Acidic Exchange Resin Research Articles

Selective epoxidation of natural triglycerides using acidic ion exchange resin as catalyst

ABSTRACTEpoxidation is a very useful reaction in organic synthesis. Due to the high reactivity of the epoxide group it can be used as an active intermediate for the synthesis of many high‐value products. Epoxides are commercial products and they have many industrial uses. Understanding the kinetics of epoxidation reactions can lead to production of value‐added products from locally available renewable natural resources. This research investigated the kinetics of epoxidation of cottonseed oil by peroxyacetic acid (PAA) generated in situ from hydrogen peroxide and glacial acetic acid (AA) in the presence of acidic ion exchange resin (AIER) catalysts, namely Amberlite IR‐120. The effect of several variables including temperature, stirring speed, catalyst loading, and particle size, concentration of hydrogen peroxide and AA on oxirane conversion was studied. A satisfactory level of oxirane conversion (greater than 65%) with high selectivity (greater than 90%) could be obtained if the epoxidation was carried out at optimum conditions, using in situ generated PAA. The Langmuir–Hinshelwood–Hougen–Watson (L–H–H–W) kinetic model approach has been adopted for the development of overall reaction rate equations, and the proposed kinetic model includes the major side reactions for the estimation of kinetic parameters. Kinetic parameters were estimated by fitting experimental data using a nonlinear regression method. From the estimated kinetic constants, the activation energy for the AIER catalysed epoxidation of cottonseed oil was found to be 10.1 kcal mol−1. Copyright © 2010 Curtin University of Technology and John Wiley & Sons, Ltd.

Experimental study and model of reaction kinetics of heterogeneously catalyzed methylal synthesis

Reaction kinetics of the heterogeneously catalyzed formation of methylal from aqueous methanolic formaldehyde solutions are studied in a plug flow reactor at 323, 333 and 343K using the acidic ion exchange resin Amberlyst 15 (Rohm and Haas) as catalyst. Parameters of an activity-based pseudo-homogeneous reaction kinetic model are fitted to the experimental results. The model is based on the true speciation in the reacting solution and explicitly includes the oligomerization reactions of formaldehyde in aqueous methanolic solutions. The reaction kinetic model describes the experimental data well and is suited for process simulations in which both chemical reactions and phase equilibria have to be described simultaneously.

Quantifying temperature and flow rate effects on the performance of a fixed-bed chromatographic reactor

Chromatographic reactors are based on coupling chemical reactions with chromatographic separation in fixed-beds. Temperature and flow rate are important parameters for the performance of such reactors. Temperature affects mainly adsorption, chemical equilibria, mass transfer and reaction kinetics, whereas flow rate influences residence time and dispersion. In order to evaluate the mentioned effects, the hydrolysis reactions of methyl formate (MF) and methyl acetate (MA) were chosen as case studies. These reactions were performed experimentally in a lab-scale fixed-bed chromatographic reactor packed with a strong acidic ion exchange resin. The chosen reactions can be considered to represent a relative fast (MF) and a relative slow (MA) reaction. The processes which take place inside the reactor were described and simulated using an isothermal equilibrium dispersive model. The essential model parameters were determined experimentally at different temperatures and flow rates. The performance of the chromatographic reactor was evaluated at several discrete constant temperature levels by quantifying product purity, productivity and yield. The work provides insight regarding the influence of temperature and flow rate on values of the model parameters and the performance criteria.

Glycerol acetals, kinetic study of the reaction between glycerol and formaldehyde

The acetalization reaction between glycerol and formaldehyde using Amberlyst 47 acidic ion exchange resin was studied. These acetals can be obtained from renewable sources (bioalcohols and bioalcohol derived aldehydes) and seem to be good candidates for different applications such as oxygenated diesel additives. A preliminary kinetic study was performed in a batch stirred tank reactor studying the influence of different process parameters like temperature, feed composition and the stirring speed. A pseudo homogenous kinetic model able to explain the reaction mechanism was adjusted. Thus, the corresponding order of reaction was determined. Amberlyst 47 acidic ion exchange resin showed a fairly good behavior allowing 100% of selectivity towards acetals formation. However, the studied acetalization reaction showed high thermodynamic limitations achieving glycerol conversions around 50% using a stoichiometric feed ratio at 353 K. The product is a mixture of two isomers (1,3-Dioxan-5-ol and 1,3-dioxolane-4-methanol) and the conversion of 1,3-dioxolane-4-methanol into 1,3-Dioxan-5-ol was also observed. ► The reaction between glycerol and acetaldehyde shows thermodynamic limitations. ► Amberlyst 47 ion exchange resins show 100% of selectivity. ► A pseudo-homogeneous kinetic model is able to predict the reaction progress. ► Isomerization reactions were observed from dioxalanes to dioxanes.

