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 Forest Products
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Puu-19.3000 Chemistry of Pulping and Bleaching (5 cr)

  
   

 

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    Lectures

    		  

    Schedule

    Course during the spring term 2008

    13.3.-5.5.

    Monday 10-12 at A,
    Wednesday 8-10 at A and
    Thursday 8-10 at A

    You can get the required username and password for the lecture material from
    Anne Vikkula (anne.vikkula(a)tkk.fi).

    Time
    Lecturer
    Material
    Content
    Thu 13.3.
    		Tapani Vuorinen
    		Introduction.
       
    		PULPING CHEMISTRY
    Mon 17.3.
    		 Tapani Vuorinen Lignin reactions in the bulk delignification. Nucleophilic substitution. Nucleophilicity. Depolymerization vs. demethylation.
    Wed 19.3
    		 Tapani Vuorinen Lignin reactions in the initial delignification.Concurrent reactions
    Thu 27.3.
    		 Tapani Vuorinen Reactions of hexenuronic acid groups in pulping. Formation and degradation. Elimination reactions. Effect of ionic strength on the rate of reaction. Sequential reactions.
    Mon 31.3.
    		 Tapani Vuorinen Alkali-catalyzed degradation of carbohydrates. Endwise peeling and stopping reactions.
    Wed 2.4.
    		 Tapani Vuorinen Hydrolysis of cell wall polysaccharides. Cleavage of acetyl groups. Acid- and alkaline catalyzed hydrolysis of glycosidic linkages.
    Thu 3.4.
    		Tapani Vuorinen Lignin-carbohydrate linkages in native wood and kraft pulp. Formation of covalently bonded linkages between lignin and polysaccharides, and the effect on pulping and bleaching.
    Mon 7.4.
    		 Tapani Vuorinen Extractives in wood and their behaviour in pulping and bleaching.
    Wed 9.4. Tapani Vuorinen Chromophores and reactive structures of residual lignin. Chromophoric structures in native wood and kraft pulp.
    		 
    		BLEACHING CHEMISTRY
    Thu 10.4.
    		Tapani Vuorinen Classification of bleaching chemicals. Electrophiles, nucleophiles and radicals.
    Mon 14.4. Tapani Vuorinen Selective hydrolysis of hexenuronic acid groups. Kinetic description. Effects of hexenuronic acid concentration, selectivity, and viscosity. Products of hydrolysis.
    Wed 16.4.
    		 Tapani Vuorinen

    L12

    Oxygen delignification. Formation of phenoxyl radicals. Reactivity of p-phenols and m-phenols. Formation of hydrogen peroxide in oxygen bleaching. Selectivity.

    Thu 17.4.

    Tapani Vuorinen

    L13

    Transition metal ion catalyzed decomposition of hydrogen peroxide. Catalytic cycle and pH dependency of the reaction. Effects of oxygen pressure, ionic strength, and reducing sugars on reaction kinetics.

    Mon 21.4.

    Tapani Vuorinen

    L14

    Peracetic acid bleaching. Competing electrophilic and nucleophilic reactions of peracids. Effects of HexA and pH on selectivity.

    Wed 23.4.

    Tapani Vuorinen

    Chlorine dioxide bleaching. Reactions of chlorine dioxide. Formation of chlorite. Decomposition of chlorite. Effect of reaction conditions on relative rates of chlorination and hydroxylation.

    Thu 24.4.

    		 Tapani Vuorinen

    L16

    Ozone bleaching. Diffusion controlled bleaching. Surface selectivity. Shrinking core model. Reactions of ozone with lignin, carbohydrates and HexA.
    Mon 28.4. Tapani Vuorinen

    L17

    Donnan phenomenon in bleaching. Catalytic bleaching. Properties of fibres and fibre engineering.
    Mon 5.5. Tapani Vuorinen

    L18

     

    Donnan phenomenon and catalytic bleaching.

     

     

     
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