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In this study, we investigated the application of an acidic titanium dioxide catalyst in fixed bed reactors for the isomerization of α-pinenes.

Summary of the synthesis, structures and catalytic applications of Zr- and Ti-based MOFs.

The service life of HY zeolite is 480 h under industrial conditions, and it can be regenerated by roasting.

Al-Incorporated sulfated zirconia with improved and stabilized surface sulfur species was synthesized via the co-precipitation method and used as an effective catalyst to remove trace olefins from aromatics in a fixed-bed reactor. The textural and chemical properties of various catalysts were characterized by XRD, 27Al MAS NMR, N2 adsorption, EA, XPS, H2-TPR, FT-IR, and pyridine-infrared (IR) spectroscopy techniques to elucidate the Al promoting effect on acid centres and catalytic performance. The results demonstrated that incorporating Al into zirconia could effectively stabilize the tetragonal zirconia with small grain size and improve surface sulfur species, thereby balancing the distribution of Bronsted and Lewis acid sites. Consequently, sulfated zirconia incorporating Al at the level of Al/Zr < 7.5 mol% exhibited more outstanding catalytic activity and stability under a long reaction time compared with conventional sulfated zirconia. Notably, superior reusability with a negligible drop in olefins conversion over five reaction cycles was obtained in the presence of the Al2.50-SZ. The alkylation reaction process of olefins with aromatics was further investigated by the GC-MS technique when Alx-SZ was used as the catalyst.

Double perovskites (DPs) are one of the most promising candidates for developing white light-emitting diodes (WLEDs) owing to their intrinsic broadband emission from self-trapped excitons (STEs). Translation of three-dimensional (3D) DPs to one-dimensional (1D) analogues, which could break the octahedral tolerance factor limit, is so far remaining unexplored. Herein, by employing a fluorinated organic cation, we report a series of highly luminescent 1D DP-inspired materials, (DFPD)

HY zeolite is commonly considered to have a suitable pore structure for alkylation of aromatic. However, coke deposition results in catalytic activity falling rapidly because of its strong acidity. Herein, we prepared WO3/HY zeolite catalysts by liquid phase deposition method with phosphotungstic acid as the precursor, and their catalytic activities were evaluated by alkylation of naphthalene and n-tetradecene (C14H28). Characterizations showed that WO3 increased acid density and optimized the distribution of surface acidity and pore structure. The process not only increases the W5+ content which can increase the catalytic activity, but also reduces the reaction temperature to extend the service life. Both advantages of the catalysts achieved 96.12% conversion of naphthalene and 97.46% selectivity of monoalkylnaphthalene.

β Zeolite/bentonite composite was synthesized by simple kneading as catalyst for condensation reaction of aniline to diphenylamine. The experiment which was conducted at 320 °C under 2 MPa with a liquid hourly space velocity (LHSV) of 2 h−1 showed that the Hβ zeolite loading 25% clay exhibited the highest activity (9.9% aniline conversion) and selectivity. Pilot experiments (315–320 °C, 2 MPa, LHSV of 0.20–0.22 h−1) have also confirmed that the catalyst had good stability. The crystalline structure, acidic property and textural property of the catalysts were characterized by XRD, Py-IR, N2 adsorption–desorption. Moreover, according to the thermodynamic analysis, the condensation of aniline to diphenylamine is an exothermic reaction, indicating that too high temperature operation is unfavorable for the reaction. The studied β zeolite/bentonite composite is of promising efficiency in condensation of aniline to diphenylamine.

The hydrogenation catalyst plays an important role in removing trace olefins from aromatics. In this work, a Cu/ZnO/montmorillonite catalyst was developed. The Cu/ZnO/montmorillonite catalyst is not only comparable in performance to the noble metal Pt/montmorillonite catalyst, but also has greater potential because the activity of the catalyst at low hydrogen flow is almost the same as that at high hydrogen flow. Moreover, aromatic cracking will not occur under the action of the Cu/ZnO/montmorillonite catalyst. The activity of the modified catalyst used to remove olefins is stable at about 92% at low weight hourly space velocity (WHSV). The three functions of ZnO are summarized as follows: (i) Zinc oxide is beneficial to restore the BET surface area of the Cu-based catalyst. (ii) Zinc oxide can improve the amount of Cu that can be reduced by hydrogen. (iii) ZnO increases the grain size of Cu2(NO3)(OH)3, resulting in a higher reduction temperature for Cu-based catalysts.

