T, 2.4 T and 9.4 T. Their …
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INVESTIGATION OF PROCESSING-STRUCTURE-PROPERTY RELATIONS IN VAPOR PHASE MODIFIED CELLULOSIC MATERIALS
… The cellulose molecule has a high density of hydroxyl groups, which causes strong intra-/inter- fiber hydrogen bonding. These abundant hydroxyl groups make cellulose super-hydrophilic and difficult to disperse or dissolve in nonpolar organic solvents or polymers. The traditional methods to …
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Solubilisation properties of phosphatidylcholine
… and on the number and acidity of its free hydroxyl groups. Enthalpy and entropy of solubilisation were determined for glucose and the results are consistent with an interaction mechanism involving hydrogen bonding via the free hydroxyl groups. Cholesterol, when present as a co-solute, …
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Surface modification of titanium dioxide and synthesis of non- electroactive coatings by electrochemical polymerization
… the nature of the reactivity of surface hydroxyl groups towards different <u>silanes</u>, a surface IR study was carried out on TiO₂ powders. The powder (TiO₂) was pressed into a pellet and subjected to reactions with various silanes under different reaction conditions. All of these …
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ΚΙΝΗΤΙΚΗ ΜΕΛΕΤΗ ΚΑΙ ΑΝΑΛΥΤΙΚΕΣ ΕΦΑΡΜΟΓΕΣ ΕΝΖΥΜΙΚΩΝ ΣΥΣΤΗΜΑΤΩΝ ΓΙΑ ΤΟΝ ΠΡΟΣΔΙΟΡΙΣΜΟ ΧΟΛΙΚΩΝ ΟΞΕΩΝ ΣΕ ΒΙΟΛΟΓΙΚΑ ΥΓΡΑ
… ARE BASED ON THE SPECIFIC OXIDATION OF THEIR HYDROXYL GROUPS BY NICOTINAMIDE ADENINE DINUCLEOTIDE (B-NAD+) OR BY B-NADP+ IN THE PRESENCE OF HYDROXYSTEROID DEHYDROGENASES (HSD) AND ON THE FLUORIMETRIC MONITORING OF THE PRODUCED NADH OR NADPH. THE PRESENT DISSERTATION CONTRIBUTES TO THE …
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Novel derivatives of sporopollenin for potential applications in solid phase organic synthesis and drug delivery
… investigation into the types of functional groups present on the sporopollenin surface was undertaken to explain the types of functionalities present on sporopollenin and examine their reactivity. The objective was to assess the potential of sporopollenin for use as a solid phase support for …
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Steroid metabolism in the human gut by microbial hydroxysteroid dehydrogenases
… enzyme activity is the oxidoreduction of steroid hydroxyl groups by hydroxysteroid dehydrogenases (HSDHs). Pairs of HSDHs can reversibly epimerize α-hydroxyl groups through an oxo-intermediate to β-hydroxyl groups. These small modifications of steroid structure often greatly influence their …
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Biofuels from lignin and novel biodiesel analysis
… for the determination of the various types of hydroxyl groups present in biodiesel production streams. In the first study, the use of 2-chloro-4,4,5,5-tetramethyl-1,3,2-dioxaphospholane as a phosphitylation reagent for quantitative ³¹P-NMR analysis of the hydroxyl groups in biodiesel process …
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The Influence of Incorporated Cholesterol Auto-Oxides Upon The Permeability and Fluidity of Multilamellar Vesicles (Oxidized Sterols)
… determine whether or not the polar substituent groups altered the orientation of the sterol molecule within the membrane bilayer. Using cholesterol incorporation into multilamellar vesicles of egg yolk lecithin: dicetylphosphate as a basis for comparison, the glucose permeability of the …
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Synthesis of Resveratrol Ester Derivatives
… that were synthesized have converted one of the hydroxyl groups on resveratrol to an ether with a methylene chain terminated by a carboxylic acid. By varying the lengths of the methylene chain we varied the water solubility of the resveratrol derivative. This brought the research closer to the …
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Synthesis of polymers and copolymers of lactide through titanium initators
… L-Iactide using Ti(O-i-Pr)4 as an initiator and hydroxyl-terminated PEG's with different numbers of hydroxyl groups as co-initiators both in solution and solventless media. These all-in-one polymersations yielded the synthesis of both lactide homopolymer and lactide/PEG block copolymer. In order …
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