Reactions between peracetic acid and lipophilic extractives – methodologies and implications in post bleaching of kraft pulps

A1 Originalartikel i en vetenskaplig tidskrift (referentgranskad)


Interna författare/redaktörer


Publikationens författare: Jan-Erik Raitanen, Anna Sundberg, Jonas Konn, Annika Smeds, Stefan Willför
Förläggare: De Gruyter GmbH & Co
Publiceringsår: 2016
Tidskrift: Holzforschung
Tidskriftsakronym: HOLZFORSCHUNG
Volym: 70
Nummer: 8
Artikelns första sida, sidnummer: 747
Artikelns sista sida, sidnummer: 754
eISSN: 1437-434X


Abstrakt

Pulp mills constantly look for opportunities to increase their production capacity without major investments, as well as to save in overall bleaching costs. Peracetic acid (PAA) is used in post bleaching of kraft pulps to increase pulp brightness, to prevent brightness reversion in pulp storage, and to prohibit problems caused by extractives. However, the rates and significance of reactions between PAA and lipophilic extractives in pulp bleaching are not known in detail. Hence, the reactions between PAA and model compounds of extractives have been studied as emulsions in water and directly in methyl-tert-butyl ether (MTBE). Unsaturated compounds were found to be reactive in both water and MTBE, and the conventional extractive analyses had to be modified. Freeze-drying the reaction mixture with subsequent trimethylsilylation and GC-analysis was a very effective analytical approach. As a result of PAA treatment, fatty acids and sterols with double bonds were shown to form epoxides and the corresponding diols. Dehydroabietic acid (DeAb) also reacted with PAA by oxidation of the benzylic position. After longer reaction times, the reaction products of the extractives were further degraded or formed cross-linked aggregates. The epoxides and diols were also identified in samples from pulp mills applying PAA in post bleaching.


Nyckelord

extractives, kraft pulp, model compounds, oxidation of extractives, peracetic acid, pitch problems, post bleaching

Senast uppdaterad 2019-06-12 vid 04:43