HY Zeolite Research Articles

High-efficiency hydrocracking of phenanthrene into BTX aromatics over a Ni-modified lamellar-crystal HY zeolite.

A new Ni-HY zeolite with lamellar-crystals was prepared as a catalyst for phenanthrene hydrocracking. It showed significantly improved reactivity and BTX (benzene, toluene and xylene) selectivity (up to 99.1% and 75.6%, respectively), depending on a reasonable synergistic effect between its excellent internal-diffusion and the high-efficiency concerted catalysis of surface metal-Ni active sites and acid sites. In particular, compared with a conventional Ni-HY with diamond-shaped crystals, its significantly shortened diffusion-reaction path of the micropore system in the lamellar crystals greatly enhanced the diffusion-reaction efficiency of large-molecule phenanthrene and polycyclic intermediates and remarkably improved the utilization of both pores and internal reactive sites, powerfully promoting phenanthrene into benzene series conversion. The much decreased diffusion-residence time of benzene-series products in shortened channels also effectively weakened the further cracking loss of the benzene-ring, leading to enhanced BTX selectivity. Moreover, this shorter-channel Ni-HY catalyst with a higher external surface area and mesoporous volume also exhibited greatly improved catalytic stability attributed to its stronger capabilities of accommodating coke and resisting coke-deposition. The phenanthrene conversion of >76.3% and the BTX yield of >46.3% were obtained during a 60 h on-stream reaction.

N-Heptane isomerization activities of Pt catalyst supported on micro/mesoporous composites

Pt loaded on a series of MCM-48 silica and composites with HZSM-5 zeolite, HY zeolite, or TiO2 has been prepared and studied for n-heptane isomerization reaction at 200–350 °C. The structural characterization, acid distribution, and morphology of these catalysts were characterized by X-ray diffraction, Fourier transform infrared, UV–Vis diffuse reflectance, scanning electron microscope, temperature-programmed desorption of NH3, and nitrogen adsorption–desorption methods. The results show that these catalysts have a good selectivity to multi branched isomers, while producing low aromatic compounds. Also, these new composite catalysts prove the catalytic stability during the time of reaction. The most desirable results, and significantly higher n-heptane conversion and isomerization selectivity were achieved with Pt/MCM48-HZSM5 catalyst.

Comparison of cracking activity of the core-shell composite MCM-41/HY & MCM-48/HY catalysts in the synthesis of organic liquid fuel from Mahua oil

A synergistic catalyst was architectured using the hydrothermal crystallization method. Mesoporous material with pore diameter less than 20 nm was grown on the microporous Zeolite HY. The catalysts were characterized by XRD, ICP-OES, BET, TPD, SEM and TEM techniques. The SEM picture portrayed excellent core – shell morphology and TEM analysis corresponded to the XRD reports. Mahua oil was cracked in a pilot scale reactor over the synthesized catalysts at an optimized reaction condition (Temperature: 400 οC; WHSV: 4.6 h−1). The gaseous and liquid products of reaction were analyzed by Residual Gas analyzer and GCMS respectively. The NMR spectral analysis of fuel showed low traces of aromatics. The produced fuel was analyzed for its significant properties like calorific value, fire point, flash point and viscosity.

Cyclic coupling of photocatalysis and adsorption for completely safe removal of N-nitrosamines in water

The incomplete removal of N-nitrosamines in water through current degraded techniques and the carcinogenicity of N-nitrosamines call for alternative complete and safe removal approaches. Here, we describe a cyclic coupling process of photocatalysis and adsorption enabling N-nitrosamines in water thoroughly and safely removed. Among them, the immobilized TiO2/Ti photocatalyst degraded N-nitrosamines into primary and secondary amines up to 100% by attacking on nitrosyl nitrogen via •OH originated from its nanowire film morphology. Furthermore, the affinity of HY zeolite to primary and secondary amines led to efficient adsorption through corresponding to Lagergren adsorption rate equation of second order. And then the cyclic coupling process of photocatalysis and adsorption realized complete and safe removal of N-nitrosamines with various concentration ranging from 0.1 mM to 1 mM in water, significantly higher than the existing reports on the removal rate of N-nitrosamines and the formation potential of N-nitrosamines. This study will lead to new avenues for complete and safe eliminaton of hardly degradable hazardous substances in water.

