Acidic Exchange Resin Research Articles

Nitration of Benzene to Nitrobenzene Using NO2 as Nitro Source Under Mild and Solvent‐Free Conditions

AbstractIn this work, a green and efficient method has been developed to catalyze the nitration of benzene to nitrobenzene in NO2‐O2 system by using acidic ion exchange resin as catalyst under mild (0 °C and atmospheric pressure) and solvent‐free conditions. Based on experimental screening, commercial acid ion exchange resin Amberlite FPC3500 was identified as the optimal catalyst. Under the optimized reaction conditions, 99.9 % conversion of benzene was obtained with 99.1 % selectivity of nitrobenzene. Furthermore, the catalyst is easily reusable. The results demonstrate a greener route for the production of nitrobenzene.

Ultrasound-assisted synthesis of methyl acrylate using Amberlyst-15 catalyst: optimization using response surface method

Ultrasound-assisted synthesis of methyl acrylate was performed in a solvent-free ultrasound batch reactor using acid ion exchange resin (amberlyst-15) as a heterogeneous catalyst. Influence of different reaction parameters such as temperature (40-70°C), alcohol to acid mole ratio (2-8), catalyst loading (0-10 % w/w), and addition of molecular sieves (0-8%), ultrasound power (0-120W), and duty cycle (20-80%) on the activity of reaction were investigated through one parameter at a time. Further, four significant parameters were optimized using response surface methodology using a central composite design. The maximum conversion of acrylic acid 61.02 %, was obtained at optimum reaction conditions at 61°C reaction temperature, 6.5 alcohol to acid mole ratio, 7.85% catalyst loading, and 60% ultrasound duty cycle. The equilibrium conversion improved from 29.2% to 61.02%, with a significant decrease in reaction time as compared to the conventional approach.

Production of esters with numerous applications: Kinetics of Dowex 50W catalyzed transesterification of methyl acetate with three‐ and four‐carbon structured alcohols

AbstractIn this investigation, a strongly acidic exchange resin was used for the transesterification of methyl acetate with n‐propanol, n‐butanol, and iso‐butanol. Kinetic and equilibrium experiments for the three systems were conducted using a temperature‐controlled batch reactor setup. The effects of the following operating parameters on the transesterification were explored: reaction temperature, catalyst loading, and methyl acetate‐to‐alcohol molar ratio. The conversion of the limiting reactant in the reaction mixture increased with increasing reaction temperature, catalyst loading, and varying reactant proportions from 1:1 to other ratios. It was found that excess methyl acetate would result in higher limiting reactant conversion than using excess alcohol with the same initial molar proportionality between the excess and the limiting reactants. It was found that an increase in the chain length of the alcohol and/or branching suppressed the conversion of the reactants owing to steric hindrance. To mathematically correlate the data, several kinetic models were tested, and the Eley–Rideal model was selected. Accordingly, a reaction mechanism was proposed.

A fully bio‐based monomer derived from undecylenic acid, glycerol, and CO2 useful for the synthesis of polyhydroxyurethanes

AbstractUndecylenic acid, glycerol, and CO2 were used as building blocks for obtaining a fully bio‐based carbonated monomer, useful for polyurethanes. The functionality of the monomer was close to 3 cyclic carbonates/mol, located in terminal positions. In a first stage, a synthetic triglyceride was obtained with 99% selectivity by esterification of glycerol and undecylenic acid at 160°C. The triglyceride was then epoxidized using H2O2 and Amberlyst 15 or Amberlite IR‐120 acidic exchange resins at 57°C. The selectivity to epoxide was kept constant at 98% using Amberlite IR‐120. Terminal cyclic carbonates were then inserted through epoxide moieties under mild conditions by the chemical fixation of CO2 at 80°C and 6 MPa in 6 h. A complete conversion was obtained in 6 h reaction while the selectivity to carbonate groups was near to 99% during all the reaction time. An elastomeric polyhydroxyurethane was obtained by aminolysis of the carbonated monomer with ethylenediamine at 70°C, affording a Young's modulus of 22.6 MPa and Tg of −15.2°C. The material showed a good thermal stability below 240°C.

