Influences of the Reaction Temperature and Catalysts on the Pyrolysis Product Distribution of Lignocellulosic Biomass (Aspen Wood and Rice Husk).

It is important to clarify the distribution of pyrolysis products from lignocellulosic biomass for its thermal transformation to produce high-quality bio-oil. Influences of the reaction temperature and catalysts on the pyrolysis product distribution from aspen wood (AW) and rice husk (RH) were studied by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). The difference in components from the lignocellulosic biomass results in different pyrolysis characteristics of the biomass raw materials. The reaction temperature significantly influences the product distribution from AW and RH pyrolysis. In all AW catalysis experiments, acids (8.35%), ketones (3.79%), phenols (4.73%), and esters (1.50%) have the lowest content while carbohydrates (48.75%) demonstrate the highest content when taking zinc chloride (ZnCl2) as the catalyst; the HZSM-5 molecular sieve (HZSM-5) promotes the generation of esters (7.97%) and N-compounds (22.43%) while inhibiting production of aldehydes (2.41%); addition of an MCM-41 molecular sieve (MCM-41) is conducive to increasing the contents of aldehydes (21.29%), furans (5.88%), ketones (22.30%), acids (20.46%), and hydrocarbons (4.85%), while reducing the contents of alcohols (0) and carbohydrates (0). In all RH catalysis experiments, the addition of ZnCl2 helps increase the content of carbohydrates (39.16%) and decrease the contents of ketones (3.89%), phenols (5.20%), alcohols (2.34%), esters (1.13%), and N-compounds (3.09%); when applying HZSM-5 as the catalyst, hydrocarbons (18.28%) and alcohols (6.66%) reach their highest content while acids (13.21%) have the lowest content; MCM-41 promotes the generation of aldehydes (25.33%) and furans (5.55%) while inhibiting that of carbohydrates (1.42%).

Effect of Reaction Temperature on the Microstructure and Properties of Magnesium Phosphate Chemical Conversion Coatings on Titanium.

Magnesium phosphate (MgP) has garnered growing interest in hard tissue replacement processes due to having similar biological characteristics to calcium phosphate (CaP). In this study, an MgP coating with the newberyite (MgHPO4·3H2O) was prepared on the surface of pure titanium (Ti) using the phosphate chemical conversion (PCC) method. The influence of reaction temperature on the phase composition, microstructure, and properties of coatings was systematically researched with the use of an X-ray diffractometer (XRD), a scanning electron microscope (SEM), a laser scanning confocal microscope (LSCM), a contact angle goniometer, and a tensile testing machine. The formation mechanism of MgP coating on Ti was also explored. In addition, the corrosion resistance of the coatings on Ti was researched by assessing the electrochemical behavior in 0.9% NaCl solution using an electrochemical workstation. The results showed that temperature did not obviously affect the phase composition of the MgP coatings, but affected the growth and nucleation of newberyite crystals. In addition, an increase in reaction temperature had a great impact on properties including surface roughness, thickness, bonding strength, and corrosion resistance. Higher reaction temperatures resulted in more continuous MgP, larger grain size, higher density, and better corrosion resistance.

Quantifying the Contribution of Hot Electrons in Photothermal Catalysis: A Case Study of Ammonia Synthesis over Carbon-supported Ru Catalyst.

Photothermal catalysis is one of the most promising green catalytic technologies, while distinguishing the effects of hot electrons and local heating remains challenging. Herein, we reported that the actual reaction temperature of photothermal ammonia synthesis over carbon-supported Ru catalyst can be measured based on Le Chatelier's principle, enabling the hot-electron contribution to be quantified. By excluding local heating effects, we established that the activation energy via photothermal catalysis was much lower than that of thermocatalysis (54.9 vs. 126.0 kJ mol-1 ), stemming from hot-electron injection lowering the energy barriers for both N2 dissociation and intermediates hydrogenation. Furthermore, hot-electron injection acted to suppress carbon support methanation, giving the catalyst outstanding operational stability over 1000 h. This work provides new insights into the hot-electron effects in ammonia synthesis, guiding the design of high-performance photothermal catalysts.

