Solid Acid Catalyst Research Articles

Effect of solid acid catalyst coupled decolorization process on the physicochemical properties and bioactive and volatile compounds of sesame oil

SummaryIn this study, the effects of citric acid‐loaded Hβ zeolite (F), activated clay and their modified decolorizers on the nutrients, volatile compounds and harmful substances of sesame oil in the decolorization process were evaluated. The results showed that the decolorization effect of F was second only to that of activated clay, the yield of F‐treated sesame oil sample was not significantly different from that of other decolorizers. The formation of asarinin was detected only in the sesame oil samples treated with F and H (zinc chloride‐activated clay). Compared with the activated clay‐treated sesame oil samples, the retention of tocopherols in the F‐treated sesame oil sample was significantly increased by 23.11%, and the retention of phytosterols was increased by 4.85%. The removal rate of the harmful substances Norharman and Harman in the F‐treated sesame oil sample was 96.79%, which was second only to that of the activated clay. Additionally, the removal rate of the total volatile compounds was the highest at 69.47%. The effects of different decolorizers on the sesame oil samples were closely related to the specific surface area, pore size and surface acidic sites of these decolorizers. This study could provide ideas for the industrial application of leached sesame oil, such as cosmetics and base oils.

Highly efficient hydrolysis of cellulose to sugars using supercritical CO2 as a green acid catalyst and solvent

Rapid depolymerization of cellulose into processable monomers (e.g., sugars) using solid acid catalysts is an important step for cost-effective biofuel and biochemical production, but has not yet been achieved due to the limited contact between solid cellulose and solid catalysts. Herein, the unique roles of supercritical CO2 (i.e., scCO2) as an in-situ acid catalyst and reaction solvent in achieving the ultra-fast full solid catalytic hydrolysis of cellulose are disclosed for the first time. When the ball-milling pretreated cellulose was hydrolyzed using oxidized carbon catalysts at 150 °C and 100–300 bar-CO2, the hydrolysis kinetics remarkably increased by 3× for conversion and 5× for glucose, resulting in ∼90% conversion and ∼85% total sugar selectivity at 20 min. The hydrolysis rate obtained with scCO2 here was higher than conventional ones with toxic and unrecyclable homogeneous catalysts (e.g., HCl) under harsh reaction conditions (i.e., 180–220 °C and pH of 1–2). A comprehensive reaction engineering study (e.g., temperature, CO2 pressure, stirring speed, catalyst acid properties) combined with the estimation of the solution pH by the CO2 phase equilibrium model and the in-situ and ex-situ monitoring of the phase behavior of the H2O/scCO2 solution were conducted to quantify the activity promotion by scCO2 and understand the acid-solvent roles of scCO2 toward the enhanced hydrolysis of cellulose. Specifically, the formation of the Pickering emulsions at the interface between scCO2 and water and their impact on the enhancement of the cellulose-carbon contact were proposed and verified in detail.

Sulfonic acid functionalized SBA−15 catalyst and mercaptopropionic acid promotor for the selective synthesis of p,p′−bisphenol A: Replacement to mineral acid−based process

The significance of selective catalysis in producing plastic monomers is crucial to meet sustainability and economic requirements. It is essential to develop a selective solid acid catalyst to replace irrecoverable corrosive mineral acids and thermolabile sulfonated resins for the production of p,p′−bisphenol A (BPA) isomer, a key intermediate in polycarbonate production. However, limited success has been achieved due to low activity and selectivity towards the desired p,p′−BPA isomer. Herein, a mild and selective route is presented for producing p,p′−BPA using SBA-15 functionalized sulfonic acid catalysts. Sulfonic acid-based catalysts with and without alkyl chain linkers, supported on SBA−15, were synthesized to evaluate the effect of acidity, and textual properties on the catalytic efficiency, and product selectivity. Among all the synthesized catalysts, SBA−15−Pr−SO3H exhibited the highest product selectivity. The addition of mercaptopropionic acid (as a promoter) enhanced the catalytic efficiency and afforded ∼99% acetone conversion, with 97.3% p,p′−BPA selectivity. A detailed mechanism with and without the promoter is proposed. The study also highlights the potential of mesoporous SBA−15−supported sulfonic acid catalysts as a selective and efficient catalyst for synthesizing bisphenol derivatives from the lignocellulose biomass−derived platform molecules, addressing challenges posed by fossil resources.

