Determination of the Henry’s Law Constant of Hexane in High-Viscosity Polymer Systems

The Henry’s law constant of volatiles in polymer systems is a crucial parameter reflecting the gas-liquid equilibrium,which is very important for devolatilization.In this research,polyolefin elastomer(POE)-cyclohexane and polydimethylsiloxane(PDMS)-hexane systems were studied,and the Henry’s law constant was obtained by measuring the gas phase equilibrium partial pressure when polymer solutions containing different mass fractions of volatiles reached a saturated state.The effects of temperature,type of volatiles,and polymer viscosity on the gas phase equilibrium partial pressure and Henry’s law constant of the volatiles were investigated.The results indicate that,with the increase of temperature and polymer viscosity,the gas phase equilibrium partial pressure and Henry’s law constant of volatiles increase.As temperature increases,the solubility of gas in liquid decreases.The relationship between the Henry’s law constant and temperature is consistent with the Arrhenius law.In the PDMS-hexane system,the gas phase equilibrium partial pressure and Henry’s law constant of n-hexane are higher than those of cyclohexane.The obtained Henry’s law constants can be used as a reference for perfecting the devolatilization process and improving the devolatilization effect.

Larvicidal and irritant activities of hexane leaf extracts of Citrus sinensis against dengue vector Aedes aegypti L.

Objective:To assess the larvicidal and irritant activities of the hexane extracts of leaves of Citrus sinensis(C.sinensis)against the early fourth instars and female adults of Aedes aegypti(Ae.aegypti).Methods:The larvicidal potential of the prepared leaf extract was evaluated against early fourth instar larvae of Ae.aegypli using WHO protocol.The mortality counts were made after 24 h and LC_(50)and LG_(50)values were calculated.The efficacy of extract as mosquito irritant was assessed by contact irritancy assays.Extract-impregnated paper was placed on a glass plate over which a perspex funnel with a hole on the top was kept inverted.Single female adult,3-day old unfed/blood-fed,was released inside the funnel.After 3 min of acclimatization time,the time taken for the first take-off and total number of flights undertaken during 15 min were scored.Results:The citrus leaf extracts from hexane possessed moderate larvicidal efficiency against dengue vector.The bioassays resulted in an LC_(50)and LC_(90)value of 446.84 and 1370.96 ppm,respectively after 24 h of exposure.However,the extracts were proved to be remarkable irritant against adults Ae.aegypti,more pronounced effects being observed on blood-fed females than unfed females.The extract-impregnated paper was thus proved to be 7-11 times more irritable as compared with the control paper.Conclusions:The hexane extracts from C.sinensis leaves are proved to be reasonably larvicidal But remarkably irritant against dengue vector.Further studies are needed to identify the possible role of extract as adulticide,oviposition deterrent and ovicidal agent.The isolation of active ingredient from the extract could help in formulating strategies for mosquito control.

Multilayer Graphene Synthesized by CVD Using Liquid Hexane as the Carbon Precursor

We produce multilayer graphene by the Chemical Vapor Deposition (CVD) method at atmospheric pressure and 1000°C, using flexible copper substrates as catalyst and liquid hexane as the source of carbon. We designed an optical device to measure the transmittance of the carbon films;with this information we calculate that the approximate number of layers is 11.

Effect of Rare Earths on n-Hexane Aromatization over HZSM-5 Catalyst

The cracking and aromatization of n hexane over H ZSM 5 modified by various rare earths were investigated by means of continuous flow micro reactor. The surface properties of modified H ZSM 5 catalysts were obtained from IR, XRD and XPS. The results show that the rare earths enhance the aromatizing properties of the catalysts which are prepared by mechanical mixture method. The results of n hexane cracking and aromatization are correlated with the acidity. The Brnsted acidic sites are the active sites of n hexane aromatization, while Lewis acid site plays an important role in n hexane cracking.

Separation of hexane isomers by introducing“triangular-like and quadrilateral-like channels”in a bcu-type metal-organic framework

