Toluene Alkylation Catalysts For 2,6-DMN Synthesis

2,6-DMN is an important monomer for poly naphthalene two formic acid glycol ester with good performance. There are three industrial routes for the synthesis of 2,6-DMN: Side-chain xylene alkylation using o-xylene/butadiene; or p-xylene/butadiene as raw materials and toluene alkylation with pentene. Compared with side-chain xylene alkylation, toluene alkylation process has the advantages such as low requirement for raw materials and available catalytic material. As a result, it was taken to be the main research task in this study.The first step for synthesis of 2,6-DMN from toluene and pentene was investigated. We obtained two catalysts, including MOR zeolite treated by 0.05-0.2 mol/L HCl or 0.1-0.4 mol/L NaOH solutions and BEA nano-zeolite with Si/Al ratio of 10-85. The structure of these catalysts was studied by XRD, SEM, ICP. BET. NH3-TPD and TEM. The performance was evaluated by toluene alkylation with pentene.The crystallinity, particle size, Si/Al ratio, acid strength, pore structure as well as the reaction performance were changed after treatment, The toluene conversion reached more than 10% for the treated catalysts with 0.2 mol/L alkali or below 0.1 mol/L acid solutions. The pentene conversion and product selectivity was more than 60% and 90%, respectively. BEA zeolite with Si/Al ration of 25, size of 80 nm was derive via the solution of SiO2:Al2O3:OH-1:TEA+:Na+:F-1:Br-1= (20-100):1:28:23:1.5:0.01:1.4. The Si/Al ration of obtained zeolite was lower than that of sol, about 85% to the sol solution. The catalyst molded the zeolite and alumina with weight ratio of 8:2 possessed good performance., which could improve after loading 0.03% Pt or Pd.The effect of reaction condition was also studied. The pentene conversion, toluene conversion and selectivity were beyond 95%,15% and 95%, respectively, with molar ratio of toluene and pentene of 4:1 in batch reactor after 0.5 h or in 2.0 h-1 flow reactor.The amyl alcohol also could be used as reagent in toluene alkylation. Based on β and Y zeolite catalysts in batch reactor, the amyl alcohol converstion, toluene conversion and product selectivity were approach to 90%,20% and 90%, respectively. Meanwhile, amyl alcohol could dehydrate to 1-pentene and its isomers, which could be used as alkylation reagent. With the alcohol; dehydration catalyst from SRIPT, the amyl alcoholconversion was beyond 95%, and the selectivity was beyond 90%. The life period of the catalyst was more than 1 month under the reaction conditions of 300℃, 0.01MPa and 0.8-1 h.