Acetalization Of Glycerol Research Articles

Influence of sulphonation on Al-MCM-41 catalyst for effective bio-glycerol conversion to Solketal

Al-MCM-41 and sulphate modified Al-MCM-41 catalysts with variable sulphate loadings (0.25-1SAM) were synthesized through sol-gel and impregnation techniques respectively for the transformation of glycerol into solketal, a fuel additive via acetalization reaction. The mesoporous structure, surface morphologies, composition and porosity of the prepared catalysts were subjected to characterization by Low angle XRD, SEM-EDAX, TEM, FT-IR, XPS and BET-surface area studies. The strength and quantification of acid sites were obtained from TPD of NH3. Pyridine-adsorbed FTIR and 27Al MAS NMR data distinguished Lewis and Brønsted acid sites present on the catalysts. Among the synthesized catalysts, 1 N sulphated Al-MCM-41 was a better catalyst that promotes a higher solketal formation rate of 23.5 mmol h−1g cat−1 by the acetalization of glycerol. This is much higher in comparison to 4 times lesser activity of 6.1 mmol h−1gcat−1 exhibited by the parent Al-MCM-41. This catalyst further showed consistent activity and reusability up to 5 cycles. Large surface area, total acidity, strong Lewis acid sites, compatible surface characteristics of 1 N sulphated Al-MCM-41 endorse the higher acetalization activity of the catalyst. As a result, these parameters have been regarded as crucial considerations in designing a better catalyst in the effective conversion of glycerol to solketal.

Heteropolyacid supported on ionic liquid decorated hierarchical faujasite zeolite as an efficient catalyst for glycerol acetalization to solketal

To handle huge amount of glycerol produced in biodiesel industry, glycerol is transformed to value-added products. In this regard, glycerol acetalization to solketal is industrially attractive. As in this process various by-products can be formed, designing highly selective catalysts is of great importance. In this line, we wish to report a novel catalyst that benefits from strong acidity, high specific surface area and thermal stability, which can selectively form solketal in glycerol acetalization. To prepare the catalyst, hierarchical zeolite was prepared via a novel method, in which partially dealuminated NaY was treated with PluronicF-127 and then reacted with NH4NO3 to furnish the H-form zeolite. Hierarchical faujasite was then achieved through calcination and template removal. Subsequently, it was functionalized with ionic liquid and used for the immobilization of heteropolyacid. The results indicated the importance of the mesoprosity of zeolite and the presense of ionic liquid functionality for achiveing high solketal yield. Moreover, among three investigated heteropolyacids, phosphomolybdic acid exhibited the highest catalytic activity. In fact, using 10 wt% catalyst at 55 °C and glycerol to acetone molar ratio of 1:20, solketal with yield of 98% was furnished under solvent-less condition. Besides, the catalyst was recyclable with low leaching of heteropolyacid.

Producing polyglycerol polyester polyol for thermoplastic polyurethane application: A novel valorization of glycerol, a by-product of biodiesel production

The production of biodiesel generates glycerol as a by-product that needs valorization. Glycerol, when converted to polyglycerol, is a potential polyol for bio-based thermoplastic polyurethane (TPU) production. In this study, a novel polyglycerol polyester polyol (PPP) was developed from refined glycerol and coconut oil-based polyester polyol. Glycerol was first converted to glycerol acetate and then polymerized with coconut oil-based polyester polyol (CPP) as secondary polyol and phthalic anhydride. The resulting PPP polymerized at 220 °C and OH:COOH molar ratio of 2.5 exhibited an OH number of <100 mg KOH·g sample−1, an acid number of <10 mg KOH·g sample−1, and a molecular weight (MW) of 3697 g mol−1 meeting the polyol requirement properties for TPU (Handlin et al., 2001; Parcheta et al., 2020) [1-2]. Fourier-transform infrared (FTIR) spectroscopic characterization determined that higher reaction temperatures increase the polymerization rate and decrease the OH and acid numbers. Further, higher OH:COOH molar ratios decrease the polymerization rate and acid number, and increase the OH number. Gel permeation chromatography determined the molecular weight of PPP and suggested two distinct molecular structures which differ only in the number of moles of CPP in the structure. A differential scanning calorimetric (DSC) experiment on a sample of PPP-based polyurethane revealed that it was able to melt and remelt after 3 heating cycles which demonstrates its thermoplastic ability. The novel PPP derived from the glycerol by-product of biodiesel industries can potentially replace petroleum-derived polyols for TPU production.

