Fischer-tropsch synthesis in supercritical fluids. Quarterly technical progress report, October 1, 1994--December 21, 1994

Progress reports are presented for the following two tasks: (1) diffusion coefficients of F-T products in supercritical fluids; and (2) Fischer-Tropsch reaction related studies. The objectives for this quarter for task 1 were to measure molecular diffusion coefficients and effective diffusivities at the same conditions. The objectives for task 2 were to conduct two additional tests with the Ruhrchemie catalyst and a catalyst synthesized in our laboratory under supercritical conditions

Diffusion in Liquids

The recently developed Akgerman-Gainer equation to predict diffusion coefficients of gases in liquids employing significant liquid structure theory and absolute rate theory is modified and extended to estimate diffusivitles in liquid-liquid systems and compared with the Wilke-Chang equation. © 1976, American Chemical Society. All rights reserved

Styrene hydroformylation in supercritical carbon dioxide: Rate and selectivity control

Supercritical fluids have the unique characteristic of density-tuned physicochemical properties that can affect reaction rates and selectivities. We have studied homogeneously catalyzed styrene hydroformylation in supercritical carbon dioxide (scCO2) and have shown that the reaction rate and the regioselectivity can be varied by changes in pressure at constant temperature. This rate and selectivity change is explained in terms of the transition state theory. We have determined the partial molar volumes of the reaction products based on the Peng-Robinson equation of state for an infinite-dilution solution model, a real solution model, and a real solution model with regressed interaction coefficients. Then, the estimated partial molar volumes were used to predict the experimentally observed selectivity behavior. Through these simulations, an understanding of the reaction rate and selectivity control by adjustment of the pressure was developed.link_to_subscribed_fulltex

Fischer Tropsch synthesis in supercritical fluids. Quarterly technical progress report, July 1, 1995--September 30, 1995

Our objective for this quarter was to compare performance of the Ruhrchemie catalyst in different modes of operation: fixed bed reactor (conventional and supercritical mode of operation), and stirred tank slurry reactor. Diffusion coefficients are discussed

Mordant dyeing of wool by supercritical processing

WOS: 000090069700008Few studies have reported the use of supercritical fluids as solvents in dyeing of textile fibers. Studies on synthesis of new dyestuff that can be used in this technique and their solubility in the supercritical fluid are attracting increasing attention. In this study, wool fibers were dyed with mordant dyes dissolved in supercritical carbon dioxide. We used three mordant dyes that have chelating ligand properties, 2-nitroso-1-naphthol (C.I. Mordant Brown), 5-(4-aminophenylazo) salicylic acid (C.I. Mordant Yellow 12) and 1,2-dihydroxyanthraquinone (C.I. Mordant Red 11 also called Alizarin) which were dissolved in supercritical carbon dioxide, and five different mordanting metal ions, Cr(III), AI(III), Fe(II), Cu(II) and Sn(II). Wool fibers were mordanted by the metal using conventional techniques and dyed at 333-353 K temperature and at 150-230 atm pressure. Dyed materials had excellent wash fastness properties. (C) 2000 Elsevier Science B.V. All rights reserved

Fischer-Tropsch synthesis in supercritical fluids. Final report

The objective of this study was to investigate Fischer-Tropsch Synthesis (FTS) in the supercritical phase employing a commercial precipitated iron catalysts. As the supercritical fluid the authors used propane and n-hexane. The catalyst had a nominal composition of 100 Fe/5 Cu/4.2 K/25 SiO{sub 2} on mass basis and was used in a fixed bed reactor under both normal (conventional) and supercritical conditions. Experimental data were obtained at different temperatures (235 C, 250 C, and 260 C) and synthesis gas feed compositions (H{sub 2}/CO molar feed ratio of 0.67, 1.0 and 2.0) in both modes of operation under steady state conditions. The authors compared the performance of the precipitated iron catalyst in the supercritical phase, with the data obtained in gas phase (fixed bed reactor) and slurry phase (STS reactor). Comparisons were made in terms of bulk catalyst activity and various aspects of product selectivity (e.g. lumped hydrocarbon distribution and olefin content as a function of carbon number). In order to gain better understanding of the role of intraparticle mass transfer during FTS under conventional or supercritical conditions, the authors have measured diffusivities of representative hydrocarbon products in supercritical fluids, as well as their effective diffusion rates into the pores of catalyst at the reaction conditions. They constructed a Taylor dispersion apparatus to measure diffusion coefficients of hydrocarbon products of FTS in sub and supercritical ethane, propane, and hexane. In addition, they developed a tracer response technique to measure the effective diffusivities in the catalyst pores at the same conditions. Based on these results they have developed an equation for prediction of diffusion in supercritical fluids, which is based on the rough hard sphere theory

Fischer tropsch synthesis in supercritical fluids: Quarterly technical progress report, July 1, 1996-September 30, 1996

This report describes an equation for predicting diffusion coefficients in supercritical fluids and compares predictions therefrom with literature data. 56 refs., 10 figs., 3 tabs

Fischer-Tropsch synthesis in supercritical fluids. Quarterly technical progress report, January 1, 1996--March 31, 1996

Our objective in this quarter was to develop an equation to predict the molecular coefficients to a high degree of accuracy so we may be able to predict both the molecular diffusion coefficient and thus the effective diffusivity a priori. To accomplish this task we developed a correlation between the molecular dynamic simulations and semi- empirical correlation. A DEC alpha station was purchased for aid in this endeavor. With the new workstation the theory can be fully checked to a high degree of accuracy in a reasonable amount of time. Accomplishments for the development of the diffusion coefficients of F-T products in supercritical fluids are discussed

Solubility of disperse and mordant dyes in supercritical CO2

Waterless dyeing is the new approach in textile dyeing in order to reduce or eliminate effluent waste, and supercritical carbon dioxide is an alternative solvent being considered. The research focus has therefore been on determination of dyestuff solubilities in supercritical carbon dioxide. We have determined the solubilities of two disperse dyes (C. I. Disperse Yellow 7, C. I. Disperse Oranges 11) and three mordant dyes (C. I. Mordant Brown, C. I. Mordant Yellow 12, and C. I. Mordant Red 11) at 323-343 K and pressures in the range 132-195 bar. Mordant Brown had the highest solubility in the range (1.2-5.1) × 10-4 mole fraction whereas Mordant Yellow 12 had the lowest solubility in the range (1.7-5.1) × 10-7 mole fraction. The disperse dyes and Mordant Red had solubilities of the order 10-6 mole fraction. © 1999 American Chemical Society