Industrial Preparation and Acid Resistance of Ultra-stable Y Zeolite with Small Cell Size Produced by Gas-phase Method

Small-cell HSY-S zeolite prepared by the gas-phase ultra-stable method had been researched and developed,and industrial preparation tests of HSY-S have been successfully carried out for the first time.The acid resistance of industrially prepared HSY-S was investigated by acid solutions with different pH values.The structures and properties of HSY-S and its acid-treated samples were characterized by XRD,XRF,BET,and IR.Results show that the HSY-S samples have the characteristics of high crystallinity,good stability,large specific surface area,and good acid resistance.

Study on Modification of Ultra-Stable Zeolite Prepared by Hydrothermal Method

The ultra-stable zeolite DASY-0.0 was prepared by hydrothermal method in commercial scale. Its structure was further modified via the treatment for cleaning of pores （CP）. The zeolite samples before and after CP treating were analyzed and characterized by XRF, XRD, NMR, IR, BET and DTA. The results showed that, in comparison with the conventional ultra-stable zeolite DASY-0.0 prepared by the hydrothermal process, the CP-modified zeolite SOY0 exhibited a higher relative crystallinity, a larger surface area and pore volume, a higher thermal stability and contained less amorohous non-framework A1.

Development and Catalytic Cracking Performance of Ultrastable Y Zeolite Rich in Secondary Pores

A novel ultra-stable zeolite, NSZ, rich in secondary pores was developed through the combination of gas-phase andmild hydrothermal methods. This zeolite was successfully tested in an industrial setting for the first time in the world. The porestructure characteristics of the NSZ zeolite prepared for industrial use were analyzed and characterized using BET. The resultsindicate a significant increase in the secondary pore volume of NSZ zeolite compared to the existing ultra-stable zeolite HSZ-5, which is produced through a conventional gas-phase method. The average secondary pore volume to total pore volume ratioin NSZ zeolite was found to be 58.96% higher. The catalytic cracking performance of NSZ zeolite was evaluated. The resultsshowed that the NSC-LTA catalyst, with NSZ as the active component, outperformed the HSC-LTA catalyst with HSZ-5 zeolitein terms of obtaining more high-value products (gasoline and liquefied petroleum gas) during the hydrogenated light cycle oilprocessing. Additionally, the NSC-LTA catalyst showed a significant improvement in coke selectivity.

Ag^(+)、Zn^(2+)、Cr^(3+)改性Y型分子筛吸附脱除喹啉的模拟计算研究

首先考察了吸附时间对三种改性Y型分子筛AgY、ZnY、CrY吸附脱除模拟燃料中喹啉的影响,结果发现三种分子筛对喹啉的吸附容量和去除率大小顺序均为:AgY>CrY>ZnY.运用Materials Studio软件,采用巨正则蒙特卡洛(GCMC)和密度泛函理论(DFT)对改性Y型分子筛吸附喹啉机理进行了模拟计算研究,得出以下结论:模拟计算AgY、ZnY、CrY的比表面积和孔体积与其低温N2吸附-脱附表征结果基本一致,并且发现改性Y型分子筛的吸附脱氮能力与比表面积和孔体积关系不大;以Fukui函数为基础,采用Mulliken和Hirshfeld两种布局数分析方法模拟计算了三种改性Y型分子筛的相对亲电性并分析Lewis酸强弱,其Lewis酸大小顺序为:AgY>CrY>ZnY;对三种改性分子筛进行了前线轨道分析,其化学吸附活性大小为AgYCrY>ZnY,模拟计算所得各种结果与实验结果顺序完全一致.

