In our continuing efforts to design nontoxic and biodegradable fuel system icing inhibitor (FSII) compounds with improved fuel solubility and antiicing ability, and nontoxic deicers for aircraft and runways, we report semiempirical molecular orbital calculations of hexadecane-walker partition coefficients (log Ph-w). The evaluation of hexadecane-water partition coefficients for;a series of isomers by an empirical method yields only a single number, whereas our application of solvent models within a molecular orbital approach to methyl- and acetyl-substituted D-glucopyranose results in a range of log Ph-w values. Furthermore, these values are lowered when the conformational response of the FSII to the solvent is included. The extent of this effect depends on the solvation model used and is more pronounced for acetyl-substituted glucopyranoses than for methyl-substituted derivatives. Four methyl substituents in any substitution pattern are required for preferential partitioning into fuel whereas only specific tetraacetylglucopyranose isomers-1,2,3,4-alpha-D-tetraacetylglucopyranose, 1,2,3,6-alpha-D-tetraacetylglucopyranose, 1,2,4,6-alpha-D-tetraacetylglucopyranose, 1,2,4,6-beta-D-tetraacetylglucopyranose, 1,3,4,6-alpha-D-tetraacetylglucopyranose, and 1,3,4,6-beta-D-tetraacetylglucopyranose-will do so.