Conversion Values Research Articles

Risk factors and predictive models in the progression from MCI to Alzheimer's disease.

The conversion of mild cognitive impairment (MCI) to Alzheimer's disease (AD) is related to various factors. The causal relationships among these factors remain unclear. This study aims to investigate pathways of the progression by using causal analysis and build a predictive model with high accuracy. 162 MCI patients were recruited from the Alzheimer's Disease Neuroimaging Initiative database. 68 patients progressed to AD. 94 patients did not convert to AD. We captured standard T1-weighted images, processed them for feature extraction, and selected relevant features using mRMR and LASSO to calculate cortical and nuclear scores. The computational causal structure discovery and regression analyses were adopted to analyze the intricate relationships among APOE ε4 alleles, P-tau, Aβ1-42, cortical and nuclear scores. The individualized prediction nomogram was constructed. Our results indicated that APOE ε4 alleles was the promoter that caused MCI to transform into AD. Three independent pathways were identified, including P-tau, Aβ1-42, and cortical atrophy. P-tau was the cause of nuclear atrophy. The APOE ε4 alleles, P-tau, Aβ1-42, cortical and nuclear scores all had good predictive value for the MCI conversion. The predictive accuracy of the combined model was the highest, with an AUC of 0.918 in the training cohort and 0.908 in the testing cohort. A multi-predictor nomogram was established. Our study elucidated the initiating factors and three independent pathways involved in the conversion of MCI to AD. The predictive value of each factor was clarified and a multi-predictor nomogram was established with high accuracy.

Complete replacement of fishmeal with unconventional animal protein sources: A comparative study of the effects of use of mealworm, earthworm and zooplankton on growth parameters, fatty acid composition and sensory profile rainbow trout

The global trend in aquaculture is to replace fishmeal with an alternative and sustainable source of protein for fish farming. As a result, some species of invertebrates have found a place in aquaculture as a rich source of protein and a promising substitute for fishmeal. This study aimed to investigate the effects of alternative protein sources on the growth parameters of rainbow trout (Oncorhynchus mykiss) as well as the fatty acid profile and the sensory quality of the fish fillets. The gas chromatography technique with a flame ionization detector was used to determine the fatty acid composition of the rainbow trout fillets, while different equations were used to determine the growth parameters and the hepatosomatic index. The sensory evaluation of the rainbow trout fillet was determined by a descriptive sensory analysis, a quality assessment and a consumer acceptance test. The replacement of fishmeal by mealworms (MWD) and earthworms (EWD) resulted in a positive effect on growth parameters, feed conversion, and hepatosomatic index (HSI) values. The mortallity of the rainbow trout fed with the experimental diets was less than 28 %. The eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) content of the trout fillets decreased with the inclusion of MWD (1.34 and 5.20 %, respectively) and EWD (1.74 and 6.41 %, respectively) in the trout diet. Feeding rainbow trout with MWD and EWD caused a decrease in the n-3/n-6 ratio compared to FMD (0.32 and 0.34, respectively vs. 0.56), whereas the addition of ZOD resulted in the increase of the n-3/n-6 ratio (0.67). The samples of fillets of trout fed with MWD and EWD belonged to the "very good" level of average sensory quality, while the fillets of trout fed with zooplankton were in the "good" quality range. Regarding acceptability by consumers all rainbow trout fillets shown good consumer acceptance.

CO2 Hydrogenation to Methanol over In2O3 Decorated by Metals of the Iron Triad.

The growing concentration of CO2 in the atmosphere is a serious problem, and efforts to counter this issue are thus highly important. One of the possible approaches to solving this problem is the conversion of waste CO2 into products with added economic value. Methanol is one of these products with vast potential usage. In this study, indium oxide prepared by a simple precipitation method and modified by nanoparticles of metals from the iron triad were tested as possible catalysts to produce methanol by the method of CO2 hydrogenation. The prepared catalysts demonstrated a strong dependence of their catalytic activity on used metal. The best selectivity for the production of CH3OH was observed for the Fe/In2O3 catalyst at the value of 54.7% at 300 °C. However, due to the higher value of CO2 conversion, the highest CH3OH formation rate was observed at a value of 11.3 mmol/(h*g) at 300 °C for a composite of Ni/In2O3.

