Acidic Exchange Resin Research Articles

Preparative Separation of Cephalosporin with Ion-Exchange Planar Electrochromatography

A novel device for planar electrochromatography was developed, in which an electric field was applied across a thin layer of strongly acidic ion-exchange resin. Three types of cephalosporin – cefamezin, cefotaxime, and cefradine, at preparative amounts, were separated with different mobile phases and applied voltages. Experimental results showed that planar electrochromatography using 0.05 M alanine-acetate solution containing 7.0 M ethanol and 1% Triton X-100 under 200 or 400 V achieved good separation. Critical micelle concentration of Triton X-100 was measured to identify micelle formation in the buffer.

Photodegradation of humic acid using spherical activated carbon contained Zn in a fluidized bed system

In this study, a strong acid ion-exchange resin, as the starting material of spherical activated carbon contained Zn (Zn-SPAC), was treated by 0.1 N zinc solution. Ion-exchange treatment was performed from one to three times for controlling the zinc content. The ion-exchanged resins were activated under N2/H2O vapor atmosphere at 900°C for 0.5 h, followed by carbonization treatment at 700°C under N2 atmosphere. The Zn-SPAC samples were measured for their physicochemical characteristics, such as X-ray diffraction (XRD) patterns, scanning electron microscope (SEM) images, electron probe micro analyzer (EPMA) images, energy dispersive X-ray spectroscopy (EDXS), Brunauer–Emmett–Teller (BET) specific surface area, strength, and zinc content. Also, the samples were used in order to measure photochemical activities, such as the removal efficiency of humic acid (HA) in a fluidized batch reactor. The XRD patterns appeared as the ZnS type. The Zn-SPAC had a large BET specific surface area and their shape was spherical, with a diameter of about 350–400 μm. When the Zn-SPAC was dosed in a fluidized bed reactor with UV light, the HA removal efficiency increased by up to 60%. On the other hand, the HA removal efficiency by only UV-C (λ max = 254 nm) irradiation was very low, about 15%. Therefore, we infer that Zn-SPAC has good photochemical activity and presented the possibility of being a useful photocatalyst for water purification.

Oxygen isotope analysis of phosphate: improved precision using TC/EA CF‐IRMS

Oxygen isotope values of biogenic apatite have long demonstrated considerable promise for paleothermometry potential because of the abundance of material in the fossil record and greater resistance of apatite to diagenesis compared to carbonate. Unfortunately, this promise has not been fully realized because of relatively poor precision of isotopic measurements, and exceedingly small size of some substrates for analysis. Building on previous work, we demonstrate that it is possible to improve precision of delta18O(PO4) measurements using a 'reverse-plumbed' thermal conversion elemental analyzer (TC/EA) coupled to a continuous flow isotope ratio mass spectrometer (CF-IRMS) via a helium stream [Correction made here after initial online publication]. This modification to the flow of helium through the TC/EA, and careful location of the packing of glassy carbon fragments relative to the hot spot in the reactor, leads to narrower, more symmetrically distributed CO elution peaks with diminished tailing. In addition, we describe our apatite purification chemistry that uses nitric acid and cation exchange resin. Purification chemistry is optimized for processing small samples, minimizing isotopic fractionation of PO4(-3) and permitting Ca, Sr and Nd to be eluted and purified further for the measurement of delta44Ca and 87Sr/86Sr in modern biogenic apatite and 143Nd/144Nd in fossil apatite. Our methodology yields an external precision of +/- 0.15 per thousand (1sigma) for delta18O(PO4). The uncertainty is related to the preparation of the Ag3PO4 salt, conversion to CO gas in a reversed-plumbed TC/EA, analysis of oxygen isotopes using a CF-IRMS, and uncertainty in constructing calibration lines that convert raw delta18O data to the VSMOW scale. Matrix matching of samples and standards for the purpose of calibration to the VSMOW scale was determined to be unnecessary. Our method requires only slightly modified equipment that is widely available. This fact, and the demonstrated improvement in precision, should help to make apatite paleothermometry far more accessible to paleoclimate researchers.