The potential meat flavoring generated from Maillard reaction products of wheat gluten protein hydrolysates-xylose: Impacts of different thermal treatment temperatures on flavor.

Wheat gluten protein hydrolysates were prepared by Flavourzyme, followed by xylose-induced Maillard reaction at different temperatures (80 °C, 100 °C and 120 °C). The MRPs were subjected to analysis of physicochemical characteristics, taste profile and volatile compounds. The results demonstrated that UV absorption and fluorescence intensity of MRPs significantly increased at 120 °C, suggesting formation of a large amount of Maillard reaction intermediates. Thermal degradation and cross-linking simultaneously occurred during Maillard reaction, while thermal degradation of MRPs played a more predominant role at 120 °C. MRPs exhibited high umami and low bitter taste at 120 °C, accompanied by the high content of umami amino acids and low content of bitter amino acids. Furans and furanthiols with pronounced meaty flavor served as the main volatile compounds in MRPs at 120 °C. Overall, high temperature-induced Maillard reaction of wheat gluten protein hydrolysates and xylose is a promising strategy for the generation of potential plant-based meat flavoring.

Effect of Reaction Temperature on Properties of Torrefied Kenaf.

Torrefaction is a thermal treatment method used to achieve solid-phase biofuel. Raw biomass generally have low heating value and high moisture content; thus, these characteristics should be enhanced before using it as a fuel. In this study, herbaceous biomass kenaf was torrefied at 220, 260, 300, and 340 °C under nitrogen atmosphere for 30 min to investigate the effect of temperature on its properties. The properties of torrefied kenaf were classified into two groups: physical properties such as mass and energy yields, moisture content, and proximate analysis and chemical properties such as functional groups and chemical compositions of sugars and lignin. The mass and energy yield of torrefied kenaf decreased as the reaction temperature increased. In addition, an increase in carbon content and a rapid decrease in oxygen content were observed in torrefied kenaf, which indicated the degradation of compounds such as hemicellulose and cellulose. Elemental analysis, proximate analysis, thermal analysis, Fourier transform infrared spectroscopy, and chemical composition analysis were performed to further investigate the characteristics of torrefied kenaf.

Modification of Ovalbumin by Maillard Reaction: Effect of Heating Temperature and Different Monosaccharides.

Glycosylation is considered to be an effective way to improve the performance of protein emulsification. This study focused on the effects of the molecular structure and emulsifying properties of ovalbumin (OVA) by wet heating Maillard reaction with three types of monosaccharides (i.e., xylose, glucose, and galactose). Results showed that increasing reaction temperature from 55°C to 95°C could significantly improve the degree of grafting (DG), while glycosylated OVA conjugate with xylose at 95°C processed the highest DG of 28.46%. This reaction was further confirmed by the browning intensity determination. Analysis of Fourier transform infrared spectrophotometer, circular dichroism, and fluorescence spectra indicated that there were slight changes in the subunits and the conversion of α-helices to ß-sheets, as well as the unfolded structures, thereby increasing the surface hydrophobicity and absolute zeta potential of obtained glycosylated OVA. Glycosylation endowed OVA with better emulsifying properties, especially the xylose glycosylated OVA was superior to that of glucose and galactose glycosylated OVA, which was mainly due to its shorter molecular chains with smaller steric hindrance for reaction. Furthermore, the enhancement of emulsifying properties may be attributed to the synergistic effect of stronger electrostatic repulsion of larger absolute zeta potential and the steric hindrance from thicker adsorbed layer, thereby inhibiting aggregation and flocculation of emulsion droplet.

Glycerol Electrocatalytic Reduction Using an Activated Carbon Composite Electrode: Understanding the Reaction Mechanisms and an Optimization Study.

