Heterogeneous Base Catalyst Research Articles

Functionalized Biochar from the Amazonian Residual Biomass Murici Seed: An Effective and Low-Cost Basic Heterogeneous Catalyst for Biodiesel Synthesis.

This study presents the synthesis of a basic heterogeneous catalyst based on sodium functionalized biochar. The murici biochar (BCAM) support used in the process was obtained through the pyrolysis of the murici seed (Byrsonimia crassifolia), followed by impregnation of the active phase in amounts that made it possible to obtain concentrations of 6, 9, 12, 15 and 18% of sodium in the final composition of the catalyst. The best-performing 15Na/BCAM catalyst was characterized by Elemental Composition (CHNS), Thermogravimetric Analysis (TG/DTG), X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), and Energy Dispersion X-ray Spectroscopy (EDS). The catalyst 15Na/BCAM was applied under optimal reaction conditions: temperature of 75 °C, reaction time of 1.5 h, catalyst concentration of 5% (w/w) and MeOH:oil molar ratio of 20:1, resulting in a biodiesel with ester content of 97.20% ± 0.31 in the first reaction cycle, and maintenance of catalytic activity for five reaction cycles with ester content above 65%. Furthermore, the study demonstrated an effective catalyst regeneration process, with the synthesized biodiesels maintaining ester content above 75% for another five reaction cycles. Thus, the data indicate a promising alternative to low-cost residual raw materials for the synthesis of basic heterogeneous catalysts.

Bentonite clay as a novel base heterogeneous catalyst in Knoevenagel Condensation of aldehydes with ethyl cyanoacetate in water

Facilely available and cost-efficient bentonite clay was physically purified and chemically modified to investigate the catalytic activity in the heterogeneous catalysis in Knoevenagel condensation of aromatic aldehydes with ethyl cyanoacetate. The classical method of performing this reaction has various environmental issues and limits its industrial applications. This study, to develop modified bentonite clay as a heterogeneous base catalyst for use in Knoevenagel condensation as an alternative to hazardous base catalysts like pyridine, piperidine, etc., Here, the catalytic activities of purified and other incorporated bentonite clays were investigated for the Knoevenagel condensation of aromatic aldehydes with ethyl cyanoacetate. A comparison was made between the catalytic properties of unmodified purified bentonite clay and different metal-incorporated bentonite clays. These catalysts give excellent yields and are inexpensive and easily recyclable for this reaction.

Biodiesel production from transesterified yellow grease by ZSM-5 zeolite-supported BaO catalyst: process optimization by Taguchi’s experimental design approach

Methanolysis of yellow grease (YG) was performed to synthesize its corresponding methyl ester (YGME) using BaO loaded on ZSM-5 (BaO/ZSM-5) as a heterogeneous base catalyst that was prepared via metallic solution hydrolysis method and characterized using N2 adsorption–desorption (BET), surface basicity, XRD, TGA/DTA, SEM, FTIR and Raman techniques.### The Taguchi design approach was utilized to optimize the transesterification process factors, and among the parameters studied, calcination temperature was found to have a significant influence on YGME yield. At 70 ℃ for 3 h, a YGME yield of 95.9 ±0.94\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\pm 0.94$$\\end{document}% was obtained using a methanol/YG molar ratio of 15:1 and 1 g (2 wt.% of YG used) of BaO/ZSM-5 sample calcined at 700 ℃. The BaO/ZSM-5 catalyst was reused six times with only a 15% decrease in activity.

Ru-bentonite catalyzed green Knoevenagel condensation of substituted benzaldehydes with ethyl cyanoacetate

The full-text of the article will be published in the English version of the journal "Catalysis in Industry" No. 1, 2024.To develop Ru-incorporated bentonite clay as a heterogeneous base catalyst for use in Knoevenagel condensation as an alternative to hazardous base catalysts like pyridine, piperidine, etc., we purify the naturally occurring bentonite clay and Ru3+ cation incorporated into its interlayers of bentonite clay to improve its porosity and to increase the surface area of bentonite clay. Purified bentonite and Ru-bentonite were characterized by FTIR, PXRD, HRTEM, SEM & EDS, BET surface area analysis, and TGA. Base activation was done to these clays and a comparative study of these clays as recyclable heterogeneous catalysts for Knoevenagel Condensation was undertaken in water as a solvent for the chemical transformation of 2,4-dichlorobenzaldehyde and 4-hydroxybenzaldehyde with ethyl cyanoacetate into their corresponding α,β-unsaturated acids. The products were characterized by FTIR, 1H NMR, and 13C NMR analyses. The essential key points of this reaction are mild reaction conditions, absence of hazardous chemicals as used in classical Knoevenagel condensation, reusability of the catalyst, and high yield percentage of the products.

