Dehalogenates 4-chlorobenzoyl-CoA, 4-iodobenzoyl-CoA, 4-bromobenzoyl-CoA and, at a slower rate, 4-fluorobenzoyl-CoA. Does not dehalogenate 2-chlorobenzoyl-CoA or 3-chlorobenzoyl-CoA. 4-chlorobenzoyl-CoA + H2O = 4-hydroxybenzoyl-CoA + chloride + H(+) Optimum pH is 8.0 in MOPS buffer at 30 degrees Celsius, 7.5 in 0.1 M potassium phosphate buffer at 30 degrees Celsius, and 7.4 in 20 mM potassium phosphate/2 mM DTT buffer at 30 degrees Celsius. Retains full activity in MOPS buffer between pH 6.5 and 10.0. Is irreversibly damaged below pH 6.5 in MOPS buffer, enzyme treated at pH 6.0 in MOPS buffer only regains 40% of its original activity after re-equilibration at pH 7.2. When treated at pH 5.2 or 10.1 in 20 mM potassium phosphate/2 mM DTT buffer activity is lost completely, but is recovered within 17 minutes following readjustment to pH 7.4. Optimum temperature is 45 degrees Celsius. Activity is lost after 5 minutes incubation at 60 degrees Celsius, but one-fifth of this activity is restored after cooling to 45 degrees Celsius. Xenobiotic degradation; 4-chlorobenzoate degradation; 4-hydroxybenzoate from 4-chlorobenzoate: step 2/3. Homotetramer. Belongs to the enoyl-CoA hydratase/isomerase family.