Simple Hydrolysis Research Articles

Isolation, chemical characterization and hydrolysis of the trichothecene 7α-hydroxy, 15-deacetylcalonectrin (3ANX) from Fusarium graminearum DAOMC 242077

Fusarium graminearum and related species produce regulated mycotoxins that contaminate important food commodities resulting in serious agricultural and animal productivity losses. F. graminearum DAOMC 242077 was isolated from soft wheat in Eastern Canada and an investigation of this strains secondary metabolites confirmed it produced the recently discovered type-A trichothecene 7α-hydroxy, 15-deacetylcalonectrin (3ANX; 1). In an effort to prepare large amounts of its deacetylated product 7α-hydroxy, 3, 15-dideacetylcalonectrin (NX; 2), F. graminearum DAOMC 242077 was grown using conditions favoring the biosynthesis of trichothecenes to enable large amounts of 3ANX (1) to be purified. The structure of 3ANX (1) was confirmed by interpretation of spectroscopic data, physical properties and LC-HRMS. A simple hydrolysis scheme was developed to convert 3ANX (1), to NX (2). The objective of this study was to generate and chemically characterize 3ANX (1) and NX (2) reference materials for the scientific community for toxicology studies, analytical method development and exposure assessments.

Transition‐Metal‐free C5, C7‐Dihalogenation and the Switchable C5 Halogenation of 8‐Hydroxyquinolines

AbstractThe first example on the C5, C7‐dihalogenation of 8‐hydroxyquinolines based on an in situ O‐acyl 8‐hydroxyquinoline formation is realized under catalyst‐free condition in toluene. Modifying the reaction conditions by directly utilizing O‐acylated 8‐hydroxyquinolines in the presence of AlCl3 enables the electrophilic halogenation in the C5 position, leading to the tunable synthesis of C5 halogenated products. The O‐acyl group can be easily removed from the product to provide halogenated quinolines containing free hydroxyl group by simple hydrolysis.

Porous α-Fe2O3 nanorods@graphite nanocomposites with improved high temperature gas sensitive properties

In order to improve the high temperature sensitivity of α-Fe2O3 based gas sensor, the porous α-Fe2O3 nanorods@graphite nanocomposites were synthesized using a simple low temperature hydrolysis method. A series of analyses were performed to characterize the morphology, structure and composition. As a result, uniform porous α-Fe2O3 nanorods with a length of about 200–300 nm directly grown on the surface of graphite nanoplatelets. When tested as sensing materials for gas sensors, the nanocomposites display a high sensitivity of 16.9 toward 50 ppm acetone at a work temperature of 260 °C, which was 2.2 times of that of pure α-Fe2O3. Even at a work temperature of 320 °C, a stable sensitivity as high as 10.4 toward 50 ppm acetone could be maintained. The improved high temperature sensitivity of porous α-Fe2O3 nanorods@graphite nanocomposites can be attributed to p-n heterojunction, the porous structure of α-Fe2O3 nanorods, the high temperature stability of graphite and large specific surface areas.

A Validation and Estimation of Total Eicosapentaenoic and Docosahexaenoic acids Using LC-MS/MS with Rapid Hydrolysis Enzymatic Method for Hydrolysis of Omega Lipids in Human Plasma and its Application in the Pharmacokinetic Study

Background:In this study, we have developed a novel, rapid enzymatic hydrolysis method for conversion of omega lipids (omega fatty acid triglycerides, phospholipids, omega conjugates) in to free fatty acids at room temperature using lipase and esterase enzymes. </P><P> Objective: To develop simple enzymatic hydrolysis and rapid sample extraction method for quantification of free (un-esterified) and conjugated (esterified) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) to provide the total EPA and DHA lipids present in human plasma. Quantification of total EPA/DHA was performed using liquid chromatography and tandem mass spectrometer instrument.Methods:The plasma sample is digested with lipase and esterase enzymes and extracted by using combined precipitation and liquid-liquid techniques. The LC-MS/MS method was optimized using EPA-D5 and DHA-D5 as labeled internal standards for EPA/DHA respectively. The analytical method is validated, utilized for simultaneous quantification of total EPA and DHA lipids in plasma collected from healthy human volunteers clinical study.Results:The reproducibility of the established enzymatic hydrolysis method was demonstrated by incurred sample reanalysis and the results for total EPA and DHA lipid were 93.33% and 96.67% respectively. The pharmacokinetic and statistical analysis was performed using baseline corrected concentration of total EPA and DHA lipids.Conclusion:The enzymatic hydrolysis method for conversion of omega fatty acid triglycerides, phospholipids, omega conjugates in to free fatty acid was reported first time for the quantitative application. The shorter time for sample workup procedure, simple enzymatic hydrolysis at room temperature and 3 minutes chromatography run time are well suitable for bioavailability/ bioequivalence studies.

