Heterogeneous Solid Base Catalyst Research Articles

Sustainable Processes Reusing Potassium-Rich Biomass Ash as a Green Catalyst for Biodiesel Production: A Mini-Review

To mitigate the emissions of greenhouse gases (GHGs) from fossil fuels, the use of biodiesel and its sustainable production have been receiving more attention over the past decade, especially for the reuse of waste cooking oils and non-edible oils as starting feedstocks. For the biodiesel production process, the suitability of a green catalyst is a core function in the transesterification reaction. Heterogeneous (solid-state) catalysts are generally superior to homogeneous (liquid-state) catalysts due to several significant advantages such as no saponification products formed, recyclability, and less equipment corrosion. Recent studies also revealed that heterogeneous solid base catalysts were widely used for the production of biodiesel. Furthermore, the use of biomass-based ash derived from herbaceous and agricultural biomass is increasing rapidly because of its environmental sustainability, high biodiesel yield, and low catalyst cost. To highlight alternative catalysts from biomass residues, this mini-review paper thus focused on a summary of various heterogeneous potassium-rich ash materials, which were used as green catalysts for the sustainable production of biodiesel. Due to the abundant quantity and chemical compositions, it was found that ash derived from cocoa pod husk may be the most commonly used solid base catalyst for producing biodiesel in the literature. Finally, future perspectives on biodiesel production by adopting emerging technologies and using high-potassium (K) biomass ash as a green catalyst were also addressed.

Production of Biodiesel from Crude Pittosporum resiniferum Oil Using Heterogeneous Solid Base Catalyst

ABSTRACTPittosporum resiniferum oil was extracted from the seed and the oil together with methanol was use for the production of biodiesel through transesterification process using novel solid base catalyst (K2CO3 supported on MgO). 0.6:5 (K2CO3 loaded on MgO), a 5 h calcination time, 600°C calcination temperatures were the optimum conditions under which the catalyst was prepared. FTIR, SEM, CO2‐TPD, XRD, N2 adsorption‐desorption, Hammett indicators and other techniques were used to characterize the catalyst. The molar ratio of methanol‐to‐oil, the catalyst amount, time of the reaction as well as the temperature of the reaction were examined. The study found that 16:1 methanol‐to‐oil molar ratio, 5% catalyst loading amount, a reaction time of 2.0 h, and a reaction temperature of 60°C were sufficient for a maximum yield of 97.4%. With relative high activity, the catalyst can perhaps be used again possibly for five times. The characteristics of the biodiesel produced were consistent with international standards.

Transesterification of DMC with ethanol over K2CO3/Al2O3: The structure-performance relationship and catalytic mechanism

The transesterification of dimethyl carbonate (DMC) with ethanol to ethyl methyl carbonate (EMC) and diethyl carbonate (DEC) has attracted increasing attention, which could be greatly promoted by heterogeneous solid base catalysts. The K2CO3/Al2O3 solid base catalysts with different active sites such as K2CO3, KAl(OH)2CO3, and KAlO2 were prepared for the transesterification reaction. The active sites of K2CO3 and KAl(OH)2CO3 mainly exist on the surface of KA-200 and KA-300, while K2CO3 and KAlO2 were mainly present on KA-400 and KA-500. The effects of active sites and the phase of support were studied systematically. KAl(OH)2CO3 showed higher activity than K2CO3 and KAlO2. In contrast, K2CO3 and KAlO2 displayed higher stability, with the activity of KA-400 kept stable over 2000 h. The excessive OH group of γ-AlOOH and water in the reaction system have a negative effect on the activity of the K2CO3/Al2O3 catalysts. The catalytic characterizations, transesterification reactions, and DFT calculations suggested that K+ in the KAl(OH)2CO3 species, with higher electron cloud density than that in K2CO3/γ-Al2O3, could efficiently promote the dissociation of ethanol and subsequent replacement of methoxy with ethoxy. The rate-determining step for the transesterification reaction was suggested to be the dissociation of ethanol.

