Octane number enhancement studies of naphtha over noble metal loaded zeolite catalysts

An Indian industrial naphtha containing mixture of various hydrocarbons belong to n-paraffins, isoparaffins, naphthenes and aromatics falling in C₅ to C₉ carbon range has been studied for its octane boosting through the production of isoparaffins over various Pt loaded zeolite catalysts possessing different acidity and porosity properties. Optimum balance of acid and metal functionalities in 0.6 wt.% Pt loaded on BEA zeolite helped in achieving highest increase in research octane number (RON) from 44 to 80, suitable for gasoline applications, through the production of lower isoparaffins (iC₄-iC₆) along with C₇+ isoparaffins.     

(R/S)‐BINOL‐α‐Phosphoryloxy Enecarbamate‐Mediated and (R/S)‐Titanium(IV) BINOLates‐Catalyzed Enantioselective Intramolecular Heck/Aza‐Diels–Alder Cycloaddition (IHADA): An Expedient Methodology

An (R/S)‐titanium(IV) BINOLate‐catalyzed highly enantioselective intramolecular Heck/aza‐Diels–Alder cycloaddition (IHADA) cascade was developed to prepare tetrahydropyridoindoles (tHPs) and octahydropyrazinopyridoindoles (oHPPs) from in situ generated (R/S)‐BINOL α‐phosphoryloxy carbamate ( αPPC2 ) in one pot. Chiral cooperativity between (R/S)‐αPPC2 and (R/S)‐titanium(IV) BINOLate was observed and successfully utilized for the construction of various tHPs (7 examples) and oHPPs (17 examples).

     

Studies of spinodal decomposition in a ternary polymer‐solvent‐nonsolvent system

Much of the work in modeling and computer simulation of spinodal decomposition has been done for binary systems. This work attempts to carry out the analysis of spinodal decomposition in ternary polymer‐solvent‐nonsolvent systems, where the solvent is the monomer used to produce the polymer and the nonsolvent is the major component. Various experimental methods are used to determine values of the parameters of the ternary version of the Cahn‐Hilliard equation of spinodal decomposition, such as cloudpoint experiments, time‐resolved light scattering in the ternary system, and morphological development of polymer membranes formed during the early stages spinodal decomposition. The combination of these experimental methods and computer simulation work shows the validity of the assumptions made in characterizing spinodal decomposition in ternary polymer systems of interest.     

Cyclic voltammetric study of zinc and zinc oxide electrodes in 5.3 M KOH

The behaviour of zinc and zinc oxide in 5.3 M KOH in the presence of alkaline earth oxides, SnO, Ni(OH)₂ and Co(OH)₂ was examined by cyclic voltammetry. The influence of the alkaline earth oxides was compared with additives of established effects (Bi₂O₃, LiOH, Na₂CO₃ and CdO). The alkaline earth oxide each exhibits a distinct behaviour towards zincate. Whereas, a single process of interaction with zincate was shown by CaO; two modes of reaction were obtained with SrO and BaO. Solid solution formation was noticed with BeO and MgO. The other additives forming solid solution with ZnO were CdO, SnO. The ionic sizes of Ni(OH)₂ and Co(OH)₂ allow solid solution formation with Zn(OH)₂. Both Bi₂O₃ and Na₂CO₃ enter into complexation with zincate. LiOH forms two distinct zincates, of which one is an oxo zincate leaching the `hydroxyl' functionality. Cyclic voltammetry revealed the deposition of the oxide/hydroxide additives as metal prior to the onset of zinc deposition and the potential range for this additive metal deposition is almost the same for different additives (SnO, CdO, Ni(OH)₂). The beneficial action of these additives to zinc alkaline cells is associated with a substrate effect. The implication of this electrocatalytic deposition of metals on a zinc oxide electrode is also discussed.     

Improved transfection efficiency of chitosan‐DNA complexes employing reverse transfection

The present study was designed to systematically compare the conventional and reverse transfection methodologies for chitosan/DNA complexes using a low molecular weight (MW) chitosan. The hydrodynamic diameter of the complexes, measured by Dynamic Light Scattering (DLS) was found to be ～ 216 nm and TEM investigations showed spherical and compact complexes with an average size of 200 nm. The transfection efficiency of chitosan using the two methodologies was assessed by employing reporter gene coding for green fluorescent protein (GFP) and luciferase. More than 50% of HEK 293 cells were transfected when transfection done using reverse transfection strategy at pH 6.5 with 10% serum for 24 h followed by media replenishment with pH 7.4 with 10% serum for an additional 24 h period. Also, the cytotoxicity of chitosan/DNA complexes was also considerably lower than the commercially available transfection reagent lipofectamine. Our investigation concludes that maximal transgene expression levels could be achieved using reverse transfection where the chitosan/DNA complexes are pre‐incubated on the plate surface followed by plating of cells at pH 6.5 with 10% serum for 24h and media resupplemented with pH 7.4 with 10% serum for an additional 24 h period. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Solution Structure and Dynamics of the Small Protein HVO_2922 from Haloferax volcanii