Fabrication of uniform Si-incorporated SnO2 nanoparticles on graphene sheets as advanced anode for Li-ion batteries

SnO2-based anodes with high capacity are appealing for Li-ion batteries (LIBs). However, the large volume change and inferior cycling stability limit their practical application. To mitigate these problems, a novel nanocomposite of silicon-incorporated SnO2 with graphene sheets (STOG) has been successfully fabricated as anode material for LIBs. Through a simple hydrolysis process, ultrafine Si-incorporated SnO2 (STO) nanoparticles are uniformly loaded on the graphene sheets. Further it is found that Si incorporation brings about the SiOSn bonding in the SnO2 matrix and strengthens the SnOC bonding between STO and graphene. These merits can enhance the structural stability and electron/ion transport of STOG nanocomposite, facilitating the reversible conversion of Sn–SnO2. As a result, this STOG material delivers a high discharge capacity of 1117.8 mAh g−1 and retains 92.5% of the second capacity after 100 cycles at 0.1 A g−1. Furthermore, an excellent rate capacity of 683.9 mAh g−1 can be obtained at a high current of 1 A g−1. This work provides an effective way to design high-performance SnO2-based anode material for LIBs.

Study on the biodegradability and water adsorption of ldpe/sago starch blend

The aim of this study is to develop starch incorperated with low density polyethylene (LDPE) composites with enhanced degradable properties. The degradable test has been carried out by hydrolysis. The water uptake of the composites has been determined. The degradability of the compatible thermoplastic LDPE/starch was investigated by weight loss percent (WLP). Simple and alkaline hydrolysis of the composites apparently involves surface starch granules; embedded granules are not easily accessible because of the poor moisture absorption of the matrix. Exposure of the composites to hydrolysis resulted in massive deterioration typified by turbidity, discoloration, embrittleness and dimensional changes. Moisture uptake increased with increased starch content and immersion time. The time taken for the composites to equilibrate was about three months even when they were immersed completely in water. The mechanical properties of the composite also dropped with increasing moisture uptake. SEM imaging was also carried out on the samples before and after degradation. High content of starch also was found to increase the rate of biodegradability of LDPE/sago starch mould.

Effect of substrate on formation and nanofiltration performance of graphene oxide membranes

Graphene oxide (GO) has been considered as a promising material to develop advanced nanofiltration membranes benefiting from its extraordinary physicochemical properties. GO membranes for practical application need porous substrates to provide sufficient mechanical strength. Compared to extensive studies on the manipulation of GO selective layer, the influence of substrates on the performance of GO membranes has been received much less attention. Actually, significant differences in physical and chemical properties of the substrates should lead to distinct assembly structure of resulting GO membranes with uneven performance. Therefore, the effect of substrate on GO membranes formation and separation are worth study and optimization. Herein, we employed typical inorganic ceramic tube and polymeric polyacrylonitrile (PAN) and polycarbonate (PC) substrates to support GO membranes and studied the effects of their surface morphologies and roughness, surface chemical composition, as well as bulk pore structure on the formation and nanofiltration performance of resulting GO membranes. Substrates properties were revealed to have remarkable impacts on the adhesion and transport property of GO membranes. We found that the surface morphological and chemical structure of substrates induced GO assembly and determined GO adhesion, and the bulk pore structure of substrates dominated the whole transport resistance of GO membrane. Especially, the PAN substrate possessing abundant oxidized functional groups after simple hydrolysis, contributed to a robust interfacial adhesion with GO selective layer and enabled GO membrane to withstand harsh stability measurements including cross-flow, high feed pressure and long-period continuous operation. Besides, the smooth surface morphology along with the bulk highly porous structure of PAN substrate offered a favorable platform for GO assembly, resulting in competitive nanofiltration performance with water permeance of 15.5 Lm−2 h−1bar−1 and dye rejection of 99.5%. Overall, this work gives new insights of design and fabrication of durable GO membranes for practical applications.