NiMo/Al_2O_3 catalyst containing nano-sized zeolite Y for deep hydrodesulfurization and hydrodenitrogenation of diesel

Two mixed-matrix NiMo/Al2O3 catalysts containing nano-and micro-sized zeolite Y have been prepared to explore the size effect of zeolite Y particle on the hydrodesulfurization（HDS）and hydrodenitrogenation（HDN）activities of fluid catalytic cracking（FCC）diesel.They were characterized by SEM,BET,XRD,H2-TPR,NH3-TPD and HRTEM.The results show that the catalyst containing nano-sized zeolite Y possesses larger average pore diameter,higher pore volume,weaker and lesser acid sites,more easily reducible metal phases,shorter MoS2 slabs and more slab layers than the catalyst containing micro-sized zeolite Y.The catalysts were also evaluated with a high-pressure fixed-bed reactor using real FCC diesel as feed.The results display that the catalyst containing nano-sized zeolite Y bears higher HDS and HDN activities and exhibits higher relative rate constant for the removal of total sulfur or nitrogen than the one containing micro-sized zeolite.

Isomerization of linear C5–C7 over Pt loaded on protonated fibrous silica@Y zeolite（Pt/HSi@Y）

A novel fibrous silica Y zeolite (HSi@Y) loaded with Pt has been studied based on its ability to produce protonic acid sites originating from molecular hydrogen. The Pt/HSi@Y was prepared using seed assisted crystallization followed by protonation and Pt-loading. The product formed had a spherical morphology with bicontinuous lamellar with a diameter in the range of 500-700 nm. The catalytic activity of the Pt/HSi@Y has been assessed based on light linear alkane (C5-C7) isomerization in a micro-catalytic pulse reactor at 423-623 K. A pyridine IR study confirmed that the introduction of fibrous silica on Y zeolite increased the Lewis acid sites corresponding with the formation of extra-framework Al which led to the generation of more protonic acid sites. A hydrogen adsorbed IR study showed that the protonic acid sites which act as active sites in the isomerization were formed via dissociative-adsorption of molecular hydrogen releasing electrons to the nearby Lewis acid sites. Thus, it is suggested that the presence of Pt and HSi@Y with a high number of Lewis acid as well as weak Bronsted acid sites improved the activity and stability in C5, C6 and C7 isomerization via hydrogen spill-over mechanism.

Preparation, Characterization and Catalytic Behavior of 12-Molybdophosphoric Acid Encapsulated in the Supercage of Cs^＋-exchanged Y Zeolite

In order to solve the serious leaching problem of supported heteropoly acid catalysts in polar reaction media, 12-molybdophosphoric acid encapsulated in the supercage of Cs^＋-exchanged Y zeolite was prepared by the ＂ship in the bottle＂ synthesis. The influence of ion-exchange conditions and the synthesis parameters on the encaosulation of PMo12 were investigated. The obtained solid sample was characterized by X-ray diffraction （XRD）, 31p magic angle spin nuclear magnetic resonance （MAS NMR） and Fourier Transform Infrared Spectroscopy （FT-IR）, and its catalytic activity in the esterification of acetic acid and n-butanol was tested. The ion-exchange time, concentration of aqueous Cs^＋ solution, pH value, and amount of Mo added in the synthesis mixture were revealed to influence the encapsulation very remarkably. Under the optimal conditions, 12-molybdophosphoric acid could be successfully encapsulated in the supercage of CsY zeolite, and the samples showed considerable catalytic activity and excellent reusability in the esterification reaction.

Effective adsorptive denitrogenation from model fuels over yttrium ion-exchanged Y zeolite

The adsorption removal of indole and quinoline in octane with and without toluene over zeolites NaY and Yttrium Ion-exchanged Y(YY)using batch adsorption experiments was studied at 25℃and 0.1 MPa.YY was prepared by treating NaY with Y(NO3)3 solution twice via liquid ion-exchange method.NaY and YY were both characterized by XRD,SEM,N2 adsorption,XRF,NH3-TPD,and pyridine-FTIR techniques.Adsorption isotherms of indole,quinoline and toluene in octane were conducted at 25.0℃to explain the influence of toluene on nitrogen removal over NaY and YY.The partial destruct of the crystalline structure of NaY was observed after the introduction of yttrium ion,which led to an evident decline in BET surface area and pore volume of YY.Strong Br?nsted acidity and medium Lewis acidity were introduced by yttrium ion-exchange.Though the specific surface area and pore volume of YY were much lower than those of NaY,YY exhibited equivalent adsorption capacities for indole and quinoline as NaY in model fuels without toluene.In the presence of 20 vol%toluene,however,YY exhibited much higher adsorption capacities for indole and quinoline than NaY,especially in the case of quinoline.The improved toluene-tolerant of YY was ascribed to the strong acid–base interaction between YY and quinoline and the decreased adsorption strength between YY and toluene.

