Further Insight into Carbohydrate Degradation and Dissolution Behavior during Kraft Cooking under Elevated Alkalinity without and in the Presence of Anthraquinone

M. Paananen, Tiina Liitiä, Herbert Sixta

    Research output: Contribution to journalArticleScientificpeer-review

    23 Citations (Scopus)

    Abstract

    The polysaccharide degradation and dissolution behavior during high liquor-to-wood ratio (200:1) kraft cooking of Scots pine wood meal was studied at high (1.55 M) and moderate (0.50 M) hydroxide ion concentrations at a constant sulfidity of 33%. Both alkalinity levels were studied in and without the presence of anthraquinone (AQ) (0.05, 0.15, and 0.25 g AQ/L). High alkalinity experiments without AQ at 130–160 °C clearly confirmed significant galactoglucomannan stabilization (in respect to lignin content) throughout initial and bulk delignification phases. Additionally, at high alkali compared to moderate alkali concentration, lower amounts of low molecular weight carboxylic acids originating from the degradation of carbohydrates were detected in spent black liquor. The presence of AQ provided significant hemicellulose stabilization against endwise degradation reactions, being more pronounced at moderate 0.50 M concentration than at 1.55 M hydroxyl ion concentration. In all cases, higher alkalinity promoted carbohydrate removal via dissolution, and the addition of AQ reduced the degradation of the dissolved carbohydrate fraction, thus further increasing the amount of dissolved polysaccharides found in black liquor.
    Original languageEnglish
    Pages (from-to)12777-12784
    Number of pages7
    JournalIndustrial & Engineering Chemistry Research
    Volume52
    Issue number36
    DOIs
    Publication statusPublished - 2013
    MoE publication typeA1 Journal article-refereed

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