Şekil 2’de Pt/mordenit zeolit katalizörünün SEM görüntüsün gösterilmektedir ve görüldüğü üzere katalizör homojen bir morfolojiye sahiptir. Yüzey alanı, katalitik aktivitede önemli bir rol oynamaktadır. Yüzey alanı, yüksekse reaktanlar daha iyi adsorbe edilir. Katalizörün yüzey alanı, BET yüzey analiziyle ölçülmüştür. Pt/mordenit zeolitlerinin yüzey alanı 296.69 m2/g olarak ölçülmüştür. Pt/mordenit zeolitin XRD deseni (Şekil 3), 2θ = 6 ° – 30 °'de en yoğun kırınım şiddetine sahiptir; böylece zeolitin MOR yapısı ve iyi kristal yapısı doğrulanmıştır.
Pentan izomerlerinden oluşan ikili bir karışımda saf n-pentan ve n-pentanın hidroizomerizasyonu, Pt/mordenit katalizörü kullanılarak çok çeşitli deneysel koşullar altında gerçekleştirilmiştir. Hidro dönüşüm ürünleri hem izomerleştirme hem de kraking ürünlerini ihtiva eder. Aşağıdaki alt bölümlerde, reaksiyon parametrelerinin besleme maddesi kullanılan saf n-pentanın katalitik performansını nasıl etkilediği açıklanmakta ve katalitik aktivite ve izomerizasyon seçiciliği üzerinden gösterilmektedir. Sonrasında ise ikili karışımdaki n-pentanın izomerizasyonu açıklanmaktadır.
Şekil 4’te reaksiyon sıcaklığının bir fonksiyonu olarak n-pentanın dönüşümü gösterilmektedir. Reaksiyonlar, atmosfer basıncında 150 °C ila 350 °C arasında değişen sıcaklıklarda bir H2 ortamında gerçekleştirilmiştir. Katalizörün, özellikle 220 °C ila 350 °C arasındaki sıcaklıklarda, n-pentanın izomerizasyonunu güçlü bir şekilde katalize ettiği görülmektedir. Katalizörün düşük aktivitesi ve n-pentanın düşük reaktivitesinden dolayı, 180 ° C'nin altındaki sıcaklıklarda n-pentanın dönüşümü ihmal edilebilir. Sıcaklık 180 °C'den 220 °C'ye yükseltildiğinde n-pentanın dönüşümü büyük ölçüde artmıştır; ancak, sıcaklığın daha da arttırılması dönüşümün yavaşlamasına yol açmıştır. Bu durum, sıcaklık 180 °C – 220 °C aralığına çıktığında reaksiyon için etkinleştirilebilecek alanların sayısının artmasından kaynaklanmış olabilir; ancak, yüksek sıcaklıkta termodinamik kısıtlamalar nedeniyle artan sıcaklığa karşılık dönüşüm oranı düşmeye başlar. Diğer bir ifadeyle, sıcaklığın arttırılması her zaman daha yüksek bir reaksiyon hızıyla sonuçlanır. Düşük sıcaklıkta, gerçek dönüşüm, düşük reaksiyon hızı nedeniyle denge dönüşümünün çok altında olacaktır. Buna karşılık, daha yüksek sıcaklıkta, yüksek reaksiyon hızı nedeniyle denge dönüşümü daha kolay olacaktır.
Figure 2shows anAn SEM image of the Pt/mordenitezeolite catalyst. The image is shown in Figure 2 and indicatesthat thecatalyst has a homogeneous morphology. The surface area isplays akey rolein the catalystcatalyticactivity. HigherHigh surface areaimproves the reactant adsorption. ofreactants. The catalysts surface area of thecatalyst was measured by BET. surface analysis.1 The surface area of Pt/mordneite2mordenitezeolites were 296.69 m2/gm. The XRDsXRDpattern of Pt/mordenite zeolite (Figure 3) exhibits the most intensediffraction peaks at 2θ = 6 - 30o, and it thusconfirmed 30othe MOR structure ofzeolite asthe MOR as well asand its good crystallinenature beinggood. are thus confirmed.3
The hydroisomerizationof pure n-pentane and n-pentane in a binary mixture of pentane isomers wasperformed by the Pt/mordenite catalyst forunder awide rangesrangeof experimental conditions. The hydrological hydro-4conversionproducts comprise of both isomerization and cracking products. Hence theThefollowing subsections discuss cover how the reactionparameters effects withaffect thecatalytic performance of pure n-pentane as the feed are, which isdemonstrated by catalytic activity and isomerization selectivity.5 After thisThen,the isomerization of n-pentane in the bibinarymixture is discussed in the last part of this section6.
Figure 4 showsthe conversion of npentane as a function of reaction temperature. The testsreactions7were performed in an H2 environment at temperatures ranging from 150- 350 °C at atmosphere pressures. It clearly shows that the catalyst showed ahigh catalysing activity for the isomerization of npentane,particularly in the temperature ranging inrange of 220-350° C. Because of the low activity of the catalyst and the low reactivity ofn-pentane, the conversion of n-pentane is negligible from temperatures below180 °C. By increasing the temperature at 180 to 220 °C, the conversion ofn-pentane roseincreased greatly;however, a further increase in increasingthe temperature slowly risesfurther results in a slow8conversion. This can be caused by an increasing the number of siteswhich can be activated for the reaction when the temperatures increases in therange from 180 - 220 °C; but, the rate of conversion decreases because ofthermodynamic restriction at bigger temperature. In other words, an increasingthe temperaturealways meansincreasingresults in a higher reaction rate.Thus at low temperatures, the actual conversion will be farbelow the equilibrium conversion because of low reaction rate. On the contraryat higher temperatures the equilibrium conversion will be more easy due to a highreaction rate.