An experimental analysis on performance of tobacco seed oil as an alternative fuel for diesel engine

Biodiesel replaced imported oils as an ecologically beneficial alternative which may replace diesel depending on crop and oil costs. Tobacco seed oil is trans-esterified using a heterogeneous base catalyst to produce biodiesel in this study to examine the mechanical properties and emission performance characteristics using single-cylinder Kirloskar engine. Several biofuel/diesel blends were tested, and their effects on performance and efficiency were examined under varying loads at a constant rotational speed of 1500 rpm. The engine's performance and emissions characteristics were measured and compared at a fuel injection pressure of 200 bar. The results of the experimental studies show that the tobacco seed oil and biodiesel blends are more efficient than diesel fuel and their blend ratios that boost brake thermal efficiency by 10.27%, 16.66%, 9.23%, and 11.87% under 25%, 50%, 75%, and 100% of loading, respectively, outperform other biodiesel blends with significant environmentally sustainable emission characteristics.

Metal-Organic Frameworks as Formose Reaction Catalysts with Enhanced Selectivity.

The formose reaction is an autocatalytic series of aldol condensations that allows one to obtain monosaccharides from formaldehyde. The formose reaction suffers from a lack of selectivity, which hinders practical applications at the industrial level. Over the years, many attempts have been made to overcome this selectivity issue, with modest results. Heterogeneous porous catalysts with acid-base properties, such as Metal-Organic Frameworks (MOFs), can offer advantages compared to homogeneous strong bases (e.g., calcium hydroxide) for increasing the selectivity of this important reaction. For the very first time, four different Zeolite Imidazolate Frameworks are presented in this work as catalysts for the formose reaction in liquid phase, and their catalytic performances were compared with those of the typical homogeneous catalyst (i.e., calcium hydroxide). The heterogeneous nature of the catalysis, the possible contribution of leached metal or linkers to the solution, and the stability of the materials were investigated. The porous structure of these solids and their mild basicity make them suitable for obtaining enhanced selectivity at 30% formaldehyde conversion. Most of the MOFs tested showed low structural stability under reaction conditions, thereby indicating the need to search for new MOF families with higher robustness. However, this important result opens the path for future research on porous heterogeneous basic catalysts for the formose reaction.

River snail shell as a highly effective renewable heterogeneous base catalyst for the production of biodiesel

The biodiesel manufacturing process favors heterogeneous catalysts over homogeneous catalysts. The main drawbacks of using homogeneous catalysts are their non-renewable nature, separation, and washing, which can be avoided by using heterogeneous catalysts. This research looks into the shell of a river snail (Viviparidae) that has been improved with modified activated carbon (MAC) as a heterogeneous solid base catalyst for palm oil transesterification. The waste shell was repeatedly washed to remove any organic impurities attached to it and then dried in an oven. It was calcined in an air atmosphere for 2 h at a high temperature of 900 °C. The calcined sample (calcium oxide: CaO) was powdered and mixed with MAC. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and the Brunauer-Emmet-Teller (BET) method were used to characterize the CaO/MAC (mass fraction 3:1) catalyst. In order to optimize the reaction conditions for biodiesel production, operating parameters such as methanol to oil mole ratio, catalyst amount, reaction time, and microwave electrical power were investigated. As a result, the best reaction parameters were discovered to be 12:1 methanol to oil mole ratio, 2.5 wt.% CaO/MAC based on oil weight, 4 min of reaction time, and 600 W microwave electrical power. After being reused five times, the biodiesel yield could still reach 90%, indicating that the novel catalyst had good stability and recyclability. The biodiesel fuel properties obtained in this study were compared to the international biodiesel standards ASTM D6751 and EN14214. River snail shell can be thought of as a nature-based benign and resourceful material for biodiesel production, opening up a new path for fuel sustainability.

Experimental and Simulation Analysis to Predict the Optimum Biodiesel Yield from Two Different Feedstock Using Heterogenous Base Catalyst

Abstract: Biodiesel can be easily used an alternative fuel. Using the Soxhlet apparatus, the oil waas extracted, and centrifuged to separate the oil. The physical characteristics of oil was determined. A number of >3 indicates an acid, while a value < 3 indicates a base. If the FFA content is >0.5, the substance is an acid, and if it’s less than 0.5, a base. Suitable solvent based on its physicochemical characteristics was selected. In this study two types of seeds were used. A mixed heterogeneous base catalyst containing CaO prepared from waste egg shells andcockle shells. The egg shells and cockle shells were dried in microwave oven for 24 hours at 120◦C and placed in Muffle furnace at 900 ◦C and mixed in 1:1 ratio. SEM, EDAX and FTIR were used to characterize the catalyst. The two feedstock used in this study was Solanum Torvum and Murraya Koenigii. Double Step Esterification was preferred. The oil was treatedwith the strong acid H2SO4 . Then oil along with methanol was treated with both acid and basecatalyst separately to give Fatty Acid Methyl Ester. Finally optimum condition was found for maximum yield of FAME, was obtained using RSM.