Lattice Boltzmann Method and Back-Propagation Artificial Neural Network-Based Coke Mapping of Solid Acid Catalyst in Fructose Conversion

Lattice Boltzmann Method and Back-Propagation Artificial Neural Network-Based Coke Mapping of Solid Acid Catalyst in Fructose Conversion

Copper Phthalocyanine Tetrasulfonic Acid, a Recyclable Solid Acid Catalyst for the Synthesis of Aryl Iodides and Azides from Aryl Amines via Diazotization

Copper Phthalocyanine Tetrasulfonic Acid, a Recyclable Solid Acid Catalyst for the Synthesis of Aryl Iodides and Azides from Aryl Amines via Diazotization

Efficient production of biodiesel from palm fatty acid distillate using a novel hydrochar-based solid acid catalyst derived from palm leaf waste

To combat fuel shortages, pollution, and the exhaustion of natural oil resources, an environmentally friendly alternative to fossil fuels, such as biodiesel, is essential for meeting global transportation demands. A novel heterogeneous acid catalyst for production of biodiesel from low-cost, high free fatty acid feedstocks was synthesized in this study by activating and impregnating hydrochar from palm leaf (PL) waste with H3PO4 and H2SO4. Subsequently, the sulfonated catalyst was utilized for the esterification of palm fatty acid distillate (PFAD). FT-IR, XRD, FESEM, EDX, BET, TGA, and surface acidity methods were employed to characterize the acid catalyst. Using the one-variable-at-a-time (OVAT) technique, the optimized reaction conditions for esterification of PFAD using the hydrochar-based catalyst were 4 wt% catalyst loading, 353.15 K reaction temperature, 4 h reaction time, and 18:1 methanol: PFAD molar ratio. At these conditions, a maximum biodiesel yield of 93.56% was achieved. The catalyst exhibited excellent reusability and stability throughout five reaction cycles, maintaining biodiesel yields above 80% after each cycle. Analysis of the fuel properties revealed that the biodiesel derived from PFAD met the physiochemical criteria outlined in ASTM D6751, the American biodiesel standard. The kinetic study revealed that the esterification reaction followed pseudo-first-order kinetics with an activation energy (Ea) of 23.70 kJ/mol. Furthermore, the thermodynamic enthalpy (∆H*) and Gibbs' free energy (∆G*) of esterification were 20.9 and 33.41 kJ/mol, respectively, indicating that the reaction was an endothermic and non-spontaneous process.

Synthesis and characterization of alumina supported molybdosilicic acid (SiMo12/Al2O3): Efficient solid acid catalyst for the synthesis of pyranopyrazole derivatives

A series of highly reusable heterogeneous catalysts (10-40 wt.% SiMo12/Al2O3), consisting of molybdosilicic acid (SiMo12) impregnated on alumina (Al2O3) support was synthesized by the wetness impregnation method. The physicochemical properties of synthesized catalyst were studied using FT-IR, XRD, SEM, EDX, TEM, BET and TG-DTA analysis techniques. The study proves that the synthesized SiMo12 catalyst efficiently incorporated on the surface of Al2O3. The catalytic activity of prepared catalyst was investigated for the synthesis of pyranopyrazole(6-amino-4-phenyl-3-methyl-2,4-dihydropyrano[2,3-c]pyrazole-5carbonitrile) via cyclocondensation reaction of aldehydes, malononitrile, hydrazine hydrate and ethyl-acetoacetate under solvent-free conditions. Among different catalysts, 30% SiMo12 supported on to Al2O3 showed the highest catalytic activity. High yield, shorter reaction time, operational simplicity, solvent-free conditions and reusability of the catalyst are the distinct features of this protocol.

Catalytic hydrothermal conversion of polypropylene

This work reports preliminary-stage studies demonstrating the highly selective conversion of polypropylene to short-chained olefins via hydrothermal catalytic processing. The production of such monomer species from waste polymers is highly desirable and has the potential to play a key role in plastics recycling and in the circular economy more broadly. Addition polymers such as polypropylene are, however, known to be particularly challenging to recycle into propene or other short-chained alkenes. Herein, we have compared and contrasted acid- and base-catalysed hydrothermal processing at a temperature of 360 °C, analysing the products of reaction by gas chromatography – mass spectrometry (GC-MS) and Fourier transform infrared (FTIR) spectroscopy. Employing the basic catalyst K2CO3, results in a 95 % yield of gas-phase products of which 52 % are propene and 9 % butenes on a mole basis. The solid acid catalyst HZSM-5 also selectively yields gaseous products, 21 % of which are propene and 22 % are butenes, the reaction proceeding via β-scission of the starting oligomers. These results represent a potential step-change in the production of monomer units from addition polymers, highlighting the potential value of catalytic hydrothermal processing in the field of polymer recycling.

