Tetraethylene glycol thermooxidation and the influence of certain compounds relevant to conserved archaeological wood

The degradation of tetraethylene glycol (TEG) was studied at 70 °C under dry air and nitrogen. Degradation products were detected using gas chromatography-mass spectrometry (GC–MS). They were mono-, di- and tri-ethylene glycol, mono- and di-formates of mono-, di-, tri- and tetra-ethylene glycol and formic acid. The rate of TEG degradation was significantly decreased by approximately 10 mmol/l KI, FeCl3, Cu(CH3COO)2, MnO2 and CuSO4, small amounts of fresh oak wood sawdust and gypsum-containing scrapings from the wood surface of the Vasa ship in Stockholm. Thus certain salts and natural components of archaeological wood are able to inhibit oxidative degradation of TEG. NaFe3(SO4)2(OH)6 (Natrojarosite), FeS2 (pyrite), FeSO4, Fe2(SO4)3, NiCl2, NiSO4, Fe, Cu, Fe2O3, CuO, NaHSO4 and natrojarosite-containing scrapings from the Vasa had no major effect on the rate of oxidation.