Comparison of Novozym 435 and Amberlyst 15 as Heterogeneous Catalyst for Production of Biodiesel from Palm Fatty Acid Distillate

Palm fatty acid distillate (PFAD), a byproduct from the palm oil refinery process, has recently been utilized as an alternative feedstock for biodiesel (BD) production via homogeneous acid-catalyzed esterification. This process suffers from catalyst recovery, wastewater treatment, and BD purification. To minimize the problem, heterogeneous catalysts, Novozym 435 (immobilized Candida antarctica lipase B) and Amberlyst 15 (acidic styrene-divinylbenzene sulfonated ion-exchange resin), are tested and their catalytic activities under various reaction conditions are compared. Novozym 435 acts fast and its optimal specific activity (g BD/h/g catalyst) is 50-fold higher than that of Amberlyst 15. The maximum BD yields obtained using Novozym 435 and Amberlyst 15 are 95 and 97%, respectively. Both catalysts are recycled more than 15 cycles without losing their activities. The results suggest that both Novozym 435 and Amberlyst 15 can be effectively used for BD production from PFAD.

Simple and Efficient Metal-free Hydroarylation and Hydroalkylation Using Strongly Acidic Ion-exchange Resin

Abstract Higly efficient hydroarylation and hydroalkylation of styrenes with various arenes and 1,3-dicarbonyl compounds respectively have been developed using Amberlyst-15 as a heterogeneous catalyst. The excellent yields, short reaction times, and high selectivity are the advantages of this method. The C–H functionalization has been achieved here under metal-free conditions.

Dowex as Reusable Acidic Polymeric Catalyst in the Efficient and Regioselective Conversion of Epoxides into β‐Hydroxy Thiocyanates under Solvent Free Conditions

AbstractA convenient and efficient procedure for the regioselective ring opening of epoxides in the presence of Dowex (strongly acidic cationic exchange resin), as reusable eco‐friendly catalyst under solvent free conditions is described. Thus, several β‐hydroxy thiocyanates, useful intermediates toward pharmaceutical and biologically active molecules, are easily obtained in high isolated yields.

Introduction of bifunctionality into the phosphinic acid ion-exchange resin for enhancing metal ion complexation

In nuclear industry the role of conventional strong cation exchange resins is limited as they function less in high acid media. The phosphorous group that has got more affinity towards actinide elements is chosen as a chelating group and the phosphinic acid ion exchange resin was synthesized. The extraction ability of the phosphinic acid resin for plutonium (Pu) from HNO 3 medium as well as from H 2SO 4 medium was studied. Though the resin shows better extraction for Pu than the strong cation exchanger resins at higher acidities, its kinetics is slow. In order to enhance the kinetics as well as to improve upon selectivity, a sulphonic group is introduced into the phosphinic acid resin. To verify the effect of bifunctionality extraction studies have been carried out with Pu from different acid media of varying concentrations. Sulphonated phosphinic acid resin shows a 2-fold increase in distribution coefficient ( k d ) as well as it reached equilibrium very fast compared to the phosphinic acid resin. It is postulated that the sulphonic acid ligand provides an access mechanism for the metal ions into the polymer matrix while it is the phosphinic acid group that is responsible for selective coordination of metal ions. Thus bifunctionality is coupling of an access mechanism to a recognition mechanism. The experiments carried out demonstrated the applicability of sulphonated phosphinic acid resin in the nuclear industry.

Epoxidation of Canola Oil with Hydrogen Peroxide Catalyzed by Acidic Ion Exchange Resin

AbstractCanola oil with an iodine value of 112/100 g, and containing 60% oleic acid and 20% linoleic acid, was epoxidised using a peroxyacid generated in situ from hydrogen peroxide and a carboxylic acid (acetic or formic acid) in the presence of an acidic ion exchange resin (AIER), Amberlite IR 120H. Acetic acid was found to be a better oxygen carrier than formic acid, as it produced about 10% more conversion of ethylenic unsaturation to oxirane than that produced by formic acid under otherwise identical conditions. A detailed process developmental study was then performed with the acetic acid/AIER combination. The parameters optimised were temperature (65 °C), acetic acid to ethylenic unsaturation molar ratio (0.5), hydrogen peroxide to ethylenic unsaturation molar ratio (1.5), and AIER loading (22%). An iodine conversion of 88.4% and a relative conversion to oxirane of 90% were obtained at the optimum reaction conditions. The heterogeneous catalyst, AIER, was found to be reusable and exhibited a negligible loss in activity.