Carbonate and silicate weathering in glacial environments and its relation to atmospheric CO2 cycling in the Himalaya

ABSTRACTThis paper presents new insights into the global carbon cycle related to CO2 consumption from chemical denudation in heavily glacierised Himalayan catchments. Data from previous studies of solute concentrations from glacierised catchments were reprocessed to determine the regional scale of CO2 consumption and solute hydrolysis. The results show that ~90% of the SO42− is derived from crustal sulphide oxidation and ~10% from aerosols and sea salts. However, HCO3− flux calculation estimates contribution from sulphide oxidation to carbonate dissolution (SO-CD) (~21%), similar to the contributions from silicate dissolution and simple hydrolysis (~21 and ~20%, respectively). Furthermore, the atmospheric CO2 consumption estimations suggests 10.6 × 104 mole km−2 a−1 (19%) through silicate weathering, 15.7 × 104 mole km−2 a−1 (28%) through simple hydrolysis, 9.6 × 104 mole km−2 a−1 (17%) through SO-CD reaction and 5.9 × 104 mole km−2 a−1 (11%) through carbonate carbonation reaction. Our solute provenance calculations clearly indicate that HCO3− production and CO2 consumption via silicate weathering reactions is balanced by the simple hydrolysis and coupled SO-CD process. This shows a counter mechanism operating in subglacial environments of the Himalaya as a source of CO2 to runoff rather than a sink.

Hydrogen generation via hydrolysis of Mg2Si

A convenient, high-density and low-cost hydrogen supply technology is essential to hydrogen energy system by providing hydrogen to fuel cell component. Magnesium silicide (Mg2Si) can be a good hydrolysis candidate due to its low cost and ability of releasing hydrogen gas during hydrolysis process. However, previous studies have demonstrated that Mg2Si could easily produce large amount of silanes during hydrolysis reaction, which may cause serious problem of explosive danger when in contact with air. Here it is the first time that Mg2Si was used for generation of hydrogen by a simple and convenient one-step hydrolysis reaction. In this study, hydrolysis kinetics and mechanisms of Mg2Si in NH4Cl and NH4F solutions were investigated. The silanes could be almost completely turned into hydrogen by introduction of fluorine ion during the hydrolysis reaction of Mg2Si, leading to very low silanes content in the produced hydrogen. The kinetic studies indicated that when the concentration of the NH4F solution increased to 13.0%, the hydrogen generation rate and the reaction yield were improved significantly and reached the best performance, producing 466 mL g−1 H2 in 10 min and 616 mL g−1 H2 in 30 min at 25 °C. The activation energy was calculated to be 37.3 ± 0.8 kJ mol−1. Furthermore, the hydrogen yield and the hydrolysis rate of Mg2Si can be further improved by high-energy ball milling. After ball milling for 2 and 5 h, the hydrogen generation yield in 30 min increased to 698 and 771 mL g−1, respectively, and the activation energy was decreased to 23.9 ± 0.6 kJ mol−1 and 12.9 ± 0.1 kJ mol−1, respectively. The results revealed that NH4F can be a promising reagent for promoting the hydrolysis of Mg2Si for onsite hydrogen supply.

Enhanced Antibacterial Performance and Cytocompatibility of Silver Nanoparticles Stabilized by Cellulose Nanocrystal Grafted with Chito-Oligosaccharides.

