Analysis Of Product Distribution Research Articles

Unlocking biomass valorization: Machine Learning insights for Reductive Catalytic Fractionation of cotton stalks

Lignocellulosic biomass valorization has become an intensive area of research due to the importance of renewable nature and availability of biomass. However, biomass fractionation and depolymerization produce numerous datasets, that are difficult to visualise and interpret for the scale-up of the process. Therefore, machine learning algorithms, which can discover hidden patterns in data are applied to these datasets. Reductive Catalytic Fractionation (RCF) of lignocellulosic biomass is an emerging methodology to valorize biomass completely and effectively. Herein, the present work includes the Correlation Analysis and the Principal Component Analysis (PCA) of product distribution obtained from RCF of cotton stalks. Interactions between process variables and delignification (DL), sugar retention (SR), total phenolic monomers (PM), and individual phenolic monomers yield were evaluated. Correlations among DL, SR, and PM yields were also evaluated at different reaction conditions through PCA, which were explained using the reaction mechanism and molecular chemistry of lignin.

Solvent-free deoxygenation of biolipid into liquid alkanes over bifunctional Ni/B2O3-ZrO2 catalyst

The efficient deoxygenation of renewable biolipids into liquid alkanes within the diesel range is a key protocol for producing high-quality biofuels. In this work, the conversion of methyl palmitate and raw palm oil were accomplished utilizing a bifunctional catalyst of Ni catalysts supported on B2O3-ZrO2 under solvent-free conditions. Among various Ni loading ratios investigated, the catalyst featuring a 10 % Ni loading achieved 100 % conversion of methyl palmitate and 84.4 % of liquid yield, with approximately 65 % being C15 alkanes. Additionally, more than 91 % of hydrocarbons were also generated from raw palm oil. These results can be attributed to the synergistic interplay between the acid sites, following B2O3 modification, and the presence of Ni species. Furthermore, the analysis of product distribution, gas product detection and the kinetics calculation strongly supports that the deoxygenation process of methyl palmitate primarily follows the hydrodecarbonylation route, leading to the predominant formation of C15 alkane.

Synergistic Catalytic Effects on Nitrogen Transformation during Biomass Pyrolysis: A Focus on Proline as a Model Compound.

To investigate the control mechanisms of NOx precursors and the synergistic effects of composite catalysts during proline pyrolysis, a systematic series of experiments was conducted utilizing composite catalysts with varying Fe-Ca ratios. Product distribution analysis was employed to elucidate the catalysts' mechanisms in reducing NOx precursor emissions. The synergistic interactions between Fe and Ca were quantitatively assessed through comparative theoretical and experimental release calculations. The results indicate that an increase in the Fe content in the catalyst led to a rise in amine concentrations from 0.9% to 2.95%, implying that Fe facilitates the generation of amine-N through ring-opening and substitution reactions. When the Fe to Ca ratio was balanced at 1:1, nitrogen predominantly participated in the formation of purines via cyclization and substitution reactions. Additionally, all composite catalysts exhibited a suppressive effect on the release of NOx precursors, attributed to their significant enhancement of solid product retention. Fe-Ca composite catalyst synergistically inhibits the release of gaseous nitrogen. Notably, the strongest synergistic effect was observed with a 1:3 Fe to Ca ratio, which reduced the release of NH3 by 38.7% and HCN by 53.6% during proline pyrolysis. This study offers valuable insights into the control of NOx precursors and the optimization of nitrogen-rich biomass pyrolysis processes.

Catalytic Fast Pyrolysis of Tar-Rich Coal with a Bauxite Residue for Upgrading High-Value Products: Product Distribution and Kinetic Analysis.

Fast pyrolysis technology can reduce the secondary reactions, improve the volatile product yield, and reduce the semicoke yield. Still, the high proportion of heavy tar components affects the development of fast pyrolysis industrialization. Therefore, this paper put forward a catalytic upgrading method of coal based on the solid waste bauxite residue (BR) as a catalyst. This study investigated the impact of varying particle sizes of pulverized coal and the addition of the BR catalyst on the product distribution and kinetics of coal fast pyrolysis. The results found that the tar yield was the highest at 600 °C when the particle size of pulverized coal was 75-150 μm, which was 19.44%. In the range of 550-650 °C, the relative content of benzene and toluene xylene (BTX) in liquid products increased with the temperature. With the increase of the proportion of the BR catalyst, the yield of semicoke in coal pyrolysis products increased, the yield of the gas phase also increased, and the yield of the liquid phase decreased.