Evaluation study of solar powered public street lighting as battery charging at Islamic Center based on PSIM

Electrical energy is essential for the growth and advancement of technological knowledge that continues to increase. Solar cells are devices that convert solar energy through photovoltaic devices. Solar cell public street lighting (PJUBS) uses unlimited and free solar energy, is a feasible and cheap alternative to providing electric lighting. The Islamic center mosque is one of the places of worship for the majority of Muslims in the city of Lhokseumawe using public street lighting to support public security and safety. Installation of lamps for lighting is installed at several points, namely right, left or in the middle of the road, as needed, including flyovers, underpasses, and bridges. Public street lighting that is efficient and environmentally friendly is in accordance with SNI 7391: 2008. In this study, the lamps used in this evaluation study are solar types with a power of 50 Watts. The calculation results show that the illumination produced at the end of the road when using a 50 Watt solar LED lamp is 0.29 lux so that this does not comply with the provisions of BSN SNI 7391: 2008. This condition is influenced by several factors, namely surface temperature, shadows, inclination angle, light intensity, irradiation, and the condition of the panel surface in order to maximize the conversion value of sunlight into electrical energy

Optimization and modeling of biodiesel production from oleic acid in plug flow reactor

In recent years, biodiesel has been preferable to fossil fuels because of its renewability, biodegradability, and producibility from various wastes. In this study, the esterification reaction between oleic acid and methanol was carried out in the presence of sulfuric acid, which is a homogeneous acid catalyst, to produce biodiesel. Experiments were carried out in a plug flow reactor (PFR) and a batch reactor. The experimental conditions with the highest conversion obtained in the PFR were determined and applied to the batch reactor and results were compared. The effects of temperature (45, 55, 65 in Celsius), catalyst concentration (2%, 4%, 6% by weight), and methanol/oleic acid mole ratio (3, 6, 9) on oleic acid conversion were examined in the PFR. Retention times at different flow rates were calculated to determine the reaction time in the PFR and reactions were carried out between 2 and 6 minutes. In the reactions carried out in the PFR, the highest conversion value was obtained as 97.33% under conditions where the catalyst concentration was 6% by weight, the temperature value was 55oC and the alcohol/acid mole ratio was 6:1. These conditions were applied to the batch reactor and the conversion value was found to be 50%. When the experimental results were examined, it was seen that the effect of temperature and alcohol/acid ratio on the conversion was greater than the effect of the catalyst concentration on the conversion. The modeling of oleic acid/methanol esterification, i.e., biodiesel production, at specific boundary values was found to follow a cubic dependence in the general dependence equation via Response Surface Methodology.

Understanding the kinetics of waste plastic catalytic pyrolysis under microwave irradiation for enhanced resource valorization

The increasing accumulation of ABS plastic waste poses significant environmental challenges, necessitating efficient methods for its disposal and recycling. The pyrolysis of the ABS plastic waste was performed under various heating programs including constant heating rate (27.5, 42.2 and 65 K min−1), and sample-controlled reaction rate (0.01 min−1) to obtain the TG curves using the in-house developed microwave assisted thermogravimetric analyzer. Fe-impregnated SiC was used as thermal and chemical catalyst, while neat SiC played only thermal catalyst role. The modified Sestak-Bergren equation used to model the TG data by Pearson’s linear correlation and associated parameters n = 1.129 and m = 0.27 was achieved. The comparison of normalized form of the conversion function (f (α)/f (0.5)) with the most common models of solid-state reactions showed that random scission model (L2) was the most suitable approach to physically explain the pyrolysis of ABS plastic waste. Furthermore, by applying isoconversional kinetic analysis, the variation of activation energy (Eα) with conversion value was approximately constant. The Eα obtained was 140.5 and 63.7 kJ/mol with SiC and Fe/SiC, respectively. These findings hold practical implications for industrial applications or waste management strategies, particularly when considering the developed microwave-assisted real-time TGA-pyrolysis, which can enhance the efficiency and sustainability of plastic waste recycling processes.

