Cyclohexanol Research Articles

Needle growth of Nb2O5 nanoparticles on BiOCl nanosheets to fabricate S-scheme heterojunction with oxygen vacancies for enhanced photooxidation of cyclohexane

The exploration of cost-efficient, environmentally friendly, and high-efficacy photocatalysts for the enhanced selective photooxidation of cyclohexane to KA oil (cyclohexanone (CHA-one) and cyclohexanol (CHA-ol)) is a pivotal challenge in the industrial realm. Herein, the present study focuses on the synthesis of needle-like S-scheme heterojunction photocatalysts with oxygen vacancies, which are achieved by the needle growth integration of nano-sized Nb2O5 particles onto the BiOCl nanosheets. Remarkably, the 40 % Nb2O5/BiOCl composites exhibited superior performance in the solvent-free photooxidation of cyclohexane at room-temperature and under atmospheric pressure. The production yield of KA oil was 180.3 μmol (CHA-one/CHA-ol molar ratio = 3.5), and exceptional selectivity towards KA oil, reaching up to 99.3 %. The enhanced photocatalytic efficiency in cyclohexane oxidation can be attributed to the unique S-scheme heterogeneous interfaces with specific nanoneedle morphology, which result in the enhanced photonic absorption, effective charge carrier separation, a high density of oxygen vacancies, and the exposure of the highly reactive (001) plane of BiOCl. The excellent interfacial charge separation and transfer pathways of S-scheme heterojunction are disclosed by the in-depth EPR analysis and DFT calculations. These insights highlight the significant potential of the needle-like Bi-based S-scheme heterojunction photocatalysts for the efficient photooxidation of saturated alkanes.

Tailored MgAl2O4 supported Ru catalyst for selective C–O bond cleavage in diphenyl ether hydrogenolysis

The direct cleavage of C−O bonds in lignin and its derivatives via hydrogenolysis is an essential reaction process for lignin conversion. Herein, we design a MgAl2O4 supported Ru catalyst using a facile and green method involving ball milling and microwave heating. The optimal catalyst, 0.5Ru/MgAl2O4, displayed enhanced catalytic performance for 4−O−5 linkage scission compared to 0.5Ru/Al2O3 and 0.5Ru/MgO, achieving a tuenover frequency of 352.9 h−1 for diphenyl ether (DPE) conversion. 0.5Ru/MgAl2O4 with low Ru loading achieved complete conversion of DPE, with 43.8% yield of cyclohexane (CHE) and 42.6% yield of cyclohexanol (CHL) after 2 h at 160 °C and 1.5 MPa H2. The promising catalytic activity can be attributed to the abundant electron-rich Ru0 species with high dispersion formed on MgAl2O4, derived from the strong electron transfer from the support to Ru. The reaction mechanism for the direct cleavage of the 4−O−5 bond, followed by phenyl ring hydrogenation, was confirmed by rigorous experiments. This work provides an inspiring idea for developing efficient heterogeneous catalysts for the utilization of lignin resources via hydrogenolysis.

Lignin-incorporated Co-MOFs-derived catalysts for selective hydrodeoxygenation of lignin-derived phenols into cyclohexanols

Lignin accounted for the second largest amount in biomass, and was regarded as an important carbon source and important renewable source for value-added chemicals. Herein, a series of lignin-derived carbon-based heterogeneous catalyst was synthesized through a simple hydrothermal method, using Co-MOFs as template. Lignin was introduced as a carbon material into MOF catalysts. Through some characterizations, it has been proven that lignin has been successfully introduced into MOF materials and significantly improved the catalyst performance. Then, lignin-MOF derived catalysts (Co/C-EL-X) were successfully introduced into the catalytic hydrodeoxygenation of lignin-derived phenols. The addition of enzymatic hydrolysis lignin (EL) in catalysts, calcination temperature and some other factors were investigated in detail, considering the catalytic performance during the HDO of vanillin and other typical lignin-derived phenols. Co/C-EL-0.5(500) exhibited the best catalytic performance for the conversion of different kinds of lignin-derived phenols to either 2-methoxy-4-methylphenol (MMP) or cyclohexanol. Under the optimal conditions of 240 °C, 0 MPa N2, and 2 h, the conversion rate of vanillin reached 100 %, and the yield of 4-methyl-2-methoxyphenol (MMP) was up to 92 %. Furthermore, vanillin could also be converted into 4-methylcyclohexanol (MCYL) by changing the initial nitrogen pressure. Also, Co/C-EL-0.5 (500) exhibited high activity for the conversion of other lignin-derived phenols into cyclohexanol (COL). This work provided a novel strategy for the catalytic valorization of lignin sources.

