Catalytic Hydrolysis Research Articles

Basic property and oxygen defect-enhanced nitrogen-doped layered hydroxide-derived oxides MAlO (M = Ni, Co) for carbonyl sulfide hydrolysis at low temperature

Catalytic hydrolysis has been considered the most efficient method for the removal of carbonyl sulfide (COS). However, high-efficiency catalyst was urgently desired. In the present work, nitrogen-doped layered hydroxide-derived oxides (Ni(Co)Al-N) were successfully prepared. It was revealed that N enriched basic sites and oxygen vacancies were well developed for the prepared catalyst. And the catalytic activity was improved significantly. Among the catalysts, the NiAl-N catalyst exhibited the best catalytic activity (can reach 780 min COS 100 % conversion) and lowest activation energy. The concept of OH generation potential was firstly proposed to evaluate the contribution of basic sites to the improvement of catalytic activity. The OH generation potential was greatly improved due to N doping. More importantly, the enhanced basic property and oxygen defect content jointly contributed to the enhancement of catalytic activity. Besides, COS cannot adsorb on the catalyst surface and the reaction obeyed an E-R mechanism. Namely, H2O first adsorbed on basic sites to form OH groups, then COS reacted directly with the formed OH groups, and to generate H2S and CO2 products. HCO3– and HSCO2− were the main intermediate species, and the rate-determining step was the reaction between OCOSH* and H* to form CO2 and H2S.

Catalytic hydrolysis of methyl mercaptan and methyl thioether on hydroxyl-modified ZrO2: a density functional theory study.

The purification and removal of organic sulfur from natural gas is conducive to increasing the added value of natural gas and reducing environmental pollution. In this study, the adsorption properties of methyl mercaptan (CH3SH), dimethyl sulfide (C2H6S) and H2O on the surface of hydroxyl-modified ZrO2 were investigated using density functional theory (DFT) calculations. Additionally, a reaction mechanism was proposed for hydroxyl-modified ZrO2 catalyzing the hydrolysis of CH3SH and C2H6S. The chemisorption of H2O molecules on the catalyst surface is attributed to H-O and H-Zr bonds. The chemisorption of CH3SH and C2H6S on the catalyst surface is attributed to Zr-S bonds. Competitive adsorption between the three gases exists only between CH3SH and C2H6S. It reveals the water-resistant properties of hydroxyl-modified ZrO2 in desulfurization. The adsorption energies of the three gas molecules on the hydroxyl-modified ZrO2 surface are in the order of CH3SH - (Zr) > C2H6S - (Zr) > H2O - (OH). The natural hydrolysis of CH3SH and C2H6S is a heat-absorbing process that cannot occur spontaneously. The rate-determining step for CH3SH catalytic hydrolysis is the formation of CH3O. The fracture of CH3SHO is the rate-determining step for C2H6S catalytic hydrolysis. The depletion of the surface hydroxyl groups can be replenished by the dissociation of H2O molecules. Hydroxyl-modified ZrO2 facilitated the hydrolysis process of CH3SH to a greater extent than that of C2H6S. This study provides theoretical guidance for industrial applications and the design of hydroxyl-containing hydrolysis catalysts.

A novel experimental approach for the catalytic conversion of lignocellulosic Bambusa bambos to bioethanol

Bambusa bambos (B.B) biomass is cellulose rich lignocellulosic material, containing 47.49% cellulose, 17.49% hemicellulose, 23.56% lignin was used as a potential substrate for bioethanol production. The research paper investigates the use of B.B biomass as a substrate for bio-ethanol production through a two-phase catalytic conversion process. Four water-regulated regimes were identified to optimize the conversion of lignocellulosic biomass to biofuel precursors. The catalytic hydrolysis of B.B using CuCl2 was conducted for 10 hours at 110˚C, in aprotic ionic liquid (1-Butyl-3-methylimidazolium chloride) medium. The concentrations of glucose and 5-hydroxymethylfurfural (5-HMF) were measured while varying the amount of water addition. Water played a crucial role in the conversion of cellulose to glucose and 5-HMF by influencing product yields through the interplay of transport properties like heat conduction and viscosity. The highest glucose yield was achieved at 60.82% when operating at a water inclusion rate of 115.72 µL water/h for a duration of 6 hours at 110˚C. On the other hand, the maximum HMF yield was observed as 5.84% at water inclusion rate of 77.15 µL water/h for 5 hours at 110˚C. Yeast mediated glucose fermentation resulted in a bioethanol concentration of 5.5 mg/mL utilizing 15 mg/mL of catalytically produced glucose at a temperature of 30°C. After catalytic hydrolysis, the ionic liquid was also efficiently recycled for a sustainable economy.

