Acid-functionalized SBA-15 Research Articles

Beta zeolite as an efficient catalyst for the synthesis of diphenolic acid (DPA) from renewable levulinic acid

The solvent-free production of diphenolic acid (DPA) from levulinic acid (LA) and phenol is studied using readily accessible commercial acid zeolites like Beta, ZSM-5 and USY. Acid zeolites are cost-effective catalysts, and they are herein benchmarked against the sulfonic acid resins Amberlyst-15 and Nafion®, and sulfonic acid-functionalized SBA-15 silicas. Beta zeolite with a moderate aluminum content (H-Beta 19, Si/Al=23) presents the best catalytic performance, owing to the right combination of the shape selectivity effect conferred by the BEA structure, and the adequate balance of acidity (Al content and speciation). The optimization of the reaction conditions is tackled by the response surface methodology using as optimization factors the temperature, the PhOH:LA molar ratio, and the catalyst loading. Thus, under the optimized reaction conditions (12 mmol LA, 140 ᵒC, 0.30 g catalyst loading, PhOH:LA = 6:1 mol), over 70% yield to DPA with LA conversion around 77% is obtained after 72 h. Despite the catalyst shows a progressive activity decay in successive uses because of fouling, removal of the formed organic deposits by calcination in air allows restoring the starting catalytic performance.

Efficient removal of lead and copper ions in aqueous solution by glutamic acid-functionalized SBA-15

Efficient removal of lead and copper ions in aqueous solution by glutamic acid-functionalized SBA-15

Sulfonic Mesostructured SBA-15 Silicas for the Solvent-Free Production of Bio-Jet Fuel Precursors via Aldol Dimerization of Levulinic Acid

Sulfonic acid-functionalized mesostructured silicas have been evaluated in the solvent-free aldol dimerization of biomass-derived levulinic acid into bio-jet fuel precursors. These compounds produce branched alkanes in a subsequent hydrodeoxygenation process, with suitable properties for being a renewable alternative to conventional fossil aviation fuels. The combination of activity and selectivity toward the desired condensation products achieved over sulfonic acid-functionalized SBA-15 materials is superior to those displayed by other commercial solid acid catalysts. Enhanced textural properties provided by the mesoporous SBA-15 support contribute to such improved catalytic performance. The strength and loading of the mesoporous silica-supported sulfonic acid moieties are also important factors affecting the catalytic performance of the materials. Reaction conditions (temperature, time, and catalyst loading) have been optimized for propylsulfonic acid-functionalized mesostructured silica (Pr-SBA-15) by means of a response surface methodology, leading to a maximum yield to levulinic acid dimerization products of 58.4% (145 °C, 0.15 g of catalyst, 24 h, no solvent). Under these reaction conditions, conversion of levulinic acid is 61.1%, indicating excellent selectivity toward bio-jet fuel precursors. A small catalytic activity decay has been detected in reutilization experiments, attributed to the formation of organic deposits onto the catalyst surface. A mild acid washing of the catalyst allowed a significant recovery of the initial activity.

Sulfonic Acid-Functionalized SBA-15 as Strong Cation-Exchange Sorbent for Solid-Phase Extraction of Atropine and Scopolamine in Gluten-Free Grains and Flours.

A novel method was developed and applied to the determination of the most representative tropane alkaloids (TAs), atropine and scopolamine, in gluten-free (GF) grains and flours by HPLC-MS/MS. Accordingly a suitable sample treatment procedure based on solid-liquid extraction (SLE) and followed by strong cation-exchange solid-phase extraction (SCX-SPE) was optimized. SBA-15 mesostructured silica functionalized with sulfonic acids was evaluated as sorbent. The proposed method was fully validated in sorghum flour showing good accuracy with recoveries in the range of 93–105%, good linearity (R2 > 0.999) and adequate precision (RSD < 20%). Low method quantification limits (MQL) were obtained (1.5 and 2.4 µg/kg for atropine and scopolamine, respectively) and no matrix effect was observed thanks to the extraction and clean-up protocol applied. The method was applied to 15 types of GF samples of pseudocereals (buckwheat, quinoa and amaranth), cereals (teff, corn and blue corn, sorghum and millet) and legumes (red and green lentil, chickpea and pea). Atropine was found above the MQL in eight of them, with values between 7 and 78 µg/kg, while scopolamine was only found in teff flour, its concentration being 28 µg/kg. The method developed is an interesting tool for determining TAs in a variety of samples of GF grains and flours.

