Fatih GÜLEÇ, Ali KARADUMAN, Emir HÜSEYİN ŞİMŞEK

Zr/ZSM5 zeolit katalizörleri varlığında 2-metil naftalinin disproporsiyon kinetiği

HZSM5 ve Zr/ZSM5 zeolit katalizörleri üzerinde 2-metil naftalinin disproporsiyonu ile 2,6-dimetil naftalin sentezi ve reaksiyon kinetiği araştırılmıştır. Zr/ZSM5 zeolit katalizörleri ıslak emdirme yöntemiyle hazırlanmıştır. Disproporsiyon deneyleri, diferansiyel gaz-katı katalitik sabit yatak reaktörde, 2 ml katalizör varlığında, iki farklı sıcaklık ve beş farklı boşluk hızında gerçekleştirilmiştir. Mol oranı 1:1 olan 2-metil naftalin ve benzen karışımı besleme olarak kullanılmıştır. Reaktör çıkışındaki gaz ürünler, ceket kısmından etilen glikol sirküle edilen bir soğutucuda yoğunlaştırılmıştır. Sıvı ürünler GC-MS cihazı kullanılarak tanımlanmıştır. Sonuçlar, 2,6-dimetil naftalinin yanında diğer dimetil naftalin ve trimetil naftalin izomerlerinin de oluştuğunu göstermiştir. 2-Metil naftalin dönüşümü sıcaklık artışıyla artmış, boşluk hızı artışı ile azalmıştır. 2-Metil naftalinin en yüksek dönüşümü HZSM5 katalizörü üzerinde %30,4 ve Zr/ZSM katalizörü üzerinde %22,1dir. 2,6-DMN/2,7-DMN oranı her iki katalizör içinde 1,0 değerinin üzerinde çıkmıştır. ZSM5 yapısına Zr metalinin emdirilmesiyle hem 2,6-dimetil naftalin seçimliliği hem de 2,6-dimetil naftalin verimi, düşük sıcaklıkta azalmasına rağmen yüksek sıcaklıkta artmıştır. HZSM5 katalizörü kullanılarak ulaşılan en yüksek 2,6-DMN seçimliliği %38,2, en yüksek 2,6-DMN verimi %2,4 iken Zr/ZSM5 katalizörü kullanılarak ulaşılan en yüksek 2,6-DMN seçimliliği %42,4, en yüksek 2,6-DMN verimi ise %4,1 dir.2-Metil naftalinin disproporsiyon kinetik denklemi HZSM5 ve Zr/ZSM5 katalizörleri varlığında 2. mertebe bulunmuştur

Disproportionation kinetics of 2-methylnaphthalene in the presence of Zr/ZSM5 zeolite catalysts

Synthesis of 2,6-dimethylnaphthalene and reaction kinetics were investigated with disproportionation of 2methylnaphthalene over HZSM5 and Zr/ZSM5 zeolite catalysts. The Zr/ZSM5 zeolite catalysts were prepared by wet impregnation method. The disproportionation experiments were carried in a differential gas-solid catalytic fixed bed reactor in the presence of 2 ml catalysts at two different temperature and five different weight hourly space velocity.2-methylnaphthalene and benzene mixture which had a mole ratio of 1:1 was used as a feed.The gas products, which exited from the reactor, were condensed in a cooler where ethylene glycol was circulated. The liquid products were identified by using GC-MS instrument.The results were shown that besides 2,6-dimethylnaphthalene, other dimethylnaphthalene and trimethylnaphthalene isomers were formed. Conversion of 2-methylnaphthalene was increased with increasing temperature and it was decreased with increasing weight hourly space velocity. The highest conversion of 2-methylnaphthalene was 30.4% over HZSM5 and 22.1% over Zr/ZSM5. Ratio of 2,6dimethylnaphthalene/2,7-dimethylnaphthalene was above 1.0 for both zeolite catalysts. Although both selectivity of 2,6-dimethylnaphthalene and yield of 2,6-dimethylnaphthalene were decreased at lower temperature, they were increased at high temperature with Zr impregnated on ZSM5 structure. While the highest selectivity of 2,6-dimethylnaphthalene was reached 38.2% and the highest yield of 2,6dimethylnaphthalene was reached 2.4 using HZSM5, the highest selectivity of 2,6-dimethyl naphthalene was reached 42.4% and the highest yield of 2,6-dimethyl naphthalene was reached 4.1 using Zr/ZSM5 catalyst. The disproportionation kinetic equation of 2-methylnaphthalene was found 2 order in the presence of HZSM5 and Zr/ZSM5 catalyst

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