Documents disponibles écrits par cet auteur

Kinetics of aldehyde oxidation by chlorous acid / Tuula Lehtimaa in Industrial & engineering chemistry research, Vol. 49 N° 6 (Mars 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 6 (Mars 2010) . - pp. 2688–2693 Titre : Kinetics of aldehyde oxidation by chlorous acid Type de document : texte imprimé Auteurs : Tuula Lehtimaa, Auteur ; Susanna Kuitunen, Auteur ; Ville Tarvo, Auteur Année de publication : 2010 Article en page(s) : pp. 2688–2693 Note générale : industrial Chemistry Langues : Anglais (eng) Mots-clés : Kinetics  Aldehyde  Oxidation  Chlorous  Acid Résumé : Chlorous acid is known to react with aldehydes. This study investigated the oxidation kinetics of different aldehydes by chlorous acid. Reaction rates with chlorous acid at 25 °C were obtained for formaldehyde (11.0 M−1 s−1), vanillin (0.59 M−1 s−1), veratraldehyde (1.00 M−1 s−1), benzaldehyde (5.6 M−1 s−1), glucose (3.39 × 10−3 M−1 s−1), glycolaldehyde (39.0 M−1 s−1), and 5-formyl-2-furancarboxylic acid (5.2 M−1 s−1). The activation energies varied between 26 and 63 kJ/mol. The rate-determining step was shown to be the addition of chlorous acid to the aldehyde structure. The practical significance of the Cl(III) reaction with aldehyde structures in chlorine dioxide bleaching was discussed. It was concluded that various aldehydes present in cellulosic pulp are at least partly responsible for the consumption of Cl(III) in chlorine dioxide bleaching. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9018885 [article] Kinetics of aldehyde oxidation by chlorous acid [texte imprimé] / Tuula Lehtimaa, Auteur ; Susanna Kuitunen, Auteur ; Ville Tarvo, Auteur . - 2010 . - pp. 2688–2693. industrial Chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 6 (Mars 2010) . - pp. 2688–2693 Mots-clés : Kinetics  Aldehyde  Oxidation  Chlorous  Acid Résumé : Chlorous acid is known to react with aldehydes. This study investigated the oxidation kinetics of different aldehydes by chlorous acid. Reaction rates with chlorous acid at 25 °C were obtained for formaldehyde (11.0 M−1 s−1), vanillin (0.59 M−1 s−1), veratraldehyde (1.00 M−1 s−1), benzaldehyde (5.6 M−1 s−1), glucose (3.39 × 10−3 M−1 s−1), glycolaldehyde (39.0 M−1 s−1), and 5-formyl-2-furancarboxylic acid (5.2 M−1 s−1). The activation energies varied between 26 and 63 kJ/mol. The rate-determining step was shown to be the addition of chlorous acid to the aldehyde structure. The practical significance of the Cl(III) reaction with aldehyde structures in chlorine dioxide bleaching was discussed. It was concluded that various aldehydes present in cellulosic pulp are at least partly responsible for the consumption of Cl(III) in chlorine dioxide bleaching. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9018885