Two-Stage Conversion of Used Cooking Oil to Biodiesel Using Ion Exchange Resins as Catalysts

This study focuses on the development of a novel two-stage (esterification–transesterification) synthesis of biodiesel from used cooking oil (UCO) using ion exchange resins as catalysts. Esterification of the UCO has been conducted using various types of ion exchange resin catalysts. Purolite D5081, a hyper cross-linked resin, showed the best catalytic performance among all the catalysts investigated, with 92% of free fatty acid (FFA) conversion. The transesterification of pre-treated used cooking oil (P-UCO) was carried out sequentially using several acidic and basic ion exchange resin catalysts. In the screening process, the Diaion PA306s catalyst showed the best catalytic performance and was selected for the optimisation study. A triglyceride conversion of ca. 75% was recorded at the optimum reaction conditions (9% (w/w) catalyst loading, 328 K reaction temperature, 18:1 methanol to P-UCO feed mole ratio, and 350 rpm stirring speed). Furthermore, the reusability study of the Diaion PA306s catalyst gave a similar triglyceride conversion after a couple of cycles without losing its catalytic activity. A dry purification technique was found to give the lowest percentage of glycerides and glycerine content and, therefore, was chosen as the best biodiesel purification route.

Selective extraction of heavy metals from sewage sludge via combined process of acid leaching and ion exchange resins adsorption: Optimization and performance evaluation

ABSTRACT Heavy metals (HMs) in sewage sludge (SS) are major obstacles that limit the land application of SS. Although the removal of HMs with acid leaching and cation exchange resins (CER) adsorption has been investigated, neither process alone could meet the simultaneous demand for efficient HMs removal and good preservation of nutrients. In this report, sulfuric acid (H2SO4) and acetic acid (AC) were used to dissolve HMs from the SS, and subsequent CER adsorption was conducted to selectively extract the HMs from acid leachate. With the addition of 5 mmol/L H2SO4, the maximum leaching efficiency of Ni, Cu, Zn and Fe were 64.0%±2.7%, 29.0%±3.7%, 98.4%±4.1% and 16.4%±0.3%, respectively. No significant inhibition effect of Fe in the leachate on the HMs adsorption with CER has been observed. The CER with sulfonate groups (R-SO3H) showed higher Ni, Cu and Zn adsorption efficiency than the CER with thioureido groups (R-SH) and carboxylic groups (R-COOH) in the acid leachate. The optimal operation condition with a combined usage of H2SO4 and R-SO3H is characterized by the advantages of high HM removal efficiency, affordable cost, and low energy consumption through the evaluation with the triangulation model.

Eco friendly synthesis of epoxidized palm oleic acid in acidic ion exchange resin

Abstract Global raw material use has moved from a non-renewable to a renewable resource. Additionally, the research on epoxidation has produced a safer, more cost-effective, and ecologically friendly product than non-renewable resources. At present, there are limited studies on the production of epoxidized palm oleic acid using eco-friendly ion exchange resin method. Consequently, the objective of this study is to optimise the reaction conditions of epoxidation palm oleic acid using ion exchange resin (amberlite IR 120H) as a catalyst. Epoxidized palm oleic acid was prepared using performic acid formed in situ by mixing formic acid with hydrogen peroxide. The results showed that the optimum reaction conditions for the production of oxirane content were a temperature of 75 °C and a hydrogen peroxide concentration of 30%. The maximum relative conversion of palm oleic acid to oxirane was achieved using the optimum conditions with up to 75%. Finally, a mathematical model was developed using MATLAB and the fourth-order Runge–Kutta method was integrated with the genetic algorithm to determine the reaction rate, which was consistent with the experimental data. This study proved that palm oleic acid was successfully converted into a green epoxide that promotes the use of palm oil as a raw material.

