Sulfonic Acid Resin Research Articles

ChemInform Abstract: Organic Reactions Catalyzed by Solid Superacids. Part 9. Friedel- Crafts Cyclobenzylation of Benzene with Bis(hydroxymethyl) diarylalkanes Catalyzed by a Perfluorinated Sulfonic Acid Resin ( Nafion-H).

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform Abstract: Organic Reactions Catalyzed by Solid Superacids. Part 10. Perfluorinated Sulfonic Acid Resin (Nafion-H) Catalyzed Ring Closure Reaction of 2,2′-Diaminobiphenyls. A Preparative Route to Carbazoles.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform Abstract: High Catalytic Activity of an Insoluble Acidic Caesium Salt of Dodecatungstophosphoric Acid for Liquid-Phase Alkylation.

The use of solid acid catalysts is often desirable for liquid-phase reactions [1] in the place of homogeneous catalysts such as H2SO4 [2] and HA12CI: [2,3]. Among the various solid acids that were tested for liquid-phase alkylation of aromatic hydrocarbons [4-8], perfluorinated resinsulfonic acid (Nation-H) has been reported as being a good catalyst [4,5]. The authors have previously found that solid heteropoly compounds, H3PW1204o and their acidic caesium salt, where highly active catalysts for the dehydration of alcohols in the gas phase [9-12] and for the decomposition of ester in the liquid phase [ 13 ]. Here we wish to report on the high activities of Ho.sCs2.~PW12040 for the alkylation of aromatic compounds with cyclohexene. This catalyst was found to be much more active than HY, H-ZSM-5, and Nafion-H. Ho..~Cs2.sPW1204o (abbreviated as Cs2.5-salt) was obtained as a precipitate by the titration of an aqueous solution of H3PWI2QO (Nippon Inorganic Colour and Chemicals) with an aqueous solution of Cs2CO3 as described before [9-13 ]. Carbon-supported H3PW~204o [14] was prepared with an activated carbon (Wako Pure Chemicals) and an aqueous solution of H3PW~204o. The amount of H3PWI204o loaded was 18 wt.-%. This is denoted by H3PW~204o/ AC. SiO2-A12Os (SA-1, Catalysts and Chemicals Industries; A1203 : 13 wt.-% ), Nafion-H (NR-50, Mitsui Toatsu Fine Chemicals), H-ZSM-5 (25H, Mobil Catalysts Company of Japan), HY-zeolite (prepared from SK-40, Linde), aluminium exchanged montmorillonite (prepared from Kunipia-F, Kunimine Kogyo), H2SO4-treated ZrO~ (abbreviated as SO42-/ZrO2) [15,16], and HA12C17 [3] were used as reference catalysts.

Microwave-Assisted Nafion-H Catalyzed Friedel–Crafts Type Reaction of Aromatic Aldehydes with Arenes: Synthesis of Triarylmethanes

A new solid acid Nafion-H, a perfluorinated sulfonic acid resin, catalyzed microwave-assisted synthesis of triarylmethanes is described. Various benzaldehydes react readily with arenes to provide the corresponding triarylmethanes in good to excellent yields. The reactions were carried out under solvent free conditions under microwave irradiation in a pressure vessel. The solvent free microwave irradiation methods appears to be an environmentally friendly synthetic protocol providing products in significantly shorter reaction times over traditional heating methods carried out in a pressure tube.

