Catalyst Ratio Research Articles

Research on Catalytic Pyrolysis Process of Coconut Coat of Tropical Agricultural and Forestry Wastes

The effects of reaction temperature, reaction time, heating rate, nitrogen flow rate, and catalyst quality on the oil yield and oxygen content in oil were investigated by using the single-factor principle. Too high and too low reaction temperature, nitrogen flow rate, heating rate, and reaction time improved the yield of bio-oil, but the oxygen content in bio-oil was higher. The reduction in catalytic dose is beneficial to the increase in oil yield but not conducive to the increase in aromatic compound content. The optimal reaction conditions were observed as a reaction temperature of 500 °C, a nitrogen flow rate of 110 mL/min, a heating rate of 20 °C/min, a reaction time of 15 min, a mass ratio of catalyst to coconut coat powder of 1, an oil yield of 4.97%, a water yield of 35.80%, and a solid yield of 30.78%. The gas yield was 28.45%, the oxygen content was 10.3%, and the aromatic compound content was 89.7%. The analysis of the catalytic cracking mechanism shows that most of the oxygen-containing compounds in bio-oil are generated into water and aromatic compounds by a catalytic cracking reaction at high temperature, thus removing oxygen.

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.

Mild one-pot production of glycerol carbonate from CO2 with separation from ionic liquid catalyst

Carbon capture and utilization stands as way forward in the minimization of CO2 emissions. It complements the search for clean and effective energy, as it is challenging to achieve zero to negative CO2 net emissions. The glycerol carbonate product opens a new strategy based on a double-residue approach (glycerol and CO2) to contribute, together with ionic liquids (ILs), drafting a new one-pot concept (intensified three phase reactor) at mild conditions and using homogeneous catalysts. In this work, the catalytic activity of [P666,14][Br] in the cycloaddition of CO2 to glycidol has been demonstrated to be highly effective under mild conditions of 45 °C and 5 bar. In addition, liquid–liquid extraction approach is found to be an efficient separation strategy for carbonate product and IL catalyst. 1-Decanol (DOH) is selected as efficient extracting solvent, due to its almost complete immiscibility with glycerol carbonate, as well as the high distribution ratio of the IL catalyst in DOH rich phase. It implies an easy product separation and, simultaneously, an easy catalyst recovery. A preliminary kinetic validation of the three-phase reactor performance has been properly described, enabling the intensified concept. Finally, combining COSMO/Aspen simulation and life cycle assessment (LCA) methodologies, low energy consumption (avoiding heating) and low GWP scenarios for the CO2 conversion process have been concluded. This work enables a new concept together with concluding the path to developing this CCU technology in the search of zero to negative CO2 emissions to sustainably capture and convert CO2 into value-added products.

Feasibility Study of Rubber Seeds from North Sumatra, Indonesia as Biodiesel Feedstock; Production and Characterization