In situ activated CoAg bimetallic catalyst for selective hydrodeoxygenation of syringol to cyclohexanol

Development of highly effective catalysts for selective hydrodeoxygenation (HDO) of syringol, a model compound of lignin, to cyclohexanol (CYHAOL) is a challenge due to the intricate molecular structure of syringol. Herein, we have synthesized an in–situ activated cobalt–silver bimetallic catalyst, CoAg/SiO2, through a simple incipient–wetness impregnation method. The catalyst without pre–reduction treatment attained a complete conversion with 93.8 mol% CYHAOL selectivity under moderate reaction conditions. Characterizations including HRTEM, XPS, XRD, NH3–TPD, and H2–TPR unanimously revealed the structure–activity relationship of the catalyst. In the reaction system, Ag promoted the in–situ reduction of Co3O4 to form a polycrystalline–structure complex (CoOx) containing oxygen vacancies. Ag also combines with Co to construct strong acid sites. The synergy of CoOx, oxygen vacancies, Ag, and acid sites demonstrates a high–efficiency HDO of syringol to CYHAOL. CoAg/SiO2 exonerates the pre–reduction treatment, simplifying the preparation and maintenance process and preventing severe sintering of the metals.

Separation of cyclohexanol from cyclohexanol/cyclohexene mixtures by crystals of pillar[6]arene containing three benzoquinone units.

Here, we develop a new absorbent for efficient separation of cyclohexanol (CHA-ol) and cyclohexene (CHA-ene) by using crystals of pillar[6]arene with three benzoquinone units (P3QA). P3QA crystals are found to show remarkable selectivity for CHA-ol in 50 : 50 (v/v) CHA-ol : CHA-ene mixtures with a purity of 95.2%, along with vapochromic behavior.

Directional Electrosynthesis of Adipic Acid and Cyclohexanone by Controlling the Active Sites on NiOOH.

Dicarboxylic acids and cyclic ketones, such as adipic acid (AA) and cyclohexanone (CHN), are essential compounds for the chemical industry. Although their production by electrosynthesis using electricity is considered one of the most promising strategies, the application of such processes has been hampered by a lack of efficient catalysts as well as a lack of understanding of the mechanism. Herein, a series of monolithic msig/ea-NiOOH-Ni(OH)2/NF were prepared by means of self-dissolution of metal matrix components, interface growth, and electrochemical activation (denoted as msig/ea). The as-synthesized catalysts have three-dimensional cuboid-like structures formed by interconnecting nanosheets composed of NiOOH. By theoretically guided regulation of the amounts of Ni3+ and oxygen vacancies (OV), a 96.5% yield of CHN from cyclohexanol (CHA) dehydrogenation and a 93.6% yield of AA from CHN oxidation were achieved. A combined experimental and theoretical study demonstrates that CHA dehydrogenation and CHN oxidation were promoted by the formation of Ni3+ and the peroxide species (*OOH) on OV. This work provides a promising approach for directional electrosynthesis of high-purity chemicals with in-depth mechanistic insights.

Modification of crystal growth of NaA zeolite with steric hindrance agents for removing ammonium ion from aqueous solution

The incorporation of steric effects into the hydrothermal synthesis system of NaA zeolite proves to be an effective method for modifying grain size, enhancing grain dispersion and obtaining single crystal products. In this study, three different molecular configurations, namely short-chain ethanolamine (MEA), long-chain polyethylene glycol (PEG), and ring-chain cyclohexanol (CyOH), were employed to investigate the impact of steric effects on the crystal growth of NaA zeolite. The crystal form, morphology, and particle size of NaA zeolite were characterized using XRD, FT-IR, and SEM techniques. The order of steric hindrance in terms of molecular configuration was found to be as follows: CyOH > PEG > MEA. NaA-CyOH exhibited a high dispersion of single crystal particles, the smallest grain size, and the largest specific surface area and pore volume. To evaluate the ammonium ion adsorption performance, NaA-CyOH-31, the zeolite with the best performance, was utilized for studying the reaction kinetics. The results indicated that the adsorption behavior of NaA zeolite towards ammonium ion could be better described by the quasi second-order equation and the Langmuir model. Furthermore, the evaluation of the regeneration ability of NaA-CyOH zeolite demonstrated that the recovered adsorbent still maintained a high level of adsorption performance.

