Methylation of Coal Tar Naphthalene Oil Fractions to Increase Amount of Dimethylnaphthalenes using Au-Beta ZeoliteCatalysts
FatihGüleç,AysunÖzen, Ali Karaduman*
Ankara University, Engineering Faculty, Dept. of Chemical Engineering 06100 Ankara, TURKEY
Abstract for oral presentation
Synthesis of 2,6-Dimethylnaphthalene is very important step for Polyethylene naphthalate production which is an alternative polymer to the Polyethylene terephthalate because of its better features such as oligomer extraction, tensile strength, young’s modulus, radiation resistance, UV absorbance and glass transition temperature.Generally, Dimethylnaphthalenescan be produced with methylation of 2-methylnaphthalene and naphthalene. Because of the wealthy naphthalene content, Coal Tar Naphthalene Oil Fraction is very significant source to production of Mono-, Di-, Tri-Methylnaphthalenes. In the literature, production of 2,6-Dimethylnaphthalene is being tested with various catalysts. Zeolite type catalysts are prominent in these catalysts, due to their porous structure, ion exchange capacity and high surface area. However most of them are focused on increasing selectivity of 2,6-Dimethylnaphthalene, conversion of 2-Methylnaphthaene and ratio of 2,6-Dimethylnaphthalene/2,7-Dimethylnaphthalene, a desired values and an economic process have not been developed on production of 2,6-Dimethylnaphthalene yet.
In this study, the methylationof Coal Tar Naphthalene Oil Fraction with methanol over Audoped Beta zeolite catalysts which was calcined at 550 °C and 750 °C for 7h were investigated in a fixed bed reactor operating at atmospheric pressure.The reactor was operated at 400 °Cand the Weight Hourly Space Velocity of the total reaction feed was 2 h-1 in all experiments.The obtained reaction products were analyzed by using GC-MS system with 60 meters capillary column. Conversion of 2-Methylnaphthalene, ratio of 2-Methylnaphthalene/1-Methylnaphthalene,selectivity of 2,6-Dimethylnaphthalene and Dimethylnaphthalenes, distribution of Dimethylnaphthalenes,mass percent of naphthalenewere determined.
Additionally, specific surface area of the synthesized catalysts was calculated from N2 adsorption isotherms using a Quantachrome NOVA 2200 instrument. Pore size distributions of the catalysts were measured using the same gas adsorption instrument operating at liquid nitrogen temperature. The amount of doped metals and the ratio of Si/Al were analyzed with Spectro XLAB-2000 PEDX-ray fluorescence spectrometer. The IR analyses were carried out using a Mattson 1000 FT-IR spectrometer. The morphology of zeolite was imaged by SEM using a ZEISS EVO 40 microscope.
Keywords: Beta zeolite, naphthalene derivatives, 2,6-Dimethylnaphthalene, Methylation, PEN.
Acknowledgements: We are thankful and greatfully appreciate Ankara University Scientific Research Projects Departmentfor the support of this work. (Project No: 15B0443009)
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