Behaviour of acid halides in disulphuric acid

From cryoscopic, conductometric, and spectral studies of the solutions of various acid halides in disulphuric acid, it has been found that nitryl chloride and fluoride, nitrosyl chloride, acetyl chloride and bromide, isobutyryl chloride, benzoyl chloride and mesitoyl chloride have ionizable halide ions where as phosphoryl chloride and bromide, thiophosphoryl chloride and bromide, selenoyl chloride and monochloroacetyl chloride have a predominantly basic oxygen atom, while thionyl chloride and bromide, sulphuryl chloride and carbonyl chloride have neither sufficiently basic oxygen atom nor ionizable halide ion. Oxalyl chloride decomposes to form carbon monoxide and carbonyl chloride where as succinyl chloride is simply monoprotonated in disulphuric acid. Investigations of the solutions of acid halides in disulphuric acid provide a simple method to determine their ionic nature.