Patent ID: 7060862

Claim:
A method for synthesizing α,α,α′,α′-tetrachloro-p-xylene with a high purity, which comprises: performing a first stage reaction by reacting terephthaldicarboxaldehyde with a mixture of SOCl 2 and dimethylformamide to obtain a product mixture including α,α,α′,α′-tetrachloro-p-xylene as a major portion and 4-dichloromethyl benzaldehyde by-product; performing a second stage reaction by adding SOCl 2 and DMF into said product mixture; and contacting the resulting product mixture from the second stage reaction with a cooling water to obtain a solid product of α,α,α′,α′-tetrachloro-p-xylene with a purity of 90–99 mole %, wherein an amount of SOCl 2 used in the first stage reaction is 1.5–3 times of that of terephthaldicarboxaldehyde used in the first stage reaction in mole, and an amount of SOCl 2 used in the second stage reaction is 1.5–3 times of that of terephthaldicarboxaldehyde used in the first stage reaction in mole.