Process for operating a plant for preparing an alkanesulfonic acid

Abstract

The present invention relates to a process for operating a plant for preparing an alkanesulfonic acid, wherein said alkanesulfonic acid is prepared by oxidation of an alkylmercaptan, dialkydisulfide and/or dialkylpolysulfide and the one or more alkyl radicals of the alkylmercaptan, dialkydisulfide and/or dialkylpolysulfide are identical with the alkyl radical of the alkylsulfonic acid to be prepared, characterized in that the oxidation is performed in the presence of an at least stoichiometric amount of an oxoacid of nitrogen, e.g. nitric acid, relative to the amount of said alkylmercaptan, dialkyldisulfide and/or dialkylpolysulfide during the start-up phase of the plant of the plant, wherein the start up phase comprises the steps adding an oxoacid of nitrogen to the reactor, adding sulfur-containing reactant progressively so that it is converted to alkanesulfonic acid, filling up the compile volume of the reactor by adding progressively sulfur-containing reactant and if needed oxoacid of nitrogen to make sure that it is in excess, once the reactor is full, transitioning out of the start-up phase by adding an oxygen containing fluid, and during the running phase, keeping the reaction volume full by balancing the volume of product withdrawn with the volume of sulfur-containing reactant added.