Secondary Hydrogen Research Articles

Preparation and characterization of hemicellulose films reinforced with amino polyhedral oligomeric silsesquioxane for biodegradable packaging

Biomass is one of the powerful alternatives to petroleum-based packaging materials. Herein, carboxymethyl hemicellulose (CMH) based films (CPF) were prepared using a convenient strategy. The chains of CMH provided the necessary supporting matrix, and the aminopropyl polyhedral oligomeric silsesquioxane (POSS-NH2) regulated the thermal and barrier properties of the CPF. The secondary amide groups and hydrogen bond were appeared in chemical structure, and SEM-EDS results indicated the preferable dispersion and compatibility of POSS-NH2 in CPFs. The thermal degradation temperature (Tonset > 260 °C), the coefficient of linear thermal expansion and glass transition temperature (Tg > 130 °C) have been improved by introduction of POSS-NH2. The tensile strength of CPF showed a higher level of 39.43 MPa with the POSS-NH2 loading of 20 wt%, which was 18.8 % higher than that of CMH film. More importantly, water vapor barrier property of films almost improved by two times, and its value is reduced to 18.82 g m−2 h−1. The shelf life of blueberry was effectively extended by the CPF coating for one week compared with commercial PE film. Therefore, CPF films displayed effective thermal performances, water vapor barrier characteristic and biodegradability, which might be exploited in packaging material for food application.

A theoretical kinetic study of 1-butyne, 2-butyne, and 3-methyl-1-butyne combustion

Propargylic radicals are an essential component in molecular weight growth kinetics and can react to form polycyclic aromatic hydrocarbons and soot. To establish rate rules for propargylic radicals, a total of 16 H-atom abstraction reactions of three alkynes, namely 1-butyne (1-C4H6), 2-butyne (2-C4H6), and 3-methyl-1-butyne (C5H8), were calculated using high-level quantum chemistry, in which four active radicals including Ḣ, ȮH, ĊH3, and HȮ2 were involved. Considering the completeness of the establishment of rate rules, the H-atom abstraction sites have included the primary and secondary site of 1-C4H6, primary site of 2-C4H6, and tertiary site of C5H8. The M06–2X/6–311++G(d,p) level of density function theory was used for the geometry optimization, vibrational frequency, and dihedral scan calculations. Single point energy calculations were carried out at the CCSD/cc-pVXZ (X = T, Q) level of coupled cluster theory. The rate coefficients for all of the abstraction reactions and the thermochemical quantities of 1-C4H6, 2-C4H6, and C5H8 and their corresponding radical products were calculated. The results indicate that H-atom abstraction by ȮH radicals has the fastest reaction rates for all three species. Moreover, abstraction from the tertiary site on C5H8 is the fastest, followed by abstraction of secondary hydrogen atoms on 1-C4H6 and primary hydrogen atoms on 2-C4H6, while abstraction of primary hydrogen atoms on 1-C4H6 are the slowest. NUIGMech1.3 (mechanism of version 1.3 proposed by National University of Ireland, Galway) has been updated based on our calculations, and ignition delay times (IDTs) were predicted using the updated mechanism. The predicted IDTs gave better agreement with the experiment data at pressures of 1, 30 and 50 bar. Sensitivity analyses were performed to understand observed model predicted differences at low to intermediate temperatures (700–1000 K) at 10 bar. The results show that the reactions 1-C4H6/2-C4H6 + HȮ2 and HȮ2 + HȮ2<=> H2O2 + O2 have a significant effect on promoting and inhibiting reactivity, respectively. Further Flux analyses show that the H-atom abstraction from 1-C4H6 and 2-C4H6 by ȮH radical is a dominant channel in changing branching ratios.

Dynamics and recognition of homeodomain containing protein-DNA complex of IRX4.

