H-beta Zeolite Catalyst Research Articles

H-Beta Zeolite as Catalyst for the Conversion of Carbohydrates into 5-Hydroxymethylfurfural: The Role of Calcination Temperature

H-Beta zeolite is a solid acid catalyst commonly utilized in the catalytic conversion of biomass resources. In this study, H-Beta zeolite was calcined at different temperatures (350, 550, 750, and 1000 °C) to explore the effects of high temperature-induced dealumination on its physicochemical properties and its catalytic ability to convert glucose into 5-hydroxymethylfurfural (HMF). It was shown that as the calcination temperature increased, the Si-O-Al bond of H-Beta zeolite was broken and its dealumination effect was enhanced. Dealumination led to the collapse of the framework of H-Beta zeolite and a reduction in the number of acid sites, which in turn reduced its catalytic performance and the efficiency of HMF formation from glucose. Furthermore, H-Beta zeolite exhibited an extraordinary catalytic ability for the production of HMF from carbohydrates. Using glucose and cellulose as substrates, superior HMF yields of 91% and 46%, respectively, were achieved under optimal reaction conditions. Further, calcination removes carbon deposits in the recovered H-Beta zeolite, but it affects the cycling stability of the catalyst. Meanwhile, the by-products formed during the synthesis of HMF from glucose catalyzed by H-Beta zeolite catalyst were also clearly detected.

Wet torrefaction of biomass waste into levulinic acid and high-quality hydrochar using H-beta zeolite catalyst

Wet torrefaction (WT) is an effective pretreatment method of biomass waste for producing high-quality hydrochar and valuable liquid products. This study delves into how acid catalysts and reaction conditions in WT impact the resulting hydrochar's surface characteristics and elemental composition, as well as the distribution of liquid products. The focus is on utilizing wood cellulose pulp residue (WCPR) as the feedstock with H-Beta zeolite catalyst in a nitrogen-rich environment. The WT process involves a temperature range of 180–260 °C, and reaction durations spanning 15–60 min. The findings reveal that WT conditions, including the catalyst for WCPR, significantly influence the hydrochar's properties and liquid product distribution. With increasing temperature and reaction time, the hydrochar experiences changes, including increased carbon content and reduced oxygen content. The study identifies 260 °C and 30 min as the optimal temperature and time for levulinic acid production, achieving a remarkable selectivity of 62.8% with the H-Beta zeolite catalyst using H2O/WCPR = 10. Various properties of the resulting hydrochar are assessed, including higher heating values (HHVs), decarbonization (DC), dehydrogenation (DH), deoxygenation (DO), enhancement factor, carbon enrichment, surface area, pore diameter, weight loss as well as solid, carbon, hydrogen, and energy yields. The WT + Beta_220 sample, processed at 220 °C for 30 min, exhibited the highest HHV at 30.3 MJ/kg and carbon content at 78.9% in hydrochar compared to various biomass types, with an enhancement factor of 1.51 and carbon enrichment of 1.63, while the sequence of element removal during WT prioritized as DO > DH > DC. Furthermore, it is worth highlighting that the most significant weight loss, increasing from 17.0 to 60.7%, was observed under the same WT conditions. Lastly, a comprehensive reaction pathway is proposed to elucidate the WT of WCPR with the presence of H-Beta zeolite catalyst under these optimized conditions.

Investigation of the Suzuki–Miyaura cross-coupling reaction on a palladium H-beta zeolite with DFT calculations

Metal or metal cluster-doped zeolites catalyse a wide variety of reactions. In this work, a coupling reaction between bromobenzene and phenylboronic acid to yield biphenyl with the Pd–H-Beta zeolite catalyst was investigated with density functional theory (DFT) calculations. Utilizing a model system with tetrahedral Pd4 clusters within the H-Beta zeolite, it was demonstrated that the catalyst exhibited notable reactivity by effectively reducing the activation energy barrier for the reaction. Our investigation revealed that the zeolite framework facilitated electron transfer to the Pd cluster, thereby increasing the reaction activity. The coupling reaction was shown to be exothermic and comprise three main steps: oxidative addition of bromobenzene (C6H5Br), transmetallation with phenylboronic acid (C6H5B(OH)2), and reductive elimination of biphenyl (C12H10). Specifically, in the transmetallation step, which was the rate-determining step, the C–B bond breaking in phenylboronic acid (C6H5B(OH)2) and the phenylboronate anion (C6H5B(OH)3–) were compared under neutral and basic conditions, respectively. This comprehensive study clarifies the mechanism for the reaction with the modified Pd zeolite catalyst and highlights the essential role of the zeolite framework.

