Amount Of Acid Sites Research Articles

Effective synthesis of limonene over mild alkali-modified 13X catalysts in α-pinene isomerization

The mild alkali-treated 13X was employed in the liquid phase isomerization reaction of α-pinene to increase the yield of limonene. A maximum α-pinene conversion of 100% and limonene yield of 59.1% could be achieved. Crystallinity could be well retained, and the amounts of medium-strong acid sites and the distribution of Brønsted and Lewis acid sites could be changed after the mild alkali treatment for 13X zeolite. Samples with higher micropore specific surface area were easier to obtain higher yields of limonene due to shape-selectivity. A proper amount of the medium-strong acid and the synergistic effect of Brønsted and Lewis acid sites were beneficial to enhance the catalytic activity and the yield of monocyclic product limonene. The main reason for catalyst deactivation could be the decrease in the active sites due to soft coke deposition. For the regeneration process, the conversions of α-pinene were between 95% and 99% during the first seven cycles and the conversion dropped to 90.6% after the eighth cycle, which demonstrated that the ethanol flushing and calcination could be an effective regeneration method for the 13X catalyst used in the α-pinene isomerization reaction.

Tailoring the impact of synthetic strategies on the catalytic upgrading of crude glycerol to produce bio-based aromatics in hierarchical HZSM-5

The catalytic upgrading of renewable biomass derived crude glycerol to generate bio-based aromatics is a promising alternative to petroleum route for the synthesis of valuable and versatile aromatics. The effects of synthetic strategies on the physicochemical property of hierarchical HZSM-5 as well as their corresponding catalytic upgrading performances of crude glycerol to bio-based aromatics were systematically investigated in this work. HZSM-5/0.3M NaOH catalyst exhibited smaller improvement in aromatic yields than microporous HZSM-5, which could be ascribed to the uncontrollable large intra-mesopore diameter and less increment in the amounts of acid sites during the introduction of mesoporosity via destructive alkali treatment. The soft templated HZSM-5/TPOAC catalyst produced more BTX and C9+ monocyclic aromatics, which could be attributed to its larger crystal sizes, higher external surfaces, luxuriant L acid amounts, uniform and small mesopore sizes. However, the hard templated HZSM-5/CNT-OH catalyst exhibited higher yields of polycyclic aromatic hydrocarbons and coke during the crude glycerol upgrading process, which could be assigned to its smaller crystal sizes, abundant B acid quantities, uniform and large mesopore diameters. The reusability of desilicated HZSM-5/0.3M NaOH was also deteriorated than the templated HZSM-5/CNT-OH and HZSM-5/TPOAC due to the inferior stability of incorporated mesoporosity via desilication. Finally, plausible reaction pathway involved catalytic upgrading of crude glycerol to produce aromatics was proposed in detail.

Synergistic removal of NO and soot by Fe-W-Zr-ZSM-5 catalysts in a wide temperature window

Obtaining the synergistic catalytic removal of NO and soot is a highlight topic as both NO and soot are the main pollutants from diesel engine. However, synergistic catalytic removal is still very difficult because the temperature window varies with the traditional SCR catalyst of NO at narrow temperature of 300–450 ℃ and the oxidation temperature of soot at high temperature of 500–700 ℃. Therefore, based on W-Zr-ZSM-5 catalyst, a series of M-W-Zr-ZSM-5 (M = Cu, Fe or Nb) catalysts were prepared by sol–gel method to investigate the synergistic catalytic removal of NO and soot, which emitted from diesel engine at the same time. The results showed that Fe-W-Zr-ZSM-5 catalyst exhibited the best NH3-SCR reaction activity and oxidizing performance of soot among the catalysts, with more than 90 % NO conversion in the temperature range of 320 ℃ to 580 ℃ and completely oxidization of soot in the temperature range of 432 ℃ to 543 ℃. The results of XRD, BET, XPS and Raman spectrum indicated that there was strong interaction between W and Fe, promoting the formation of W5+ and W = O species, thereby increasing the content of chemisorbed oxygen, the amount of surface acid sites and redox capacity of the catalysts. Meanwhile, the redox capacity of Fe-W-Zr-ZSM-5 was responsible for the improvement of NH3-SCR activity and the oxidation of soot at low temperature. Fe-W-Zr-ZSM-5 catalyst demonstrated to be a promising material to synergistic remove NO and soot.

