Alcohol Ether Research Articles

Synthesis of Polyether Ester Plasticizer and Its Application Performance in Hydrogenated Nitrile Butadiene Rubber

ABSTRACTFour polyether ester plasticizers containing both ester groups and ether bonds were synthesized using 1,4‐butanediol, adipic acid, and alkyl ether alcohols as raw materials. By varying the type of end‐capping alcohol ether, the following plasticizers were prepared: poly (butylene adipate dibutyl ether) (PBADBE), poly (butylene adipate butyl ether) (PBABE), poly (butylene adipate dimethyl ether) (PBADME), and poly (butylene adipate methyl ether) (PBAME). These plasticizers were characterized by Fourier transform infrared (FTIR) spectroscopy, proton nuclear magnetic resonance spectroscopy (1H‐NMR), and thermogravimetric (TG) analysis. Furthermore, their differences in cold resistance, heat resistance, and physical‐mechanical properties in hydrogenated nitrile‐butadiene rubber (HNBR) were investigated. The results showed that among the rubber compounds containing the four polyether‐ester plasticizers, the compound with PBADME demonstrated superior heat resistance and low‐temperature performance. Specifically, the PBADME‐containing compound exhibited a TR10 temperature of −39.9°C and a brittleness temperature of −54°C. This significantly broadened the operating temperature range of the plasticizer, making it suitable for applications requiring both high‐temperature and low‐temperature performance.

ЦИКЛИЧЕСКИЕ АЦЕТАЛИ И КЕТАЛИ – ЦЕННЫЕ ПРЕКУРСОРЫ В ОРГАНИЧЕСКОМ СИНТЕЗЕ

Acetals and ketals are a latent form of carbonyl compounds and important intermediates in synthetic and carbohydrate chemistry. There is probably not a single scheme for the synthesis of biologically active compounds in which the technique with diol protection of the carbonyl function has not been used at least once. This is due to the convenience of both setting up the protective group and removing it. Classical synthesis involves the addition of alcohols to aldehydes and ketones in slightly acidic or basic solutions. Before the stage of formation of hemiacetals, the reaction is catalyzed by both acids and bases. However, the conversion of a hemiacetal to an ace- tal occurs only under conditions of acid catalysis and proceeds via the SN1 mechanism through the stage of for- mation of a carbocation from the intermediate hemiacetal. Cyclic acetals and ketals can be classified according to the structure of the ketal center: external (1,3- dioxolane and 1,3-dioxane) and internal. Internal ketals and acetals are cyclic compounds formed from 1,4- and 1,5-oxyaldehydes and oxyketones in the presence of anhydrous acids. Prominent representatives of internal ketals and acetals are carbohydrates and bicyclic ketals containing an adjacent C-C bond at the site of which there is a ketal center, for example, chromanes – bicyclic ketals or hemiketals. Optically active cyclic acetals and ketals are prepared by reacting aldehydes or ketones with chiral diols in three ways. The classic method is to boil the corresponding aldehyde or ketone with alcohol, azeotropically re- moving water in a Dean-Stark apparatus. In α,-enones, to protect the keto group and eliminate the side reaction – migration of the double bond, an alternative approach is used, the Noyori method, which involves the use of disilyl ethers of chiral alcohols. In the case when the initial carbonyl compounds are unstable or are in the form of dimethoxyketals or acetals, the method of transketalization or acetalization is used. Chiral diols are used as alco- hol components, for example, 2,3-butanediols, 2,4-pentanediols, hydrobenzoins. They are capable of attaching nucleophiles and are prone to various rearrangements at acetal and ketal cen- ters. The value of bicyclic hemiketals lies in their use in the synthesis of lactones of various ring sizes. This re- view is devoted to these and some other chemical transformations of cyclic acetals and ketals.