Synthesis of mesoporous high‐silica zeolite Y and their catalytic cracking performance

Mesoporous high‐silica zeolite Y with advantages of improved accessibility of acid sites and mass transport properties is highly desired catalytic materials for oil refinery,fine chemistry and emerg‐ing biorefinery.Here,we report the direct synthesis of mesoporous high‐silica zeolite Y(named MSY,SiO_(2)/Al2O_(3)≥9.8)and their excellent catalytic cracking performance.The obtained MSY mate‐rials are mesoporous single crystals with octahedral morphology,abundant mesoporosity and ex‐cellent(hydro)thermal stability.Both the acid concentration and acid strength of H‐form MSY are obviously higher than those of commercial ultra‐stable Y(USY),which should be attributed to the uniform Al distribution of MSY zeolite.The H‐MSY displays an obviously reduced deactivation rate and improved catalytic activity in the cracking reaction of bulky 1,3,5‐triisopropylbenzene(TIPB),as compared with its mesoporogen‐free counterpart and USY.In addition,H‐MSY was investigated as catalyst for the cracking of industrial heavy oil.The MSY‐based catalyst(after aging at 800 oC in 100%steam for 17 h)exhibits superior conversion(7.64%increase)and gasoline yield(16.37%increase)than industrial fluid catalytic cracking(FCC)catalyst under the investigated conditions.

Kinetics study and analysis of zeolite Y destruction

A series of zeolites,including USY zeolites without sodium,Na-USY at different Na contents,La-USY with different rare earth（RE） contents and La-Na-USY with RE and Na were prepared by an ion exchange method.They were investigated to understand the activation barriers for the destruction of Y zeolite structure under hydrothermal treatment and the effect of V using the solid-state kinetic model.The results showed that the pathways for Y zeolite destruction were dealumination,desiliconization and the disappearance of La-O bonds.Zeolites were destroyed by steam through acid hydrolysis,which was accelerated by V.In addition,Na and V exerted a synergistic effect on the framework destruction,and the formation of NaOH was the rate-determining step.The presence of RE elements decreased hydrolysis and stabilized the structure of the zeolites.The interaction between V and RE destroyed zeolite structure by eliminating the stabilizing La-O[RE-OH-RE]^（5＋）bridges in the sodalite cages.

High-silica faujasite zeolite-tailored metal encapsulation for the low-temperature production of pentanoic biofuels

Zeolite-encapsulated metal nanoclusters are at the heart of bifunctional catalysts,which hold great potential for petrochemical conversion and the emerging sustainable biorefineries.Nevertheless,efficient encapsulation of metal nanoclusters into a high-silica zeolite Y in particular with good structural integrity still remains a significant challenge.Herein,we have constructed Ru nanoclusters(~1 nm)encapsulated inside a high-silica zeolite Y(SY)with a SiO_(2)/Al_(2)O_(3) ratio(SAR)of 10 via a cooperative strategy for direct zeolite synthesis and a consecutive impregnation for metal encapsulation.Compared with the benchmark Ru/H-USY and other analogues,the as-prepared Ru/H-SY markedly boosts the yields of pentanoic biofuels and stability in the direct hydrodeoxygenation of biomass-derived levulinate even at a mild temperature of 180℃,which are attributed to the notable stabilization of transition states by the enhanced acid accessibility and properly sized constraints of zeolite cavities owing to the good structural integrity.