By hetero atom doping, a nitrogen-doped porous carbon was synthesized and applied to catalytic oxidation removal of NO. The synthesis conditions and NO removal process conditions of the modified carbon material were investigated, including calcination temperatures, impregnation amount, NO inlet concentration (100–500 ppm) and catalytic reaction temperature. The results showed that the dicyandiamide impregnation solution concentration of 0.5 M, and the calcination temperature of 600 °C performed the best in the preparation of structurally stable nitrogen-modified carbon. Due to the formation of a large number active centers of pyridine nitrogen (N-6) groups and graphitic nitrogen (N-Q) groups, the optimal conversion rate of NO could reach 67.2%.

H-ZSM-5, H-IM-5, and H-IM-5(DS) zeolites were synthesized as highly active and shape selective catalysts for the alkylation of benzene with methanol. The samples were characterized by N2-adsorption-desorption, XRD, SEM, TEM, NH3-TPD, and Py-FTIR. The benzene conversion and xylene selectivity were in the same order H-IM-5(DS) > H-IM-5 > H-ZSM-5, while the toluene selectivity was in the reverse order. Combined with the analysis of pore structure and TEM, H-IM-5(DS) zeolite was equipped with more meso/macropores and it exhibited even better catalytic properties. The optimum reaction condition with H-IM-5(DS) as catalysts was obtained.

A phosphorus modified HZSM-5 sample with excellent p-xylene selectivity was successfully obtained by a method of reversing the external surface ZSM-5 crystals to positive charged by HDTMA, which could selectively deposit the phosphorus on the external surface and pore entrance. The texture properties were characterized by XRD, XRF and N2 adsorption–desorption. The accessibility of acid sites was determined by NH3-TPD and Py/Coll-IR. The solid-state NMR measurement indicated that more phosphorus did not enter the pores of the MZS-1.5P sample and existed as H4P2O7 or polyphosphates not connected to aluminum. Applied to alkylation of toluene with methanol, MZS-1.5P sample all exhibited excellent para-selectivity at reaction temperatures of 360–420 °C and WHSV of 1.0–4.0 h–1. The TPD of xylene analysis showed that the interactions between diffusing molecule and surface of ZSM-5 as well as the geometric factors play important roles in the diffusion process.

A heterogeneous Cu modified Y zeolite is prepared for acetylene carbonylation, and acrylic acid yield is up to 86%; this catalyst could maintain ∼50% of initial activity even after three catalytic cycles. Regenerating the spent catalyst in air followed by N2 could restore the activity to 80%. Multiple measurement techniques, including XRD, ICP, XPS, NH3-TPD, TGA, Raman and SEM are carried out to obtain a deep understanding of the catalyst deactivation. During the reaction process, unreacted acetylene is pyrolyzed, solubilized, diffused, accumulated and solidified as disordered carbonaceous particles on the catalyst, then transferred to ordered filaments. At the same time, CuO is dissolved into the reaction liquid and only Cu+ is left, which reduce the acidity of catalyst in both amount and strength. Results show that factors causing the catalyst deactivation obey the following order: coke deposition > copper loss > acidity weakening > crystallinity collapse.

