Production information for Chloroxynil is absent in the general literature. However, as a chlorinated analogue of bromoxynil, chloroxynil would have been manufactured by selective chlorination of a hydroxy substituted benzonitrile precursor, typically 4 hydroxybenzonitrile, followed by controlled introduction of chlorine atoms at the 3 and 5 positions of the aromatic ring. The resulting 3,5 dichloro 4 hydroxybenzonitrile would then be purified by crystallisation to yield technical grade chloroxynil.