Green synthesis of metal oxides (CaO-K2O) catalyst using golden apple snail shell and cultivated banana peel for production of biofuel from non-edible Jatropha Curcas oil (JCO) via a central composite design (CCD)

The use of biomass as a renewable, sustainable, and eco-friendly energy source is now widely recognized as a potential solution for a variety of environmental problems. To develop biodiesel production, cost-effective feedstocks such as agricultural waste, food waste, and non-edible/waste cooking oil were utilized. A heterogeneous solid base catalyst was synthesized by calcining a mixture of waste golden apple snail shell (Pomacea canaliculata) and cultivated (Musa sapientum) banana peel. In transesterification process, potassium oxide (K2O) derived from banana peel is used as a cocatalyst to improve the catalytic activity of calcium oxide (CaO) catalyst derived from waste shell. The innovative CaO-K2O catalyst was investigated by X-ray diffraction (XRD), X-ray fluorescence (XRF) and the Brunauer-Emmett-Teller (BET) technique. The morphology and elemental composition of calcium (Ca), potassium (K), and oxygen (O) in the catalyst were validated by field emission-scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectroscopy (EDX). The CaO catalyst exhibited a BET surface area of 10.88 m2/g, which was enhanced to 14.62 m2/g upon combination with K2O. The Hammett indicator of CaO catalyst fell between 7.2 < H_< 9.8. However, the CaO-K2O catalyst exhibited a higher value of 15.0 < H_< 18.4, which could be attributed to the phase transition from CaO to CaO-K2O. To investigate the effects of catalyst concentration, ethanol/oil molar ratio, and transesterification time on the yield of fatty acid ethyl ester (FAEE). The optimal conditions for FAEE synthesis were determined using a central composite design (CCD) approach with response surface methodology (RSM). The regression equation obtained for the CCD model has a determination coefficient (R2) of 0.9921, indicating that this model is well-fitted. At 3.69 wt% catalyst concentration, 19.48:1 ethanol/oil molar ratio, and 1.80 h transesterification time, the highest FAEE yield from Jatropha Curcas oil (JCO) of 97.06 % was obtained. The novel catalyst has a strong yield and can be utilized for up to 6 cycles. It was found that the corresponding yield was 90 % when employing the same process parameters, demonstrating the high reusability of this catalyst. The biodiesel produced from non-edible JCO meets the criteria for standard biodiesel (ASTM D-6751 and EN 14214). The CaO-K2O catalyst is inexpensive, easy to make, biodegradable, recyclable, and environmentally friendly because it is derived from a biological residue. Because of these characteristics, it may be an appropriate candidate for the role of “green catalyst” in sustainable energy production.

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.

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.

Carbon‐SO3Na Catalysed Synthesis of Glycerol Carbonate via Transesterification of Glycerol and Dimethyl Carbonate

AbstractGlycerol, a major by‐product from biodiesel industry valorized into glycerol carbonate (GC) employing heterogeneous carbon‐based sulfated sodium (carbon‐SO3Na) catalyst derived from glycerol. Investigations have been conducted to study the influence of reaction parameters such as catalyst dosage, DMC/glycerol molar ratio, reaction temperature and reaction time for the production of GC in high yield with high selectivity from glycerol and dimethyl carbonate (DMC) via transesterification process. Under optimized conditions the maximum GC yield (&gt;99 %) with 100 % selectivity was observed with catalyst dose of 1.5 wt.% (of glycerol), DMC/glycerol molar ratio of 3 : 1, reaction temperature of 80 °C in 3 h of reaction period. Further, the catalyst was easily recovered from reaction mixture and reused without any pre‐treatment. The catalyst maintained its crystalline nature with remarkable performance even after 5 cycles of reaction without any deactivation and leaching. The main advantage of the adopted carbon‐SO3Na catalyzed protocol for the synthesis of GC is environmentally benign due to its high yield and selectivity under mild reaction conditions. Thus, the carbon‐SO3Na catalyst has a wide utility as a potential heterogeneous solid base catalyst for several organic transformations.

Biodiesel Yield and Conversion Percentage from Waste Frying Oil Using Fish Shell at Elmina as a Heterogeneous Catalyst and the Kinetics of the Reaction

In this study, biodiesel was produced from waste frying oil as feedstock with a calcined fish shell under a heterogeneous solid base catalyst. The process of transesterification was done by varying methanol-to-oil molar ratio, catalyst amount, reaction temperature, and reaction time. The heterogeneous catalyst was prepared stepwise as follows: washing and drying the fish shell for 24 hours at 120°C in an oven, then crushing to form powder having been pound for 2-3 minutes in an agate mortar cleaned with nitric acid (6 N). The powdered fish shell was then calcined at 950°C for 4 hours using a muffle furnace. The calcined catalyst was subsequently kept in a desiccator to avoid encountering moisture. The prepared catalyst was then characterized using XRD and FT-IR. The optimum biodiesel yield of 99.58% was obtained under methanol-to-oil ratio of 10 : 1, catalyst amount of 3.0 wt%, reaction temperature of 60°C, and reaction time of 8 hours with mass transfer control of 600 rpm. The optimum rate of constant of 0.164 L/mol·S−1 was determined using the second-order kinetics model. The constant rate of reaction indicated that the forward reaction is crucial for the reaction. The properties of biodiesel produced conformed with those of the international standard using ASTM D6751.