Utilization of green seed canola oil for in situ epoxidation

Green seed canola oil is underutilized for edible purposes due to its high chlorophyll content, which makes it more susceptible to photo-oxidation and ultimately reduces the oxidation stability. The present work is an attempt to compare the kinetics of epoxidation of crude green seed canola oil (CGSCO) and treated green seed canola oil (TGSCO) with peroxyacids generated in situ in presence of an Amberlite IR-120 acidic ion exchange resin (AIER) as catalyst. Among the two oxygen carrier studied, acetic acid was found to be a better carrier than the formic acid, as it gives 8% more conversion of double bond than the formic acid. A detailed process developmental study was then performed with the acetic acid/AIER combination. For the oils under investigation parameters optimized were temperature (55°C), hydrogen peroxide to double bond molar ratio (2.0), acetic acid to double bond molar ratio (0.5), and AIER loading (15%). An iodine conversion of 90.33, 90.20%, and a relative epoxide yield of 90, 88.8% were obtained at the optimum reaction conditions for CGSCO and TGSCO, respectively. The formation of the epoxide product of CGSCO and TGSCO was confirmed by Fourier Transform IR Spectroscopy (FTIR) and NMR (1H NMR) spectral analysis.

Pictet-Spengler Reaction Using Ion-Exchange Resin as a Catalyst and Support for ‘Catch and Release’ Purification

The Pictet-Spengler reaction between tryptamine and aldehydes was catalyzed by Dowex 50W-X4 acidic ion-exchange resin. The products were obtained from the resin in high purity by 'catch and release' without the need for separate chromatographic purification.

Synthesis of dimethyl ether (DME) by catalytic distillation

The intrinsic kinetics of liquid phase catalytic dehydration of methanol to dimethyl ether over a macroporous sulphonic acid ion exchange resin was determined in a fixed-bed micro-reactor in the temperature range of 391–423 K and pressures up to 2.0 MPa. The kinetic model based on Eley–Rideal mechanism, as well as the power-rate law model, was adopted for fitting the experimental data. However, the Langmuir–Hinshelwood mechanism is not feasible for describing the dehydration reaction of methanol, as deduced from the macroscopic kinetic data and/or no dependence of methanol conversion on initial methanol concentration in the absence of water at the inlet using acetone as inert solvent. Moreover, an improved process consisting of the combination of a fixed-bed reactor and a catalytic distillation column for the synthesis of DME (Process A) was proposed, and a mathematical model was established, into which the intrinsic kinetics obtained in this work was incorporated. The comparison of operating performance among the improved process, Process B consisting of a fixed-bed reactor and two ordinary distillation columns, and Process C consisting of a catalytic distillation column and an ordinary distillation column was also made. It was found that the improved process is more promising than others in energy consumption, production capacity and column number under the same product purity, and is easy to be implemented based on Process B that is currently used in the actual industrial plants with a long catalyst lifetime.

Biocatalytic Regioselective Oxidation of N-Hydroxyethyl Glucamine for Synthesis of Miglitol

