An efficient acidic functionalization of mesoporous silica LUS-1 (Laval University Silica) and its application as a recyclable heterogeneous catalyst in the synthesis of 2,4-diamino pyrimidine-5-carbonitriles via condensation reaction of aromatic aldehydes, malononitrile and guanidine carbonate in solvent-free condition has been reported. This green method offers a number of advantages such as short reaction time, good yields, simple work-up procedure, recyclable catalyst and environmentally friendly conditions.

An efficient and green synthesis is developed for the preparation of the arylidene isatinhydrazone derivatives 4a-m using a heterogeneous mesoporous acid catalyst of SBA-Pr-SO3H with a pore size of 6 nm under solvent free conditions. The hydrazones 4a-m were then analyzed by UV-Vis spectroscopy and the results were used for the calculation of the HOMO-LUMO band gap. In addition, the quantum chemical calculations were performed to provide an illustrative explanation for the obtained band gap; it is found that probably these molecules have a high tendency to donate electrons to the appropriate small-molecule acceptors with low energy and empty molecular orbital.

Sulfonic acid functionalized SBA-15 nanoporous material (SBA-Pr-SO3H) with a large pore size of 6 nm, a high surface area, high selectivity, and excellent chemical and thermal stability was applied as an efficient heterogeneous nanoporous acid catalyst in the reaction of isatin with pyrazolones under mild reaction conditions. A novel class of symmetrical spiro[indoline-3,4'-pyrano[2,3-c:6,5-c']dipyrazol]-2-one derivatives was successfully obtained in high yields. Comparison of these results with those reported in the literature shows that the current method is efficient, and results in better reaction times and yields of the desired products. Other advantages of this new method are its operational simplicity, easy work-up procedure, and the use of SBA-Pr-SO3H as a reusable and environmentally benign nanoreactor, such that the reaction proceeds easily in its nanopores. We also tested the antimicrobial activity of the prepared compounds using the disc diffusion method, and some of the synthesized compounds exhibited the best results against B. subtilis and S. aureus.

Sulfonic acid functionalized nanoporous silica (SBA-Pr-SO3H) with a pore size of 6 nm was synthesized using surface modification of Santa Barbara Amorphous (SBA-15). It is a solid acid hexagonally nano-reactor with high surface area and is reusable, high selective, non-corrosiveness which can easily isolate from the products. An efficient and green one-pot three component reaction was developed for the synthesis of pyrido[2,3-d]pyrimidine derivatives via a simple, mild and effective solvent free reaction of 4(6)-aminouracil, barbituric acid and aromatic aldehydes in the presence using SBA-Pr-SO3H. In this reaction, SBA-Pr-SO3H was an effective nano-catalyst which gave the products in good to high yields in a shorter reaction time compared to the other published reports. Some of the products were strong antibiotics against Bacillus subtilis and Staphylococcus aureus.

In this work, we report the Biginelli-type reaction between various aldehydes, acetophenones and urea systems in the presence of sulfonic acid functionalized silica (SBA-Pr-SO3H) under solvent-free conditions, which led to 4,6-diarylpyrimidin-2(1H)-ones derivatives. SBA-Pr-SO3H with a pore size of 6 nm was found to be an efficient heterogeneous solid acid catalyst for this reaction which led to high product yields, was environmentally benign with short reaction times and easy handling.

One-pot synthesis of benzo[c]acridine derivatives via the three-component condensation reaction of aromatic aldehydes, 1-naphtylamine, and dimedone using sulfonic acid functionalized SBA-15 (SBA-Pr-SO3H) as nanoporous acid catalyst under solvent-free conditions was studied. This reaction is an efficient, green and environmentally friendly procedure.

Se estudió la síntesis de derivados de benzo[c]acridina mediante la condensación de tres componentes en un solo paso, de aldehídos aromáticos, 1-naftilamina y dimedona, empleando como catalizador el ácido sulfónico SBA-15 (SBA-Pr-SO3H) en condiciones libres de disolvente. Esta reacción es un método eficiente, verde y amigable al medio ambiente.

Sulfonic acid functionalized SBA-15 (SBA-Pr-SO3H) with a pore size of 6 nm is an efficient catalyst in the green three-component condensation of phthalhydrazide, dimedone and aldehydes to give 2H-indazolo[1,2-b]plithalazine-triones under solvent-free conditions in excellent yields and short reaction times.

1,1-Diacetates are prepared in excellent yields from aldehydes and acetic anhydride under solvent-free conditions at room temperature in short reaction times using catalytic amount of sulfonic acid functionalized silica (SiO2-Pr-SO3H) which could be easily handled and removed from the mixture of reaction.

Chromium(III) at the ng L-1 level was extracted using partially silylated MCM-41 modified by a tetraazamacrocyclic compound (TAMC) and determined by inductively coupled plasma optical emision spectrometry (ICP OES). The extraction time and efficiency, pH and flow rate, type and minimum amount of stripping acid, and break- through volume were investigated. The method's enrichment factor and detection limit are 300 and 45.5 pg mL-1, respectively. The maximum capacity of the 10 mg of modified silylated MCM-41 was found to be 400.5±4.7 µg for Cr(III). The method was applied to the determination of Cr(III) and Cr(VI) in the wastewater of the chromium electroplating industry and in environmental and biological samples (black tea, hot and black pepper).