UNUSUAL TRANSFORMATIONS OF 2,3- AND 1,3- BUTHANEDIOL MONOPROPARGYL ETHERS

Research in the field of chemistry of oxygen-containing derivatives of acetylene has acquired considerable interest. Of the simple ethers containing a triple carbon-carbon bond, ethynyl and propargyl ethers of monohydric alcohols and phenols, as well as alkyl and aryl ethers of acetylene glycols have been studied in most detail. Alkynyl, especially propargyl mono- and diesters of polyhydric alcohols have not been studied extensively. Due to the presence of highly reactive centers, ethers occupy a special place in the field of chemistry of oxygen-containing derivatives of acetylenes. Acetylene ethers of glycols usually form ketoxy esters under conditions of acid-catalytic hydration. Using the tendency of propargyl compounds to prototropy in a basic medium, we studied under these conditions the possibility of converting monopropargyl ethers of 2,3- and 1,3-butanediols into oxygen-containing heterocycles. The available data indicate that these types of triple-bonded ethers are of great interest, both theoretically and practically. Among acetylenic ethers of polyhydric alcohols, which are the most interesting class of oxygen-containing alkynes in terms of synthesis and practice, propargyl ethers of acyclic glycols have been studied. In this regard, we have undertaken an experimental study of the synthesis routes of mono- and dipropargyl ethers of glycols and their unusual transformations. Acetylene ethers have proven themselves to be very valuable substances used in various fields of organic synthesis and exhibiting interesting properties of applied nature. Propargyl mono- and diesters of polyhydric alcohols with a triple bond are of great interest, both theoretically and practically. The paper presents the results of a study of acid-catalytic intramolecular cyclohydration and the synthesis of heterocyclic compounds based on propargyl ethers of glycols. The latter were monopropargyl ethers of 2,3- and 1,3-butanediols (I, II). The structure of the obtained heterocyclic compounds was confirmed by NMR and IR absorption spectra. Keywords: cyclohydration, monopropargyl ethers, heterocyclization, butanediols, spectrum, dioxane, t-BuO, NaOH.

Thermal Behavior of n-Octanol and Related Ether Alcohols.

The thermal behavior of n-octanol and related ether alcohols has been studied by differential scanning calorimetry (DSC). The melting point, heat of fusion, and isobaric heat capacities of n-octanol obtained from the DSC measurements are in good agreement with literature values. The ether alcohols display kinetic barriers for forming a solid phase during cooldown. These barriers are least for 6-methoxyhexanol that forms a solid upon cooling except for the highest measured temperature change rate of 40 K·min-1, followed by 4-propoxybutanol that forms a solid during cooldown only at low cooling rates. 2-Pentoxyethanol and 5-ethoxypentanol form a solid during the heating cycle that then melts again upon further heating. 3-Butoxypropanol does not display any exo- and endothermic features for all measured temperature change rates. Consequently, new data on melting point and heats of fusion are reported for the ether alcohols except for 3-butoxypropanol. New isobaric heat capacities are presented as well for the liquid phase of these ether alcohols.

Synergistic effects of mediated by different 1,2-epoxybutane addition numbers butoxylated alkyl block alcohol ethers and SDS in mixed systems

In this study, nonionic surfactant butoxylated alkyl block ether (AE9Bn) and anionic surfactant sodium dodecyl sulphate (SDS) with different BO additions were mixed at different molar ratios to make a hybrid system. The interaction parameters and aggregation behaviors of the blended systems were investigated by observing the average direct particle drop distribution and microscopic aggregates in combination with the results of static surface tension tests of the blended systems. The diffusion process of the mixed systems was investigated using dynamic surface tension tests. The dynamic contact angle and foam properties of the solutions of the mixed systems were also studied. Finally, based on the experimental results, it was concluded that the mixed system of AE9Bn (n=2,5) and SDS formed a synergistic effect that significantly led to a decrease in CMC, with an increase in the number of BO additions leading to a more significant decrease in CMC. The mixed system is a non-ideal mixed system, which is consistent with the kinetic mechanism of mixing and diffusion. The hybrid system has good aggregation pattern and wetting diffusion behavior and has low foam stability due to slow maturation of Ostwald.

