Catalytic Method for Synthesis of Aspirin by a Green,Efficient and Recyclable Solid Acid Catalyst (Preyssler's Anion) at Room Temperature

Synthesis of aspirin at room temperature via O‐acetylation of salicylic acid in the presence of Preyssler type heteropolyacids has been investigated in order to contribute toward clean technology, which is the most important need of the society. All of the catalysts are recyclable and reusable.     

Acid induced reactions of a sydnone ketoxime

3-(2-Acetylphenyl)sydnone oxime 1a reacts with acids (methanesulfonic-, p-toluenesulfonic, trifluoroacetic-acid or Amberlite IR 118) to give products apparently derived from protonation of the oxime oxygen or nitrogen atom followed by cyclization to the sydnone ring or interception by water.     

Silver nanoparticles immobilized onto poly(4‐vinylpyridine)‐functionalized magnetic nanoparticles: A robust magnetically recyclable catalyst for oxidant‐free alcohol dehydrogenation

A heterogeneous and recyclable catalyst with a high loading of silver nanoparticles was synthesized via the silver nanoparticles being supported onto the surface of magnetic nanoparticles coated with poly(4‐vinylpyridine). The synthesized catalyst was used in the dehydrogenation of alcohols to corresponding carbonyl compounds. A broad diversity of alcohols was converted into their corresponding carbonyl compounds in excellent yields. The catalyst was easily recovered by applying an external magnetic field and reused for seven reaction cycles without considerable loss of activity. The catalyst was fully characterized using various techniques.     

Use of nanoporous Na+-montmorillonite sulfonic acid (SANM) as an eco-benign, efficient and reusable solid acid catalyst for the one-pot synthesis of 14-aryl-14-H-dibenzo[a,j]xanthenes and 1,8-dioxo-dodecahydroxanthene derivatives

Nanoporous Na⁺-montmorillonite sulfonic acid was found to be an efficient and green catalyst for the synthesis of various 14-aryl-14H-dibenzo[a,j]xanthenes and 1,8-dioxo-dodecahydroxanthene derivatives by the reaction of aldehydes with 2-naphthol and 1,3-cyclohexanedione, respectively. This novel synthetic method has the advantages of high yields, short reaction times and recyclability of the catalyst, simplicity and easy workup compared to the conventional methods reported in the literature.     

Laminar heat transfer and fluid flow of two various hybrid nanofluids in a helical double-pipe heat exchanger equipped with an innovative curved conical turbulator

Journal of Thermal Analysis and Calorimetry - In the present study, the effect of inserting an innovative curved turbulator and utilizing two types of hybrid nanofluids on thermal performance in a...     

AN EASY CONVERSION OF THE BAYLIS-HILLMAN ADDUCTS INTO tert-BUTYLDIMETHYLSILYL ETHERS WITH tert-BUTYLDIMETHYLSILYL CHLORIDE AND Li2S

The hydroxy group of the Baylis-Hillman adducts is protected with the t-butyldimethylsilyl (TBDMS) group using the reaction of adducts 1a–h with tert-butyldimethylsilyl chloride (TBDMSCl) in the presence of lithium sulfide under nearly acidic reaction conditions.     

One‐Step Synthesis of Aromatic Terminal Alkynes from Their Corresponding Ketones under Microwave Irradiation

One‐step microwave‐assisted synthesis of phenylacetylenes 2a–j from the corresponding ketones 1a–j in the presence of a new reagent, PCl₅–pyridine, is described. The reaction is carried out under a simple operational and experimental procedure, avoiding the use of the complicated and harsh multistep reaction.     

Facile and Efficient Method for the Synthesis of 14-Substituted-14-H-dibenzo[a,j]xanthenes Catalyzed by Ruthenium Chloride Hydrate as a Homogeneous Catalyst

Synthesis of dibenzoxanthenes through condensation of β-naphthol with various aromatic and aliphatic aldehydes in ethanol as an ecofriendly solvent using Ru^III as catalyst is reported.