N-2-hydroxyethyl-glucamine (NHEG) was converted into 6-deoxy-6-hydroxylethyl-amino-L-sorbose (DHES) by the regioselective oxidation of Gluconobacter oxydans, and then the generated intermediate of this process was produced to N-hydroxyethyl-deoxynojirimycin (Miglitol) by reductive ring closure reaction. Regioselective oxidation reaction was catalyzed by the high activity sorbitol dehydrogenase of Gluconobacter oxydans biomass which was obtained in preliminary studies. Reductive ring closure reaction was carried out under the conditions of 10%Pd/C as catalyst, at 45~55°C and 0.6MPa of hydrogen. Reaction mixture by the separation and purification of strong acidic exchange resin column has been the Miglitol. In addition, the structure and properties of synthetic product was characterized by thin layer chromatography (TLC), melting point, mass spectrometry (MALDI-MS), Fourier transform infrared spectroscopy (FTIR) analysis. The results showed that the miglitol yield is 77.3%.The regional specificity of the high activity sorbitol dehydrogenase of Gluconobacter oxydans has been verified. Moreover, combinating the technology of the Pd/C- catalyzed reductive ring closure reaction, an effective synthesis process of miglitol is achieved.

Supported ionic liquid silica nanoparticles (SILnPs) as an efficient and recyclable heterogeneous catalyst for the dehydration of fructose to 5-hydroxymethylfurfural

Supported ionic liquid nanoparticles (SILnPs) having particle size ranging from 293 ± 2 to 610 ± 11 nm have been prepared by immobilization of ionic liquid, 1-(tri-ethoxy silyl-propyl)-3-methyl-imidazolium hydrogen sulfate (IL-HSO4) on the surface of silica nanoparticles. The catalytic activity of the prepared SILnPs was investigated for the dehydration of fructose to 5-hydroxymethylfurfural (HMF) in the presence of dimethylsulfoxide (DMSO) as a solvent. The reaction temperature and amount of catalyst have been optimized for dehydration of fructose over SILnPs using experimental design leading to 99.9% fructose conversion and 63.0% HMF yield using silica SILnPs (d = 610 ± 11) nm at 130.0 °C in 30 min reaction time. The SILnPs catalysts developed in this study present improved performances over other zeolites and strong acid ion exchange resin catalysts, and they have been efficiently and very easily recycled over seven times without any significant loss in fructose conversion and HMF yield.

IDENTIFYING THE PLANT ORIGIN OF ARTISTS' YELLOW LAKE PIGMENTS BY ELECTROSPRAY MASS SPECTROMETRY

Dyes containing flavonoids are found in yellow lake pigments used as artists' materials. Pre-treating a sample of a flavonoid-based lake pigment with an acidic ion exchange resin followed by reversed-phase HPLC electrospray mass spectrometry enables the identification of key diagnostic yellow compounds, even when the pigment is bound in paint media. Reference raw plant materials of weld and buckthorn berries were also treated similarly for comparison with the lake pigments derived from these plants. This method is suitable for microsamples and thus suitable for analysis of samples that can be ethically removed from works of art in the course of their conservation. The flavonoid content is analysed and plant origins are suggested for yellow lake samples taken from Reclining Tiger by Jean-Baptiste Oudry and the 1893 version of The Scream by Edvard Munch.

Heterogeneous reactive extraction for secondary butyl alcohol liquid phase synthesis: Microkinetics and equilibria

The reaction kinetics for the liquid phase synthesis of a racemic mixture of the secondary butyl alcohols (SBA) from linear butene isomers (1-butene (1B); cis-2-butene ( c2B); trans-2-butene ( t2B)) and water (W) using a macroporous sulfonic acid ion exchange resin as catalyst were determined experimentally in a multiphase CSTR in the temperature range 39–433 K at 6–8 MPa. This range of pressures is necessary to dissolve butenes in the aqueous phase and to ensure a liquid state of all components. For temperatures higher than 423 K the reaction kinetics for the used catalyst size are influenced by mass transfer resistances within the catalyst matrix. The reaction takes place in the water swollen gel phase of the catalysts microspheres. Due to the large excess of water in the gel phase the compositions in the gel phase, in the macropore fluid, and in the catalyst surrounding aqueous phase are assumed to be identical. According to the literature the reaction is rather catalyzed by hydrated acid protons ( specific catalysis) than by polymer-bonded-SO 3H groups ( general catalysis). The experimental results can therefore be described sufficiently by a pseudo-homogeneous 3-parameter rate expression in aqueous phase activities. The forward reaction is first-order in butene. The reverse reaction is first-order in secondary butyl alcohol. The activation energy was determined to be 108 kJ/mol. Practically no pressure dependence could be observed for pressures exceeding 6 MPa. The ever-present isomerization of the linear butenes on acid catalysts was found to be remarkably faster than the hydration of butenes to SBA. Therefore, the isomerization is considered to be always in equilibrium during the olefin hydration. The formation of the possible by-product di- sec-butyl ether (DSBE) was never observed to a measurable extent. Simultaneous chemical and phase equilibria were investigated theoretically using the volume translated Peng–Robinson equation of state (VTPR-EoS) in combination with a g E -mixing rule. Parameters of the used g E -model were adjusted to experimental ternary liquid–liquid equilibrium (LLE) data.

