Comportamiento de Catalizadores PtMo/g-Al2O3-B2O3 en Reacciones de Hidrodesaromatización de Naftaleno e Hidrodesulfuración de Dibenzotiofeno

Baldovino-Medrano, Víctor G.; Giraldo, Sonia A.; Centeno, Aristóbulo

doi:10.4067/s0718-07642009000600002

Cited by 4 publications

(14 citation statements)

References 22 publications

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“…It is demonstrated that the above method of analysis fruitfully leads to better interpretation and advances in our knowledge of the structure of nanoporous materials. On the other hand, the strategies for the analysis presented in this paper seem particularly handy when dealing with materials that exhibit both micropores and mesopores, a type of materials often found in many scientific and industrial applications. − ,,,,− …”

Section: Introductionmentioning

confidence: 99%

“…In this contribution, a critical assessment of the nitrogen adsorption–desorption isotherms of a series of materials based on amorphous aluminosilicates and of the data thereof derived to characterize their texture is done. The amorphous aluminosilicates were synthesized with three methods: sol–gel via hydrolysis in acidic medium (ACSG), , sol–gel with a poly(ethylene glycol) (PEG) template (P), , and sol–gel with gel skeletal reinforcement (GRS). ,, All of these methods have proven to produce materials with different textures, namely, surface area (SA) and porosity. − This property has made them interesting for catalytic applications either as standalone materials or as carriers for metallic catalytic phases of particular interest for hydrocracking processes. − Besides specific procedures of the synthesis method, it is known that the Si/(Si + Al) molar ratio of the aluminosilicates and the loading of metallic phases may affect their texture. ,,,− Herein, we particularly loaded the synthesized amorphous aluminosilicates with nickel and molybdenum oxide by wet impregnation. , These materials are normally applied for hydroprocessing reactions. ,, …”

Section: Introductionmentioning

confidence: 99%

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Systematic Analysis of the Nitrogen Adsorption–Desorption Isotherms Recorded for a Series of Materials Based on Microporous–Mesoporous Amorphous Aluminosilicates Using Classical Methods

Baldovino-Medrano,

Niño-Celis,

Isaacs Giraldo

2023

J. Chem. Eng. Data

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Amorphous aluminosilicates are applied in adsorption and catalysis because they can be designed to possess micro-, meso-, and macropores. In this work, we analyze the nitrogen physisorption isotherms recorded for a series of materials based on amorphous aluminosilicates synthesized by sol−gel via hydrolysis in acidic medium (ACSG), sol−gel with a poly(ethylene glycol) template (P), and sol−gel with gel skeletal reinforcement (GRS). We found that the porosity of the ACGS and GRS types of materials was dominated by mesopores, while that of the P-type materials was dominated by micropores but with a non-negligible fraction of mesopores. We catalogued the isotherms produced by the latter type of materials as type IV(c) as a supplement to the current IUPAC classification. In addition, we found that the hysteresis loops shown by the amorphous aluminosilicates of the ACGS-type materials present inflection points not found in the current IUPAC classes; therefore, we propose classifying them as H3(b) types. We also assessed the surface area and porosity of the materials by classical methods, namely, the Brunauer−Emmett−Teller (BET) surface area, t-plot microporosity, Barrett−Joyner− Halenda (BJH) mesopore size distribution, and fractal dimension. First, we found a semiexponential correlation between the C BET constant of the materials and their relative fraction of the microporous surface area. Second, we found that under the conditions used herein, the impregnation of a NiMo phase over the synthesized amorphous aluminosilicates increased the C BET constant and reduced the fractal dimension of the materials. These changes were thus correlated to the changes observed in the relative microporosity and mesoporous size distributions of the materials.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Systematic Analysis of the Nitrogen Adsorption–Desorption Isotherms Recorded for a Series of Materials Based on Microporous–Mesoporous Amorphous Aluminosilicates Using Classical Methods

Baldovino-Medrano,

Niño-Celis,

Isaacs Giraldo

2023

J. Chem. Eng. Data

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“…One is the direct desulfurization (DDS) route and the other is mediated by the hydrogenation of one of the aromatic rings (HYD) of the molecule before the breakage of its C-S bond. [16,18,19,[21][22][23][24][25][26] The direct desulfurization of dibenzothiophene is kinetically dominant over conventional -Al2O3 supported Ni-MoS2 and Co-MoS2 catalysts and even over unconventional noble metal promoted MoS2 catalysts. [26][27][28][29][30][31][32][33][34][35] Accordingly, it is generally agreed that MoS2 is the active phase of the catalysts and that secondary metals such as Ni, Co, and even noble metals essentially act as promoters of the MoS2.…”

Section: Introductionmentioning

confidence: 99%

Catalytic performance of supported Ni in the hydrodesulfurization of dibenzothiophene

