A process for manufacturing of an alkanesulfonic acid, and an alkanesulfonic acid manufactured by the process. Aspects of the process may involve manufacturing an alkanesulfonic acid by reaction of an initiator composition with an alkane and sulfur trioxide by preparing an initiator composition by reacting aqueous hydrogen peroxide with alkanesulfonic acid and/or H2SO4; and reacting the initiator composition with sulfur trioxide and alkane to form an alkanesulfonic acid, wherein an alkane with a purity of at least 98.0 mol-% is used.