An integrated electrolysis-microfiltration-ion exchange closed-loop system for effective water softening without chemicals input and spent regenerant discharge

In this study, an energy-efficient and industrially scalable undivided electrolysis cell featuring the abstraction of H+ from the anode boundary layer was developed to produce acid and alkaline effluents. Then, the electrolysis cell was integrated with microfiltration and ion-exchange (IEMI) for water softening. In this system, CaCO3 crystals could form in the alkaline effluent from the electrolysis cell and then was intercepted by a porous tubular Ti microfilter in the crystallizer, and weak acid ion-exchange resin in H+-form (WAC-H) was used to further remove the hardness content residual in water. The closed-loop operation mode of the IEMI system with zero discharge of spent regenerant could be realized by using the acid effluent abstracted from the electrolysis cell to regenerate the exhausted WAC-H and then introducing the spent regenerant into the feed water for hardness precipitation again in the IEMI system. Specifically, the total hardness could reduce from 400 to 40 mg CaCO3 L−1 with a removal efficiency of 90 % at energy consumption of 1.9 kWh (kg CaCO3)−1 when an optimal current density of 10 mA cm−2 was applied. Overall, the developed IEMI system paved the ground for scaling up the applications of the electrochemical softening technology in various industrial and domestic fields.

Adsorption study on the removal of ciprofloxacin in aqueous solution by an acidic ion exchange resin with bifunctional group

Removal of fluoroquinolone antibiotic pollutants in the aquatic environment has become a research hotspot. In this work, two skeletal resins and four acidic ion exchange resins have been used as adsorbent materials to evaluate their adsorption properties for fluoroquinolone antibiotic ciprofloxacin (CIP) in aqueous solution. Compared with other materials, the sulfonic-phosphoric acid-based bifunctional resin S9570 has shown the best adsorption performance for CIP. The effect of solution pH on the adsorption of CIP by S9570 has been further explored, and the optimal adsorption capacity has been obtained at pH 4.0. The adsorption kinetics and thermodynamics of S9570 for CIP have been investigated in details. The high fits of the pseudo-second-order and intraparticle diffusion equations indicate that these two models can better describe the adsorption process of S9570 for CIP which has been jointly controlled by chemical adsorption and intraparticle diffusion steps and has been accompanied by weak or intermediate initial adsorption behaviour. The best fit results of Langmuir has indicated that there exists a monolayer adsorption on the surface of the S9570.Thermodynamic parameters suggest that the adsorption is an endothermic, spontaneous process with increased randomness at the solid-liquid interface. Through this evaluation of resin adsorption materials, it has been proved that the adsorbent material has good reusability and antiinterference performance.

The role of acetonitrile in the direct synthesis of hydrogen peroxide over palladium supported by ion-exchange resins

Acetonitrile is used as an effective, non-corrosive selectivity enhancer for the direct synthesis of hydrogen peroxide (HP). Palladium catalysts supported by activated carbon or poly-divinylbenzene are poisoned by acetonitrile, which makes them very little productive. Conversely the catalysts supported by strongly acidic ion-exchange resin are much more selective and productive in the presence of acetonitrile, and for relatively long time. TEM shows that the size of their metal nanoparticles can be decreased by a reconstruction process, possibly sustained by leached palladium(II) species. HP decomposition experiments show that acetonitrile inhibits the OO bonds splitting.