Iroquois Homeobox 4 (IRX4) belongs to a family of homeobox TFs having roles in embryogenesis, cell specification, and organ development. Recently, large scale genome-wide association studies and epigenetic studies have highlighted the role of IRX4 and its associated variants in prostate cancer. No studies have investigated and characterized the structural aspect of the IRX4 homeodomain and its potential to bind to DNA. The current study uses sequence analysis, homology modeling, and molecular dynamics simulations to explore IRX4 homeodomain-DNA recognition mechanisms and the role of somatic mutations affecting these interactions. Using publicly available databases, gene expression of IRX4 was found in different tissues, including prostate, heart, skin, vagina, and the protein expression was found in cancer cell lines (HCT166, HEK293), B cells, ascitic fluid, and brain. Sequence conservation of the homeodomain shed light on the importance of N- and C-terminal residues involved in DNA binding. The specificity of IRX4 homodimer bound to consensus human DNA sequence was confirmed by molecular dynamics simulations, representing the role of conserved amino acids including R145, A194, N195, S190, R198, and R199 in binding to DNA. Additional N-terminal residues like T144 and G143 were also found to have specific interactions highlighting the importance of N-terminus of the homeodomain in DNA recognition. Additionally, the effects of somatic mutations, including the conserved Arginine (R145, R198, and R199) residues on DNA binding elucidated the importance of these residues in stabilizing the protein-DNA complex. Secondary structure and hydrogen bonding analysis showed the roles of specific residues (R145, T191, A194, N195, R198, and R199) in maintaining the homogeneity of the structure and its interaction with DNA. The differences in relative binding free energies of all the mutants shed light on the structural modularity of this protein and the dynamics behind protein-DNA interaction. We also have predicted that the C-terminal sequence of the IRX4 homeodomain could act as a potential cell-penetrating peptide, emphasizing the role these small peptides could play in targeting homeobox TFs.

The Versatility of Mannich Reaction: An Overview

- One of the most significant processes for creating carbon-carbon bonds in organic synthesis is the Mannich reaction. It offers amino carbonyl compounds, crucial synthetic building blocks for many medicines. This Mannich bases are made by combining primary and/or secondary amines, formaldehyde, and active hydrogen molecules. Among those that are active hydrogen compounds include an acid, phenol, ketone, amide, etc. contribution involved the synthesis of 3,5 dimethyl carboxamide using a number of biologically active sulphonamides, which was followed by analysis of elements and spectrum analyses techniques using, IR, UV and 1HNMR. Escherichia coli, Staphylococcus aureus, and Bacillus subtilis were among the pathogenic microorganisms tested for the compounds’ antibacterial efficacy at different doses. We examined the bactericidal effectiveness of parent sulphonamides and derived Mannish bases. To establish whether synthetic Mannish bases were dangerous, the LD50 test was utilised.

Support effects on Ru-based catalysts for Fischer-Tropsch synthesis to olefins

The effects of supports (CeO2, ZrO2, MnO2, SiO2 and active carbon) on the structure and catalytic performance of Ru-based catalysts for Fischer-Tropsch synthesis to olefins (FTO) were investigated. It was found that the intrinsic characteristics of supports and the metal-support interaction (MSI) would greatly influence the catalytic performance. The catalytic activity followed the order: Ru/SiO2 > Ru/ZrO2 > Ru/MnO2 > Ru/AC > Ru/CeO2. As far as olefins selectivity was concerned, both Ru/SiO2 and Ru/MnO2 possessed high selectivity to olefins (>70%), while olefins selectivity for Ru/ZrO2 was the lowest (29.9%). Ru/SiO2 exhibited the appropriate Ru nanoparticles size (~ 5 nm) with highest activity due to the relatively low MSI between Ru and SiO2. Both Ru/AC and Ru/MnO2 presented low CO conversion with Ru nanoparticles size of 1–3 nm. Stronger olefins secondary hydrogenation capacity led to the significantly decreased olefins selectivity for Ru/AC and Ru/ZrO2. In addition, partial Ru species might be encapsulated by reducible CeO2 layer for Ru/CeO2 due to strong MSI effects, leading to the lowest activity.

CO2 hydrogenation to linear α-olefins on FeCx/ZnO catalysts: Effects of surface oxygen vacancies

Selective formation of hydrocarbons from CO2 hydrogenation via the FTS pathway has been attracting interest. Oxygen vacancies (Ov) on the catalyst surface show a subtle role during CO2 activation. Herein, the effects of Ov on FeCx/ZnO catalysts are presented for CO2 hydrogenation to linear α-olefins (LAOs). ZnO with surface Ov of varied concentrations was firstly obtained using heated H2-treatment and used to support active FeCx phases. FeCx/ZnO with appropriate surface Ov achieved CO2 conv. of 48.86% with LAOs sel. of 49.38% and C1 product below 10%. Characterizations confirmed that the Ov concentration exhibited a positive correlation with the interaction between the iron species and ZnO. With H2-treatment of ZnO at 500–600 °C, FeCx/ZnO-T showed 26–33% Ov in all the oxygen species, which increased the surface C/H ratio and promoted the formation of the key intermediate HCOO− and CHx species for chain growth. Excessive Ov accelerated secondary hydrogenation and increased CH4.