Catalytic Biolubricant Production from Canola Oil Through Double Transesterification with Methanol and Neopentyl Glycol

In the current environmental scenario, the proposal of alternatives for petroleum-based products has considerably increased, with the aim of looking for bioproducts with interesting properties such as biodegradability, sustainability and efficiency, among others. In this sense, the role of biolubricants is promising, offering a wide range of possibilities through different methods and operating conditions. Specifically, double transesterification could be a suitable process in a biorefinery context. The aim of this work was to produce a biolubricant through double transesterification with methanol and neopentyl glycol (NPG) under different reaction conditions by using homogeneous catalysis (sodium methoxide). Different catalyst concentrations, among other changes in reaction conditions (temperature ranging between 100 and 140 °C and NPG/FAME ratios between 0.5 and 2), were used, obtaining high conversion values (96%) and a final product with a high viscosity (20.7 cSt), which allows for its use as engine oil (SAE 5W). In conclusion, biodiesel and biolubricant production was feasible through homogeneous catalysis, proving the feasibility of this process at the laboratory scale. Further studies, including the use of different heterogeneous catalysts, as well as the implementation of this process at a semi-industrial scale, are recommended.

Enhanced Gas-Phase pollutant removal using Pt nanoparticle-modified exfoliated carbon nitride photocatalysts under UV and visible light

Platinum nanoparticles (Pt NPs) have been prepared by the organometallic approach on the surface of exfoliated graphitic carbon nitride (exf-g-CN) with different metal loadings. Multi-technique characterization shows a good dispersion of Pt NPs on the surface of exf-g-CN with a narrow size distribution between 1.7–2.2 nm and a BET area of about 120 m2/g. The Pt NPs are mainly composed of platinum metal with a minor contribution of oxidic surface species. The effect of UV-A and Vis light of different wavelengths on the photocatalytic performance is investigated. The as-prepared hybrid materials show excellent photocatalytic activity for the decontamination of air from volatile organic compounds (VOCs, in particular trichloroethylene, C2HCl3) under low power visible light irradiation. The conversion value reaches a maximum close to 85 % at 405 nm Vis light for 0.5 wt.% Pt loading. At this level of Pt content, electron and hole recombination rates are suppressed according to photoluminescence analysis. Photonic efficiencies of around 0.3 % were achieved under Vis light. The optimised material shows high stability from 2,500 min of operation. XPS analysis suggests the crucial role of Pt/Pt2+ and chlorine species detected on used samples in the reaction rate and stability of the material.

COMPARISON OF BIODIESEL PRODUCTION FROM OLEIC ACID IN BATCH REACTOR AND MEMBRANE REACTOR

This study examines the production of biodiesel by the esterification reaction between oleic acid and ethanol. Conversions between reactions carried out with batch reactors and membrane reactors are compared and the advantages of membrane reactors are stated. The parameters examined in the study are catalyst concentration (2%, 4%, 6%), ethanol/oleic acid molar ratio (3,6,9) and temperature (between 45-65°C). The effect of these parameters on oleic acid conversion was evaluated and the reactions were carried out under the conditions determined because of the optimization. The highest conversion value in the batch reactor was obtained as 85.5% at 65°C, with an alcohol: acid molar feed ratio of 6:1 and a catalyst concentration of 4%. In addition, 50% conversion was achieved in the batch reactor with an ethanol/oleic acid molar ratio of 3, temperature 55°C and 4% catalyst ratio, while 75% conversion was achieved in the membrane reactor. These results show that the acid conversion achieved in the membrane reactor is 26% higher compared to batch reactors under the same operating conditions.