Synergistic Catalysis of SO42-/TiO2-CNT for the CO2 Desorption Process with Low Energy Consumption.

To address the issue of high energy consumption associated with monoethanolamine (MEA) regeneration in the CO2 capture process, solid acid catalysts have been widely investigated due to their performance in accelerating carbamate decomposition. The recently discovered carbon nanotube (CNT) catalyst presents efficient catalytic activity for bicarbonate decomposition. In this paper, bifunctional catalysts SO42-/TiO2-CNT (STC) were prepared, which could simultaneously catalyze carbamate and bicarbonate decomposition, and outstanding catalytic performance has been exhibited. STC significantly increased the CO2 desorption amount by 82.3% and decreased the relative heat duty by 46% compared to the MEA-CO2 solution without catalysts. The excellent stability of STC was confirmed by 15 cyclic absorption-desorption experiments, showing good practical feasibility for decreasing energy consumption in an industrial CO2 capture process. Furthermore, associated with the results of experimental characterization and theoretical calculations, the synergistic catalysis of STC catalysts via proton and charge transfer was proposed. This work demonstrated the potential of STC catalysts in improving the efficiency of amine regeneration processes and reducing energy consumption, contributing to the design of more effective and economical catalysts for carbon capture.

Modeling and simulation of biodiesel synthesis in fixed bed and packed bed membrane reactors using heterogeneous catalyst: a comparative study

In this study, modeling and simulation of biodiesel synthesis through transesterification of triglyceride (TG) over a heterogeneous catalyst in a packed bed membrane reactor (PBMR) was performed using a solid catalyst and compared with a fixed bed reactor (FBR). The kinetic data for the transesterification reaction of canola oil and methanol in the presence of solid tungstophosphoric acid catalyst was extracted from the published open literature. The effect of reaction temperature, feed flow rate, disproportionation of the reactants, and reactor length on the product performance was investigated. Two-dimensional and heterogeneous modeling was applied to PBMR and the resultant equations were solved by the Matlab software. Moreover, the velocity profile in the membrane reactor was obtained. The results showed the best conditions for this reaction are 180 °C, the molar ratio of methanol to oil equal 15:1, and the input flow rate of 0.5 mL/min. In this condition, a conversion of 99.94% for the TG can be achieved in the PBMR with a length of 86 cm while a length of 2.75 m is required to achieve this conversion of the FBR. Finally, the energy consumption for the production of 8000 ton/y biodiesel in a production plant using the PBMR and the FBR was obtained as is 1313.24 and 1352.44 kW, respectively.

IADOR yields diverse shape-selective solid Lewis acid catalysts

Lewis acid catalysts convert biomass compounds to green chemicals and fuels. Among these catalysts, stannosilicate zeolites display high thermal stability and reusability. However, only a few Sn-zeolites can be prepared using conventional synthesis methods, preventing us from developing shape-selective stannosilicate catalysts. Here, we propose a synthetic approach toward shape-selective Sn-zeolite catalysts, leveraging the Assembly, Disassembly, Organization, Reassembly (ADOR) strategy. By combining isomorphous Sn incorporation (i) into germanosilicate zeolites UOV, IWW, and IWR in the A step with structural modification in the DOR steps, we targeted new Sn-zeolite structures with either parallel or intersecting 12- and 8-ring pores predominantly containing Lewis acid centers with hydrolyzed Sn-O-Si bonds. The shape-selective performance of the designed Sn-zeolite catalysts was experimentally assessed and theoretically rationalized in transformations of citronellal into citronellol by Meerwein-Ponndorf-Verley reduction and into isopulegol isomers via intramolecular cyclization. Therefore, iADOR paves the way toward new zeolite catalysts with engineered Sn active sites for green chemistry.

Facile synthesis of Fe3O4@biochar@SO3H as magnetically separable Bronsted acid nanocatalyst for biodiesel production from different oil feedstocks

A novel magnetically separable Fe3O4@biochar@SO3H catalyst was developed from mesua assamica (King & prain) waste seed shells biochar for cost-effective biodiesel production using novel mesua assamica seed oil, jatropha oil, and soybean oil. The magnetic solid acid catalyst was synthesized via impregnation of biochar with Fe3O4 magnetic nanoparticles followed by sulfonation techniques. Fourier transform infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS) analysis suggested the successful sulfonation and existence of –SO3H groups on catalyst surface. The synthesized magnetic acidic catalyst possesses total acidity of 3.9 mmol g−1 and –SO3H density of 1.8 mmol g−1. The field emission transmission electron microscopy (FETEM) led core-shell structured catalyst particle demonstrated a mean size of 87.4 nm and the surface area of 71.47 m2 g−1. The acidic catalyst easily afforded maximum yield of 96.8% mesua assamica biodiesel, 95.3% jatropha biodiesel, and 95.8% soybean biodiesel under optimized reaction parameters. The kinetic investigation suggested the occurrence of pseudo first order kinetics with activation energy of 32.42 kJ mol−1. The magnetically separable catalyst also displayed promising activity and stability up to 3rd cycle with more than 75% biodiesel yield.