Facile preparation of UiO-66-NH2-stabilized high internal phase molecularly imprinted polymers for synergistic catalytic hydrolysis detoxification of organophosphate nerve agents

Developed a UiO-66-NH2 stabilizing pickering high internal phase OP imprinting polymer multi-porous composite catalysis system, which integrates MIPs and MOFs successfully, the two materials with remarkable catalytic hydrolysis activity for OPs.

Techno-enviro-economic analysis of second-generation bioethanol at plant-scale by different pre-treatments of biomass from palm oil waste

This study evaluates three pathways: supercritical water treatment (SCW), CO2-water (scCO2-H2O), and catalytic hydrothermal hydrolysis (CHH) to produce second-generation bioethanol using palm tree fronds (PTF) as feedstock. The analysis focuses on technical performances using process simulation with Aspen Plus™, environmental evaluation by applying a Life Cycle Assessment (LCA) framework and an economic analysis using the levelized cost. The results of the technical performances reveal CHH as the best pathway for bioethanol production, with the highest ethanol yield at 273 L/tonne dry PTF and a substantial NER of 2.2, outperforming SCW and scCO2-H2O. From an environmental evaluation, CHH reveals lower carbon footprints of 61 g CO2 per MJ. Economically, CHH is competitive, with an ethanol production cost of1.11 $/L, comparable to the enzymatic hydrolysis process. These findings provide the technical, environmental, and economic aspects of a promising route for lignocellulosic bioethanol production while suggesting pathways for further optimisation for future research.

Mechanism and experimental study of bimetallic solid catalysts on urea catalytic hydrolysis to ammonia

Mechanism and experimental study of bimetallic solid catalysts on urea catalytic hydrolysis to ammonia

Comparative analysis of Zn(II)-complexes as model metalloenzymes for mimicking Jack bean urease.

The inhibitory action of Schiff base complexes of 3d metals against the urease enzyme is well explored in the scientific community. However, the ability of such complexes in mimicking active metallobiosites of urease enzymes, possessing ureolytic behavior, still remains unexplored. With this aim firstly, two Zn(II)-complexes (PPR-HMB-Zn and PZ-HMB-Zn) have been developed from two different Schiff base ligands (HL1 = 2-((E)-(2-(piperidin-1-yl)ethylimino)methyl)-5-methylphenol and HL2 = 2-((E)-(2-(piperizin-1-yl)ethylimino)methyl)-5-methylphenol) and structurally characterized using single crystal XRD. The hydrolytic enzymatic activity of both complexes was demonstrated by the gradual increase in the absorption maxima at 425 nm for the formation of the p-nitrophenolate ion from catalytic hydrolysis mediated by the Zn(II) complexes with a disodium salt of p-nitrophenyl phosphate as a model substrate. Associated kinetic parameters, pH dependency and a relevant hydrolysis mechanism have also been explored. After confirming the hydrolytic ability, the complexes were exploited to mimic the hydrolytic activity of Jack bean urease that catalytically hydrolyses urea into ammonia and CO2. The change in the pH of the solution owing to the formation of ammonia under the complex catalysed hydrolytic action of urea has been monitored spectrophotometrically using the pH dependent structural change of phenol red. The amount of ammonia has been quantified using the Nessler's reagent spectrophotometric method. The ureolytic reaction mechanism has been investigated using density functional theory (DFT) calculations using the B3LYP and TPSSH methods for the systematic calculation of the interaction energy. In contrast to PZ-HMB-Zn, PPR-HMB-Zn functions more effectively as a catalyst due to the existence of a lattice-occluded water molecule in its crystal structure and the protonation of the non-terminal N to attract urea by H-bonding, which was further confirmed by AIM analysis.

Boron nanosheets as a phosphatase mimicking nanozyme with ultrahigh catalytic activity for prodrug-based cancer therapy.

Boron nanosheets (BNSs) are reported as a new phosphatase mimicking nanozyme. Surprisingly, the catalytic rate of BNSs is up to 17 times those of known phosphatase mimicking nanozymes. By adding polyols and Lewis bases, the catalytic activity of BNSs was attributed to the Lewis acidity of the B centers of the BNSs. Theoretical investigation shows that the B centers are responsible for the catalytic hydrolysis of phosphoesters. Moreover, the biomimetic activity of the BNSs was further explored for enhancing anticancer therapy through nanozyme-catalyzed prodrug conversion.