Abstract There are 5.5 million tons of rubber seeds produced annually on the 3.6 million hectares of rubber plantations that are located in Indonesia. Based on current estimates, 2.4 million tons of biodiesel may be produced if the rubber seeds are utilized as the primary raw material. Rubber seeds are a product of rubber plantations that have not been exploited; to obtain them, there is no need for new land or planting new trees. Rubber seeds are also non-edible, so their use does not conflict with foodstuffs. The purpose of this study was to assess the feasibility of rubber seed as a raw material for biodiesel and to produce and characterise biodiesel from rubber seed. The rubber seeds that have been collected from smallholder plantations in the northern Sumatra region of Indonesia are peeled to separate them from the kernels. Rubber seed kernels are boiled for 4 hours to separate the sap. Kernels that have been boiled are drained and then dried in the sun for 2 days in sunny weather. Kernels that had been dried in the sun were pressed using a screw press, and crude rubber seed oil was obtained. This crude oil is produced into biodiesel through degumming, esterification, and trans-esterification stages. Biodiesel production was carried out with variations in the catalyst ratios of 0.25, 0.5, 0.75, and 1, variations in the ratio of oil/methanol (w/v) of 1:1.25, 1:1.5, 1:1.75 (g/ml), and 1:2, variations in temperature of 50 °C, 60 °C, 70 °C, and 80 °C, and reaction times of 70 minutes, 80 minutes, 90 minutes, and 100 minutes. For each of these variables, the yield of biodiesel produced was calculated. Then the resulting biodiesel is characterised by testing its psychochemical properties against ASTM standards, which include calorific value, oxidation stability, viscosity, density, acid content, cetane number, and flash point. In the experiment on the effect of the amount of catalyst, the largest yield of 85% was obtained when the catalyst ratio (%v/v) was 0.75; in the investigation of the effect of the molar ratio of oil and methanol, the largest yield of 88% was obtained at a ratio of 1.75; the maximum yield of 85% was also obtained at a reaction temperature of 60 °C and 89% at a reaction time of 100 minutes. Almost all of the properties meet ASTM standards, except for the acid value of 0.53 mg KOH/g, which is 0.03 mg KOH/g higher, whereas according to the ASTM D6751-D 664 standard, the maximum acid value is 0.5 mg KOH/g.

Effect of Non-ionic Surfactant on Fe-N-C Catalyst Layers under HT-PEMFC Conditions

The effect of different non-ionic surfactant contents on Fe-N-C gas diffusion electrode (GDE) coating and performance is investigated. GDEs are tested under high temperature polymer electrolyte membrane fuel cell (HT-PEMFC) conditions at 160 °C and concentrated phosphoric acid electrolyteFe-N-C-based GDEs are fabricated through ultrasonic spray coating with Tergitol contents of 0, 1, 20 and 50 wt% in the catalyst layer (CL). Thereby, the PTFE to catalyst ratio is kept constant at 1.0 in the CL. The H2O contact angle decreases with increasing Tergitol™ content in the CL, revealing an increased wettability. H3PO4 contact angles of Tergitol containing GDEs show a same wettability at room temperature as at 160 °C. GDE half-cell setup investigations show, that Tergitol leads to flooding of the electrode by the electrolyte and coverage of the active sites by the surfactant and thus a performance decay.

Effect of Non-ionic Surfactant on Fe-N-C Catalyst Layers under HT-PEMFC Conditions

The effect of different non-ionic surfactant contents on Fe-N-C gas diffusion electrode (GDE) coating and performance is investigated. GDEs are tested under high temperature polymer electrolyte membrane fuel cell (HT-PEMFC) conditions at 160 °C and concentrated phosphoric acid electrolyteFe-N-C-based GDEs are fabricated through ultrasonic spray coating with Tergitol contents of 0, 1, 20 and 50 wt% in the catalyst layer (CL). Thereby, the PTFE to catalyst ratio is kept constant at 1.0 in the CL. The H2O contact angle decreases with increasing Tergitol™ content in the CL, revealing an increased wettability. H3PO4 contact angles of Tergitol containing GDEs show a same wettability at room temperature as at 160 °C. GDE half-cell setup investigations show, that Tergitol leads to flooding of the electrode by the electrolyte and coverage of the active sites by the surfactant and thus a performance decay.

Modeling the aspect ratio of commercial catalysts

AbstractMathematical modeling plays a diverse and crucial role in the chemical industry and academia. This manuscript describes how the physical and mechanical engineering disciplines help the commercialization of catalysts from evaluation to scale‐up and manufacturing. Forming and shaping the catalyst is the first basic step in the catalyst manufacturing industry. Part A shows some of the classic process methods that are employed for this purpose. Catalyst extrudates require proper engineering and process control of their aspect ratio. Catalyst extrudates with a high aspect ratio tend to yield a low reactor fill due to a loose packing. Catalyst extrudates with a low aspect ratio tend to yield high pressure drop. Part B introduces the tensile strength of the catalyst in order to predict the aspect ratio of catalyst extrudates in commercial plants. A force‐balance between the tensile strength of the catalyst and the impact forces due to collision experienced during manufacture leads to the dimensionless group . The group allows to introduce and quantify the severity of equipment and the severity of entire commercial plants.