Application of reactive fatty alcohol ether sulfosuccinate emulsifier in surface sizing

AbstractIn this paper, a novel reactive fatty alcohol ether sulfosuccinate emulsifier (RAEOSS10‐9) was polymerized into macromolecular emulsifier RAFT‐PRS through reversible addition–fragmentation chain transfer (RAFT) polymerization, and then RAFT‐PRS was co‐polymerized with monomers to form anionic surface sizing agent. The structures of RAEOSS10‐9 and RAFT‐PRS were characterized by Fourier transfer infrared spectra, and the RAFT polymerization activity of RAFT‐PRS was verified by gel permeation chromatography. The effects of RAFT reagent and RAEOSS10‐9 content on the properties of sizing emulsion and sizing paper were investigated. The morphology of latex particles and sizing paper surface were observed by use of scanning electron microscope and atomic force microscope. The water resistance, bursting resistance and folding resistance of sizing paper were studied. The optimal formulation of sizing emulsion was built according to the above results. Besides, the investigation of the mechanical properties suggests that proper amount of reactive emulsifier is beneficial for enhancing the stability of emulsion and the performance of paper. The RAEOSS10‐9 displays better emulsifying properties than imported emulsifier SR‐10, and the emulsion produced by RAEOSS10‐9 display more excellent application properties.

Adsorption, Aggregation, and Application Properties of Green Pluronic Aliphatic Alcohol Ether Carboxylic Acids and Nonionic/Amphoteric Surfactants in Water.

In the realm of colloid and interface science, new types of green surfactants, including anionic Pluronic alcohol ether carboxylate (AEC), branched alkyl glucoside (IG), and zwitterionic coconut oil amide propyl betaine (CAB), have been identified and merit further exploration. AEC, characterized by its inclusion of 5 EO and 3.5 PO units, was synthesized, and its behavior in aqueous solutions with IG and CAB was meticulously examined. Their performance in applications such as foam generation, wetting, and the dispersion and stabilization of graphene was also evaluated. At αAE5P3C = 0.5, AE5P3C/CAB exhibited superior surface and interfacial properties compared to AE5P3C/IG. In these hybrid systems, the self-assembly of micelles is predominantly influenced by hydrogen bonding, electrostatic interactions, and hydrophobic forces. Kinetic analysis further confirmed that the driving force for micelle formation in these hybrid systems is enthalpy, with the adsorption process involving a mixed diffusion-kinetic adsorption mechanism. AE5P3C/CAB demonstrated enhanced foaming ability, foam stability, and wetting properties compared to AE5P3C/IG. Intriguingly, the optimal dispersion and stabilization of graphene were achieved with AE5P3C/IG at αAE5P3C = 0.2, providing a foundational basis for its potential application in graphene-based systems. A thorough examination of the synergistic mechanisms and application potential of these three distinct surfactants in aqueous solutions was presented, taking into account various charged ions and the specific hydrophilic and hydrophobic groups of EO and PO. This study not only provides fundamental insights into their intrinsic properties but also offers a fresh perspective for the ongoing exploration of green surfactants.

Efficient separation of diisopropyl ether and ethanol using green solvents: Thermodynamic analysis and process simulation

Ionic liquids (ILs) and deep eutectic solvents (DESs) were first proposed as green solvents to study and compare their azeotropic separation effects in diisopropyl ether (DIPE) and ethanol (EA). The COSMO-RS model was used to screen ILs/DESs, and the feasibility of the extractants were comprehensively analyzed in terms of viscosity, thermal stability, and toxicity. Experiments were carried out on selected ILs and DESs, and the results showed that the separation effect of ILs was significantly stronger than that of DESs. Quantum chemical calculations and molecular dynamics simulations were combined to comprehensively analyze and compare the microscopic mechanisms of extraction separation. Based on the experimental data, a DIPE-EA extraction-coupled separation process was designed. For the first time, life cycle analysis was used to comprehensively evaluate the impact of this process on human health and the environment from multiple perspectives, providing theoretical guidance for the separation of alcohol ethers in the industry.

