METHOD FOR REDUCING THE CONCENTRATION OF SO 3 IN A REACTION MIXTURE COMPRISING METHANE SULFONIC ACID AND SO 3

The present invention refers to a method for reducing SO3 concentration in a mixture comprising methane sulfonic acid and SO3, the method comprising:i. providing a mixture comprising methane sulfonic acid and SO3,ii. determining the amount of an additive necessary to reduce the concentration of SO3 in the mixture by forming a reaction product between the additive and SO3,iii. introducing said predetermined amount of the additive into the mixture;iv. optionally repeating steps ii. and iii.,wherein the determination of the amount of additive necessary to reduce the concentration of SO3 in the mixture is performed by measuring conductivity and/or density of the reaction mixture.