Preparation of Phosphoric Acid-Functionalized SBA-15 and Its High Efficient Selective Adsorption Separation of Lanthanum Ions

Phosphoric acid-functionalized mesoporous silica material was prepared by copolycondensation using P123 as the soft template and diethylphosphatoethyltriethoxysilane as the functional monomer. It w...

Selective production of 5-hydroxymethylfurfural from fructose in the presence of an acid-functionalized SBA-15 catalyst modified with a sulfoxide polymer

A bifunctional catalyst design incorporating acid sites and DMSO-like polymers increases the selectivity for fructose dehydration to HMF.

Efficient Production of Medium-Chain Structured Phospholipids over Mesoporous Organosulfonic Acid-Functionalized SBA-15 Catalysts

It is highly desirable that efficient recoverable heterogeneous catalysts should be developed to replace the costly biocatalysts used in producing structured phospholipids (SPLs) with medium-chain fatty acids (MCFAs). Thus, mesoporous propyl and phenyl sulfonic acid-functionalized SBA-15 materials synthesized via surface modification methods were investigated for the soybean lecithin interesterification with methyl caprate or caprylate. The physicochemical properties of the synthesized solid acids were deeply studied by small-angle X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared and pyridine adsorption, etc. to build the possible structure–performance relationships. The results revealed that amounts of organosulfonic acid groups were successfully grafted onto the SBA-15 support, and most of the surface acid sites contained in the as-prepared organic–inorganic hybrid samples were assigned as strong Brӧnsted acid sites. Notably, the functionalized SBA-15 materials exhibited promising catalytic behaviors in producing MCFA-enriched SPLs under mild conditions (40 °C, 6 h) when compared with commercial Amberlyst-15 and typical phospholipases or lipases, mostly due to their high surface area, ordered structure and adequate Brӧnsted acid sites. Besides, the as-prepared materials could be easily recycled five times without obvious deactivation. This work might shed light on alternative catalysts for SPL production instead of the costly enzymes.

Catalytic Applications of Large Pore Sulfonic Acid-Functionalized SBA-15 Mesoporous Silica for Esterification

Abstract We report the preparation of pore expanded and sulfonic acid functionalized mesoporous silica catalysts by using different kinds of swelling agents such as 1,3,5-trimethyl benzene (TMB), n-decane (D), n-tridecane (TD), and n-hexadecane (HD) at two different ratios of swelling agent/surfactant. Non-swelled mesoporous silica catalyst, SBA-15-SO3H, was also prepared for comparison. The performance of the sulfonic acid functionalized solid acid catalysts by using one-pot synthesis procedure was evaluated in terms of their catalytic activity in the esterification of propionic acid with methanol. The catalysts have been characterized by X-ray diffraction to investigate the phase transition between the hexagonally packed arrangement of cylindrical pores and mesocellular silica foams (MCF), and N2 adsorption/desorption technique in terms of pore size and distributions. It was concluded from the XRD and N2 adsorption/desorption analyses that hexagonally packed and cylindrical pore structure is maintained only for low ratio of swelling agent/surfactant and the increase of the dimension of a template micelle is accompanied by an increase in structural disruption, which was attributed to the phase transition from highly ordered hexagonal arrangement to mesocellular foam (MCF) phase with large nodded pore structures rather than cylindrical pores. Among the different swelling agents, TMB and D were found to be effective for the increase in pore diameter (up to 8 and 7.8 nm), whereas, TD and HD (6.6 nm) are effective to maintain the ordered X-ray diffraction patterns resulting mesoporous materials without giving enlargement of pore diameter in comparison with TMB and D. Pore expanded catalysts, SBA-15-SO3H-TMB-0.1 and SBA-15-SO3H-D-0.1, exhibit 68 and 43% enhancement in turnover frequency toward propionic acid methanol esterification, respectively, over non-swelled SBA-15-SO3H, despite possessing similar acid strengths. The increased activity especially for SBA-15-SO3H-TMB-0.1 and SBA-15-SO3H-D-0.1 likely reflects the accessibility to the active sulfonic acid sites as well as acidity.

Intraparticle Diffusional versus Site Effects on Reaction Pathways in Liquid-Phase Cross Aldol Reactions.