Co-Based Catalysts Supported on Ceria with Different Shape Structures for Hydrodeoxygenation of Guaiacol

CeO2 with three different morphologies of nanorods (CeO2-r), particles (CeO2-p), and cubes (CeO2-c) was prepared, and the guaiacol hydrodeoxygenation over their corresponding Co-based catalysts was performed at 160–220 °C, 2 MPa, a H2 flow rate of 80 mL/min, and a weight hourly space velocity of 0.7 h–1. Compared with Co/CeO2-p and Co/CeO2-c, Co/CeO2-r has smaller Co particle sizes, a higher Brunauer–Emmett–Teller surface area, and larger amount of Co active centers, oxygen vacancies, and weak acid sites. These better physicochemical properties for Co/CeO2-r provide more Co active sites for guaiacol hydrodeoxygenation, favor the adsorption and activation of guaiacol, and contribute to the cleavage of C–O. Therefore, Co/CeO2-r presents a maximum guaiacol conversion of 97.1% and the highest yield of cyclohexanol of 91.7% among these catalysts. The result shows that the shape structure of CeO2 has an important influence on the guaiacol hydrodeoxygenation performance over its corresponding catalysts.

Catalytic ozonation with γ-Al2O3 sphere supported highly dispersed iron species: Preparation, performance and catalytic mechanism

Maximizing the number of active sites is important to obtain an excellent catalytic activity for supported metal catalysts. Herein, citric acid-modified Al2O3 spheres in millimeter scale were employed as the porous support for loading iron species by a impregnation-calcination method using Fe(NO3)3‧9 H2O as the metal precursor. A good dispersion of the iron species inside the Al2O3 spheres was achieved, and the characterizations revealed that Fe sites were incorporated into the framework of Al2O3 in the form of -[Al-O-FeIII]- structure. The obtained FeIII/CA-Al2O3 catalyst was found to have a significantly increased amount of surface Lewis acid sites (LAS), showing a better performance than the counterpart catalyst Fe2O3/Al2O3 for p-nitrophenol (PNP) degradation. It was found that the presence of both oxidizable organic pollutants (as electron donator) and ozone was the prerequisite for observing the transformation from surface-ferric (FeIII) to surface-ferrous (FeII) iron on the surface of FeIII/CA-Al2O3 catalyst. In comparison with Fe2O3/Al2O3 catalyst, the FeIII/CA-Al2O3 catalyst also demonstrated a higher level of FeII during the catalytic reaction, suggesting that it had more iron active centers for the catalytic reaction. The cycle of the redox couple FeIII and FeII played an important role for producing the reactive oxygen species. This study confirms that the modification of γ-Al2O3 spheres with citric acid enabled a highly homogeneous dispersion of iron within the support matrix, providing a feasible route for the synthesis of high-performance and low-cost iron-bearing catalysts for industrial application.

Comparison of hydrocracking and cracking of pyrolytic lignin over different Ni-based catalysts for light aromatics production