Study of Co-operative Dynamics in Cyclohexanol-Xylene Solutions using Dielectric Relaxation Spectroscopy

Cooperative dynamics in pure cyclohexanol (CYN), xylene and their binary solutions have been studied using dielectric relaxation spectroscopy (DRS) in 10 MHz to 30 GHz microwave frequency range. The dynamics in CYN-CYN, CYN-xylene molecules have been explained using concept of cooperative domains (CDs). Deviations in CYN-xylene binary solutions exist due to braking and making of bonds as well as selfassociation among the molecules. Kirkwood correlation factor authenticates CDs with diverse exchanges through hydrogen bonding. Luzar model offers moderately decent qualitative values of εo such that the theoretically calculated values found relatively good in comparison with experimental results.

Separation of Cyclohexanone and Cyclohexanol by Adaptive Pillar[5]arene Cocrystals Accompanied by Vapochromic Behavior.

The separation of cyclohexanone (CHA-one) and cyclohexanol (CHA-ol) mixtures is of great importance in the chemical industry. Current technology exploits multiple steps of energy-intensive rectification due to their close boiling points. Herein, we report a new and energy-efficient adsorptive separation method employing binary adaptive macrocycle cocrystals (MCCs) built with π-electron-rich pillar[5]arene (P5) and an electron-deficient naphthalenediimide derivative (NDI) that can selectively separate CHA-one from an equimolar CHA-one/CHA-ol mixture with >99% purity. Intriguingly, this adsorptive separation process is accompanied by vapochromic behavior from pink to dark brown. Single-crystal and powder X-ray diffraction analyses reveal that the adsorptive selectivity and vapochromic property are derived from the CHA-one vapor inside the cocrystal lattice voids triggering solid-state structural transformations to yield charge-transfer (CT) cocrystals. Moreover, the reversible transformations make the cocrystalline materials highly recyclable.

Selective catalytic hydroconversion of crude phenols to cyclohexanols over a carbon-based nickel catalyst and separation of condensed arenes from a low-temperature coal tar

The dynamic combined strategy consisting of extraction, column chromatography, and catalytic hydroconversion (CHC) was used to prepare cyclohexanol (CH) from crude phenols (CPs) derived from a low temperature coal tar (LTCT) and enrich condensed arenes from the dephenolized fraction. Fluoranthene, anthracene, and pyrene with purities of 92.2, 91.7, and 95.5 %, respectively, were enriched by a combination of extraction and gradient elution in medium pressure preparative liquid chromatograph (MPPLCI) and high pressure preparative liquid chromatograph. CPs obtained by extracting LTCT were catalytically hydroconverted over a nickel supported on a nitrogen-doped carbon material (NDCM) prepared with a nickel-organic framework as the precursor. The mechanism for the CHC of CPs was explored using phenol as the model compound. The results show that phenol was completely converted and the selectivity of CH is up to 99.9 % in n-hexane under initial hydrogen pressure of 3 MPa at 160 °C for 1 h. The characterization of Ni/NDCM and the distribution of the products from the CHC of phenol indicate that Ni/NDCM can strongly adsorb phenol and effectively activate H2 to H···H, which transfer plays a crucial role in hydrogenating the aromatic rings.

Highly efficient solvent-free oxidation of cyclohexanol to cyclohexanone over nanocrystalline CaO–MgO binary metal-oxide catalysts

