Synthesis Of CF₂O Fluorobenzene Compounds And Their Key Intermediates

TFT liquid crystal material is one of the key optoelectronic materials of TFT-LCD,and its performance determines the quality of TFT-LCD devices.In the liquid crystal materials found at present,the liquid crystal materials and hydrocarbon liquid crystal materials are mainly used.The two kinds of liquid crystal materials have high stability and low viscosity.At the same time,the fluoride system has high polarity.The different requirements of TFT-LCD panel for liquid crystal materials can be realized through mixing multiple mono LC materials.The CF₂O Fluorobenzene compounds LC materials with high dielectric anisotropy and the rotation of the extremely low viscosity,fast response and low voltage driver is suitable for the panel,can reduce the power consumption of the display device,improve the clearing point of LC mixture,and improve the working temperature range.My subject study developed CF₂O Fluorobenzene compounds and their key intermediates.Using 2,3,4-Trifluoroaniline as raw material,1-bromo-3,4,5-trifluorobenzene is obtained by bromination and reduction.Then the key intermediate 3,4,5-Trifluorophenol is obtained through ammoniation,diazotization and hydrolysis,and a new process of"one pot"method is developed to introduce two fluorine in liquid crystal molecules.A new process of introducing CF2O into liquid crystal molecules was developed,1)Toluene and Isooctyl alcohol were used as solvents,mixed organic acid,Dimercaptopropane and Trifluoromethanesulfonic acid,and Dehydrate in a reflux condition,forming a kind of trifluoromethyl sulfonate,which does not need to be purified and directly used for the next reaction.2)add 3,4,5-Trifluorophenol,Triethylamine trifluoride at low temperature of-70,and get the target compound under bromination reaction.