The conversion of biomass-derived glycerol into valuable products is an alternative strategy for alleviating energy scarcity and environmental issues. The authors recently uncovered an activated carbon composite electrode with an Amberlyst-15 mediator able to generate 1,2-propanediol, diethylene glycol, and acetol via a glycerol electrocatalytic reduction. However, less attention to mechanistic insights makes its application to industrial processes challenging. Herein, two proposed intermediates, acetol and ethylene glycol, were employed as the feedstocks to fill the gap in the mechanistic understanding of the reactions. The results discovered the importance of acetol in producing 1,2-propanediol and concluded the glycerol electrocatalytic reduction process has a two-step reduction pathway, where glycerol was initially reduced to acetol and consecutively hydrogenated to 1,2-propanediol. At 353 K and 0.28 A/cm2, 1,2-propanediol selectivity achieved 77% (with 59.8 C mol% yield) after 7 h of acetol (3.0 mol/L) electrolysis. Finally, the influences of the temperature, glycerol initial concentration, and current density on the glycerol electrocatalytic reduction were evaluated. The initial step involved the C-O and C-C bonds cleavage in glycerol plays a crucial role in producing either acetol or ethylene glycol intermediate. This was controlled by the temperature, which low to moderate value is needed to maintain a selective acetol-1,2-propanediol route. Additionally, medium glycerol initial concentration reduced the hydrogen formation and indirectly improved 1,2-propanediol yield. A mild current density raised the conversion rate and minimized the growth of intermediates. At 353 K and 0.21 A/cm2, glycerol (3.0 mol/L) electrocatalytic reduction to 1,2-propanediol reached the maximum yield of 42.3 C mol%.

The Influence of Residuals Combining Temperature and Reaction Time on Calcium Phosphate Transformation in a Precipitation Process.

Precipitation is one of the most common processes to synthesize hydroxyapatite, which is the human body's mineral forming bone and teeth, and the golden bioceramic material for bone repair. Generally, the washing step is important in the precipitation method to remove the residuals in solution and to stabilize the phase transformation. However, the influence of residuals in combination with the reaction temperature and time, on calcium phosphate formation, is not well studied. This could help us with a better understanding of the typical synthesis process. We used a fixed starting ion concentration and pH in our study and did not adjust it during the reaction. XRD, FTIR, ICP-OES, and SEM have been used to analyze the samples. The results showed that combining residuals with both reaction temperature and time can significantly influence calcium phosphate formation and transformation. Dicalcium phosphate dihydrate formation and transformation are sensitive to temperature. Increasing temperature (60 °C) can inhibit the formation of acidic calcium phosphate or transform it to other phases, and further the particle size. It was also observed that high reaction temperature (60 °C) results in higher precipitation efficiency than room temperature. A low ion concentration combining reaction temperature and time could still significantly influence the calcium phosphate transformation during the drying.

Elevated CO-free hydrogen productivity through ethanol steam reforming using cubic Co-Nanoparticles based MgO catalyst.

Hydrogen production through the processes of ethanol catalytic steam reforming (SR) is one of the promising routes due to its extensive yield that can be gained. However, catalyst deactivation (as a result of coke formation) is a major drawback in such a process. Therefore, this research work introduces efficient MgO supported Cubic cobalt oxide catalyst for the process of ethanol SR. This catalyst was successfully able to produce gases that have high contents of CO-free hydrogen was produced (above 78%) at 500°C and various flow rates of feed. This catalyst had also avoided coke formation at that temperature while attaining capture of the in-situ produced CO2 gas. The employment of an operating temperature beyond 500°C, during the SR process, could reduce the percentages of hydrogen (in products) to less than 55%. Such increases in the operational temperature could leave behind the detection of coke deposits onto the catalyst surface. The presence of these deposits was confirmed visually as well as via Raman spectroscopy.

Direct Gas-Phase Oxidation of Propylene to Acetone in the Presence of H2 and O2 over Au/TS-1 Catalyst.