Microwave-assisted synthesis of glycerol carbonate by transesterification of glycerol using Mangifera indica peel calcined ash as catalyst

For the first time, application of Mangifera indica peel calcined ash (MIPCA)-a biomass-derived heterogeneous solid base catalyst is researched for glycerol transesterification with dimethyl carbonate (DMC) to synthesize glycerol carbonate (GC) under microwave irradiation. The appreciable high basicity due to the presence of K2O, CaO and MgO; substantial surface area and mesoporous nature of MIPCA efficiently facilitates the glycerol conversion. Furthermore, the catalyst being biowaste, is hence readily available, economical, biodegradable and environmentally benign. Under the optimum reaction conditions of 3:1 M ratio of DMC: glycerol, 6 wt% catalyst concentration, 80 °C temperature and 50 mins time, microwave irradiation exhibits high conversion (98.1 ± 0.6 %) and improved selectivity (100 %). 1H and 13C NMR were used to characterise the synthesised GC. The catalyst's reusability ensures that it sustains its catalytic activity for up to five consecutive cycles, which is crucial for glycerol to GC transesterification.

Application of converter slag as an effective and low-cost solid base catalyst for the transesterification process

ABSTRACT Calcium oxide is a suitable and valuable catalyst for producing biodiesel. In this research, the feasibility of producing biodiesel from waste frying oil with a new environmentally friendly and low cost heterogeneous solid-base catalyst from waste slag was evaluated. The composition, texture, structure, and chemical characteristics of the converter slag were examined by thermogravimetric analysis (TGA), X-ray fluorescence (XRF), Brunauer–Emmett–Teller (BET), Field Emission Scanning Electron Microscopy (FE-SEM), and X-ray diffraction (XRD). Moreover, the catalyst reusability, reaction conditions, and the effects of catalyst preparation conditions were studied in this experiment. The converter slag was calcined at 1100°C for 8 hours. Gas chromatography (GC) was used to analyse and evaluate the produced biodiesel. The biodiesel characteristics were compared with the ASTM D 6751 standard. It was found that the maximum efficiency of using converter slag for producing biodiesel was 77.8 ± 1.5% under the reaction time 6 hours, catalyst amount 10 wt.%, and reaction conditions of methanol to oil molar ratio 15:1. The converter slag as a catalyst was recovered and reused for three cycles. This study demonstrated how a low-cost catalyst could be used in the production of a value-added product (i.e. biodiesel) from waste oil.

Synthesis of 2-iminothiazolidin-4-ones using guanine functionalized SBA-16 as a solid base catalyst

The first example of a one-pot three-component tandem annulation approach is described for the synthesis of 2-iminothiazolidin-4-ones by the reaction of aromatic/aliphatic amines, aryl isothiocyanates, and ethyl bromoacetate, catalysed by guanine-functionalized SBA-16, [SBA-16@G], as an efficient and recyclable heterogeneous solid base catalyst. The methodology is simple and offers a broad-substrate scope under mild reaction conditions.

Kinetic and optimization study of sustainable biodiesel production from waste cooking oil using novel heterogeneous solid base catalyst

The novel Na-SiO2@TiO2 heterogeneous base catalyst was designed and successfully applied to the trans-esterification reaction of waste cooking oil for sustainable biodiesel production. The designed catalyst was characterized by SEM, XPS, FT-IR and BET before treatment, illustrated its suitability for the catalytic trans-esterification reaction. Moreover, the influence of reaction temperature, time, catalyst concentration and WCO:MeOH molar ratio on the catalytic activity were also investigated, resultant 98% biodiesel yield was achieved. The reusability test demonstrated that the Na-SiO2@TiO2 catalyst has noticeable catalytic potency up to 5 successive runs. Besides, the kinetics study explains that the reaction is kinetically controlled by pseudo 1st order. The Ea was found to be 21.65 kJ/mol. Similarly, the important thermodynamic parameters such as ΔH#, ΔS# and ΔG# were estimated to be 18.52 kJ.mol−1, −219.17 J.mol−1K−1and 92.59 kJ.mol−1respectively.

