A Comparative Characterization of the HPA‐MCM‐48 Type Catalysts Produced by the Direct Hydrothermal and Room Temperature Synthesis Methods

Güçbilmez, Yeşim; Yargıç, Adife Şeyda; Çalış, İbrahim

doi:10.1155/2012/210437

Cited by 6 publications

(6 citation statements)

References 49 publications

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“…Experimental conditions were as follows: catalyst to oil weight ratio, 1.5%; MeOH to oil volume ratio, 2:1; temperature, 70°C; reaction time, 3h; Feed, 10g; n/a It was found that the room temperature synthesis method resulted in catalysts with higher crystallinity, higher surface area and pore volume and were more economical. (Gucbilmez et al, 2012) PTA supported on MCM 41 esterification of acetic acid with noctanol MCM 41 could take higher loadings of up to 71% but optimal values were obtained at 60% i.e. surface acidity was maximized at this loading.…”

Section: Discussionmentioning

confidence: 99%

“…It is assumed that fatty acid neutralization might be the reason for the loss in yield. Studies conducted on other mesoporous materials such as SBA-15 and MCM-41 have reported similar yield when other oils were used as feedstock (Brahmkhatri and Patel, 2011;Gucbilmez et al, 2012). 12phosphotungstic acid (PTA) impregnated on four supports namely silica, alumina, hydrous zirconia, and activated carbon were used for the production of biodiesel from low quality canola oil which contained up to 20 wt% FFA.…”

Section: Conversion and Yieldmentioning

confidence: 99%

“…HPAs are very strong Brönsted acids that are comparable to or stronger than conventional acids such as HCl, H 2 SO 4 , HClO 4 , zeolites and acidic resins (Zhang et al, 2010). Despite these advantages HPAs have very low surface area <10 m 2 /g in solid state and are essentially of low porosity with very few acid sites available for reaction with hydrocarbons (Gucbilmez et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Conversion of a variety of high free fatty acid containing feedstock to biodiesel using solid acid supported catalyst

Bala

Souza

Misra

et al. 2015

Journal of Cleaner Production

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The present study explores the use of silicotungstic acid anchored to mesoporous siliceous support, KIT-6, as a catalyst to produce biodiesel. Silicotungstic acid loaded KIT-6 was synthesized and the physicochemical properties were characterized using scanning electron microscopy, surface area and pore size distribution analyzer, Fourier transform infrared spectroscopy, X-ray diffraction, Xray photoelectron spectroscopy and inductively coupled plasmaoptical emission spectroscopy techniques. Efficiency of the silicotungstic acid loaded KIT-6 in the production of biodiesel from a variety of high free fatty acid containing feedstock was then evaluated. The composition of free fatty acids in all the feedstock oils (algae oil, coffee oil, palmitic acid and used cooking oil) and their biodiesel resulting from the feedstock were also analyzed. Compared with other solid acid catalysts, the resulting materials show stable and highly efficient catalytic performance in biodiesel production with the highest conversion reaching 99%. A sample containing 26 wt% of silicotungstic acid supported on KIT-6 was found to be the most active catalyst for esterification at 70 °C whilst stirring constantly, with an alcohol/acid volume ratio of 2 and 1.5 wt% loading catalyst for 3 h. Furthermore, the catalyst was reused for four cycles indicating recyclability of the catalyst.

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Section: Discussionmentioning

confidence: 99%

Section: Conversion and Yieldmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Conversion of a variety of high free fatty acid containing feedstock to biodiesel using solid acid supported catalyst

Bala

Souza

Misra

et al. 2015

Journal of Cleaner Production

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show abstract

“…[34,35] In contrast to natural molecular sieves (zeolites), the M41S structures exhibit interesting properties, such as higher surface areas (up to 1600 m 2 /g), higher pore volumes (up to 1.2 cm 3 /g), and pore sizes in the mesoporous range (2-10 nm). [36] These properties have made the M41S family structures the subject of several studies on a wide range of applications in adsorption and separation industrial processes and also in catalysis and biomedicine. [37] F I G U R E 1 Proposed pathways to obtain mono-and bicyclic terpenes from acidic isomerization of pinenes However, the most remarkable feature of this family of materials is its well-ordered pore system, composed of a uniform shape and narrow size distribution.…”

Section: Introductionmentioning

confidence: 99%

Heterogeneous catalyzed isomerization of turpentine oil by ordered mesoporous materials like M41S structures

et al. 2022

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Herein, the synthesis of a structure with a porous system similar to that of molecular sieves, MCM‐41 and 48 types, with the incorporation of heteroatoms in their synthesis, is reported. The catalytic activity of these materials was tested in the isomerization reaction of turpentine oil to obtain camphene. The best results were obtained with Zn‐Al‐Si‐MCM, a mesoporous material, with a conversion of up to 96% and selectivities of 31% and 22% to camphene and 4‐carene, respectively, both of which are bicyclic products. The recycling of the catalyst was also tested, and after three cycles, no significant loss of activity was observed.

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“…Heteropoly acids (HPAs) are complex proton acids that incorporate polyoxometalate anions (heteropoly anions) having metal-oxygen octahedra as the basic structural units. HPAs have several advantages such as very strong Brönsted acidities approaching the super acid region [6] and high oxidant activities in multielectron redox reactions under mild conditions. Their acid-base and redox properties can be varied widely by changing their chemical compositions.…”

Section: Introductionmentioning

confidence: 99%

Dehydrocyclization of n-Hexane over Heteropolyoxometalates Catalysts

Eid¹,

Benlounes²,

Hilal³

et al. 2013

ACES

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The catalytic dehydrocyclization of n-hexane was studied here for the first time using a number of compounds based on H₃PMo₁₂O₄₀. The described catalystswere prepared by either replacing the acidic proton with counter-ions such as ammonium or transition metal cations (NH₄⁺, Fe³⁺, K⁺), or by replacing Mo⁶⁺ with (Ni³⁺, Co³⁺, Mn³⁺) in the polyoxometalate framework, as reported earlier. For comparison purposes, the known (TBA)₇PW₁₁O₃₉ catalyst system was used. All reactions were conducted at different temperatures in the range 200 - 450. The Keggin structure of these heteropolycompounds was ascertained by XRD, UV and IR measurements. ³¹P NMR measurements and thermal behaviour of the prepared catalystswere also studied. These modified polyoxometalates exhibited heterogeneous superacidic catalytic activities in dehydrocyclization of n-hexane into benzene, cyclohexane, cyclohexene and cyclohexadiene. The catalysts obtained by substituting the acidic proton or coordination atom exhibited higher selectivity and stability than the parent compound H₃PMo₁₂O₄₀. Catalytic activity and selectivity were heavily dependent on the composition of the catalyst and on the reaction conditions. At higher temperatures, the catalyst exhibited higher conversion efficiency at the expense of selectivity. Using higher temperatures (>400) in the presence of hydrogen carrier gas, selectivity towards dehydrocyclization ceased and methane dominated. To explain the results, a plausible mechanism is presented, based on super-acidic nature of the catalyst systems.

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A Comparative Characterization of the HPA‐MCM‐48 Type Catalysts Produced by the Direct Hydrothermal and Room Temperature Synthesis Methods

Cited by 6 publications

References 49 publications

Conversion of a variety of high free fatty acid containing feedstock to biodiesel using solid acid supported catalyst

Conversion of a variety of high free fatty acid containing feedstock to biodiesel using solid acid supported catalyst

Heterogeneous catalyzed isomerization of turpentine oil by ordered mesoporous materials like M41S structures

Dehydrocyclization of n-Hexane over Heteropolyoxometalates Catalysts

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