Nitrogen-Enriched Biguanidine-Functionalized Cobalt Ferrite Nanoparticles as a Heterogeneous Base Catalyst for Knoevenagel Condensation under Solvent-Free Conditions.

Designing efficient, economical heterogeneous catalysts for the Knoevenagel condensation reaction is highly significant owing to the importance of reaction products in industries as well as pharmaceutics. Herein, we have designed and synthesized biguanidine-functionalized basic magnetically retrievable cobalt ferrite nanoparticles (CFNPs) for the synthesis of Knoevenagel condensation products using benzaldehydes and active methylene compounds (malononitrile/ethyl cyanoacetate/cyanoacetamide). Several advanced techniques, such as Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and vibration sample magnetometry (VSM), were utilized to precisely characterize the catalyst. The robust features of the current approach involve outstanding catalytic performance, solvent-free reaction conditions, ease of catalyst retrievability, easy workup procedure, large substrate tolerance, high turnover frequency (TOF) values (up to 486.88 h-1), values of green chemistry metrics such as E-factor (0.15), reaction mass efficiency (RME) value (87.07%), carbon efficiency (93.4%), and atom economy (AE) value (88.10%) close to their ideal values, and recyclability up to eight runs without a considerable reduction in activity, boosting the appeal of this approach from a commercial and ecological point of view.

Optimisation of the reaction conditions for biodiesel from Parkia biglobosa oil via transesterification with heterogeneous clay base catalyst

Transesterification reaction of Parkia biglobosa oil (0.61% w/w free fatty acid and 191.65 (mgKOH/g) saponification value) with methanol to biodiesel using heterogeneous bi-functional Clay-Na2CO3 catalyst was carried out. The bi-functional heterogeneous clay base catalyst was prepared using incipient impregnation method. Following grinding and sieving, the raw clay mineral was soaked in 9 ml Na2CO3 overnight. It was subsequently dried at 120 °C for 12 h and finally calcined at 450 °C for 4 h. The properties of the prepared catalyst was then studied using FTIR, SEM, UV Spectrum, EDS and XRD. The optimum conditions for the transesterification reaction include 12:1 molar ratio of methanol to oil, 2 wt% concentrations of catalyst, reaction temperature of 60 °C and 1.5 h of reaction. The maximum yield obtained under conditions was 94.7%. With the exception of the oxidative stability wahich was higher than the recommended standard by American and European Union, all the other properties of the biodiesel were within the limits of American Standard (ASTM D6751), European Standard (EN 14,241) and Ghana Standard Authority. The catalyst could be cheap with superior activity for which reason it could be a potential candidate for producing biodiesel from new non-edible Parkia biglobosa oil. The application of the biodiesel produced from Parkia biglobosa will help improve the lubrication properties of diesel fuel blend which will subsequently help reduce engine wear in diesel engines since biodiesel is a good lubricant.

Azobenzene-Functionalized UiO-66-NH2: Solid Base Catalysts with Photocontrollable Activity.

Heterogeneous solid base catalysts are highly expected due to their high activity and environmentally friendly nature in a variety of reactions. However, the catalytic activity of traditional solid base catalysts is controlled by external factors (such as temperature and pressure), and regulation of the activity by in situ changing their own properties has never been reported. Herein, we report a smart solid base catalyst by chemically anchoring the photoresponsive azobenzene derivative p-phenylazobenzoyl chloride (PAC) onto the metal-organic framework UiO-66-NH2 (UN) for the first time, which can regulate the catalytic activity through remote control of external light. The prepared catalysts have a regular crystal structure and photoresponsive properties. It is fascinating that the configuration of PAC can be isomerized easily during UV- and visible-light irradiation and resulted in regulation of the catalytic activity. In the Knoevenagel condensation of 1-naphthaldehyde and ethyl cyanoacetate to ethyl 2-cyano-3-(1-naphthalenyl)acrylate, the optimal catalyst shows up to 56.2% of change after trans/cis isomerization, while the change of the yield over UN is negligible. The regulated catalytic behavior can be assigned to the steric hindrance change of the catalysts under external light irradiation. This work may shed light on the design and construction of smart solid base catalysts with tailorable properties for various reactions.