Insight into the Physicochemical Properties of Co-Based Catalysts in Fischer–Tropsch Synthesis

The effect of the different supports and catalyst-reducing agents on the Fischer–Tropsch (FT) reaction was investigated. The large surface area SiO2 support with a smaller pore volume deposited fine, evenly distributed Co3O4. Cubic-shaped Co3O4 appeared in clusters on the TiO2 support, whereas Co3O4 existed as single large particles on the Al2O3 support. The activity data obtained were discussed in terms of cluster size, particle size, particle shape, and mass transport limitations. The SiO2-supported catalysts showed a higher activity for the formation of paraffinic products when reduced in H2 at 250 °C. This is attributed to the formation of the CoO-Co active bond, which enhanced the activation of CO and the hydrogenation reactions. A higher activity was observed for the TiO2-supported catalyst at a higher reduction temperature (350 °C) when the mass of Co metal was higher. It afforded more paraffinic products due to enhanced secondary hydrogenation of olefins at higher reaction rates. The large Co3O4 supported on Al2O3 showed the least activity at both reduction temperatures due to strong metal-support interactions. The H2-reduced catalysts exhibited superior activity compared to all the syngas-reduced catalysts. Syngas reduction led to surface carbon deposition and the formation of surface carbides which suppressed the hydrogenation reactions and are selective to olefinic products.

Effects of fuel-hydrogen levels on combustion, operability, and emission parameters of CH4/H2/O2/CO2 stratified flames in a dual-swirl gas turbine burner

Towards the development of emission-free hydrogen gas turbines with wider operability limits, the combined effects of lean premixed combustion, dual combustion (combustion staging), hydrogen enrichment, and oxy-fuel combustion on the combustion and emission characteristics of CH4/H2/O2/CO2 flames are investigated in a dual annular counter-rotating swirl burner. The central stream is of a higher equivalence ratio (∅) of 0.9 for stable flame ignition, whereas the annular stream is of a lower ∅ of 0.65 to maintain the burner’s environmental performance. The stratified flame reactions are modelled using the partially premixed combustion model, which has been validated using the available experimental data. The inner recirculation zone becomes smaller as the hydrogen fraction (HF) becomes higher until it vanishes and there exists only an outer recirculation zone when the secondary hydrogen fraction approaches 100%. For 100% HF in both primary and secondary flow, the maximum combustion temperature within the combustor was observed to be as high as 2350 K. Increasing HF makes the flame more compact and anchored to the burner centre body with faster kinetics, less ignition delay time, and, accordingly, with increased potential for flashback. The product formation rate was found to increase in the inner shear layer at higher HF, implying a higher flame intensity and a more compact flame. The hydrogen fraction of the primary stream (maintained at higher equivalence ratio) is observed to be dominant in regulating CO mole fractions. Stable well-anchored flames are obtained over the considered fuel mixtures, indicating the role of stratified combustion in widening the operability of gas turbine combustors under stratified combustion conditions.

Probing the Roles of Residual Sodium in Physicochemical Properties and Performance of FeAlNa Catalyst for Fischer–Tropsch Synthesis

Although Fe-based catalysts have made significant progress in Fischer–Tropsch synthesis, the effect of residual sodium on the structural properties and catalytic performance of Fe-based catalysts has been controversial. Herein, we report the positive role of residual sodium in the structural properties and performance of FeAlNa catalysts for olefins synthesis from syngas. Meanwhile, the as-prepared catalysts were characterized by the multiple characterization technique to reveal the positive role of residual sodium on the structural properties. The characterization results revealed that the residual sodium improved the reduction behavior of Fe species and adsorption ability of CO, and inhibited the secondary hydrogenation due to its weak adsorption ability of H2. Moreover, the residual sodium inhibited the interaction between Fe and Al. Importantly, a high olefins/paraffins ratio of 6.19 and low CH4 selectivity of 12.8% were achieved on the residual sodium modified FeAlNa catalyst. An in-depth understanding of the structural properties and catalytic performance of residual sodium on FeAl-based catalysts can provide a theoretical basis for the development of novel efficient catalysts and large-scale applications for olefins synthesis from syngas.