The synthesis of spherical activated carbons containing zinc and their photochemical activity

Spherical activated carbon (AC) containing photocatalyst was prepared using strong and weak acid ion-exchange resins as starting materials. These resins were treated with an aqueous solution of Zn 2+ or [ Zn ( NH 3 ) 4 ] 2 + and both treated resins and non-treated resins were carbonized and activated. The physicochemical characteristics of the AC samples were examined using XRD, SEM, EDS, BET, EPMA, ESR, compressive strength and zinc content. The photocatalytic activity was evaluated by measuring the humic acid (HA) removal efficiency using UV/photocatalyst system. When strong acid ion-exchange resins (SZ samples) were used to prepare AC containing zinc, the zinc was found to have ZnS crystal structures, whereas in case of the use of weak acid ion-exchange resins (WZ samples), the zinc was found to have ZnO crystal structure. Both the SZ and WZ samples had spherical shape except the WZ-A-900 and had a good BET specific surface area. In the HA removal test using a floating UV/photocatalyst system, the WZ samples showed higher HA removal efficiency than the SZ samples.

Deionization of Coagulated, Clarified, Turbid Gauri Shankar Lake Waters by Using Ion-Exchange Technology

Water collected from a rain fed Gauri Shankar Lake, Bhavnagar, Gujarat, India was used for this study. It was clarified by giving treatment with alum and poly aluminum chloride (PAC) to remove suspended impurities present in it. Waters having turbidity value of 100–750 NTU (Nephelometric Turbidity Units) were treated with PAC and alum. The dosage of PAC required for the treatment was 60% less as compared with alum. The clarified water was passed through columns loaded with strong acid and strong base ion-exchange resins to obtain deionized water. The experiments were carried out for 100 cycles of exhaustion and regeneration. The effect of the coagulation process conditions on ion-exchange capacity, and the physical attrition of the ion-exchange resins were studied intensively. Also, the performance of ion-exchange resins was compared with virgin ground waters from the institute's well. The resins employed in the study were subjected to EDX (Energy Dispersive X-Ray Spectroscopy) analysis to find out the presence of coagulating ions adsorbed on the resins. The resins were also subjected to SEM (Scanning Electron Microscope) analysis to find changes on their surface due to adhering materials if any.

Kinetics Characterization of Ions Release Under Dynamic and Batch Conditions. Strong Acid and Strong Base Type Ion Exchange Resins

The purpose of this study has been to investigate the influence of key parameters (i.e., the structure of the resin organic polymer and its particle size, as well as the temperature of the process) on the release of calcium and fluoride ions from cationic and anionic ion exchange resins of strong character, in order to develop a formulation for a controlled release of the mentioned ions, that are present in organomineral tissues. Kinetics parameters were evaluated under dynamic and batch conditions. It has been observed that the rate of Ca2+ and F− release increases when temperature increases and particle size decreases. Because of the larger pore volumes that provide a greater effective surface area, macroporous ion exchangers observe a higher rate of ions release than those of gel nature. Results obtained in this study are well interpreted by the models based on intraparticle diffusion as rate controlling step of the ion exchange process. The effective rate of release, B (obtained from the application of mentioned models), of the respective ions in the resin phase describes quantitatively the kinetic process. Linear dependences of –log (B) with the resin particles diameters can be applied to the estimation of B values for very low particle size resins, materials commonly used in the development of controlled release formulations.