Efficient green synthesis of n-amyl acetate in liquid phase over metal-organic framework catalysts

This investigation describes, for the first time, the efficient and selective liquid-phase green synthesis of n-amyl acetate over UiO-66 and NH2-UiO-66 metal-organic framework catalysts. By employing UiO-66 and NH2-UiO-66 solid acid catalysts, n-amyl acetate can be produced without the corrosive impact and separation problems associated with homogeneous catalysis by mineral acids. Thermal, structural, textural, and morphological properties of the catalysts were evaluated by TG-DTA, XRD, FTIR, Raman spectroscopy, BET-surface area, SEM and HRTEM. Their surface acidities were characterized by the dehydration of isopropanol and the chemical adsorption of suitable probs. The effects of reflux time, acid: alcohol molar ratio, and catalyst load were extensively studied. Under the optimized conditions, UiO-66, and NH2-UiO-66 catalysts, respectively offered 85 and 67 % conversions, and 100 % selectivity into n-amyl acetate. Activity of catalysts was well correlated with the total number of acidic sites, SBET and the kinetic rate constants of the esterification reaction. Analysis of the pre-adsorption studies of the reactants on the catalyst surface demonstrated that the Langmuir-Hinshelwood mechanism was followed in this reaction. The UiO-66 catalyst was regenerated numerous times with nearly the same activity and 100 % selectivity.

One-Step Synthesized Solid Acid Catalyst with High Zr Content for Efficient and Green PET Degradation in Supercritical CO2

One-Step Synthesized Solid Acid Catalyst with High Zr Content for Efficient and Green PET Degradation in Supercritical CO₂

Efficient synthesis of benzoacridines and indenoquinolines catalyzed by acidic magnetic dendrimer

A novel solid acid catalyst with recoverability, named as Fe3O4@SiO2@TAD-G2-SO3H, was successfully synthesized by immobilizing sulfonic acid groups on triazine dendrimer-modified magnetic nanoparticles. This nanomaterial structure and composition were thoroughly characterized using various analytical techniques, including thermogravimetric analysis (TGA), elemental analysis, Fourier transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDX), elemental mapping, acid–base titration, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and vibrating sample magnetometry (VSM). The acid-decorated magnetic dendrimer was served as a highly effective catalyst for the synthesis of tetrahydrobenzo[c]acridin-8(9H)-one and benzo[h]indeno[1,2-b]quinoline-8-one derivatives. The reaction proceeded smoothly under mild conditions through the one-pot condensation of aromatic aldehydes, 1-naphthylamine, and either dimedone or 1,3-indanedione, affording the desired products in high yields ranging from 90 to 96%. The catalyst was easily separated from the reaction mixture by employing a magnetic field, allowing for its recycling up to five times with slight loss in its activity (only 10%). Nearly, quantitative recovery of catalyst (up to 95%) could be obtained from each run. So, this catalyst facilitates the reaction progress and simplifies the purification process. Other remarkable features of this method are operational simplicity, excellent yields, mild condition, and a wide range of substrate applicability.

Catalytic synthesis of aspirin by a single crystal of cadmium phosphomolybdate with (412·612·84)(46)2 topological structure

To green-catalyze the synthesis of aspirin, we designed and synthesized a novel and unreported cadmium phosphomolybdate crystal compound (C2N2H10)4{Cd3[P4Mo6O26(OH)5]2}·6H2O as a catalyst for the synthesis reaction of aspirin using hydrothermal synthesis, and structurally characterized. Single-crystal X-ray diffraction analysis showed that the compound has a 4,8-connected inorganic open topology (412·612·84)(46)2. The optimal process conditions for the reaction of salicylic acid and acetic anhydride were determined by screening the catalyst dosage, temperature, and reaction time. The reaction temperature was set at 80 °C, the catalyst dosage was 0.09 g, and the reaction time was 25 min. The industry's most often utilized catalyst for aspirin manufacturing is concentrated sulfuric acid, which has strong oxidizing and corrosive qualities, resulting in difficult issues such as low synthetic product yield, large equipment needs, and substantial environmental damage. The experimental results of the (C2N2H10)4{Cd3[P4Mo6O26(OH)5]2}·6H2O catalytic synthesis of aspirin reveal that as a solid acid catalyst, its catalytic activity is similar to the commonly used catalyst concentrated H2SO4. Synthetic catalysts, on the other hand, have the advantages of high efficiency, selectivity, conversion rate, ease of recovery, and the ability to be recycled several times without polluting equipment, all of which are consistent with modern ``green'' catalysts. The results of this work suggest that the supramolecular compounds of polymetallic oxonate that we designed and produced hydrothermally can serve as catalysts in drug synthesis reactions to mitigate environmental pollution, hence providing new opportunities for the development of environmentally friendly medications.