The development of inexpensive solid-base CaO–MgO binary metal oxides (BMOs) as efficient and reusable heterogeneous catalysts was reported for the selective production of cyclohexanone (CyONE) from cyclohexanol (CyOH) oxidation under solvent-free conditions. These BMOs were prepared by ultra–diluted co-precipitation procedure and characterized by several sophisticated techniques, such as XRD, BET, CO2–TPD, FTIR, SEM, EDX, TEM, and ICP-OES. The crystallinity of the BMO samples was found from the XRD analysis and the estimated crystalline size range of the samples is 19.02–23.42 nm. The BET and CO2–TPD analysis of prepared samples gave information regarding the specific surface area and basicity (concentration and strength). The morphology and particle size of the 1CaO–1.5MgO sample were obtained from the SEM (61.8 nm) and TEM (55.2 nm) analyzes. Among all the catalysts, the 1CaO–1.5MgO catalyst displayed a higher conversion of CyOH (∼85%) with superior selectivity to CyONE product (∼90.97). The greater catalytic efficiency of the 1CaO–1.5MgO catalyst was attributed to the greater specific surface area, the smaller particle size of the MgO, the optimized composition of CaO–MgO (1:1.5), and higher basic strength along with a large number of basic sites. We have also optimized various reaction parameters including reaction temperature, time, catalyst weight, and solvent. Catalyst recyclability experiments were carried out to disclose that the catalyst has more robust, stable, and easily recyclable. The 1CaO–1.5MgO catalyst was very stable up to the 4th cycle. We also studied the spent catalyst characterization (XRD, BET, FTIR, SEM, TEM, and ICP-OES) to know the fundamental reason for the deactivation of the CM-4 catalyst.

Selective catalytic hydroconversion of a low-temperature coal tar-derived crude phenols to cyclohexanol over a nitrogen-doped Co-based catalyst

An extraction-catalytic hydroconversion (CHC)-column chromatography strategy was designed for the CHC of crude phenols to obtain cyclohexanol (CH) and enrich non-substituted condensed arenes (NSCAs) from a low-temperature coal tar (LTCT). Phenanthrene, fluoranthene, and pyrene were enriched with purities of 94.3%, 90.1%, and 96.1%, respectively, by extraction with petroleum ether and methanol and subsequent gradient elution using a medium pressure preparative liquid chromatograph (MPPLC) and high pressure preparative liquid chromatograph. Co supported on a nitrogen-doped carbon material (NDCM) was prepared by one-step pyrolysis of a cobalt-organic framework under N2 atmosphere and crude phenols (CPs) were extracted from the LTCT. CH with a purity of 98.7% was obtained by catalytically hydroconverting CPs over Co/NDCM and subsequent elution using the MPPLC. The mechanism for the CHC of CPs over Co/NDCM was examined using phenol as the LTCT-related model compound. As a result, phenol was completely converted and the CH selectivity reached 97.7% in n-hexane under initial hydrogen pressure of 3 MPa at 140 °C for 3 h. The characterization of Co/NDCM and the distribution of products from the CHC of phenol indicate that Co/NDCM can activate H2 to H···H and the H···H transfer plays a crucial role in hydrogenating aromatic rings.

Experimental and DFT investigation on the role of aromaticity on the stability of hydrogen bonded complexes of cyclohexanone with amines and hydroxyl compounds

The existence of intermolecular hydrogen bonded interaction between four structurally hydroxyl and amino compounds namely, phenol (PHE), aniline (ANI), cyclohexanol (CHL) and cyclohexylamine (CHA) with cyclohexanone (CHE) was investigated in n-hexane medium at 303 K by experimental methods (ultrasonic, UV–Visible, IR spectral analysis) and theoretical (DFT, NCI) methods. From the acoustical and excess thermo-acoustical parameters, strong solute–solute interactions of hydrogen bonded type between the solutes were established. The formation of 1:1complexes between cyclohexanone and hydroxyl, amino compounds was confirmed by UV–visible spectral method and the presence of hydrogen bonding in these complexes was proved by IR spectrum. The stability constant of the four hydrogen bonded complexes was calculated by both ultrasonic and UV–Visible spectroscopic methods. Interestingly, it was found that the order of strength of hydrogen bonding between CHE and hydroxyl as well as amino compounds is in the order CHE-PHE > CHE-ANI > CHE-CHL > CHE-CHA. DFT calculations, NBO analysis and NCI plots were also made to quantify the nature of stabilizing interactions between CHE and hydroxyl and amino compounds. Our computed results are in good agreement with the experimental observations. It is observed that aromatic moiety adjacent to hydrogen donor influences significantly the stability of the H-bonded complexes.

