Sökning: "hydroxyl groups"

Visar resultat 1 - 5 av 123 avhandlingar innehållade orden hydroxyl groups.

  1. 1. Light-Induced Yellowing of High-Yield Pulps. The Effect of Acetylation

    Författare :Magnus Paulsson; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; yellowing; mechanical properties; hydroxyl groups; phenolic groups; paper; high-yield pulps; chromophores; model compounds; acetylation; inhibition;

    Sammanfattning : This thesis is a contribution to the understanding of the mechanism of photoyellowing of high-yield pulps. It also gives some general information about the reactivity of different functional groups in lignin towards acetic anhydride. LÄS MER

  3. 2. Structure, Bonding and Chemistry of Water and Hydroxyl on Transition Metal Surfaces

    Författare :Klas Andersson; Anders Nilsson; Falko Netzer; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; core-level spectroscopy; surface chemistry; water; hydroxyl; metal surfaces; adsorption; structure; hydrogen bonding; Chemical physics; Kemisk fysik;

    Sammanfattning : The structure, bonding and chemistry of water and hydroxyl on metal surfaces are presented. Synchrotron based x-ray photoelectron- and x-ray absorption spectroscopy along with density functional theory calculations mainly form the basis of the results. LÄS MER

  4. 3. Synthesis and chemical modification of some carbohydrates containing amino groups

    Författare :Jan Arnarp; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : The alkylation with alkyl trifluoromethanesulfonates of hydroxyl groups in carbohydrates, containing base- or acid-labile substituents, has been examined. The reagent simultaneously transforms acetamindo groups to N-methylamino groups. Synthesis and nitrous acid deamination of methyl 4-amino-4-deoxy-β-L-arabinopyranoside has been performed. LÄS MER

  5. 4. Development and characterisation of protecting groups that enhance the solubility of synthetic peptides : Methods to improve the aqueous solubility of hydrophobic peptides

    Författare :Karolina Wahlström; Anders Undén; Fernando Albericio; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Solid phase peptide synthesis; Fmoc chemistry; solubility problems; tryptophan; tyrosine; Nmec; Nmbu; Bioorganic chemistry; Bioorganisk kemi; Neurochemistry and Molecular Neurobiology; neurokemi med molekylär neurobiologi;

    Sammanfattning : Chemical synthesis of peptides is generally performed by solid phase peptide synthesis (SPPS). Although SPPS is a rapid and convenient method to prepare peptides, the major methodological problem in SPPS is related to solvation/solubility. LÄS MER

  7. 5. Cellulose-water interaction: a spectroscopic study

    Författare :Erik L Lindh; István Furó; Lennart Salmén; Lisbeth G Thygesen; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; cellulose; water; hydrogen exchange; deuterium; NMR spectroscopy; FT-IR spectroscopy; Kemi; Chemistry;

    Sammanfattning : The human society of today has a significantly negative impact on the environment and needs to change its way of living towards a more sustainable path if to continue to live on a healthy planet. One path is believed to be an increased usage of naturally degradable and renewable raw materials and, therefore, attention has been focused on the highly abundant biopolymer cellulose. LÄS MER