Reactive Distillation for Two-Stage Reaction Systems: Adipic Acid and Glutaric Acid Esterifications

Two new complete reactive distillation processes for two-stage reaction systems (adipic acid and glutaric acid esterifications with methanol) are explored. Similarities and differences between these two flowsheets have been identified. Both the diacid esterification reactions are catalyzed heterogeneously by an acidic ion-exchange resin, and reaction kinetics can be described using quasihomogeneous model. The UNIFAC method predicts suitable NRTL parameters for calculating liquid activity coefficients, which give a good description of experimental data. Results show that the plantwide flowsheets need a large recycle ratio for the light key reactants and ester products could be achieved with a purity of 99 mol %. A systematic design procedure for the complete flowsheets is presented, and the optimum operating conditions of the overall systems are studied to minimize the total annual cost while meeting the product specifications.

Kinetics Characterization of Ion Release under Dynamic and Batch Conditions. I. Weak Acid and Weak Base Ion Exchange Resins

The aim of the present work is concerned with a study of the kinetics of release of both Ca2+ and F− from the corresponding loaded ion-exchange resins (weak acid and weak base character for Ca2+ for F−, respectively), using both dynamic and batch experimental conditions with an artificial saliva solution as the ion-exchange media at 293 and 310 K. The influence of resin particle size and the temperature were evaluated by the kinetics parameters for the effective rate of release (B) and diffusion coefficient (D). The rate of ion release increases with temperature and decreases with particle size. The experimental data were well fitted by models based on intraparticle diffusion-controlled processes. In dynamic studies, the linear dependence of −log 10(B) with the diameter of the resin particles can be applied for the estimation of B values when resins of low particle size are considered. In batch processes, although resins of low particle size can be studied, a linear relationship was only attained for the case of slow ion-exchange kinetic systems.

Homo- and heterogeneous Ru-based metathesis catalysts in cross-metathesis of 15-allylestrone—towards 17β-hydroxysteroid dehydrogenase type 1 inhibitors

The cross-metathesis of allylestrone with acrylic acid derivatives using homogeneous and heterogenized Ru-catalysts was evaluated for the synthesis of a new 17β-hydroxysteroid dehydrogenase type 1 inhibitor. Hoveyda-type catalyst containing an additional diethylamino group turned out to be comparably active as homogeneous Grubbs II catalyst after immobilization on an acidic ion exchange resin which greatly facilitated workup.

Thermodynamic Equilibrium and Reaction Kinetics for the Esterification of Lactic Acid with Ethanol Catalyzed by Acid Ion-Exchange Resin

The heterogeneous catalysis of lactic acid (88 wt %) esterification with ethanol in the presence of Amberlyst 15-wet was studied for catalyst loading of 1.2−3.9 wt %, initial molar ratio of reactants of 1.1−2.8, and temperature from 50 to 90 °C. In this work a methodology based on the UNIQUAC model was developed to determine the thermodynamic equilibrium constant since in the literature there is inconsistency concerning the temperature dependence of the thermodynamic equilibrium constant. A simplified Langmuir−Hinshelwood kinetic model was used to predict the experimental data. The proposed rate law is r = kc(aEthaLa − aELaW/K)/(1 + KEthaEth + KWaW)2; the kinetic parameters are the preexponential factor, kc,0 = 2.70 × 107 mol·g-1·min-1, and the activation energy, Ea = 49.98 kJ/mol. The equilibrium reaction constant is K = 19.35 exp(−515.13/T (K)) with reaction enthalpy 4.28 kJ/mol. The model reasonably predicts the kinetic experimental data, and it will be very useful to apply to the design and optimizati...

Acetylation of glycerol catalyzed by different solid acids

This work describes the acetylation of glycerol with acetic acid catalyzed by different solid acids. Reactions were carried out in batch mode under reflux. The kinetics of glycerol transformation and selectivity to the products, notably mono, di and triacetyl esters, were determined within 30 min of reaction time to observe the primary products. The results showed that the acid exchange resin, Amberlyst-15, was the most active catalyst, achieving 97% conversion in this period, followed by K-10 montmorillonite, niobic acid, HZSM-5 and HUSY. The selectivity varied for each catalyst and conversion degree, but the yield of di and triacetylated products increased with increasing conversion and reaction time. In all cases, the formation of α-hydroxy-acetone (acetol) was observed and associated with the glycerol dehydration. The poor performance of the zeolites might be related to diffusion problems of the acetylated esters inside the cavities.

