IMPROVED DONORS FOR THE SEPARATION OF THE BORON ISOTOPES BY GAS-LIQUID EXCHANGE-REACTIONS

Chemical exchange between gaseous boron trifluoride (BF3) and the liqu id BF3.dimethyl ether complex has been used extensively for the commer cial fractionation of boron isotopes. Several compounds never before s tudied as donors in the isotope exchange reaction were examined to det ermine if they were viable replacements for the dimethyl ether system. For the first time, ketones were studied as donors in the boron isoto pe exchange reaction. The ketones examined were acetone, methyl isobut yl ketone, and diisobutyl ketone. The ideal single stage separation fa ctors, alpha, measured for these ketones were between 1.038 and 1.043 at 30-degrees-C. The observed separation factor for a fourth donor sys tem, nitromethane, was 1.067 at 30-degrees-C, well above that predicte d by theory or observed for any known BF3/donor system. For each of th e systems studied, the separation factors were greater than the value of alpha = 1.027 reported for the dimethyl ether/BF3 system at 30-degr ees-C. In view of the experimentally observed separation factors, thes e 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 rath er than dimethyl ether.