Preparation of metal-modified carbon-based catalyst and experimental study on catalytic pyrolysis of distillers dried grains with solubles

Distillers dried grains with solubles (DDGS) offer high calorific value, suited for catalytic rapid pyrolysis for energy and chemical applications, yet tar and coke formation during bio-oil upgrading necessitates exploration of cost-effective, durable biocarbon-based catalysts for tar removal. In this study, a carbon-based catalyst was prepared by metal modification of alkaline biochar for catalytic pyrolysis with Distillers dried grains with solubles (DDGS) biomass. Brunauer–Emmet–Teller (BET), X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) were used to characterized the morphology and microstructure of the metal-modified carbon-based catalysts. Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) was used to analysis the pyrolysis-gas of catalytic pyrolysis. Furthermore, the effects of the loading and metal mass ratio of carbon-based monometallic catalysts (Fe and Co) and carbon-based bimetallic catalysts (Fe-Co) on the distribution of the DDGS pyrolysis products were further investigated. The results showed that the 8 wt% of loading rate of bimetallic catalyst significantly reduced the oxygenated compounds but increased the aromatic hydrocarbons. Compared with pyrolysis without catalyst, when the catalyst was 2Fe6Co (mass ratio of Fe/Co 1:3), the hydrocarbons increased from 36.42 % to 44.53 %, the oxygen-containing compounds decreased from 60.36 % to 52.35 %, and the aromatics increased significantly from 0.73 % to 25.37 %. This study provides a new route of increasing the aromatic hydrocarbon content of catalytic pyrolysis to offer theoretical basis for carbon-based catalysts of biomass conversion.

Selective hydrogenolysis of furfuryl alcohol to 1,2-pentanediol over CuMg supported on mesoporous silica: Effect of pore size and shape

Utilizing urea homogeneous precipitation method, Cu and Mg species were successfully supported on SBA-15, KIT-6, and MCM-41 respectively for furfuryl alcohol (FFA) hydrogenolysis to 1,2-pentanediol (1,2-PeD). The catalytic results showed that the yield of 1,2-PeD followed the order of CuMg/SBA-15 > CuMg/KIT-6 > CuMg/MCM-41, especially the maximum of 50.0 % over CuMg/SBA-15 surpassing that of most copper-based catalysts reported. It is found that FFA conversion dramatically increases with the raising of Cu dispersion, attributing to the high exposure of active sites. Meanwhile, the selectivity of 1,2-PeD is strongly depended on the Cu0/Cu+ ratio of catalyst and CuMg/SBA-15 with the highest value of 57.6 % is derived from the largest Cu0/Cu+ ratio. In a word, CuMg/SBA-15 shows the excellent activity along with stability owing to the synergy between large Cu0/Cu+ ratio and good Cu dispersion, providing by two-dimensional hexagonal straight channel arrangement with generous pore diameter. Innovatively, it is put forward that dual adsorption sites of both MgO and Cu species in the CuMg/SBA-15 catalyst promote the FFA ring-opening to yield 1,2-PeD based on the comparison of Cu dispersion, metal-support (M−S) interaction and the adsorption capacity for furan rings with Cu/SBA-15. This study provides a novel approach for catalyst design for this reaction, focusing on optimizing the catalytic performance by fine-tuning structure of the support.

Toward Fully Controllable Monomers Sequence: Binary Organocatalyzed Polymerization from Epoxide/Aziridine/Cyclic Anhydride Monomer Mixture.

