Arylsulfonic Acid Research Articles

Polymerization of ethylene with (nBuCp)2ZrCl2 supported over mesoporous SBA-15 functionalized with sulfonic acid groups

The polymerization of ethylene in n-heptane with (nBuCp)2ZrCl2 supported over mesoporous SBA-15 catalysts functionalized with propyl or aryl sulfonic acid groups and impregnated with either MAO or TMA was investigated and compared with reference samples. All the supports showed mesoscopic ordering with pore sizes of 7.8–6.6nm, BET surface areas around 700m2g−1, sulfonic acid loadings between 10 and 20 wt% and an acidity of roughly 1–1.7mmol H+g−1. None of the catalysts were capable of polymerizing ethylene in the absence of MAO in spite of using TMA or TIBA as scavengers. The addition of MAO (Al/Zr=800 or 5000) led towards ethylene polymerization, being the activity dependent on Al/Zr molar ratio (higher for Al/Zr=5000). The catalysts treated with TMA during the impregnation exhibited considerable leaching, unlike those treated with MAO wherein the leaching was low (<9 wt%). The presence of the sulfonic acid moiety enhanced the activity of the catalysts. In addition, the activity was also augmented with the increase of the sulfonic acid content from 10 to 20 wt%. Interestingly, the molecular weight of the polyethylene synthesized with the SBA-15 functionalized with sulfonic acid groups were 1.5–2.5 times higher, especially with the propyl moiety which leads towards Mw∼350,000gmol−1 at 1.2barg. The results were explained through an interaction between the sulfonic acid moiety and the chlorinated MAO species, which activates the metallocene.

Effective and Selective Bisphenol A Synthesis on a Layered Silicate with Spatially Arranged Sulfonic Acid

The silylated derivatives of a layered alkali silicate, magadiite, modified with propylsulfonic or arylsulfonic acid were synthesized and used as catalysts for an acid-catalyzed condensation of phenol with acetone. The propylsulfonated magadiites with a different amount of the attached silyl group were synthesized by the silylation of the dodecylammonium-exchanged magadiite with the tuned amount of 3-(mercaptopropyl)trimethoxysilane and the subsequent oxidation of the attached thiol to sulfonic acid. The arylsulfonated magadiite was synthesized by the silylation of the dodecylammonium-exchanged magadiite with 2-(4-chlorosulfonylphenyl)ethyltrimethoxysilane and the subsequent hydrolysis of the attached sulfonyl chloride to sulfonic acid. The X-ray diffraction (XRD) patterns and elemental mappings of the products, and the photoluminescent spectra of the Eu(3+)-exchanged products suggested that propylsulfonic or arylsulfonic acid was homogeneously distributed in the interlayer space. When all the sulfonated materials were used as an acid catalyst for condensation between phenol and acetone, p,p' bisphenol A selectively formed over the o,p' isomer, and higher yield and selectivity were attained on the catalysts with larger amount of the attached sulfonic acid. When the interlayer space of the propylsulfonated magadiite was expanded by the co-attachment of octadecylsilyl group, lower selectivity was obtained. The arylsulfonated magadiite showed considerably higher p,p' bisphenol A yield than the propylsulfonated magadiites.

Aryl sulfonic acid catalyzed hydrolysis of cellulose in water

Catalytic activities of eight alkyl/aryl sulfonic acids in water were compared with sulfuric acid of the same acid strength (0.0321mol H+ ion/L) for hydrolysis of Sigmacell cellulose (DP∼450) in the 140–190°C temperature range by measuring total reducing sugar (TRS), and glucose produced. Cellulose samples hydrolyzed at 160°C for 3h, in aqueous p-toluenesulfonic acid, 2-naphthalenesulfonic acid, and 4-biphenylsulfonic acid mediums produced TRS yields of 28.0, 25.4, and 30.3% respectively, when compared to 21.7% TRS produced in aqueous sulfuric acid medium. The first order rate constants at 160°C in different acid mediums correlated with octanol/water distribution coefficient logD of these acids, except in the case of highly hydrophobic 4-dodceylbenzenesulfonic acid. In the series of sulfonic acids studied, 4-biphenylsulfonic acid appears to be the best cellulose hydrolysis catalyst.

Carbocatalytic dehydration of xylose to furfural in water

Graphene, graphene oxide, sulfonated graphene, and sulfonated graphene oxide (SGO) have been prepared, characterized and tested for the dehydration of xylose to furfural in water. In particular, SGO was proven to be a rapid and water-tolerant solid acid catalyst even at very low catalyst loadings down to 0.5 wt.% vs xylose, maintaining its initial activity after 12 tested repetitions at 200 °C, with an average yield of 61% in comparison to 44% for the uncatalyzed system. Raman spectroscopy, energy dispersive X-ray spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, 13C solid state nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy and surface area analysis suggested that the aryl sulfonic acid groups were the key active sites for high temperature production of furfural in water. They were more thermally stable under the reaction conditions and acidic than other functional groups attached to the graphene surface.