NiO Nano- and Microparticles Prepared by Solvothermal Method—Amazing Catalysts for CO2 Methanation

Nickel oxide (NiO) is one of the most popular hydrogenation catalysts. In heterogeneous catalysis, nickel oxide is used, for example, as a suitable methanation catalyst in the Fischer–Tropsch reaction not only for CO hydrogenation but also in the modified Fischer–Tropsch reaction with CO2. However, CH4 selectivity and CO2 conversion strongly depend on NiO micro- (MPs) and nanoparticles’ (NPs) shape, size, and surface area. In this study, the synthesis of NiO micro- and nanoparticles was conducted using the simple solvothermal method. Different morphologies (microspheres, sheet clusters, hexagonal microparticles, and nanodiscs) were prepared using this method with different solvents and stabilizers. The prepared catalysts were tested in the hydrogenation of CO2 in a gas phase with excellent conversion values and high selectivity to produce CH4. The best results were obtained with the NiO with disc or sphere morphology, which produced methane with selectivity at a level near 100% and conversion close to 90%.

Toward new applications of terpenes in polymeric materials: Synthesis and characterization of myrcene‐modified unsaturated polyester resins

Abstractβ‐Myrcene, a terpenic monomer, holds potential for developing sustainable polymer‐based materials with enhanced properties. This study examines the synthesis of a myrcene‐based monomer and its incorporation into unsaturated polyesters, focusing on polymerization, curing, and final properties. Unsaturated polyesters were synthesized with varying myrcene‐based monomer content (6, 12, and 24 mol%), phthalic anhydride, maleic anhydride, propylene glycol, ethylene glycol, and diethylene glycol. Polymerization achieved conversion values of 0.92–0.93, resulting in polyesters with molar masses between 1400 and 1700 g mol−1 and dispersity indices of 2.0 to 2.3. Nuclear magnetic resonance (1H NMR) demonstrated short branch formation in myrcene‐modified polyesters and a high maleate‐to‐fumarate isomerization rate (92.66%–95.7%), affecting carbon–carbon double bonds per polyester mole (2.27 to 4.28) and final resin performance. Rheological analysis in a styrene solution (70/30 wt%) indicated shear‐thinning behavior, with viscosities ranging from 0.59 to 3.8 Pa·s, suggesting branching affects chain entanglement. Differential scanning calorimetry (DSC) revealed decreased curing enthalpy with increasing myrcene content, and it was inferred that myrcene's double bonds did not participate in curing. Glass transition temperatures of cured polyesters (70–107 °C) correlate with enthalpy trends. Thermal stability of myrcene‐modified polyesters is similar to the reference polyester, highlighting myrcene's potential as a sustainable monomer for customizable unsaturated polyesters.

Analysis of Financial Fraud Based on the GONE TheoryA Case Study of Hangzhou Century Co., Ltd.

Convertible bonds allow creditors to convert their claims into company shares under certain conditions. Because of this debt-equity conversion feature, the issuance conditions, pricing and conversion value of convertible bonds are highly susceptible to financial information. Increasing the market value of a company's stock by exaggerating earnings or concealing debt may lead to convertible bond investment decisions based on misinformation, which in turn affects investors and the healthy operation of the market. Based on the GONE theory, this paper analyses the motivation of financial fraud in convertible bond documents and proposes corresponding preventive measures for its characteristics. Through the research and analysis of this type of financial forgery, the preventive governance of financial forgery can be further strengthened, which not only helps to protect the company's reputation and ensure the accuracy and reliability of the financial report, but also helps to attract and maintain the trust of investors, avoid possible legal risks and economic losses, and create a transparent and honest financial environment for the market to promote the efficiency of the market and the fair competition of enterprises.

Regulating V2O5 Layer Spacing by a Polyaniline Molecule Chain to Improve Electrochemical Performance in Salinity Gradient Energy Conversion.

