Study On Synthesis Of 5-o-tolyl-2-pentene

5-o-tolyl-2-pentene (OTP) is an intermediate for preparing 2,6-dimethylnaphtha- lene (2,6-DMN) from o-xylene and 1,3-butadiene. 2,6-DMN is used as a precursor of 2,6-naphthalenedicarboxylic acid (2,6-NDCA) which is an important raw material used to synthesize high performance polyethylene naphthalate (PEN) and liquid crystalline polymers (LCP). With the development of PEN application field, the need of 2,6-DMN will be increasing. Currently, 2,6-DMN is almost dependent on import in China. Therefore there is a need to do more research work about 2,6-DMN production technology especially about reducing the production cost and enlarging production scale.The purpose of this thesis is to study alkenylation reaction of o-xylene with 1,3-butadiene using two catalysts. Firstly, OTP was prepared by o-xylene and 1,3-butadiene under sodium as catalyst and potassium carbonate as dispersing agent. The effect of catalyst dosage, mass ratio of dispersing agent to catalyst, reaction temperature, reaction time and molar ratio of o-xylene to 1,3-butadiene were investigated. The results indicated that the yield of OTP was 71.2% under the optimal experimental condition, which means that the molar ratio of o-xylene to 1,3-butadiene was 5∶1, reaction temperature was 175℃, reaction time was 2.5 hours, catalyst dosage was 0.25%, mass ratio of dispersing agent to catalyst was 16∶1. Secondly, OTP was prepared by o-xylene and 1,3-butadiene with Na-K catalyst activated by ultrasonic. It was found experimentally that the optimal ultrasonic parameters were that ultrasonic frequency was 40 kHz, ultrasonic power was 80W and ultrasonic action time was 3 hours. Under these optimal ultrasonic conditions, the best technical parameters were confirmed that the molar ratio of o-xylene to 1,3-butadiene was 5∶1, reaction temperature was 175℃, reaction time was 5.5 hours, catalyst dosage was 0.25%. The yield of OTP was 65.22% then.