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91.
92.
Michel Renou Bernard Lalanne-Cassou Didier Michelot Ginette Gordon Jean-Christophe Doré 《Journal of chemical ecology》1988,14(4):1187-1215
Female-emitted pheromones and sex attractants of Noctuidae were investigated using a specific computer procedure to analyze data collected from the literature. Correspondence analysis was used to survey the structure-activity relationships of sex pheromones in seven subfamilies. Structural, stereochemical, and functional features of active molecules were related to taxonomy. This multidimensional analysis revealed that the prevalent chemical frame of noctuid moth pheromones was a monounsaturated acetate withZ stereochemistry and a double bond on the fifth carbon closest to the nonfunctional branch of the molecule. Possible phylogenetic relationships within Noctuidae and between Noctuidae and other families are discussed in light of the sex pheromone biochemistry. Female sex pheromones appeared to be an additional character to be considered in the classification of noctuid moths. 相似文献
93.
Owing to its well-known high complexing power toward Al3+ ion, fluoride ion is able to increase the solubility of alumina in alkali chloride melts. To determine the extent of this effect, the formation of aluminium(III) fluoro-complexes was studied potentiometrically in LiCl-KCl eutectic at 470°. But the sodium fluoride addition appeared to produce not only the complexation effect but also a mineralization effect on alumina. So, the thermodynamical stability of alumina formed in this melt by precipitation from aluminium chloride with carbonate ion (oxide anion donor) depends on the fluoride ion concentration. These two effects explain the solubility variation of alumina in the LiCl-KCl eutectic + NaF mixtures. A pF? - pO2? diagram, which represents the stability area of the various aluminium (III) species is established, and leads to some conclusions concerning the electrowinning of aluminium from molten chloride melts.The cumulative formation constants of the aluminium(lII) fluoro-complexes (AlF3?ii) have been obtained, whose values are the following: 2.5 ± 0.4, 4.7 ± 0.6, 5.7 ± 0.5, 7.5 ± 0.4, 8.0 ± 0.5, 9.0 ± 0.6, respectively for i = 1, 2, 3, 4, 5 and 6. It has been shown that oxyfluoride species such as AlOF1?ji does not exist. The solubility products of gamma and alpha-alumina have been determined and are equal to 10?42.9 and 10?44.0 respectively (all the constants are given in the molality scale). They differ widely from the solubility product of the alumina obtained in the absence of fluoride ion, ie 10?27.4. 相似文献
94.
本文报道了p-(N,N-二甲氨基)肉桂酸乙酯(DMAC)在十二酸(LA)聚集体中的光谱和光化学性质.这种肉桂酸衍生物的吸收和发射光谱表现出典型的分子内电荷转移的特征,在十二酸存在下,观察到DMAC激基缔合物荧光,荧光强度随DMAC浓度增加而增加,与普通溶液中的反应相比,十二酸聚集体中的DMAC具有较大的光二聚反应速度.用荧光光谱跟踪反应的结果表明,DMAC激基缔合物具有较DMAC单体更高的光化学活性。 相似文献
95.
96.
The influence of drop coalescence and breakup on the existence of multiple steady states is studied for a two-phase stirred isothermal reactor where the chemical reaction in the d?ispersed phase obeys the rate expression ? r = kC/(1 + KC)2. The random coalescence model developed by Curl was simulated using a modified Spielman and Levenspiel Monte Carlo technique.For certain range of the coalescence rate, Damköhler number, and dimensionless feed concentration, multiple steady states have been investigated.A special case has also been considered wherein the existence of multiple steady states for finite values of the coalescence rate is contrasted to the unique steady state solution for an infinite coalescence rate. 相似文献
97.
不同的双-(p-N,N-二甲氨基苄叉)酮DMBK和二苯基碘盐(DPIOF)复合,组成一种新型的电子转移光显色体系,DMBK/DPIOF复合体系在暗处有良好的热稳定性。在光作用下很快发生从激发态DMBK至DPIOF的电子转移,并伴随DMBK染料的褪色,测得DMBK光褪色速度的次序为:DMBA>DMBP>DMBH。与此同时,电子转移又引起新的光显色反应,对DMBA化合物,在700nm处出现新吸收峰。其光密度随光照时间而增长,然而,DMBP和DMBH体系这种光显色现象并未观察到,这可能由于它们的中间产物不能共平面的缘故,DMBA的光显色速度和最大密度明显取决于浓度和溶剂性质。本文对这种短波区光褪色和长波区光显色的光化学反应过程作了讨论。 相似文献
98.
Mass transfer rates were determined in a 3.4 cm i.d. trickle-bed reactor in the absence of reaction by absorption measurements and in presence of reaction. Gas flow rates were varied from 0-100 l/h and liquid flow rates from 0-1.5 l/h. The catalyst particles were crushed to an average diameter of 0.054 and 0.09 cm. Mass transfer coefficients remained unaffected by change in gas flow rate but increased with liquid rate. The data from absorption measurements were evaluated with predictions based upon plug-flow and axial dispersion model. Mass transfer coefficients were found greater in case of axial dispersion model than that of plug-flow model specially at low Reynolds number (Re1 < 1).Hydrogenation of α-methylstyrene to cumene using a Pd/Al2O3 catalyst was taken as a model reaction. Intrinsic kinetic studies were made in a laboratory-stirred-autoclave. Mass transfer coefficients were determined using these intrinsic kinetic data from the process kinetic measurements in trickle-bed reactor. Mass transfer coefficients under reaction conditions were found to be considerably higher than those obtained by absorption measurements.Correlations were suggested for predicting mass transfer coefficients at low Reynolds number.The gas to liquid mass transfer coefficients for lower gas and liquid flow rates were determined in a laboratory trickle-bed reactor. The effect of axial dispersion on mass transfer was considered in order to evaluate the experimental data. Three correlations were formulated to calculate the mass transfer coefficients, which included the effect of liquid loading, particle size and the properties of the reacting substances. The gas flow rate influences the gas to liquid mass transfer only in the region of low gas velocities. In the additional investigations of gas to liquid mass transfer without reaction in trickle-bed reactor, the mass transfer coefficients were determined under reaction conditions and the intrinsic kinetics was studied in a laboratory scale stirred autoclave with suspended catalyst. A few correlations are formulated for the mass transfer coefficients. A comparison with the gas-liquid mass transfer coefficient obtained by absorption measurements showed considerable deviations, which were illustrated phenomenologically. 相似文献
99.
100.