In this work, sulfated zirconia (SZ) was prepared by a solvent-free method, ammonium sulfate ((NH4)2SO4) and sulfamic acid (NH2SO3H) were as sulfur sources, respectively. The resulting catalysts were characterized by powder X-ray diffraction (XRD), thermogravimetric analysis and differential scanning calorimetry (TGA-DSC), N2 adsorption–desorption isotherms, inductively coupled plasma (ICP) and pyridine-FTIR. The characterization of the catalysts revealed that SZ prepared with (NH4)2SO4 as sulfur source contained more Lewis acid sites and less Brønsted acid sites. The effects of sulfur sources on the catalytic activity of catalysts were studied. Catalytic testing showed that SZ prepared with (NH4)2SO4 as sulfur source had a better catalytic performance for removing trace olefins from aromatics. Keywords: Aromatics, Olefins, Sulfur sources, Sulfated zirconia

Metallic oxides were introduced into the synthesis of sulfated zirconia. Catalytic activity was tested by an olefin removal reaction. By combining the analysis from the aspect of catalyst morphology, sulfur state and surface acid property, we concluded that the incorporation of metallic oxides has three important positive effects on the environmental friendly solvent-free preparation: (i) it inhibited the phase transition during calcination and promoted the existence of tetragonal ZrO2, which is recognized as the valid phase; (ii) it increased the amount of S, especially S6+, which is the source of active sites; and (iii) it adjusted the surface acid property, extended the single service lifetime and reduced the deactivation rate.

Herein, a core–shell H-IM-5@meso-SiO2 hybrid material was synthesized by reversing the charge of the external surface of IM-5 crystals to a positive charge by PDDA that could induce an oriented self-assembly formation of the meso-SiO2 shell. The as-synthesized H-IM-5@meso-SiO2 composite was thereafter modified with phosphorus species to further enhance the selectivity of the target product. The sample morphology and structure were analyzed by electron microscopy technology, XRD, XPS and N2 adsorption–desorption. The effects of the meso-SiO2 shell and phosphorus species on sample acidity were investigated by NH3-TPD, FTIR spectroscopy and solid-state NMR measurements. The catalytic properties and characterization results revealed that the meso-SiO2 shell could passivate the external surface acids of the H-IM-5 crystals. The phosphorus modification could simultaneously adjust the surface acidity as well as the size of the pores and pore-openings. The TPD analysis of xylene showed that the sample surface acidity and geometric factors played important roles in the diffusion process of the diffusing molecules.

A series of zirconium hydroxide and sulfated zirconia were prepared by a facile hydrothermal method without a template. The catalysts were characterized by XRD, BET, SEM, TEM, TG-DSC, Raman, NH3 TP...

In this research, ultrafine CeO2 nanoparticles modified porous carbon spheres were developed from waste resins and their efficiency in removing Cr(VI) from aqueous solutions was tested, which exhibited excellent adsorptive activities. Furthermore, various characterization methods were employed to prove that the CeO2 nanoparticles and raw carbons were closely bonded with one-step impregnation. Results showed that carbon spheres decorated with ultrafine CeO2 nanoparticles improves the removal efficiency by nearly six times compared with the raw carbons, reaching 90% for 100 mg/L Cr(VI). The kinetics and adsorption isotherm tests confirmed that the process was pseudo-second-order and controlled by both external transfer and intra-particle diffusion. Regeneration experiments verified long stability of the adsorbents, suggesting KSAC-CeO2 is a type of promising absorbent for the Cr(VI) removal from wastewater.

A palladium-nickel doped sulfated zirconia was prepared, and hydrogen spillover and bimetallic synergic effect were confirmed using this model catalyst. Isomerization of n-hexane indicated that palladium and nickel could enhance both the conversion rates and selectivity. The XRD and BET results showed that nickel had a strongly influence on the crystal form and catalyst structure. TG-DSC analysis showed the loaded nickel could decrease the sulfates concentrations. Therefore, the total acidity, especially the strong Bronsted acid sites decreased in the presence of nickel, as analyzed by pyridine IR spectroscopy. H2 TPR analysis indicated both the nickel and palladium could improve the reducibility of sulfated zirconia. And combined with XPS results, the nickel oxide was found easier to reduce in the presence of palladium, and higher reduction temperature could lead to the formation of NiAl2O4. Finally, the mechanisms of hydrogen spillover and reaction process were deduced.