Figure 2shows anAn SEMA scanning electron microscopy1 image of thePt/mordenite zeolite catalyst. The image is shown in Figure 2and which indicatesthat thecatalyst has a homogeneous morphology. The surface area plays a key role in the catalyticactivity. is homogeneousHigher.Highsurface area improves the reactant adsorption, of reactants. thus playing a key role in the catalytic activity2. The catalysts surfacearea ofthe Pt/mordenitezeolite3 catalyst was4 measured by BET.Brunauer–Emmett–Teller surface analysis5. Thesurface area of Pt/was 296.69 m2/gmordneitemordenite zeoliteswerem6.The XRDX-raypowder diffraction pattern of Pt/mordenite zeolite (Figure 3)exhibits the most intense diffraction peaks at 2θ = 6 - 30o,and it thus confirmed 6°–30o7, thus confirming the MOR structure ofzeolite asthe MOR as well as and its good crystallinenature beinggood. are thus confirmed.8
Thehydroisomerization of pure Pure n-pentane andn-pentane in a binary mixture of pentane isomers was performed byhydroisomerized usingthe Pt/mordenite catalyst forunder a wide rangesrangeof experimental conditions. The hydrological hydro-conversion9 products comprise ofprocessyielded both isomerization and cracking products. Hence theThe In the followingsubsections, discuss cover howthe effects of reaction parameters effects with10affect on thecatalytic performance of pure n-pentane as the feed are which is demonstratedbybased oncatalytic activity and isomerization selectivity. 11After thisThen,the isomerization of n-pentane in the bibinarymixture is discussed in the last part of this section.12
Figure 4 showsthe conversion of npentane n-pentane13 as a function ofreaction temperature. The testsreactions14 wereperformed in an H2 environment at temperatures ranging from 150 °C to 350 °C at atmospherepressures. It clearly shows that theatmospheric pressure. The catalyst showeda high catalysing activity for the isseen to strongly catalyze the isomerization of npentanen-pentane, particularlyin the temperature ranging inrange of 220 °C-350 °C. Because of the low activity of thecatalyst and the low reactivity of n-pentane, the conversion of n-pentane isnegligible from at temperatures below 180 °C. By increasing thetemperature at from180 °C to 220 °C, theconversion of n-pentane roseincreased greatlysignificantly;however, a further increase in increasingthe temperature slowly risesfurther results in a slowconversion.15 This can be caused by attributed to an increase inthe number of sites anincreasingwhich that can be activated for the reaction when thetemperatures increases in the range from 180 °C- 220 °C; buthowever,the rate ofconversion decreases ratebegins to decrease as the temperature increases because ofthermodynamic restrictions at bigger higher temperatures. In other words, an increasing the temperaturealways means increasingresults in ahigherfaster reaction rate. ThusatAt low temperatures,the low reaction rates cause the actualconversion will to be far below the equilibrium conversion because of low reaction rate. On the contraryIncontrast at higher temperatures theequilibrium conversion will be more easyis easily achieved due to a the highreaction rate.
A scanning electron microscopy image of the Pt/mordenite zeolite catalyst is shown in Figure 2 which indicates that the catalyst morphology is homogeneous .High surface area improves the reactant adsorption, thus playing a key role in the catalytic activity . The surface area of the Pt/mordenite zeolite catalyst measured by Brunauer–Emmett–Teller surface analysis.was 296.69 m2/g. The X-ray powder diffraction pattern of Pt/mordenite zeolite (Figure 3) exhibits the most intense diffraction peaks at 2θ = 6°–30°, thus confirming the MOR structure of zeolite as well as its good crystalline nature .
Pure n-pentane and n-pentane in a binary mixture of pentane isomers was hydroisomerized using the Pt/mordenite catalyst under a wide range of experimental conditions. The hydro-conversion process yielded both isomerization and cracking products. In the following subsections, the effects of reaction parameters on the catalytic performance of pure n-pentane as the feed are demonstrated based on catalytic activity and isomerization selectivity. Then, the isomerization of n-pentane in the binary mixture is discussed in the last part of this section.
Figure 4 shows the conversion of n-pentane as a function of reaction temperature. The reactions were performed in an H2 environment at temperatures ranging from 150 °C to 350 °C at at atmospheric pressure. The catalyst is seen to strongly catalyze the isomerization of n-pentane, particularly in the temperature range of 220 °C–350 °C. Because of the low activity of the catalyst and the low reactivity of n-pentane, the conversion of n-pentane is negligible at temperatures below 180 °C. By increasing the temperature from 180 °C to 220 °C, the conversion of n-pentane increased significantly; however, increasing the temperature further results in a slow conversion. This can be attributed to an increase in the number of sites that can be activated for the reaction when the temperatures increases in the range from 180 - 220 °C; however, the r conversion rate begins to decrease as the temperature increases because of thermodynamic restrictions at higher temperatures. In other words, increasing the temperature results in a faster reaction rate. At low temperatures, the low reaction rates cause the actual conversion to be far below the equilibrium conversion rate. In contrast at higher temperatures the equilibrium conversion is easily achieved due to the high reaction rate.