Di-d-fructose Dianhydride-Enriched Products by Acid Ion-Exchange Resin-Promoted Caramelization of d-Fructose: Chemical Analyses

Caramelization commonly occurs when sugars, or products containing a high proportion of sugars, are heated either dry or in concentrated aqueous solutions, alone or in the presence of certain additives. Upon thermal treatment of sugars, dehydration and self-condensation reactions occur, giving rise to volatiles (principally 2-hydroxymethylfurfural, HMF), pigments (melanoidines) and oligosaccharidic material, among which di-D-fructose dianhydrides (DFAs) and glycosylated DFA derivatives of different degree of polymerization (DP) have been identified. This study reports a methodology to produce caramel-like products with a high content of DFAs and oligosaccharides thereof from commercial D-fructose based on the use of acid ion-exchange resins as caramelization promotors. The rate of formation of these compounds as a function of D-fructose concentration, catalyst proportion, temperature, catalyst nature and particle size has been investigated. The use of sulfonic acid resins allows conducting caramelization at remarkable low temperatures (70-90 degrees C) to reach conversions into DFA derivatives up to 70-80% in 1-2 h, with relative proportions of HMF < 2%.The relative abundance of individual DFA structures can be modulated by acting on the catalyst nature and reaction conditions, which offers a unique opportunity for nutritional studies of DFA-enriched products with well-defined compositions.

Biodiesel production from crude palm oil using sulfonic acid-modified mesostructured catalysts

Biodiesel production from crude palm oil containing high percentage of free fatty acids over sulfonic acid-functionalized SBA-15 materials (propyl-SO 3H, arene-SO 3H, perfluoro-SO 3H) has been studied. The catalytic results showed that sulfonic acid-modified mesostructured materials were more active than conventional ion-exchange sulfonic resins (Amberlyst-36 and SAC-13) in the simultaneous esterification of free fatty acids and transesterification of triglycerides with methanol. The reusability of the catalysts was also investigated showing high stability for propyl-SO 3H and arene-SO 3H-modified mesostructured materials. In contrast, ionic-exchange sulfonic acid resins displayed low-conversion rates, being stronger this decay of activity in the second consecutive catalytic run. Interestingly, perfluorosulfonic acid-functionalized SBA-15 sample yielded a dramatic loss of activity indicating that Si–O–C bonding is not stable under the reaction conditions as compared with Si–C bond present in propyl-SO 3H and arene-SO 3H catalysts. Further functionalization of arene-SO 3H SBA-15 catalyst with hydrophobic trimethylsilyl groups enhanced its catalytic performance. This material was able to produce a yield to FAME of ca. 95% as determined by 1H NMR in 4 h of reaction with a moderate methanol to oil molar ratio (20:1), 140 °C and a catalyst concentration of 6 wt.% referred to starting oil.

Synthesis of theThieno[3,2-b]thiophene and Thieno[3,2-b]furan Bare Ring Systems

Reported here is an optimized synthesis of thieno[3,2-b]thiophene as well as the first synthetic route to thieno[3,2-b]furan. The Li-Br exchange of 3-bromothiophene with t-BuLi followed by quenching with 1,2-bis(2,2-diethoxy­ethyl)disulfide afforded 1 in 94% yield. Then, treatment of 1 with a sulfonic acid resin gave the thieno[3,2-b]thiophene 2 in 71% yield. After optimization of the conditions utilizing the same method in THF thieno[3,2-b]furan 4 was synthesized from 3 in 32% yield.

Sulfonated polystyrene: A catalyst with acid and superabsorbent properties for the esterification of fatty acids

In this work, catalysts with acid and superabsorbent properties were obtained by sulfonation of expanded polystyrene and used to promote the esterification of oleic acid with ethanol. The prepared superabsorbent polymers (SAP) showed high concentration of active sulfonic acid sites (0.7–5.9 mmol acid sites g −1) and high water absorption capacity (445–900 g water g −1). It was observed that the catalytic activity increased with the number of acid site and water absorption capacity. Turnover frequencies suggested that the catalytic activity depends on the accessibility/diffusion processes determined by the crosslinks in the polymer. Commercial sulfonic acid resins and polyacrylate based superabsorbent polymers showed very low activities compared with the SAP produced. The SAP also showed higher activity compared to the homogeneous catalyst p-toluenesulfonic acid. The higher activity of the prepared SAP is discussed in terms of the acidity of sulfonic groups combined with the water absorption which shifts the esterification equilibrium.

