Based on what I have red I would expect reaction between SOCl2 and H2SO4 with formation of ClSO3H / S2O5Cl2 / SO3 mixture, probably without heating.
And I think you already have proved that, woelen, if I remember it properly you have some demo of K2Cr2O7 + H2SO4 + SOCl2 on your website with forming
chromyl chloride which is usually formed when ClSO3H reacts with CrO3. |