Mechanism Studies in Electrochemical Depolymerization Processes of Alkali and Organosolv Lignin

AbstractTo better understand the process and mechanism of lignin structural changes and relative product formation during PbO2 anode electrolysis, a Ti/Sb−SnO2/PbO2 composite electrode has been prepared and utilized for the alkaline electrolytic oxidation of both alkali lignin (AL) and bagasse organosolv lignin (OL). By combining electrochemical measurements, in‐situ FTIR, 2D‐HSQC NMR, and product distribution analysis, we not only investigate the impact of influence factors on the process of lignin depolymerization, but also reveal the depolymerization mechanism from the whole process of lignin structural changes in details. Under certain electrolysis conditions, the highest vanillin yield, 10.1 mg g−1, has been obtained through the electrolysis of alkali lignin, whereas the highest syringaldehyde yield of 4.0 mg g−1 has been achieved during the electrolysis of organic solvent lignin. In particular, AL mainly performs depolymerization through the selective cleavage C−C bonds to produce a series of G unit monomer products of vanillin, acetovanillone, and vanillic acid. By contrast, the depolymerization of OL shows significant selectivity in H units. Particularly, the production of the major H unit monomer product of 4‐vinylphenol has been confirmed by IR spectroelectrochemical studies from the oxidation and decarboxylation of p‐coumaric acid unit.

Boosting the Faradaic Efficiency of Br--Mediated Photoelectrochemical Epoxidation by Local Acidity on α-Fe2O3.

The redox mediated photoelectrochemical (PEC) or electrochemical (EC) alkene oxidation process is a promising method to produce high value-added epoxides. However, due to the competitive reaction of water oxidation and overoxidation of the mediator, the utilization of the electricity is far below the ideal value, where the loss of epoxidation's faradaic efficiency (FE) is ≈50%. In this study, a Br-/HOBr-mediated method is developed to achieve a near-quantitative selectivity and ≈100% FE of styrene oxide on α-Fe2O3, in which low concentration of Br- as mediator and locally generated acidic micro-environment work together to produce the higher active HOBr species. A variety of styrene derivatives are investigated with satisfied epoxidation performance. Based on the analysis of local pH-dependent epoxidation FE and products distribution, the study further verified that HOBr serves as the true active mediator to generate the bromohydrin intermediate. It is believed that this strategy can greatly overcome the limitation of epoxidation FE to enable future industrial applications.

Co-pyrolysis characteristic of sugarcane waste with polyethylene terephthalate: thermal decomposition, product distribution, synergistic effect, and kinetics analysis.

This work has focused on the co-pyrolysis of sugarcane waste (SW) with polyethylene terephthalate (PET) to gain insight on its thermal decomposition, product distribution, kinetics, and synergistic effect. SW and PET were blended at different ratios (100:0, 80:20, 60:40, 40:60, and 0:100), and the Coats-Redfern method was used to determine the kinetics parameters. To ascertain the synergistic effect between SW and PET, product yields and composition of chemicals were compared with the synergistic effect of the individual components of pyrolysis. The bio-oil yield was significant at 60% of PET, with a difference of 19.41 wt% compared to the theoretical value. The synergistic impact of SW:PET on ester formation and acid compound inhibition was the most dominant at the 60:40 ratio. The kinetics analysis revealed that the diffusion mechanism, power law, and order of reactions were the most probable reaction models that can explain the pyrolysis of SW, and PET, and their blends. The resultant co-pyrolysis oil contained slightly larger hydrogen and carbon contents with low oxygen, and sulphur, and nitrogen contents, which improved the quality of the bio-oil. The results of this work could be used as a guide in selecting proper reaction conditions with optimal synergy during the co-pyrolysis process.

