399 resultados para American Chemical Society


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Vapor-liquid equilibrium data for the system n-heptane-n-butyl alcohol at pressures of 1445, 2205, 2965, and 3725 mm. of Hg have been reported. The data are correlated with Chao's modified Redlich-Kister equation.

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The kinetics of oxidation of acetaldehyde to acetic acid was studied in a sparger reactor using manganese acetate as the catalyst. Data obtained in a stirred tank reactor are used for analyzing the sparger reactor data. The rate of chemical reaction is extremely fast and can be neglected for the rate equation of the sparger reactor. A kinetic model applicable at any temperature and concentration within the range of the variables studied is developed which predicts the performance of the sparger reactor satisfactorily.

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Vapor-liquid equilibrium data for the systems diisopropyl ether-n-heptane and diisopropyl ether-carbon tetrachloride have been reported at pressures of 760, 1520, and 2280 mm. of Hg. The systems form ideal mixtures under the pressure range studied.

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The viscosity of five binary gas mixtures - namely, oxygen-hydrogen, oxygen-nitrogen, oxygen-carbon dioxide, carbon dioxide-nitrogen, carbon dioxide-hydrogen - and two ternary mixtures - oxygen-nitrogen-carbon dioxide and oxygen-hydrogen-carbon dioxide - were determined at ambient temperature and pressure using an oscillating disk viscometer. The theoretical expressions of several investigators were in good agreement with the experimental results obtained with this viscometer. In the case of the ternary gas mixture oxygen-carbon dioxide-nitrogen, as long as the volumetric ratio of oxygen to carbon dioxide in the mixture was maintained at 11 to 8, the viscosity of the ternary mixture at ambient temperature and pressure remained constant irrespective of the percentage of nitrogen present in the mixture.

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A new equation for predicting the thermal conductivities of organic liquids using dimension-less analysis is given. The equation (Equation Presented) correlates 51 different liquids tested within 11% average error and 17% standard deviation. A comparison of the proposed equation with the available correlations and its application to some industrially important liquids show that this equation can be safely used to calculate the thermal conductivities at 20°C. and 1 atm. pressure for organic liquids of known molecular weight. Cp and ΔHv - the only two parameters for which experimental values must be known for making use of this equation - can be calculated using other well known correlations. The proposed equation is not applicable to inorganic liquids.

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A semitheoretical equation for latent heat of vaporization has been derived and tested. The average error in predicting the value at the normal boiling point in the case of about 90 compounds, which includes polar and nonpolar liquids, is about 1.8%. A relation between latent heat of vaporization and surface tension is also derived and is shown to lead to Watson's empirical relation which gives the change of latent heat of vaporization with temperature. This gives a physico-chemical justification for Watson's empirical relation and provides a rapid method of determining latent heats by measuring surface tension.

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Fugacity coefficients and isothermal changes of enthalpy have been calculated and reported. The calculations cover a temperature range of 0° to 75°C. up to gas densities of 1.0 gram per cc. The generalized Benedict-Webb-Rubin constants evaluated from generalized PVT relations is found to predict the experimental data with an over-all absolute deviation of 3.1%. Second virial coefficients and potential energy parameters for Lennard-Jones (12-6) potential energy function are reported also.

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Vapor-liquid equilibrium data for the system n-heptane-n-butanol have been reported. The thermodynamic consistency of the data was tested with Chao's modified Redlich-Kister equation and Tao's method.

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The vapor phase hydrochlorination of methanol to methyl chloride in fixed beds with silica gel-alumina (88 to 12) and γ-alumina catalysts was studied in a glass tubular reactor in the temperature range of 300° to 390°C. Of the two catalysts studied, γ-alumina gave nearly equilibrium conversions under the experimental conditions. The data are expressed in the form of second-order irreversible rate equations for both the catalysts studied.

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Several methods were developed for converting isodigitoxigenin (2a) into methyl acetals 4b and 4c. Of these, methanolysis (followed by acetylation) of isodigitoxigenin in the presence of p-toluenesulfonic acid proved most useful. Each isomer reached an equilibrium corresponding to ca. 3:1 acetal 4c to 4b within 15 min in benzene containing p-toluenesulfonic acid. Addition of dihydropyran to the equilibrium mixture resulted in excellent conversion into vinyl ether 5a. Heating either acetal 4b or 4c in benzene containing p-toluenesulfonic acid led to a skeletal rearrangement culminating in formation of C-norcardenolide 6. In addition to results of physical measurements, the structure of spiran 6 was confirmed by degradation to methyl ketone 8. Similar rearrangement of isodigitoxigenin gave spiran 9 accompanied by C-norcardenolide 6. Treating lactone 9 with p-toluenesulfonic acid in methanol-water provided acetals 10a and 10b, which on further contact with p-toluenesulfonic acid in refluxing benzene gave lactone 9 and cardenolide 6. Evidence underlying the stereochemical assignments noted for structures 4, 9, and 10 was also discussed.

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Lithium amalgam is useful in effecting Wurtz type intramolecular and intermolecular coupling reactions.

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A method for the delipidation of egg yolk plasma using phospholipase-C, n-heptane, and 1-butanol has been described. An aggregating protein fraction and a soluble protein fraction were separated by the action of phospholipase-C. The aggregating protein fraction freed of most of the lipids by treatment with n-heptane and 1-butanol was shown to be the apolipoproteins of yolk plasma, whereas the soluble proteins were identified as the livetins. Carbohydrate and the N-terminal amino acid analysis of these protein fractions are reported. A comparison of these protein fractions with the corresponding fractions obtained by formic acid delipidation of yolk plasma has been made. The gelation of yolk plasma by the action of phospholipase-C has been interpreted as an aggregation of lipoproteins caused by ionic interactions. The role of lecithin in maintaining the structural integrity of lipoproteins has been discussed.