The separation of hexane isomers is of vital importance to produce high quality gasoline in the petrochemical industry.However,the similar vapor pressure and boiling point of hexane isomers bring great difficulties and challenges in the separation process.Sieving effect,which allowing smaller molecules pass through and preventing others,should be a powerful strategy to solve this problem by making good use of porous materials.Therefore,physical separation by metal-organic framework(MOF)materials appears and becomes a burgeoning separation technique in industry.Due to the weak interaction between hexane isomers with absorbents,it puts forward higher requirements for the accurate design of MOF materials with optimal pore system.To address this issue,a novel MOF[Zn_(9)(tba)_(9)(dabco)_(3)]·12DMA-6MeOH(abbreviation:Zn_(9)(tba)_(9)(dabco)_(3);H_(2)tba=4-(1H-tetrazol-5-yl)-benzoic acid;dabco=1,4-diazabicyclo[2.2.2]octane;DMA=N,N-dimethylacetamide)with bcu network has been designed and synthesized by reticular chemistry strategy.Benefiting from the pre-designed topology and suitable linear ligand H_(2)tba and dabco,the structure of Zn_(9)(tba)_(9)(dabco)_(3)exhibits two types of channels with triangular-like and quadrilateral-like geometry.Zn_(9)(tba)_(9)(dabco)_(3)with appropriate channel size and shape displays potential selective adsorption capacity of vapor-phase hexane isomers through sieving effect.Moreover,outstanding gas adsorptive separation properties of Zn_(9)(tba)_(9)(dabco)_(3)could also be speculated by theoretical ideal adsorbed solution theory(IAST),suggesting Zn_(9)(tba)_(9)(dabco)_(3)can be regarded as a potential adsorbent material for purification natural gas_Breakthrough experiments show that Zn_(9)(tba)_(9)(dabco)_(3)is capable of discriminating all four hexane isomers at 298 K,and the corresponding research octane number(RON)of the eluted mixture closes to 95,which is higher than the standard for industrially refined hexane blends(about 83).We speculate that sieving effect and diffusion are a synergetic contributory factor in their elution dynamics,which may be ascribed to temperature-dependent interaction between pore aperture and each isomer.This work presents a typical example for design of efficient MOF absorbents by reticular chemistry strategy.

Construction of 3-Azabicyclo[3.1.0]hexane Backbone by the Reaction of Allenes with Allylamines via Tandem Michael Addition and Copper-Mediated Oxidative Carbanion Cyclization

Main observation and conclusion A facile synthetic method for the construction of 3-azabicyclo[3.1.0]hexane in the presence of copper catalyst system was developed.The reaction proceeds through Michael addition of allylamines with allenes followed by copper-mediated intramolecular oxidative carbanion 5-exo-trig radical cyclization,affording potential biologically active 3-azabicyclo[3.1.O]hexane derivatives in moderate to high yields(42%-85%).

Bioreduction of quinone derivatives by immobilized Baker's yeast in hexane

Immobilization techniques and biocatalytic transformations performed in organic media are new developing methods for organic reactions. Baker's yeast was immobilized on the alginate supports. This preparation contained about 20% of dry yeast cells. The immobilized Baker's yeast were found to be very effective in the reduction of o-benzoquinone, p-benzoquinones, naphthoquinones, and anthraquinones in hexane.

Athabasca 油砂沥青焦化蜡油中富氮组分的分离与表征(英文)

It is well known that gas oils from oilsands bitumen are difficult to hydrotreat. In order to develop the most appropriate flow sheet and operating conditions, a thorough knowledge of the molecular structure and behaviour of bitumen and its gas oil products is needed. In this work, the gas oil samples are fractionated in an attempt to isolate and identify the problematic molecular species for hydrotreating. It is found that the major nitrogen sources in coker gas oils are associated with relatively small pentane insoluble species and an even smaller, highly polar, hexane insoluble species. Structural information obtained for these fractions indicates that they are formed during the cracking of resin molecules. Nitrogen speciation shows that the pyrroles are the primary nitrogen type, with pyridines also being an important species. Both nitrogen species are undesirable in the hydrotreating process. Pyrroles in particular are subject to polymerisation, producing gums and sediments that foul filters and other equipment while pyridines can directly deactivate the hydrotreating catalyst.

Syntheses, Structures and Characteristics of Two New Cu(II) Coordination Polymers Based on 4-tert-butyl-phthalate and Different Bis(1,2,4-triazol-1-yl) Co-Ligands

Two new Cu（Ⅱ） coordination polymers, [Cu2（tbph）2（btb）2]n （1） and {[Cu2（tbph）2- （bth）2]·H2O}n （2）, （H2tbph = 4-tert-butyl-phthalic acid, btb = 1,4-bis（1,2,4-triazol-1- yl）butane, bth = 1,6-bis（1,2,4-triazol-l-yl）hexane）, have been synthesized and characterized by elemental analysis, FT-IR and X-ray single-crystal diffraction. Complex 1 has a 2D sql layer. Complex 2 shows a （3,4）-connected 2D sheet with a （4.6^4.8）（4.8^2） topology. The thermal behavior of the two cor- responding complexes has briefly been investigated.

