Disclosed is a biocide concentrate composition to be incorporated into oil-based formulations useful for the treatment and preservation of wood. Also disclosed are oil-based biocide compositions and creosote based biocide compositions.

Provided is a wood treatment composition comprising a reaction product produced by reacting a mixture, which includes creosote and a fatty ester component, in the presence of a Lewis acid catalyst. The reaction mixture may optionally include bunker oil and/or a borate ester. The mixture may comprise i) at least about 85 wt % creosote; and ii) at least about 1 wt % of an ester component containing one or more C.sub.8-C.sub.50 fatty esters. Also provided are wood treated with the composition and methods for using the composition to treat wood.

Provided is a wood treatment composition comprising a reaction product produced by reacting a mixture, which includes creosote and a fatty ester component, in the presence of a Lewis acid catalyst. The reaction mixture may optionally include bunker oil and/or a borate ester. The mixture may comprise i) at least about 85 wt % creosote; and ii) at least about 1 wt % of an ester component containing one or more C.sub.8-C.sub.50 fatty esters. Also provided are wood treated with the composition and methods for using the composition to treat wood.