Solid Resin Research Articles

Acidic resin-catalysed conversion of fructose into furan derivatives in low boiling point solvents

Conversion of fructose into furan derivatives 5-hydroxymethylfurfural (HMF) and 5-methoxymethylfurfural (MMF) is performed in tetrahydrofuran (THF) and methanol–organic solvent systems, catalysed by an acidic resin Amberlyst-15. The melted fructose can be converted into HMF on the surface of the solid resin catalyst in the presence of THF as an extracting phase, which is a good solvent for HMF and other by-products. The solid resin catalyst can be reused eleven times without losing its catalytic ability, with an average HMF yield of approximately 50%. Upon the addition of methanol, the generated HMF can further react with methanol to form MMF, and the total yield of HMF and MMF could be promoted to 65%. GC–MS analysis confirms the formation of a small amount of methyl levulinate in methanolorganic solvent system.

Noncorrosive ionic liquids composed of [HSO 4] as esterification catalysts

Seven Brønsted acidic ionic liquids (BAILs) composed of [HSO 4] were prepared, characterized, and used as catalysts of low dosage in various esterification reactions. Pyridinium hydrogensulfate ([Hpy][HSO 4]), 2-methylpyridine hydrogensulfate ([Hmpy][HSO 4]), and 1-methylimidazole hydrogensulfate ([Hmim][HSO 4]) are found to be nearly noncorrosive, whereas N-(4-sulfonic acid)butyl triethylammonium hydrogensulfate ([BSEt 3N][HSO 4]) corrodes 316L stainless steel heavily. It is illustrated that the acidity and hydrophilicity can be tuned through the variation in cations to obtain BAILs of suitable catalytic activity. [Hpy][HSO 4], as a typical noncorrosive BAIL, shows good catalytic activity in the esterification of n-butanol with acetic acid, primarily due to its suitable Brønsted acidity and highly hydrophilic nature to enable liquid–liquid biphasic catalysis, whereas [Hmpy][HSO 4] and [Hmim][HSO 4] require relatively large dosages to reach the equal level. The batch reaction distillation is further performed to investigate the esterification of acetic acid with n-butanol using [Hpy][HSO 4] as catalyst of low dosage, and is found to be a promising strategy that causes the shift of chemical equilibrium further to the product side and leads up to the completion of the reaction. The noncorrosive BAILs are also tested to be catalysts of considerable activity for the esterification of other alcohols with acids in the absence of steric hindrance. [Hpy][HSO 4] is recycled and reused seven times without significant losses of activity and quantity, showing the stability and recyclability of the noncorrosive BAILs. It is believed that the noncorrosive BAILs are prospective substitutes for corrosive mineral acids or solid resins in the catalytic distillation to overcome the corrosion of mineral acids or the difficult installation of solid catalysts in the column.

Separation of fructose and glucose from date syrup using resin chromatographic method: Experimental data and mathematical modeling

In this work a series of experiments have been performed to study and simulate the separation of glucose and fructose as the most applicable sugars in the food industry. The objective of this work is understanding and modeling the behavior of these components in a chromatography column when they are introduced to the column as simple components, binary solutions, and also as the major species in date syrup. The column's diameter and height are 3.5 cm and 15 cm respectively, and Purolite PCR642Ca, which is an acidic gel-type cation exchange resin (Ca 2+), was used for the separation of sugars. Static method was applied to determine the equilibrium constants, and frontal (dynamic) analysis method was used to determine the mass transfer coefficients at two different temperatures of 30 and 60 °C for single and multi-component mixtures for a solution with a sugar concentration of 70 g/L. The kinetic studies for the prediction of mass transfer coefficients were performed according to the breakthrough curves by a linear driving force approximation (LDF), while the adsorption isotherms were estimated by linear model. Adsorption equilibrium constants and mass transfer coefficients between fructose, glucose and solid resin were determine by optimization procedure. The results of the optimization and parameter estimation for synthetic sugar solutions were also applied for modeling the separation of sugars in date syrup. The predicted results of the real mixtures (date syrup) have a good agreement with the experimental data and show that both sugars can be separated successfully by this method.

