Method for improving preservation stability of 2,2-difluoroacetaldehyde

A method for improving preservation stability of 2,2-difluoroacetaldehyde, comprising:

• a first step of forming a 2,2-difluoroacetaldehyde-alcohol composite system that contains a hemiacetal of the 2,2-difluoroacetaldehyde as represented by the formula (3) and a free alcohol as represented by the formula (2)
• where R2 represents a C1-C6 linear, branched or cyclic hydrocarbon group in which a part or all of hydrogen atoms may be substituted with a fluorine atom
• R2—OH (2)
• where R2 has the same definition as in the formula (3);
• and
• a second step of storing the 2,2-difluoroacetaldehyde-alcohol composite system in a storage container,
• wherein, at the initiation of storage of the 2,2-difluoroacetaldehyde-alcohol composite system in the storage container, the 2,2-difluoroacetaldehyde-alcohol composite system has a substantially neutral pH and a water content of 1000 ppm or lower;
• and
• wherein, at the initiation of storage of the 2,2-difluoroacetaldehyde-alcohol composite system in the storage container, the total molar amount of the alcohol in the 2,2-difluoroacetaldehyde-alcohol composite system is 1.15 to 4.00 times the total molar amount of the 2,2-difluoroacetaldehyde.