Effect of metal content on the activity and product selectivity of n-decane hydroisomerization over Ni-Pd/HY zeolite

Metal-loaded zeolite catalysts were synthesized and examined in the hydroisomerization of n-decane.Specifically,zeolite Y was impregnated with 0.1 wt%Pd and varying amounts of Ni（0.1-0.5 wt%].The crystallinity of the metal-loaded catalysts was characterized by X-ray diffraction,and the average metal particle size was determined by transmission electron microscopy.The states of Pd and Ni were identified by X-ray photoelectron spectroscopy.Ammonia temperature-programmed desorption analysis revealed the occurrence of ion-exchange of some of the catalyst acid sites with Ni-（2＋）.The reducibility of the HY zeolite-supported Pd,Ni,and Pd-Ni catalysts was studied by temperature-programmed reduction.The hydroisomerization of n-decane over the prepared catalyst was conducted at 200-450℃ under 1 atm.Ni addition of up to 0.3 wt%over 0.1 wt%Pd/HY enhanced the n-decane conversion and isomerization product selectivity.The improved selectivity of the mono- and dibranched isomers suggested the occurrence of a protonated cyclopropane intermediate mechanism.However,further Ni addition above 0.3 wt%considerably reduced the activity and isomerization selectivity.The bimetallic catalysts were more selective toward the formation of dibranched isomers,i.e.,those containing a higher octane number.

Structural Changes of Y Zeolites with Different Initial SiO_2/Al_2O_3 Ratios during Hydrothermal Treatment

The effects of the initial framework SiO2/Al2O3 ratio and temperature on the structural changes of NaY zeolites during hydrothermal treatments are studied. Two samples with different framework SiO2/Al2O3 ratios are subjected to hydrothermal treatment at four different temperatures. For zeolite with a lower initial SiO2/Al2O3 ratio of 4.2, mesopores are easily formed because more framework aluminum is detached. Moreover, two kinds of mesopores are produced at a higher temperature due to the interconnection of vacancies and smaller mesopores. For zeolite with a higher initial SiO2/Al2O3 ratio of 6.0, there are less mesopores formed as compared with the lower initial SiO2/Al2O3 ratio sample, but there are some macropores formed. This may be attributed to the isolation of vacancies and the different distributions of aluminum in the crystal lattice of the zeolite. The experiment data show that NaY with the SiO2/Al2O3 ratio of 6.0 retains a high relative crystallinity during the hydrothermal treatment. This proves that a high framework SiO2/Al2O3 ratio benefits the stability of zeolite.

Investigation of the Ion-Exchange Behavior of Zeolite Y in the Presence of Resin

Ion-exchange process of zeolite Y using ammonium-type resin as an exchange reagent was successfully carried out. The effect of temperature, space velocity and ion concentration on the breakthrough curves was carefully investigated. At the first exchange section, the maximum proportion of qualified zeolites(QR) was obtained at a temperature of 70 ℃, a weight hourly space velocity of 0.61 h-1, and an ion concentration of 197 mg/L. The minimum length of mass-transfer zone(MTZ) of the resin bed was achieved at a temperature of 70 ℃, a space velocity of 0.61 h-1, and an ion concentration of 423 mg/L. At the second exchange section, the length of MTZ of the resin bed was significantly increased, and the exchange of Na+ ions contained in zeolite Y was more difficult than that achieved at the first exchange section. In both the first and the second exchange sections, the zeolite Y subjected to ion exchange with the resin maintained the similar physical and chemical properties as compared to those exchanged by the conventional approaches, but the zeolite Y, which was obtained after ion exchange, contained a significantly lower content of Na2 O.