Trace alcohol ether electrolytes with dual-site hydrogen bonds and modulated solvation structures for ultralong-life zinc-ion batteries

Aqueous zinc-ion batteries (AZIBs) are highly regarded for their affordability, stability, safety, and eco-friendliness. Nevertheless, their practical application is hindered by severe side reactions and the formation of zinc (Zn) dendrites on the Zn metal anode surface. In this study, we employ tetrahydrofuran alcohol (THFA), an efficient and cost-effective alcohol ether electrolyte, to mitigate these issues and achieve ultralong-life AZIBs. Theoretical calculations and experimental findings demonstrate that THFA acts as both a hydrogen bonding donor and acceptor, effectively anchoring H2O molecules through dual-site hydrogen bonding. This mechanism restricts the activity of free water molecules. Moreover, the two oxygen (O) atoms in THFA serve as dual solvation sites, enhancing the desolvation kinetics of [Zn(H2O)6]2+ and improving the deposition dynamics of Zn2+ ions. As a result, even trace amounts of THFA significantly suppress adverse reactions and the formation of Zn dendrites, enabling highly reversible Zn metal anodes for ultralong-life AZIBs. Specifically, a Zn-based symmetric cell containing 2 % THFA achieves an ultralong cycle life of 8,800 h at 0.5 mA cm−2/0.5 mAh cm−2, while a Zn//VO2 full cell containing 2 % THFA maintains a remarkable 80.03 % capacity retention rate at 5 A g−1 over 2,000 cycles. This study presents a practical strategy to develop dendrite-free, cost-effective, and highly efficient aqueous energy storage systems by leveraging alcohol ether compounds with dual-site hydrogen bonding capabilities.

Catalytic dehydrative cross-coupling of alcohols: An eco-friendly approach to unsymmetrical ethers

Developing green as well as sustainable protocols by employing cheap and readily available catalysts and/or reagents without using environmentally hazardous solvents is becoming more significant to the researcher community. Here, we introduce a green and metal-free catalytic method for the etherification of alcohols by using catalytic NH4I and oxone under mild conditions. The reagents we employed are inexpensive, abundant in nature, readily available, easy to handle and produce non-polluting by-products, which can be easily removable by simple aqueous work-up. This makes our approach more convenient, sustainable and economically viable. The present catalytic system does not require any organic solvent as reaction medium to facilitate the reaction. Using this green approach, we have synthesized a wide range of unsymmetrical ethers from two distinct types of alcohols (secondary benzylic and primary (benzylic or non-benzylic) alcohols) which demonstrated the efficiency of our protocol. Further, the gram scale reactions established the feasibility in scaling-up of our process.

Investigation of CO2 capture performance of polyamine/organic alcohol ether non-aqueous absorbent regulated by ethylene glycol

The use of non-aqueous absorbents has great potential in reducing energy consumption during CO2 capture. However, current obstacles include the formation of precipitation or gelatinous substances after CO2 absorption, which significantly hinder their further application. Moreover, it is crucial to address concerns about insufficient CO2 capture performance and excessive regeneration energy. Therefore, non-aqueous homogeneous absorbents that do not produce precipitates, gels, or solids have gained considerable attention in recent years. In this study, a novel non-aqueous homogeneous absorbent based on polyamine/complex solvent was successfully developed by introducing ethylene glycol into the precipitation-producing polyamine/organic alcohol ether system. This modification resulted in improved CO2 capture performance and reduced regeneration energy. The AEEA/EG/2EE non-aqueous homogeneous absorbent showed a CO2 absorption capacity of 2.67 mol/kg and achieved an impressive regeneration efficiency of up to 81.65 % at the optimal desorption temperature (393 K) in only 40 min, surpassing the conventional MEA/H2O absorbent by a substantial margin (31.65 %). Thermodynamic analysis revealed that this absorbent exhibited a substantial reduction in both sensible and latent heat during CO2 desorption, resulting in a remarkable decrease of 42.8 % in total regeneration energy compared to the conventional MEA/H2O absorbent. The composite solvent EG/2EE was found not to be involved in the reaction process according to the 13C NMR analysis. The main absorption process involved the reaction between organic amine AEEA and CO2 to form carbamate, while the desorption process entailed reverse decomposition of carbamate for CO2 release. Therefore, utilizing ethylene glycol's advantageous properties for regulating polyamine/organic solvent systems presents a promising.