Terminalia arjuna bark – A highly efficient renewable heterogeneous base catalyst for biodiesel production

In agreement with the necessity for green synthesis, the present study elevates the feasibility of exploiting Terminalia arjuna bark calcined ash (TABCA) - a highly functional renewable heterogeneous alkaline catalyst for the cost-effective synthesis of fuel-grade fatty acid methyl esters (FAME) by soybean oil (SO) transesterification under microwave irradiation. The mesoporous nature, significant surface area, and an extreme degree of basicity owing to the presence of CaO, MgO, K2O, SiO2, Na2O, and P2O5 effectively facilitate the SO conversion. Under the optimal conditions of 24:1 M ratio of methanol: SO, 8 wt % catalyst concentration, 80 °C temperature and time period of 60 min, microwave irradiation exhibits highest biodiesel yield (99.2 ± 0.6%) and improved selectivity (100%). Likewise, FAME content in the biodiesel was found to be 99.01% from 1H NMR. The produced SO biodiesel meets the ASTM D6751 and EN 14214 standard requirements, making it compatible in existing engines. In addition, the mesoporous TABCA catalyst showed high stability for five consecutive transesterification reactions which yielded 80 ± 0.8% biodiesel without additional treatments.

Parkia speciosa: A basic heterogeneous catalyst for production of soybean oil-based biodiesel

A green heterogeneous catalyst was fabricated for the biodiesel synthesis via transesterification of soybean oil. The catalyst was generated by simple calcination of the biomass Parkia speciosa (Manipuri beans) at 700 °C. Characterization techniques like TGA, FT-IR, XRD, SEM, BET, TEM, STEM, EDS, XPS, and CO2-TPD were employed to analyse the catalyst. The results showed the existence of significant amount of potassium (K) with some amount of calcium (Ca) in the form of oxides and carbonates which serves as active catalytic sites for accelerating the process of transesterification. The highest biodiesel yield of 96.4 % was achieved at 40 °C, when reaction was performed for 3 h with catalyst loading of 5 wt%, 1:15 M ratio of oil to methanol and 20 wt% of co-solvent. The catalyst has also proved to be truly heterogeneous at low temperature as its efficiency remains intact even after five successive cycles. Thus, the biomass-derived catalyst can be seen as a potentially viable alternative for the conventional homogeneous catalyst.

Karanja seed shell ash: A sustainable green heterogeneous catalyst for biodiesel production

In the present study, the ash from discarded Karanja seed shell (KSS), obtained after burning dried seed shells has been identified as one of the most cost-effective and efficient green heterogeneous catalysts for biodiesel production. Soybean oil methanolsis was used to study the catalytic activity of karanja seed shell ash as solid base heterogeneous catalysts in the biodiesel production. To characterize the catalyst, XRD, WD-XRF, SEM, FT-IR, BET and TGA techniques were utilized. Soybean oil methyl ester was converted under the following experimental conditions, as determined by GC-MS, and FT-IR: a catalyst amount of 2 wt%, a methanol to oil molar ratio of 10:1, a reaction temperature of 65 °C, a reaction time of 60 min. The synthesized heterogeneous catalyst is an efficient alternative that may be utilized as an eco-friendly catalyst because it is benign, reusable, sustainable, and widely available.

Ekstraksi Silika dari Fly Ash Pabrik Kelapa Sawit Menggunakan Variasi Pelarut Karbonat

The selection of a catalyst is imperative in extracting silica. Calcium is a heterogeneous base catalyst that is abundant in carbonate rocks. This study attempts to extract silica using an artificial carbonate solvent with variations of strong acid HCl (1 M, 3 M, 5 M), NaCl salt (1: 2, 1: 4) w/w ratio to distilled water, and H2O (1: 4) w/w ratio to carbonate. Characteristics of fly ash were analyzed using XRF and XRD to determine the elemental composition, crystal structure, and dominant constituent compounds. The solvent concentration and pH effect in extracting silica from fly ash is reviewed by setting the temperature parameter at 60 C, 120 minutes extraction time, and the ratio between fly ash and carbonate solvent 20 % w/v. The filtrate was verified using UV-Vis to determine the concentration of dissolved silica (SiO2) in the carbonate solvent. The examination results showed that the carbonate solvent with 3 M HCl was able to extract silica better than the other five solvents at 68.17 ppm.