A novel process for the preparation of acetone is reported by gas-phase oxidation of propylene in the presence of H2 and O2 with Au supported TS-1 catalyst (Au/TS-1). By elevating the reaction temperature to 280°C, Au/TS-1 catalyzes 11.6% propylene generating acetone with 70.6% selectivity, and 8.2% acetone in onepass yield. Acetone is originated from propylene oxide isomerization, which is mainly attributed to the surface of the Lewis base and high reaction temperature. Furthermore, small Au nanoparticle size promotes the reaction.

Removal of Cr(VI) with nano-FeS and CMC-FeS and transport properties in porous media.

We investigated the effect of CMC dosage on dispersibility and sedimentation of FeS, and the effects of initial Cr(VI) concentrations, reaction temperatures and initial pH values on the Cr(VI) removal by Nano-FeS and CMC-FeS through experiments. At the same time, the migration performance and deposition of Nano-FeS and CMC-FeS under different conditions were investigated. The results showed that: Nano-FeS aggregated to floc and precipitated. The 2.4% CMC-FeS had good dispersibility and anti-settling capacity. With the initial concentration of Cr(VI) increased from 10 to 50 mg L-1, the Cr(VI) removal efficiencies of Nano-FeS and CMC-FeS decreased. CMC prolonged reaction time between FeS and Cr(VI). When the reaction temperature increased from 10°C to 25°C, and the promotion of Cr(VI) reduction by CMC-FeS was higher than that of Nano-FeS. When the initial pH was 3-9, the Cr(VI) removal efficiencies of Nano-FeS and CMC-FeS were almost similar. But Cr(VI) removal by CMC-FeS was significantly higher than by Nano-FeS 23% at pH 12, which indicated that CMC-FeS still had high removal ability for Cr(VI) at high pH. From the breakthrough curves, the penetration ability (Ci /C 0) of the two kinds of FeS nanoparticles in coarse, medium and fine sand was CMC-FeS > Nano-FeS. The maximum transport distance (L max) of CMC-FeS was 6.4 times longer than that of Nano-FeS in medium sand. The increase of FeS injection concentration resulted in more FeS deposition into the media, but the CMC modification could significantly reduce the deposition rate (k) and amount of deposition.

Dataset on the effect of the reaction temperature during spray pyrolysis for the synthesis of the hierarchical yolk-shell CNT-(NiCo)O/C microspheres.

The data presented in this article are related to the research article entitled "Hierarchical yolk-shell CNT-(NiCo)O_C microspheres prepared by one-pot spray pyrolysis as anodes in lithium-ion batteries" (Oh et al., 2019). The data presented in this manuscript showed the effect of the reaction temperature during spray pyrolysis on the obtained microspheres morphology. Each morphology and phase of the microspheres obtained after spray pyrolysis were investigated.

Preparation of Graphite Oxide Containing Different Oxygen-Containing Functional Groups and the Study of Ammonia Gas Sensitivity.

A series of graphite oxide samples were prepared using the modified Hummers method. Flake graphite was used as the raw material and the reaction temperature of the aqueous solution was changed (0 °C, 30 °C, 50 °C, 60 °C, 70 °C, 80 °C, and 100 °C). X-ray diffraction, Fourier-transform infrared spectroscopy, Raman spectral analysis, X-ray photoelectron spectroscopy, and contact angle tests were performed to characterize the structure, chemical bonding, type, and content of oxygen-containing functional groups of the graphite oxide samples. The results showed that the type and content of each oxygen-containing functional group could be controlled by changing the reaction temperature with the addition of water. As the temperature of the system increased, the degree of oxidation of the graphite oxide samples first increased and then decreased. Too high a temperature (100 °C) of the system led to the formation of epoxy groups by the decomposition of some hydroxyl groups in the samples, causing the reduction of oxygen-containing functional groups between the graphite layers, poor hydrophilic properties, and low moisture content. When the system temperature was 50 °C, the interlayer spacing of the graphite oxide samples was at its highest, the graphite was completely oxidized (C/O = 1.85), and the oxygen-containing functional groups were mainly composed of hydroxyl groups (accounting for approximately 28.88% of the total oxygen-containing functional groups). The high content of hydroxyl and carboxyl groups had good hydrophilic ability and showed the highest moisture content. The sample at 50 °C had better sensitivity to ammonia because of its high hydroxyl group and carboxyl group content, with the sample showing an excellent profile when the ammonia concentration was 20⁻60 ppm.