This work compared hydrocracking and cracking of pyrolytic lignin (PL) for light (single-ring and double-ring) aromatics production over Ni-based catalysts. Due to the supports' original acidities and the interactions between metal and supports, these Ni-based catalysts had different amounts of available Ni and acid sites, which affected depolymerization and deoxygenation in both cracking and hydrocracking. During cracking, the PL depolymerization could be promoted by increasing Ni and acid sites but this promotion was limited by the hydrogen inside PL, whereas both Ni and acid sites exhibited poor performance in deoxygenation. The cooperation of Ni and acid sites achieved efficient hydrodepolymerization and hydrodeoxygenation in hydrocracking. Acid sites benefitted the cracking of linkages in PL and the resulting intermediates could be converted into monophenols through Ni-catalyzed hydrogenation. In the selective hydrodeoxygenation mechanism of monophenols to monoaromatic hydrocarbons, acid sites facilitated the initial tautomerization and the final dehydration reactions, while the middle hydrogenation step was catalyzed by Ni. Additionally the micropore structure of catalyst also favored the generation of light aromatics. Therefore, hydrocracking over Ni/HZSM-5 with sufficient available Ni and acid sites and the micropore structure, realized the most effective conversion of PL to light aromatics, especially aromatic hydrocarbons.

Experimental investigation on biodiesel production through simultaneous esterification and transesterification using mixed rare earth catalysts

In this study, biodiesel production through simultaneous esterification and transesterification of palm oil with 10 wt% of oleic acid using the mixed rare earth catalyst was investigated. The mixed rare earth catalysts were prepared via the co-precipitation method. The effects of the precipitating parameters such as temperature, stirring speed and pH on the physicochemical and morphology of the catalysts were studied. All catalysts were thoroughly characterized using X-ray diffraction (XRD), scanning electron microscopy-energy dispersive spectrometer (SEM-EDS), fourier transform-infrared spectroscopy (FTIR), N2 adsorption/desorption, CO2 temperature programmed desorption (CO2-TPD) and NH3 temperature programmed desorption. (NH3-TPD). The results indicated that the mixed rare earth catalyst prepared under the precipitation conditions: at pH 9, a stirring of 400 rpm and temperature of 30 °C showed the highest catalytic of 90% FAME content. High surface area of the catalyst, a significant larger amount of Ce and La contents in the catalyst and an appropriate amount of acid and basic sites on the catalyst led to the high catalytic activity. The catalyst could also accelerate the initial reaction rate to achieve the high FAME content of 50% within 30 min.

Phosphotungstic Acid-Modified MnOx for Selective Catalytic Reduction of NOx with NH3

H3PW12O40-modified MnOx catalysts (denoted as Mn-HPW) were used for NOx elimination with co-fed NH3. The optimal Mn-HPW0.02 catalyst exhibited over 90% NOx conversion at 90–270 °C. The incorporation of HPW increased the amount of Lewis acid sites of the catalyst for adsorbing NH3, and accelerated the reaction between the adsorbed NH3 species and gas-phase NOx, thus, increasing the low-temperature catalytic activity. The oxidation ability of the Mn catalyst was decreased due to the addition of HPW, thus, mitigating the overoxidation of the adsorbed NH3 species and improving the de-NOx activity and N2 selectivity in the high-temperature region. DRIFT results revealed that the NH3 species on Lewis and Brønsted acid sites, bridged nitrate, and bidentate nitrate were important species/intermediates for the reaction. NH3-SCR over the Mn and Mn-HPW0.02 catalysts obeyed the Eley–Rideal and Langmuir–Hinshelwood mechanisms, simultaneously, at 120 °C.

Production of γ-valerolactone from ethyl levulinate over hydrothermally synthesized Sn-Beta under mild conditions

Production of γ-valerolactone (GVL) from ethyl levulinate (EL) was studied by catalytic transfer hydrogenation (CTH) strategy under mild conditions. Hydrothermally synthesized Sn-Beta zeolites with high crystallinity show high catalytic activity and selectivity. With isopropanol as hydrogen source, 97.1 % GVL yield with 100 % selectivity was given under 110 °C. Crystallization time for synthesis of Sn-Beta showed great effect on the catalytic performance. Sn-Beta-xd catalysts with longer crystallization time (≥7 days) have high crystallinity and better catalytic performance. Firstly, longer crystallization time is necessary for the formation of large amount of Lewis acid sites which catalyze the conversion of EL to GVL. Secondly, high level of silanol groups in Sn-Beta has negative effect on the catalytic performance. High crystallinity means the amount of silanol groups in Sn-Beta-xd at a low level which is favorable for this CTH reaction. Meanwhile, this is why hydrothermally synthesized Sn-Beta shows higher catalytic activity than post-synthesized Sn-Beta in the conversion of EL to GVL. Furthermore, the catalyst was reusable.

