Method for producing α,α-difluoroacetaldehyde

A method for producing an α,α-difluoroacetaldehyde of the formula [3] or α,α-difluoroacetaldehyde alkyl hemiacetal of the general formula [4], comprising reaction of an α,α-difluoroacetate of the general formula [1] with hydrogen in the presence of a ruthenium complex of the formula [2] and a base,

• in which R1 represents an alkyl group or substituted alkyl group,
• in which Ph represents a phenyl group,
• in which R2 has the same meaning as R1 in the general formula [1],
• wherein the reaction is performed under conditions that:
• the base is an alkali metal alkoxide and is used in an amount of 0.001 mol or more per 1 mol of the α,α-difluoroacetate;
• and
• a pressure the hydrogen used is 1.0 MPa to 10 MPa in terms of absolute pressure,
• whereby a rate of conversion of the α,α-difluoroacetate during the reaction is 80% or higher;
• and a selectivity of the α,α-difluoroacetaldehyde or α,α-difluoroacetaldehyde alkyl hemiacetal formed from the α,α-difluoroacetate to β,β-difluoroethanol formed as a by-product during the reaction is in a range of α,α-difluoroacetaldehyde or α,α-difluoroacetaldehyde alkyl hemiacetal:β,β-difluoroethanol=90% or higher:10% or lower.