Chemical exchange between gaseous boron trifluoride (BF3) and the liquid BF3.dimethyl ether complex has been used extensively for the commercial fractionation of boron isotopes. Several compounds never before studied as donors in the isotope exchange reaction were examined to determine if they were viable replacements for the dimethyl ether system. For the first time, ketones were studied as donors in the boron isotope exchange reaction. The ketones examined were acetone, methyl isobutyl ketone, and diisobutyl ketone. The ideal single stage separation factors, alpha, measured for these ketones were between 1.038 and 1.043 at 30-degrees-C. The observed separation factor for a fourth donor system, nitromethane, was 1.067 at 30-degrees-C, well above that predicted by theory or observed for any known BF3/donor system. For each of the systems studied, the separation factors were greater than the value of alpha = 1.027 reported for the dimethyl ether/BF3 system at 30-degrees-C. In view of the experimentally observed separation factors, these donor systems are potential replacements for dimethyl ether in large-scale boron isotope fractionation schemes. It is concluded that plant size could be significantly reduced by using any of these donors rather than dimethyl ether.