Measurement Uncertainty Assessment of Magnesium Trisilicate Column for Determination of Sudan Colorants in Food by HPLC Using C8 Column

This study aimed to conduct measurement uncertainty assessment of a new method for determination of Sudan colorants（Sudan Ⅰ, Ⅱ, Ⅲ and Ⅳ） in food by high performance liquid chromatography（HPLC）. Samples were extracted with organic solvents（hexane, 20% acetone） and first purified by magnesium trisilicate（2Mg O·3Si O2）. The Sudan colorants（Sudan Ⅰ–Ⅳ） were also initially separated on C8 by gradient elution using acetonitrile and 0.1%（v/v） formic acid aqueous solution as the mobile phases and detected with diode-array detector（DAD）. The uncertainty of mathematical model of Sudan Ⅰ, Ⅱ, Ⅲ, Ⅳ is based on EURACHEM guidelines. The sources and components of uncertainty were calculated. The experiment gave a good linear relationship over the concentration from 0.4 to 4.0 μg/m L and spiked recoveries were from 74.0% to 97.5%. The limits of determination（LOD） were 48, 61, 36, 58 μg/kg for the four analytes, respectively. The total uncertainty of Sudan colorants（Sudan Ⅰ, Ⅱ, Ⅲ and Ⅳ） was 810±30.8, 790±28.4, 750±27.0, 730±50.0 μg/kg, respectively. The recovery uncertainty was the most significant factor contributing to the total uncertainty. The developed method is simple, rapid, and highly sensitive. It can be used for the determination of trace Sudan dyes in food samples. The sources of uncertainty have been identified and uncertainty components have been simplified and considered.

ON THE MURPHREE EFFICIENCIES IN THE SIMULATION OF MULTICOMPONENT DISTILLATION COLUMN:THE BIZARRE BEHAVIOUR AND THE ESTIMATION METHODS

The composition profiles in an I.D.30mm Oldershaw distillation column with 6 plates at total reflux weremeasured for two ternary systems,ethanol/chloroform/n-hexane and cyclohexane/n-heptane/toluene.Somecomponent effieiencies exhibit the bizarre behaviour,exceeding the normal range(0,1),at the plates near theextreme points of the concentration profiles of the components.The possible relationship between the extremeof the profiles and the bizarre values of component efficiencies has been analysed,and the feasibility and availa-bility of some approaches for the estimation of the component efficiencies are discussed.

CALCULATIONS OF VAPOR-LIQUID EQUILIBRIA FOR HYDROGEN-CONTAINING SYSTEMS WITH MODIFIED PENG-ROBINSON EQUATION OF STATE

Peng-Robinson equation of state was modified to represent vapor-liquid equilibria for hydrogen-containing systems. A new expression of the temperature dependent parameter for the supercritical gas hydrogen, and the binary interaction parameters were introduced to improve the description of VLE for 19 binary systems. Results show that this work is superior to the previous work. Moreover, estimations of PVT behavior, the second virial coefficients for hydrogen, and predictions of the volumetric properties of liquid mixtures and VLE for the ternary systems are in good agreement with the experimental data.

GC-MS Analysis of Low-polar Components and Antioxidant Activities of Vernonia divergens

[Objective]This study aimed to analyze the low-polar components and antioxidant activities of Vernonia divergens.[Method]After extraction,the relative contents of various components were calculated with peak area normalization method.In addition,V.divergens were extracted with n-hexane,ethyl acetate and n-butanol,respectively;DPPH scavenging capacity and reducing capacity of these three extracts were analyzed and compared with that of vitamin C.[Result]A total of 29 compounds were identified that accounted for 88.30%of the total amount of low-polar chemical components.The results indicated that n-butanol extract exhibited higher DPPH scavenging capacity and reducing capacity than ethyl acetate extract and n-hexane extract.[Conclusion]This study provided a theoretical basis for the development and utilization of V.divergens.

KINETIC STUDY OF THE CATALYTIC STEAM REFORMING OF PARAFFINS

Kinetics of the steam reformig of n-butane,n-hexane,n-heptane,n-nonane and i-octane on Z409 catalystwere studied at atmospheric pressure by using an internal recycle gradientless reactor.The reaction temperaturewas varied in the range of 743-853K,the steam carbon molar ratio 3-5.The experimental results showed thatthe reforming products contained no hydrocarbon other than methane.In addition,the product distributionof different n-paraffins were similar,but the product distribution of i-octane was different from that of n-paraffins.A reaction scheme for the steam reforming of paraffin has been proposed and the hyperbolic type rateequations were derived.It is clear that the obtained kinetic model could simulate the experimental results ofi-octane as well as different n-paraffins satisfactorily.

