Tetrazoles are an important class of heterocyclic compounds. A wide range of applications in pharmacological for preparation of drugs such antitumor, anti-inflammatory, antibacterial, anticonvulsant and anti-allergic and also in agriculture and plants as growth regulators, making explosives, and photography.
One of the most practical methods for the preparation of tetrazoles is [3+2] cycloaddition reaction between organic nitriles and sodium azide. Usually, this reaction is carried out more easily in the presence of Lewis or Brønsted acids. So far, a large number of catalysts such as NH4Cl, nano ZnO, Cu2O, TBAHS, and CuFe2O4 for the preparation of tetrazoles have been reported in literature.
In this project, it was decided to study the catalytic ability of nano silica boron sulfonic acid (NSBSA) as a heterogeneous nanocatalyst in the preparation of tetrazoles from nitriles and sodium azide.
To optimize the reaction conditions, initially, the reaction of benzonitile and sodium azide was selected as the reaction model.
Therefore, to develop a better catalytic system, various parameters such as the amount of catalyst, type of solvent, reaction temperature were investigated.
Nano silica boron sulfuric acid (NSBSA) is a dual brønsted/lewis acid. Recyclability, high surface area, easily separation from the reaction mixture as well as high efficiency are some of the advantages of nano silica boron sulfuric acid. According to SEM image and powder X-ray diffraction pattern (PXRD), NSBSA has average particle size of about 36 nm. Also EDX-Mapping Analysis of this catalyst showed a homogeneous distribution of S, O, Si atoms.
Different kinds of aliphatic of aromatic 5-substituted-1H-tetrazoles including electron-donating and electron-withdrawing groups were prepared in high yields and short reactions times in the presence NSBSA.

 Name: Parviz Surname: Movaheditabar

Title: Preparation of Tetrazoles from Nitrile Compounds using Nanosilica Melamine Trisulfonic Acid and CuO/aluminosilicate as Heterogeneous Catalysts
Supervisor: Dr. Mohammad Javaherian
Advisor: Dr. Valiollah Nobakht
Degree: Master of Science Major: Organic Chemistry
University: Shahid Chamran University of Ahvaz
Department: Chemistry Faculty: Sciences
Keywords: 5-Phenyl-1H-Tetrazoles, Nitrile Compounds, [3+‏2] Cycloaddition, Copper (II) Oxide/Aluminosilicate, NanoSilica Melamine Trisulfunic Acid, Ionic liquids.

Abstract :

Tetrazoles are important class of heterocyclic compounds. A wide range of applications in pharmacological for preparation of drugs such as cancer cells antiproliferative, antitumor, anti-inflammatory, antibacterial, anticonvulsant and anti allergic and also in agriculture and plants as oxidizers and growth regulators. Tetrazoles are also used in preparation explosives and photography. One of the most practical methods for the preparation of tetrazoles is [3+2] cycloaddition reaction between nitrile compounds and sodium azide. Usually, this reaction is carried out more easily in the presence of Lewis or Brønsted acids. So far, a large number of catalysts such as H₄N⁺Cl^-, nanoZnO, NaHSO₄.SiO₂, TBAHS, Cu-MCM-41, etc. for the preparation to tetrazoles have been reported in literature. In this project, it was decided to show the catalytic ability of nanosilica melamine trisulfonic acid (NSMTSA) and CuO/aluminosilicate as two heterogeneous nanocatalysts to be studied in preparation of tetrazoles from nitriles and sodium azide. Some Effective factors on the rate of rection such as amount of catalyst, type of solvent, reaction temperature were also investigated. According to SEM pictures and powder X-ray diffraction pattern (PXRD), the particle size of copper (II) oxide aluminosilicate was about 63 nm. Analysis PXRD show Spherical Morphology for the CuO/aluminosilicate nanoparticles. On the basis of EDX-Mapping Analysis, copper (II) oxide/aluminosilicate has a well distribution of copper particles in the context of aluminosilicate. Nanosilica Melamine Trisulfonic Acid (NSMTSA) is a heterogeneous solid acid with three site of acidic -SO₃H per a molecular. Recyclability easily separation from the reaction mixture as well as high efficiency are some of the advantage of using Nanosilica Melamine Trisulfonic Acid on the basis of SEM image and Analysis PXRD, NSMTSA has everage particle size of about 65 nm. Also EDX-Mapping Analysis shows a homogeneous distribution of C, N, O, Si, S atomes. Kinds of aromatic and aliphatic 5-substituted-1H-tetrazoles in this work different kinds of aromatic compounds including electron-donating and electron-withdrawing groups as well as short and long chain aliphatic 5-substituted-1H-tetrazoles rings were prepared in high yields and short reactions times of NSMTSA and CuO/aluminosilicate. Both nanocatalysts showed good efficiency in preparation and separation, reusability and high surface area and efficiency are some of the advantage of these nanocatalysts as reported in literature. some of the important derivatives of 5-substituted-1H-tetrazoles show So, encouraged by the results, we were also intercoted in perparating tosyl, mesyl and acyl derivatives of 5-substituted-1H-tetrazoles by seqvention one-pot procedure, under solvent free and it the presence of a suitable solvents. In addition, some of the dicationic and ionic liquids were synthesis by the reaction of the prepared of 5-substituted-1H-tetrazoles with and triethylene glycolditosylate under neat conditions.