Detailed insights of polydimethylsiloxane (PDMS) degradation mechanism via ReaxFF MD and experiments

Polydimethylsiloxane (PDMS) serves as a widely used silicone polymer in ablative thermal protection material. Nevertheless, the intricate degradation mechanism governing PDMS at ultra-high temperatures remains unclear. Herein, PDMS pyrolysis was in-depth investigated by employing a combination of experimental methodologies and ReaxFF molecular dynamics (ReaxFF-MD) simulations. PDMS model was firstly validated by product distribution analysis and kinetics analysis. Molecular reaction tracking unveils that the pyrolysis pathway primarily is triggered by the cleavage of the Si-C bond, leading to cyclization reactions and fractures within the Si-O framework at elevated temperatures. The pathways leading to the formation of gaseous, liquid, and solid products during thermal cracking are systematically unveiled. Drawing from these insights, DFT calculations reveal Si-C bond dissociation energies (BDEs) of 98.8, 102.2, and 108.2 kcal/mol for Si-CH3, Si-C2H3, and Si-C6H5, respectively. MD simulations further indicate that the heightened Si-C BDEs across various silicone rubbers impede their decomposition, thereby augmenting the thermal stability of the material. This study augments our comprehension of the PDMS pyrolysis mechanism and offers theoretical insights for enhancing its thermal stability.

Catalytic Decarboxylative Asymmetric Allylic Alkylation for the Synthesis of Axially Chiral Biaryls

AbstractHerein, we report a palladium‐catalyzed atroposelective decarboxylative asymmetric allylic alkylation. A chiral palladium complex with a phosphoramidite ligand effectively desymmetrizes biaryls containing cinnamyl carbonate with excellent enantioselectivities. The addition of a catalytic amount of base accelerates the reaction process without loss of enantioselectivity. Cross‐over experiment provides mechanistic insight, suggesting that allyl palladium complex primarily dissociates from the original biaryl substrate and deliver allyl species intermolecularly. Analysis of product distribution at various time points indicates that secondary kinetic resolution plays a crucial role in achieving remarkable atroposelectivity.

Analysis of kinetics, mechanism, thermodynamic properties and product distribution for pyrolysis of Ni–Fe impregnated coconut husk

This study explored on pyrolytic thermal degradation of coconut husk (CH), treated with Ni–Fe electroplating wastewater and Ni–Fe synthetic water, for bioenergy generation. Initially, green coconut husk absorbed solutions resembling electroplating effluent and synthetic Ni–Fe at 105 °C. Physiochemical properties of the husk and ICP-MS analysis of water were thoroughly examined before TG/DTG analysis. The impact of catalysts on pyrolysis was assessed through TG/DTG measurement, the obtained results were utilized to study the kinetics and thermodynamic parameters using the iso-conversional approaches (FWO, KAS, Starink) and Criado plots were used to discuss the reaction mechanism. Metal impregnated biomass with wastewater (MICHw) found to have high activation energy compared to that of metal impregnated with synthetic water (MICHs). For MICHw, average activation energies were calculated as 132.22, 151.37, and 149.78 kJ/molefegurefff for FWO, KAS, Starink, respectively, however, for MICHs the values were 114.79, 114.03.71, and 114.75 kJ/mol. The potential energy barrier (6–10 kJ/mol) between activation energy and reaction enthalpy showed a favourable environment for product development. Various experiments on native green coconut husk (NGCH) and impregnated coconut husk under different conditions showed a higher liquid oil yield for MICHw, attributed to the Ni–Fe catalyst at 650 °C and smaller particle sizes. This research provides key insights into enhancing bioenergy production through the pyrolytic conversion of impregnated coconut husk, highlighting the pivotal role of wastewater-derived catalysts.

Effect of anaerobic digestion pretreatment on pyrolysis of distillers’ grain: Product distribution, kinetics and thermodynamics analysis

To systematically examine the effects of anaerobic digestion (AD) pretreatment on product distribution and kinetics of distillers’ grains (DG) and its digestates collected at different AD durations, Py-GC/MS and TG analyses were conducted. Py-GC/MS analysis revealed a reduction in the proportion of oxygenated and nitrogenous compounds in all digestates and increase the share of hydrocarbons: 46.72% (SD-2), 65.53% (SD-4), 43.20% (SD-6) and 50.05% (SD-8) than DG (38.61%). To assess activation energy, Friedman, Kissinger-Akahira-Sunose and Flynn-Wall-Ozawa models were employed with average values ranging from 159.54 to 170.96 kJ mol−1 for DG, 156.59–165.42 kJ mol−1 for SD-2, 15.67–166.47 kJ mol−1 for SD-4, 153.28-159-45 kJ mol−1 for SD-6, and 156.02–167.37 kJ mol−1 for SD-8, which were lowered than DG. Thermodynamic studies showed positive ΔH and ΔG values, suggesting that the pyrolysis of DG and digestates is non-spontaneous. The negative ΔS values implied that the degree of disorder in products resulting from bond dissociation was lower than initial reactants. These findings provide valuable insight into the potential of AD as a pretreatment method and offer an understanding of the pyrolysis behavior of digestates. This study not only offers practical guidance but also contributes to the theoretical framework for utilizing AD as a pretreatment method for pyrolysis.