Catalytic hydrolysis of carbonyl sulfide in blast furnace gas over Sm-Ce-Ox@ZrO2 catalyst.

Carbonyl sulfur (COS) is a prominent organic sulfur pollutant commonly found in the by-product gas generated by the steel industry. A series of Sm-doped CeOx@ZrO2 catalysts were prepared for the hydrolysis catalytic removal of COS. The results showed that the addition of Sm resulted in the most significant enhancement of hydrolysis catalytic activity. The 3% Sm2O3-Ce-Ox@ZrO2 catalyst exhibited the highest activity, achieving a hydrolysis catalytic efficiency of 100% and H2S selectivity of 100% within the temperature range of 90-180 °C. The inclusion of Sm had the effect of reducing the acidity of the catalyst while increasing weak basic sites, which facilitated the adsorption and activation of COS molecules at low temperatures. Appropriate doping of Sm proved beneficial in converting active surface chemisorbed oxygen into lattice oxygen, thereby decreasing the oxidation of intermediate products and maintaining the stability of the hydrolysis reaction.

Design strategies and biological applications of β-galactosidase fluorescent sensor in ovarian cancer research and beyond.

Beta-galactosidase (β-galactosidase), a lysosomal hydrolytic enzyme, plays a critical role in the catalytic hydrolysis of glycosidic bonds, leading to the conversion of lactose into galactose. This hydrolytic enzyme is used as a biomarker in various applications, including enzyme-linked immunosorbent assays (ELISAs), gene expression studies, tuberculosis classification, and in situ hybridization. β-Galactosidase abnormalities are linked to various diseases, such as ganglioside deposition, primary ovarian cancer, and cell senescence. Thus, effective detection of β-galactosidase activity may aid disease diagnoses and treatment. Activatable optical probes with high sensitivity, specificity, and spatiotemporal resolution imaging capabilities have become powerful tools for visualization and real time tracking in vivo in the past decade. This manuscript reviews the sensing mechanism, molecular design strategies, and advances of fluorescence probes in the biological application of β-galactosidase, particularly in the field of ovarian cancer research. Current challenges in tracking β-galactosidase and future directions are also discussed.

Molecular design of peptide therapeutics via N-terminal modification.

Glucagon-like peptide-1, glucose-dependent insulinotropic polypeptide, and glucagon are three naturally occurring peptide hormones that mediate glucoregulation. Several agonists representing appropriately modified native ligands have been developed to maximize metabolic benefits with reduced side-effects and many have entered the clinic as type 2 diabetes and obesity therapeutics. In this work, we describe strategies for improving the stability of the peptide ligands by making them refractory to dipeptidyl peptidase-4 catalyzed hydrolysis and inactivation. We describe a series of alkylations with variations in size, shape, charge, polarity, and stereochemistry that are able to engender full activity at the receptor(s) while simultaneously resisting enzyme-mediated degradation. Utilizing this strategy, we offer a novel method of modulating receptor activity and fine-tuning pharmacology without a change in peptide sequence.

EFFECTIVE POLYMER DECORATION ON NICKEL-IMINE COMPLEX TO ENHANCE CATALYTIC HYDROGEN EVOLUTION

Since fossil fuels are rapidly depleting, finding alternative energy sources is becoming increasingly important. Among these alternatives, hydrogen (H2) is the most viable option. In hydrogen evolution systems, supported metal catalysts enhance the catalytic activity in the hydrolysis reaction by increasing the surface area. Therefore, this research focuses on preparing three different polymer-decorated Nickel-Imine complex catalysts (Ni@EC, Ni@EC-250, Ni@ECM) to improve their efficiency. To achieve the catalysts, a Nickel-Imine complex [1] was supported on three different polymers (EC, EC-250, and ECM). The catalysts (Ni@EC, Ni@EC-250, Ni@ECM) were then utilized to generate hydrogen from NaBH4 hydrolysis. The hydrogen evolution rates for Ni@EC, Ni@EC-250, and Ni@ECM catalysts were found as 6879; 15576; 8830 and 15459; 28689; 23417 mL H2 gcat-1.min-1, respectively at 30 oC and 50 oC. Results indicate that the Ni@EC-250 catalyst exhibited the best activity. Consequently, the subsequent steps of the catalytic hydrolysis reaction were studied using Ni@EC-250. The activation energy of the Ni@EC-250 catalyst was estimated at 39.255 kJ.mol-1. The reusability tests demonstrate that Ni@EC-250 remains active in sodium borohydride hydrolysis even after five runs. Technical abbreviations are defined upon first use. This study elucidates the reaction mechanism and kinetic data of catalytic sodium borohydride hydrolysis at various temperatures.