The sequence of monomers within a polymer chain plays a pivotal role in determining the physicochemical properties of the polymer. In the copolymerization of two or more monomers, the arrangement of monomers within the resulting polymer is primarily dictated by the intrinsic reactivity of the monomers. Precisely controlling the monomer sequence in copolymerization, particularly through the manipulation of catalysts, is a subject of intense interest and poses significant challenges. In this study, we report the catalyst-controlled copolymerization of epoxides, N-tosyl aziridine (TAz), and cyclic anhydrides. To achieve this, a binary catalyst system comprising a Lewis acid, triethylborane, and Brønsted base, t-BuP1, was utilized. This system was utilized to regulate the selectivity between two catalytic reactions: ring-opening alternating copolymerization (ROAC) of epoxides/cyclic anhydrides and ROAC of TAz/cyclic anhydrides. Changing the catalyst ratio made it possible to continuously modulate the resulting poly(ester-amide ester) from ABA-type real block copolymers to gradient, random-like, reversed gradient, and reversed BAB-type block-like copolymers. A range of epoxides and anhydrides was investigated, demonstrating the versatility of this polymerization system. Additionally, density functional theory calculations were conducted to enhance our mechanistic understanding of the process. This synthetic method not only provides a versatile means for producing copolymers with comparable chemical compositions but also facilitates the exploration of the intricate relationship between monomer sequences and the resultant polymer properties, offering valuable insights for advancements in polymer science.

TG-FTIR-Py-GCMS analysis and catalytic pyrolysis mechanism of textile waste by red mud catalyst for liquid fuel production

The substantial generation of textile waste (TW) and red mud (RM) has resulted in significant resource wastage and environmental challenges. Co-utilization technology of solid waste is an effective approach to improve waste utilization efficiency. In this study, RM catalytic pyrolysis experiments of TW were conducted using TG-FTIR and Py-GC–MS for liquid fuel production, and TW and RM were recycled simultaneously. At the optimal experimental conditions (temperature of 600 °C and feed catalyst ratio of 2:1), the tar yield and higher heating value (HHV) of TW pyrolysis catalyzed by RM were 73.43 wt% and 32.34 kJ/g, respectively. Additionally, experiments on the pyrolysis of various TW types revealed that LDPE and PP are suitable for tar production, while cotton, nylon, and PET are more suitable as feedstock for syngas production. The RM catalytic pyrolysis mechanism of textile waste is that Fe2O3 in RM exhibits significant catalytic activity in enhancing tar and syngas yields. However, during the catalytic process, Fe2O3 undergoes reduction to Fe3O4, resulting in diminished catalytic performance of the RM. After five cycles of use, the RM essentially lost its catalytic activity due to the accumulation of char and tar. All experimental findings of this study could offer an effective guideline for TW recycle and promoting RM utilization toward the waste-to-energy circular economy.

Investigation of different ratio of CuCe catalysts applied in photothermal reverse water gas shift reaction

The photothermal catalytic reverse water gas shift reaction (RWGS) can convert CO2 into other high-value-added chemical resources under mild conditions. However, the design and development of high-performance catalysts is a major challenge. In this work, different proportions of CuCe bimetallic catalysts were synthesized using the sol-gel method and applied to RWGS. Under the visible light heat catalytic condition at 450 ℃, the CO yield can be increased by about 20 % compared to thermal catalysis, which is better than most metal-based catalysts reported in the literature. Moreover, the catalyst exhibited good stability and reusability, with the primary factor affecting the stability of the CuCe catalyst being the growth of Cu nanoparticles. The characterization shows that at Cu/Ce=1, the separation efficiency of electron-hole separation is the highest, and the hot electrons generated by the LSPR effect of Cu can be effectively separated and transferred, producing more oxygen vacancies and suitable alkaline sites, so it has the best photothermal catalytic performance. Furthermore, the catalyst is dominated by the formate pathway under light conditions, and this work provides a new RWGS strategy.

