Rs. Herbst et Fp. Mccandless, IMPROVED DONORS FOR THE SEPARATION OF THE BORON ISOTOPES BY GAS-LIQUID EXCHANGE-REACTIONS, Separation science and technology, 29(10), 1994, pp. 1293-1310
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.