INVESTIGATIONS OF AMMONIACAL COPPER(II) OCTANOATE IN AQUEOUS-SOLUTIONS AND ITS DETERMINATION IN IMPREGNATED WOOD

Copper(II) octanoate in aqueous ammonia solutions belongs to the group of relatively new environment friendly waterborne preservatives, ammo niacal copper carboxylates. Electron paramagnetic resonance, EPR, was used to study the behaviour of Cu(II) octanoate in aqueous ammonia sol ution and in spruce sapwood, impregnated with this solution. From the comparison of EPR spectra of CuSO4 and Cu(II) octanoate aqueous ammoni a solutions it was established that in the Cu(II) octanoate-water-ammo nia system, Cu(II) remains in Cu(II) octanoate-ammonia complex. That m eans that the active substance in treatment of wood with this solution is copper(II) octanoate-ammonia complex and not tetraamminecopper(II) . The samples of spruce sapwood were impregnated with 1 X 10(-2) mol/l copper(II) octanoate-water-ammonia solution and EPR spectra of the dr ied samples were recorded. It was stated that in wood Cu(II) from Cu(I I) octanoate-water-ammonia solution is complexated. After soaking the samples for 24 hours in the Cu(II) octanoate aqueous ammonia solution, the radial penetration depth of 1.2 mm for Cu(II) was determined. Pre liminary experiments on leaching of the investigated substance showed that after first 24 hours of the experiment, copper concentration in t he impregnated samples decreased for approximately 35% and that subseq uent leaching did not further change the Cu(TI) concentration, within the detection limit.