Organophotocatalyzed C‐Si Bond Fragmentation Using Silyl Ethers as Radical Precursors

In this work, silyl ethers of phenols and alcohols have been successfully prepared and tested as neutral carbon (silicon) centered radical precursors. The organocophotocatalyzed oxidation (by the Fukuzumi catalyst) of these ethers caused the cleavage of a C‐Si (or a Si‐Si) bond for the release of the desired radical to be used for the forging of C(sp3)‐C(sp3) (or C(sp3)‐Si) bonds via a Giese reaction.

Densities, Viscosities, and Self-Diffusion Coefficients of Octan-1-ol and Related Ether-Alcohols.

Density, viscosity, and self-diffusion coefficients are reported for octan-1-ol and the related ether-alcohols 2-pentoxy-ethan-1-ol, 3-butoxypropan-1-ol, 4-propoxybutan-1-ol, 5-ethoxypentan-1-ol, and 6-methoxyhexan-1-ol covering temperature ranges from 298.15 to 359.15 K. These new data reveal structure-property relationships affected by the presence and the position of the ether moiety in the molecular structure of the ether-alcohols. Compared to octan-1-ol, the presence of the ether moiety causes an increase in intermolecular hydrogen bonding interactions, resulting in higher densities. The increase in density is less pronounced for those ether-octanols that engage in intramolecular hydrogen bonding. As for the effects of the ether moiety on the dynamics, these are generally faster for the ether-alcohols compared to octan-1-ol, suggesting that hydrogen bonding between ether oxygen and hydroxy hydrogen is weaker compared to hydrogen bonding between two hydroxy groups. The activation energies obtained from an Arrhenius analysis are higher for translational motion than for momentum transfer for all alcohols. There are additional finer details across the ether alcohols for these activation barriers. These differences cancel out for the mathematical product of self-diffusion coefficient and viscosity (Dη). The effect of water impurities on the studied properties was also investigated and found to lead to small increases in densities for all alcohols. Viscosities decrease for octan-1-ol and 2-pentoxyethan-1-ol but increase for the other ether-alcohols that can engage in intramolecular hydrogen bonding.

Study on dynamic characteristics of anionic surfactants containing ethoxy groups wetting bituminous coal

Coal dust restricts coal mine safety and green production. Wet dust removal is widely used in coal mining, processing and transportation. High-efficiency dust suppressants help control coal dust and improve the working environment. The wetting behaviors of dust suppression droplets on coal affect the dust reduction efficiency. In order to select high-quality and efficient water-based materials, four ethoxy-containing surfactants with similar structures, fatty alcohol ether sulfate (AES), lauryl alcohol sulfosuccinate disodium (MES), fatty acid methyl ester ethoxylates (FMEE) and fatty acid methyl esters ethoxylate sodium sulfonate (FMES), are selected to prepare solutions with different concentrations. Through the droplet impact wetting experimental system, the dimensionless spreading coefficient of droplets is compared. The results show that the spreading behavior of the four surfactant-containing droplets is better than that of distilled water droplets, and the maximum dimensionless spreading coefficient follows the rule of AES > MES > FMES > FMEE >distilled water. The maximum dimensionless spreading coefficient of the droplet first increases sharply with the increase of the concentration, and then increases slowly when the concentration reaches the critical micelle concentration (CMC). The adsorption configuration of water-surfactant-coal system is simulated by molecular dynamics (MD) simulation. The relative concentration distribution of each component and the mean square displacement (MSD) of water molecules are analyzed. The interaction energy of the system is calculated. The simulation results verified the effectiveness of the impact wetting experiment results.