Controllable transformation of biomass-derived diols over an ammonia-modified H-Beta zeolite

For the controllable transformation of C3–6 diols in ethylene glycol (EG), a H-Beta zeolite catalyst was modified with NH3via incomplete desorption.

Utilisation of coal tar naphthalene oil fractions for the synthesis of value-added chemicals: alternative paths to mono- and di-methylnaphthalenes

This study investigates the utilisation of coal tar naphthalene oil fraction (CTNOF), an economical by-product derived from the iron-steel industry, for the production of valuable chemicals, with a particular focus on methylnaphthalenes (MNs) and dimethylnaphthalenes (DMNs). Of specific interest is 2,6-dimethylnaphthalene (2,6-DMN), a pivotal component in the manufacture of polyethylene naphthalate (PEN). The intricate and costly nature of 2,6-DMN production currently poses challenges to the commercial viability of PEN. This study provides the potential heterogeneous reaction pathways for the synthesis of MNs and DMNs via methylation, disproportionation, and isomerisation of CTNOF. The utilisation of CTNOF was investigated in a laboratory-scale fixed bed reactor operating at atmospheric pressure using a mixture of CTNOF: methanol having 1:5 mass ratio over HBeta zeolite catalyst at a temperature of 400 °C and weight hourly space velocity of 2 h−1. The results reveal the successful methylation of CTNOF over the HBeta zeolite catalyst, initially achieving high naphthalene conversion, particularly into 2-MN. This highlights the potential of CTNOF as an alternative feedstock for the production of value-added chemicals. While naphthalene conversion initially reaches 99 wt% within 0.5 h of operation, it gradually decreases to approximately 10 wt% over extended run times. Notably, coke deposition significantly deactivates the HBeta zeolite catalyst during CTNOF methylation, impacting naphthalene conversion. A substantial proportion of naphthalene compounds convert to methylnaphthalenes early in the reaction, predominantly 2-MN, increasing from 14 wt% (in CTNOF feedstock) to 87 wt%. Among DMNs, selectivity for 2,6-DMN, 2,7-DMN, 1,3-DMN, and 1,7-DMN increases, while other DMN isomers exhibit a sharp decrease in selectivity. The distribution of 2,6-triad DMNs rises from 38 wt% in feedstocks to 52–55 wt% with extended reaction times, attributed to MN conversion to DMNs and potential isomerisation from other DMNs. This study underscores the feasibility of using CTNOF for the direct synthesis of valuable chemicals, specifically 2,6-DMN and 2-MN, through methylation over HBeta zeolite catalysts. However, it emphasises the critical role of residence time in coke deposition and the need for optimisation, particularly regarding this parameter, to ensure the efficiency of this catalytic process.

Non-waste energy and resource-saving heterogeneous catalytic methods of obtaining and transformation of cyclic acetalies and gem-dichlorocyclopropanes

New methods and ways of using heterogeneous zeolite catalysts – H-Y, H-Beta, H-MOR, H-ZSM-5 and micro- meso-porous – H-Ymmm and others in organic synthesis were studied. Using the example of available petrochemical compounds such as polyols, olefins, and dienes, the possibilities of carrying out cyclization and condensation reactions in the presence of zeolites of various structural types are shown. It has been established that the H-Beta zeolite catalyst provides a quantitative yield of ethers and esters during the interaction of olefins – substituted vinyl-gem-dichlorocyclopropanes – with linear alcohols and acids, respectively. It has been determined that the condensation of styrene and an equimolar mixture of 4-hydroxymethyl-1,3-dioxolane and 5-hydroxy-1,3-dioxane in the presence of the H-Beta catalyst proceeds with the formation of ethers, while the ratio of 5 and 6-membered isomeric products = 1.2:1. Multicomponent condensations successfully proceed in one stage in the presence of wide-pore zeolites.