Catalytic hydrolysis of agar using magnetic nanoparticles: optimization and characterization

BackgroundAgar is used as a gelling agent that possesses a variety of biological properties; it consists of the polysaccharides agarose and porphyrin. In addition, the monomeric sugars generated after agar hydrolysis can be functionalized for use in biorefineries and biofuel production. The main objective of this study was to develop a sustainable agar hydrolysis process for bioethanol production using nanotechnology. Peroxidase-mimicking Fe3O4-MNPs were applied for agar degradation to generate agar hydrolysate-soluble fractions amenable to Saccharomyces cerevisiae and Escherichia coli during fermentation.ResultsFe3O4-MNP-treated (Fe3O4-MNPs, 1 g/L) agar exhibited 0.903 g/L of reducing sugar, which was 21-fold higher than that of the control (without Fe3O4-MNP-treated). Approximately 0.0181% and 0.0042% of ethanol from 1% of agar was achieved using Saccharomyces cerevisiae and Escherichia coli, respectively, after process optimization. Furthermore, different analytical techniques (FTIR, SEM, TEM, EDS, XRD, and TGA) were applied to validate the efficiency of Fe3O4-MNPs in agar degradation.ConclusionsTo the best of our knowledge, Fe3O4-MNP-treated agar degradation for bioethanol production through process optimization is a simpler, easier, and novel method for commercialization.

Renin and renin blockade have no role in complement activity

Renin, an aspartate protease, regulates the renin-angiotensin system by cleaving its only known substrate angiotensinogen to angiotensin. Recent studies have suggested that renin may also cleave complement component C3 to activate complement or contribute to its dysregulation. Typically, C3 is cleaved by C3 convertase, a serine protease that uses the hydroxyl group of a serine residue as a nucleophile. Here, we provide seven lines of evidence to show that renin does not cleave C3. First, there is no association between renin plasma levels and C3 levels in patients with C3 Glomerulopathies (C3G) and atypical Hemolytic Uremic Syndrome (aHUS), implying that serum C3 consumption is not increased in the presence of high renin. Second, in vitro tests of C3 conversion to C3b do not detect differences when sera from patients with high renin levels are compared to sera from patients with normal/low renin levels. Third, aliskiren, a renin inhibitor, does not block abnormal complement activity introduced by nephritic factors in the fluid phase. Fourth, aliskiren does not block dysregulated complement activity on cell surfaces. Fifth, recombinant renin from different sources does not cleave C3 even after 24 hours of incubation at 37 ⁰C. Sixth, direct spiking of recombinant renin into sera samples of patients with C3G and aHUS does not enhance complement activity in either the fluid phase or on cell surfaces. And seventh, molecular modeling and docking place C3 in the active site of renin in a position that is not consistent with a productive ground state complex for catalytic hydrolysis. Thus, our study does not support a role for renin in the activation of complement.

MOF‐Templated Hierarchical Porous Hollow Core‐Shell Framework Cobalt Oxide for Enhancing Hydrogen Generation from Borohydride‐Based Hydrolysis

AbstractDesigning and fabricating a competent cobalt‐based catalyst for sodium borohydride (NaBH4) hydrolysis is of great importance. The present work reports the synthesis of hierarchical porous hollow core‐shell framework cobalt oxide (HCSCO) via etching and calcination processes, which is then employed for catalyzing NaBH4 hydrolysis. The surface morphology and the hollow core‐shell framework of HCSCO were revealed by scanning electron microscope (SEM) and transmission electron microscope (TEM) analyses; the crystalline structure and the formation of Co3O4 in HCSCO were determined by X‐ray diffraction (XRD) and Raman spectroscopy; the surface area and porosity of HCSCO were verified by N2 adsorption‐desorption isotherm; and X‐ray photoelectron spectroscopy (XPS) was utilized to examine the chemical states of HCSCO. The as‐prepared HCSCO showed prominent catalytic hydrolysis of NaBH4 to generate H2 with a H2 generation rate of 441 ml min−1 gcatalyst−1 and a low activation energy (Ea) of 34.8 kJ mol−1. This Ea value of HCSCO is substantially lower than that of other catalysts, including noble metal catalysts or composites reported in the literature. Besides, HCSCO could remain its superb activity (~100 % H2 generation efficiency) over multiple hydrolysis cycles without significant changes of morphology and microstructure. The catalytic hydrolysis mechanism for H2 generation from NaBH4 using HCSCO is also proposed. This work provides a valuable strategy for the synthesis and fabrication of state‐of‐art catalysts for H2 generation from the hydrolysis of NaBH4.