In this research, low-cost activated carbons (ACs) derived from deactivated resin catalyst (DRC) for methyl tert -butyl ether synthesis were successfully prepared through carbonization and subsequent steam activation or KOH activation. Differences in physical and chemical properties of ACs and their performance on dibenzothiophene (DBT) adsorption from model fuel were investigated systematically. AC prepared by KOH activation (KSAC) has abundant micropores, whereas mesopores are the major part of AC prepared by steam activation (HSAC). Both KSAC and HSAC have few acidic groups, in accordance with their oxygen content. DBT adsorption performance is dependent largely on physical properties. The maximum adsorption capacity (16.1 mgS/g at 100 ppmS) and the longest breakthrough time (16 h, 10 h −1 WHSV) were observed for KSAC.

Sulfated zirconia was synthesized by a one step solvent-free method, directly mixing Zr(OH)4 and (NH4)2SO4. The entire synthesis process produces no wastewater, which is environmentally friendly. The synthesis factor (mole ratio of (NH4)2SO4:Zr(OH)4) is the main point to test catalytic activity. Structural properties are characterized by X-ray diffraction (XRD), N2 adsorption–desorption isotherms, and inductively coupled plasma (ICP). The acid property is characterized by pyridine-FTIR. The S coverage (×10–6 mol S·m–2)–Lewis acidic sites density (mmol·m–2) relationship in sulfated zirconia reveals that the generation order of Lewis acidic sites is from weak ones to strong ones. Calculation of acid property reveals the positive structural–functional relationship (WL/SL–catalytic activity). Weak Lewis acidic sites (WL) promote the activity toward removal olefins, while strong Lewis acidic sites (SL) speed up the deactivation of catalysts. The superior catalytic performance as well as environmentally friendl...

A high-aluminum-content sulfated zirconia was prepared by the kneading method, and the washing process was considered as a key factor. Catalysts were characterized by XRD, BET analysis, SEM, TG, FT-IR spectroscopy, pyridine IR spectroscopy, NH3 TPD, H2 TPR, and 27Al NMR spectroscopy, and the reactivity was evaluated by n-hexane isomerization. The results showed that the high-aluminum-content sulfated zirconia has a high activity after being washed with water. Moreover, the aluminum content was found to strongly influence the crystal form, catalyst structure, and acidity, as well as the anchoring effect on the labile sulfates. Actually, the higher the aluminum content was, the more sulfates were left in the catalyst samples after washing. The O—H and S═O stretching vibrations were shifted in the presence of aluminum or water. With the support of the aluminum coordination state, a hydrolysis model was deduced for different aluminum contents in the catalysts, and it can explain the formation of more Bronsted...

Catalytic reactions of acetylene have become a subject of renewed interest. However, recent literatures about the synthesis of acrylic acid by acetylene carbonylation were rare to be found. In our research, the yield of acrylic acid is greatly improved to ∼86% (242.85 g Acrylic acid/g Cat.·h) by using heterogeneous catalyst Cu(I)Y, against ∼70% from other reports using complex homogeneous catalyst. Y modified with different valence states copper were prepared by heating the precursor at various atmospheres and characterized by XRD, BET, XPS and FT-IR. More than one type of copper (Cu2+, CuO, Cu2O, Cu+ or Cu0) was found on one sample. Moreover, the distribution and the forming process of these types of copper were determined. According to FT-IR using pyridine or CO as probe, Cu+ at site II′ not only enhanced the acid strength obviously, but also promoted the formation of the most stable monocarbonyls. Furthermore, the strong acid site and the stable monocarbonyls are beneficial for the acetylene carbonylation.

A series of modified HZSM-5 zeolites with different types of acid and different HCl concentrations treatments were synthesized, respectively. The crystal morphology, textural property and acidic property of the catalysts were characterized by XRD, N2 adsorption–desorption, NH3‐TPD, Py-IR and 27Al MAS NMR spectroscopy. The influences of acid treated types and acid solution concentrations in the pore structure, acidity and non-hydrocracking activity were investigated. The results showed that mesopores were successfully induced to HZSM‐5 zeolites after dealumination by HCl and H3PO4 treatment and the acid sites were redistributed. The acidic analysis revealed that the increase of LAS/BAS value was conducive to improving the non-hydrocracking cracking activity and gasoline yield of the samples. It was also observed that an appropriate amount of HCl treatment can not only play the role of dredge the channel of the zeolites, also introduce some new mesoporous. The hydrochloric acid treated sample (HZ-1.0HA) showed the best diesel non-hydrocracking cracking activity and gasoline yield.