Salinity gradient energy is a chemical potential energy between two solutions with different ionic concentrations, which is also an ocean energy at the junction of rivers and seas. In our original work, the device "activated carbon//(0.083 M Na2SO4, 0.5 M Na2SO4)//vanadium pentoxide" for the conversion of salinity gradient energy was designed, and the conversion value of 6.29 J g-1 was obtained. However, the low specific surface area of the original V2O5 inevitably resulted in limited active sites and slow ionic transport rates, and the inherent lower conductivity and narrower layer spacing of the original V2O5 also resulted in poor electrode kinetic performance and cycle stability, hindering its practical application. To solve the above problems, the present work provides a strategy of using polyaniline (PANI) molecule chain intercalation to regulate the layer spacing of the original V2O5, and through the expansion and traction of the layer spacing, the composite PANI/V2O5 (PVO) with high specific surface area is prepared and used as an anode material for electrochemical conversion of salinity gradient energy application. The significantly increased layer spacing of the crystal plane (001) corresponding to the original V2O5 was confirmed with the PANI by the hydrogen bonding and the van der Waals force. The high specific surface area of the composite provides more electrochemical active sites to realize a fast Na+ migration rate and high specific capacitance. Meanwhile, the inserted PANI molecule chain, which acts not only as a pillar enlarging the Na+ diffusion channel but also as an anchor locking the gap between V2O5 bilayers, improves the structural stability of the V2O5 electrode during the electrochemical conversion process. The proposed insertion strategy for the conductive polymer PANI has created a new way to improve the cycle stability performance of the salinity gradient energy conversion device.

Improved Photocatalytic Activity of Dion-Jacobson-Type Tantalate Perovskites Modified with FeCl2.

A rapid and feasible approach was used to develop visible-light-driven-type Dion-Jacobson perovskites by the modification of the RbLaTa2O7 host (RbLTO) with FeCl2 through the molten salt route. X-ray diffraction (XRD) characterization showed that FeCl2-modified layered perovskite (e.g., Fe@RbLTO) preserved its lamellar structure. SEM micrographs confirmed the layered morphology of both RbLTO and Fe@RbLTO perovskite materials. The UV-Vis spectra illustrated a significant red shift of the absorption edge after Fe2+ modification, with the band gap energy reducing from 3.88 to 1.82 eV. H2-TPR measurements emphasized the anchorage of Fe2+ species located on the surface of the layered perovskite as well as in the interlayer space. The synthesized materials were valorized as photocatalysts for the degradation of phenol under both Xe lamp and simulated solar irradiation (SSL) conditions. The photocatalytic reaction follows first-order kinetics. By-product formations during phenol (Ph) degradation were identified and quantified using high-performance liquid chromatography (HPLC). Hydroquinone, 1,2-dihydroxi-benzene, benzoquinone, and pyrogallol were identified as the main Ph degradation intermediates. Pristine RbLaTa2O7 exhibited a phenol conversion value of about 17% using an Xe lamp, while a ≈ 11% conversion was achieved under SSL. A substantial increase in Ph conversion and selectivity was perceived after Fe2+ modification. Fe@RbLTO demonstrated superior photocatalytic performances (43% conversion of phenol under an Xe lamp, and 91% selectivity to aromatic intermediate compounds) at optimized reaction conditions. The stability of the Fe@RbLTO photocatalyst when exposed to an Xe lamp was also assessed. These results suggest that the existence of iron species on the layered perovskite's surface is responsible for the improved redox properties of Fe@RbLTO, resulting in a valuable material for environmental applications.

Optimization of Combined Hydrothermal and Mechanical Refining Pretreatment of Forest Residue Biomass for Maximum Sugar Release during Enzymatic Hydrolysis

This study aimed to investigate the effect of chemical-free two-stage hydrothermal and mechanical refining pretreatment on improving the sugar yields during enzymatic hydrolysis of forest residue biomass (FRB) and optimize the pretreatment conditions. Hot-water pretreatment experiments were performed using a central composite design for three variables: temperature (160–200 °C), time (10–20 min), and solid loading (10–20%). Hydrothermally pretreated biomass was subsequently pretreated using three cycles of disk refining. The combined pretreatment was found to be highly effective in enhancing sugar yields during enzymatic hydrolysis, with almost 99% cellulose conversion for biomass pretreated at 213.64 °C, 15 min, and 15% solid loading. However, the xylose concentrations in the hydrolysate were found to be low under these conditions due to sugar degradation. Thus, less severe optimum pretreatment conditions (194.78 °C, 12.90 min, and 13.42% solid loading) were predicted using a second-order polynomial model. The response surface model optimized the hydrothermal pretreatment of FRB and predicted the glucan, xylan, and overall conversions of 94.57%, 79.78%, and 87.84%, respectively, after the enzymatic hydrolysis. The model-predicted biomass conversion values were validated by the experimental results.

