Bubble Sizes in Agitated Water-Hydrophilic Organic Solvents for Heterogeneous Catalytic Reactions

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• 作者：Binjie Hu ; Alvin W. Nienow ; E. Hugh Stitt ; Andrzej W. Pacek
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2007
• 出版时间：June 20, 2007
• 年：2007
• 卷：46
• 期：13
• 页码：4451 - 4458
• 全文大小：462K
• 年卷期：v.46,no.13(June 20, 2007)
• ISSN：1520-5045

文摘

We recently reported that the rate of heterogeneous catalytic hydrogenation of 2-butene-1,4-diol using water,2-propanol, and mixtures of the two as the solvent under mass transfer controlled conditions is a maximumat ~5% 2-propanol, which also corresponds to the minimum bubble size. Here, bubble sizes are reported forother possible miscible water/hydrophilic solvents, along with some data with miscible hydrophobic/hydrophilicorganic liquids. Air has been dispersed in water, methanol, 1-propanol, 2-propanol, MEK, tert-butanol, andn-butyric acid, as well as in miscible mixtures of the two in a closed reactor containing 1% air, stirred witha Rushton turbine at 1200 rpm (29.5 W/kg). In all cases, a very marked minimum bubble size was found atlow concentrations of the hydrophilic organic. This concentration depends on the particular organic andcorresponds well with its maximum surface excess. This study is the first in which the surface excess hasbeen related to bubble behavior for mixtures of water and a wide selection of different potential hydrophilicsolvents. With miscible hydrophobic/hydrophilic organics, a minimum bubble size was not found. This workshould help solvent selection for heterogeneous catalytic reactions working in the mass transfer controlledregime.