One‐Pot Selective Synthesis of Renewable p‐Xylene by Completely Biomass‐Based Ethanol and Dimethylfuran with Functionalized Mesoporous MCM‐41

AbstractOne‐pot direct synthesis of renewable p‐xylene (PX) via Diels‐Alder cycloaddition of completely bio‐based ethanol and 2,5‐dimethylfuran (DMF) was studied comparatively over dealuminated HBeta zeolite and functionalized mesoporous MCM‐41. The sulfonic group‐functionalized MCM‐41 had better catalytic performances. Under the optimized conditions, an ethanol conversion of ∼100 %, 2,5‐DMF conversion of 79 % and PX selectivity of 80 % were obtained over NH3‐Silylated‐MCM‐41‐10 %SO3H catalyst with 0.8 wt % N content, which is much better than HBeta zeolite catalyst. X‐ray diffraction (XRD), thermogravimetric analysis (TGA), 29Si cross‐polarization magic‐angle spinning (CP/MAS) NMR and infared (IR) characterizations showed that sulfonic and silylated groups have been successfully grafted onto MCM‐41. Quantitative 1H MAS NMR with d5‐pyridine adsorption unambiguously demonstrated that silylated MCM‐41‐SO3H with NH3 pre‐treatment has much higher amount and stronger strength of Brönsted acid than zeolite catalyst. This is the vital factor to catalyze the dehydration of ethanol to ethylene and speed up the Diels‐Alder cycloaddition reaction, ultimately increase PX selectivity and reduce much less soft‐coke deposit on MCM‐41‐SO3H (∼4 wt %) than on HBeta zeolite (∼12 wt %). This work demonstrates a simple and economical strategy to further improve the potential for the production of sustainable chemicals from complete biomass.

Influence of Natural and H-Beta Zeolites on Yield and Composition of Non-Polar Fraction of Bio-Oil in Slow Co-Pyrolysis of Biomass and Polypropylene

The non-oxygenated fraction of bio-oil is precursor of the formation of biofuel because it contains hydrocarbon only. Zeolite catalysts have been proved to improve the yields of non-polar fraction of bio-oil in case of fast co-pyrolysis. In the present work, the catalysts were applied to slow co-pyrolysis to investigate their effect on the yields and compositions of non-oxygenated fractions of bio-oil. The co-pyrolysis was conducted in a stirred tank reactor using non catalyst (thermal co-pyrolysis), natural zeolite and H-beta zeolite catalysts with heating rate of 5°C/minute from ambient temperature to 500°C and PP composition in combined feed varied 0, 50, and 100% weight of PP. As biomass, the present study used corn cobs. The results show that synergistic effect on the yield of non-oxygenated fraction in co-pyrolysis involving natural zeolite was lower than that in thermal co-pyrolysis and co-pyrolysis involving H-beta-zeolite exhibited negative synergistic effect. H-NMR analysis of the fraction from co-pyrolysis involving 50% weight of PP shows that the bio-oil contained approximately methyl H of about 55% by mol, methine H of 20% and methylene H of about 15% irrespective of catalysts used. This composition was closer to that of commercial gasoline rather than commercial diesel compositions.

Alkylation of Aromatic Hydrocarbons with 2-Methyl-2-Vinyl-gem-Dichlorocyclopropane over Zeolite Catalysts

It has been found as a result of the investigation of the catalytic properties of various microporous zeolites (of FAU, BEA, MOR, and MFI structural types) and a micro–meso–macroporous H-Ymmm zeolite (FAU) in the alkylation reaction of arenes (benzene (II) and toluene (III)) with the unsaturated compound 2-methyl-2-vinyl-gem-dichlorocyclopropane (I) that the reaction proceeds with the formation of chloroalkylarenes [1-(2,2-dichloro-1-methylcyclopropyl)ethyl]benzene (IV) and 1-[1-(2,2-dichloro-1-methylcyclopropyl)ethyl]-4-methylbenzene(V). Compounds IV and V are the most selectively formed over H-Beta (up to 82%) and H-Ymmm (up to 79%) zeolite catalysts with a high conversion of I (from 90% to full). It has been shown that high selectivity for chloroalkylarenes IV and V is achieved at 100°C, an arene : unsaturated compound molar ratio of 8 : 1, a catalyst concentration of 20 wt % of the reaction mass, and a reaction time of 2 h.