Catalytic co-gasification optimization of biomass and polyethylene wastes in oxygen-rich environments

The catalytic co-gasification of pine wood, palm kernel shell (PKS), and bamboo with varying polyethylene (PE) ratios is investigated to optimize syngas production and identify the effects of different experimental parameters. Oxygen-rich carrier gases are used with an equivalence ratio (ER) of 0.3 at 750 ℃ for gasification. Gasification experiments are devised using the Taguchi method alongside the Box-Behnken Design (BBD), emphasizing four key experimental variables: biomass feedstock, PE ratio, oxygen concentration, and catalyst. In both the Taguchi method and the BBD, the highest cold gas efficiency (CGE) is 65.70%, while the highest carbon conversion (CC) value reaches 86.17%. The parameters yielding these results utilize the P1 catalyst, 29% oxygen concentration, pinewood feedstock, and 50% PE ratio. The key determinant impacting CGE is the polyethylene (PE) ratio within the feed, whereas for CC, it is the catalyst type. The ANOVA-developed prediction model from the BBD currently achieves an R2 of 0.9191 for CGE and 0.9129 for CC. In contrast, the ANN prediction model, employing the Taguchi method, yields an R2 of 0.9708 for CGE and 0.9644 for CC. Furthermore, utilizing an ANN model with the BBD generates an R2 of 0.9734 for CGE and 0.9471 for CC. The developed models can accurately predict CGE and CC. However, the BBD models exhibit superior prediction accuracy compared to the Taguchi model, which is attributed to their larger database for testing. This highlights the effectiveness of both techniques in predicting gasification outcomes, with the neural network model demonstrating superior accuracy in evaluating experimental results.

Two-stage multi-objective distributionally robust operation optimization and benefits equalization of an off-grid type electric-hydrogen-ammonia-methanol coupling system

As the proportion of renewable energy has increased significantly, electric-hydrogen coupling technology has emerged as a pivotal strategy for optimizing the utilization of renewable energy resources. In particular, within the power and chemical sectors, the preparation of ammonia and methanol using electric-hydrogen coupling technology has emerged as the two principal avenues for the utilization of hydrogen energy. However, as a nascent technology, the preparation of ammonia and methanol by electric-hydrogen coupling is confronted with a multitude of challenges, including the considerable uncertainty surrounding the generation of renewable energy, the dearth of economic benefits, and the need to ensure a fair allocation of benefits among the various stakeholders. To enhance the risk resistance of the electric-hydrogen-ammonia-methanol coupling system (EHAMCS), improve the economic benefits, ensure the environmentality and stability of the system, and realize the fair distribution of benefits among the energy participants, this paper constructs a multi-objective distributionally robust optimization (DRO) and multi-dimensional benefits equilibrium model for the EHAMCS and performs a numerical analysis with an off-grid type EHAMCS as an example. The results demonstrate that: 1) The cooperative operation of the EHAMCS offers notable economic advantages. When compared with only pursuing economic benefits, under multi-objective optimization, the economic benefits of the coupling system can be reduced by 1.49 %, but the carbon emission can be reduced by 10.06 %, and the instability is reduced by 0.02, which can create derivative benefits. 2) The two-stage DRO model is an effective means of addressing the impact of system operation uncertainty and the affine strategy enables the rapid adjustment of the day-ahead dispatching plan, thereby balancing the power deviation. 3) The multi-dimensional factor benefit balancing scheme is more conducive to the participation of clean energy and downstream ammonia and methanol energy subsystems in cooperative operation and promotes the consumption of clean energy while improving the energy conversion value of the EHAMCS to increase economic benefits. 4) EHAMCS operators should adjust their operational strategies in time with market and policy signals, and select historical samples reasonably, so as to realize the balance of the DRO model in terms of economy, robustness, and practicality. The effectiveness of the model and the superiority of the EHAMCS are thus verified.