Waste glass catalyst for biodiesel production from waste chicken fat: Optimization by RSM and ANNs and toxicity assessment

In the current study, a heterogeneous solid base catalyst was manufactured by the reaction of waste glass with NaOH and used to generate biodiesel from chicken fat. The surface technical methods were used to characterize the produced catalyst. The active phase in the catalyst was Na2SiO3. The data showed that the catalyst is efficient to produce biodiesel from chicken fat (90% efficiency up to fourth stages of reuse). The effect of important variables such as reaction time, temperature, catalyst content, and methanol to oil ratio on the biodiesel production efficiency was optimized by RSM-CCD and artificial neural network (ANN). Maximum biodiesel production was calculated as 98.77% and 97.74% using RSM-CCD and ANN, respectively. The quality of the produced biodiesel was checked by ASTM D 6751 and EN 11214 standards. Also, the produced biodiesel was not toxic to plant and microorganisms and it is a biocompatible fuel.

Studies on green synthesis of glycerol carbonate from waste cooking oil derived glycerol over an economically viable NiMgOx heterogeneous solid base catalyst

The present study includes the transesterification reaction of waste glycerol produced in biodiesel industries with dimethyl carbonate (DMC) in presence of magnesium nickel-based mixed oxide, an economically and highly potent cost-effective heterogeneous base catalyst. The catalyst was synthesized in different molar ratios via co-precipitation route. The main objective of this work is value addition of bio glycerol which is major drawbacks in biodiesel industries and economization of biodiesel production process through one of the value added product glycerol carbonate. First-time Ni Mg based mixed oxide catalyst was used in glycerol carbonate synthesis and obtained 82% yield at optimized reaction condition. The physicochemical characteristics of catalysts were analyzed through powder X-ray diffraction (XRD), SEM-EDX, N2-sorption, XPS, FTIR spectroscopy, TGA-DSC. The Gibbs free energy change (ΔG#) and enthalpy of activation (ΔH#) for transesterification reaction of glycerol was found to be 16.547 kJ mol-1 and118.73 kJmol-1 respectively. The positive value of Gibbs free energy change suggested the transesterification of glycerol followed endothermic non spontaneous pathway. Optimization of several reaction parameters like reaction time, temperature, DMC to GLY molar ratio, Catalyst loading percentage were well explained also the green chemistry metrices of the catalyst was studied and found to be very suitable for transesterification reaction of glycerol.

Chitosan as a biodegradable heterogeneous catalyst for Knoevenagel condensation between benzaldehydes and cyanoacetamide

A natural biopolymer chitosan is being employed as heterogeneous solid base catalyst for the Knoevenagel condensation reaction between benzaldehydes and cyanoacetamide under mild reaction conditions. This reaction offers the direct synthesis of condensation product with two functional groups that can readily be functionalized. The biopolymer is used for five cycles with no decrease in activity and hot filtration test proves heterogeneity of the reaction. Some of the salient features of this strategy include biodegradability of catalyst, high catalyst stability, mild reaction conditions and wide substrate scope. The structural integrity is retained even after repeated cycles as evidenced by powder X-ray diffraction (XRD).

Knoevenagel-Doebner condensation promoted by chitosan as a reusable solid base catalyst

The development of green and sustainable processes using naturally occurring biopolymers is becoming one of the suitable remedies to replace the conventional catalytic systems that generate large amount of byproducts with high risk factors. In this context, although Knoevenagel-Doebner condensation reaction has been reported with many organocatalysts including proline, no attempts were made to develop heterogeneous catalysts with environmental concerns. Considering these factors in mind, the title reaction is studied with chitosan as a heterogeneous solid base catalyst for the synthesis of α,β-unsaturated carboxylic acids through the condensation followed by decarboxylation reactions. Chitosan offers many advantages including high stability as evidenced by leaching, reusability tests, wide substrate scope and providing higher yields of the desired products with high purity. Powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR), scanning electron microscope (SEM) and elemental analysis revealed that there are no major changes in the structural integrity and morphology of chitosan before and after catalysis under the optimized reaction conditions.