Kinetics of free fatty acids esterification: Batch and loop reactor modeling

Biodiesel is a fuel derived from a renewable vegetable origin and is object of growing interest in recent years both as a pure fuel and as blending component to reduce exhaust pollutants of traditional diesel fuel. The conventional biodiesel production technology involves the use of alkaline catalysts and is therefore not compatible with large amounts of free fatty acids (FFAs) and moisture in the feedstock due to the formation of soaps that strongly affect the feasibility of glycerol separation by liquid–liquid splitting. A preliminary stage of acidity reduction is therefore necessary, for this process, if the starting material is characterized by a free acidity higher than 0.5% by weight often contained in cheaper feedstock which lowers the production costs. This can be pursued, for example, by means of an esterification reaction of the FFAs with methanol, catalyzed by ionic-exchange sulphonic acid resins. In the present work, the above-mentioned reaction has been studied in different reactor configurations on a model mixture composed by artificially acidified soybean oil with oleic acid using an acid exchange resin as catalyst. This work has been developed in two parts: (i) a kinetic study in batch conditions with the purpose of developing a suitable kinetic expression and determining the related parameters and (ii) a study of the FFAs esterification in a packed bed tubular reactor operated inside a circulation loop. The kinetic model that is developed on the basis of several batch runs is able to simulate also the behavior of dynamic tubular loop reactor, providing that the external mass transfer resistance is properly accounted for. The mass transfer coefficient is satisfactorily modeled using correlations available on literature.

Environmentally Benign Contemporary Friedel-Crafts Chemistry by Solid Acids

Recent advances in the development of environmentally benign solid acid-catalyzed Friedel-Crafts reactions are reviewed. The work includes two main chapters, alkylations and acylations. The data are summarized based on the chemical nature of the reagents used, such as alkenes, alkyl halides and alcohols/ethers in alkylation, while activated carboxylic acid derivatives and carboxylic acids in acylation. Special topics in both major chapters, such as hydroxyalkylation, cyclialkylation, cycliacylation and rearrangements are also discussed. Keywords: Friedel-Crafts, alkylation, acylation, solid acid, zeolite, montmorillonite, sulfonic acid resin, heteropolyacid

New Two-Step Process for Propene Oxide Production (HPPO) Based on the Direct Synthesis of Hydrogen Peroxide

In previous papers, we showed that (i) neutral solutions of hydrogen peroxide can be safely obtained by the direct reaction of H2 and O2 gas mixtures in the presence of Pd-loaded sulfonic acid resins and (ii) low molecular weight olefins can be successfully epoxidized using aqueous solutions of H2O2 in the presence of amorphous Ti/SiO2 catalysts. Against this background, this paper seeks to go one step further in our on-site H2O2 strategy by combining the direct synthesis of nonacidic H2O2 solutions with the catalyzed epoxidation of alkenes with hydrogen peroxide. In a first step, we optimized the reaction conditions for the direct synthesis of H2O2 working in a semibatch reactor. Aqueous solutions of 9 wt % H2O2 were then used in the epoxidation of oct-1-ene on a Ti-loaded amorphous silica catalyst, and reaction conditions were optimized. Finally, the propene epoxidation reaction was conducted in a continuous mode under the optimum reaction conditions selected (343 K, H2O2/catalyst ratio = 1:4, propene/c...

Acid-catalyzed etherification of bio-glycerol and isobutylene over sulfonic mesostructured silicas