Heterogenization of homogeneous catalyst for acetylene carbonylation was carried out by preparing a series of Ni-modified catalysts (Ni-ZSM-5, Ni-IM-5 and Ni-MCM-41). Several important properties of the heterogeneous catalysts were determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES), XPS, XRD, N2 adsorption, pyridine-FTIR, SEM and TGA. Moreover, we used various activity criteria to dissipate perturbing factors, when we focused on the influence of surface structure and active site distribution. The result that Ni-IM-5 had the greatest TOFNi = 5107 g acrylic acid per g Ni per h showed that the surface structure of samples did not influence the catalyst performance significantly. In addition, the highest ratio of nickel sites/acid sites in Ni-MCM-41 represented the best active site distribution. Thus, Ni-MCM-41 has the highest TOFcat = 70.6 g acrylic acid per g cat. per h. Furthermore, stability testing of the catalysts showed the Ni-MCM-41 could be used four times, while others only twice.

Nano-NiO and Bi 2 O 3 modified NiO have been successfully prepared by precipitation method and used as catalyst for the carbonylation of acetylene to acrylic acid. The specimens were characterized by powder X-ray diffraction, N 2 adsorption–desorption, scanning electron microscopy, hydrogen temperature-program reduction and X-ray photoelectron spectroscopy. These results indicated that the introduction of Bi 2 O 3 to the catalyst greatly affected the physical and chemical properties of NiO. The catalytic performance of Bi 2 O 3 /NiO depends on the content of Bi 2 O 3 , and a composite oxide catalyst with 11.1 wt.% of Bi 2 O 3 showed significantly higher activity compared to its components in the pure phase.

Fluidized catalytic cracking (FCC) is an important link in heavy oil processing. Industrial FCC catalyst which mainly consists of molecular sieves, substrates and adhesives is used in large quantities every year. Spent FCC catalyst is one kind of hazardous solid waste that is hard to handle. In this paper, we used a spent FCC catalyst as a desulfurization adsorbent, and show that it displays advanced desulfurization property. Furthermore, regeneration experiment showed that calcination was an effective method to remove the sulfides adsorbed in spent FCC catalyst, after four cycles it still owned a high sulfur adsorption ability. The results of metal impregnation indicated that the high ability to remove sulfur in LPG was due to those metals deposited on WC. The sulfur removal further increased by calcination of the spent catalyst since carbon deposition on the catalyst surface which blocked the active sites was minimized by calcination, thus leading an increase in the number of active sites available.

A non-petroleum route to produce acrylic acid was investigated through hydrocarboxylation of acetylene with CO and water in the presence of Ni2O3 and cupric bromide as combined catalysts. The activity of Ni2O3 was compared with various homogeneous catalysts; the effect of initial total pressure, reaction temperature, molar ratio of CO/C2H2, the volume ratio of solvent/water, the catalyst amount and the role of promoters have been studied in detail. It was found that the acrylic acid space-time-yield as high as 764.6 mol AA/(mol Ni h) was obtained under the optimal experimental conditions. The Ni2O3 catalyst could be reused at least five times without obvious loss of activity. The characterization of recovered catalysts by XRD, XPS, SEM and TG–DTG revealed that the state of nickel remains unchanged during the reaction, and there are three types of soft coke deposited on the surface of the catalyst. The catalysts can be regenerated through calcination within 400 °C according to TG curve.