Nonisothermal curing of a solid resole phenolic resin

AbstractA commercial solid resole phenolic resin was thoroughly characterized with Fourier transform infrared spectroscopy, NMR, and gel permeation chromatography, and its nonisothermal curing reaction was studied systematically with differential scanning calorimetry at a series of heating rates (βs) of 3, 4.5, 5.7, and 10°C/min. The results show that the solid resole had a higher molecular weight than conventional liquid resoles, and its reactive hydroxymethyl (CH2OH) and dibenzyl ether (CH2OCH2) functionalities participated in the crosslinking reaction upon heating. The nonisothermal curing reaction of the solid resole exhibited a relatively constant reaction heat, whereas the onset, peak, and end curing temperatures increased gradually with increasing βs. In addition, the reaction kinetics of the solid resole was analyzed with an nth‐order reaction model, the global activation energy was determined with the Kissinger method, and the reaction order was derived from the Crane equation. The obtained rate equation was applied to simulate the reaction time, conversion, and reaction rate, with a good fit achieved between the experimental data and the model predications. In conclusion, this study provided us with new knowledge on solid resoles at a molecular level and was also a great help for the curing procedure design, property optimization, and practical application of this commercial solid resole. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Ceramic foams and micro-beads from emulsions of a preceramic polymer

A commercially available solid silicone resin was dissolved in a solvent and emulsified via stirring in the presence of water and surfactant to form three different types of emulsions, namely water-in-oil (w/o), water-in-oil-in-water (w/o/w) and oil-in-water (o/w), by following different preparation procedures. After curing, thermosets possessing different morphologies, ranging from highly porous (monolithic) foams to porous micro-beads and solid micro-beads, formed. The samples kept their shape upon pyrolysis, and resulted in ceramic foams (via w/o) and porous micron sized (∼200 μm) spherical particles (via w/o/w) having more than 80 vol% of total porosity, while with o/w emulsification solid SiOC ceramic particles with an average diameter of ∼100 μm formed. Both surfactant and water altered the IR spectra for emulsion-derived thermoset samples, in comparison to the pure cured resin, but upon pyrolysis similar amorphous ceramics were obtained from all samples.

Alternative Plugs Flow Liquid Chromatography (APFLC)/EI-MS System Using a T-shaped Flow Path

The vapor condensation method can be used for forming an alternative flow of liquid masses using a single solvent for alternative plugs flow liquid chromatography (APFLC), described in our previous paper. APFLC is more effective when adopting a T-shaped flow path and aqueous-organic solvents with a liquid-to-gas volume ratio (bulk fraction; β) ranging between 0.0006 and 0.004 in an open tubular GC capillary column at below 70°C. High-density plugs flow by a T-shaped flow path leads to extremely high resolution. Alternative plugs flow is formed when the liquid contact angle to the solid phase is above 75°. An aqueous mixture of the usual HPLC solvent can be readily used for APFLC. An EI-mass spectrum is obtained that is comparable with that in the NIST library, except for the DMF mixture medium. Due to low-pressure loss properties in the column, the system does not require a high-pressure liquid pump. Solid hydrocarbon resin with a contact angle to water of between 75° and 79°, such as polystyrene and olefinic polymers, is anticipated to be applicable to APFLC and hydro-membrane gas chromatography (HMGC) by a consideration of their surface tensions.

Cu-Catalyzed Carbon-Heteroatom Coupling Reactions under Mild Conditions Promoted by Resin-Bound Organic Ionic Bases

Resin-bound organic ionic bases (RBOIBs) were developed in which tetraalkyl-ammonium or phosphonium cations are covalently attached to solid resins. The application tests showed that the performance of the tetraalkyl-ammonium-type RBOIBs is slightly better than that of the corresponding Cs salts in Cu-catalyzed C-N cross-couplings, while the tetraalkylphosphonium-type RBOIBs are significantly better than all the inorganic bases. With these newly developed RBOIBs, room-temperature Cu-catalyzed C-N coupling with various nonactivated aryl iodides and even aryl bromides can be readily accomplished. Moreover, RBOIBs can be easily recycled and reused for a number of times without much drop of activity. The good performances of RBOIBs are proposed to arise from the relatively weak binding forces between the cationic polymer backbone and basic anions, as opposed to the strong metal-anion interactions in the inorganic bases. Further applications of RBOIBs in Ni-catalyzed Suzuki-type couplings at room temperature, Cu-catalyzed C-N couplings at -30 °C, a Pd-catalyzed Heck reaction at 60 °C, and Cu-catalyzed C-S couplings at room temperature demonstrate that RBOIBs are generally applicable bases with improved performance for many other types of organic transformations.