Kinetics, thermodynamics, and optimization analyses of lipid extraction from discarded beef tallow for bioenergy production

ABSTRACT The wide expansion of the meat industry generated tremendous amounts of animal-based waste. Discarded beef tallow (DBT) is one of those prevalent lipid-rich wastes disposed of by slaughterhouses, meat processing units, and tanneries. The current study utilized the advanced technology of supercritical CO2 (SC-CO2) to extract lipid content from DBT for biodiesel production through transesterification. The effects of SC-CO2 parameters on the extraction rate were investigated over ranges of (32–80°C) for temperature, (10–50 MPa) for pressure, and (15–150 min) for treatment time. Using response surface methodology (RSM), both processes of SC-CO2 and transesterification were optimized. The highest extraction rate was 86.10%, obtained at the experimental conditions of 60°C for temperature, 30 MPa for pressure, and 120 min for treatment time. For the transesterification, the maximum yield of biodiesel was 95.15%, obtained at the reaction conditions of 1:7.5, 1.16 wt%, 58°C, and 72 min for lipid to methanol molar ratio, catalyst ratio, temperature, and time, respectively. The outcomes of the kinetic and thermodynamic analyses showed that the SC-CO2 extraction was an endothermal, unspontaneous, and temperature-dependent process. The characteristics of the synthesized biodiesel largely comply with the ASTM D6751 and EN 14,214 standards. The findings of the current study confirm the viability of SC-CO2 to extract lipids from DBT as a low-cost feedstock for biodiesel production.

Synergistic Photoredox/Palladium Catalyzed Enantioconvergent Carboxylation of Racemic Heterobiaryl (Pseudo)Halides with CO2.

Herein, we report a synergistic photoredox/palladium catalytic system for the efficient enantioconvergent synthesis of axially chiral esters from racemic heterobiaryl (pseudo)halides (bromides/triflates) with CO2 and alkyl bromides under mild conditions. A wide range of axially chiral esters were obtained in good to high yields with excellent enantioselectivities. Detailed mechanistic studies unveiled that the ratio of photocatalyst and palladium catalyst exhibited significant impact on the chemo- and enantioselectivities of the reaction. Kinetic studies and control experiments supported the proposed mechanism involving cascade asymmetric carboxylation followed by SN2 substitution. The achievement of high enantioselectivity relies not only on the choice of synergistic metallaphotoredox catalysts but also on the utilization of alkyl bromides, which trap the generated chiral carboxylic anions in situ, thus preventing their immediate racemization.

Surface- modified preparation of CuFe2O4/sodium alginate hydrogel catalysts for the long-lasting degradation of tetracycline

Copper ferrate spinel (CuFe2O4) catalysts are widely used in advanced oxidation processes for environmental wastewater treatment due to their advantages of low price, mild reaction conditions and ease of operation. Therefore, it is crucial to investigate the factors influence the surface properties of catalysts on their catalytic activity. In this research, the effects of process parameters on the surface properties of CuFe2O4 were investigated, and the relationship between the surface properties of CuFe2O4 and its catalytic activity was clarified. The optimised CuFe2O4 exhibited 92.4 % degradation of tetracycline (TC) and 55 % mineralisation of total organic carbon (TOC) within 30 min, the pseudo-first-order reaction rate was 0.0315 min−1, which was 2.2 times higher than that of the unoptimised CuFe2O4. The mechanism of action for enhancing catalyst performance and the degradation mechanism of tetracycline were clarified through a combination of characterization analysis. To further solve the problems of secondary pollution caused by ion leaching and the difficulty of practical application of powder catalysts, novel hydrogel microspheres composed of sodium alginate and CuFe2O4 were prepared by using the property of metal ions and sodium alginate to form a solid gel (SA/Ort-6). SA/Ort-6 was characterized by low ion leaching, excellent performance and excellent stability. The mass ratio of catalyst to treated water could be up to 1:22,000, and the mass ratio of catalyst to treated water can reach up to 1:22000, the removal rate of TOC was stable above 35 %. This study provides valuable insights into the relationship between surface properties and catalytic performance of CuFe2O4, offers a new approach to effectively solve leaching of metal ions, and opens up a new avenue for practical application of powder catalysts.