 

 Esterification is one of the most fundamental reactions in organic chemistry. It has a great application in both laboratory work and industrial processes on account of its versatility. The esterification process consists of a reaction between a carboxylic acid and an alcohol in the presence of a acidic catalyst to obtain the corresponding esters. The ester products are mostly used as solvents, plasticizers, synthetic food odorants and scents, as well as precursors for various pharmaceuticals, agrochemicals and other compound. In recent years, the use of solid acids as heterogeneous catalysts has received tremendous interest in various areas of organic synthesis. Thus in this work nano silica based melamine trisulfonic acid (NSMTSA) catalyst was used as a heterogeneous solid acid catalyst and was prepared easily by chlorosulfonation of melamine as cheap and commercially available reagent, at ambient conditions. The prepared NSMTSA was successfully used for the esterification of a large number of carboxylic acids with a various kinds of alcohols under reflux conditions, in good to excellent yields.

 Synthesis of esters, especially cyclic esters (lactones), has great importance in polymer and ‎pharmaceutical industries. Baeyer-Villiger rearrangement, which involves synthesis of ester from ‎oxidation of ketones, has many advantages such as high stereoselectivity and chemoselectivity. In ‎this reaction, in the presence of any other functional group such as unsaturated bonds, only carbonyl ‎group is oxidized.‎
In this work, we wish to introduce the new applications of two solid acids; nano silica boron ‎sulfuric acid and nano zinc oxide in the presence of hydrogen peroxide as an oxidant in B-V ‎oxidation. Hydrogen peroxide is a mild, inexpensive and easily available oxidizing reagent which ‎produces the safest by-product; i.e water. Therefore, nano silica boron sulfuric acid as a dual ‎brønsted/lewis acid and also zinc oxide as efficient lewis acid were used to compensate weak ‎oxidizing character of hydrogen peroxide and also improving the electron-withdrawing property of ‎carbonyl group of ketones.‎
Oxidation of various of cyclic, acyclic and aromatic ketones to corresponding lactones and ‎esters was carried out using H₂O₂ (35%) and two nano catalysts; i.e nano silica boron sulfuric acid ‎and zinc oxide in 1-48 h and reflux in CHCl₃ with good to excellent yields and high selectivity. ‎

Water reducers, that are applied to produce the cement slurry with determine viscosity, are very important additive in drilling cement. Lignosulfonate is one of the most widely used of water reducers. Chemically, lignosulfonate is an organic anion which exist with various metallic counter ions such as sodium and potassium. In order to prepare lignosulfonate, the waste-water of paper mills, which called black liquor is used. Black liquor contains plenty of lignin. Lignin which is the most abundant bio-polymer after cellulose, is a raw material for production of lignosulfonate.
In this work the Chouka and Pars industrial waste water paper mills is used to prepare sodium lignosulfonate and potassium lignosulfonate. At First, lignin was separated from the black liquor by decreasing pH of the black liquor, then the prepared lignin was treated and refluxed with NaHSO3 and KHSO3 in an aqueous solution.
Finally the prepared lignosulfonates from waste-water of the above mentioned paper mills, decreased the water of the cement slurry up to 11.66-15%. In addition, these compounds improved the compressive strength of the drilling cement up to 1.3-1.5 times in compare to blank sample.