Abstract

A novel type of chemical modification of wood was developed and applied to functionalise wood permanently with organoboron compounds. The covalent attachment of metalloid substituents via a benzotriazolyl-activated benzoic acid to wood hydroxy groups was in focus. Thus, standard modification procedures in wood chemistry – such as the acetylation – are improved by avoiding either the loss of half the reagent in the case of acid anhydrides or the release of corrosive hydrochloric acid in the case of carboxylic acid chlorides. The introduced boron moiety could be a contribution to solve a long-lasting problem in the field of wood protection: chemical fixation of an organoboron compound by means of a well-defined covalent bond. Accordingly, the hitherto insufficient long-term availability of conventionally spread boron compounds as wood protecting agents caused by leaching can now be avoided. The investigation was also extended to arylsilyl compounds, as a second type of organometal substances, which potentially allow for subsequent chemical modifications by ipso-substitution. The presented wood modification reactions yielded weight percent gain values from 14% to 31% on beech wood, spruce wood, and pine sapwood meal (approximately 500 μm in diameter) or pine sapwood veneer chips. The modified meals and chips were analysed by IR spectroscopy.