Strongly tribocatalytic dye degradation of high-entropy powder through harvesting friction

The omnipresent friction can be harvested to generate electricity, thereby facilitating redox reactions to degrade dye wastewater, which can be named as tribocatalysis. Here, it’s experimentally found that the high-entropy CoCrFeMnNi powder synthesized via the Vacuum Induction Gas Atomization (VIGA) technique, can behave the obvious tribocatalytic Rhodamine B (RhB) dye degradation performance. In the tribocatalysis dye degradation process, friction occurs at the interface between the catalyst’s surface and the stirring Teflon rod. The tribocatalytic RhB dye degradation ratios of the high-entropy CoCrFeMnNi powder catalysts at stirring speeds of 200 rpm, 400 rpm, 800 rpm, 1000 rpm, and 1200 rpm are 14.7 %, 70.3 %, 93.2 %, 99.4 %, and 99.8 %, respectively. It’s also found that the RhB dye degradation ratio can be slightly enhanced under an external DC magnetic field provided by a commercial NdFeB magnet, which may be attributed to the magnetically-induced enhancement of separation efficiency of these positive and negative carriers. After being recycled for 3 times, the CoCrFeMnNi powder can still degrade 90.8 % RhB dye. The CoCrFeMnNi powder with the excellent tribocatalytic activity is potential for application in dye wastewater treatment through utilizing the friction energy in the environment.

Scaling a bifunctional catalytic Fixed-Bed reactor for acetone-to-mesitylene Jet-Fuel additive production

De-fossilization of the aviation sector will require the use of renewable synthetic jet fuels and additives that comply with strict regulations. One such additive, mesitylene, can be produced using a novel sustainable process based on the fermentation of biomass waste to acetone, followed by the self-condensation of acetone to mesitylene. This study addresses the viability of gas-phase self-condensation of acetone, catalyzed by TiO2 and Al-MCM-41 acid catalysts, at a technological readiness level of TRL-4.The reactor used was a bench-scale fixed-bed reactor (28 mm diameter and 500 mm height) loaded with commercial-sized catalyst pellets (1/8″ diameter). It was equipped with a jacket for heat transfer using flowing thermal oil. The performance of commercial-scale reactors was approximated under conditions of 275 °C, 280 kPa, and a space velocity of 50–500 mol/kg·h.The catalyst pellets exhibited significant mass transfer resistances, which limited the reaction rate. This, in turn, reduced the deactivation rate caused by the adsorption of high-molecular-weight condensation products on the strongest acid sites. Additionally, the product distribution differed between pellet and powder forms of the catalysts, with higher yields of isophorone and mesitylene being observed on TiO2 and Al-MCM-41 pellets, respectively. A reaction and mass transfer model was proposed and fitted to the bench-scale data.The study also considered the combination of both catalyst pellets in the same reactor for the bench-scale unit. It was demonstrated that mesitylene yield could be improved, with the best configuration being two separate beds placed consecutively in the reactor with a catalyst ratio of 1:2 (TiO2:MCM-41).

(Invited) Degradation and Poisoning of Proton-Exchange Membrane Water Electrolyzer Anode Catalysts