Chemo- and regioselectivity in a heterogeneously catalyzed cross aldol reaction were directed by tuning the nature of the sites, textural properties, and reaction conditions. Catalysts included sulfonic acid-functionalized resins or SBA-15 with varying particle size or pore diameter, H-BEA zeolites, and Sn-BEA zeotype; conditions were 25 °C to 170 °C in organic media. Benzaldehyde and 2-butanone yielded branched (reaction at -CH2 - of butanone) and linear (reaction at -CH3 ) addition and condensation products; and fission of the branched aldol led to β-methyl styrene and acetic acid. Strong acids promoted the dehydration step, and regioselectivity originated from preferred formation of the branched aldol. Both, resins and functionalized SBA-15 materials yielded predominantly the branched condensation product, unless particle morphology or temperature moved the reaction into the diffusion-limited regime, in which case more fission products were formed, corresponding to Wheeler Type II selectivity. For H-form zeolites, fission of the branched aldol competed with dehydration of the linear aldol, possibly because weaker acidity or steric restrictions prevented dehydration of the branched aldol.

Corrigendum: Acid‐Functionalized Mesoporous SBA‐15 as an Efficient Heterogeneous Organocatalyst for the Green Synthesis of β‐Amino Alcohol Derivatives

ChemistrySelectVolume 2, Issue 8 p. 2588-2588 CorrigendumFree Access Corrigendum: Acid-Functionalized Mesoporous SBA-15 as an Efficient Heterogeneous Organocatalyst for the Green Synthesis of β-Amino Alcohol Derivatives This article corrects the following: Acid-Functionalized Mesoporous SBA-15 as an Efficient Heterogeneous Organocatalyst for the Green Synthesis of β-Amino Alcohol Derivatives Swarbhanu Ghosh, Piyali Bhanja, Rostam Ali Molla, Resmin Khatun, Sk. Manirul Islam, Volume 2Issue 6ChemistrySelect pages: 2159-2165 First Published online: February 27, 2017 Swarbhanu Ghosh, Swarbhanu GhoshSearch for more papers by this authorPiyali Bhanja, Piyali Bhanja +91-33-2473-4971 | Fax: +91-33-2473-2805 Search for more papers by this authorRostam Ali Molla, Rostam Ali MollaSearch for more papers by this authorResmin Khatun, Resmin KhatunSearch for more papers by this authorProf. Sk. Manirul Islam, Prof. Sk. Manirul Islam +91-33-2582-8750 | Fax: +91-33-2582-8282 Search for more papers by this author Swarbhanu Ghosh, Swarbhanu GhoshSearch for more papers by this authorPiyali Bhanja, Piyali Bhanja +91-33-2473-4971 | Fax: +91-33-2473-2805 Search for more papers by this authorRostam Ali Molla, Rostam Ali MollaSearch for more papers by this authorResmin Khatun, Resmin KhatunSearch for more papers by this authorProf. Sk. Manirul Islam, Prof. Sk. Manirul Islam +91-33-2582-8750 | Fax: +91-33-2582-8282 Search for more papers by this author First published: 22 March 2017 https://doi.org/10.1002/slct.201700564AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume2, Issue8March 13, 2017Pages 2588-2588 RelatedInformation

Synthesis of polyoxymethylene dimethyl ethers catalyzed by sulfonic acid-functionalized mesoporous SBA-15

Sulfonic acid-functionalized mesoporous SBA-15 with different sulfur loading was synthesized and used to investigate the catalytic performance for PODEn synthesis.

Hydration of DCPD over sulfonic acid-functionalized SBA-15 catalyst

Sulfonic acid-functionalized SBA-15 materials (SA-SBA-15) with ordered channeling pores were synthesized by one-pot co-condensation and used to catalyze the hydration of dicyclopentadiene (DCPD). The target product, cydecanol (DCPD-OH) has been used as a modifier for polyester or alkyd resin. Propylsulfonic acid functionalized SBA-15 was found to be more efficient than the silica gel counterpart or arylsulfonic acid functionalized material in catalyzing DCPD hydration to yield DCPD-OH. The DCPD conversion and DCPD-OH yield increased with the decrease in H2O/DCPD ratio. Optimal DCPD conversion and DCPD-OH selectivity were obtained with the molar composition of DCPD:H2O:H+-catalyst=1:30:0.1.