Insight into induction period of methanol conversion reaction: Reactivity of ethene-precursors over H-ZSM-5 zeolite is independent of Brϕnsted acid site density

A series of H-ZSM-5 (TZ-m, m represents different Si/Al ratios) has been prepared and their Methanol to Olefin (MTO) performance are investigated. By adjusting the catalyst weight of H-ZSM-5 loaded in the pulse micro-reactor, the total Brϕnsted acid sites (BAS) amount of TZ-m catalysts is unified. The resultant similar methanol conversion (∼24 %) over different TZ-m zeolites confirms that the MTO reaction is dominantly catalyzed by BAS. Nevertheless, the BAS density considerably influences the reaction pathways; more condensed BAS enhances the relative propagation of aromatic-based cycle to alkene-based cycle, and vice versa. However, isotopic co-feeding and switching experiment reveals that the reactivity of aromatic hydrocarbon pool (HCP) species, which has been considered as main ethene precursors, is almost independent of acid site density. Although large amounts of aromatics are generated via hydrogen transfer reactions on the sample with high acid site density, most of the confined aromatics function as coke precursors instead of active HCPs. The accumulation of such confined aromatics in zeolite channels further limits olefins mobility and their access to BAS, leading to decreased reactivity of alkene HCPs on high acid site-density samples.

Sulfate-enhanced low-temperature activity of Pt/γ-Al2O3 for landfill gas deoxygen

Deoxygen is a crucial step for landfill gas (LFG) recycling and purification. Pt/γ-Al2O3 is the most active catalyst for LFG deoxygen via catalytic methane oxidation. It is challenging but significant to further improve the performance of this type of catalyst. In regard of homogeneous and heterogeneous activation of methane by superacids, here we demonstrate LFG deoxygen via catalytic methane oxidation using a solid superacid catalyst, Pt/SO42-/Al2O3, synthesized using pre-sulfated γ-Al2O3 support by impregnated with sulfuric acid. In comparison to Pt/γ-Al2O3, Pt/SO42-/Al2O3 catalysts exhibit exceptionally improved activity and minimum complete O2 conversion at a temperature of 264 ℃, a decrease of about 51 ℃. This value is superior to the state-of-the-art Pt-based deoxygen catalysts. Characterizations and theoretical calculations indicate that sulfation enhances the amount of acid sites on γ-Al2O3 support and induces electron deficiency of the supported Pt species (+0.28|e|), thus boosting the low-temperature activity. Furthermore, the Pt/SO42-/Al2O3 catalyst maintained its initial activity after six runs without any detectable coke deposition. This discovery offers simple and effective strategies to precisely design higher performance application-oriented Pt based deoxygen catalysts.

Effect of ZnO morphology on the performance of CuZnAl slurry catalysts for the ethanol synthesis from syngas

The impact of nanomaterial morphology on the structures of catalysts has drawn intense interest. Based on previous work, we discovered that ZnO plays an essential role in the ethanol production. In this research, we discussed the impact of ZnO with different morphology (rod-like, granular-like and flower-like) on the performance of CuZnAl slurry catalysts for the ethanol production. The catalytic performance was evaluated at H2/CO = 2, 250 °C and 4.0 MPa, and the catalyst structures were tested by XPS, in situ DRIFT and so on. The results show that CuZnAl catalysts prepared with rod-like and granular-like ZnO show the better selectivity of methanol and DME, which is assigned to the highly dispersion of Cu species and more quantity of acidic sites, respectively. CuZnAl catalyst prepared with flower-like ZnO possesses the higher total alcohol selectivity (45.0%) and the highest ethanol proportions in total alcohol (50.0%). Flower-like ZnO that exposed more polar (002) facets results in more surface defect structures (oxygen vacancy, Zn(2-δ)) and high ratio of Cu0/Cu+ in this catalyst, all of which are related to the formation of ethanol.