Nanoscale Organization of Thiol and Arylsulfonic Acid on Silica Leads to a Highly Active and Selective Bifunctional, Heterogeneous Catalyst

Ordered mesoporous silicas functionalized with alkylsulfonic acid and thiol group pairs have been shown to catalyze the synthesis of bisphenols from the condensation of phenol and various ketones, with activity and selectivity highly dependent on the distance between the acid and thiol. Here, a new route to thiol/sulfonic acid paired catalysts is reported. A bis-silane precursor molecule containing both a disulfide and a sulfonate ester bond is grafted onto the surface of ordered mesoporous silica, SBA-15, followed by simultaneous disulfide reduction and sulfonate ester hydrolysis. The resulting catalyst, containing organized pairs of arylsulfonic acid and thiol groups, is significantly more active than the alkylsulfonic acid/thiol paired catalyst in the synthesis of bisphenol A and Z, and this increase in activity does not lead to a loss of regioselectivity. The paired catalyst has activity similar to that of a randomly bifunctionalized arylsulfonic acid/thiol catalyst in the bisphenol A reaction but exhibits greater activity and selectivity than the randomly bifunctionalized catalyst in the bisphenol Z reaction.

A discrete unsymmetrically substituted dihydrodioxadistannetane with both η 1 and intramolecular η 2μ 2 sulfonate bondings

Hydrolysis of the aryltripropynyltin ( 3) in the presence of an arylsulfonic acid resulted in the formation of a new tetrasulfonato 1,3-dihydro-1,3-dioxa-2,4-diaryl-2,4-distannetane ( 4). Its crystal structure revealed that the molecule is the smallest discrete tin sulfonate cluster reported up to now with absence of intermolecular interactions. Molecule 4 also exhibits unusual η 1 and intramolecular η 2μ 2 bonding modes for the sulfonate groups. Moreover, while only symmetrical 1,3-dihydro-1,3-dioxa-distannetanes have been described so far, the tin atoms in 4 are differently substituted.

Electron-Beam-Induced Color Imaging of Acid-Chromic Polymer Films

Polymer films with acid-responsive chromic dyes and acid generators have been designed for an electron-beam (EB)-induced color imaging system. Arylsulfonic acid esters and triphenylsulfonium salts were used as an EB-sensitive acid generator; the acid (H+) allows a chromic reaction with rhodamine B base (RB) and 4,4′-bis(dimethylamino)benzhydrol (BH) to be triggered. Upon EB irradiation, poly(methyl methacrylate) (PMMA) films consisting of RB or BH and acid generators exhibited a characteristic absorption band with λmax at 560 and at 612 nm, respectively, and an isosbestic point. These spectral changes clearly indicate that colorless chromic dyes in PMMA are transformed selectively to the colored form. The color imaging of these films was performed by electron-beam direct writing (EBDW) with a 50 nm diameter beam to form 100−1000 nm line and space patterns and evaluated by optical and confocal laser microscopy. EBDW on the acid-chromic polymer films, especially for BH, yielded clear color imaging of 100−20...

Functionalization of SWNTs to facilitate the coordination of metal ions, compounds and clusters

The carboxylate residues of the open ends of aryl-tert-butyl and arylsulfonic acid side-walled functionalized single walled carbon nanotubes (SWNTs) have been investigated for the complexation conditions of the iron-molybdenum cluster [H(x)PMo(12)O(40)CH(4)Mo(72)Fe(30)(O(2)CMe)(15)O(254)(H(2)O)(98)] ("FeMoC"). A range of alternative donor groups for the attachment of FeMoC have been investigated for piranha etched SWNTs, dodecyl side-walled functionalized SWNTs (DD-SWNTs) and ultra-short SWNTs (US-SWNTs), including include pyridines, thiols and phosphines, using coupling reactions to either the carboxylate or hydroxide residues of the SWNTs' open ends. The functionalized SWNTs have been characterized by XPS, uptake of Fe(3+) and, where appropriate, MAS (31)P NMR. The efficacy of binding is dependent on the presence and identity of the ligand moiety. TEM and AFM of the SWNT-FeMoC conjugates show the presence of a 2-3 nm spherical feature on the tip of individual SWNTs.