Green Catalytic Synthesis of Ethylenediamine from Ethylene Glycol and Monoethanolamine: A Review.

Ethylenediamine (EDA) is a crucial chemical raw material and fine chemical intermediate. Compared with the industrial approach of ammonolysis of 1,2-dichloroethane, the catalytic amination of ethylene glycol (EG) is an economical and environmentally benign route that will be the future trend for EDA synthesis. Herein, we systemically review the recent progress in direct and indirect catalytic conversion of EG to EDA. Furthermore, different types of catalysts are discussed: (i) supported metal and multimetallic catalysts, (ii) solid acid catalysts, and (iii) other active catalysts (e.g., ionic liquids and metal complexes). Finally, we conclude with the frontiers and future prospects of the catalytic synthesis of EDA from EG and monoethanolamine, providing readers a snapshot of this field.

Catalytic and noncatalytic CO2 abs‐desorption studies of MEA‐TETA‐DEEA/MEA‐TETA‐AMP tri‐solvents at specific blended ratios

AbstractTo discover the “coordinative effect” within MEA‐polyamines, the non‐catalytic CO2 absorption‐desorption tests were conducted within tri‐solvents of “MEA‐TETA (triethylenetetramine)‐DEEA (N, N‐diethylethanolamine)/AMP(2‐amino‐2‐methyl‐1‐propanol)” at specific concentrations of .1 ~ .5 + 2 + 2 mol/L for the first time. The energy efficient combinations were detected of MEA‐TETA based tri‐solvents with solid acid catalysts, from catalytic CO2 desorption experiments onto MEA‐TETA‐DEEA/MEA‐TETA‐AMP with several commercial solid acid catalysts: blended γ‐Al2O3/H‐ZSM‐5 = 2:1, H‐mordenite, H‐Beta (Hβ), HND‐580, and HND‐8. Three parameters were adopted to evaluate desorption activity: average desorption rate, heat duty, and desorption factors (DFs). After analyses, the .1 + 2 + 2 mol/L MEA‐TETA‐AMP with catalyst HND‐8 possessed the best CO2 desorption at 95–98°C with biggest DF. The desorption ability of DEEA was better than AMP, but with aid of solid acid catalyst, the AMP can release more CO2 than DEEA due to weak stability of AMP‐CO2− carbamate.

H-Beta Zeolite as Catalyst for the Conversion of Carbohydrates into 5-Hydroxymethylfurfural: The Role of Calcination Temperature

H-Beta zeolite is a solid acid catalyst commonly utilized in the catalytic conversion of biomass resources. In this study, H-Beta zeolite was calcined at different temperatures (350, 550, 750, and 1000 °C) to explore the effects of high temperature-induced dealumination on its physicochemical properties and its catalytic ability to convert glucose into 5-hydroxymethylfurfural (HMF). It was shown that as the calcination temperature increased, the Si-O-Al bond of H-Beta zeolite was broken and its dealumination effect was enhanced. Dealumination led to the collapse of the framework of H-Beta zeolite and a reduction in the number of acid sites, which in turn reduced its catalytic performance and the efficiency of HMF formation from glucose. Furthermore, H-Beta zeolite exhibited an extraordinary catalytic ability for the production of HMF from carbohydrates. Using glucose and cellulose as substrates, superior HMF yields of 91% and 46%, respectively, were achieved under optimal reaction conditions. Further, calcination removes carbon deposits in the recovered H-Beta zeolite, but it affects the cycling stability of the catalyst. Meanwhile, the by-products formed during the synthesis of HMF from glucose catalyzed by H-Beta zeolite catalyst were also clearly detected.

Synthesis of Porous Polymer Based Solid Acid Catalyst Towards Room Temperature Thioacetal/Thioketal Formation

Synthesis of Porous Polymer Based Solid Acid Catalyst Towards Room Temperature Thioacetal/Thioketal Formation