http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Aniruddha Ghosh,Bidyut Saha,Rumpa Saha 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.1
Oxidation of propanol by chromic acid produces propionaldehyde under kinetic condition [propa-nol]T≫ [Cr(VI)]T. This oxidation reaction is performed also in presence of micellar catalysts (anionic,cationic and neutral) and hetero-aromatic nitrogen bases promoters (picolinic acid, 2,20-bipyridine,1,10-phenanthroline) in aqueous media. The product is confirmed by 2,4-DNP test and 1H NMRspectroscopy. Anionic surfactant sodium dodecyl sulphate (SDS), neutral surfactant triton X-100 (TX-100) accelerated the reaction both in presence and absence of promoters whereas cationic surfactant Ncetylpyridinium chloride (CPC) inhibited the reaction. Combination of SDS and bipy is found to be themost efficient for this oxidation.
Ghosh, Sumanta K.,Saha, Rumpa,Ghosh, Aniruddha,Basu, Ankita,Mukherjee, Kakali,Saha, Indrajit,Saha, Bidyut Korean Chemical Society 2012 대한화학회지 Vol.56 No.6
Under pseudo-first order conditions, the monomeric species of Cr(VI) was found to be kinetically active in the absence of phenanthroline (phen) whereas in the phen-promoted path, the Cr(VI)-phen complex undergoes a nucleophilic attack by etane-1,2-diol to form a ternary complex which subsequently experience a redox decomposition leading to hydroxy ethanal and Cr(III)-phen complex. The effect of the cationic surfactant (CPC), anionic surfactant (SDS) and neutral surfactant (TX-100) on the unpromoted and phen-promoted path have been studied. Micellar effects have been explained by considering the preferential partitioning of reactants between the micellar and aqueous phase. Combination of TX-100 and phenanthroline will be the ideal for chromic acid oxidation of ethane-1,2-diol in aqueous media.
Ghosh, Aniruddha,Saha, Rumpa,Ghosh, Sumanta K.,Mukherjee, Kakali,Saha, Bidyut Korean Chemical Society 2013 대한화학회지 Vol.57 No.6
In the present investigation, kinetic studies of oxidation of formic acid with and without catalyst and promoter in aqueous acid media were studied under the pseudo-first order conditions [formic acid]T ${\gg}[Cr(VI)]_T$ at room temperature. In the 1,10-phenanthroline (phen) promoted path, the cationic Cr(VI) phen complex is the main active oxidant species undergoes a nucleophilic attack by the substrate to form a ternary complex which subsequently experiences a redox decomposition through several steps leading to the products $CO_2$ and $H_2$ along with the Cr(III) phen complex. The anionic surfactant (i.e., sodium dodecyl sulfate, SDS) and neutral surfactant (i.e., Triton X-100, TX-100) act as catalyst and the reaction undergo simultaneously in both aqueous and micellar phase with an enhanced rate of oxidation in the micellar phase. Whereas the cationic surfactant (i.e., N-cetyl pyridinium chloride, CPC) acts as an inhibitor restricts the reaction to aqueous phase. The observed net enhancement of rate effects has been explained by considering the hydrophobic and electrostatic interaction between the surfactants and reactants. The neutral surfactant TX-100 has been observed as the suitable micellar catalyst for the phen promoted chromic acid oxidation of formic acid.
Pintu Sar,Bidyut Saha,Aniruddha Ghosh,Susanta Malik,Dhiman Ray,Bijan Das 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.42 No.-
Oxidation of the three isomeric pentanols by potassium dichromate in aqueous acidic medium wasinvestigated spectrophotometrically at 25 C. The oxidation leads to the formation of correspondingcarbonyl products as identified by 1H NMR measurement and other techniques. The effects of cationic(cetylpyridinium chloride, CPCl), anionic (sodium dodecylsulphate, NaDS) and nonionic surfactant(polyoxyethylene octyl phenyl ether, TX-100) on reaction kinetics were studied. Moreover the catalyticeffect of surfactant in presence of three heteroaromatic nitrogen bases: 2-picolinic acid (2-PA), 2,20-bipyridyl (2,20-bipy) and 1,10-phenanthroline (1,10-phen) on the oxidation were also investigated. Thevalue of the rate constant in promoted and unpromoted reaction has been found to be higher in NaDSthan in TX-100 and CPCl micellar medium. Conductivity and tensiometry measurements were carried outto determine critical micellization concentration and free energy of micellization (DGm) of the usedsurfactant in presence of three pentanols. Among the different surfactant and promoter the combinationof 2,20-bipy and NaDS is efficient to exhibit1000 fold rate enhancement for oxidation of 1-pentanol andit is ‘selective’ over the rest of two pentanols oxidation.