Biobased Epoxidized Vegetable Oils and Its Greener Epoxy Blends: A Review

Epoxidized vegetable oils (EVO) have drawn much attention in recent years, especially in the polymer industry as they are economical, available, environmentally friendly, non-noxious and renewable. Vegetable oils can be transformed into useful polymerizable oxygenated monomers commonly by Prileshajev-epoxidation, catalytic epoxidation using acidic ion exchange resin, chemo-enzymatic epoxidation, or metal-catalyzed epoxidation. Among those epoxidation methods, chemo-enzymatic epoxidation has achieved considerable interest nowadays since this method is safe, environmentally friendly and conversion rate of epoxidation usually exceeds 90%. Bio-based epoxidized vegetable oils from renewable natural resources are potential green materials to partially substitute and toughen petrochemical-based polymers.

Preparation of bicyclic boroxazolidones from aziridine-2-carboxylic esters

Aziridine-2-carboxylic esters 1 were converted into bicyclic boroxazolidones 3 in a three-step sequence. First, the ester groups were hydrolyzed either by sodium hydroxide or with lithium hydroxide in methanol. The salts thus obtained were acidified with acetic acid or through a weakly acidic ion-exchange resin. Treatment of the zwitterionic aziridine-2-carboxylic acids 2 with triethyl-borane in hexane gave boroxazolidones 3 in high yields. Boroxazolidone 3g, obtained from optically active 1g was reconverted to the starting material by 8-hydroxyquinoline without any loss of optical activity.

Investigation of the Oligomerization of Light Olefins on Ion Exchange Resin Catalyst

The requirements against the quality of motor fuels were rendered more rigorous in the past decade; the most important ones were the major reductions of the sulphur and aromatic content. Besides the changing of the regulation of the motor fuels, the harmful material emission of the Otto- and Diesel-engine built vehicles was also limited significantly. These effects make necessary the greater use of the environmentally friendly, relatively “clean burning”, technically heteroatom- and aromatic free, great n- and i-paraffinic containing blending components in the case of gasoline and diesel gas oils. During our experimental work we studied the possibilities of producing motor fuel blending components like these blending components with the oligomerization of the olefin content of light FCC-naphtha – assuming later industrial application – on Amberlyst-15 acidic ion exchange resin type catalyst. This topic is very important in a modern oil refinery, because different isoparaffin-rich motor fuel blending components can be produced (depending on the catalyst and the process parameters), and this technology can grow considerably the gasoline- and diesel gas oil flexibility of the oil refinery, too. The aim of our experiments was to produce motor fuel blending components with the oligomerization of C4-C6 olefins in light FCC-naphtha matrix. Working on the acidic ion exchange resin catalyst under different process parameters (T: 80–130 °C, P: 15–30 bar, LHSV: 0.5–3.0 h-1) we determined that in the studied process parameter range in preferable case (T: 100–110 °C, P: 25–30 bar, LHSV 0.5–1.0 h-1) the liquid product yield was: greater than 95%, the conversion of olefins: 90–92%, the selectivity of C8-C11: 70–76%, while the selectivity of C12+: 24–30%.

ChemInform Abstract: Dithioacetalization Catalyzed by an Acidic Ion-Exchange Resin.

ChemInform Abstract: Dithioacetalization Catalyzed by an Acidic Ion-Exchange Resin.