Pseudo-Five-Component Reaction for Diastereoselective Synthesis of Butterfly Shaped Bispiro[Oxindole-Pyrrolidine]s.

A pseudo-five-component reaction involving double decarboxylative 1,3-dipolar cycloaddition of azomethine ylides with olefinic oxindoles for the diastereoselective synthesis of bispiro[oxindole-pyrrolidine]s is developed. The major diastereomers are unique butterfly shaped compounds with a plane of symmetry. Recyclable zeolite HY acid catalyst is used to promote the reaction, and only CO2 and H2O are generated as byproducts.

Catalytic co-pyrolysis of wet-torrefied bamboo sawdust and plastic over the zeolite HY: Synergism and kinetics

In this study, the catalytic co-pyrolysis (CCP) of wet-torrefied bamboo sawdust (TB) and linear low-density polyethylene (LLDPE) over zeolites was carried out using the thermogravimetric analyzer. The analysis was carried out at four different heating rates (5–40 °C min−1) and under an inert (Ar) atmosphere. Four degradation stages were observed in the CCP of TB and LLDPE blends, the first stage being moisture removal. The peak decomposition temperature of catalytic pyrolysis (CP) of LLDPE over FAU was reduced by 251 °C as compared to that over HZSM-5 and the enhancement can be attributed to the topology of HY. The activation energies were calculated using isoconversional models: Kissinger–Akahira–Sunose model (KAS), Ozawa–Flynn–Wall model (OFW), and Friedman model (FM). The average activation energies (Eα) of the blends TBL3:1, TBL1:1, and TBL1:3 (TBL: Blend of torrefied biomass and LLDPE) were 171, 128, and 117 kJ mol−1, respectively, using the KAS model. The Eα of the blends was much lower as compared to that of TB, indicating a clear synergism. A multistep mechanism was observed in both CP of individual samples and CCP of blends, as analyzed by Criado's master plot. For example, the CCP of TBL1:3 followed geometric (volume) contraction (R3) and first-order reaction models at low and high conversions, respectively.

Py-GC-MS Study on Catalytic Pyrolysis of Biocrude Obtained via HTL of Fruit Pomace

Herein, we proposed new two-stage processing of blackcurrant pomace toward a value-added, hydrocarbon-rich biocrude fraction. The approach consisted of thermochemical liquefaction of a wet-type organic matter into liquid biocrude followed by its upgrade by thermal and catalytic pyrolysis. Particularly, we put effort into investigating the effect of selected catalysts (ZSM-5 and HY zeolite) on the composition of the volatiles released during the pyrolysis of the biocrude. The latter was obtained through liquefaction of the raw material in the binary solvent system of water and isopropanol. The biocrude yield accounted for ca. 45 wt.% of the initial dry biomass. It was a complex mixture of various component groups with an abundant share of oxygenates, especially carboxylic acids and esters. Thereafter, the biocrude was subjected to a pyrolysis study performed by means of the microscale coupled pyrolysis-gas chromatography-mass spectrometry technique (Py-GC-MS). The dominant components identified in the catalytic pyrolytic volatiles were unsaturated hydrocarbons (both cyclic and aliphatic ones) and, to a lesser extent, oxygen and nitrogen compounds. The addition of the ZSM-5 and HY zeolite allowed us to attain the relative total share of hydrocarbons in the volatile fraction equal to 66% and 73%, respectively (in relation to identified compounds). Thus, catalytic pyrolysis over zeolites seems to be particularly prospective due to the promotion of the deoxygenation reactions, which manifested in the noticeable decrease in the share of oxygen compounds in the evolved volatiles. The developed innovative two-stage processing of blackcurrant pomaces allows for obtaining value-added products that could serve as chemicals, biocomponents, and self-contained biofuels as well as bioplastic precursors. The presented contribution brings some new insights into the field of valorization of residuals generated by the food industry sector.

