Method for the preparation of α,α,α′,α′-tetrafluoro-p-xylene

A method of preparing α,α,α′,α′-tetrafluoro-p-xylene comprising the steps of:

• reaction of an α,α,α′,α′-tetrachloro-p-xylene with alkaline metal fluoride and a phase transfer catalyst in xylene to obtain α,α,α′,α′-tetrafluoro-p-xylene, wherein fluoride reagent for α,α,α′,α′-tetrafluoro-p-xylene is MF and M is selected from a group consisting of Li, Na, K and Cs, and the amount ranges from 1 to 100 times of α,α,α′,α′-tetrachloro-p-xylene mole number, and solvent for α,α,α′,α′-tetrafluoro-p-xylene is selected from a group consisting of o-xylene, m-xylene, p-xylene, and xylene, and the amount ranges from 0.01 to 10 kg/mole with respect to mole number of α,α,α′,α′-tetrafluoro-p-xylene, and the phase transfer catalyst is Ph4PX and X is selected from a group consisting of Cl, Br and I, and the amount ranges from 0.1 to 1000 g/mole with respect to mole number of α,α,α′,α′-tetrafluoro-p-xylene, and reaction temperature is from 25 to 400° C.