Synergistic wood preservatives involving EDTA, irganox 1076 and 2-hydroxypyridine-N-oxide

The efficiency of 2-hydroxypyridine-N-oxide (2-HPNO) against wood degradation by the white-rot fungus Coriolus versicolor was demonstrated by monitoring weight loss of treated and untreated wood blocks. The fungistatic properties of 2-HPNO are related to the presence of the hydroxamic acid function as shown using several analogs. Using response surface methodology, strongly significant synergy was observed between either the chelator ethylenediaminetetraacetic acid (EDTA) and 2-HPNO or the hindered phenolic antioxidant Irganox 1076 and 2-HPNO. 2-HPNO is subjected to oxidation by peroxidase explaining the synergy observed with the antioxidant. The chelating properties of 2-HPNO may also explain the synergy observed with EDTA. The implications of the observed synergy for the design of new wood preservation strategies are also discussed.