W Modified HY Zeolite as Catalyst for Alkylation of Aromatic

W Modified HY Zeolite as Catalyst for Alkylation of Aromatic

Investigation of Ni, Co, and Zn promoters on Mo/HY modified zeolite for developing an efficient bimetallic catalyst for oxidative desulfurization of dibenzothiophene

Bimetallic Mo-M (M = Ni, Co, and Zn)/RHY supported catalysts were synthesized for oxidative desulfurization (ODS) of dibenzithiophene (DBT). Recrystallized HY zeolite (RHY) included a superior meso-porous structure (RHY) which is attractive for bulky dibenzothiophene (DBT) elimination. The facilities of M promoters on the Mo/RHY features and activity were investigated. Despite similar ionic radius, different electronegativity of Ni, Co, and Zn transition metals caused to different interaction with Mo and RHY zeolite. The results demonstrated that Ni influenced negatively on dispersion of Mo species over the support, while Co and Zn improved the dispersion. Ni interacted readily with framework Al, leading to extraction of Al, collapse of the zeolite structure, and more octahedral and crystalline Mo species. The formation of MoO3 crystals was inhibited by Zn and Co addition leading to improvement of Mo dispersion. Moreover, Zn- and Co-doped Mo/RHY exhibited higher Lewis acidic sites. The ODS activity decreased in the order of MoZn > MoCo > Mo > MoNi. UV–vis results approved that the most of Mo in the Zn doped sample was non-framework type which can well disperse over the external surface. Meanwhile, Co addition enhanced the tetrahedral Mo species incorporated into the zeolite framework. Allowing more exposed high active Mo species for ODS reaction by Zn promoter, the catalytic performance was boosted. The best catalyst, MoZn/RHY, exhibited 100% DBT removal (t = 30 min, T = 40 °C, catalyst/fuel = 10 g/L, O/S = 10, VSolvent/VOil = 1/2, DBT = 1000 ppm) and a high reusability in 4 consecutive recycles. The highest removal of indole as a nitrogen compound was also achieved by the introduced MoZn/RHY catalyst.

Zeolite-based hybrid material as an efficient promoter in the green synthesis of mono/bis-phthalazinones

Hybrid structures containing organic-inorganic porous materials are of great interest as green, heterogeneous, and recyclable catalysts. In this study, a novel organic-inorganic hybrid material (Zeolite HY@DETA) via the surface-functionalization of the Zeolite HY was prepared. The structure of hybrid material was characterized using the Fourier-transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), Energy-dispersive X-ray spectroscopy (EDS), thermogravimetric analysis (TGA), and Brunauer–Emmett–Teller (BET) surface area analysis. Subsequently, the catalytic activity of this novel hybrid material was considered in the one-pot three-component synthesis of 3-amino-1-aryl-5,10-dioxo-1H-pyrazolo[1,2-b]phthalazine-2-carbonitrile and some bis phthalazine-dione derivatives under green and environmentally benign conditions. The products were synthesized in excellent yields within a short reaction time and identified using elemental analysis, FT-IR, 1H NMR, and 13C NMR spectroscopies. This protocol avoids the use of harmful catalysts, toxic solvents, and harsh reaction conditions. Besides, the catalyst could be recycled for five reaction runs with a slight loss of catalytic activity.

Biodiesel Production using Synthesized HY Zeolite Catalyst

Biodiesel was produced using oleic acid esterification and transesterification of the sunflower oil methods. Many different factors affecting production procedures were studied such as reaction temperature, the molar ratio of ethanol to oil, reaction time and concentration of HY catalyst.
 Different techniques such as TGA, FTIR and Mass spectroscopy were used to syntheses biodiesel. Results showed that 78% of oleic acid maximum conversion was obtained at a temperature of 70oC with molar ratio 12:1 ethanol: oil with 5 wt.% catalysts at 90 min reaction time, while for sunflower oil conversion of 98% at 200oC with 5 weight ratio of ethanol: oil at a time of 3 h was successfully obtained.

Stabilitas Zeolit HY Hidrofobik terhadap Uji Hot Liquid Water (HLW)

