反应详情

WO 00/31027 discloses a process for oxidizing dimethyl disulfide with nitric acid to MSA, the oxides of nitrogen which are formed being reacted with O2 to give nitric acid again and this being recycled to the process. CN1 810 780 A discloses a process in which ammonium sulfite and/or ammonium hydrogen sulfite is reacted with dimethyl sulfate to give ammonium methanesulfonate and ammonium sulfate. The ammonium sulfate can be precipitated with Ca2+ as CaSO4. MSA can be liberated from the remaining Ca(CH3SO3)2 with sulfuric acid and can be worked up, once again CaSO4 being precipitated. EP 906 904 A2 discloses a process in which sodium sulfite is reacted with dimethyl sulfate. MSA can be liberated from the resulting mixture after acidification with concentrated sulfuric acid. The three last mentioned processes have the advantage that the MSA obtained is virtually free of chlorine compounds.