Temperature dependent photocatalysis of g-C3N4, TiO2 and ZnO: Differences in photoactive mechanism.

Photocatalysis has been believed as one of the green and sustainable avenues to address energy and environmental crises by converting solar energy to chemical energy via reactions. Temperature is usually a vital factor controlling kinetics and thermodynamics of a reaction, but it has been less investigated in photocatalysis. In this work, the effect of reaction temperature on photocatalysis was investigated in a simple process, photocatalytic degradation of Congo Red (CR) on three typical catalysts, g-C3N4, TiO2 and ZnO, to differentiate the interfacial radical generation and reaction mechanism. The results showed that the temperature has a positive effect on the photocatalytic activity of the three catalysts. The scavenger experiments at various temperatures indicated that the generation of reactive species from the three photocatalysts is different and that the free radicals can be produced more quickly at higher temperatures, causing improved activities in photocatalysis. However, photocurrent analysis and EIS at various temperatures showed that the temperature had a different effect on recombination rate and transfer barriers of the charge carriers from each catalyst. Therefore, the dramatic enhancement in photodegradation activities probably originated from a novel mechanism of the photothermocatalytic oxidation. The interfacial reaction and mechanism from the influence of reaction temperature on the photocatalytic process was proposed.

Bio-oil production from hydrothermal liquefaction of Pteris vittata L.: Effects of operating temperatures and energy recovery.

Hyper-accumulator biomass, Pteris vittata L., was hydrothermally converted into bio-oils via hydrothermal liquefaction (HTL) in sub-supercritical water. The distributions and characterizations of various products as well as energy recovery under different temperatures (250-390 °C) were investigated. The highest bio-oil yield of 16.88% was obtained at 350 °C with the hydrothermal conversion of 61.79%, where the bio-oil was dominated by alcohols, esters, phenols, ketones and acidic compounds. The higher heating values of bio-oil were in the range of 19.93-35.45 MJ/kg with a H/C ratio of 1.26-1.46, illustrating its high energy density and potential for use as an ideal liquid fuel. The main gaseous products were CO2, H2, CO, and CH4 with the H2 yield peaking at 22.94%. The total energy recovery from bio-oils and solid residues fell within the range of 37.72-45.10%, highlighting the potential of HTL to convert hyper-accumulator biomass into valuable fuels with high conversion efficiency.

Rapid synthesis of platinum-ruthenium bimetallic nanoparticles dispersed on carbon support as improved electrocatalysts for ethanol oxidation.

Bimetallic nanocatalysts with small particle size benefit from markedly enhanced electrocatalytic activity and stability during small molecule oxidation. Herein, we report a facile method to synthesize binary Pt-Ru nanoparticles dispersed on a carbon support at an optimum temperature. Because of its monodispersed nanostructure, synergistic effects were observed between Pt and Ru and the PtRu/C electrocatalysts showed remarkably enhanced electrocatalytic activity towards ethanol oxidation. The peak current density of the Pt1Ru1/C electrocatalyst is 3731 mA mg-1, which is 9.3 times higher than that of commercial Pt/C (401 mA mg-1). Furthermore, the synthesized Pt1Ru1/C catalyst exhibited higher stability during ethanol oxidation in an alkaline medium and maintained a significantly higher current density after successive cyclic voltammograms (CVs) of 500 cycles than commercial Pt/C. Our work highlights the significance of the reaction temperature during electrocatalyst synthesis, leading to enhanced catalytic performance towards ethanol oxidation. The Pt1Ru1/C electrocatalyst has great potential for application in direct ethanol fuel cells.

