Minimizing the effect of undesirable reactions in ECF bleaching
-
Dominique Lachenal
,
Delphine Delmas
Abstract
One undesirable reaction during ECF bleaching is the formation of resistant quinones during the oxidation of lignin phenolic rings by ClO2. Occurrence of this side reaction was confirmed by the implementation of a new in situ method for quinone detection. It is based on the selective reaction of free-phenol groups in pulp with ClO2 at low temperature (0°C) and on the reduction of quinones into free phenols by sodium dithionite. Although not absolutely quantitative, it gives valuable information on the quinone content without any need of lignin extraction. It is proposed to apply a hydrogen peroxide treatment after each ClO2 (D) stage to solve this problem. Another undesirable reaction is the consumption of ClO2 by the muconic acid type structures which are the primary oxidation products of lignin during a D stage. Experiments with Z,Z-2, 5-dimethyl muconic acid, a model for lignin oxidized units, indicated that this reaction is most probable. Although phenolic moieties in lignin are more reactive than the muconic acid structures, the use of high ClO2 charges respective to lignin may favour its consumption by the muconic acid structures. One solution to this problem is to apply lower charges of ClO2 in each D treatment. The relevance of these findings was demonstrated by the high efficiency of (DEP)(DEP) sequences, where DEP stands for a ClO2 stage at low charge of chlorine dioxide immediately followed by an alkaline hydrogen peroxide treatment.
©2012 by Walter de Gruyter Berlin Boston
Artikel in diesem Heft
- Original Papers
- Novel paper sizing agents based on renewables. Part 5: characterization of maleated oleates by ozonolysis
- Polythiophene-cellulose composites: synthesis, optical properties and homogeneous oxidative co-polymerization
- The influence of extended mercerization on some properties of carboxymethyl cellulose (CMC)
- Minimizing the effect of undesirable reactions in ECF bleaching
- A rheological description of the water vapour sorption kinetics behaviour of wood invoking a model using a canonical assembly of Kelvin-Voigt elements and a possible link with sorption hysteresis
- Changes in chemistry, color, dimensional stability and fungal resistance of Pinus radiata D. Don wood with oil heat-treatment
- Improvement of dimensional stability of wood via combination treatment: swelling with maleic anhydride and grafting with glycidyl methacrylate and methyl methacrylate
- Synthesis and properties of resol-type phenol-formaldehyde resins prepared from H2SO4- and HCl-catalyzed phenol-liquefied Cryptomeria japonica wood
- Tack and shear strength of hybrid adhesive systems made of phenol-formaldehyde, dextrin and fish glue, and acrylic pressure-sensitive adhesive
- Properties of thermally modified medium-density fibreboards
- Carbonaceous structural changes of wood induced by microwave irradiation
- Development of DNA-based methods to identify CITES-protected timber species: a case study in the Meliaceae family
- Fungal biodegradation of genetically modified and lignin-altered quaking aspen (Populus tremuloides Michx.)
- The effect of fiber dimensions on fiber network activation and tensile strength
- Preparation of chitosan oligomers and characterization: their antifungal activities and decay resistance
- Cellular and topochemical characteristics of secondary changes in bark tissues of beech (Fagus sylvatica)
- Short Notes
- A study by X-ray photoelectron spectroscopy (XPS) of the chemistry of the surface of Scots pine (Pinus sylvestris L.) modified by friction
- Comparative termite resistance of 12 Malaysian timber species in laboratory tests
- Meetings
- 10.1515/HF.2011.185
Artikel in diesem Heft
- Original Papers
- Novel paper sizing agents based on renewables. Part 5: characterization of maleated oleates by ozonolysis
- Polythiophene-cellulose composites: synthesis, optical properties and homogeneous oxidative co-polymerization
- The influence of extended mercerization on some properties of carboxymethyl cellulose (CMC)
- Minimizing the effect of undesirable reactions in ECF bleaching
- A rheological description of the water vapour sorption kinetics behaviour of wood invoking a model using a canonical assembly of Kelvin-Voigt elements and a possible link with sorption hysteresis
- Changes in chemistry, color, dimensional stability and fungal resistance of Pinus radiata D. Don wood with oil heat-treatment
- Improvement of dimensional stability of wood via combination treatment: swelling with maleic anhydride and grafting with glycidyl methacrylate and methyl methacrylate
- Synthesis and properties of resol-type phenol-formaldehyde resins prepared from H2SO4- and HCl-catalyzed phenol-liquefied Cryptomeria japonica wood
- Tack and shear strength of hybrid adhesive systems made of phenol-formaldehyde, dextrin and fish glue, and acrylic pressure-sensitive adhesive
- Properties of thermally modified medium-density fibreboards
- Carbonaceous structural changes of wood induced by microwave irradiation
- Development of DNA-based methods to identify CITES-protected timber species: a case study in the Meliaceae family
- Fungal biodegradation of genetically modified and lignin-altered quaking aspen (Populus tremuloides Michx.)
- The effect of fiber dimensions on fiber network activation and tensile strength
- Preparation of chitosan oligomers and characterization: their antifungal activities and decay resistance
- Cellular and topochemical characteristics of secondary changes in bark tissues of beech (Fagus sylvatica)
- Short Notes
- A study by X-ray photoelectron spectroscopy (XPS) of the chemistry of the surface of Scots pine (Pinus sylvestris L.) modified by friction
- Comparative termite resistance of 12 Malaysian timber species in laboratory tests
- Meetings
- 10.1515/HF.2011.185