Modeling of boldine alkaloid adsorption onto pure and propyl-sulfonic acid-modified mesoporous silicas. A comparative study

The present study deals with the adsorption of boldine onto pure and propyl-sulfonic acid-functionalized SBA-15, SBA-16 and mesocellular foam (MCF) materials. Siliceous adsorbents were characterized by nitrogen sorption analysis, transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier-transform infrared (FT-IR) spectroscopy and thermogravimetric analysis. The equilibrium adsorption data were analyzed using the Langmuir, Freundlich, Redlich-Peterson, and Temkin isotherms. Moreover, the Dubinin-Radushkevich and Dubinin-Astakhov isotherm models based on the Polanyi adsorption potential were employed. The latter was calculated using two alternative formulas including solubility-normalized (S-model) and empirical C-model. In order to find the best-fit isotherm, both linear regression and nonlinear fitting analysis were carried out. The Dubinin-Astakhov (S-model) isotherm revealed the best fit to the experimental points for adsorption of boldine onto pure mesoporous materials using both linear and nonlinear fitting analysis. Meanwhile, the process of boldine sorption onto modified silicas was described the best by the Langmuir and Temkin isotherms using linear regression and nonlinear fitting analysis, respectively. The values of adsorption energy (below 8kJ/mol) indicate the physical nature of boldine adsorption onto unmodified silicas whereas the ionic interactions seem to be the main force of alkaloid adsorption onto functionalized sorbents (energy of adsorption above 8kJ/mol).

Propylsulfonic and arenesulfonic functionalized SBA-15 silica as an efficient and reusable catalyst for the acidolysis of soybean oil with medium-chain fatty acids

The objective of this work was to develop a feasible ecofriendly process to produce medium-chain fatty acid (MCFA)-enriched structured lipids (SLs) in heterogeneous manners. For this purpose, the propyl-SO3H or arene-SO3H-modified SBA-15 materials were prepared through a surface functionalization of SBA-15 silica with propyl-SO3H and arene-SO3H groups. The organosulfonic acid-functionalized SBA-15 materials were characterized by Brönsted acidity determination, elemental analysis, XRD, C13 MAS NMR, FT-IR, SEM, TG, TEM, and N2 adsorption-desorption techniques. Results showed that the propyl-SO3H and arene-SO3H groups were successfully tethered on the SBA-15 support, and the ordered mesoporous structure of SBA-15 silica was well retained after the organofunctionalization. This organic-inorganic hybrid material displayed high surface acidities and high activities in the acidolysis of soybean oil with caprylic or capric acid to produce SLs containing MCFAs. The influences of processing parameters on the reaction were investigated. The two studied catalysts showed an excellent recyclability for the reaction.

Acid-functionalized mesoporous carbons for the continuous production of 5-hydroxymethylfurfural

The stability of solid acid catalysts is essential in the development of sustainable biomass conversion processes. Herein, we study the activity and stability of acid-functionalized periodic mesoporous carbons (CMK-3 and CMK-5) for the continuous production of 5-hydroxymethylfurfural from fructose. The acid-functionalized mesoporous carbon catalysts show comparable selectivities and turnover frequency (TOF) to that of propylsulfonic acid functionalized SBA-15. However, the first-order deactivation rate coefficient of the carbon-based materials are up to 60 times more stable than that for the acid-functionalized SBA-15 catalyst and up to 3 times more stable than commercial Nafion SAC-13. Of the catalysts studied, phenylsulfonic acid CMK-5 showed both the highest TOF for HMF production and lowest deactivation rate coefficient.

Heterogeneous Synthesis of Indole-2-Carboxylic Esters Via Bischler Cyclization Under the Catalysis of Sulfonic Acid-Functionalized SBA-15 Silicas

Phenylsulfonic acid-functionalized SBA-15 silica was found to be an efficient heterogeneous acid catalyst in Bischler cyclization for the synthesis of indole-2-carboxylic esters. Under the optimized conditions, a wide range of substituted 4-nitrobenzyl 3-hydroxy-2-(N-methyl-N-arylamino)-2-enoates could be smoothly transformed to the corresponding 4-nitrobenzyl indole-2-carboxylates in excellent yields (87–99 %). Moreover, the catalyst could be conveniently recovered and reused at least four times without significant loss of catalytic activity.

ChemInform Abstract: Sulfonic Acid‐Functionalized Mesoporous Silica (SBA‐Pr‐SO3H) as Solid Acid Catalyst in Organic Reactions

AbstractReview: 251 refs.