A new neutron-gamma porosity measurement method for pulsed neutron logging tools

As an alternative method for the compensated neutron porosity measurement method, the neutron-gamma porosity measurement method is widely used in cased holes. However, the neutron-gamma porosity measurement method has some problems, such as the lack of detailed theoretical analysis and low sensitivity in high-porosity formations. The purpose of this paper is to clarify the theory of neutron-gamma porosity measurement, improve the measurement sensitivity, and eliminate the effects of environmental factors. Based on the neutron diffusion theory and the gamma transport theory, the distribution of capture gamma rays is described. A new neutron-gamma porosity measurement method is developed based on inelastic and capture gamma-ray distribution. The applicability of the new method in different environments is analyzed using the Monte Carlo method, and the effectiveness of this method is verified using the synthetic model. The results indicate that the capture gamma-ray ratio is only related to the source-detector distance, gamma-ray attenuation length, and neutron migration length. By combining density, different neutron cross sections, inelastic gamma-ray count ratio, and capture gamma-ray count ratio, the parameter secondary gamma-ray hydrogen index (SGH) related to hydrogen index can be extracted. The dynamic range of SGH is much higher than thermal neutron count ratio and the capture gamma-ray count ratio. The errors in porosity calculation by this method under different borehole and lithologic conditions are generally less than 2 pu. The calculation error of this method is close to that of the compensated neutron porosity measurement method. In addition, the applicability of the new method is analyzed without density data, and the results indicate that the calculation results are basically consistent with the results of calculation with density data. The new method has great potential for extensive applications in cased holes or open holes as an alternative for the compensated neutron porosity logging measurement method.

Cataract-causing variant Q70P damages structural stability of βB1-crystallin and increases its tendency to form insoluble aggregates

Congenital cataract is the primary cause of childhood blindness worldwide. As the predominant structural protein, βB1-crystallin plays an important role in maintaining lens transparency and cellular homeostasis. Numerous cataract-causing mutations of βB1-crystallin have been identified with unclear pathogenic mechanism. We previously identified the mutation Q70P (Q to P at residue position 70) of βB1-crystallin linked to congenital cataract in a Chinese family. In this work, we investigated the potential molecular mechanism of βB1-Q70P in the congenital cataract at the molecular, protein, and cellular levels. We purified recombinant βB1 wild-type (WT) and Q70P proteins and compared their structural characteristics and biophysical properties by spectroscopic experiments under physiological temperature and environmental stresses (ultraviolet irradiation, heat stress, oxidative stress). Notably, βB1-Q70P significantly changed the structures of βB1-crystallin and exhibited lower solubility at physiological temperature. Meanwhile, βB1-Q70P was prone to aggregation in eukaryotic and prokaryotic cells, and was more sensitive to environmental stresses, along with impaired cellular viability. Furthermore, the molecular dynamics simulation indicated that the mutation Q70P damaged secondary structures and hydrogen bond network of βB1-crystallin, which were essential for the first Greek-key motif. This study delineated the pathological mechanism of βB1-Q70P and provided novel insights into treatment and prevention strategies for cataract-associated βB1 mutations.

Isotopic evidence (δ13C, δ37Cl, δ2H) for distinct transformation mechanisms of chloroform: Catalyzed H2-water system vs. zero-valent iron (ZVI)