Impact of anionic surfactant-based foaming agents on the properties of lightweight foamed concrete

Due to its low density, high thermal insulation, and ability to contribute to energy saving, lightweight foamed concrete (LWFC) is a versatile material that finds use in a wide variety of contexts. The properties of foam are significantly influenced by the selection of surfactant and foam production parameters, which in turn impact the properties of LWFC. Therefore, the anionic foaming agent effect on the distinct properties of LWFC needs to be investigated to create a lightweight structure in modern days. This research aims to better understand the interactions between cement particles and anionic foaming agents, which produce stable and consistent aqueous foams because of their negative charge. Investigations were carried out on the effects of anionic foaming agents of LWFC features on the fresh state characteristics, mechanical behaviour, microstructure, and transport properties. In this investigation, four distinct types of anionic surfactants specifically sodium lauryl sulphate (SLS), alpha olefin sulfonate (AOS), sodium lauryl ether sulphate (SLES), and sodium alcohol ether sulphate (AES) were considered, with all mixes maintaining a consistent cement-to-sand ratio and identical amounts of foaming agents. The fresh state testing exhibits that AOS-based LWFC may be preferred when lower setting time and spreadability, as well as a higher density, are required. The AOS-based LWFC exhibits lower capillary sorption, water absorption, and gas permeability than SLES, SLS, and AES-based LWFC. At 28 days, about 91–96 % of the compressive, tensile, and flexural strength of AOS-based LWFC is obtained for SLS, SLES, and AES-based LWFC. In addition, at the same curing age, the results for modulus of elasticity were over 6 % higher in the AOS-based LWFC mixture than in the other mixes. The pore structural and microstructural behavior revealed that AOS and SLS foamed-based LWFC exhibit a considerable reduction of macropores, or long capillaries, with diameters less than 500 µm, which can be used in the lightweight structure in modern days. This research emphasizes the significance of selecting the appropriate foaming agents to optimize the mechanical and transport properties of LWFC, which provides substantial benefits for contemporary construction practices.

Esterification and Etherification of Aliphatic Alcohols Enabled by Catalytic Strain-Release of Donor-Acceptor Cyclopropane.

We herein disclose a highly efficient protocol for the esterification and etherification of alcohols, leveraging a Sc(OTf)3-catalyzed ring-strain release event in the meticulously designed, chromatographically stable mixed anhydrides or benzyl esters that incorporate an intramolecular donor-acceptor cyclopropane (DAC). This versatile method facilitates the straightforward functionalization of sugar, terpene, and steroid alcohols under mild acidic conditions, as showcased by the single-catalyst-driven, dual protection of sugar diol.

Unveiling the dissolution behavior of letrozole in fourteen pure solvents: Insights from experiments and molecular simulations

The dissolution behavior of an active pharmaceutical ingredient (API) in different solvents is of great importance for the design and optimization of its crystallization process. In this study, the solubility of letrozole in fourteen pure solvents was determined using a gravimetric method within the temperature range of 283.15–323.15 K at atmospheric pressure. The results demonstrate a significant correlation between letrozole’s dissolution behavior and the molecular structure (carbon chain length and presence of branched chains) and properties (dielectric constant and cohesive energy density) of the solvent. Solubility analysis and simple crystallization experiments suggest that acetonitrile may serve as a suitable solvent for the cooling crystallization of letrozole. To enhance the applicability of solubility data, five mathematical models were employed for data fitting. In addition, the Van’t Hoff equation was utilized to calculate the apparent thermodynamic properties of the letrozole dissolution process. Furthermore, molecular simulations were conducted to investigate the dissolution behavior of letrozole in different solvents, revealing distinct patterns of interaction between solute and solvent molecules. Specifically, in alcohol solvents, alcohol ether solvents, and acetonitrile, solute molecules interact with solvent molecules primarily as hydrogen bond acceptors, whereas the opposite behavior is observed in ester solvents and acetone. Binding energy, radial distribution function (RDF), and coordination number (CN) analyses effectively elucidate the dissolution behavior of letrozole in solvents of the same category, indicating that stronger solute–solvent interactions result in higher solubility. A comprehensive examination of solute–solvent and solvent–solvent interactions offers a rational explanation for letrozole’s dissolution behavior in solvents of different categories, highlighting the decisive impact of solvent–solvent interactions, particularly in alcohol solvents and acetone.