Synthesis, Structure and Reactivity of Hydrated and Dehydrated Organotin Cations

AbstractMonomeric organotin dications {[nBu2Sn(H2O)4]2+·2C6H5SO3–} and {[nBu2Sn(H2O)4]2+·1,5‐C10H6(SO3–)2} have been synthesized by the reaction of [nBu2SnO]n and the corresponding arylsulfonic acid. Dodecanuclear organooxotin macrocations {[(nBuSn)12(μ3‐O)14(μ2‐OH)6]2+·2RSO3–} (R = C6H5; 2,5‐Me2C6H3) have been synthesized by the reaction of nBuSn(O)(OH) and the corresponding arylsulfonic acid. The X‐ray crystal structure of one of the dodecanuclear cages is reported. These organotin cations have been shown to be effective catalysts in acetylation and transacetylation reactions. (© Wiley‐VCH Verlag GmbH &amp; Co. KGaA, 69451 Weinheim, Germany, 2006)

Grafting of 4‐Hydroxybenzenesulfonic Acid onto Commercially Available Poly(VDF‐co‐HFP) Copolymers for the Preparation of Membranes

AbstractThe grafting of a phenate bearing sulfonate group in solution onto commercially available poly(VDF‐co‐HFP) copolymers, where VDF and HFP stand for vinylidene fluoride and hexafluoropropene, respectively, is presented. This reaction leads to novel fluoropolymers, bearing aryl sulfonic acid side functions, which are fuel cell membrane precursors. A mechanism similar to the grafting of bisphenol onto VDF‐containing copolymers is discussed. First, the sulfonate phenate is modified to give the didecyldimethylammonium bromide sulfonate phenate salt, in order to promote the substitution onto a fluorine atom in VDF unit adjacent to one HFP unit onto a fluorine atom in the copolymer. The substitution of this salt onto the fluorinated copolymer yields low molar percentages of grafted phenate, ranging from 1.8 to 5.1 mol‐%, whereas it reaches values up to 13 mol‐% grafting when the NH2‐CH2‐CH2‐S‐CH2‐CH2‐C6H4‐SO3Na amine is used as the grafting agent. NMR characterization is used to monitor the grafting process. The electrochemical properties of the resulting phenate grafted‐poly(VDF‐co‐HFP) copolymer are studied. The theoretical ion exchange capacities are half that of Nafion®. The proton conductivities are also lower than that of Nafion®, although one conductivity measurement reached a value of 5.1 mS cm–1, showing a non‐negligible conductivity. The water uptake is lower than these noted for a sulfonated amine‐grafted copolymer, and is of the same order as that for Nafion®. Finally, it is shown that these novel materials start to decompose above 200 °C, showing a similar thermostability as that of an amino‐containing aryl sulfonate‐grafted poly(VDF‐co‐HFP) copolymer.

Catalytic Polymerization and Facile Grafting of Poly(furfuryl alcohol) to Single-Wall Carbon Nanotube: Preparation of Nanocomposite Carbon

A nanocomposite carbon was prepared by grafting a carbonizable polymer, poly(furfuryl alcohol) (PFA), to a single-wall carbon nanotube (SWNT). The SWNT was first functionalized with arylsulfonic acid groups on the sidewall via a method using a diazonium reagent. Both Raman and FTIR spectroscopies were used to identify the functional groups on the nanotube surface. HRTEM imaging shows that the SWNT bundles are exfoliated after functionalization. Once this state of the SWNTs was accomplished, the PFA-functionalized SWNT (PFA-SWNT) was prepared by in situ polymerization of furfuryl alcohol (FA). The sulfonic acid groups on the surface of the SWNT acted as a catalyst for FA polymerization, and the resulting PFA then grafted to the SWNTs. The surfaces of the SWNTs converted from hydrophilic to hydrophobic when they were wrapped with PFA. The formation of the polymer and the attraction between it and the sulfonic acid groups were confirmed by IR spectra. A nanocomposite carbon was generated by heating the PFA-SWNT in argon at 600 degrees C, a process during which the PFA was transformed to nanoporous carbon (NPC) and the sulfonic acid groups were cleaved from the SWNT. Based upon the Raman spectra and HRTEM images of the composite, it is concluded that SWNTs survive this process and a continuous phase is formed between the NPC and the SWNT.

Ether Aryl Sulfonic Acid Esters with Improved Antimalarial/Anticancer Activities

Our previous report showed that our current benchmark agent, 4-methoxyphenyl p-toluenesulfonate, is a selective antimalarial/anticancer agent. A series of related sulfones and sulfonic acid esters is now examined. 4-Allyloxyphenyl p-toluenesulfonate is a superior antimalarial/anticancer agent. 4-Methoxyphenyl 4-nitrobenzenesulfonate is a superior antimalarial agent, but shows poorer inhibition of human skin cancer cells.