Catalytic hydrodechlorination is an efficient technology for degrading organochlorinated compounds, such as chloroform (CF), into harmless products. Compound-specific stable isotope analysis (CSIA) of multiple elements is widely used for the investigation of degradation mechanisms. Yet, its application in the study of catalytic hydrodechlorination is still limited. We have applied CSIA to derive chlorine, carbon, and hydrogen isotope enrichment factors (ε) during the degradation of CF over Pd/Al2O3 and over Rh/Al2O3. In addition, the enrichment factors for the same isotopes were derived for the reaction of CF with zero-valent iron (ZVI) for comparison. For the reactions of CF over Pd/Al2O3 and Rh/Al2O3, εC values (−21.9 ± 0.25 ‰ and −23.4 ± 2.3 ‰) and εCl values (−12.1 ± 1.7 ‰ and −10.3 ± 0.6 ‰) were determined, respectively. The corresponding εC and εCl values, for the dechlorination of CF with ZVI were −22.2 ± 2.8 ‰ and −4.7 ± 0.45 ‰, respectively. The apparent kinetic isotope effects (AKIE) of Cl suggest that the transformation mechanism in the catalyzed hydrogen-water system is a non-concerted reaction, unlike the known reductive dechlorination of CF with ZVI. Moreover, dual-isotope slopes (ΛC/Cl) for both catalyzed reactions (ΛPd = 1.8 ± 0.13 and ΛRh = 2.1 ± 0.14) are markedly different than for the ZVI (ΛZVI = 5.8 ± 0.41), reflecting that the reactions proceed in different mechanisms. For hydrogen isotopes, while there was no clear trend for the catalyzed reactions, an inverse secondary hydrogen isotope effect was observed for the reaction of CF with ZVI.

Microwave and Computational Study of Methanesulfonic Acid and Its Complex with Water

Spectra of methanesulfonic acid (CH3SO3H, MSA) and its complex with water have been studied by microwave spectroscopy and density functional theory calculations. For the monomer, spectra were obtained for both the parent and -OD isotopologues and, in each case, revealed a pair of tunneling states that are attributed to large amplitude motion of the hydroxyl hydrogen about the S-O(H) bond. Transitions crossing between tunneling states were not found in the parent spectrum and are estimated to be outside the range of the spectrometer, thus precluding the direct determination of the tunneling energy. For the -OD form, however, the tunneling energy was determined to be ΔE = 6471.9274(18) MHz from direct measurement of the cross-state c-type transitions. In its complex with water, the acidic hydrogen of the MSA forms a hydrogen bond with the water oxygen. A secondary hydrogen bond involving the water hydrogen and an SO3 oxygen completes a six-membered ring, forming a cyclic structure typical of hydrated oxyacids. No evidence of internal motion was observed. Rotational spectra of the CH3SO3H···D2O and CH3SO3D···D2O isotopologues were also obtained and analyzed. Comparison with theoretical calculations confirms the cyclic structure, though the orientation of the unbound water hydrogen is ambiguous.

Effect of MgFe-LDH with Reduction Pretreatment on the Catalytic Performance in Syngas to Light Olefins

MgFe-layered double hydroxides (LDH) were widely used as catalysts for Fischer–Tropsch synthesis to produce light olefins, in which the state of Fe-species may affect the resulting catalytic active sites. Herein, the typical MgFe-LDH was hydrothermally synthesized and the obtained MgFe-LDH was pretreated with H2 at different temperatures to reveal the effects of the state of Fe-species on the catalytic performance in Fischer–Tropsch synthesis. MgFe-LDH materials were characterized by X-ray diffraction (XRD), N2 adsorption–desorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), H2 temperature-programmed reduction (H2-TPR), and X-ray photoelectron spectroscopy (XPS). It was found that a MgO-FeO solid solution would be formed with the increase of the reduction temperature, which made the electrons transfer from Mg atoms to Fe atoms and strengthened the adsorption of CO. The pre-reduced treatment toward Mg-Fe-LDH enabled the FeCx active sites to be easily formed in situ during the reaction process, leading to the high conversion of CO. CO2 temperature-programmed desorption (CO2-TPD) and H2 temperature-programmed desorption (H2-TPD) analysis confirmed that the surface basicity of the catalysts was increased and the hydrogenation capacity was weakened, the secondary hydrogenation of the olefins was inhibited, and therefore as were the enhancement of O/P in the product and the high selectivity of light olefins (42.7%).