Synthesis, characterization, and star polymer assembly of boronic acid end‐functionalized polycaprolactone

AbstractBoronic acid end‐functionalized polycaprolactone (PCL) polymers were synthesized by ring‐opening polymerization using a pinacol boronate ester‐containing (Bpin) initiator. The polymerization provides access to boron‐terminated polymers (i.e. Bpin‐PCL‐OH) with narrow molecular weight distributions (PDI = 1.09). Postsynthetic manipulation of the polymer's terminal hydroxyl group by copper‐catalyzed azide‐alkyne cycloaddition chemistry provides a series of bis end‐functionalized polymers with significant structural diversity at the termini. Deprotection of the boronate ester end group was accomplished with an acidic solid phase DOWEX resin. The boronate ester deprotection methodology does not result in hydrolysis of the polymeric backbone. The boronic acid‐tipped polymers were converted into star polymer assemblies using thermal dehydration and ligand‐facilitated trimerization. Thermal dehydration of (HO)2B‐PCL‐OAc to the corresponding boroxine‐based star polymer assembly was inefficient and lead to degradation products. Ligand‐facilitated trimerization using either pyridine or 7‐azaindole as the Lewis base was efficient and mild. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010

Hydrodynamic study on radially cross-flow fluidized bed multi-staged ion-exchange column

A hydrodynamic study was carried out on our patented radially cross-flow fluidized bed staged column, with the salt laden water and solid resins flowing counter-currently, to determine the loading/flooding criterion for a stable operation of the column, and also to ascertain the mal-distribution in flow. Residense time distribution measurements were taken to address the latter part of the study. The data collected from the hydrodynamic measurements show a wider range of liquid and solid flowrates that can be used for the stable operation of the column, in comparison to that obtained in the conventional multi-staged column. The extent of mal-distribution or channeling is also relatively smaller in the former. The observations are consistent with the mass-transfer results obtained in our recent study, where the separation of dissolved solids using the radially cross-flow ion exchange column was found to be 40% larger than that in the conventional column.

The Effect of Phenol Resin Types and Mixing Ratios on the Synthesis of High-Purity β-SiC Powder by the Sol-Gel Method

In this study, we carried out a sol-gel processing to synthesize two types of phenol resin and TEOS sol with fluoric acid as the catalysts, and fabricated the β-SiC powder by carbothermal reduction of the obtained precursor gels. The gels were observed to be cross linked between TEOS and phenol resins by FT-IR and TG-DTA. After pyrolyzed at 1000oC in Ar to obtain the precursor, to confirm the phase transition and morphologies by XRD, and SEM were measured. Finally, the light green colored SiC powder was obtained after carbothermal reduction process up to 1800oC. The residual condensed SiO(v) phase and free carbons as a role of impurities for final products using the solid type phenol resin was observed in the surface of powder by BSE.

Development of an Efficient Procedure for Determination of Copper, Zinc and Iron after Solid Phase Extraction on 3‐(1‐(1‐H‐Indol‐3‐yl)‐3‐Phenylallyl)‐1H‐Indole Loaded on Duolite XAD 761

AbstractA method for the simultaneous preconcentration of Cu2+,Zn2+ and Fe3+ ions, in some food samples has been reported. The method is based on the adsorption of 3‐(1‐(1‐H‐indol‐3‐yl)‐3‐phenylallyl)‐1H‐indole (IPAI) loaded on Duolite XAD 761. The metal ions adsorbed on the modified solid phase resin are eluted using 6 mL of 4 mol L−1 nitric acid. The influences of the analytical parameters including pH and amount of ligand and solid phase and type and amount of surfactant and sample volume on the metal ions recoveries were investigated. The effects of matrix ions on the retentions of the analytes were also examined. The recoveries of analytes were generally higher than 95% with a RSD lower than 5%. The method has been successfully applied for these metals content evaluation in some real samples.

Practical Approaches for Taste Masking of Bitter Drug: A Review

Taste is most important organoleptic aspects about the acceptance of oral drugs. Bitter and unpalatable taste is a major problem of certain drugs in formulations. In market, there are numbers of pharmaceutical preparations available in which actives are bitter in taste. The improved palatability in these products has prompted the development of numerous formulations, which improved performance and acceptability. The bitterness of preparation also leads to patient incompliance. So masking of bitterness becomes essential and done by masking the bitter taste of drugs by either decreasing its oral solubility on ingestion or decreasing the amount of drug particles exposed to taste buds thereby reducing the perception of bitter taste. Methods commonly used for taste masking involves various physical and chemical method that prevent the interaction of taste bud with drugs and are based on coatings, solid dispersion system and ion exchange resin, entrapment method and masking of taste buds etc. Taste masking of bitter drugs become necessity in case of oral administration and selection of technology depends upon the bitterness of drugs and their compatibility with taste masking agents that does not affect the bioavailability of drug