Initially, zeolite catalysts cannot be used for reactions involving hot liquid water, so it is necessary to modify the zeolite to be stable under these conditions. The synthesis of HY and hydrophobic zeolites aimed to determine the stability of zeolite in hot liquid water (HLW). The stability of zeolite in HLW is related to zeolite hydrophobicity. In this study, the main raw materials for the synthesis of HY zeolite were sodium aluminate (NaAlO2) and Ludox HS-40 by calcining the product at 350 oC for 1 hour. Furthermore, increasing the hydrophobicity of HY zeolite was carried out by modifying the external zeolite surface using organosilanes (aminopropyltriethoxysilane). The stability of two zeolites in HLW was set at 200 oC. Zeolite analysis used physical test and Fourier Transform-Infra Red (FTIR) Spectrometer. The results of the zeolite distribution in two phases confirmed that HY zeolite was completely dispersed in the water phase, while the zeolite one was dispersed in the organic phase. Moreover, the IR spectra of HY zeolite showed that the wide peak detection at wave number 720 cm-1 for beginning to disappear. This means that the HLW condition could be damaged to the d6r unit. Another result was shown by hydrophobic zeolite spectra with a stable peak for 72 hours. This indicates that the hydrophobic zeolite has thermal stability in HLW so that it can be used in chemical reaction catalytic applications that use on phase.

Near 100% ethene selectivity achieved by tailoring dual active sites to isolate dehydrogenation and oxidation

Prohibiting deep oxidation remains a challenging task in oxidative dehydrogenation of light alkane since the targeted alkene is more reactive than parent substrate. Here we tailor dual active sites to isolate dehydrogenation and oxidation instead of homogeneously active sites responsible for these two steps leading to consecutive oxidation of alkene. The introduction of HY zeolite with acid sites, three-dimensional pore structure and supercages gives rise to Ni2+ Lewis acid sites (LAS) and NiO nanoclusters confined in framework wherein catalytic dehydrogenation of ethane occurs on Ni2+ LAS resulting in the formation of ethene and hydrogen while NiO nanoclusters with decreased oxygen reactivity are responsible for selective oxidation of hydrogen rather than over-oxidizing ethene. Such tailored strategy achieves near 100% ethene selectivity and constitutes a promising basis for highly selective oxidation catalysis beyond oxidative dehydrogenation of light alkane.

Kinetic Study on Microwave-Assisted Oligomerization of 1-Decene over a HY Catalyst

A promising production route for a high-quality base stock for lubricants is the oligomerization of high molecular-weight olefins in a high energy efficiency system. Oligomerization of 1-decene (C10) was conducted in a microwave-assisted system over a HY zeolite catalyst at different reaction temperatures and times. Higher reaction temperature resulted in increasing formation of dimers and trimers. The oligomerization reaction yielded 80% conversion, 54.2% dimer product, 22.3% trimer product and 3.4% heavier product at 483 K for a reaction time of 3 h. The best fit kinetic model for the dimerization reaction was formulated from an assumption of no vacant reaction sites. For the trimerization reaction, a molecule of dimer (C20) formed on the active site, interacted with a molecule of 1-decene in the bulk solution to form a molecule of trimer (C30). Apparent activation energies for the dimerization and trimerization reactions were 70.8 ± 0.8 and 83.6 ± 0.9 kJ/mol, respectively. The C13-NMR spectrum indicated that the oligomer product contained a significant portion of highly branched hydrocarbons, causing a substantial reduction in the viscosity index compared to conventional poly-alpha olefin lubricant (PAO).

Functionalizing HY zeolite with sulfonic acid, a micro-meso structure reusable catalyst for organic transformations

Functionalizing HY zeolite with sulfonic acid, a micro-meso structure reusable catalyst for organic transformations

Catalytic conversion of cellulose and starch to furfural over zeolites

Conversion of cellulose and starch to furfural was investigated over four zeolites. The zeolites were characterized by X-ray diffraction, 27Al MAS NMR, IR spectra of pyridine adsorption and NH3 temperature-programmed desorption. The roles of acidity and pore structure of zeolites in conversion of cellulose and starch were discussed in detail. The results showed that Hβ zeolite with appropriate Brønsted acid sites, Lewis acid sites and pore structure was effective to produce furfural from cellulose and starch. HY zeolite could not catalyze cellulose reaction with high conversion because of its weak acidity. However, HY zeolite was effective to produce 5-hydroxymethylfurfural (HMF) from starch. H-mordenite and HZSM-5 zeolites with fewer Lewis acid sites could not cause the isomerization reaction from glucose to fructose. So, the further conversion of fructose to furfural or HMF was inhibited. The formation of HMF only depended on the acid properties of zeolites. The formation of furfural was not only determined by the acidity of zeolites, but also by their appropriate pore structure.

