Parylene D Factory will tell you about the preparation of Parylene D monomer.
1. Phenylene ring chlorination of p-xylene ring dimer
1) using p-xylene ring dimer as raw material, using N-chlorosuccinimide as chlorinating agent (NCS), benzoyl peroxide (BPO) as initiator, chlorinating to obtain product Tetrachloro-p-xylene ring dimer;
2) using a p-xylene ring dimer as raw material, mixing a carbon tetrachloride solution containing chlorine gas with iron powder and p-xylene ring dimer, and chlorinating it with chlorine gas to obtain a product tetrachloro-p-xylene Ring two bodies;
3) Using dichloro-p-xylene ring dimer as raw material, using NCS as chlorinating agent and BPO as initiator, the raw material is chlorinated to obtain the product tetrachloro-p-xylene ring dimer.
2. Using p-methyltrimethylammonium chloride as raw material
The solvent after reacting methyltrimethylbenzyl chloride with trimethylamine, under the action of NCS and BPO, chlorination to form dichloro quaternary ammonium salt; the second step, according to Hofmann elimination method, in alkaline environment, season Mr. ammonium salt is a quaternary amine base, and the latter two quaternary amine bases are re-cyclically synthesized into tetrachloro-p-xylene ring dimers.
3. Using 2,5-dichloro-p-xylene as raw material
Using 2,5-dichloro-p-xylene as raw material, halogenated by NCS, NBS, HBr/H2O2 system to form a halogenated product, and react with trimethylamine to form a quaternary ammonium salt. Finally, the trimethylamine and water were removed by Hofmann elimination.