Preparation of a poly(2-acrylamido-2-methyl-1-propanesulfonic acid)-grafted polyurethane sponge using atmospheric pressure plasma-induced graft polymerization and its catalytic properties for the acetalization of glycerol to solketal

Poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (poly(AMPS)) bearing a sulfo group was grafted onto a polyurethane sponge by an argon atmospheric-pressure plasma treatment and subsequent graft polymerization. Thus, a novel poly(AMPS)-grafted polyurethane sponge was developed as a heterogeneous acid catalyst for organic synthesis. The average grafting amount was 0.0277 kg-polymer/kg-substrate. The surface properties of the polyurethane sponge changed considerably, from hydrophobic to hydrophilic. The poly(AMPS)-grafted sponge successfully catalyzed the acetalization of glycerol with acetone to produce the desired solketal. The reaction rate was analyzed using a pseudo-first-order kinetic model, and the apparent reaction rate constant, k, and apparent activation energy were determined. The k value for the poly(AMPS)-grafted sponge was one order of magnitude larger than that for the EDGA-co-AMPS gel (EDGA: ethoxy diethyleneglycol acrylate). The poly(AMPS)-grafted sponge with interconnected submillimeter-sized macropores and high porosity (98%) exhibits excellent diffusional permeability. In addition, the structural features of the sponge provide advantages such as a negligible pressure drop and easy handling during the reaction process. This study provides a strategy for the use of polymers grafted onto sponges as catalysts.

Synthesis of oxygenated additive fuels from bio-renewable glycerol using sulfated Zr-Al based heterogeneous acid catalyst

The exponential growth of biodiesel production generates an enormous amount of glycerol as a by-product that requires effective strategies to convert it into valuable chemicals to enhance the sustainability of the biodiesel market. Solketal is an interesting compound among various value-added chemicals obtained from waste glycerol produced during biodiesel production. In the present work, highly efficient and economically viable heterogeneous solid acid SO4-2/ZrO2-Al2O3 catalyst was designed via wetness impregnation process. The synthesized catalyst was found to be highly active for acetalization of glycerol with acetone under optimized conditions viz. 1:10 M ratio of glycerol and acetone, 3 wt.% of catalyst loading at 70 °C for 180 min reaction time. The synthesized catalyst is highly selective (98.9%) for solketal synthesis, with 98.1 % yield and 99.2 % glycerol conversion. Green metrics studies were performed to determine the environment-friendly nature of the catalyst and acetalization process. The carbon balance studies were also calculated to show that glycerol is found only in one phase during the overall process of solketal synthesis. The high thermal stability and catalytic activity were retained up to 5th reaction cycle making the catalyst more efficient for its wide application in an industrial level.

Process intensification of microwave-assisted acetylation reaction of glycerol to synthesize fuel additives using porcine pancreas lipase catalyst

