Room-temperature synthesis of silicate mesoporous MCM-41-type materials: influence of the synthesis pH on the porosity of the materials obtained

In this work, a variety of highly substituted quinolines were readily synthesized via Friedlander annulation using Brönsted acid silica-based sulfonic acid as a modified catalyst under solventfree conditions at room temperature. This efficient procedure has the advantages of giving the target compounds in high yields, short reaction times, simple workup procedure, reusability of the catalyst, and environmentally benign conditions.

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“…Mesoporous MCM-41 and MCM-41-SO 3 H catalysts were prepared according to the literature procedures [27][28][29] .…”

Section: Resultsmentioning

confidence: 99%

Silica-based sulfonic acid (MCM-41-SO3H): a practical and efficient catalyst for the synthesis of highly substituted quinolines under solvent-free conditions at ambient temperature

Maleki¹,

Javanshir²,

Sharifi³

2014

10.5267/j.ccl

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“…Sulica was extracted from FA using prior experimental work by the authors [6]. The silicate solution was then concentrated by evaporation.…”

Section: Preparation Of Mcm41mentioning

confidence: 99%

“…This was because at lower pH the alumina remained in solution. The increase in alumina has been thought to be due to the lower polycondensation degree of the silicate species which leads to higher incorporation of the alumina species [6]. …”

Section: Effect Of Gelation Ph On Xrf Analysismentioning

confidence: 99%

Preparation of mesoporous silica (MCM41) and its use as an adsorbent for heavy metals for acid mine drainage

Falayi¹,

Ntuli²,

Sithole³

2016

WIT Transactions on Ecology and the Environment

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Potassium silicate solutions obtained were used as a source for MCM41. The preparation of MCM41 was affected by the gelation pH. A pH of 7 produced the purest MCM41 with an external surface area of 98,000 m . The MCM41 could be used as an adsorbent for heavy metals in AMD. A 4% m/v solid loading of MCM41 could remove 95.5, 97.3 and 99.6% of Ni, Cu and Fe respectively. The adsorption process was found to fit the Langmuir isotherm and pseudo second order kinetics. The Gibbs free energy of adsorption for all metals was below -20 kJ/mol for all metals. The enthalpy for Fe, Cu and Ni removal were 19.97, 21.40 and 16.44 kJ/mol respectively and thus endothermic. The entropy for the removal of Fe, Cu and Ni were found to75.6, 76.2 and 56.5 J/mol respectively showing the strong affinity of MCM41 for the metals. The process was also thermodynamically spontaneous with the spontaneity increasing with an increase in temperature.

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“…The MCM-41 and AlMCM-41 materials were synthesized by a room temperature method with some modification in the described procedure in the literature [22]. We used tetraethylorthosilicate (Teos, Merck, 800658) as a source of silicon and hexadecyltrimethylammonium bromide (HDTMABr, BDH, 103912) as a surfactant template for preparation of the mesoporous materials.…”

Section: Reagents and Sample Preparationmentioning

confidence: 99%

New Methylene Blue (NMB) Encapsulated in Mesoporous AlMCM‐41 Material and Its Application for Amperometric Determination of Ascorbic Acid in Real Samples

Sohrabnezhad

Pourahmad

2007

Electroanalysis

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New methylene blue (NMB) dye incorporated into AlMCM-41 surfactant-free and hybrid surfactant-AlMCM-41 mesophase. UV-vis evidence shows that new methylene blue dye protonated in both cases of zeolites. New methylene blue is electroactive in zeolites and their electrochemical activity has been studied by cyclic voltammetry and compared to that of NMB in aqueous solutions. New methylene blue molecules are not released to the solution during CV measurements and are accessible to H 3 O þ ions. The presence of surfactant affects the kinetics of the redox process through proton ions diffusion. The midpoint potentials (E m ) values show that new methylene blue dye incorporated into AlMCM-41 can be reduced easily with respect to solution new methylene blue. New methylene blue interacting with surfactant polar heads and residual Br À ions as a results, it shows a couple of peaks in high potential with respect to new methylene blue solution. The electrode made with methylene blue-AlMCM-41 without surfactant was used for the mediated oxidation of ascorbic acid. The anodic peak current observed in cyclic voltammetry was linearly dependent on the ascorbic acid concentration. The calibration plot was linear over the ascorbic acid concentration range 1.0 Â 10 À5 to 5.0 Â 10 À4 M. The detection limit of the method is 1.0 Â 10 À5 M, low enough for trace ascorbic acid determination in various real samples.

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Room-temperature synthesis of silicate mesoporous MCM-41-type materials: influence of the synthesis pH on the porosity of the materials obtained

Cited by 119 publications

References 17 publications

Silica-based sulfonic acid (MCM-41-SO3H): a practical and efficient catalyst for the synthesis of highly substituted quinolines under solvent-free conditions at ambient temperature

Silica-based sulfonic acid (MCM-41-SO3H): a practical and efficient catalyst for the synthesis of highly substituted quinolines under solvent-free conditions at ambient temperature

Preparation of mesoporous silica (MCM41) and its use as an adsorbent for heavy metals for acid mine drainage

New Methylene Blue (NMB) Encapsulated in Mesoporous AlMCM‐41 Material and Its Application for Amperometric Determination of Ascorbic Acid in Real Samples

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