Preparation and Characterization of NPC/SWNT Nanocomposite

ABSTRACTA nanocomposite carbon composed with single wall carbon nanotube (SWNT) and nanoporous carbon (NPC) was prepared by grafting a carbonizable polymer, poly(furfuryl alcohol) (PFA) to a SWNT. The SWNT was first functionalized with arylsulfonic acid groups on sidewall (SA-SWNT) and then converted to PFA-functionalized SWNT (PFA-SWNT) by in situ polymerization of furfuryl alcohol (FA). SWNT/NPC nanocomposite carbon was generated by heating PFA-SWNT in argon at 600°C. A continuous phase was formed between SWNT and NPC. The deformation of the nanocomposite carbon at high temperature was studied by heating it at temperatures from 1200 to 2000 °C and characterized with HRTEM and Raman spectra. It was found that NPC tended to graphitize along the axis of neighboring nanotubes at temperature higher than 1400°C. Complete graphitization of NPC and SWNTs was obtained at 2000 °C, when the NPC transformed to graphitic nanoribbon (GNR) and SWNT or DWNT collapsed within the confines of the GNR. Nanocomposite polymer and carbon fibers were prepared by dispersing small amount of SA-SWNT in FA, followed with polymerization, thermosetting and pyrolysis. The composite polymer fibers' Young's modulus was lower than the pure PFA fibers prepared at the same conditions. However, after heated in argon at 300 °C, 400 °C, 500 °C and 600 °C respectively, the Young's modulus of the nanocomposite carbon fibers turned to be higher than the fibers derived from pure PFA and the enhancement by SWNT increase with increasing temperature. For the nanocomposite carbon fibers treated at 600 °C, the fibers had ∼20% increase of Young's modulus over the fibers from pure PFA with only 0.1wt% of SA-SWNT in FA.

Direct Sulfonylation of Aromatic Rings with Aryl or Alkyl Sulfonic Acid Using Supported P2O5/Al2O3.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Direct Sulfonylation of Aromatic Rings with Aryl or Alkyl Sulfonic Acid Using Supported P2O5/Al2O3

Direct sulfonylation of aromatic rings with aryl or alkyl sulfonic acid supported P2O5/Al2O3 (w/w 50%) under heterogeneous conditions in short reaction time and high yields.

Sulfonate-bonded tin complexes for the production of diphenyl carbonate

Various tin complexes including dibutyltin oxide and dibutyltin diacetate were tested for their activities in the transesterification between dimethyl carbonate (DMC) and phenol to produce diphenyl carbonate (DPC). The activities of tin complexes were significantly enhanced by the co-presence of alkyl or arylsulfonic acid, possibly due to the in situ formation of sulfonate-bonded tin complexes. Highly active triflate-bonded tin species, [Bu 2Sn(OH)(OTf)] 2 and [Bu 2Sn(OAc)(OTf)] 2, were isolated from the reaction of triflic acid with dibutyltin oxide and dibutyltin diacetate, and characterized by single crystal X-ray diffraction study.

Electron-Beam-Induced Fries Rearrangement and Oxidation Reactions of Sulfonic Acid Esters in Crystalline State

The electron beam (EB)-induced reactions of arylsulfonic acid esters, phenyl p-toluenesulfonate (1a), phenyl benzenesulfonate (1b), and phenyl 1-naphthalenesulfonate (1c), were examined in the balk state. The EB irradiation of 1a afforded the Fries rearrangement products, o- and p-hydroxyphenyl p-tolylsulfoes (2a and 3a), phenol (5) and the oxidation products of 2a, o,p-dihyroxyphenyl p-tolysulfon (4a), which has not been observed in photolysis. The EB-induced reaction of 1a exhibits higher ortho-regioselectivity at the early stage owing to crystal lattice control. The radiation of 1b, which is liquid at room temperature, give Fries rearrangement products with lower ortho/para regioselectivity. On the other hand, the EB-induced reaction of 1c proceeded with the lowest reactivity through crystal to crystal transformation to afford Fries rearrangement products, o- and p-hydroxyohenyl 1-naphthylsulfones (2c and 3c), and 5, but not oxidation product. The mechanistic study reveals that oxidation rpoduct 4a generated by the oxidation reaction of ortho-Fries rearrangement product 2a but not para-isomer 3a with an active oxidant, which should result from the decomposition of 1a.