Sulfonic acid-modified mesostructured silicas have demonstrated an excellent catalytic performance in the etherification of glycerol with isobutylene. Their activity and selectivity towards valuable products for fuel bio-additives (di- tert -butylglycerols and tri- tert -butylglycerol) have shown to be comparable or even superior to those of macroporous commercial sulfonic acid resins. Sulfonic-acid-functionalized mesostructured silicas have demonstrated an excellent catalytic behavior in the etherification of glycerol with isobutylene to yield tert -butylated derivates. Di- tert -butylglycerols (DTBG) and tri- tert -butylglycerol (TTBG) have shown to be valuable fuel additives leading to decreases in the emission of particulate matter, hydrocarbons, carbon monoxide and unregulated aldehydes. Likewise, said ethers can also act as cold flow improvers for use in biodiesel, reducing also its viscosity. The activities and selectivities achieved over sulfonic acid-functionalized mesostructured silicas are comparable or even superior to those displayed by widely used macroporous commercial acid resins. Under optimized reaction conditions, these mesostructured catalysts yield a complete glycerol conversion with a combined selectivity towards DTBG and TTBG up to ca. 90%. Furthermore, no formation of undesirable isobutylene oligomers is observed. The acid strength of the sulfonic acid sites has also been found to be an important factor affecting the catalytic performance of these materials.

Beckmann rearrangement of cyclohexanone oxime to ε-caprolactam catalyzed by sulfonic acid resin in DMSO

Abstract The catalytic liquid-phase Beckmann rearrangement of cyclohexanone oxime to e -caprolactam over solid sulfonic acid resin in dimethyl sulfoxide (DMSO) has been successfully performed. The influences of solvent, catalyst, reaction temperature and reaction time on the rearrangement of cyclohexanone oxime in the liquid-phase were examined. The results indicate that conversion of oxime can reach 100% with 97.9% of selectivity to e -caprolactam under optimal reaction conditions. This catalytic system involved is environmentally harmless, easily separate, and the catalyst can be conveniently recovered for recycled use.

Mesoporous organosilicas containing disulfide moiety: Synthesis and generation of sulfonic acid functionality through chemical transformation in the pore wall

Mesoporous organosilicas with disulfide moiety bridged in the pore wall have been synthesized by co-condensation of bis[3-(triethoxysilyl)propyl]disulfide (BTPDS) and tetramethoxysilane (TMOS) in acetic acid/sodium acetate buffer solution (HAc–NaAc, pH 4.4), using nonionic surfactant P123 as the template. With the molar percent of BTPDS increasing, the mesostructure of the resultant material transforms from highly ordered 2-D hexagonal structure to cellular foam structure. The disulfide moiety could be transferred to sulfonic acid functionality by a simple post-oxidation method. The structural characterizations show that the mesostructure changes during the oxidation step especially for the materials with high content of disulfide moiety. In the esterification of aliphatic acid and ethanol, the oxidized materials show higher yield than the conventional heterogeneous solid acids such as zeolites and sulfonic acid resin. Comparisons of the structural properties and the catalytic results of the materials show that a large pore diameter and low surface hydrophilicity are required to obtain high catalytic activity.

Perfluorinated Sulfonic acid Resin (Nafion-H) catalysed Ritter reaction of Benzyl Alcohols

Perfluorinated sulfonic acid resin (Nafion-H) catalyst found to be effective in promoting the Ritter reaction of benzyl alcohols with nitriles such as acetonitrile, acrylonitrile and benzonitrile to give the corresponding N-benzylamides.

New polystyrene sulfonic acid resin catalysts with enhanced acidic and catalytic properties

The effects of halogenation of polystyrene sulfonic acid resins on acidic and catalytic properties have been evaluated. Four polystyrene- co-divinylbenzene sulfonic acid resins from Rohm and Haas (Amberlyst 70, Amberlyst 15, Amberlyst 35 and Amberlyst 36) have been characterised in terms of their acidities (both strength and acid site concentrations) by ammonia adsorption flow microcalorimetry, their thermal and hydrothermal stabilities, and their catalytic activities in two test reactions, the isomerisation of α-pinene and the benzylation of toluene using benzyl alcohol. Amberlysts 35 and 36 are “over-sulfonated” and exhibit stronger acid sites than the conventional sulfonated resin Amberlyst 15. These acid properties explain differences in catalytic activities, although differences between the porosities of Amberlysts 35 and 36 have a profound affect on catalytic performance in non-polar reaction media. Amberlyst 70, which is reported to be halogenated and is claimed to exhibit better thermal stability than the other three resins, shows acid site strengths similar to those of the over-sulfonated Amberlysts 35 and 36, and shows significantly better thermal and hydrothermal stability. It exhibits a relatively low pore volume, however, constraining its catalytic activity in non-swelling solvents.