A Comparison of Dilute Aqueous Isethionic Acid and Sulfuric Acid in Hydrolysis of Three Different Untreated Lignocellulosic Biomass Varieties.

Efficient catalytic hydrolysis of lignocellulosic biomass to sugars is a major challenge in the production of sustainable biofuels and chemical feedstocks. In this study isethionic acid was compared with H2SO4 for hydrolysis of polysaccharides in corn stover, switch grass, and poplar. The catalytic activities of acids were compared by analysis of total reducing sugar (TRS) and glucose yields in a sequence of experiments in water at 90-190 °C using 0.050 mol of H+/L isethionic acid and H2SO4. In comparison to using H2SO4, the use of isethionic acid catalyst lowered the maximum TRS percent yield temperatures by 25, 24, and 21% for corn stover, switch grass, and poplar. A similar effect was observed for glucose percent yields as well. This temperature reduction is due to lowering of the activation energy in the polysaccharide depolymerization reaction and most likely due to hydrogen-bonding-type dipolar interactions between the isethionic acid -OH group and -OH groups in biomass polysaccharides.

Catalytic Hydrolysis of Sodium Borohydride

Catalytic Hydrolysis of Sodium Borohydride

Beef quality monitoring using immobilization lipase on modified polypropylene non-woven fabric based on time-temperature indicator

A lipase-based time-temperature indicator (TTI) was developed via the immobilization of lipase on polyethylene imine/glutaraldehyde/polypropylene non-woven fabric for the catalytic hydrolysis of glyceryl triacetate. pH of the reaction system gradually decreased and the color changed from green to orange or salmon pink. Four TTIs were selected by changing the concentration of glyceryl triacetate methanolic solution, the concentration of lipase-phosphate buffer solution, and the amount of phosphate buffer added, storing at 5–25 °C and measuring the coloration difference every 24 h. The Arrhenius activation energy (Ea) of obtained TTIs was calculated as 26.28, 47.98, 38.87, and 42.00 kJ/mol. For the application of TTIs to fresh beef monitoring, the kinetic properties of beef were studied and an Ea value of 37.60 kJ/mol was obtained. The similarity of these Ea shows accuracy in the prediction of beef quality with TTI color development.

Catalytic hydrolysis of carbonyl sulfide over Ce-Ox@ZrO2 catalyst at low temperature

Catalytic hydrolysis of carbonyl sulfide over Ce-Ox@ZrO2 catalyst at low temperature

Study on the influence factors of Pt-based catalyst on dehydrogen performance of ammonia borane hydrolysis-Which is more important, geometric effects or electronic effects?

The basic catalytic properties of catalysts are largely determined by their geometric and electronic structures. However, the geometric and electronic interference between the active atoms and their neighbors makes it difficult to determine the extent of the effects of geometric and electronic effects on the catalytic activity. In this paper, Pt-based (Fe, Co, Ni, Cu and Zn) alloy nanoparticles (NPs) were prepared by a one-step reduction method. Through X-ray diffraction (XRD) analysis, high-resolution transmission electron microscopy (HRTEM) analysis and X-ray photoelectron spectroscopy (XPS) analysis, the superior lattice compression effect of Pt3Cu was found. It has great influence on catalytic performance. However, with the increase of Cu content, electron transfer increases, and the effect of electron effect is greater than the effect of lattice compression. Among them, Pt3Cu has the best performance as the content of Pt is high, which is controlled by geometric effects. When the content of Pt is few, the catalytic performance of PtNi3 is the best, showing the results regulated by electronic effects. The d-band center and Bader charge are determined by DFT calculation, and the experimental results are verified. The results show that the position of the d-band center is in a volcanic trend with HER properties. Pt3Cu has a suitable d-band central position, which affects the adsorption and desorption behavior of H2O molecules in the hydrolysis reaction, thus affecting its catalytic performance. These results provide new insights into the relationship between the geometric and electronic effects of catalysts and their catalytic ammonia borane hydrolysis activity.