Valderrama-Zapata,

García-Sánchez,

Vargas-Montañez

et al. 2023

Preprint

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To reduce pollution, sulfur, nitrogen, and other heteroatoms are removed from fuels by hydrotreatment (HDT). Conventional HDT catalysts are based on Ni-MoS2 phases dispersed over -Al2O3. Despite the myriad of papers studying these catalysts, it is somehow surprising to learn that the role of Ni in these catalysts is not yet fully understood. Most literature considers that Ni is either converted to some form of catalytically inactive nickel sulfide or that it mixes with MoS2 to act as a strong catalytic promoter. In this work, we focused on analyzing whether well-dispersed supported nickel nanoparticles can be active in the hydrodesulfurization of dibenzothiophene; one of the most refractory molecules composing diesel and marine fuels. We dispersed nickel using the principles of the strong electrostatic adsorption (SEA) method over silica (~neutral acidity), Al2O3 (Lewis acidity), H+-Y zeolite (Brönsted-Lewis acidity), and microporous-mesoporous H+-Y zeolite (similar Brönsted-Lewis acidity than its microporous counterpart). The results showed that Ni nanoparticles are catalytically active in the hydrodesulfurization of DBT and that zeolites provide them with long-term stability. In addition, using SEA impregnation and providing mesoporosity to the zeolite improved the catalytic performance. Overall, we demonstrate that Ni nanoparticles may behave in the same manner as noble metals such as Pt, Pd, and Ir behave in hydrodesulfurization. We discuss some of the probable reasons for such behavior and remark on the role of Ni in hydrotreatment.

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“…The strategies for analysis presented in the paper seem particularly handy when dealing with materials that exhibit both micropores and mesopores; a type of materials often found in many scientific and industrial applications. 19,35,36,[38][39][40][41][42][43][44][45][46][47][48] 2. Experimental and analytical methods 2.1 Analyzed materials.…”

Section: Introductionmentioning

confidence: 99%

“…Further impregnation of a Ni-MoOx phase was made to these amorphous silica-aluminas (NiMo) whose primary application was the refining of heavy crude oil cuts. 44,45 Specific details for the synthesis of the materials are reported by Coconubo 36 and Duarte. 35 For the purposes of the current work, the materials were branded as ASA###, ASAP##, ASAR###, and NiMo/ASA###, NiMo/ASAP##, and NiMo/ASAR###.…”

Section: Introductionmentioning

confidence: 99%

Systematic analysis of the nitrogen adsorption-desorption isotherms recorded for a series of microporous – mesoporous amorphous aluminosilicates using classical methods

Medrano

Celis

Giraldo

2022

Preprint

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Understanding the porous structure of microporous – mesoporous materials is very important for developing useful scientific concepts and principles in materials science, surface science, heterogeneous catalysis, adsorption and related technological applications. Amorphous aluminosilicates are of particular interest in this sense because it is relatively simple to design them with diverse porous structures comprising micro, meso, and even macropores. In this work, we took advantage of the latter and developed a systematic and in-depth analysis of the results of nitrogen physisorption tests at 77 K performed over a series of microporous – mesoporous amorphous aluminosilicates and of the characterization of their texture by classical models to estimate surface area and porosity. The strategy for the analysis consisted of making a thorough description of the features showed by the recorded nitrogen isotherms, first. As a result, a proposal for considering two new types of isotherms, types I(c) and IV(c), and five new types of hysteresis loops, H1(b), H2(c), H3(b), H3(c), and H4(b), in addition to the standard IUPAC classification. These new categories stemmed from the microporous – mesoporous nature of the materials and from the presence of strong network effects. The previous analysis helped interpreting and judging the results of the calculations made with classical methods to assess the texture of the materials; namely, their BET surface area, t-plot microporosity, BJH mesopore size distribution, and fractal dimension. The performed analyses allowed establishing that the relative percentage of microporosity of the materials can be correlated to the physisorption energy as described qualitatively by the CBET constant. Concerning mesopore size distributions, it was found that the BJH method remains to be very valuable for describing the porous structure of the materials particularly if the results obtained with both branches of the isotherms are considered. Finally, it was shown that the fractal dimension can complement the analysis of the porous structure of microporous – mesoporous materials if the latter are compared considering the features of their isotherms and of their hysteresis loops. Overall, the present study can thus be said to make two contributions: (i) it proposes a systematic methodology for analyzing both the raw data and the textural properties calculated by classical methods both derived from nitrogen physisorption experiments. (ii) It presents useful new insights on the texture of microporous – mesoporous materials.

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Comportamiento de Catalizadores PtMo/g-Al2O3-B2O3 en Reacciones de Hidrodesaromatización de Naftaleno e Hidrodesulfuración de Dibenzotiofeno

Cited by 4 publications

References 22 publications

Systematic Analysis of the Nitrogen Adsorption–Desorption Isotherms Recorded for a Series of Materials Based on Microporous–Mesoporous Amorphous Aluminosilicates Using Classical Methods

Systematic Analysis of the Nitrogen Adsorption–Desorption Isotherms Recorded for a Series of Materials Based on Microporous–Mesoporous Amorphous Aluminosilicates Using Classical Methods

Catalytic performance of supported Ni in the hydrodesulfurization of dibenzothiophene

Systematic analysis of the nitrogen adsorption-desorption isotherms recorded for a series of microporous – mesoporous amorphous aluminosilicates using classical methods

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