Catalytic Oxidation of Hexanol to Hexanal with H_2O_2 Over P-W Heteropoly Compounds

The syntheses of Keggin and Dawson-structural phospho-tungsto heteropoly compounds and their Peroxo-derivatives(PCWP), and the catalytic performance over this series of catalysts for the selective oxidation of hexanol to hexylaldehyde are reported. By means of IR, NMR and UV-DRS techniques the catalysts were characterized and a comparison of the structural properties of these catalysts before and after the reaction was made. The correlation between the catalytic performance and the structure of this series of catalysts was discussed as well.

Effects of hexanal fumigation on fungal spoilage and grain quality of stored wheat

The prevention of fungal spoilage is an essential consideration in wheat storage.Recent studies have revealed that volatile organic compounds(VOCs),possibly with natural fungicidal properties,could be produced from stored wheat grains.In this study,the antifungal effect of hexanal,a main component of VOCs from stored wheat,against spoilage fungi on agar plate and in high-moisture wheat grains were investigated via the gas fumigation method.And the impact of hexanal fumigation on grain quality was evaluated through analysis of the malondialdehyde content,fatty acid values,germination percentages and vigor of 16%and 18%moisture wheat grains fumigated with 1.66,2.49,and 3.31 mmol/L hexanal vapor.The results of in vitro antifungal experiments on agar plates revealed that the minimum inhibitory concentration and minimum fungicidal(fatal)concentration of hexanal against the five fungi were 4–14 folds and 4–7 folds lower than those of propionic acid,respectively.The fungal spoilage of high-moisture wheat grains inoculated with pure fungal spores and with naturally occurring fungi could be completely inhibited by 1.66 mmol/L hexanal vapor.During 5-week storage of high-moisture wheat grains fumigated with 1.66,2.49,and 3.31 mmol/L hexanal vapor,the malondialdehyde content in high-moisture wheat grains did not change significantly in all samples,and fatty acid values were slightly higher in 18%moisture wheat than in 16%moisture wheat.The germination percentages and vigor of wheat samples decreased with increased hexanal vapor concentrations and moisture content.These results indicated that hexanal fumigation could be used as an alternative chemical control method to prevent the fungal spoilage of postharvest wheat.

Optical evodiamine derivatives:Asymmetric synthesis and antitumor activity

Evodiamine and its derivatives have an asymmetric center at the C13 b position.Herein,isomers of evodiamine derivatives 2 and 3 were obtained by straightforward asymmetric total synthesis.Their inhibitory activities toward topoisomerases Ⅰ and Ⅱ and their cytotoxicities in cancer cell lines were evaluated.All the four isomers exhibited good to excellent antitumor potency and the（S）-isomers were generally more active than the（R）-isomers.The binding modes of（S）-2 with topoisomerases Ⅰ and Ⅱ were also clarified by molecular docking.

A novel synthesis of nitroform by the nitrolysis of cucurbituril

Cucurbituril has a high symmetry and rigid structure.When cucurbit[6]uril（CB[6]） was nitrolyzed with the mixed solution of acetic anhydride in fuming nitric acid,nitroform（NF） was generated.NF also can be obtained by the nitration of both CB[5,7,8].This nitration procedure provides a lower risk,inexpensive,new preparation of nitroform,and the reaction condition of this new method is very mild.

Syntheses of (C_5H_9C_5H_4)_2 LnCl(THF)_n and Crystal Structures of [(C_5H_9C_5H_4)_2SmCl(THF)]_2 and [(C_5H_9C_5H_4)_2ErCl]_2

Since 1980, organolanthanide chemistry of substituted cyclopentadienyl has been rapidly developed. Many substituted cyclopentadienyl lanthanoid chloride complexes have been synthesized. These sterically bulky ligands, such as-C5Me5, -（Me3Si）2C5H3,-t-BuCp, etc., can stabilize the complexes with low coordination number, especially the complexes of mono-and bin（substituted cyclopentadienyl） lanthanoid chloride. Using cyclopentylcyclopentadienyl as ligand, we synthesized Cp2′ LnCl（THF）n（Cp′=cyclopentylcyclopentadienyl, C5H9C5H4, Ln=Nd, Sm, n=1; Ln=Er, Yb, n=0）. Because the ligand is sterically bulky, it can not only prevent the disproportionation but also increase the solubil-

Study on a Water-soluble DMβCD-C_(60) Inclusion Complex

C60 （Buckminsterfullerene） is now one of the most notable carbon clusters. Recently Wennerstrm treated C60 with an aqueous solution of γ-CD （γ-cyclodextrin） under reflux and obtained a water-soluble γ-CD-C60 inclusion complex. But its composition was not reported. As a cyclodextrin derivative with high solubility in water, DMβCD （heptakis-（2, 6-di-o-methyl）-’β-cyclodextrin） has a cavity with similar dimension to γ-CD and