Articles written in Journal of Chemical Sciences
Volume 125 Issue 5 September 2013 pp 1185-1195
Synthesis, characterization and catalytic activity of sulphonated multi-walled carbon nanotubes as heterogeneous, robust and reusable catalysts for the synthesis of bisphenolic antioxidants under solvent-free conditions
In this study, a simple and green method has been developed for the synthesis of bisphenolic antioxidants by the reaction of 2-
Volume 128 Issue 8 August 2016 pp 1277-1284 Regular Article
Two highly acidic, imidazolium-based, functionalized dicationic ionic liquids (FDCILs) were synthesized and characterized by FTIR, ¹H NMR and¹³ C NMR. The synthesized FDCILs were used as efficient and green catalysts in the synthesis of phthalate plasticizers through esterification of phthalic anhydride (PhA)with ethanol, n-propanol and n-butanol. Among these two FDCILs, (dimethyl-4-sulfobutyl-ammonium) 1,2- ethan-1-methyl-imidazolium-sulfonic acid hydrogen sulfate performed better. The catalytic activity of FDCIL is related to the density of acidic groups on it and the length of the carbon chain in the cationic part. Theinfluences of the reaction temperature, catalyst dosage, and molar ratio of phthalic anhydride to alcohol on the esterification reaction were investigated. The reusability of the catalyst in these reactions was studied too. Theb diester phthalates were obtained up to 98.8% yield. The products can be separated easily by decantation from the reaction mixture.
Volume 130 Issue 5 May 2018 Article ID 0048
In this study, two novel acidic ionic liquids, including a hydroxyl functionalized diacidic ionic liquid [HFDAIL] and a sulfonated diacidic ionic liquid [SFDAIL], were prepared and immobilized on the surface of silica nanoparticles (SNPs) via hydrogen bonding. The materials were characterized by FT-IR, NMR, SEM, nitrogen physisorption measurement, TGA and acid-base titration. The catalytic activity of the prepared catalysts was investigated in the synthesis of phthalate, maleate and succinate diesters under solventfree conditions. It was found that nanosilica@[HFDAIL] with higher availability of acidic sites and higher hydrophilicity was more efficient compared to the nanosilica@[SFDAIL]. Notably, nanosilica@[HFDAIL] catalyst has also demonstrated excellent selectivity for the diester product while the monoester product was predominant in the case of nanosilica@[SFDAIL] even after prolonged reaction time or higher catalyst loading.In addition, the nanosilica@[HFDAIL] catalyst could be separated by simple filtration and reused several times without any significant loss of catalytic performance, but a remarkable decrease in activity was observed fornanosilica@[SFDAIL] in the next runs.
Volume 132 All articles Published: 25 September 2020 Article ID 0134
Ketamine [2-(2-chlorophenyl)-2-methylamino-cyclohexan-1-one] has been used in both veterinary and human medicine. In this research, a new and efficient protocol has been developed for the synthesis of ketamine, by using hydroxy ketone intermediate. Synthesis of this drug has been done in five steps. At first,the cyclohexanone was made to react with 2-chlorophenyl magnesium bromide reagent followed by dehydration in the presence of an acidic ionic liquid, 1-methyl-3-[2-(dimethyl-4-sulfobutyl-ammonium) ethane] imidazolium hydrogen sulfate to obtain 1-(2-chlorophenyl)-cyclohexene. The oxidation of the synthesized alkene by potassium permanganate gave corresponding hydroxy ketone intermediate. The imination of this intermediate by methyl amine and finally the rearrangement of the obtained imine at elevated temperatureresulted in the synthesis of ketamine. All of the intermediates and the product were characterized by 1H-NMR and IR spectroscopies. No need to use toxic bromine (which is used in most of the reported procedures for thesynthesis of ketamine), high reaction yields and use of commercially available and safe materials and no need to use corrosive acids in the dehydration step are some of the advantages of this procedure over the common reported ones for the snthesis of ketamine
Volume 133 All articles Published: 11 August 2021 Article ID 0086
In this study, a new class of energetic phthalate plasticizers based on imidazolium ionic liquids(ILs) were synthesized. The structure of the synthesized compounds was confirmed by 1HNMR, 13CNMR,and FT-IR. The thermal stability of nitrocellulose (NC)/plasticizer blends was also evaluated by thermogravimetricanalysis (TGA). The compatibility of the NC with three synthesized energetic plasticizers wasstudied by differential scanning calorimetry (DSC), scanning electron microscope (SEM), and densityfunctional theory (DFT) methods. The glass transition temperatures of the NC/synthesized plasticizer blendswere determined by DSC and showed desirable lowering of glass transition temperature with a single peakand low temperature, which indicates the compatibility of NC with the synthesized IL plasticizers. The SEMimages of plasticized films show smooth surfaces which are resulted from the good compatibility of theplasticizers with NC. The predicted relative trend of interaction energies between NC and plasticizers is wellcorrelated with the corresponding trend of Tg of NC/plasticizer blend. In addition, molecular electrostaticpotential (MEP) calculations were performed for all plasticizers/NC. Total electron density for the DEP/NC,3a/NC, 3b/NC and 3c/NC samples are respectively 0.0388, 0.0942, 0.0944 and 0.0823. There is a very goodregression (R2 = 0.9126) between these values and the calculated values of the interactions energy.
In this study, a new class of energetic phthalate plasticizers based on imidazolium ionic liquids were synthesized. The compatibility of NC with these energetic plasticizers was studied by differential scanning calorimetry (DSC) and density functional theory (DFT) methods.
Volume 133, 2021
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