Alkane Oxidation with H2O2 Catalyzed by Dicopper Complex with 6-hpa Ligand: Mechanistic Insights as Key Features for Methane Oxidation

Abstract Alkane oxidations with H2O2 catalyzed by copper complexes [Cu2(µ-OH)(6-hpa)]3+ (1) and [Cu(MeCN)(tpa)]2+ (2) were examined. In the oxidation of cyclohexane (CyH), cyclohexyl hydroperoxide (CyO2H) was formed as the first product and converted to cyclohexanol (CyOH) with PPh3. The turnover frequency (TOF/h) and turnover number (TON) of 1 are 150 and 1030, respectively. The kinetic studies showed that the product formation rate, d[CyO2H]/dt, is proportional to [1] and [H2O2], and partly to [Et3N] and [H2O]. Solvent kinetic isotope effect kH2O/kD2O was 2.2, showing that a H2O molecule is involved in the rate-limiting step. tert-BuO2H disturbs the formation of a di(hydroperoxo) intermediate [Cu2(O2H)2(6-hpa)]2+ to reduce the d[CyO2H]/dt. The active species [Cu2(O•)(O2•)(6-hpa)]2+ was detected by CSI MS. The inhibitory effects of a radical trap reagent DMPO and CO gas revealed that 1 suppresses the HO• formation. Methane oxidation with H2O2 catalyzed by 1, 2, and related complexes was conducted using a high-pressure reactor. Key features for the high catalytic activity of 1 in the methane oxidation are the complex-based active species [Cu2(O•)(O2•)(6-hpa)]2+ capable of cleaving the strong C-H bond of methane and the long catalyst life enabled by the suppression of the HO• formation.

Aromaticity effect on supramolecular aggregation. Aromatic vs. cyclic monohydroxy alcohols

In this paper, the steric hindrance effect related to the presence of either a cyclic or aromatic ring on the self-association process in the series of monohydroxy alcohols (MAs), from cyclohexanemethanol to 4-cyclohexyl-1-butanol and from benzyl alcohol to 4-phenyl-1-butanol, was studied using X-Ray Diffraction (XRD), Differential Scanning Calorimetry (DSC), Fourier Transform Infrared (FTIR) spectroscopy, Broadband Dielectric Spectroscopy (BDS) and the Pendant Drop (PD) methods. Based on FTIR results, it was shown that phenyl alcohol (PhA) and cyclohexyl alcohol (CA) derivatives reveal substantial differences in the association degree, the activation energy of dissociation, and the homogeneity of supramolecular nanoassociates suggesting that the phenyl ring exerts a stronger steric impact on the self-assembling of molecules than cyclohexyl one. Additionally, XRD data revealed that phenyl moiety introduces more heterogeneity in the organization of molecules compared to the cyclic one. The changes in the self-association process of alcohols were also reflected in differences in the molecular dynamics of the H-bonded aggregates, as well as in the Kirkwood factor, defining the long-range correlation between dipoles, which were slightly higher for CAs with respect to those determined for PhAs. Unexpectedly it was also found that the surface layers of PhAs were more organized than those formed by CAs. Thus, these findings provided insight into the impact of aromaticity on the self–assembly process, H-bonding pattern, supramolecular structure, and intermolecular dynamics of the studied alcohols.

Thermodynamic and Dielectric Properties of Cyclohexanol-Xylene Binary Mixtures Using Dielectric Spectroscopy

The complex permittivity spectra for cyclohexanol (CYN) with Xylene have been measured in 10 MHz to 20 GHz range using time domain dielectric spectroscopy. The complex permittivity spectra of CYN + Xylene binary mixtures were fitted to the Debye model. The dielectric relaxation parameters have been determined using the least squares fit method and are dependent on association and chain length of molecule. The experimentally obtained results were quantitatively used to know dipole-dipole interactions, nature of inter and intra molecular interaction between solute-solvent components in such a way when mixed in terms of hydrogen-bonding between CYN and Xylene. So the frequency dependent dielectric relaxation time gives the expected Arrhenius behavior, such that all concentrations of binary mixture shows linearity in plot of log (τ*T) versus 1000/T, which confirms the relaxation process as rate process according to Eyring’s theory.

Оптимизация процесса каталитического алкилирования циклопентадиена циклогексиловым спиртом

Based on the experimental data, a regression mathematical model has been developed for the process of obtaining cycloalkyl-substituted cyclopentadienes by catalytic alkylation of cyclopentadiene with cyclohexyl alcohol, reflecting the influence of the main technological factors (the ratio of the starting reagents, temperature, the amount of catalyst) on the yield of the target product. The statistical analysis of the obtained model is carried out, the adequacy of the developed model to the experimental data is proved. The optimal values of the input parameters are found, at which the maximum value of the yield of cycloalkylated cyclopentadienes is reached.