To reduce the level of greenhouse emissions, new technical advancements in the fields of biofuels, wind, and solar energy are being made. The most widely used biofuel is biodiesel. Glycerol production has grown as a result of increased biodiesel production. Glycerol may be processed to create valuable chemicals. In this research, a glycerol acetylation reaction with acetic acid was carried out to synthesize glycerol acetate using an enzyme lipase catalyst extracted from porcine pancreas (PPL). Experiments were carried out to analyze the effect of various solvents (toluene, n-butyl alcohol, tert-butyl alcohol, dichloromethane, isopropyl alcohol), power level (900 and 1200 W), and temperature (20–50 °C) on glycerol conversion. Ninety-six percent of glycerol conversion was achieved for a duration of 2 h with the use of 10 mL of toluene as solvent. The kinetics of the acetylation reaction catalyzed by PPL in a microwave reactor was also studied using an elementary kinetic law. Applying process intensification using a microwave reactor was found to be advantageous. The microwave effect in accelerating the rate of acetylation reaction at reduced temperature compared to the conventional method was observed in this study. The activation energy (E) for the acetylation reaction was found to be 18 kJ/mol.

Glycerol Acetalization in Cyclopentyl Methyl Ether with Mild Acid Catalysts

AbstractReaction of glycerol with aldehydes and ketones is a strategy widely studied in literature to valorize this bioproduct. A Brønsted or Lewis acid is normally used to activate the carbonyl function and various strategies adopted to drive the equilibrium to the products. In this study ammonium salts as catalysts, and removal of water by azeotropic distillation of cyclopentyl methyl ether, permit the conversion of glycerol into acetals obtained as mixture of dioxanes and dioxolanes determined by 1H‐NMR. Under the optimized conditions, the products could be obtained in excellent yield without using excess of reactants and the solvent was recycled efficiently.

Acetalization of glycerol with acetone over UAV-59 catalyst: Mild reaction conditions and enhanced selectivity

The solvent-free acetalization of glycerol with acetone was investigated using as catalyst UAV-59, a Coordination Polymer based on nitrilo(trimethylphosphonic acid) and Gd3+, at 25 °C and 55 °C, with various glycerol/acetone (Gly/Ace) molar ratios. The reaction yielded solketal, a five-membered acetal, and 2,2-dimethyl-1,3-dioxan-5-ol, a six-membered acetal. UAV-59's catalytic activity was influenced by temperature, with the highest conversion (94%) achieved at 55 °C, a 1/10 Gly/Ace ratio, and 5% catalyst. The selectivity for solketal remained consistent (95–98%) across all conditions. Reaction kinetics and selectivity profiles were compared, catalyst stability was assessed, and results were benchmarked against Metal Organic Framework catalysts from the literature. The heterogeneous nature of catalysis was confirmed through leaching tests, and the catalyst's chemical features were analyzed using ATR FT-IR spectra and X-ray diffraction patterns, indicating that UAV-59's crystalline structure was preserved during the reaction.

Efficient Synthesis of Solketal from Glycerol and Acetone Catalyzed by FeCl3 /γ‐Al2O3**

AbstractThe porous spherical alumina (γ‐Al2O3) as catalyst support was prepared by sol‐gel method, and FeCl3/γ‐Al2O3 materials were prepared by impregnation method. The FeCl3/γ‐Al2O3 materials were used as catalyst in the Solketal production process by acetalization of acetone and glycerol, showing considerable catalytic performance. When the molar ratio of glycerol and acetone was 1 : 10, 0.2 mol% FeCl3/γ‐Al2O3 was used as the catalyst, and the reaction was carried out at 25 °C for 30 min, the conversion of glycerol was 99.89 %, the selectivity of Solketal was 98.36 %, and the yield of Solketal reached 98.25 %. The mechanism is due to the spherical γ‐Al2O3 support has high thermal stability, large specific surface area, and rich pore structure, encouraging abundant active sites and high catalytic activity of FeCl3 for the acetalization reaction. Thereafter, the experimental results prove that the prepared FeCl3/γ‐Al2O3 catalyst can be easily recovered and reused many times, indicating its great value for large‐scale research and application in the future.

