IRANIAN JOURNAL OF CATALYSIS
Year:2014 | Volume:4 | Issue:1|Papers Count:9

A mild, efficient and fast method for the oxidation of alcohols and trimethylsilyl and tetrahydropyranyl ethers to their corresponding carbonyl compounds using CrO3 in the presence of sulfonic acid functionalized ordered nanoporous Na+- montmorillonite (SANM) and under solvent-free conditions is reported. All reactions were performed at room temperature in high to excellent yields. Ease of the preparation and handling of the catalyst, heterogeneous conditions, easy work-up of the products and high reaction rates are the main advantages of this method.

An efficient and green protocol for the synthesis of pyrazoles derivatives by one-pot reaction of different 1, 3-dicarbonyl compounds with hydrazines/hydrazides has been developed using nano-sulfated zirconia, nano-structured ZnO, nano-g-alumina and nano-ZSM-5 zeolites, as the catalyst. The optical properties of the nano-structured catalysts and organic molecules were studied. The advantages of methods are short reaction times and milder conditions, easy work-up and purification of products by non-chromatographic methods. The catalysts can be recovered for subsequent reactions and reused without any appreciable loss of efficiency.

The regioselective ring opening of styrene oxide using elemental iodine and bromine in the presence of disulfides as new catalysts was studied. The conductivity titration and UV spectroscopy were used to study the interaction of iodine with these catalysts. The results indicate that disulfide11 is efficient in polyiodide formation, and can catalyze this reaction in excellent yield and high regioselectivity. The complex [(11 -disulfide) I]+.I3- is considered to be formed initially which could be bulkier by addition of excess of iodine in the course of the reaction. These bulky nucleophiles have a fundamental role in the high regioselectivity by attacking the less sterically hindered epoxide carbon.

An efficient method has been developed for the catalysis of condensation of 1, 2-phenylenediamines and 2-aminothiophenoles with different aldehydes into their corresponding 2-aryl-1H-benzimidazoles and 2-aryl-1H-benzothiazoles under mild condition. In this method, trans-3, 5-dihydroperoxy-3, 5-dimethyl-1, 2-dioxolane (DHPDMDO) /HOAc/KI system was used as a novel and effective oxidant in water at room temperature with excellent results.

Nano-graphene oxide was synthesized by the oxidation of graphite powders. The structural nature of the nano-graphene oxide was characterized by a variety of techniques including XRD, TEM, FT-IR and UV/Vis. The functional groups on its basal planes and edges of nano-grahene oxide play important role in catalytic activity. The catalytic activity of nano-graphene oxide was investigated on Crossed-Aldol condensation reaction. This nanocatalyst was found to be highly efficient in this reaction and products were obtained in good to excellent yields. The recovered nanocatalyst was successfully reused for several runs without significant loss in its catalytic activity.

An efficient and convenient protocol for synthesis of 3-hydroxy-3-indolyl-2-oxindoles and 3, 3-diindolyl-2-oxindoles is presented here. The syntheses were achieved selectively under catalysis of LiClO4 whereby the products were obtained purely.

A green and convenient methode for the synthesis of a variety of xanthene derivatives by condensation reaction between aldehydes and b-naphthol or dimedone in an micellar solution of sodium dodecylphosphonate is described. This method offers several advantages, such as using of a cheap and environmentally benign reaction media, low loadings of sodium dodecylphosphonate as catalyst and easy work-up.

Easily synthesized1-methyl-3- (2-oxyethyl) -1H-imidazol-3-ium-borate sulfonic acid {[MOEI] -BSA} as a novel catalyst efficiently promoted the synthesis of quinoxaline derivatives via condensation of various diamines with 1, 2-dicarbonyl compounds at room temperature conditions in ethanol. This research provides a new method for the synthesis of quinoxalines in good to excellent yields with little catalyst loading. The catalyst could be recycled and reused several times without any loss of efficiency.

Introduction Crown ethers are heteroaromatic compounds that act as host compounds in Host-Guest chemistry, and can form complexes with organic or inorganic cations or anions. Among the crown ethers, 18- Crown-6 has the potential to form stable complexes with cations such as K+, and NO+. These reagents have nanotube-like structures, their X-ray are presented in the following. Their preparation methods are given.