Relationship between molecular structure and pyrolysis performance for high-energy-density fuels

High-energy-density endothermic hydrocarbon fuels (HDEHFs) are the ideal on-board coolants for the thermal management of advanced aircrafts. However, the pyrolysis performace of high-energy-density (HED) fuels with different molecular structures remains ambiguous. Herein, we investigated the pyrolysis performance of five HED fuels with different cyclic structures, i.e., bicyclohexyl (BCH), perhydrofluorene (PHF), decahydronaphthalene (DHN), exo-tetrahydrodicyclopentadiene (exo-THD) and cyclopropyl-tetrahydrodicyclopentadiene (CTHD), to reveal the molecular structure-reactivity relationship. The pyrolysis conversion (650 °C, 4 MPa) of the tested fuels is in the order of CTHD > PHF > BCH > DHN > exo-THD, which is highly associated with their C + H atom numbers, nH+C (except for CTHD with high-tension ring). With the analysis of product distribution as well as DFT calculation, the decomposition reaction pathways of the fuels were proposed. The heat sink of the fuels follows the order of BCH > PHF > DHN > exo-THD > CTHD, which is closely correlated with nH/C6.9 × nH+C3.8. Meanwhile, the fitting results between molecular structures and physicochemical properties of the fuels were also demonstrated. This study could provide a guidance on the design and development of HDEHFs fuels for the high-performance aerospace vehicles with long flight distance and hypersonic speed.

Production of high-carbon-number bio-aviation fuels from furans using sulfated zirconia and silica-alumina aerogel catalysts

Lignocellulose can help produce fuels in biorefineries through its fractionated components such as cellulose, hemicelluloses, and lignin. For instance, hemicellulose-derived xylose has been studied for obtaining petroleum-substituting fuels. Therefore, in this study, catalytic hydroalkylation/alkylation (HAA) of xylose-derived 2-methylfuran (2-MF) with butanal was targeted to selectively produce high-carbon-number diesel fuels. To that end, silica–alumina (SiAl) aerogels with different Si/Al ratios and a series of sulfated zirconia (SZ) compounds calcined at various temperatures were prepared as catalysts to overcome the limitations of conventional hazardous homogeneous acid catalysts. The activity of the SiAl catalysts in forming the desired HAA product, 5,5-bissylvylbutane (denoted as BB), was found to be directly related to the number of acid sites and acid density. Moreover, increasing the Si/Al molar ratio, which reduced the acid density and number of acid sites, led to lower 2-MF conversions and BB yields. The optimal 2-MF conversion and BB yield with the SiAl catalysts (67 % and 45 %, respectively) were achieved using a Si/Al ratio of 8:2 mol/mol. Furthermore, SZ calcined at 700 °C (denoted as SZ-700) exhibited the highest activity among the SZ catalysts (72 % 2-MF conversion, 63 % BB yield), despite having the fewest acid sites and lowest acid density. This was presumably because of the physical structure of SZ-700, which featured mixed monoclinic and tetragonal phases, many oxygen vacancies, and a large accessible external surface area, which facilitated the HAA reactions. Hydrogenation and hydrodeoxygenation (HDO) of BB were performed thereafter using Pd/C and Ru/SiO2–Al2O3 catalysts, respectively. The resulting deoxygenated hydrocarbons comprised 15.1 % light hydrocarbons (C4–C8) and 83.1 % heavier hydrocarbons (C9–C20). Simulated distillation analysis of the post-HDO product distribution indicated that the liquid-phase product contained 70 % high-carbon-number bio-aviation fuels.