Theoretical Analysis of Simulated Moving Bed Reactor for Rapid Reversible Acetalization of Glycerol with Acetone to Synthesize Solketal

Theoretical Analysis of Simulated Moving Bed Reactor for Rapid Reversible Acetalization of Glycerol with Acetone to Synthesize Solketal

The role of oxygen vacancies in TT-Nb2O5 nanoparticles for the photoconversion of glycerol into solketal

Defect engineering of Nb2O5 nanoparticles is an approachable way to improve photocatalytic performance. TT-Nb2O5 nanoparticles were synthesized using the Pechini method followed by calcination, producing line defects in the crystalline structure and single-electron-trapped oxygen vacancies (SETOVs). The structural results demonstrate that TT-Nb2O5 calcined at 500 °C presents a superlattice orthorhombic structure with a specific surface area between 45 and 90 m2 g−1 and mesoporous network structure. Electronic properties analysis revealed that the TT-Nb2O5 nanoparticles synthesized by the Pechini method (NbPEG and NbEG) have different concentrations of SETOVs in their structure according to the polymerizing agent used in the synthesis, ethylene glycol and polyethylene glycol for NbEG and NbPEG, respectively. The unprecedented photochemical acetalization of glycerol into solketal, employing isopropyl alcohol instead of acetone, was described. The textural properties and the higher concentration of SETOVs significantly improved the photocatalytic performance of NbEG, allowing a synergistic dual catalytic behavior, where the electron accumulation process on the surface of the semiconductor took place, inducing proton generation, which improved the conversion of glycerol (47.8%) as well as the selectivity to solketal (69.8%).

An Evaluation of Glycerol Acetalization with Benzaldehyde over a Ferromagnetic Heteropolyacid Catalyst

Tungstophosphoric acid (H3PW12O40) supported on silica-coated magnetite nanoparticles has been prepared and used as a heterogeneous acid catalyst (Fe3O4@SiO2@HPW) in the condensation of benzaldehyde (B) with glycerol (Gly) for the production of cyclic acetals. Physicochemical techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectrometry (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and N2 physisorption were used to characterize the prepared catalyst. The effect of glycerol/benzaldehyde molar ratio (1/1 to 1/1.2), temperature (80–120 °C), and catalyst amount (1–5%) on glycerol conversion and the selectivity in main reaction products: benzoic acid, 2-phenyl-1,3-dioxolan-4-yl)methanol, 2-Phenyl-1,3-dioxan-5-ol, 2-phenyl-1,3-dioxolane, and methyl 2-hydroxy-3-phenylpropanoate was studied to evaluate the catalytic activity of the prepared Fe3O4@SiO2@HPW catalyst. The optimization of these process parameters was conducted using Box–Behnken design (BBD). Using the BBD methodology, the optimal parameters (120 °C, 1:1.15 glycerol: benzaldehyde, 5% catalyst) were determined, for a glycerol conversion of and cyclic acetals yield of 85.95% and 78.36%, respectively. The catalyst also exhibits excellent activity for glycerol acetalization with other aromatic aldehydes such as cinnamaldehyde, p-methyl-benzaldehyde, p-hydroxy-benzaldehyde, and vanillin.

Heteropoly Ionic Liquid Functionalized MOF-Fe: Synthesis, Characterization, and Catalytic Application in Selective Acetalization of Glycerol to Solketal as a Fuel Additive at Room Temperature, Solvent-Free Conditions

Heteropoly Ionic Liquid Functionalized MOF-Fe: Synthesis, Characterization, and Catalytic Application in Selective Acetalization of Glycerol to Solketal as a Fuel Additive at Room Temperature, Solvent-Free Conditions

Green synthesis of spherical mesoporous SBA-16 and its supported Fe2O3- ZrO2 catalyst for selective acetalization of glycerol to dioxolane as biofuel additive

