Search results for "Heptane"
showing 10 items of 103 documents
Calorimetric investigation on the formation of palladium nanoparticles in water/AOT/n-heptane microemulsions
1995
The formation enthalpy of palladium nanoparticles in water/sodium bis(2-ethylhexyl) sulfosuccinate (AOT)n-heptane microemulsions as a function of the waterAOT molar ratio (R = [water][AOT]) was measured by a calorimetric technique. The results indicate that at R < 10 the energetic state of the palladium nanoparticles compartmentalized within the reversed AOT micelles is signficantly different from that in bulk water. Effects due to the small size of the palladium nanoparticles and to interactions between nanoparticles and the waterAOT interface are discussed.
Catalytic activity of large-pore high Si/Al zeolites: Cracking of heptane on H-Beta and dealuminated HY zeolites
1987
Abstract The catalytic activity, selectivity, catalyst decay, thermal and hydrothermal stability, and acidity of H-Beta and HY zeolites with Si Al ratios of 7.5 and 10, respectively, have been studied during cracking of n-heptane at 450 °C and atmospheric pressure. It has been found that the H-Beta zeolite is more active and decays more slowly than HY. H-Beta presents a higher steric hindrance for dibranched molecules and therefore its open structure should be smaller than that of HY. A lower hydrogen transfer activity and hydrothermal stability is observed for H-Beta in comparison with the corresponding HY.
Hydrocracking ofn-heptane with a NiO-MoO3/HYUS zeolite as catalyst. Kinetic study
1988
The hydrocracking of n-heptane has been carried out in a fixed bed reactor at 2.45 MPa pressure and with a H2/n-heptane molar ratio of 5.0 using a 4 wt% NiO - 8 wt% MO3/HYUS zeolite as a catalyst. The W/F10 ratio was varied between 75.3 and 1624 kg · s/kmol at different reaction temperatures: 573, 588, 603 and 623 K. The kinetics of the reaction has been studied by two different procedures due to the slight deactivation of the catalyst. One of them uses the conversion and yield values extrapolated at time on stream to zero and the other uses a kinetic equation where the deactivation of the catalyst has been included. The experimental data were fit well by a pseudo-first order kinetic equati…
A new potential toxaphene congener: synthesis, GC/EI-MS study, crystal structure, NMR analysis, and ab initio calculations of 3-endo,5-endo-dichloro-…
2001
Abstract A new potential toxaphene congener 3- endo ,5- endo -dichloro-7,7-bis-chloromethyl-4-dichloromethyl-tricyclo[2.2.1.0 2,6 ]heptane 2 has been isolated from reaction mixture obtained by the chlorination of 2- exo ,10,10-trichlorobornane 1 . The X-ray structural analysis of 2 revealed an unusual tricyclic structure, where the two chlorine atoms occupying endo -positions are in close spatial proximity with each other and near to the neighbouring CHCl 2 group. Further, it revealed that the symmetry of the molecule is distorted. The 1 H and 13 C NMR spectra of 2 have been assigned by means of 1 H, 1 H d ouble- q uantum f iltered co rrelation s pectroscop y (DQF COSY), PFG 1 H, 13 C HMQC …
Determination and separation of diarylheptanoids from alder growing in Latvia
2015
The composition of diarylhepatnoids fraction isolated from bark of two alder species (grey alder and black alder) was studied. The efficiency of three extraction methods used for isolation of diarylhepatnoids from alder bark was compared. Two diarylhepatnoids: 1,7-bis-(3,4-dihydroxyphenyl)-heptan- 3-one-5-O-β-D-xylopyronoside (oregonin) and 1,7-bis-(3,4-dihydroxyphenyl)-3-hydroxyheptane-5-O-β-D- xylopyranoside were isolated from the bark of grey alder. The phenolic components of the extracts were analyzed by high-performance liquid chromatography (HPLC). Quantitative determination of oregonin was performed using an internal standard method. The results obtained show that alder barks are ric…
CCDC 882133: Experimental Crystal Structure Determination
2012
Related Article: M.V.Leskinen, Kai-Tai Yip, A.Valkonen, P.M.Pihko|2012|J.Am.Chem.Soc.|134|5750|doi:10.1021/ja300684r
Inverse solvent effects in the heterogeneous and homogeneous epoxidation of cis-2-heptene with [2-percarboxyethyl]-functionalized silica and meta-chl…
2014
The rate constants for the epoxidation of cis-2-heptene with [2-percarboxyethyl]-functionalized silica (1a) and meta-chloroperbenzoic acid (mCPBA) (1b) in different solvents have been determined at temperatures in the −10 to 40 °C range. The heterogeneous epoxidation exhibits a dependence of the reaction rate on solvent polarity opposite to its homogeneous counterpart and anomalous activation parameters in n-hexane, which are interpreted in terms of the surface-promoted solvent structure at the solid–liquid interface. The results show that highly polar solvents can strongly inhibit heterogeneous reactions performed with silica-supported reagents or catalysts.
A Bioinspired Approach to Tri-nor-guaianes. Synthesis of (−)-Clavukerin A
2006
A bioinspired approach to tri-nor-guaianes by degradation of the C-7 side chain of related guaia-11-enes is described. In this approach (-)-clavukerin A (1) is obtained by selective ozonolysis-Criegge rearrangement of (+)-1alphaH,7alphaH,10alphaH-guaia-4,11-dien-3-one (4) to afford 7beta-hydroxy and 7beta-acetoxy tri-nor-guaiane derivatives 6 and 7, respectively, which after elimination and deoxygenation give the title compound. The starting guaiadienone is readily obtained from commercially available santonin or (+)-dihydrocarvone.
Microwave radiation effect on the synthesis of cadmium sulphide nanoparticles in water in oil microemulsion: a preliminary study at different frequen…
2004
AbstractCadmium sulphide nanoparticles have been synthesised in water/sodium bis (2-ethylhexyl) sulfosuccinate (AOT)/n- heptane microemulsions kept at 30 °C by microwave irradiation coupled with water-cooling and in conventional thermostatic conditions at the same temperature. The study has been performed exposing the reaction media to microwave radiation at five different frequencies (2.45, 2.85, 8, 12 and 18 GHz). For each frequency, a suitable microwave exposure set-up has been assembled. During the growth process, the dimensions of the nanoparticles have been characterised by means of UV-Vis spectroscopy. At the end of the growth process, the surface morphology of the nanoparticles has …
Structural Variation and Magneto-Structural Correlation in Two New Dinuclear Bis(µ2-Phenoxo)-Bridged CuII Schiff-Base Complexes: Catalytic Potential …
2010
Two new dinuclear bis(μ2-phenoxo)-bridged copper(ii) complexes [Cu(NCS)L1]2 (1) and [Cu(NCS)L2]2 (2) have been synthesized using two tridentate NNO-donor Schiff-base ligands, L1H (Me2N(CH2)3N=CHC6H3(OMe)(OH)) and L2H (Me2N(CH2)3N=C(CH3)C6H4(OH)), respectively. They have been characterized by elemental analyses, IR, UV-visible, and electron paramagnetic resonance (EPR) spectroscopy, cyclic voltammetry, and magnetic susceptibility measurements. X-Ray single-crystal structures reveal a central Cu2O2 core in each complex with an isothiocyanate ligand coordinated terminally to each metal centre. The coordination environments around the CuII ions in 1 and 2 are a distorted trigonal bipyramid and…