H-Y-zeolites induced heterocyclization:Highly efficient synthesis of substituted-quinazolin-4(3H) ones under microwave irradiation

A highly efficient synthesis of 2-amino-N-substituted-benzamides was performed by the condensation ofisatoic anhydride with several amines in solvent-free conditions under microwave irradiation. H-Y-zeolites induced heterocyclization of these products with ortho-esters under similar conditions afforded the relevant substituted-quinazolin-4（3H）ones in high yields.

Adsorption Thermodynamics and Diffusion Kinetics of PX over Na Y Zeolite Synthesized by In-Situ Crystallization from Kaolin Microsphere

Para-xylene was chosen as the probe molecule to study adsorption thermodynamics and diffusion kinetics on NaY zeolite and composite structured NaY zeolite synthesized by in-situ crystallization from kaolin microsphere(designated as Na Y/kaolin composites) separately, using a high precision intelligent gravimetric analyzer(IGA). The adsorption isotherms showed normal Langmuir type-Ⅰ behaviors. The increased adsorption heat with an increasing p-xylene coverage supported a mechanism of phase transition, diffusion and re-arrangement of p-xylene molecules during the adsorption process. The rearrangement seemed to be most pronounced at an adsorption loading of 2.13 and 2.29 mmol/g for Na Y zeolite and Na Y/kaolin composites respectively. Compared with Na Y zeolite, a 2—3 times higher in the diffusion coefficient of p-xylene was observed on Na Y/kaolin composites when the pressure was more than 50 Pa. Temperature-programmed desorption(TPD) of p-xylene on two samples from room temperature to 450 ℃ at a special loading has also been investigated by IGA. Results showed only single desorption peak appeared for Na Y zeolite, indicating that adsorption can only occur in the super-cage structure. Comparably, there were two different peaks for in-situ synthesized Na Y zeolite, corresponding to the two thermo desorption processes in both super-cage structure and the channels provided by kaolin, respectively.Key words:

Different Influences of Lanthanum and Cerium on Stability of Y Zeolite and Their DFT Calculations

In this paper,the different influences of lanthanum (La) and cerium (Ce) species on the stability of Y zeolite were studied by X-ray diffractometry (XRD),X-ray photoelectron spectroscopy (XPS),and multinuclear (27Al,29Si) solidstate nuclear magnetic resonance spectroscopy (NMR).It was found that the stability of Y zeolite could be enhanced by the introduction of La or Ce species;however,the former effect was more remarkable than the latter.These results were also confirmed theoretically by density functional calculations.There was a strong interaction between the rare earth (La or Ce) species and Y zeolite clusters,which restrained the formation of extra-framework aluminum and enhanced evidently the stability of Y zeolite.Furthermore,the interaction between La species and Y zeolite was stronger than that of Ce species with Y zeolite.

Y Zeolites Modified by Organosilane for Toluene Adsorption under High Humidity Condition

Y zeolites have moderate microporous pore size, large specific surface area, and good hydrothermal stability, which were widely used in industrial adsorption of volatile organic compounds (VOCs), but the performance of Y zeolites in adsorption of VOCs under high humidity conditions is terrible. In this paper, Y zeolites with different silica-alumina ratios were hydrophobically modified by organosilane and characterized by XRD, FTIR, SEM, BET, NMR. In the experiments of static and dynamic adsorption of VOCs by modified Y zeolites, it can be concluded that the static water adsorption capacity of Y zeolites with silica-aluminum ratio of 5 and 40 after silica modification decreased by 62 wt% and 53 wt%, under the conditions of high humidity, GHSV = 15,000 h-1, T = 35°C and initial concentration of toluene C0 = 5000 mg·m-3. The saturation adsorption capacity of toluene was increased from 0.06 g·g-1, 0.09 g·g-1 to 0.15 g·g-1, 0.21 g·g-1, the adsorption selectivity of Y zeolites for water was reduced and that for toluene was increased after Vapor phase silanization overlay modification. The present modification method might carry out targeted modification of zeolites surface, provide research ideas and guidance under high humidity conditions.

Hydrothermal Chemistry Involved in Developing Practical Y Type Zeolite Catalysts

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