ADSORPTION STUDY OF ACETONE ON THE SORBENTS BASED ON MONTMORILLONITE

Corresponding cation forms of the montmorillonite samples taken from the Ag-Dere bentonite deposit were obtained by processing them with Co2+ and Ni2+ salts. The nature and amount of acid sites formed on the surfaces of the obtained samples were studied by adsorption of acetone using the derivatographic method. The critical diameter of the acetone molecule is d = 5.6A0 and pkα = -7.2. Analysis of derivatograms shows that the mass loss changes depending on the ionic radius, nature and temperature of the cation exchanges as follows: Co2+ mont> Ni2+ mont> natural mont. Based on the conducted study it was estableshed that there are weak, medium and strong electron-acceptor centers on the surface of the sorbent which differ energetically. The endothermic effect observed on the DTA curve at a temperature range of 219.3–566.30C characterizes the physical adsorption of an acetone molecule on the surface of a montmorillonite sample. The effects observed at 706.9 and 775.70C characterize the strong acid sites. The amount of electron-acceptor centers formed on the surface of monmorillonite changes depending on the charge of cation exchangers. The number of electron-acceptor centers formed on the surface of Co2+ bentonite is higher than in other samples. The amount (a.mmol.g) and desorption energy (E, kDc, mol-1) of acetone molecule desorbed from the active sites in different temperature ranges were calculated. It was determined that the most capable of adsorbing acetone molecules is Co2+-montimorillonite, which can be used as a sorbent to prevent envoiremental pollution with acetone. Corresponding cation forms of the montmorillonite samples taken from the Ag-Dere bentonite deposit were prepared by processing with Co2+ and Ni2+ salts. The nature and amount of acid sites formed on the surfaces of the obtained samples were studied by adsorption of acetone using the derivatographic method. Based on the conducted study it was estableshed that there are weak, medium, strong electron-acceptor centers on the surface of the sorbent which differ energetically. The amount (a.mmol.\g) and desorption energy (E, kDc, mol-1) of acetone molecule desorbed from the active sites in different temperature ranges were calculated. As a result of the research, it was found that the most capable of adsorbing acetone molecules is Co2+-form of montimorillonite, which can be used as a sorbent to prevent envoiremental pollution with acetone

Doping effect of rare earth metal ions Sm3+, Nd3+ and Ce4+ on denitration performance of MnOx catalyst in low temperature NH3-SCR reaction

The MnXOx catalysts (i.e., MnSmOx, MnNdOx, MnCeOx) were prepared by reverse co-precipitation method and used for NH3-SCR reaction. It is found that MnCeOx catalyst presents the best low temperature catalytic activity (higher than 90% NOx conversion in the temperature range from 125 to 225 °C) and excellent H2O + SO2 resistance. In order to explore the reason for this result, the characterization of X-ray diffraction (XRD), Raman spectroscopy, Brunauer–Emmett–Teller (BET), H2-temperature programmed reduction (H2-TPR), NH3-temperature programmed desorption (NH3-TPD), X-ray photoelectron spectroscopy (XPS) and in situ diffuse reflaxions infrared Fourier transformations spectroscopy (DRIFTS) were conducted. The obtained results suggest that MnCeOx catalyst shows the largest amount of acid sites and the best reducibility among these MnXOx catalysts. Besides, Ce4+ doping inhibits the crystallization of MnOx catalyst and shows the largest specific surface area. Finally, in situ DRIFTS experiments reveal that NH3-SCR reaction over MnCeOx catalyst follows both Langmuir–Hinshelwood (L-H) and Eley-Rideal (E-R) mechanisms, which is through “fast SCR” reaction.