Kinetika Reaksi Transesterifikasi Minyak Kedelai Menjadi Biodiesel dengan Katalis CaO

The use of biodiesel is expected to reduce dependence on fossil fuels. In this study, the kinetic reaction of transesterification of soybean oil with methanol will be assessed using heterogeneous CaO solid base catalyst with parameters of mole ratio of reactants to the conversion of methyl ester used to determine the reaction velocity equation. The reaction speed equation is used in the design of a fluidized CSTR (Continues Tank Reactor) reactor to obtain the reactor volume and catalyst weight. The purpose of this study was to determine the form of the velocity reaction equation for soybean and methanol transesterification reactions using CaO catalyst and determine the weight of the catalyst needed by using the reaction speed equation. The study was carried out by transesterification of soybean oil and methanol with CaO catalyst with the independent variable mole ratio of reactants while the fixed variable reaction temperature was 60°C, catalyst weight was 3% (% b/v), reaction time was 180 minutes. The results showed that methanol adsorbed on the surface of the catalyst and triglycerides not adsorbed on the surface of the catalyst showed that the mechanism of the catalytic reaction that occurred was the Eley-Rideal mechanism where one of the reactants was adsorbed on the surface of the catalyst. The form of the speed equation for the transesterification reaction of soybean oil and methanol using a CaO catalyst is . The reaction speed equation is used in the design of the reactor, so that the relationship between the weight of the catalyst needed to convert triglycerides to biodiesel and the predicted calculation of the volume of the reactor used can be done.

Palm biodiesel production using by heterogeneous catalyst based corn cobs

In this research, heterogeneous solid base catalysts were derived from corn cobs. the solid base catalyst was obtained which was then used for the production of palm oil biodiesel with a transesterification reaction. The catalyst prepared corn cobs with impregnation of NaOH then calcined temperature 400°C at 2 hours. The optimum conditions for the function of duration reaction time and catalyst amount obtained catalyst amount 3% at 60 minutes, temperature 65°C, ratio methanol to oil 12:1 obtained yield of biodiesel 93.10% while the function of reaction temperature and catalyst amount obtained catalyst amount 2.5%, ratio methanol to oil 12:1, at duration time is 60 minutes and temperature 60°C obtained yields 97.35%. The catalyst was easily separated from the reaction mixture by filtration and able to reuse for 2 times. The biodiesel product is specified with EN14214. Heterogeneous catalysts derived from corn cobs that show high-cost potential and produce easy ones as solid catalysts for the transesterification reaction of biodiesel production.

Preparation and characterization of animal bone powder impregnated fly ash catalyst for transesterification

The present work reconnoitres the feasibility of utilizing class F fly ash and calcined animal bone powder (CABP) as raw material for the synthesis of heterogeneous solid base catalyst with varying ratios (CABP of 10, 20, and 30 mass%), that is subsequently used for transesterification of mustard oil. Physicochemical characterization of CABP revealed crystalline behavior, signifying one of the components as hydroxyapatite (HAP); when calcined at 900 °C transforms to β–tricalcium phosphate having a specific surface area of 100 m2 g−1. The synthesized catalyst showed improved catalytic activity when compared to the parental species and the optimal value to achieve the highest conversion of 90.4% would be at CABP loading of 10 mass%, 5.5:1 methanol to oil molar ratio, and 10 mass% catalyst concentration for 6 h. The prepared biodiesel had a calorific value of 36.2 MJ kg−1 with ash content < 0.01 mass%. The catalyst could be reused five times with no loss in its activity. Results indicated that calcium enriched waste materials when impregnated in fly ash might be a potential source of catalyst in biodiesel production.

Pyridine immobilised on magnetic silica as an efficient solid base catalyst for Knoevenagel condensation of furfural with acetyl acetone

Novel heterogeneous pyridine immobilised magnetic silica (Fe3O4@SiO2-Py) was found to be an efficient, greener and heterogeneous solid base catalyst for the Knoevenagel condensation of furfural with acetylacetone under optimized reaction conditions. The Knoevenagel condensation product 3-(2-furylmethylene)-2,4-pentanedione (FMP), a jet fuel precursor, was produced in high yield of 85% with 94% conversion of furfural at 100 °C within a period of 4 h. Fe3O4@SiO2-Py catalyst showed excellent stability and recyclability without losing its initial activity.