Role of sulfonic acids in the Sn-catalyzed transesterification of dimethyl carbonate with phenol

Diphenyl carbonate, the key intermediate of the non-phosgene polycarbonate manufacturing process, can be produced by the transesterification of dimethyl carbonate with phenol in the presence of dibutyltin oxide. The use of an alkyl or aryl sulfonic acid in conjunction with dibutyltin oxide significantly enhances the activity of dibutyltin oxide. 19 F and 119 Sn NMR studies suggest the formation of tin complex containing strongly electrophilic sulfonate ligand from the reaction of dibutyltin oxide with alkyl or aryl sulfonic acid. Various factors affecting the transesterification of dimethyl carbonate with phenol were investigated.

Design of heterogeneous catalysts via multiple active site positioning in organic-inorganic hybrid materials.

Catalytic materials bearing multiple sulfonic acid functional groups and positioned at varying distances from one another on the surface of mesoporous solids are prepared to explore the effects that the spatial arrangement of active sites have on catalytic activity and selectivity. A series of organosiloxane precursors containing either disulfide or sulfonate ester functionalities (synthons of the eventual sulfonic acid groups) are synthesized. From these molecular precursors, a variety of organic-inorganic hybrid, mesostructured SBA-15 silica materials are prepared using a postsynthetic grafting procedure that leads to disulfide and sulfonate ester modified silicas: [Si]CH(2)CH(2)CH(2)SS-pyridyl, 2.SBA, [Si]CH(2)CH(2)CH(2)SSCH(2)CH(2)CH(2)[Si], 3.SBA, [Si]CH(2)CH(2)(C(6)H(4))(SO(2))OCH(2)CH(3), 4.SBA, and [Si]CH(2)CH(2)(C(6)H(4))(SO(2))OC(6)H(4)O(SO(2))(C(6)H(4))CH(2)CH(2)[Si], 6.SBA ([Si] = (tbd1;SiO)(x)()(RO)(3)(-)(x)()Si, where x = 1, 2). By subsequent chemical derivatization of the grafted species, thiol and sulfonic acid modified silicas are obtained. The materials are characterized by a variety of spectroscopic ((13)C and (29)Si CP MAS NMR, X-ray diffraction) and quantitative (TGA/DTA, elemental analysis, acid capacity titration) techniques. In all cases, the organic fragment of the precursor molecule is grafted onto the solid without measurable decomposition, and the precursors are, in general, attached to the surface of the mesoporous oxide by multiple siloxane bridges. The disulfide species 2.SBA and 3.SBA are reduced to the corresponding thiols 7.SBA and 8.SBA, respectively, and 4.SBA and 6.SBA are transformed to the aryl sulfonic acids 11.SBA and 12.SBA, respectively. 7.SBA and 8.SBA differ only in terms of the level of control of the spatial arrangement of the thiol groups. Both 7.SBA and 8.SBA are further modified by oxidation with hydrogen peroxide to produce the alkyl sulfonic acid modified materials 9.SBA and 10.SBA, respectively. The performances of the sulfonic acid containing SBA-15 silica materials (with the exception of 12.SBA) are tested as catalysts for the condensation reaction of phenol and acetone to bisphenol A. The alkyl sulfonic acid modified material 10.SBA derived from the cleavage and oxidation of the dipropyl disulfide modified material 3.SBA is more active than not only its monosite analogue 9.SBA, but also the presumably stronger acid aryl sulfonic acid material 11.SBA. It appears that a cooperative effect between two proximal functional groups may be operating in this reaction.

Novel chemistry of alpha-tosyloxy ketones: applications to the solution- and solid-phase synthesis of privileged heterocycle and enediyne libraries.

New synthetic technologies for the preparation and elaboration of alpha-tosyloxy ketones in solution- and on solid-phase are described. Both olefins and ketones serve as precursors to these relatively stable chemical entities: olefins via a novel one-pot epoxidation, arylsulfonic acid displacement, and oxidation sequence, and ketones by direct exposure to arylsulfonic acids in the presence of diacetoxy iodobenzene. Reaction of these substrates with O-, S-, or N-centered nucleophiles leads to incorporation of the nucleophile with concomitant expulsion of the sulfonate, while exposure to bis-functional nucleophiles furnishes annulated heterocyclic systems. In addition, the reactions of carbon-centered nucleophiles with alpha-tosylyloxy ketones are also explored. The collated data for all these nucleophiles provide compelling evidence for the proposal that different reaction pathways are followed when alpha-tosyloxy ketones are engaged by "hard" versus "soft" nucleophiles. The accessibility and site-selectivity of the chemistry demonstrated herein offer the promise of an expanded use for this moiety in solid-phase library construction, in particular, and in the field of organic synthesis, in general.