Biodiesel Production through the Transesterification of Waste Cooking Oil over Typical Heterogeneous Base or Acid Catalysts

For the production of biodiesel from waste cooking oil with an acid value of 1.86 mg KOH/g, five heterogeneous catalysts—Ba(OH)2, CaO, MgO, ZnO, and AlCl3—were employed. To optimize the reaction parameters of each catalyst, the influence of crucial process variables, such as catalyst loading, methanol-to-oil ratio, and reaction duration, was investigated. In addition, the effect of acetone as a cosolvent toward the progress of biodiesel production and the reusability of the heterogeneous catalysts were also examined, and the data were statistically evaluated with a 95% confidence level. Ba(OH)2 performed exceptionally well, with a 92 wt.% biodiesel yield, followed by CaO with an 84 wt.% yield. However, none of the results for MgO, ZnO, or AlCl3 were adequate. In addition, regardless of the type of catalyst utilized, adding 20 vol.% acetone to the biodiesel manufacturing process led to an increase in output. Furthermore, every heterogeneous catalyst was reusable, but only Ba(OH)2 and CaO produced a significant yield until the third cycle. The other catalysts did not produce yields of any significance.

Biodiesel Production from Chlorella homosphaera by Two-Step Catalytic Conversion Using Waste Radish Leaves as a Source for Heterogeneous Catalyst.

The economic viability of algal biodiesel can be improved by enhancing the microalgal lipid accumulation and using agricultural waste as a cheap and sustainable source of catalysts. In the current study, the effect of various nitrogen concentrations on the growth and lipid of Chlorella homosphaera were investigated. Furthermore, two-step catalytic conversion was applied to convert the oil of C. homosphaera with high free fatty acids (FFA) to biodiesel using waste radish leaves as a source of a heterogeneous base catalyst. The result revealed that the maximum lipid productivity of 25.0mg L-1day-1 and lipid content of 30.83% were obtained under nitrogen-depleted and limited nitrogen conditions, respectively. The FFA was reduced from 18.79 to 0.76%, and the acid value was decreased from 37.4 to 1.52mg KOH g-1 using a 15:1 methanol to oil molar ratio (MTOR), 1.5 wt.% H2SO4, at 60°C for 150min. Under the optimized conditions, i.e., MTOR of 10:1, 3 wt.% of catalyst ratio for 120min at 60°C, the highest oil conversion of 96.61% was obtained. The physicochemical properties of the produced biodiesel were in the range of the standard specification norms for biodiesel. Hence, the proposed two-step catalytic conversion using calcined radish leaves as a heterogeneous catalyst has thus exhibited good potential for biodiesel production using algal oil with high FFA.

Heterogeneous vanadium Schiff base complexes in catalytic oxidation reactions

The chemistry of Schiff base has received remarkable attention in different applications, both organic synthesis and industries. Over the past few years many reports have been on the synthesis, characterization and application of vanadium Schiff base complexes. However, heterogeneous vanadium Schiff base catalysts are active for various oxidation reactions, making catalytic oxidation of hydrocarbons a great interest. This review summarizes the recent development of organic substrate oxidation with heterogeneous vanadium Schiff base catalysts.

Use of a bioresource nanocomposite as a heterogeneous base catalyst for the green synthesis of novel bioactive pyrazoles: antibacterial evaluation using molecular docking

Synthesis and molecular docking of pyrazole derivatives using the heterogeneous basic, CS-DAA/MgO nanocomposite.

Fabrication and characterization of mesoporous yolk-shell nanocomposites as an effective reusable heterogeneous base catalyst for the synthesis of ortho-aminocarbonitrile tetrahydronaphthalenes.

Mesoporous yolk-shell nanocomposites (MYSNs) were loaded with a mobile CaMg core inside the silica shell. CaMg@MYS nanocomposites have been effectively prepared inside the inner cavity of a novel structure that consists of hollow mesoporous silica spheres. Tetraethyl orthosilicate (TEOS) and an amount of cetyltrimethylammonium bromide (CTAB) are coated on the carbon spheres used as a hard template in the multi-step synthetic procedure. In this method, the target products were obtained in high to excellent yields between 87-96% and quick response times between 10-20 minutes under mild conditions. The CaMg@MYS catalyst shows promise as an efficient and reusable catalyst in multicomponent processes. The CaMg@MYS multi-yolk spheres compared to metal oxide nanostructures indicated both high catalytic performance and a significant factor as a novelty. To identify each product, FT-IR, 1H NMR, and melting point techniques were applied. Also, in order to characterize the prepared catalysts, FT-IR, XRD, FE-SEM, EDS, elemental mapping, and HR-TEM techniques were applied.