Characteristics of H-beta Zeolite Catalyst for Catalytic Decomposition of <i>t</i>-Butyl Mercaptan

Characteristics of H-beta Zeolite Catalyst for Catalytic Decomposition of <i>t</i>-Butyl Mercaptan

Simultaneous deoxygenation, cracking and isomerization of palm kernel oil and palm olein over beta zeolite to produce biogasoline, green diesel and biojet-fuel

Drop-in fuels have aroused great interest for automotive and aeronautical use, constituting the newest area of biofuel research. These fuels do not contain oxygen, like fossil fuels, and require no modifications to engines and distribution infrastructure. In this work, biohydrocarbons were obtained in the distillation ranges of gasoline, diesel and aviation kerosene from palm kernel oil and palm olein in the form of triglycerides or their hydrolysates. A 15% ratio of the thermally activated HBeta zeolite catalyst to the mass of the fatty material was used. Deoxygenation reactions (5 h, 800 rpm, batch reactor) occurred at 350 °C under 10 bar H2 atmosphere to furnish as much as 96% conversion to liquid hydrocarbons. The products were analyzed by FTIR for a rapid quantification of the deoxygenation efficiency using a method developed for this purpose. These products were also characterized by thermal analysis and GC–MS. The freezing temperatures of the biohydrocarbons and their mixtures with fossil aviation kerosene were determined by DSC. The results obtained were very promising, especially considering the relatively mild process conditions as low H2 pressure and catalyst without noble metal and with high reusability.

Kinetic study on catalytic dehydration of 1,2-propanediol and 1,2-butanediol over H-Beta for bio-ethylene glycol purification

1,2-propanediol (PDO) and 1,2-butanediol (BDO) are preferentially dehydrated over the H-Beta zeolite catalyst in the presence of ethylene glycol (EG). The reaction kinetics of diol conversions over H-Beta was studied. The PDO and BDO conversions were found to follow the route of pseudo-first-order reaction (dehydration) or pseudo-second-order reaction (dehydration and acetalization), which was highly dependent on the diol/H-Beta mass ratio. At the ratios <1, aldehydes were the dominant products from the pseudo-first-order reactions. EG dehydration rarely produced acetaldehyde but formed oligomers following pseudo-third-order kinetics. The apparent activation energies (Ea) for PDO and BDO conversions to aldehydes were lower than that of the EG oligomerization (69.9, 54.0, 99.3 kJ/mol, respectively), consistent with the reactivity order of BDO > PDO > EG as evidenced in temperature-programed reaction analysis. At the mass ratios >16–25, acetals were the main products from the pseudo-second-order reactions, and Ea values of PDO and BDO conversions were 153.6 and 120.7 kJ/mol, respectively. The acetalization has a much lower Ea value than that of diol dehydration. The reactions of PDO conversion were first-order with respect to the H-Beta catalyst regardless of the diol/H-Beta mass ratio, indicating that the acetalization follows the Eley–Rideal mechanism.

Diethyl Ether Production during Catalytic Dehydration of Ethanol over Ru- and Pt- modified H-beta Zeolite Catalysts.