Density functional theory on reaction mechanism between p-doped LiNH&lt;sub&gt;2&lt;/sub&gt; clusters and LiH and a new hydrogen storage and desorption mechanism

Hydrogen energy is considered a clean energy with great development prospects. In the field of hydrogen energy applications, the solid-state chemical hydrogen storage method using hydrogen storage materials as media has received widespread attention due to its safety and high hydrogen storage density. In the research on metal-N-H system hydrogen storage materials, current studies focus on improving the kinetic conditions for hydrogen storage. In this study, the B3LYP hybrid functional method of density functional theory is used to investigate the reaction mechanism between P-doped LiNH&lt;sub&gt;2&lt;/sub&gt; clusters and LiH at a cluster level, and explore the effects of doping, in addition a new hydrogen storage mechanism called “secondary hydrogen transfer” is proposed. The full-geometry optimization of (LiNH&lt;sub&gt;2&lt;/sub&gt;)&lt;sub&gt;&lt;i&gt;n&lt;/i&gt;&lt;/sub&gt; (&lt;i&gt;n&lt;/i&gt; = 1–4) clusters and their P-doped clusters at the 6-31G(d,p) basis set level are carried out, and their corresponding most stable configurations are obtained. The distribution and stability of the frontier orbitals of the relevant reactants are calculated. Using the same method and basis set, the theoretical calculation and analysis of the reaction mechanism between P-doped (LiNH&lt;sub&gt;2&lt;/sub&gt;)&lt;sub&gt;&lt;i&gt;n&lt;/i&gt;&lt;/sub&gt; (&lt;i&gt;n&lt;/i&gt; = 1–4) clusters and LiH are conducted, including the configuration optimization of the stationary points in each reaction path, and the correctness of the connection between the stationary points is determined through frequency and intrinsic reaction coordinate calculations. The results show that P doping has a small effect on the lowest unoccupied molecular orbital, while the highest occupied molecular orbital has a significant transition towards the doping atom, and the electron-deficient region is concentrated at the P atom. P doping reduces the stability of the lithium amide clusters and enhances their ability to participate in chemical reactions and reaction activity, and the reaction dehydrogenation energy barrier decreases. The reaction dehydrogenation energy barrier between P-doped LiNH&lt;sub&gt;2&lt;/sub&gt; clusters and LiH is significantly lower than that between LiNH&lt;sub&gt;2&lt;/sub&gt; and LiH, which is consistent with the analysis of reactant stability. Additionally, it is found that the reaction between P-doped LiNH&lt;sub&gt;2&lt;/sub&gt; clusters and LiH tends to dehydrogenate through the —PH&lt;sub&gt;2&lt;/sub&gt; functional group and store hydrogen at the —NH&lt;sub&gt;2&lt;/sub&gt; functional group. Therefore, a new idea of “secondary hydrogen transfer” is proposed, in which effective transfer of hydrogen between —NH&lt;sub&gt;2&lt;/sub&gt; and —PH&lt;sub&gt;2&lt;/sub&gt; functional groups takes place during the cyclic hydrogen storage process, thus the reversibility of hydrogen storage is further improved and the hydrogen desorption energy barrier of the material is reduced.

Dissecting Bonding Interactions in Cysteine Dimers.

Neutral (n) and zwitterionic (z) forms of cysteine monomers are combined in this work to extensively explore the potential energy surfaces for the formation of cysteine dimers in aqueous environments represented by a continuum. A simulated annealing search followed by optimization and characterization of the candidate structures afforded a total of 746 structurally different dimers held together via 80 different types of intermolecular contacts in 2894 individual non-covalent interactions as concluded from Natural Bond Orbitals (NBO), Quantum Theory of Atoms in Molecules (QTAIM) and Non-Covalent Interactions (NCI) analyses. This large pool of interaction possibilities includes the traditional primary hydrogen bonds and salt bridges which actually dictate the structures of the dimers, as well as the less common secondary hydrogen bonds, exotic X⋯Y (X = C, N, O, S) contacts, and H⋯H dihydrogen bonds. These interactions are not homogeneous but have rather complex distributions of strengths, interfragment distances and overall stabilities. Judging by their Gibbs bonding energies, most of the structures located here are suitable for experimental detection at room conditions.

Selective synthesis of olefins via CO2 hydrogenation over transition-metal-doped iron-based catalysts

The catalytic hydrogenation of CO2 to olefins has received considerable attention. Herein, transition metal- and sodium-modulated iron-based catalysts were fabricated. Doping with zinc and copper favor the formation of Fe3O4 and Fe5C2 active phases, while adding manganese inhibits the formation of iron carbide. In addition, phase separation between copper and iron species occurs more readily under working conditions. Therefore, a zinc- and sodium-modulated Fe catalyst exhibited the best activity and stability. Moreover, copper was predicted to substantially decrease the energy barrier of the rate-determining step for the secondary hydrogenation of olefins and result in a much lower olefin-to-paraffin ratio. In addition, the ZnO/Fe5C2 interface facilitated the desorption of olefins from the catalyst surface and inhibited the undesirable secondary reaction of olefins, enabling a high selectivity toward olefins of 36.9 % C2–4= and 32.3 % C5+=. This study provides an exemplary new strategy for tuning the product selectivity of catalysts for olefin synthesis.