Esterification of free fatty acids in waste cooking oils (WCO): Role of ion-exchange resins

Although WCO plays a crucial role for the economical production of biodiesel, free fatty acid (FFA) level in the nature of WCO cause saponification problems during transesterification. Acidic ion-exchange resins can be used to decrease WCO free fatty acid level. In this study, activities of resins (Amberlyst-15 (A-15), Amberlyst-35 (A-35), Amberlyst-16 (A-16) and Dowex HCR-W2) in direct FFA esterification were examined in the temperature range of 50–60°C and the effect of catalyst amount (1–2wt%) on FFA conversion was also analyzed. FFA conversion increased with increasing reaction temperature and catalyst amount. Order of catalytic activities was found as A-15>A-35>A-16>Dowex HCR-W2. This was related to the size of average pore diameters and magnitude of BET surface area.

Esterification of Ethylene Glycol with Acetic Acid Catalyzed by Amberlyst 36

The reaction kinetics and the chemical equilibrium of the consecutive, reversible liquid-phase esterification of ethylene glycol with acetic acid to ethylene glycol monoacetate and ethylene glycol diacetate using the acidic ion-exchange resin Amberlyst 36 as catalyst were investigated. Kinetic experiments were accomplished for various temperatures and starting compositions of the reactants and products in the temperature range from 333.15 to 363.15 K. The experimental results of the heterogeneous catalyzed esterification and of the hydrolysis as backward reaction were used to derive a pseudohomogeneous model which is able to describe the reaction rate of the five-component system starting from any initial composition. Based on a pseudohomogeneous attempt, the applicability of mole fractions and activities for the description of the reaction rates as a function of time were compared.

Studies on the Stabilization of Modified Lyocell Solutions

AbstractAdditives with functional properties makes the Lyocell process a versatile tool for the creation of new innovative materials beyond the textile sector. Occupying functional groups or active surfaces the additives emphasize the suitability of Lyocell fibers, but simultaneously enhance the complexity of chemical reactions in cellulose/N‐methylmorpholine‐N‐oxide (NMMO) solutions, respectively. Concerning to the concentration acidic ion exchange resins, activated charcoals, carbon black etc. shift the start of decomposition to lower temperatures, decrease the viscosity, enhance the formation of amines as the main degradation products or cause autocatalytic reactions.New routes in stabilization of modified Lyocell solutions applying a polymeric stabilizer system are described. Using calorimetric, UV/VIS, ESR and HPLC analysis the degradation processes and thermal stability of modified Lyocell solutions compared to the unstabilized were studied. Moreover, as kinetic investigations show a distinguished behavior for modified solutions autocatalytic reactions can be suppressed by the stabilizing system. ESR kinetic study of radicals reveals that formation and recombination rates of radical reactions depend on cellulose concentration in Lyocell solutions and additional ingredients.

Physicochemical Characteristics of ZnS Immobilized on Spherical Activated Carbon for Removing HA(Humic Acid)

In this study, spherical activated carbons contained ZnS(Zn-SPAC) were successfully prepared through carbonization/activation processes. Strong acid ion exchange resin as starting material of Zn-SPAC was treated by 0.01 N zinc solution. Ion exchange treatment was performed from one time to three times for controling zinc content. The ion exchanged resins was activated under N2/H2O-vapor atmosphere at 900 °C for 0.5 hr following by carbonization treatment at 700 °C under N2 atmosphere. The Zn-SPAC samples were measured physicochemical characteristics such as X-ray patterns, SEM image, energy dispersive X-ray spectra, BET specific surface area, intensity and zinc content and used to remove humic acid(HA) in batch reactor for measuring photochemical activity. The X-ray patterns were appeared ZnS type. The Zn-SPAC had large BET specific surface area and their shape was spherical with a diameter about 350 ~ 400 μm. When the Zn-SPAC were dosed in UV reactor, the HA removal efficiency increased upto 60 % at 4hr. The order hand, the HA removal efficiency by only UV-C(λmax =254nm) irradiation was not good about 15 %. Therefore, we infer that the Zn-SPAC have good photochemical activity and presented possibility of photocatalyst for water purification.