The agglomeration of silver nanoparticles (AgNPs) results in poor antibacterial performance, and the accumulation of silver in the human body threatens human health. Preparing a matrix is a technique worth considering as it not only prevents the aggregation of AgNPs but also reduces deposition of AgNPs in the human body. In this paper, carboxy-cellulose nanocrystals (CCNC) were prepared by a simple one-step acid hydrolysis method. Chito-oligosaccharides (CSos) were grafted onto the surface of CCNC to form CSos-CCNC composite nanoparticles. CCNC and CSos-CCNC were used as stabilizers for deposing AgNPs and two types of complexes—AgNPs-CCNC and AgNPs-CSos-CCNC—were obtained, respectively. The influence of the two stabilizer matrices—CCNC and CSos-CCNC—on the morphology, thermal behavior, crystal structure, antibacterial activity, and cell compatibility of AgNPs-CCNC and AgNPs-CSos-CCNC were examined. The results showed that the AgNPs deposited on the CSos-CCNC surface had a smaller average diameter and a narrower particle size distribution compared with the ones deposited on CCNC. The thermal stability of AgNPs-CSos-CCNC was better than that of AgNPs-CCNC. AgNPs did not affect the crystalline structure of CCNC and CSos-CCNC. The antibacterial activity of AgNPs-CSos-CCNC was better than that of AgNPs-CCNC based on antibacterial studies using Escherichia coli, Staphylococcus aureus, and Klebsiella pneumoniae. The cytotoxicity of AgNPs-CSos-CCNC was remarkably lower than that of AgNPs-CCNC.

ENHANCED FIRE RETARDANCY BY USING LARGE SURFACE AREA OF POLYALUMINUM HYDROXIDE ON SILICA SPHERES

Fire retardancy was greatly enhanced by using large surface area of polyaluminum hydroxide (PAH) attaching on the surface of uniform size silica spheres. The PAH was synthesized on the surface of silica spheres by simple hydrolysis and condensation reaction using KOH or NH4OH as a catalyst. Although partial segregation between silica spheres and PAH was observed when KOH was used as a catalyst, there was no such segregation was observed when NH4OH was used as a catalyst. Characteristic absorption peaks of Al–OH and Si–O–Al were detected by FTIR spectra after completely washing silica spheres. Field emission scanning electron microscope (FESEM) images show large amount of long chain of PAH. Various amounts of PAH were attached on the surface of silica spheres and mixed with cellulose acetate for testing fire retardancy. The fire retardancy was greatly enhanced by increasing the amount of PAH and proved by FESEM images.

The Combination of Amorphous Manganese Oxide and Hollow Fiber with Enhanced Activity and Stable Reusability as Heterogeneous Catalyst for Dye Oxidation

Powdered or granular manganese oxide has been used as a catalyst to promote the oxidation of dye in the presence of H2O2. However, the facile separation of manganese oxide from the treated water is still an open question. In order to accomplish a facile recovery, a simple two-step process, hydrolysis and oxidation–reduction, was adopted to immobilize in-situ generated amorphous manganese oxide on polymer fiber in this work. Due to the synergistic effect of manganese oxide and polymer matrix, along with the swelling response of fiber to water stimulus, the obtained catalyst was found to have higher catalytic activity for dye oxidation than single manganese oxide or fiber. When 0.072 g of catalyst and 0.05 mL of H2O2 were added in 10 mL of aqueous solution of cation blue with the concentration of 20 mg/L, the catalyst could be repeatedly used up to 10 cycles without any significant loss in its catalytic activity. The time that was needed for removing 90% of cation blue from its solution was less than 6 min during each cycle, and the removal efficiency of cation blue obtained at 10 min was up to 95%. The catalyst could accelerate the transformation of H2O2 into oxidative species such as HO∙, HOO∙, O2∙− and 1O2 in the presence of H2O, and the strong oxidizability of the oxidative species resulted in the rapid removal of cation blue.