Dehydration of levoglucosan to levoglucosenone over solid acid catalysts. Tuning the product distribution by changing the acid properties of the catalysts

The effect of the catalytic properties of various types of solid acids, including oxides (ZrO2, SOX/ZrO2, WOX/ZrO2, Nb2O5, NbOPO4, Al2O3, TiO2), silica–aluminas (ZSM5 and USY zeolites) and acidic ion-exchange resins (Amberlyst-70 and Dowex 50wx8) were investigated for liquid-phase levoglucosan (LGA) conversion. H2SO4 was also evaluated as a reference catalyst. The concentration of both Brønsted and Lewis acid sites in the catalysts was measured by FTIR of adsorbed pyridine and titration with NaOH. The catalysts were tested under different reaction conditions (110–170 °C and 30–60 bar of N2) for 1 h using tetrahydrofuran (THF) as solvent. The product distribution obtained from the LGA conversion can be tuned depending on the type of acid site of the catalyst or the reaction conditions used. Catalysts containing only Bronsted acid sites were selective to LA while those with both Bronsted and Lewis acid sites favored the formation of 5-hydroxymethylfurfural (HMF). LGO was mainly produced by the homogeneous catalyst. The USY and HZM5 (SiO2/Al2O3 ratio of 23) promoted the production of HMF and glucose, respectively. A reaction mechanism was proposed taking into account the acid properties of the catalysts. The reactions of dehydration of LGA to LGO or hydration of glucose requires Brønsted acid sites. Catalysts with only Lewis acid sites produced only humins. For the catalysts containing both Brønsted and Lewis acid sites, LGA is mainly hydrated to glucose on the Bronsted acid sites. Then, glucose is preferentially isomerized to fructose on the Lewis acid sites, followed by its dehydration to HMF. The low LA formation shows that the hydration of HMF to LA requires a higher concentration of Brønsted acid sites.

Synthesis of Methylal and Poly(oxymethylene) Dimethyl Ethers from Dimethyl Ether and Trioxane

Poly(oxymethylene) dimethyl ethers (OME) are interesting synthetic fuels that could replace fossil diesel fuel. Therefore, economic routes for OME production have to be developed. One particularly interesting route is the synthesis of OME from dimethyl ether (DME) and formaldehyde. The principal feasibility of this route is established, but the physico-chemical information on essential steps is still lacking. In particular, there is no data on the first step in this synthesis, which is the formation of methylal (MAL) from DME and formaldehyde. Kinetic batch experiments were carried out in a stirred batch autoclave with a commercially available acidic ion-exchange resin as a catalyst in the temperature range of 353–373 K for up to 200 h. Trioxane was used as a water-free source of formaldehyde. Due to the volatility of DME, the experiments were carried out under pressure; high-pressure magnetic resonance (NMR) spectroscopy was applied for the analysis. During the reaction, not only MAL but also OME are formed, as well as a side product, methyl formate (MeFo). Therefore, the equilibrium constant of the MAL formation had to be determined based on a reaction kinetic model of the entire reaction network. The formation of MAL was found to have a larger equilibrium constant than the subsequent oligomerization reactions leading to OME, but it is also much slower than these reactions.

Xylooligosaccharides Production from Xylan Hydrolysis Using Recyclable Strong Acidic Cationic Exchange Resin as Solid Acid Catalyst.

As the emerging functional food additives, xylooligosaccharides are receiving high commercial interest due to their excellent gut microbiota modulation capacity, and accumulating studies have suggested that acidic hydrolysis for xylooligosaccharides preparation is the most convenient and cost-effective approach, whereas liquid acids are still limited due to the challenges in acid catalysts separation and products recovery. In the present study, a strong acidic cationic resin (NKC-9), as a recyclable solid acid catalyst, was successfully applied to xylooligosaccharides production by acidic hydrolysis of xylan. Additionally, a central composite design with response surface methodology was employed to optimize the conditions for maximizing xylooligosaccharides yields. The results suggested that xylooligosaccharides with the desired degree of polymerization (2-6) could be prepared, and the maximum yield was reached 47.7% in the case of 5% solid acid loading at 131 °C for 42 min. Finally, the recyclability of the solid acid catalysts confirmed that it was a cost-effective strategy for xylooligosaccharides production.