Acid catalyzed acetalization of glycerol to fuel additive is an important valorization for the available surplus glycerol arising due to ever increasing biodiesel production. For this reaction, mesoporous spherical SBA-16 was synthesized first time from bamboo leaf ash derived sodium silicate (BLASS) and impregnated with 10 wt% each of Fe and Zr, characterized by XRD, N2 adsorption-desorption, SEM-EDX, TEM, NH3 TPD, XPS and evaluated for the acetalization of glycerol with furfural. The crystalline and pore structure of SBA-16 (BLASS) support were not altered by the impregnated Fe and Zr which formed α-Fe2O3 and monoclinic ZrO2 respectively on its surface. Fe2O3 and ZrO2 impregnated spherical SBA−16 (BLASS) gave higher glycerol conversion and dioxalane selectivity compared to the same impregnated on shapeless SBA-16, synthesized from tetraethyl orthosilicate (TEOS), confirmed the positive influence of spherical morphology. Further it retained the activity and selectivity for five recycles. Prolonged reaction time transformed kinetically favored dioxolane to thermodynamically stable dioxane based on which plausible reaction mechanism was proposed. Optimum temperature, glycerol: furfural feed molar ratio, amount of catalyst and reaction time were found to be 100 °C, 1:1, 3.6 wt% of glycerol and 3 h respectively for the maximum glycerol conversion with the highest dioxolane selectivity. Glycerol conversion and dioxolane selectivity for acetalization of glycerol with para substituted benzaldehydes were less than benzaldehyde due to steric effect. Dioxalane selectivity decreased with increase in size of aldehydes due to inductive effect while the cyclic ketones were more reactive for the acetalization of glycerol.

Application of Steapsin lipase for bioconversion of glycerol acetates from glycerol

This work demonstrates the synthesis of glycerol acetate esters derived from glycerol through an esterification reaction catalyzed by lipase (Steapsin). Glycerol was esterified with acetic acid. The best conditions for the synthesis of glycerol acetates were 70 °C, molar ratio between glycerol and acetic acid was 1:10 and the catalyst concentration was 5 wt %. Glycerol (G) conversion reached 95–99% within 48–108 h of reaction. The yields of glycerol acetates were 22%, 59% and 19% of mono glycerol acetate (MGA), di glycerol acetate (DGA) and tri glycerol acetate (TGA) respectively. The obtained results demonstrated the efficiency of the reaction catalyzed by lipase and the feasibility of this method for the synthesis of glycerol acetates through bio-catalysis. This method of glycerol acetate synthesis was not described in the literature until now, giving this research an innovative edge.

Upgrading catalytic efficiency of activated carbons by tailoring lignocellulosic biomass waste for sustainable conversion of glycerol to solketal

This study introduces a novel strategy for boosting both surface acidic properties and textural features of a series of activated carbons from petiole of Mauritia flexuosa Linnaeus fillius, a lignocellulosic biomass waste. The structure, state and concentration of lignin, cellulose and hemicellulose into the selected precursor underwent a reconfiguration protocol aiming at tunning surface features of the carbons-based catalyst chemically activated with H3PO4. In fact, the modified precursors gave rise to activated carbons that boast surface area of up to 2349 m2.g−1 and total acidity ranging from 2.22 to 3.13 mmol.g−1, making them suitable candidate to promote the conversion of glycerol to solketal. The catalysts were successfully applied in the solvent-free acetalization of glycerol with acetone achieving glycerol conversion higher than 83% (selectivity around 98% toward solketal) with remarkable turnover frequencies as well as a notable reusability in consecutive runs. Further, it was noticed that the diversity of acid strength of the reactive sites played an important role in each step of the reaction mechanism synergically improving catalytic performance. The physicochemical and surface chemistry properties of the activated carbons were characterized by means of N2 adsorption/desorption isotherms, thermal analysis, elemental analysis, surface functional groups titration, X-rays diffraction, scanning electron microscopy and FTIR spectroscopy.