Carboxylic acid-functionalized SBA-15 nanorods for gemcitabine delivery

The present study deals with the functionalization of mesoporous silica nanoparticles as drug delivery systems. Mono, di, and tri amino-functionalized SBA-15 nanorods were synthesized by post-grafting method using (3-aminopropyl) triethoxysilane, N-(2-aminoethyl-)3- aminopropyltrimethoxysilane, and 3-[2-(2-aminoethylamino) ethylamino] propyl trimethoxysilane, respectively. The carboxylic acid derivatives of the amino-functionalized samples were obtained using succinic anhydride. Tminopropyltrimethoxysilanehe obtained modified materials were investigated as matrixes for the anticancer drug (gemcitabine) delivery. The prepared samples were characterized by SAXS, N2 adsorption/desorption, SEM, transmission electron microscopy, thermogravimetric analysis, and FTIR and UV spectroscopies. The adsorption and release properties of all samples were studied. It was revealed that the adsorption capacity and release behavior of gemcitabine were highly dependent on the type of the introduced functional groups. The carboxylic acid-modified samples have higher loading content, due to the strong interaction with gemcitabine. The maximum content of deposited drug in the modified SBA-15 nanorods is close to 40 wt%. It was found that the surface functionalization leads toward significant decrease of the drug release rate. The carboxylic acid-functionalized samples have slower release rate in contrast with the amino-functionalized samples.

Transformation of non-edible vegetable oils into biodiesel fuels catalyzed by unconventional sulfonic acid-functionalized SBA-15

A real understanding of intrinsic acidity and catalytic property of unconventional and sulfonic acid-functionalized SBA-15 platelet catalysts synthesized with the aid of highly solvated Zr4+ salts (shortly termed SA-SBA-15-p) for transesterification of non-edible vegetable oils into biodiesel fuel (BDF) was reported, in comparison with conventional SBA-15 catalyst (shortly termed SBA-15-conv), unconventional SBA-15 platelet catalyst (shortly termed SBA-15-p) and commercial sulfonic resins of Amberlyst-15 and SAC-13. Thorough characterizations and catalytic study revealed that the content of fatty acid methyl ester (FAME) as the main component of BDF was increased in the order of SBA-15-conv<SAC-13<SBA-15-p<Amberlyst-15<5-25SA-SBA-15-p, which correlated closely with the loading, distribution, strength of acidic sites. Among them, the unconventional 15SA-SBA-15-p catalyst with proper loadings of propylsulfonic groups (1.15mmolS−1g−1) and superficial Zr4+ clusters (0.66mmolg−1) as a mixed solid Bronsted and Lewis acid, which had differential heat of NH3 adsorption in the range of 90–125kJmol−1, gave highest FAME content with low concentrations of byproducts, such as glycerides and free fatty acid (FFA). In addition to high water and FFA tolerance levels, the used 15SA-SBA-15-p catalyst could be easily regenerated by ethanol extraction and its high activity was maintain. By contrast, the SBA-15-conv catalyst without any Lewis and Bronsted acids had almost no activity in BDF synthesis. The unconventional SBA-15-p catalyst with superficial Zr4+ clusters as a pure solid Lewis acid gave a moderate FAME content accompanying with a high concentration of unreactive glycerides. Commercial sulfonic resins of Amberlyst-15 and SAC-13 with strongly phenylsulfonic and Nafion sulfonic groups as pure solid Bronsted acids gave moderate FAME contents accompanying with high concentrations of unreactive glycerides and unwanted FFA byproducts. Furthermore, they were significantly deactivated by water, FFA and regeneration treatment due to the poison and leaching of sulfonic groups and the decomposition of thermally unstable framework.

Production of Jatropha biodiesel fuel over sulfonic acid-based solid acids

Sulfonic acid-functionalized platelet SBA-15 mesoporous silica with an acid capacity of 2.44mmol H(+) g-cat(-1) (shortly termed 15SA-SBA-15-p) was one-pot synthesized by co-condensation method. When applied as solid acid catalyst in synthesis of Jatropha biodiesel fuel (BDF), the 15SA-SBA-15-p catalyst showed higher activity and resistances to water and free fatty acid (FFA) than commercial sulfonic resins of Amberlyst-15 and SAC-13. For the continuous Jatropha BDF production, a steady 75-78wt% of fatty acid methyl ester (FAME) content was obtained over 15SA-SBA-15-p catalyst at 150°C for 75h, whereas the Amberlyst-15 and SAC-13 catalysts were quickly deactivated due to the decomposition of thermally unstable framework and serious leaching of sulfonic acids. More importantly, the quality, stability and cold flow characteristic of Jatropha BDF synthesized by 15SA-SBA-15-p catalyst were better than those synthesized by Amberlyst-15 and SAC-13 catalysts, making the blending with petro-diesel an easy task.