Experimental, theoretical and computational study of binary systems of alkanolamines and alkylamines with cyclohexanol at different temperatures

Density, ρ, speed of sound, u, and the difference in the temperature before and after the mixing process , ΔT, were measured for binary mixtures containing of cyclohexanol (CYC) + diethanolamine (DEA) or triethanolamine (TEA) or butylamine (BUT) or hexylamine (HEX) at (303.15–318.15) K except ΔT at 303.15 K. The excess molar volume, VmE, excess partial molar volume, Vm,iE, excess thermal expansion coefficient, αE, isothermal coefficient of excess molar enthalpy,(∂HmE∂P)T,x, deviation in isentropic compressibility,Δκs, excess molar enthalpy,HmE, and excess partial molar enthalpy, Hm,iE, were also calculated. The calculated data were satisfactorily correlated by Redlich – Kister equation. Some empirical models such as (Prigogine–Flory–Paterson) PFP, Wilson, (Non-Random Two Liquid) NRTL and (universal quasi chemical) UNIQUAC. Computational methods were performed using density function theory (DFT) and molecular dynamics (MD) simulation and were used to discuss and compare intramolecular and intermolecular interactions. An acceptable agreement was found between empirical and theoretical data.

Effect of cyclohexanol on phase stability and volatility behavior of hydrous ethanol-gasoline blends

Biofuels can contribute to reducing greenhouse gas emissions and bridging the gap between production and consumption. Ethanol is a renewable source of energy. It can reduce oil dependence and also can be appropriately used in gasoline as a blend. The high cost of dry ethanol has turned the researcher's attention to the more economic hydrous ethanol. However many works were focused on its impact on the engine performance and the exhaust emissions; few works were interested in the phase stability of those blends. This work aims to study the impact of blending cyclohexanol (CH) into hydrous ethanol-gasoline blends as a stabilizing agent. Four dual-alcohol (E5-3CH, E10-3CH, E15-3CH, and E20-3CH) blends were investigated besides their single hydrous ethanol (E0, E5, E10, E15, and E20) blends. The tests involved; water tolerance, distillation curve, and vapor pressure. Vapor lock protection potential, the area under the distillation curve (AUDC), and the area due to azeotrope formation (ADAF) were calculated. The obtained results show that cyclohexanol significantly increases the water tolerance of hydrous ethanol-gasoline blends. The blends of E5 and E10 which were separated at 30 °C converted into miscible and clear samples when they were blended with 3 vol% of cyclohexanol. These samples can also tolerate additional water. For E20, the addition of 3 vol% of cyclohexanol increased the water tolerance by about six times. Also, it was found that cyclohexanol does not have any negative effect on the volatility properties of the fuel blends. It was found that blending CH into the hydrous ethanol blends causes a significant increase in the AUDC and consequently, the area due to azeotrope formation (ADAF) decrease.

Efficient Synthesis of Cyclohexanol and Ethanol via the Hydrogenation of Acetic Acid‐Derived Cyclohexyl Acetate with the CuxAl1Mn2−x Catalysts

AbstractThe hydrogenation of cyclohexyl acetate (CHA), derived from the esterification of acetic acid and cyclohexene, not only alleviates the overcapacity of acetic acid, but also produces value‐added cyclohexanol (CHOL) and ethanol at a low cost. Herein, we prepared Cu1Al1, Cu1Mn1 and CuxAl1Mn2−x catalysts via a deposition‐precipitation method for the hydrogenation of CHA to CHOL and ethanol. As a result, the ternary CuxAl1Mn2−x catalysts exhibited superior behaviors to Cu1Al1 and Cu1Mn1. To our delight, Cu1Al1Mn1 had a 95.0 % CHA conversion and 93.6 % selectivity to CHOL along with 97.6 % selectivity to ethanol in a batch reactor. Based on detailed characterization, the ternary CuxAl1Mn2−x catalysts possessed more uniformed dispersion of Cu particles, less aggregation and larger BET specific surface area than the binary catalysts. Furthermore, Cu1Al1Mn1 possessed the highest Cu0/(Cu0+Cu+) molar ratio, the highest (Mn2++Mn3+)/Mn4+ molar ratio and the most abundant surface oxygen vacancies, facilitating the adsorption and activation of CHA and hydrogen. In addition, Cu1Al1Mn1 had excellent stability (>500 h) in a fixed‐bed reactor.