Search results for "Hexane"
showing 10 items of 467 documents
The effect of THF and the chelating modifier DTHFP on the copolymerisation of β-myrcene and styrene: kinetics, microstructures, morphologies, and mec…
2022
The statistical anionic copolymerisation of the biobased monomer β-myrcene with styrene in cyclohexane was investigated via in situ near-infrared (NIR) spectroscopy, focusing on the influence of the modifiers (i.e., Lewis bases) tetrahydrofuran (THF) and 2,2-di(2-tetrahydrofuryl)propane (DTHFP) on the reactivity ratios. With increasing [modifier]/[Li] ratio, the reactivity ratios in the system myrcene/styrene are adjustable from rS ≪ rMyrvia rS ≈ rMyr to rS ≫ rMyr. The bidentate modifier DTHFP affects the reactivity ratios much more than THF: minute amounts only (0.35 equivalent relative to Li) are required to randomize the copolymer, and one equivalent to invert the reactivity ratios. Usin…
Pressure dependence of the demixing of polymer solutions determined by viscometry
1981
From the break-down in the viscosity of a polymer solution, associated with the entrance into the two phase region, the pressure dependence of the demixing temperatures of solutions of polystyrene (M = 600.000) in cyclohexane, cyclopentane, diethylmalonate and 1-phenyldecane was measured up to 1000 bar. The application of pressure increases the solubility of polystyrene in cyclopentane and diethylmalonate, but decreases that in 1-phenyldecane; in the case of cyclohexane, a pressure of optimum miscibility is observed at ca. 120 bar.
Catalytic oxidation of n-hexane promoted by Ce1-xCuxO2 catalysts prepared by one-step polymeric precursor method
2013
Abstract Ceria-supported copper catalysts (Ce1−xCuxO2, with x (mol) = 0, 0.01, 0.03, 0.05 and 0.10) were prepared in one step through the polymeric precursor method. The textural properties of the catalysts were investigated by X-ray diffraction (XRD), Rietveld refinement, N2-physisorption (BET surface area), electron paramagnetic resonance (EPR), UV–visible diffuse reflectance and photoluminescence spectroscopies and temperature-programmed reduction (TPR). In a previous study ceria-supported copper catalysts were found to be efficient in the preferential oxidation of CO. In this study, we extended the catalytic application of Ce1−xCuxO2 systems to n-hexane oxidation and it was verified tha…
Dipotassium 4,4'-(hexane-3,4-di-yl)bis-(benzene-sulfonate) dihydrate.
2008
The anion of the title compound, also called sygethin dihydrate, 2K(+)·C(18)H(20)O(6)S(2) (2-)·2H(2)O, has crystallographic inversion symmetry. The K(+) cation is surrounded by eight O atoms in a distorted cubic coordination geometry, forming extended K-O-S networks. There are also O-H⋯O hydrogen bonds.
Bis(cyclohexylammonium) tetrachlorido(oxalato)stannate(IV)
2013
The title salt, (C6H14N)2[Sn(C2O4)Cl4], was obtained as a by-product from the reaction between 2C6H14N+·C2O42−·1.5H2O and SnCl2·2H2O. The cyclohexylammonium cation has a chair conformation. The complex anion consists of an oxalate anion chelating the SnCl4 moiety, resulting in a distorted octahedral coordination sphere of the SnIV atom with the O atoms in equatorial cis positions. In the crystal, cations and anions are linked through N—H...O and N—H...Cl interactions into a layered arrangement parallel to (100).