Past sequencing campaigns overlooked small proteins as they seemed to be irrelevant due to their small size. However, their occurrence is widespread, and there is growing evidence that these small proteins are in fact functionally very important in organisms found in all kingdoms of life. Within a global proteome analysis for small proteins of the archaeal model organism Haloferax volcanii, the HVO_2922 protein has been identified. It is differentially expressed in response to changes in iron and salt concentrations, thus suggesting that its expression is stress-regulated. The protein is conserved among Haloarchaea and contains an uncharacterized domain of unknown function (DUF1508, UPF0339 family protein). We elucidated the NMR solution structure, which shows that the isolated protein forms a symmetrical dimer. The dimerization is found to be concentration-dependent and essential for protein stability and most likely for its functionality, as mutagenesis at the dimer interface leads to a decrease in stability and protein aggregation.     

Hydrogen peroxide sensing properties of PVA/TiO2/I2 nanocomposite‐based free standing membranes

The nanocomposite of titanium‐di‐oxide (TiO₂)/iodine (I₂) in polyvinyl alcohol (PVA) matrix has been explored to be used in hydrogen peroxide (H₂O₂) sensing applications for the first time. The proposed nanocomposite can be easily casted in the form of thin film on glass substrates as well as free standing membranes. These nanocomposite films and membranes exhibit reduced resistance values and easily observable colour changes in the presence of H₂O₂. The films also exhibit significant quenching in photoluminescence emission properties upon H₂O₂ exposure. These sensor responses have been attributed to redox reactions at nanocomposite films and H₂O₂ interface. This study indicates an easy to fabricate, flexible and environmental friendly sensing platform for H₂O₂. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42257.     

Isothermal crystallization kinetics of polypropylene in melt‐mixed composites of polypropylene and multi‐walled carbon nanotubes

The isothermal crystallization behaviour of the polypropylene (PP) phase in PP/multi‐walled carbon nanotubes (MWCNTs) composites has been investigated via differential scanning calorimetric analysis, which showed the influence of the varying dispersion level of MWCNTs in the respective PP matrix. PP/MWCNTs composites were prepared via melt‐blending technique, wherein two different grades of MWCNTs of varying average “agglomerate” size and varying entanglements (N‐MWCNTs and D‐MWCNTs) were utilized. Furthermore, the influence of melt‐viscosity of the PP phase was investigated on the crystallization kinetics of the PP/MWCNTs composites. Heterogeneous nucleation ability of MWCNTs has resulted in a decrease in half time of crystallization (t _1/2) from ～14 min for pure PP to ～6 min for PP/N‐MWCNTs and ～11 min for PP/D‐MWCNTs composites at 1 wt% of MWCNTs at 132 °C. Overall rate of crystallization (k) has significantly increased to 4.9 × 10^?2 min^?1 for PP/N‐MWCNTs composite as compared with 6.2 × 10^?3 min^?1 for PP/D‐MWCNTs composite at 0.5 wt% of MWCNTs at 132 °C. Moreover, the effect of a novel organic modifier, Li‐salt of 6‐amino hexanoic acid along with a compatibilizer (PP‐g‐MA) has also been investigated on the crystallization kinetics of the PP phase in PP/MWCNTs composites. POLYM. ENG. SCI., 57:1136–1146, 2017. © 2017 Society of Plastics Engineers     

Comparative study of allelopathy as exhibited byProsopis Juliflora swartz andProsopis cineraria (L) druce

The allelopathic effects ofProsopis juliflora were studied both in the laboratory and in nature and compared with that ofProsopis cineraria to understand the chemical nature of allelochemics. Both species occupy the same habitats butP. cineraria does not appear to have any toxic effect on other plants under its canopy.P. juliflora is highly allelopathic and does not allow the growth of any other species. Leaf extracts and leaf leachates ofP. juliflora were inhibitory. Decaying leaves were also inhibitory at early stages of decomposition. Live roots were not found to be inhibitory in cogermination and interplanting of seeds. Chemical investigation of the extracts showed the allelopathic compounds to be phenolic in nature in both the species. Slow decomposition and heavy accumulation of leaf litter belowP. juliflora may possibly result in accumulation of toxic substances in soil layers, inhibiting growth of other species.