Chemical Resolution of C,N-Unprotected α-Substituted β-Amino Acids Using Stable and Recyclable Proline-Derived Chiral Ligands

We report the first purely chemical method for the resolution of C, N-unprotected racemic α-substituted β-amino acids (β2-AAs) using thermodynamically stable and recyclable chiral proline-derived ligands. The ligands and racemic β2-AAs along with Ni(II) could form a pair of Ni(II) complex diastereoisomers with a desirable diastereoselectivity (dr up to 91:9). Enantiomerically pure C, N-unprotected β2-AAs could be obtained by simple hydrolysis of an isolated favored Ni(II) complex. The method featured unique versatility compared with enzymatic approaches and characterized by its broad synthetic generality, good stereochemical outcome, and mild reaction conditions, thus making it a powerful supplement in the field of chemical resolution of β2-AAs.

Cellulose-polyethyleneimine blend membranes with anomalous nanofiltration performance

A unique method for the preparation of cellulose-polyethyleneimine (PEI) blend membranes for nanofiltration is presented. Trimethylsilyl cellulose was used as a precursor for the blend membrane fabrication followed by a simple hydrolysis to regenerate the cellulose structure. The resulting homogeneous blend membranes exhibited high neutral solute rejection in water, which was surprisingly better than the performance of the individual membranes due to the strong interactions between the blended polymers. More interestingly, the same membrane demonstrated over five times higher flux of methanol after solvent activation with water as compared to the fluxes of the pure membranes, attributed to formation of nanocracks. High rejection of negatively charged dyes in this solvent with around 450 Da molecular weight cut-off was obtained at an exceptionally high flux of 160 Lm−2 h−1 at a pressure of 4.5 bar. The membranes will be beneficial in nanofiltration of polar solvents containing neutral and charged molecules.

In situ growth of β-FeOOH on hierarchically porous carbon as anodes for high-performance lithium-ion batteries

Sugarcane bagasse, a waste product of the sugarcane industry can be used as a precursor for the preparation of carbon. In this study, a composite consisting of hierarchically functionalized porous carbon (FPC) and β-FeOOH was synthesized via a simple and effective hydrolysis method. The hydrothermal process before the carbonization and activation of the bagasse maintained the hierarchical interconnected porous structure of the sugarcane bagasse. A nitric acid (HNO3) functionalization treatment enabled an in-situ growth of β-FeOOH on the hierarchically structured bagasse. When tested as an anode for lithium-ion batteries, the obtained FPC/β-FeOOH composite showed a high discharge capacity of 898.8 mAh g−1 at 0.2 A g−1 after 350 cycles and achieved a specific capacity of 446.1 mAh g−1 at a current rate of 1 A g−1 after 1000 cycles together with a remarkable coulombic efficiency of 99.9%. This excellent electrochemical performance of the FPC/β-FeOOH composite can be attributed to the synergistic effect of the interconnected porous structure of porous carbon and the electrochemically active tunnel type β-FeOOH nanorods. The strategy developed here is promising in design and fabrication of other composites having interconnected porous structures with high performance.

Synthesis of 2,3-Difunctionalized Benzofuran Derivatives through Palladium-Catalyzed Double Isocyanide Insertion Reaction.

A novel palladium-catalyzed tandem cyclization of 1-(allyloxy)-2-ethynylbenzene derivatives with isocyanides in the presence of water has been developed. The key intermediates, benzofuran-3-α-carbonyl aldehydes, were obtained through a simple acid hydrolysis process and could serve as precursors for structurally diverse 2,3-difunctionalized benzofuran derivatives such as important 2-benzofurylquinoxalines, benzofuran-3-α-ketoesters and benzofuryl ynediones. This transformation features convenient operation, simple and commercially available starting materials, broad functional-group compatibility, and moderate to good reaction yields.

High Aspect Ratio Carboxylated Cellulose Nanofibers Cross-linked to Robust Aerogels for Superabsorption-Flocculants: Paving Way from Nanoscale to Macroscale.

