To provide an industrially applicable impurities-removing method, alternative to distillation, capable of producing monofluoromethane substantially containing neither trifluoromethane nor unsaturated compounds, in view of the fact that: monofluoromethane produced or treated in a vapor phase may be accompanied by trifluoromethane due to equilibrium, fluorination reaction or disproportional reaction; wherein, as their boiling points are close to each other, they cannot be efficiently separated from each other by distillation.
A method for producing monofluoromethane is provided, including a step of bringing a trifluoromethane-containing monofluoromethane composition into contact with a trifluoromethane treatment liquid containing an amide of formula (1) (wherein, R1, R2 and R3 are each H or alkyl, being optionally bound together to form a ring, wherein the carbon atom on the ring is optionally substituted by an oxygen, nitrogen and/or sulfur atom) and a base; and a step of bringing the composition into contact with sulfuric acid.
TAKADA NAOKADO
IMURA HIDEAKI