Adsorption behavior and application properties of natural alcohol polyoxyethylene polyoxypropylene ether sulfate

In recent years, the Polyoxypropylene (PO) group has been introduced between the hydrophobic group and the polyoxyethylene (EO) group of traditional surfactants to enhance interfacial properties. However, literature on surfactants introducing PO chains between EO and hydrophilic groups remains scarce. In this study, three variants of natural alcohol polyoxyethylene polyoxypropylene ether sulfate (C1214E3PnS), each with different PO addition numbers, were synthesized from natural alcohol ether through sulfation and neutralization reactions. The adsorption behavior of C1214E3PnS with different PO addition numbers was investigated and compared to AES by measuring surface tension, dynamic surface tension, and contact angle. The results indicate that as the number of PO increases, both the critical micelle concentration and maximum adsorption capacity decrease. Additionally, pC20 and the number of PO groups introduced in the surfactant show a linear negative correlation, indicating a decline in surfactant efficiency. Due to an adsorption barrier, C1214E3PnS is governed by a mixed diffusion-kinetics adsorption mechanism. According to the application performance of C1214E3PnS, as the number of PO increases, wettability and foam stability have decline, while emulsifying performance is significantly enhanced. In conclusion, surfactants such as C1214E3PnS do not favor adsorption at the solid–liquid interface, but enhance the properties at the oil–water interface.

Synthesis of ZSM-5 Zeolite Nanosheets with Tunable Silanol Nest Contents across an Ultra-wide pH Range and Their Catalytic Validation.

Zeolite synthesis under acidic conditions has always presented a challenge. In this study, we successfully prepared series of ZSM-5 zeolite nanosheets (Z-5-SCA-X) over a broad pH range (4 to 13) without the need for additional supplements. This achievement was realized through aggregation crystallization of ZSM-5 zeolite subcrystal (Z-5-SC) with highly short-range ordering and ultrasmall size extracted from the synthetic system of ZSM-5 zeolite. Furthermore, the crystallization behavior of Z-5-SC was investigated, revealing its non-classical crystallization process under mildly alkaline and acidic conditions (pH<10), and the combination of classical and non-classical processes under strongly alkaline conditions (pH≥10). What's particularly intriguing is that, the silanol nest content in the resultant Z-5-SCA-X samples appears to be dependent on the pH values during the Z-5-SC crystallization process rather than its crystallinity. Finally, the results of the furfuryl alcohol etherification reaction demonstrate that reducing the concentration of silanol nests significantly enhances the catalytic performance of the Z-5-SCA-X zeolite. The ability to synthesize zeolite in neutral and acidic environments without the additional mineralizing agents not only broadens the current view of traditional zeolite synthesis but also provides a new approach to control the silanol nest content of zeolite catalysts.

Synthesis of ZSM‐5 Zeolite Nanosheets with Tunable Silanol Nest Contents across an Ultra‐wide pH Range and Their Catalytic Validation

AbstractZeolite synthesis under acidic conditions has always presented a challenge. In this study, we successfully prepared series of ZSM‐5 zeolite nanosheets (Z‐5‐SCA‐X) over a broad pH range (4 to 13) without the need for additional supplements. This achievement was realized through aggregation crystallization of ZSM‐5 zeolite subcrystal (Z‐5‐SC) with highly short‐range ordering and ultrasmall size extracted from the synthetic system of ZSM‐5 zeolite. Furthermore, the crystallization behavior of Z‐5‐SC was investigated, revealing its non‐classical crystallization process under mildly alkaline and acidic conditions (pH&lt;10), and the combination of classical and non‐classical processes under strongly alkaline conditions (pH≥10). What's particularly intriguing is that, the silanol nest content in the resultant Z‐5‐SCA‐X samples appears to be dependent on the pH values during the Z‐5‐SC crystallization process rather than its crystallinity. Finally, the results of the furfuryl alcohol etherification reaction demonstrate that reducing the concentration of silanol nests significantly enhances the catalytic performance of the Z‐5‐SCA‐X zeolite. The ability to synthesize zeolite in neutral and acidic environments without the additional mineralizing agents not only broadens the current view of traditional zeolite synthesis but also provides a new approach to control the silanol nest content of zeolite catalysts.