Hydrogen production through water electrolysis is a crucial technology to enable the transition to a carbon neutral, hydrogen-based economy. One of the primary types of electrolyzers is the low-temperature proton-exchange membrane water electrolyzer (PEMWE). As with the analogous proton-exchange membrane fuel cells, platinum group metal electrocatalysts are utilized due to their activity and stability in acidic environment. Electrocatalysis R&D efforts for PEMWEs primarily focus on the oxygen evolution reaction (OER) since it is several orders of magnitude kinetically slower than the hydrogen evolution reaction (HER).1 Iridium-based metal oxides (IrOx) are regarded as the best PEM electrolyzer electrocatalysts as they balance activity and stability.2 However, improvements are needed in both areas to enable minimization of Ir loading to meet system cost targets while also meeting challenging performance and lifetime targets.3 An understanding of the factors affecting both the activity and stability of Ir-based OER catalysts is needed to develop strategies to enable both high OER activity and long-term stability of the PEMWE anode catalyst.This presentation will describe our studies of the effects of perfluorosulfonic acid (PFSA) binder on the OER kinetics and the factors influencing the stability of two commercial Ir-based OER catalysts, one comprised of IrOx only and the other also containing TiOx. Measurements of OER kinetics as a function of ionomer to catalyst ratio utilizing rotating disc electrode and cavity microelectrode methods in an acidic aqueous electrochemical environment will be described. Dissolution and loss of Ir under the operating conditions of the PEMWE anode is considered to be one of the main PEMWE anode degradation mechanisms.4 To understand the factors affecting this phenomenon, the potential and time-dependence of Ir (and Ti) were determined using an electrochemical flow cell system connected to an inductively-coupled plasma-mass spectrometer (ICP-MS) capable of detecting trace concentrations (<ppb) of dissolved elements in solution. The electrochemical data combined with the ICP-MS data have been used to evaluate the influence of various factors such as potential, potentiodynamic profile parameters (e.g., scan rate, upper and lower potential limits) on the dissolution processes in acidic aqueous electrolyte at room temperature.AcknowledgementsThis research is supported by the U.S. Department of Energy, Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cell Technologies Office under the auspices of the H2NEW Consortium. Argonne National Laboratory is managed for the U.S Department of Energy by the University of Chicago Argonne, LLC, also under contract DE-AC-02-06CH11357.References A. Raveendran, M. Chandran, and R. Dhanusuraman, RSC Adv., 13 (2023) 3843.J. Ouimet, J.R. Glenn, D.D. Porcellinis, A.R. Motz, M. Carmo, K.E. Ayers, ACS Catalysis, 12 (2022) 6159."Technical Targets for Proton Exchange Membrane Electrolysis", U.S. Department of Energy, Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cell Technologies Office, March, 2023.Zeng, R. Ouimet, L. Bonville, A. Niedzwiecki, C. Capuano, K. Ayers, A.P. Soleymani, J. Jankovic, H. Yu, R. Maric, et al., J. Electrochem. Soc., 169(5) (2022) 054536.

Unconventional Ligand‐to‐Catalyst Ratio for the Distal C−C Bond Formation via C−H Activation and Chain‐Walking

AbstractA mechanism‐navigated enantioselective alkylation of an indole C2 C−H bond with an internal alkene was developed. Under the unconventional ligand‐to‐metal catalyst ratio, a moderate enantiomeric ratio (er), ranging from 70:30 to 88:12, was achieved with our original ligand. We propose that chain‐walking and bond formation are mechanistically independent and suggest that hydridoiridium generated from the C−H source does not play a role in the chain‐walking process.

Effect of CaO/Fe2O3 Ratio and Oil/Methanol Molar Ratio on Biodiesel Production from Waste Cooking Oil

Biodiesel is a renewable liquid fuel that can be produced through the transesterification reaction of biomass. The objective of this research was to examine the effect of comparative composition of CaO and Fe2O3 on CaO/Fe2O3 catalysts from eggshells and Fe2O3 in the production of biodiesel from waste cooking oil. In addition, it was also studied the effect of the ratio of oil and methanol on the yield and characteristics of the biodiesel produced. Catalysts were prepared through impregnation. The esterification-transesterification process was carried out with the conditions WCO:methanol molar ratio of 1:3, 1:6, 1:9, 1:12 and 1:15, catalyst (3%wt oil), heated at 65°C for 3 hours with a stirring scale of 1200 rpm. The results showed biodiesel production using CaO: Fe2O3 catalyst with the ratio of CaO: Fe2O3 70:30 and WCO:methanol molar ratio of 1:9 obtained higher yield (84.5%) compared to others. The best biodiesel yield produced is the CaO:Fe2O3 catalyst ratio of 70:30 and the WCO:methanol molar ratio of 1:9 with a biodiesel yield of 84.50% with a methyl ester content of 99.63% and a FAME yield of 84.14%. The biodiesel produced has met the requirements of the Indonesian National Standard (SNI) in terms of density and viscosity.