Synthesis of varisized chitosan-selenium nanocomposites through heating treatment and evaluation of their antioxidant properties.

Varisized chitosan-selenium (CS-Se) nanocomposites were synthesized through an innovative method. It is the first time to use CS both as reductant and stabilizer to synthesize selenium nanoparticles (SeNPs). By manipulating the temperature, the well-dispersed CS-Se nanocomposites were synthesized via a simple one pot reaction with the size ranging from 83 to 208nm before being characterized by TEM, DLS, UV-vis, FTIR, XRD and TG analyses. The results showed that SeO32- was reduced to a stable SeNPs colloid at a comparatively high temperature, the amino group and hydroxyl group of CS were conjugated to the surface of SeNPs. Besides, the antioxidant activities of CS-Se nanocomposites were investigated by DPPH, ABTS+, hydroxyl radical, metal ion chelating and reducing power assays, which proved to be concentration-dependent, size-dependent and exhibited good antioxidant activities. The results suggested that CS-Se nanocomposites might be considered as a more appropriate selenium-adding form to achieve antioxidative goals in food.

Optimization of the conditions for the synthetic preparation of iron sucrose complex by response surface methodology / 国际药学研究杂志

Objective To optimize the conditions for the synthetic process of iron sucrose complex (ISC), via the investigation of the effects of reaction temperature (X1), reaction time (X2), amount of alkali (X3), and amount of sucrose (X4) on the relative molecular mass of the ISC product. Methods According to the experimental results for the single factor, the conditions dealing with the X1, X2, X3, and X4 parameters for the preparation of ISC were optimized by the Box-Behnker design combined with the response surface methodology using the weight average relative molecular mass of ISC as an indicator, and analyzed with gel permeation chromatography. Results The reaction temperature and the amount of alkali had a significant effect on the weight average relative molecular mass of ISC. The influence of the four factors in the descending order was as follows:X3＞X1＞X2＞X4. In the designed experimental conditions, theresponsevaluedecreasedwiththeincreaseofbothreactiontemperaturesandalkaliamounts. Conclusion Theresponse surface methodology could provide the relationship between the response values and variables via the minimum number experiments to obtain the optimized conditions for the preparation of ISCs.

Studies on effect of temperature on synthesis of hierarchical TiO2 nanostructures by surfactant free single step hydrothermal route and its photoelectrochemical characterizations.

Exotic hierarchical rutile TiO2 nanostructures are synthesized by surfactant free single step hydrothermal route. The effect of reaction temperature, ranging from 140°C to 200°C on the properties of the synthesized rutile-TiO2 is investigated. The synthesized rutile-TiO2 nanostructures are characterized using X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, UV-vis spectroscopy and scanning electron microscopy techniques. The deposited TiO2 samples are found to be photoelectrochemically active and the best photoelectrochemical performance (0.95±0.05%) is obtained for the sample deposited at 180°C. A possible temperature dependent growth mechanism resulting in photochemically active TiO2 nanostructure thin films is proposed.

Understanding temperatures and pressures during short radiochemical reactions.

Automated radiosynthesizers are critical for the reliable, routine production of PET tracers. To perform reactions in these systems, the temperature of the reactor heater is controlled, and the liquid temperature within the reaction vessel is presumed to closely follow. In reality, the liquid temperature can lag by several minutes and generally does not reach the heater temperature. Furthermore, because different synthesizers have different heating mechanisms and geometries, discrepancies are certain to exist between the actual temperatures experienced by the reaction mixture on different synthesizers. For dissimilar reactors, this can necessitate re-optimization of conditions when adapting a synthesis from one system to another, especially for the short-duration reactions common in radiochemistry. Herein, we study the relationship between the temperatures of the reactor heater and reaction liquid for various solvents using the ELIXYS radiosynthesizer as a representative example of a vial-based system. Our aims are to quantitatively illustrate this discrepancy to the community and provide data necessary to enable efficient translation of protocols between other radiosynthesizers and the ELIXYS.