Charged nanocellulose (NC) with a high aspect ratio (larger than 100) extracted from animal or bacterial cellulose and chemical cross-linked NC aerogels have great promising applicability in material science, but facile fabrication of such NC aerogels from plant cellulose by physical cross-linking still remains a major challenge. In this work, carboxylated cellulose nanofiber (CNF) with the highest aspect ratio of 144 was extracted from wasted ginger fibers by a simple one-step acid hydrolysis. Our approach could easily make the carboxylated CNF assemble into robust bulk aerogels with tunable densities and desirable shapes on a large scale (3D macropores to mesopores) by hydrogen bonds. Excitingly, these CNF aerogels had better compression mechanical properties (99.5 kPa at 80% strain) and high shape recovery. Moreover, the CNF aerogels had strong coagulation-flocculation ability (87.1%), removal efficiency of MB dye uptake (127.73 mg/g), and moderate Cu2+ absorption capacity (45.053 mg/g), which were due to assistance mechanisms of charge neutralization, network capture effect, and chain bridging of high aspect ratio carboxylated CNF. This provided a novel physical cross-linking method to design robust aerogels with modulated networked structures to be a general substrate material for industrial applications such as superabsorbent, flocculation, oil-water separation, and potential electrical energy storage materials.

Organogel Polymers from 10-Undecenoic Acid and Poly(vinyl acetate)

Organogels are used in a variety of high value applications including the removal of toxic solvents from aqueous environments and the time-controlled release of compounds. One of the most promising gelators is a polyvinyl polymer containing medium chain length carboxylic acids. The existing production of this product requires synthesis of vinyl esters containing medium length carboxylic chains. This starting material must be made from an expensive and low yielding transvinylation reaction, which leaves production of useful vinyl esters and, as a result, the organogels themselves, outside the realm of practical chemistry. We have developed a new, more practical production process and used it to directly synthesize a new polymer. This new process utilizes commercially available polyvinyl acetate and accomplishes the transformation with simple hydrolysis and anhydride addition steps. The new polymers form organogels with chloroform, acetone or toluene with swell ratios up to 30. They also show time-controlled release of crystal violet over a 100 h span. This new production process opens the possibility of producing organogels utilizing agricultural resources.

Eosin-Y sensitized core-shell TiO2-ZnO nano-structured photoanodes for dye-sensitized solar cell applications

In the current investigation, TiO2 and TiO2-ZnO (core-shell) spherical nanoparticles were synthesized by simple combined hydrolysis and refluxing method. A TiO2 core nanomaterial on the shell material of ZnO was synthesized by utilizing variable ratios of ZnO. The structural characterization of TiO2-ZnO core/shell nanoparticles were done by XRD analysis. The spherical structured morphology of the TiO2-ZnO has been confirmed through field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) studies. The UV–visible spectra of TiO2-ZnO nanostructures were also compared with the pristine TiO2 to investigate the shift of wavelength. The TiO2-ZnO core/shell nanoparticles at the interface efficiently collect the photogenarated electrons from ZnO and also ZnO act a barrier for reduced charge recombination of electrolyte and dye-nanoparticles interface. This combination improved the light absorption which induced the charge transfer ability and dye loading capacity of core-shell nanoparticles. An enhancement in the short circuit current (Jsc) from 1.67 mA/cm2 to 2.1 mA/cm2 has been observed for TiO2-ZnObased photoanode (with platinum free counter electrode), promises an improvement in the energy conversion efficiency by 57% in comparison with that of the DSSCs based on the pristine TiO2. Henceforth, TiO2-ZnO photoelectrode in ZnO will effectively act as barrier at the interface of TiO2-ZnO and TiO2, ensuring the potential for DSSC application.

Fe-TiO2 and Fe2O3 quantum dots co-loaded on MCM-41 for removing aqueous rose bengal by combined adsorption/photocatalysis

Adsorption and photodegradation are promising approaches for removing organic pollutions. In this study, we combined these two processes by co-loading Fe-TiO2 and Fe2O3 quantum dots (QDs) on porous MCM-41, using a simple hydrolysis method. X-ray diffraction, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy results indicated that Fe-TiO2 QDs are formed at low Fe precursor concentrations, while additional Fe2O3 QDs are formed at higher Fe precursor concentrations. The Fe2O3 and Fe-TiO2 QDs impart high adsorption capacity and high photoactivity to the porous MCM-41, respectively. Thus, their combination results in a synergic effect of the adsorption and photodegradation. The highest-performing sample exhibits excellent performance in removing rose bengal from aqueous solution.