Machine learning-enabled analysis of product distribution and composition in biomass-coal co-pyrolysis

Co-pyrolysis of biomass and coal presents a promising opportunity for large-scale biomass utilization while reducing fossil fuel consumption. However, this process is highly complex and influenced by various factors, including the physicochemical properties of biomass and coal, their blending ratio, and operating parameters. To effectively comprehend and optimize the biomass-coal co-pyrolysis process, many experiments are required to achieve the desired product quantity and quality. In addressing this challenge, machine learning technology emerges as a valuable solution, as it can learn the relationships between input and output variables from available examples without explicit knowledge of the underlying mechanisms. This study conducts a comprehensive literature review to establish an extensive database encompassing biomass-coal compositions and pyrolysis reaction conditions. Using the collected data, robust statistical analyses are applied to understand better the underlying mechanisms governing the biomass-coal co-pyrolysis process. Four machine learning methods, namely support vector regression, artificial neural network, random forest regression, and gradient boosting regression, are employed to model the process. The best-performing model is subjected to an extensive feature importance analysis to identify the essential input features associated with each output response. The gradient boosting regression technique demonstrates superior performance with excellent results, characterized by higher coefficients of determination (R2 > 0.96) and lower errors (RMSE < 3.01 and MAE < 2.27). The temperature range of 450 to 550 °C, biomass blending ratios between 30 and 60%, and heating rates of 30 to 50 °C/min were identified as the conditions that maximize pyrolysis oil yield. Furthermore, the feature importance analysis reveals that the operating temperature and the biomass blending ratio are the most significant descriptors in the biomass-coal co-pyrolysis process.

Methane-assisted catalytic light oil desulfurization: Catalyst design, sulfur product distribution analysis and mechanistic study

The desulfurization of natural oil feedstock for fuel purposes is crucial for environmental protection and sustainable development. Methane is the main component of natural gas resources with low added value. Distinctive characteristics are demonstrated if methane can be directly used for oil desulfurization, instead of being converted into hydrogen via methane stream reforming for hydrodesulfurization. Here, the methane-assisted catalytic desulfurization process is specifically developed for light oils such as marine diesel oil. First, different catalyst supports are selected and compared, among which Al2O3 is confirmed to provide the most favorable reaction performances. Then, the reaction is operated under different gas atmospheres including CH4, N2, and H2, to reveal the uniqueness of methane for a desulfurization process. Next, model compound oils are selected with thiophene as the sulfur-containing oil component. Heptane and toluene are used as solvents to represent paraffin-rich and aromatic-rich oil, respectively. It is found that the structural characteristic of the oil significantly influences the desulfurization performance and product distribution, based on which the respective reaction mechanism networks are proposed. It is concluded that despite the unparalleled desulfurization performance under hydrogen, the methane-assisted desulfurization process demonstrates distinctive characteristics to prevent light end loss and oversaturation as well as the formation of H2S as the primary desulfurization product, which can be better utilized under certain circumstances.

Products Distribution and Synergistic Effects Analysis During Co-Pyrolysis of Agricultural Residues and Waste Tire Using Gas Chromatography/Mass Spectrometry

Abstract The co-thermal chemical conversion of biomass and waste tires is an important direction for the utilization of waste resources to produce renewable energy. In this study, the product distribution and synergistic effects during the co-pyrolysis of agricultural residues and waste tire were analyzed by a pyrolyzer coupled with a gas chromatograph/mass spectrometer (Py-GC/MS). Pyrolysis and co-pyrolysis products were analyzed at 550 °C and 650 °C for maize stalk (MS), wheat straw (WS), waste tire (WT) feedstocks, as well as mixtures of wheat straw-waste tire (WS:WT mass ratio of 1:1), and maize stalk-waste tire (MS:WT mass ratio of 1:1). The results showed that the co-pyrolysis of agricultural residues and waste tire promoted the release of phenols, aldehydes, and ketone derivatives, and reduced the formation of H2 and H2O. In addition, a relatively high content of aromatic hydrocarbons was obtained at 650 °C temperature, while 550 °C was optimal when considering the formation of ketones. The results showed a synergistic effect in the co-pyrolysis of biomass and waste tire.