Application of Phase-Trafficking Methods to Natural Products Research

A novel simultaneous phase-trafficking approach using spatially separated solid-supported reagents for rapid separation of neutral, basic, and acidic compounds from organic plant extracts with minimum labor is reported. Acidic and basic ion-exchange resins were physically separated into individual sacks ("tea bags") for trapping basic and acidic compounds, respectively, leaving behind in solution neutral components of the natural mixtures. Trapped compounds were then recovered from solid phase by appropriate suspension in acidic or basic solutions. The feasibility of the proposed separation protocol was demonstrated and optimized with an "artificial mixture" of model compounds. In addition, the utility of this methodology was illustrated with the successful separation of the alkaloid skytanthine from Skytanthus acutus Meyen and the main catechins and caffeine from Camellia sinensis L. (Kuntze). This novel approach offers multiple advantages over traditional extraction methods, as it is not labor intensive, makes use of only small quantities of solvents, produces fractions in adequate quantities for biological assays, and can be easily adapted to field conditions for bioprospecting activities.

Basic Ion Exchange Resins as Heterogeneous Catalysts for Biodiesel Synthesis

Basic and acidic ion exchange resins were used as catalysts for the synthesis of biodiesel from soybean oil and methanol. The impact of reaction parameters like molar methanol/oil relationship, catalyst mass and reaction temperature were studied. The catalysts did not show deactivation and the reaction medium remained neutral. The performance of the resins was compared against reference catalysts (NaOH; MgO). A strongly basic macroporous resin was the most active catalyst and it was possible to reach 100 % selectivity to methyl esters. A series reaction mechanism was consistent with the evolutions of the intermediate reaction products.

Development of a Strong Acid Ion Exchange Resin with a Monolithic Microhoneycomb Structure Using the Ice Templating Method

In this work, the synthesis of a strong acid ion-exchange resin with a monolithic microhoneycomb structure was attempted using the ice templating method, a new micromolding technique developed by the authors. The obtained monoliths were found to have micrometer-sized straight channels, and the thickness of the walls which form the channels were also in the micrometer range. Through titration experiments, it was confirmed that the monoliths have a sufficient ion exchange capacity and strong acidity. The monoliths also showed catalysis in esterification reactions which indicates that they can be used as an effective solid acid catalyst with an extremely low hydraulic resistance in various commercial reactions.

Syntheses of 5-hydroxymethylfurfural and levoglucosan by selective dehydration of glucose using solid acid and base catalysts

Selective dehydration of glucose, the most abundant monosaccharide, was examined using a solid acid catalyst individually or a combination of solid acid and base catalysts to form anhydroglucose (levoglucosan) or 5-hydroxymethylfurfural (HMF), respectively. Glucose was dehydrated to anhydroglucose by acid catalysis in polar aprotic solvents including N, N-dimethylformamide. Amberlyst-15, a strongly acidic ion-exchange resin, functioned as an efficient solid acid catalyst for anhydroglucose production with high selectivity. In the presence of solid base, aldose–ketose isomerization of glucose to fructose preferentially occurred by base catalysis, even in coexistence with the solid acid, resulting in successive dehydration of fructose to 5-hydroxymethylfurfural by acid catalysis with high yield in a one-pot reaction. A combination of Amberlyst-15 and hydrotalcite, an anionic layered clay, afforded high HMF selectivity under a moderate reaction temperature, owing to prevention of anhydroglucose formation.

Removal of Co(II) from aqueous solutions by NKC-9 strong acid resin

A strong acidic ion exchange resin (NKC-9) was used as a new adsorbent material for the removal of Co(II) from aqueous solutions. The adsorption isotherm follows the Langmuir model. The maximum adsorption capacity of the resin for Co(II) is evaluated to be 361.0 mg/g by the Langmuir model. It is found that 0.5 mol/L HCl solution provides effectiveness of the desorption of Co(II) from the resin. The adsorption rate constants determined at 288, 298 and 308 K are 7.12×10 −5, 8.51×10 −5 and 9.85×10 −5 s −1, respectively. The apparent activation energy ( E a) is 12.0 kJ/mol and the adsorption parameters of thermodynamic are Δ H Θ =16.1 kJ/mol, Δ S Θ=163.4 J/(mol·K), Δ G Θ 298 K=-32.6 kJ/mol, respectively. The adsorption of Co(II) on the resin is found to be endothermic in nature. Column experiments show that it is possible to remove Co(II) ions from aqueous medium dynamically by NKC-9 resin.