Thermochemical Liquefaction of Pomace Using Sub/Supercritical Ethanol: an Integrated Experimental and Preliminary Economic Feasibility Study.

Fossil sourced chemicals such as aromatics, are widely employed in the chemical industry for the production of commodity items. Recognizing the un-sustainability of existing approaches in the production of these chemicals, the current study investigated the valorization of apple pomace (AP) for their production. The present study assessed AP valorization by imposing variations in processing conditions of temperature (100–260 °C), time (0.5–12 h), alcohol/water ratio v/v (0:1–1:0), and Fe3+/H2O2 molar ratio (10:1–100-1), in accordance to the Box-Behnken experimental design. The optimal yield of the oil was 24.6 wt.%, at the temperature, time, alcohol/water ratio v/v, and Fe3+/H2O2 molar ratio of 260 °C, 4.7 h, 1, and 100, respectively. Notably, the application of gas chromatography-mass spectroscopy showed that the oil product contained mainly aromatics and interestingly also alkanes, indicating that the experimental conditions imposed promoted secondary hydrogenation reactions of oxygen-containing species during AP valorization. A consideration of the comparative economics of the proposed AP valorization and the existing AP management approach, using approximate estimation techniques, highlighted the potential of a ~ 59% reduction in the unit cost of AP management. The study therefore presents a compelling basis for future investigations into AP waste management using the thermochemical liquefaction technology.Graphical abstract

Hydrogenation of CO2 to light olefins on ZZ/MnSAPO-34@Si-2: Effect of silicalite-2 seeds on the acidity and catalytic activity

Light olefin is a primary building block for synthesizing various chemical intermediates and products. CZZ@MnSAPO-34 and ZZ@MnSAPO-34 core–shell catalysts were prepared for hydrogenation of CO2 via Silicalite-2 seed-assisted in-situ hydrothermal synthesis method. The evaluation results showed that CZZ@MnSAPO-34 favors the generation of light alkanes, while ZZ@MnSAPO-34 benefits the production of light olefins. Further, the core–shell catalysts coating with Silicalite-2 shell denoted as ZZ@Si-2, CZZ@Si-2, and MnSAPO-34@Si-2 were synthesized by the in-situ hydrothermal synthesis technique. The microstructure, acidity, and element distribution of the above core–shell catalysts were investigated by XRD, NH3-TPD, and SEM-EDS analysis. The physically mixed ZZ/MnSAPO34@Si-2 exhibited the highest CO-free selectivity for light olefins up to 70.0%, with CO2 conversion of 17.3% at 380 °C, 2.0 MPa, GHSV = 4800 h−1. The effective synergistic interactions and weak acidity of the MnSAPO34@Si-2 zeolite favored the formation of light olefins via promoting CC coupling of methanol intermediates and inhibited the secondary hydrogenation. Meanwhile, the strong hydrogenation capacity of the CZZ elevated the selectivity to C20-C40 (82.1%) on CZZ/MnSAPO-34@Si-2 catalyst. It is found that the modulation of active metal components and inter-component synergy contributes to the regulation of product distribution.

Back Cover: Direct Conversion of Syngas to Higher Alcohols via Tandem Integration of Fischer–Tropsch Synthesis and Reductive Hydroformylation (Angew. Chem. Int. Ed. 31/2022)

Tandem catalysis of solid NaPr-CoRu@Al2O3 and molecular [HCo(CO)3PR3] catalysts allows the direct conversion of synthesis gas to alcohols. Walter Leitner, Andreas J. Vorholt, Gonzalo Prieto et al. show in their Research Article (e202201004) that the combination of Fischer–Tropsch and hydroformylation catalysts generates alcohols from synthesis gas with exceptional selectivity. While the bimodally porous solid catalyst generates 1-olefins with high efficiency, in situ hydroformylation of olefins to alcohols circumvents secondary hydrogenation and allows to push the alcohol selectivity even further.