Layer-by-Layer Deposition of Silver/Gold Nanoparticles for Catalytic Reduction of Nitroaromatics

A general method has been fabricated to achieve normal as well as inverted core-shell architectures of silver/gold through a layer-by-layer deposition technique on a commercial anion exchange resin. Electrostatic field force of the charged resin beads supports immobilization of anionic metal precursors [MX(n)]-, in turn deposition of silver/gold nanoparticles onto the solid resin matrix and reduction of 2-nitrobenzoic acid to obtain the corresponding amines through effective catalysis. The shell thickness has been tailored made by exploiting a new method of cyclic and repetitive deposition of the desired metal precursors. Thermodynamic parameters for the reduction reaction have been presented. Kinetic study reveals a comparative account of rates between the mono- and bi-metallic nanoparticles where silver stands to be a better catalyst for the reduction of nitroaromatics.

Facile one-pot synthesis and characterization of maleated hydrocarbon resin tackifier for improved adhesion

This work reports for the first time the facile method for grafting maleic anhydride (MAH) to solid C5-aliphatic hydrocarbon resin tackifier (HCR). MAH grafting has been carried out thermally (240°C) without using any peroxide. It has been shown that up to 30 wt% of MAH can be conveniently grafted to the HCR via thermal process. Fourier transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance ( 1H-NMR) spectroscopy confirm that the MAH has been appended to the HCR. The effect of varying MAH concentration, reaction time and reaction temperature on the grafting efficiency (GE) has been reported. The grafting degree (wt%) and grafting efficiency (GE) of the maleated (MA-g-HCR) samples have been determined by FT-IR spectroscopy and solvent extraction. The MA-g-HCR samples have been thoroughly characterized by using gel permeation chromatography, differential scanning calorimetry, thermogravimetric analysis, contact angle measurements and X-ray photoelectron spectroscopy. A steady increase in the molecular weight, glass transition temperature, melting point and maximum degradation temperature of the HCR tackifier has been observed with the increasing weight percentage of MAH grafting. It has been shown that the polar component of the surface energy of HCR resin can be increased up to 9±3 mN m −1 by grafting 30 wt% of MAH.

Development and Characterization of Novel Fore Safe Epoxy Resins

The curing system for newly developed solid state fire safe epoxy resins using dicyandiamide (DICY) was introduced. Composites of epoxy resins obtained from diglycidyl ether of 1,1-dichloro-2,2bis(4-hydroxyphenyl)ethylene bisphenol-C (BPC) and bisphenol-A (BPA) epoxy resins in the reaction with BPC and BPA and DICY hardener were studied. Solid epoxy resins were synthesised by the use of two different heating methods: conventional and microwave reactor. The quantities of DICY additions were 0.5–5.0 %, optimum was found to be 3 %. Limited oxygen index (OI) tests for different epoxy resins and addition of flame – retardants were carried out. The highest value of OI was 34.6. As additional flame-retardants were used zinc stannates (ZS, ZHS). Evident OI increase was noted from 27.0 for classical epoxies, 34.6 for BPC cured epoxies and 44 for cured composites with the addition of Zn/Sn flame-retardants.

Low Temperature De-acidification Process of Animal Fat as a Pre-Step to Biodiesel Production

An esterification process is proposed to lower Free Fatty Acids (FFA) content in waste animal fat using solid acid ion exchange resins as catalysts. The final aim is to make this material a suitable feedstock for biodiesel production. Its exploitation does not interfere with the food chain, besides allowing to lower biodiesel production costs.

Biodiesel production from acid oils and ethanol using a solid basic resin as catalyst

In the search of an alternative fuel to substitute diesel fuel, biodiesel appears as one of the most promising sources of energy for diesel engines because of its environmental advantages and also due to the evolution of the petroleum market. Refined oil is the conventional raw material for the production of this biofuel; however, its major disadvantage is the high cost of its production. Therefore, frying oils, waste oils, crude oils and/or acid oils are being tested as alternative raw materials; nevertheless, there will be some problems if a homogeneous basic catalyst (NaOH) is employed due to the high amount of free fatty acid present in the raw oil. In this work, the transesterification reaction of acid oil using solid resin, Dowex monosphere 550 A, was studied as an alternative process. Ethanol was employed to have a natural and sustainable final product. The reaction temperature's effects, the initial amount of free fatty acid, the molar ratio of alcohol/oil and the type of catalyst (homogeneous or heterogeneous) over the main reaction are analyzed and their effects compared. The results obtained show that the solid resin is an alternative catalyst to be used to produce fatty acid ethyl esters (FAEEs) by a transesterification reaction with a final conversion over 90%. On the other hand, the time required to achieve this conversion is bigger than the one required using conventional technology which employs a homogeneous basic catalyst. This reaction time needs to be optimized.