Size Selectivity in the Hydroxylation of Esters of Unsaturated Fatty Acids

AbstractThe one‐pot two‐steps hydroxylation of fatty acid esters with H2O2 and acetic acid catalyzed by acidic ion exchange resins is reinvestigated aiming to shed light on the relationship between the structure of different substrates and the efficiency of different resins in promoting the hydrolysis of the intermediate epoxides to the corresponding diols. 1H‐NMR analysis of crude reaction mixtures highlight a correlation between the drying process of the resins, their cross‐linking degree, and their effectiveness in promoting such a hydrolysis. Employing dry Dowex 50WX2 as a catalyst, a close relationship is found between the steric hindrance of the substrates and the recovered diol/epoxide ratio, with less hindered substrates preferentially leading to the formation of high diol/epoxide ratios. Accordingly, this procedure is successfully applied to the valorization of the methyl ester of a waste cooking oil. Conversions and selectivity kinetics increase significantly when the amount of the catalyst is increased leading to successfully apply this one‐pot two‐steps hydroxylation reaction to esters of unsaturated fatty acids sterically bulkier than methyl oleate. Spectroscopic and morphological characterization of Dowex 50WX2 shows that the drying process and the interaction with the reagents affect the morphology of the catalyst and promotes the hydrolysis of the intermediate epoxides.Practical applications: Hydroxylated fatty acids are valuable intermediates in the synthesis of a variety of useful biochemicals, including mono‐ and di‐carboxylic acids, biolubricants, and cosmetics. Their work describes the successful application to a variety of esters of unsaturated fatty acids and to the methyl esters of a vegetable oil and a waste cooking oil, of a straightforward hydroxylation procedure, catalysed by commercially available acidic ion exchange resins and occurring under mild and easy to set‐up conditions. The evidence reported on the different catalytic activities and on the structural characterization of the as‐received and dried acidic ion exchange resins are of practical importance in their employment as acidic catalysts.

Aquivion perfluorosulfonic superacid as an effective catalyst for selective epoxidation of vegetable oils.

The acid-promoted epoxidation of vegetable oils was studied using a variety of acidic ion exchange resins as heterogeneous acid catalysts. Quantitative and selective epoxidation of a series of vegetable oils with different composition of saturated, mono-, di- and tri-unsaturated fatty acids was obtained upon identification of the more efficient catalyst and experimental conditions. Furthermore, optimized reaction conditions were successfully applied to the epoxidation of a waste cooking oil, thus extending our procedure to the valorization of a biowaste, an area of increasing importance within a more sustainable society. The use of quantitative 1HNMR besides making accurate evaluation of the amounts of reagents to be employed and of the selectivity, allowed facile and rapid quantification of mono-, di- and tri-epoxides, thus providing an indirect indication on the fatty acid composition of the vegetable oils, even in the presence of very low quantities of linolenic acid.

Combination of Two Synchrotron Radiation-Based Techniques and Chemometrics to Study an Enhanced Natural Remineralization of Enamel.

The limitations to assess dental enamel remineralization have been overcome by a methodology resulting from the appropriate combination of synchrotron radiation-based techniques on both, infrared microspectroscopy and micro X-ray diffraction, with the help of specific data mining. Since amelogenin plays a key role in modulating the mineralization of tooth enamel, we propose a controlled ion release for fluorapatite structural ions (Ca2+, PO43–, and F–, also including Zn2+) by using weak acid and weak base ion-exchange resins in the presence of amelogenin to remineralize the surface of etched teeth. This combination provides the necessary ions for enamel remineralization and a guide for crystal growth due to the protein. Remineralized tooth samples were analyzed by applying the indicated methodology. The synchrotron data were treated using principal component analysis and multivariate curve resolution to analyze the mineral layer formed in the presence and absence of amelogenin. The remineralizing treatment created a fluorapatite layer free of carbonate impurities and with a similar orientation to that of the natural enamel thanks to amelogenin contribution.

