Equilibrium constants between boron trifluoride etherate and carbonyl compounds in chloroform solution

Equilibrium constants for boron trifluoride complexation with carbonyl comp ounds relative to diethyl ether were determined in CDCl3, With benzaldehyde the equilibrium constant is 0.208. There is a 1.28-fold preference for BF3 bonding to benzaldehyde-D over benzaldehyde-H. The rho(+) value for comple xation with substituted benzaldehydes is -2,0. Equilibrium constants with c yclohexanone and isobutyraldehyde were found to be not very different from those predicted from the heats of addition of BF3 relative to that for diet hyl ether. The heats of addition can be correlated with Taft's beta values and with beta' values.