Synthetic method of difluoroacetic acid

The invention relates to the technical field of difluoroacetic acid, in particular to a synthesis method of difluoroacetic acid, which comprises the following steps: mixing purified HCFC-122 and calcium hydroxide, stirring to react, and freezing and condensing to absorb 1, 1-difluoro-1, 1-dichloroethylene generated by the reaction; the method comprises the following steps: feeding a potassium hydroxide methanol solution into a preheater by using a pump, and simultaneously feeding 1, 1-difluoro-1, 1-dichloroethylene into a reactor by using a pump to obtain 2, 2-difluoro-1, 1-dichloroethyl methyl ether; the preparation method comprises the following steps: adding 2, 2-difluoro-1, 1-dichloroethyl methyl ether into a reaction kettle, and dropwise adding concentrated sulfuric acid to obtain a sulfate compound; the method comprises the following steps: adding water into a reaction kettle, dropwise adding a sulfate compound into the reaction kettle, controlling the reaction temperature by using cooling water, heatin