Epoxidation of Pumpkin Seed Oil (Curcurbita Maxima) using Acidic Ion Exchange Resin and its Kinetic and Thermodynamic Study

Epoxidation of Pumpkin Seed Oil (Curcurbita Maxima) using Acidic Ion Exchange Resin and its Kinetic and Thermodynamic Study

Modeling and gPROMS based simulation of adsorption process for the removal of Cu (II) from aqueous wastewater

The present work studies the performance of Indion 730 (Strong acid) ion exchange resin for the removal of Cu (II). The modeling and gPROMS based simulation is used to study the sorption capacity, equilibrium, and performances of Indion 730 ion exchange resin. The extraction effectiveness of the resin is studied by using breakthrough curves. The experimental and simulation results were compared. A numerical model is proposed for the investigation of the ion exchange phenomenon using gPROMS using various optimized parameters like flow rate, bed height, and initial concentration of wastewater containing Cu (II) heavy metal ion in the column. For instance, the effects of flow rate, bed height, and inlet concentration of heavy metal on a breakthrough curve are investigated in depth. The results illustrate that the predicted theoretical breakthrough curves show analogous patterns with the corresponding investigational output with a discrepancy of the equilibrium time. The predictions of the model will help to discover the optimal conditions of operation.

Adsorption Behavior of Pb, Cd, Ca, Al, Zn And Co Metal Ions on Cation Exchange Resin Dowex 50 Wx8 (Nh4+ Form) From Aqueous Acetone-Ammonium Propionate Media

There has a wide interest in stability of different types of ion exchange resins against ionizing radiations. The irradiation damage and stability of polystyrendigni benzene and phenolformaldehide sulphonic acid ion exchange resins was investigated by determination of the radiolytic gases. The gas analysis showed a very good linear dose dependence of the evolved hydrogen and carbon monoxide. The linearity of carbon dioxide was good for Dowex 50 WX 10 but less pronounce for zeo-carb 215. Sulphur dioxide was at least partially produced by direct action and was consumed by secondary reaction during irradiation. Kuzin et al [1] analysed radiolytic gases evolved from a carboxylic acid exchange resin. Wiely et al [2] investigated gamma radiation induce degradation of sulphonetic styrle resin cross link with 4 and 8 % m / p dinyl benzene isomer or mixtures thereof including commercial divenyle benzene have been shown loss in capacity 5-12. 8% at the radiation intensities of 290 R/hr and total dose 0.91 – 1.0 x 10-8 rad in presence of water.

Effect of formaldehyde precursor and water inhibition in dimethoxymethane synthesis from methanol over acidic ion exchange resins: mechanism and kinetics

AbstractA systematic comparison of the use of trioxane and depolymerized paraformaldehyde as formaldehyde precursors for the acetalization of methanol to dimethoxymethane was performed, using the acidic ion exchange resin, Amberlyst 15, as catalyst. Experiments were carried out under isothermal conditions in batch and continuous fixed‐bed reactors. The influence of the main operating parameters, temperature (80–120 °C), space time (2.7–6.2 kg h m−3), and feed concentration (12–22 wt% of trioxane/formaldehyde, 2.5 wt% of water on methanol) on reaction rate and product selectivity were evaluated. When using trioxane as reactant, dimethoxymethane is the main reaction product, with more than 90% selectivity. The catalyst was found to be stable during all the experiments (more than 30 h on stream). However, water caused a reversible inhibitory effect on reaction rate, which can be accounted for by using a competitive adsorption model. A mechanistic kinetic model was proposed and validated using the experimental results. When trioxane is used as reactant, its decomposition to formaldehyde was found to be the rate‐limiting step of the reaction mechanism (activation energy 73.1 kJ mol−1). This was confirmed with additional experiments, in which trioxane was replaced by depolymerized formaldehyde. In this case, reaction rate considerably increased. © 2021 The Authors. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley & Sons Ltd.