Reactions and kinetics of Cl(III) decomposition / Tuula Lehtimaa in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5284–5290 Titre : Reactions and kinetics of Cl(III) decomposition Type de document : texte imprimé Auteurs : Tuula Lehtimaa, Auteur ; Ville Tarvo, Auteur ; Gérard Mortha, Auteur Année de publication : 2008 Article en page(s) : p. 5284–5290 Note générale : Bibliogr. p. 5289-5290 Langues : Anglais (eng) Mots-clés : Chlorite  acid;  Chlorous  acid;  Self-decomposition Résumé : Several pathways leading to the decomposition of chlorite and chlorous acid have been published. In this study, both experimental and computational approaches have been applied to clarify the authenticity of the different routes. The decomposition of chlorine (III), i.e. chlorous acid and chlorite, was monitored with iodometric titration at changing chloride concentrations, temperature, and existence of iron (III) at pH 1−3. Dimethylsulfoxide (DMSO) was used to prevent hypochlorous acid from reacting with chlorite. Chlorine dioxide was not formed in the absence of metals when hypochlorous acid and chlorine were trapped. The self-decomposition of Cl(III) proceeds only via the acidic form while chlorite is stable. Chloride ions enhanced the chlorous acid decomposition rate especially at low pH. Chlorite decomposes in the presence of Fe3+ ions. General kinetic parameters and their temperature dependencies were determined for chlorous acid self-decomposition. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0714089 [article] Reactions and kinetics of Cl(III) decomposition [texte imprimé] / Tuula Lehtimaa, Auteur ; Ville Tarvo, Auteur ; Gérard Mortha, Auteur . - 2008 . - p. 5284–5290. Bibliogr. p. 5289-5290 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5284–5290 Mots-clés : Chlorite  acid;  Chlorous  acid;  Self-decomposition Résumé : Several pathways leading to the decomposition of chlorite and chlorous acid have been published. In this study, both experimental and computational approaches have been applied to clarify the authenticity of the different routes. The decomposition of chlorine (III), i.e. chlorous acid and chlorite, was monitored with iodometric titration at changing chloride concentrations, temperature, and existence of iron (III) at pH 1−3. Dimethylsulfoxide (DMSO) was used to prevent hypochlorous acid from reacting with chlorite. Chlorine dioxide was not formed in the absence of metals when hypochlorous acid and chlorine were trapped. The self-decomposition of Cl(III) proceeds only via the acidic form while chlorite is stable. Chloride ions enhanced the chlorous acid decomposition rate especially at low pH. Chlorite decomposes in the presence of Fe3+ ions. General kinetic parameters and their temperature dependencies were determined for chlorous acid self-decomposition. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0714089

The kinetics and stoichiometry of the reaction between hypochlorous acid and chlorous acid in mildly acidic solutions / Ville Tarvo in Industrial & engineering chemistry research, Vol. 48 N° 13 (Juillet 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. Titre : The kinetics and stoichiometry of the reaction between hypochlorous acid and chlorous acid in mildly acidic solutions Type de document : texte imprimé Auteurs : Ville Tarvo, Auteur ; Tuula Lehtimaa, Auteur ; Susanna Kuitunen, Auteur Année de publication : 2009 Article en page(s) : pp. Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Hypochlorous  acid  Chlorous  acid  Stoichiometry  Kinetics Résumé : The kinetics and stoichiometry of the reaction between hypochlorous acid and chlorous acid was studied under mildly acidic conditions (pH = 2.5−4.7). The experiments were conducted in dilute solutions (10−4−10−3 M) at T = 5−25 °C. External buffer compounds were not used. Chlorous acid, chlorine dioxide, and chlorate concentrations were monitored with titrimetric methods. Rate coefficients and activation energies were determined for the five main steps of the kinetic model (others were adopted from literature). Both hypochlorous acid and chlorine were found to react at an appreciable rate with chlorous acid/chlorite. Chloride ion was found to promote both the overall reaction rate and chlorine dioxide/chlorate ratio. The results may be exploited in optimizing the red-ox efficiency of technical chlorine dioxide bleaching processes. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801798m [article] The kinetics and stoichiometry of the reaction between hypochlorous acid and chlorous acid in mildly acidic solutions [texte imprimé] / Ville Tarvo, Auteur ; Tuula Lehtimaa, Auteur ; Susanna Kuitunen, Auteur . - 2009 . - pp. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. Mots-clés : Hypochlorous  acid  Chlorous  acid  Stoichiometry  Kinetics Résumé : The kinetics and stoichiometry of the reaction between hypochlorous acid and chlorous acid was studied under mildly acidic conditions (pH = 2.5−4.7). The experiments were conducted in dilute solutions (10−4−10−3 M) at T = 5−25 °C. External buffer compounds were not used. Chlorous acid, chlorine dioxide, and chlorate concentrations were monitored with titrimetric methods. Rate coefficients and activation energies were determined for the five main steps of the kinetic model (others were adopted from literature). Both hypochlorous acid and chlorine were found to react at an appreciable rate with chlorous acid/chlorite. Chloride ion was found to promote both the overall reaction rate and chlorine dioxide/chlorate ratio. The results may be exploited in optimizing the red-ox efficiency of technical chlorine dioxide bleaching processes. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801798m