Toward Excellent Na+ Poisoning Resistance of Fe2O3/HY: The SiO2/Al2O3 Ratio of Zeolite Strongly Matters

Fe2O3/HY zeolite has been recently identified as an efficient alkali-poisoning-resistant catalyst for NOx control by NH3-selective catalytic reduction. The HY zeolite is shown to be the “workhorse”...

A new method of developing ANN-isotherm hybrid models for the determination of thermodynamic parameters in the adsorption of ions Ag+, Co2+ and Cu2+ onto zeolites ZSM-5, HY, and 4A

A new methodology for simultaneous parameter estimation of several adsorption curves through a hybrid ANN-isotherm model is proposed. For that, the ANN model was trained with 36 adsorption isotherm curves with three different adsorbates (Ag+, Co2+, and Cu2+), three different adsorbents (zeolites ZSM-5, HY, and 4A), and four different temperatures. Two ANN-isotherm hybrid models were created. One was based on the Langmuir equation, and the other was based on Sips. A pseudo-outputs method was implemented for isotherm and thermodynamic parameters estimation. The hybrid models reached Pearson's linear correlation coefficient values between 0.98 and 1 for measured and predicted data. The Sips heterogeneity factor indicated that only zeolite 4A performed the adsorption process with a certain heterogeneity degree. In contrast, zeolites ZSM-5 and HY had adsorptions fully described by the Langmuir isotherm. The assessment of adsorption thermodynamic parameters compared the isotherm-based values of equilibrium constant (K) and change in Gibbs' free energy (ΔG0) from the pseudo-outputs ANN structure to Van’t Hoff equations calculated K and ΔG0, showing good agreement with high values of R2 and low values of RMSE. It was also possible to determine that zeolite 4A showed the best adsorption efficiency due to the higher affinity with ions Ag+, Co2+, and Cu2+, followed by zeolite HY. Among the metallic ions, Ag+ and Cu2+ had similar adsorption behaviors onto all adsorbents, with improved adsorption as the temperature increased, while the Co2+ showed the lowest sensitivity to temperature variation.

Direct Synthesis of Liquefied Petroleum Gas from Carbon Dioxide Using a Copper/Zinc Oxide/Zirconia/Alumina and HY Zeolite Hybrid Catalyst

AbstractConversion of CO2 to lower hydrocarbons (HCs) is a high potential process that could reduce and sustainably control this greenhouse gas. In accord with The Sustainable Development Goal from The United Nation Development Program, liquefied petroleum gas (LPG) is viewed as environmentally friendly and is widely used. Small HCs can be directly synthesized from CO2 hydrogenation over a hybrid catalyst. The main purpose of this study was to investigate the direct synthesis of LPG from CO2 hydrogenation using a copper/zinc oxide/zirconium/alumina (CZZA) mixed metal and HY zeolite as a hybrid catalyst. The study was conducted in a fixed bed reactor using hydrogen/CO2/carbon monoxide as the reactant gas and evaluating four types of production condition, method of catalyst combination, reaction temperature, CZZA/HY zeolite mass ratio, and catalyst weight/volume flow rate. The mixing type between the CZZA and HY zeolite catalysts markedly influenced the HC selectivity with strong suppression of reverse water gas shift reaction. At the optimum condition, a 27.39 % CO2 conversion level and a high HC (98.70 %) and LPG (66.56 %) selectivity were obtained.

Sustainable production of benzene from lignin

Benzene is a widely used commodity chemical, which is currently produced from fossil resources. Lignin, a waste from lignocellulosic biomass industry, is the most abundant renewable source of benzene ring in nature. Efficient production of benzene from lignin, which requires total transformation of Csp2-Csp3/Csp2-O into C-H bonds without side hydrogenation, is of great importance, but has not been realized. Here, we report that high-silica HY zeolite supported RuW alloy catalyst enables in situ refining of lignin, exclusively to benzene via coupling Bronsted acid catalyzed transformation of the Csp2-Csp3 bonds on the local structure of lignin molecule and RuW catalyzed hydrogenolysis of the Csp2-O bonds using the locally abstracted hydrogen from lignin molecule, affording a benzene yield of 18.8% on lignin weight basis in water system. The reaction mechanism is elucidated in detail by combination of control experiments and density functional theory calculations. The high-performance protocol can be readily scaled up to produce 8.5 g of benzene product from 50.0 g lignin without any saturation byproducts. This work opens the way to produce benzene using lignin as the feedstock efficiently.