Brightness reversion of mechanical pulps. VIII. Fate of dienic additives during brightness reversion of high-yield pulp

• Published in: Journal of wood chemistry and technology Vol. 17; no. 1/2; pp. 27 - 39
• Main Authors: Harvey, L.C. (Agnes Scott College, Atlanta, GA.), Cook, C, Ragauskas, A.J
• Format: Journal Article
• Language: English
• Published: Colchester Taylor & Francis Group 01.02.1997; Taylor & Francis
• Subjects: Applied sciences; CHEMICOPHYSICAL PROPERTIES; ELABORACION DE PULPA; ESTABILIDAD; Exact sciences and technology; MECHANICAL METHODS; METHODE MECANIQUE; METODOS MECANICOS; Paper, paperboard, non wovens; PASTA; PATE CELLULOSIQUE; Polymer industry, paints, wood; Properties and testing; PROPIEDADES FISICOQUIMICAS; PROPRIETE PHYSICOCHIMIQUE; PULP; PULPING; REDUCTION EN PATE; STABILITE; STABILITY; Wood. Paper. Non wovens; Lignin; Reversion; Model compound; Optical properties; Paper pulp; High yield pulp; Whiteness; Photochemical degradation; Chemithermomechanical pulp
• ISSN: 0277-3813; 1532-2319
• DOI: 10.1080/02773819708003116

The photostabilization mechanism of 1,4-dihydro-2-methylbenzoic acid was examined with a lignin model compound in solution and on BCTMP pulp. Photodegradation of 3,4-dimethoxy-alpha-(2'-methoxyphenoxy)-acetophenone (1), dissolved in benzene, was shown not to be influenced by the addition of the diene additive, suggesting that the additive does not influence the initial photochemistry of lignin model compound 1. Product analysis indicated that the addition of the diene additive enhanced formation of 3,4-dimethoxyacetophenone, one of the principal products formed from photofragmentation of compound 1. These results were attributed to hydrogen donation from the diene to the phenacyl radical. Photolysis of 1,4-dihydro-2-methylbenzoic acid impregnated on BCTMP test sheets revealed a gradual conversion of the diene additive into o-toluic acid; this reaction was attributed to a hydrogen donation mechanism