Pengaruh Pemberian Campuran Fermentasi Ampas Tahu dan Dedak Padi Dalam Ransum Terhadap Performa Bebek Hibrida

This study aims to determine the effect of giving a mixture of fermented tofu pulp and rice bran in rations on the performance of hybrid ducks. This research was carried out in Lambanapu Village, Kambera District, East Sumba Regency which took place from November to December 2023, where there was a 2-week adaptation period and 8 weeks of data collection period. This study used an experimental method with a Complete Random Design (RAL) with 4 treatments and 4 replicates, namely P0:BR2 (basal feed), P1: BR2 80% + tofu pulp fermentation 10% + rice bran fermentation 10%, P2: BR2 60% + tofu pulp fermentation 20% + rice bran fermentation 20%, and P3: BR2 40% + tofu pulp fermentation 30% + rice bran fermentation 30%. The results of this study showed that the administration of tofu pulp and fermented rice bran had a real effect (P<0.05) on ration consumption and ration conversion, but had no effect on body weight gain. In conclusion, the application of 40% BR2 and a mixture of fermented tofu pulp 30% and rice bran 30% in the ration can increase ration consumption, but produce a high conversion value and the same body weight gain in Hybrid ducks.

Synthesis Of Ce/Cu/Nb Catalysts, by the One-Step Polymerization Method, Applied in the Selective Oxidation Reaction of Acetonitrile

Objective: The objective of this study is to investigate the catalytic capacity of cerium, copper and niobium oxide catalysts in the oxidation reaction of acetonitrile, in order to test the catalytic behavior, conversion and selectivity of the catalysts; evaluate the different proportions of niobium used (0, 15, 30, 50 and 75% m.m) and compare the catalytic performance of the synthesized materials with other studies present in the literature. Method: The catalysts were synthesized using the one-step polymerization method and were characterized using XRD and H2-TPR techniques. Then, they were applied in the acetonitrile oxidation reaction to be evaluated for conversion and selectivity. Results and Discussion: The results obtained revealed that the catalysts played a significant role in the proposed reaction, obtaining good conversion and selectivity values, including the production of N2 as the majority. Research Implications: Considering that the oxidation of acetonitrile generates polluting gases from nitrogen compounds, the research presents a method that produces an extremely low quantity of these pollutants. This method ensures better product quality, reduces energy consumption due to the lower reaction temperature and uses cheaper and more viable catalysts. Originality/Value: This study contributes to the literature by being based on compounds not yet used together as catalysts and also for the proposed reaction. The relevance of the use of the catalyst is demonstrated through the results obtained, such as high conversions and selectivities to desirable products.

Immobilization of cross-linked enzymes aggregates on hierarchical covalent organic frameworks: Highly stable chemoenzymatic nanoreactor for asymmetric synthesis of optically active halohydrins

Organometallic catalyst is extensively applied for the non-enzymatic regeneration of nicotinamide adenine dinucleotide (phosphate) cofactors, but suffering from the mutual inactivation with the enzymes in one pot. The spatially separated immobilization of organometallic catalyst and enzymes on suitable carriers not only can reduce their mutual inhabitation but also can enhance their reusability. Here in this work, we present a hierarchical porous COFs (HP-TpBpy) that incorporated with [(Cp*RhCl2]2 to generate the metalized COF, Rh-HP-TpBpy. The obtained Rh-HP-TpBpy exhibited superior performance in nicotinamide adenine dinucleotide (NADH) and nicotinamide adenine dinucleotide phosphate (NADPH) regeneration using formate as the hydride donor, significantly outperforming the natural formate dehydrogenases in cofactor preference toward NADP+. Subsequently, the Lactobacillus fermentum short-chain dehydrogenase/reductase 1 (LfSDR1) was then cross-linked into enzyme aggregates (CLEA) and immobilized on hierarchical Rh-HP-TpBpy, achieving the integrated chemoenzymatic catalyst, LfSDR1@Rh-HP-TpBpy, which can catalyze the chemoenzymatic reduction of halogenated aryl ketones and give the corresponding optically active halohydrins with high conversion and enantiomeric excess (ee) value up to 99 %. The LfSDR1@Rh-HP-TpBpy also exhibits largely enhanced stability compared with the free LfSDR1 and the CLEAs-LfSDR1, enabling its excellent reusability.