In the present study, the catalytic dehydration of ethanol over H-beta zeolite (HBZ) catalyst with ruthenium (Ru-HBZ) and platinum (Pt-HBZ) modification was investigated. Upon the reaction temperature between 200 and 400°C, it revealed that ethanol conversion and ethylene selectivity increased with increasing temperature for both Ru and Pt modification. At lower temperature (200 to 250°C), diethyl ether (DEE) was the major product. It was found that Ru and Pt modification on HBZ catalyst can result in increased DEE yield at low reaction temperature due to increased ethanol conversion without a significant change in DEE selectivity. By comparing the DEE yield of all catalysts in this study, the Ru-HBZ catalyst apparently exhibited the highest DEE yield (ca. 47%) at 250°C. However, at temperature from 350 to 400°C, the effect of Ru and Pt was less pronounced on ethylene yield. With various characterization techniques, the effects of Ru and Pt modification on HBZ catalyst were elucidated. It revealed that Ru and Pt were present in the highly dispersed forms and well distributed in the catalyst granules. It appeared that the weak acid sites measured by NH3 temperature-programmed desorption technique also decreased with Ru and Pt promotion. Thus, the increased DEE yields with the Ru and Pt modification can be attributed to the presence of optimal weak acid sites leading to increased intrinsic activity of the catalysts. It can be concluded that the modification of Ru and Pt on HBZ catalyst can improve the DEE yields by ca. 10%.

A Comparative Study of Different Al-based Solid Acid Catalysts for Catalytic Dehydration of Ethanol

In this present study, the catalytic dehydration of ethanol over three different Al-based solid acid catalysts including H-beta zeolite (HBZ), modified H-beta zeolite with γ-Al 2 O 3 (Al-HBZ) and mixed γ- χ phase of Al 2 O 3 (M-Al) catalysts was investigated. The ethanol dehydration reaction was performed at temperature range of 200 to 400 o C. It revealed that all catalysts exhibited higher ethanol conversion with increased temperatures. At low temperatures (ca. 200 to 250 o C), diethyl ether (DEE) was obtained as a major product for all catalysts. However, with increased temperatures (ca. 300 to 400 o C), ethylene was a major product. Among all catalysts, HBZ exhibited the highest ethanol conversion giving the ethylene yield of 99.4% at 400 o C. This can be attributed to the largest amount of weak acid sites present in HBZ, which is related to the Bronsted acid. It should be mentioned that HBZ also rendered the highest yield of DEE (ca. 35.3%) at 250 o C. As the results, HBZ catalyst is promising to produce ethylene and DEE from ethanol, which is considered as cleaner technology.

Activity enhancement of Nafion resin: Vapor-phase carbonylation of dimethoxymethane over Nafion-silica composite

A kind of composite materials consisting of nano-sized Nafion resin homogeneously dispersed in a high-surface silica matrix was prepared by sol–gel method and used as catalysts in the vapor-phase carbonylation reaction of dimethoxymethane for production of methylmethoxy acetate. These composite catalysts showed much higher catalytic activity in comparison with the original pure Nafion resin catalyst. The remarkable improvement of catalytic performance was due to the increased accessibility of acid sites of Nafion resin in the composite catalysts. The contents of Nafion-H resin and silica precursors were found to have a great influence on the structure of the composite, resulting in different catalytic activity during DMM carbonylation reactions. Furthermore, the comparison of the composite catalysts with high-silica H-Y and H-Beta zeolite catalysts demonstrated that the excellent catalytic performance is closely related to the higher acid strength and larger pores of Nafion-silica composite materials.

Products of direct hydroalkoxylation of norbornene with alcohols over H-beta zeolite catalyst

The reaction of direct hydroalkoxylation of norbornene in the presence of H-beta zeolite catalyst has been studied. It has been found that the selectivity for exo-alkoxynorbornanes of the reaction of norbornene with monohydric alcohols (saturated, unsaturated, or aromatic) reaches 98% at a conversion of 78–98% of the unsaturated compound. The reaction of norbornene with diols (ethylene glycol and 2-butene-1,4-diol) in the presence of H-beta zeolite affords mono- and diethers, whose yield and ratio can be controlled by varying reaction parameters.

