Conversion methods of methyl bisulfate dissolved in oleum into methan

Three methods of converting methyl bisulfate dissolved in oleum into methanol have been described. In the first one, the ester present in the oleum was hydrolyzed to methanol by adding water to the mixture. In the second method the ester was vaporized in the flowing air stream and then, methyl bisulfate vapour was absorbed in water. In the third one, the ester was separated from the post-reaction mixture by means of membrane distillation, sucked by a pump and absorbed in water. It was found that the two-stage membrane distillation was the most effective method.