Conquering the solubility barrier of di-n-octylamine as structure-directing agent in hierarchical silicoaluminophosphate synthesis by using phase-transfer synthesis

Silicoaluminophosphates (SAPOs) are a class of microporous solids employed as solid acid catalysts or adsorbents in petrochemical and coal chemical processes, which are often generated in hydrothermal synthesis using water-soluble organic structure-directing agents (OSDA), resulting in the formation of micron sized, rod-like crystals running along pore-channel direction for unidimensional SAPOs. The use of a low-cost, barely soluble di-n-octylamine (DOA) as OSDA in a water/toluene biphasic media to crystallize SAPO-31 is reported. The product is disclosed to be a hierarchically porous material built up of self-assembled nanocrystals (∼110 nm) with enhanced diffusion property and preserved acidity comparable to that of a standard sample derived using di-n-hexylamine as OSDA. The formation is mediated by the formation of a Pickering emulsion structure that favors crystal nucleation over growth, thus overcoming the solubility barrier of candidate OSDA. The obtained material exhibited higher isomer yield in catalytic hydroisomerization of n-dodecane compared to the control sample. Product distribution analysis discloses that mono-branched isomers are generated mainly inside the micropores, while di-branched isomers are produced via key-lock catalysis on pore-mouth sites. The increase in isomerization selectivity is attributed to the formation of more mono-branched isomers and their lowered cracking probability associated with enhanced diffusion property. This new synthetic protocol expands the toolkit of candidate OSDAs towards hydrophobic molecules and exemplifies porogen-free fabrication of hierarchical SAPOs. The uncovered origin of shape-selectivity offers a guidance towards manipulating hydroisomerization product slates.

Analysis of Pyrolytic Product Distribution for B3 and Non-B3 Medical Waste Pyrolysis

&lt;p class="E-JOURNALAbstractBodyEnglish"&gt;The coronavirus disease (COVID-19) has badly impacted many sectors, particularly medical waste generation in healthcare facilities. The increasing amount of medical waste poses a serious threat to health and environmental sustainability. Traditional waste processing (burning) cannot be used for B3 medical waste and is often mixed with non-B3 medical waste. This is because it potentially generates dangerous chemicals emitted into the atmosphere. Meanwhile, pyrolysis as a superior thermochemical technology is an effective solution for treating both B3 medical waste and non-B3 medical waste. The waste used in this study has good characteristics, as indicated by the low water and high fixed carbon content. The pyrolysis process yields products with economic value, such as solid, liquid, and gas products. Therefore, this study aims to determine the levels of products that can be produced from B3 and non-B3 medical waste. The results showed that rubber bands produce the highest proportion of liquid products at 44%, the highest solid products were obtained from LDPE plastic waste with a proportion of 65%, while the highest gas product was produced by mask waste at 45%. Based on the results, waste with high product yields can be used as an alternative energy source, such as gasoline, LPG, briquettes, and battery-based materials.&lt;/p&gt;

Tandem aromatization of pentane with temperature shifting three-stage fluidized bed reactor

Conversion of pentane into aromatics was carried out in a temperature shifting, three-stage fluidized bed reactor, where the temperature was set to be 500 °C, 560 °C, and 350 °C, from the bottom to the top, respectively. The catalysts of Ga/P/ZSM-5 were packed into the first stage (near the bottom of the reactor) and second stage (middle), while catalysts of HZSM-5 were packed into the third (top) stage. Pentane was nearly completely transformed at the first stage, while the aromatics yield was sustainably increased from the first to the second, and finally to the third stage. Detailed product distribution analysis suggested that the aromatization of pentane mainly occurred in the first stage, intermediate products such as C3-C4 paraffins could be effectively transformed via the aromatization reaction in the second stage. Olefins were further transformed into aromatics by the alkylation reaction in the third stage. Within 10 cycles of reaction-catalyst regeneration, stable aromatization with high efficiency was realized for 105 h.

Effect of Ru particle size on cis/trans ratio of products in the hydrogenation of 2,2,4,4-tetramethyl-1,3-cyclobutanedione to 2,2,4,4-tetramethyl-1,3-cyclobutanediol

Ru/AC catalysts with different particle sizes were prepared by tuning the calcination temperature and atmosphere. The performance in the hydrogenation of 2,2,4,4-tetramethyl-1,3-cyclobutanedione (CBDK) to 2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO) was evaluated. Ru/AC catalysts with relatively large Ru particle sizes showed a higher selectivity towards trans-CBDO. The analysis of product distribution at different substrate conversion and DFT calculation revealed that the cis-CBDO is a kinetic favorable product. During the stepwise hydrogenation of both carbonyls, the selectivity of thermodynamic favorable trans isomer increases. The enhanced activity of isomerization reaction over the large Ru particles also accounts for the low cis/trans ratio of products in the CBDK hydrogenation reaction.