Thermo-catalytic pyrolysis of waste polyethylene bottles in a packed bed reactor with different bed materials and catalysts

Plastic waste is an increasing economic and environmental problem as such there is a great need to process this waste and reduce its environmental impact. In this work, the pyrolysis of high density polyethylene (HDPE) waste products was investigated using both thermal and catalytic cracking techniques. The experimental work was carried out using packed bed reactor operating under an inert atmosphere at 450°C. Different reactor bed materials, including sand, cement and white clay were used to enhance the thermal cracking of HDPE. In addition, the catalytic effect of sodium hydroxide, HUSY and HBeta zeolite catalysts on the degradation of HDPE waste was also investigated. The reactor beds were found to significantly alter the yield as well as the product composition. Products such as paraffins (⩽C44), olefins (⩽C22), aromatics (⩽C14) and alcohols (C16 and C17) were obtained at varying rates. The highest yield of liquid (82%) was obtained over a cement powder bed with a paraffin yield of 58%. The yield of paraffins and olefins followed separate paths, for paraffins it was found to increase in the order or Cement>White clay>Silica Sand, whereas for the olefins it was in the reverse order Silica Sand>White clay>Cement. The results obtained in this work exhibited a higher P/O ratio than expected, where the amount of generated paraffins was greater than 60% in most cases. Less olefin was generated as a consequence. This indicates that the product generated is more suited to be used as a fuel rather than as a chemical feedstock. The carbon chain length was narrowed to C10–C28 when the zeolitic catalysts were employed, as well as a significant yield of aromatics was obtained mainly naphthalene and d-limonene as an indication that the products obtained are fuel-like products.

Carbonyl-ene Reaction of Styrene Derivatives Catalyzed by H-beta Zeolite in Water

The carbonyl-ene reaction of olefin with formaldehyde is an important reaction in organic synthesis. In this study, the carbonyl-ene reaction of olefin with formalin was carried out in water, using H-beta zeolite as a solid acid catalyst. H-beta zeolite was found to be an effective catalyst for the carbonyl-ene reaction of styrene with formalin at a reaction temperature of 90 °C to produce 4-phenyl-1,3-dioxane derivatives in excellent yield, and for the carbonyl-ene reaction of α-methylstyrene with formalin at a reaction temperature of 20 °C to produce homoallylic alcohol with good selectivity. The H-beta zeolite catalyst could be easily recovered and reused.

Methylation of benzene by methanol: Single-site kinetics over H-ZSM-5 and H-beta zeolite catalysts

Benzene methylation by methanol is studied on acidic zeolites H-ZSM-5 (MFI) and H-beta (BEA) to investigate the influence of the catalyst topology on the reaction rate. Experimental kinetic measurements at 350°C using extremely high feed rates to suppress side reactions show that methylation occurs considerably faster on H-ZSM-5 than on H-beta. Theoretical rate constants, obtained from first-principles simulations on extended zeolite clusters, reproduce a higher methylation rate on H-ZSM-5 and provide additional insight into the various molecular effects that contribute to the overall differences between the two catalysts. The calculations indicate this higher methylation rate is primarily due to an optimal confinement of the reacting species in the medium pore material. Co-adsorption of methanol and benzene is energetically favored in H-ZSM-5 compared with H-beta, to the extent that the stabilizing host–guest interactions outweigh the greater entropy loss upon benzene adsorption in H-ZSM-5 vs. in H-beta.

Role of nanosized oxide in catalysis on the nanoporous surface of zeolite particles

Based on our studies on the hybrid catalysts of nanosized (ns) oxide with zeolite, products obtained from the isomerization and hydrocracking of heavier n-paraffins and the role of ns oxide were investigated using a tricomponent catalyst of [Ni-Mo/γ-Al2O3], ns oxide, and H-beta zeolite catalyst, which showed high activity, high isomerization selectivity, and mild cracking ability. A concerted effect of the three components was observed. From the observed hybridization state of the catalyst, it was suggested that the concerted effect was obtained because the components become attached to each other. The individual and concerted effects of each component and two components, respectively, were investigated based on the ratio of [Ni-Mo/γ-Al2O3]/[H-beta zeolite], the content of ns oxide, the amount of metal, the type of ns oxide species, and the reduction state of metal. It was confirmed that in order to obtain the highest concerted effect, the ratios of [Ni-Mo/γ-Al2O3]/[H-beta zeolite] and/or ns oxide/zeolite are important. Furthermore, among the ns oxide species, nsAl2O3-nsTiO2 displayed the highest activity and cracking ability with an over-cracking suppression. In addition to increasing the concerted effect in the tricomponent catalyst, the performance of this catalyst could also be further increased by controlling the amount and reduction state of metal.