Perfluorinated resin-sulfonic acid (Nafion-H): an efficient, environment friendly and recyclable heterogeneous catalyst for the one-pot multicomponent synthesis of β-acetamido ketones

Multi component condensation of an aryl aldehyde, acetyl chloride, acetonitrile and enolisable ketone in presence of Nafion-H, as an efficient, environment friendly heterogenous and recyclable catalyst for the one-pot synthesis of β-acetamido ketones in high yields is described.

Kinetics and Mass Transfer of Free Fatty Acids Esterification with Methanol in a Tubular Packed Bed Reactor: A Key Pretreatment in Biodiesel Production

Biodiesel can be easily obtained starting from high-quality or refined vegetable oils and performing on these feedstocks a transesterification reaction usually promoted by alkaline catalysts in the homogeneous phase. In this production scheme the employment of low-quality or waste raw materials, as cheap as possible, must be carefully considered to strongly improve the economic competitiveness of this biofuel with respect to the petroleum-derived diesel. In the case of raw materials characterized by a high content of free fatty acids (FFAs), a preliminary esterification treatment with methanol or ethanol is necessary for the abatement of the FFA concentration below the threshold limit value of 0.5−1.0% by weight that is tolerable by the subsequent process step of alkaline transesterification. In the present work the esterification reaction in tubular packed bed reactors, operating under pressure and using a sulfonic acid resin as catalyst, has been extensively studied. As it is well-known, sulfonic exchan...

Fischer−Tropsch Aqueous Phase Refining by Catalytic Alcohol Dehydration

Polar products from Fischer−Tropsch synthesis, such as short-chain alcohols, carbonyl compounds, and carboxylic acids, on condensation, dissolve in the water formed in the Fischer−Tropsch process to form an aqueous product phase. Recovery of the organic compounds from this aqueous product phase involves complex separations, and catalytic dehydration of alcohols to olefins was investigated as a means to simplify the separations. Dehydration of alcohol mixtures (some containing water) was investigated to determine whether C2−C8 alcohols can be coprocessed and whether branched alcohols can be selectively dehydrated in the presence of linear alcohols. In the presence of an η-alumina catalyst, the ease of alcohol dehydration increased with increasing carbon number, and mixtures could be dehydrated completely with >95% selectivity to olefins. The molar ratio of secondary and tertiary alcohol dehydration to primary alcohol dehydration obtained with a sulfonic acid resin catalyst (Amberlyst 15) at 100−115 °C was ...

Comparison of Different Reactor Configurations for the Reduction of Free Acidity in Raw Materials for Biodiesel Production

Waste oils used in biodiesel production contain high concentrations of free fatty acids. We studied the esterification of oleic acid, dissolved in soybean oil, with methanol in order to simulate its behavior. We used sulfonic exchange acid resin as the catalyst in two different reactors: a well-stirred slurry reactor (WSSR) and a spray tower loop reactor (STLR) both working at atmospheric pressure. Methanol was fed continuously to both the reactors with very low feed rates in order to minimize the amount of methanol emerging from the reactor outlet. This methanol removed the water produced in the reaction thereby favoring esterification. The WSSR and STLR had very similar performance in that were both better than that of a plug flow reactor (PFR) working in the same conditions of atmospheric pressure and low methanol feed rate. Both the WSSR and STLR showed liquid-solid phase mass transfer limitations. All the kinetic runs have been interpreted with a mathematical model adopting the kinetics previously developed by the authors using a well-stirred batch reactor. For both the reactors, the feasibility of a pseudocontinuous operation has also been successfully tested.