Etherification of hydroxymethylfurfural with ethanol on mesoporous silica catalysts of regulated acidity to obtain ethoxymethylfurfural, a bio-additive for diesel

5-(hydroxymethyl)furfural (HMF) obtained from biomass can be etherified with ethanol to 5-(ethoxymethyl)furfural (EMF), a promissory bio-additive for diesel, employing solids with suitable acidity and porous structure as catalysts. The performance of MCM-41 and SBA-15, with different amount of sulfonic acid sites (-SO3H), was compared at 140 °C in a batch stirred reactor. 10 g L−1 of SBA-15 with a 0.054 S/Si molar ratio gave HMF conversion of 94.6% and EMF yield of 76.5% after 3 h of reaction from a 15 g L−1 of HMF/ethanol. The catalyst preserved its activity over 4 reaction cycles; reaching HMF conversion of 78.0% and EMF yield of 68.7%. From 90 g L−1 of HMF/ethanol and 20 g L−1 of catalyst achieve a HMF conversion of 94.3% and an EMF yield of 89.3% in 1.5 h of reaction (rate of 69.1 g L−1 h−1). A scale-up of production to a continuous reactor could be considered.

Binder‐free Zeolite Beta Beads with Hierarchical Porosity: Synthesis and Application as Heterogeneous Catalysts for Anisole Acylation

AbstractThree zeolites (H‐Beta, H‐ZSM‐5 and H‐Y) were synthesized in the form of binder‐free macroscopic beads (d=215–840 μm) using a hydrothermal method employing anion‐exchange resin beads as hard template. The beads obtained after removal of the hard template by calcination consisted of crystalline zeolite domains connected with each other to form a hierarchical porous network in which the zeolitic micropores are accessible through meso‐ and macropores, as proven by characterization with XRD, N2 physisorption, SEM, and TEM. The composition, the nature and amount of acid sites and the degree of hydrophobicity of these beads were investigated by means of XRF, solid‐state NMR, pyridine‐FTIR and TGA. The zeolite beads were tested as heterogeneous catalysts in the Friedel‐Crafts acylation of anisole with acetic anhydride to produce para‐methoxyacetophenone. H‐Beta‐Beads displayed the best catalytic performance with 95 % conversion of acetic anhydride and 76 % yield of para‐methoxyacetophenone in a batch reactor test (90 °C, 6 h). Next, the catalytic performance of H‐Beta‐Beads was compared in both batch and continuous‐flow mode to extrudates prepared by mixing zeolite Beta powder with either kaolin or bentonite binders. H‐Beta‐Beads outperformed the extrudates in batch‐mode reactions and could be reused in multiple runs without discernible loss of activity. In the continuous‐flow test, H‐Beta‐Beads demonstrated higher average activity but deactivated more rapidly than the extrudates.

Acid-Modified Clays for the Catalytic Obtention of 5-Hydroxymethylfurfural from Glucose

5-hydroxymethylfurfural (5-HMF) is an important platform molecule for the synthesis of high-added value products. Several synthesized clay materials, such as mesoporous hectorite and fluorohectorite, in addition to commercial montmorillonite K-10, have been acid modified by different methodologies to be applied as catalysts for the obtention of 5-HMF from glucose. The effects of the Brønsted and/or Lewis acidity, the reaction temperature and time, and the catalyst/glucose ratio on the conversion but especially on the selectivity to 5-HMF have been studied. By comparing the synthesized clays, the best selectivity to 5-HMF (36%) was obtained at 140 °C for 4 h with H-fluorohectorite because of the presence of strong Brønsted acid sites, although its conversion was the lowest (33%) due to its low amounts of Lewis acid sites. Different strategies, such as physical mixtures of montmorillonite K10, which contains high amounts of Lewis acid centers, with Amberlyst-15, which has high amounts of Brønsted acid sites, or the incorporation of rhenium compounds, were carried out. The best selectivity to 5-HMF (62%) was achieved with a mixture of 44 wt % Amberlyst-15 and 56 wt % of montmorillonite K10 for a 56% of conversion at 140 °C for 4 h. This proportion optimized the amount of Brønsted and Lewis acid sites in the catalyst under these reaction conditions.