Hierarchical Superparamagnetic Magnetite Nanowafers from a Resin-Bound [Fe(bpy)3]2+ Matrix

The brilliant red [Fe(bpy)(3)](2+) complex upon immobilization on a strongly acidic cation exchanger or in situ formation of the same cationic complex onto a resin matrix and subsequent modified hydrothermolysis (MHT) at approximately 110 degrees C produces unusually stable hierarchical magnetite (Fe(3)O(4)) nanowafers. The slow hydrothermolysis, oxidation, and subsequent dehydration of the complex on the solid-liquid interface produce stable hierarchical nanostructures. The isolation of neat Fe(3)O(4) (uncapped) particles from the resin matrix as hierarchical nanowafers was achieved by magnetically stirring a CH(3)CN suspension of nanocomposites. The solid resin support not only aids nanowafer formation on its surface but also provides unique stability to the magnetite particles, where nanowafer oxidation is largely retarded. The utility of the as-prepared porous nanocomposite and characterization of the nanoparticles are promising for nanotechnological and soft ferromagnetic applications.

Characterization and application of SuperLig® 620 solid phase extraction resin for automated process monitoring of 90Sr

Characterization of SuperLig® 620 solid phase extraction resin was performed in order to develop an automated on-line process monitor for 90Sr. The main focus was on strontium separation from barium, with the goal of developing an automated separation process for 90Sr in high-level wastes. High-level waste contains significant 137Cs activity, of which 137mBa is of great concern as an interference to the quantification of strontium. In addition barium, yttrium and plutonium were studied as potential interferences to strontium uptake and detection. A number of complexants were studied in a series of batch Kd experiments, as SuperLig® 620 was not previously known to elute strontium in typical mineral acids. The optimal separation was found using a 2 M nitric acid load solution with a strontium elution step of ~0.49 M ammonium citrate and a barium elution step of ~1.8 M ammonium citrate. 90Sr quantification of Hanford high-level tank waste was performed on a sequential injection analysis microfluidics system coupled to a flow-cell detector. The results of the on-line procedure are compared to standard radiochemical techniques in this paper.

Dimethyl secondary amine chain extenders: a conceptual approach to in situ generation of advanced epoxy resins for rapid cure, low VOC coatings

Solid epoxy resin oligomers have traditionally been utilized for coatings that combine fast dry-to-touch speed and good flexibility, properties greatly in demand in many applications such as marine and industrial maintenance coatings. Unfortunately, solid epoxy resins require formulation with large quantities of solvent that make the attainment of modern VOC regulations difficult or impossible. Coatings formulated from low molecular weight liquid epoxy resin (LER) on the other hand, can more easily meet VOC challenges, but dry slowly and tend to be brittle. This article explores the concept of using fast reacting, difunctional amine chain extenders to generate epoxy oligomers in situ as a means of meeting these opposing property demands. Methylamine-terminated poly(N-methylazetidine) (p-NMAz) is prepared in a two-step process involving the Michael addition of methylamine to acrylonitrile followed by hydrogenation in a methylamine-containing atmosphere to yield an oligomer stream with an Mn of about 250. Hydrogenation of isophthalonitrile in a methylamine-containing atmosphere yields N,N′-dimethyl-meta-xylylenediamine (DMMXDA). Competitive pseudo-first-order kinetic measurements conducted in isopropyl alcohol indicate these amines react approximately 3–3.6 times faster with phenyl glycidyl ether (PGE) than the primary amine meta-xylylenediamine (MXDA). These chain extenders can be formulated with traditional multifunctional amine crosslinkers to yield coatings with lower VOC, faster dry speed, and better flexibility compared with corresponding coatings formulated without the chain extender. Consistent with their chemical structures, p-NMAz proved capable of yielding coatings with the best impact resistance and mandrel bend properties, while DMMXDA yielded coatings with better water and corrosion resistance properties. Open image in new window