A series of Ni-modified Y-zeolites with varying Ni loading in the presence of cupric salt as promoter were studied for acetylene hydrocarboxylation performed in a batch reactor. The catalysts were characterized by elemental analysis, H 2 -TPR, XRD, NH 3 -TPD, pyridine-FTIR, SEM, TG-DTG and Raman. It was found that the catalytic activity showed a pronounced dependence on the supports, metal introduction method, promoters and reaction conditions. The nickel species present as charge compensation cations in the zeolite framework constitute the active sites, and the acid sites help to promote the performance of carbonylation. Moreover, two types of coke were observed, and the remarkable reusability of NiY is attributable to the location of the coke outside the zeolite crystals. High catalytic performance was obtained over a NiY(7.0) catalyst with 62 g acrylic acid /(g cat. · h) of yield at 235 °C, 3.6 MPa of initial total pressure and 0.8 mM/l of cupric bromide within 40 min of reaction time. This is the most effective heterogeneous system for synthesizing acrylic acid by carbonylation of acetylene to date.

A series of the imidazolium-based phosphoric ionic liquids, N-methyl-N-methylimidazolium dimethyl phosphate ([Mmim]DMP), N-ethyl-N-methylimidazolium diethyl phosphate ([Emim]DEP), and N-butyl-N-methylimidazolium dibutyl phosphate ([Bmim]DBP), were synthesized and employed in the extraction and catalytic oxidation desulfurization system (ECODS) for the removal of 4,6-dimethyldienzothiophene (4,6-DMDBT) from a model oil, with hexaammonium heptamolybdate tetrahydrate ((NH4)6Mo7O24·4H2O) as catalyst and 30 wt % hydrogen peroxide (H2O2) solution as oxidant. The effects of the type of ionic liquid, amount of catalyst and H2O2, ILs/oil mass ratio, reaction time, reaction temperature, and regeneration of ionic liquid on the 4,6-DMDBT removal of a model oil were investigated in detail. The results indicate that a sulfur system containing H2O2, (NH4)6Mo7O24·4H2O, and [Bmim]DBP, exhibited such a high catalytic activity that the removal of 4,6-DMDBT could reach 89.2% at 50 °C in 3 h, which was markedly superior to me...

Methanesulfonic acid (MSA) was used as catalyst to remove trace organic sulfur (thiophene) from Fluid Catalytic Cracking gasoline (FCC) via alkylation with olefins. The reactions were conducted in Erlenmeyer flask equipped with a water-bath under atmospheric pressure. The influence of the temperature, the reaction time, and the mass ration of MSA were investigated. After a 60 min reaction time at 343 K, the thiophene conversion of 98.7% was obtained with a mass ration of MSA to oil of 10%. The catalyst was reused without a reactivation treatment, and the thiophene conversion reached 92.9% at the third time. The method represents an environmentally benign route to desulfur, because MSA could easily be separated from the reaction mixture via decantation and it could be reused.

Methanesulfonic acid (MSA) was used as the catalyst to remove trace olefins from aromatics (referred to as oil). The reactions were conducted in a round-bottom flask equipped with a reflux condenser and oil-bath under atmospheric pressure. The influences of the reaction temperature, the mass ratio of MSA to oil, and the reaction time were investigated. The experimental results showed that after a 40 min reaction time at 413 K, the olefins conversion of 89.45% was obtained with a mass ratio of MSA to oil of 6%. The catalyst was reused five times without a reactivation treatment, and the olefins conversion reached 66.02% the fifth time. More importantly, the catalytic mechanism was also proposed in this work. In addition, as MSA is biodegradable, this method represents an environmentally benign route to remove trace olefins from aromatics.

Attrition resistance is a key design parameter for catalysts used in slurry phase Fischer–Tropsch (F–T) reactors, especially for industrial-scale reaction. It is well-known that iron F–T catalyst particles undergo physical attrition and chemical stresses caused by phase transformations. Here we report on attrition properties of a Fe–Cu–K–SiO2 catalyst used in a pilot-scale stirred tank slurry reactor (STSR) under low temperature F–T reaction conditions. The wax-free catalysts were characterized by SEM, EDS, BET surface area measurements, and a Mastersizer 2000 for particle size analysis. The results show that, after 408 h of reaction in an STSR, the particle size reduction due to erosion/abrasion and fracture was apparent. Large reductions in the Sauter mean diameter (93.45%) and the volume moment diameter (71.67%) were observed. The increase in the fractions of particles smaller than 5 and 10 μm was 18.25 and 30.11%, respectively. We concluded therefore that the catalyst underwent more severe attrition i...