Catalytic fast pyrolysis of cellulose over different metal-modified ZSM-5 zeolites for light olefins

Light olefins (C2H4, C3H6 and C4H8) are important chemical building blocks in modern energy and material system. In this study, the effects of different metal-modified ZSM-5 catalysts on the production of light olefins from cellulose fast pyrolysis were investigated in a fixed bed. Fe, La, Cu, Mg, Al and Ce modified ZSM-5 were prepared by the impregnation method, and then the derived modified ZSM-5 catalysts were characterized by different analytical instruments. The correlation between catalyst characteristics and the production of light olefins was explored. The results showed that the specific MFI-type structure of ZSM-5 remained intact after modification, and the surface area, pore volume and the amount of acid sites of catalysts varied. The highest light olefins yield was obtained over Cu-ZSM-5 (7.64 C-mol%), while the lowest was achieved over Mg-ZSM-5 (3.75 C-mol%). Moreover, the formation of light olefins can be promoted with the increasing of ZSM-5 other-pore volume and surface area, medium and strong acidity, and the decreasing of micro-pore volume and surface area, weak acidity. The results may share some light on the design of high efficiency ZSM-5 catalyst for high light olefins production.

Promotion of boron phosphate on the NiMoAl catalyst for hydroprocessing FCC slurry oil

Mesoporous NiMoAl catalysts with boron phosphate (BPO4) modification were synthesized through the complete liquid-phase method. X-ray diffraction (XRD) analysis evidenced the presence of BPO4-AlOOH mixed support in these BPO4-modified NiMoAl samples. The total amount of acid sites declined, but the surface acidity was strengthened by adding BPO4 into the NiMoAl catalyst. It's worth noting that the incorporation of BPO4 could increase the concentrations of Ni and Mo species on the catalyst surface and greatly improve the dispersion of (Ni)MoS2 active phases, as indicated by X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) measurements. The catalytic performance of these BPO4-modified NiMoAl catalysts was investigated with the hydroprocessing of fluid catalytic cracking (FCC) slurry oil. The nitrogen-containing compounds removal from the oil was significantly enhanced with increasing the molar ratio of boron phosphate/aluminum. The NM-BPA(0.55) catalyst exhibited the best hydrodenitrogenation (HDN) activity, highlighting the significant impact of Mo sulfidation degree and the dispersion of active metals on HDN performance. The introduction of boron phosphate could also promote the hydrocracking activity of the NiMoAl catalyst, as demonstrated by SARA analysis and simulated distillation of liquid products.

Al-free Zr-beta zeolite as a selective catalyst for the ketalization of glycerol

Two Zr-beta zeolites were synthesized using different methods. Method 1 consisted in the formation of a dealuminated zeolite beta seed followed by Zr incorporation and thermal treatment (ZBZr1). In Method 2, zeolite beta was prepared and then, the dealumination and subsequent Zr incorporation were performed (ZBZr2). These materials were tested in the ketalization of glycerol with acetone and compared with a SBAsulf. Both preparation methods incorporate Zr in the zeolitic framework, and no ZrO2 is detected. Method 1 developed crystallites with an average size of 260 nm, Si/Zr ratio ∼100, total amount of acid sites of 0.375 mmol.g−1 and a ratio of Brönsted to Lewis acid sites of 1.9. In the case of Method 2, values of 1500 nm, ∼86, 0.32 mmol.g−1 and 0.7 were obtained, respectively. The ZBZr2 sample presented low catalytic activity, possibly due to diffusion limitations. The turnover frequency (TOF) was calculated as 44.84 and 60.37 min−1 for ZBZr1 and SBAsulf , respectively. After one cycle of reaction, both ZBZr1 and SBAsulf showed a decrease in the glycerol conversion, however, the selectivity remained constant in the ZBZr1 material after the reaction cycle and the catalytic activity could be reestablished after a thermal treatment.