Darstellung und struktur von (EtO)2P(O)CH2Si(Me)2CH2SnMe2Cl—ein sechsringchelat mit sesselkonformation und PO ⋯ Sn(Cl)Me2CH2-trigonaler bipyramide a…
1992
Abstract The title compound (EtO)2P(O)CH2Si(Me)2CH2SnMe2Cl (2) has been synthesized by reaction of the new functional Grignard reagent (EtO)2P(O)CH2CH2SiMe2CH2MgCl with Me3SnCl and subsequent treatment with Me2SnCl2. 2 crystallizes in the non-centrosymmetric orthorhombic space group P212121. The structure was refined to a final R-value of 0.0476. The tin atom is pentacoordinated and exhibits a nearly ideal trigonal-bipyramidal coordination (SnCl 2.518(3), Sn ⋯ O 2.371(5) A). This coordination results from a 6-membered chelate involving a chair conformation. The structure of 2 is compared with analogous compounds containing a PO ⋯ Sn- or CO ⋯ Sn-coordination in the first place and a noncy…
Ferromagnetic Cu(II)4, Co(II)4, and Ni(II)6 azido complexes derived from metal-assisted methanolysis of di-2,6-(2-pyridylcarbonyl)pyridine.
2009
Reaction of copper(II) perchlorate with di-2,6-(2-pyridylcarbonyl)pyridine (pyCOpyCOpy, dpcp) in the presence of sodium azide yields complex [Cu(4)(N(3))(2){pyC(OMe)(O)pyC(OMe)(O)py}(2)(MeOH)(2)](ClO(4)) x 2 MeOH (1 x 2 MeOH), which crystallizes in the monoclinic P2(1)/c space group. Similar reaction of cobalt(II) nitrate yields complex [Co(4)(N(3))(2)(NO(3))(2){pyC(OMe)(O)pyC(OMe)(O)py}(2)] x 0.5 MeOH (2 x 0.5 MeOH) which crystallizes in the monoclinic I2/m space group. Reaction of nickel(II) perchlorate yields complex [Ni(6)(CO(3))(N(3))(6){pyCOpyC(O)(OMe)py}(3)(MeOH)(2)(H(2)O)][Ni(6)(CO(3))(N(3))(6){pyCOpyC(O)(OMe)py}(3) (MeOH)(3)](ClO(4))(2) x 1.8 MeOH (3 x 1.8 MeOH), which crystallizes…
Simple chiral urea gelators, (R)- and (S)-2-heptylurea: their gelling ability enhanced by chirality.
2011
Abstract We present the first report on the synthesis of chiral ureas, ( R )- and ( S )-2-heptylurea, and their gelling behaviors. The ureas were prepared by the reactions of chiral amines and phenyl carbamate in the presence of triethylamine. On cooling from homogeneous solutions, the chiral ureas form gels in water and various nonpolar organic solvents, such as cyclohexane, toluene, and tetrachloromethane, while the racemate gelatinize only toluene and tetrachloromethane among the solvents we examined. The gelling ability of the enantiomeric urea is higher than the racemate, as the critical gelling concentrations in toluene, for example, were 0.2% and 0.7% (wt/wt), respectively. The enhan…
Crystal structure of lactitol (4-O-beta-D-galactopyranosyl-D-glucitol).
1992
Abstract Lacitol, C 12 H 24 O 11 , is monoclinic, space group P 2 1 with cell dimensions a = 7.614(1), b = 10.757(1), c = 9.370(1) A, β = 108.19(1)°, and V = 729.0(1) A 3 ; Z = 2, D x = 1.57 Mg.m −3 , λ(Cu- K α ) = 1.5406 A, μ = 1.166 mm −1 , F (000) = 368, and T = 23°. The structure was solved by direct methods and refined by least-squares calculations to R = 0.048 for 1510 unique observed reflections. There are one intra- and eight inter-molecular hydrogen bonds in the structure. Bond lengths and angles accord well with the mean values of related structures. The galactopyranosyl ring has a chair conformation.
Polymorphism control of an active pharmaceutical ingredient beneath calixarene-based Langmuir monolayers.
2014
This communication demonstrates the possibility to nucleate and grow different crystalline polymorphic forms of gabapentin (GBP) using, as nucleation templates, Langmuir monolayers of an amphiphilic calixarene at different packing densities.