Designed synthesis of nanostructured ZrO2 as active support for glycerol valorization reaction

Designed synthesis of nanostructured ZrO 2 as support for glycerol valorization reaction was investigated. The nanocasting route was used to obtain the ZrO 2 support possessing well-dispersed Cu and Zn nanoparticles. The solids were fully characterized by High-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Electron paramagnetic resonance (EPR), N 2 -physisorption isotherms, Temperature-programmed desorption of ammonia (NH 3 -TPD), Scanning electron microscopy coupled to energy dispersive spectroscopy (SEM-EDS) and Fourier transform infrared (FTIR) spectroscopy measurements. The resultant CuZn/ZrO 2 catalyst presented here was distinguished by its unique mesostructured features and defective sites formation. The promotional effect of Cu nanoparticles on the activity illustrated that the formation of active acid sites of medium to strong strength can be modulated by adding a second metal to the catalyst. All these properties provided active solids for acetalization of glycerol with aldehydes and ketones due to the interaction between the active centers and the nanostructured support. Density functional theory (DFT) calculation showed the most favorable mechanistic route of low energy for biofuel additives production.

Synthesis, structure analysis and catalytic activity of two Ln-coordination polymers containing benzophenone-4,4′-dicarboxylate linker

Two Lanthanide-coordination polymers (Ln-CPs) were synthesized, characterized and used as heterogeneous catalysts for the acetalization of glycerol.

Comparison of two acidophilic sulfidogenic consortia for the treatment of acidic mine water.

Sulfate-reducing bioreactors are a biotechnological alternative for the treatment of acid mine drainage (AMD). In this study, two separate bioreactors with pH and temperature-controlled (Bio I and II) were operated with two different acidophilic microbial consortia to determine their efficiencies in sulfate removal from a synthetic acidic mine water. The bioreactors were operated for 302days in continuous flow mode under the same parameters: fed with a sulfate solution of ∼30mM with a pH of 2.5, the temperature at 30°C, stirred gently at 40rpm and using a continuous stream of nitrogen to help remove the H2S produced in the bioreactor. The glycerol consumption, acetate production, and sulfate removal were monitored throughout the course of the experiment. The community composition and potential metabolic functional groups were analyzed via 16S rRNA partial gene sequencing. Bio I consortium reduced the sulfate, achieving a range of sulfate concentration from 4.7 to 19mM in the effluent liquor. The removal of sulfate in Bio II was between 5.6 and 18mM. Both bioreactors' communities showed the presence of the genus De sulfosporosinus as the main sulfate-reducing bacteria (SRB). Despite differences in microbial composition, both bioreactors have similar potential metabolism, with a higher percentage of microorganisms that can use sulfate in respiration. Overall, both bioreactors showed similar performance in treating acidic mine water containing mostly sulfate using two different acidophilic sulfidogenic consortia obtained from different global locations.

Easy and Fast Production of Solketal from Glycerol Acetalization via Heteropolyacids.

This work presents an effective and fast procedure to valorize the main waste produced from the biodiesel industry, i.e., the glycerol. The acetalization of glycerol with acetone represents an effective strategy to produce the valuable solketal, a fuel additive component. In this work, the catalytic efficiency of different commercial heteropolyacids (HPAas) was compared under a solvent-free system. The HPAs used were H3[PW12O40] (PW12), H3[PMo12O40] (PMo12) and H4[SiW12O40] (SiW12). The influence of reactional parameters such as reactants stoichiometry, catalyst concentration and reaction temperature were investigated in order to optimize experimental conditions to increase cost-efficiency and sustainability. HPAs demonstrated to be highly efficient for this type of reaction, presenting a high and fast glycerol conversion, with high selectivity to solketal under sustainable conditions (solvent-free system and room temperature medium). The activity of HPAs using 3% to glycerol weight and a glycerol/acetone ratio of 1:15 followed the order: PW12 (99.2%) > PMo12 (91.4%) > SiW12 (90.7%) as a result of the strong acidic sites after 5 min. In fact, only 5 min of reaction were needed to achieve 97% of solketal product in the presence of the PW12 as a catalyst. This last system presents an effective, selective and sustainable catalytic system to valorize glycerol.