Aldol condensation of n‐butyraldehyde in a biphasic stirred tank reactor: Experiments and models

Abstract

To model a biphasic stirred tank reactor, intrinsic reaction kinetics and interfacial area are required. In this study, reactor modeling for n-butyraldehyde aldol condensation was investigated under industrially relevent conditions. The interfacial area in the reactor was directly measured using a borescope system under appropriate temperature, NaOH concentration and rpm conditions. To estimate the interfacial area, a semi-empirical correlation was developed, which provides good estimates within ±15% error. The reactor model based on two-film theory was developed, combining the interfacial area and intrinsic reaction kinetics reported in our prior work. The model was verified by reaction experiments in the range 0.05-1.9M NaOH, 80-130 o C and 600-1000 rpm. The prediction errors using the interfacial area from direct measurements and the correlation were ±8% and ±15%, respectively, suggesting that the model accuracy may be improved with better interfacial area estimation.Topical Area: Reaction Engineering, Kinetics and Catalysis

Evaluation of the Aldol Condensation of Propionaldehyde as a Reactive Dividing Wall Column Test System

“…These results showed a fast, first order reaction. 20,21 Since propionaldehyde, a C3, was expected to be more soluble than n-butyraldehyde in sodium hydroxide, the aldol condensation of propionaldehyde was expected to also be fast and first order. In order to model the propionaldehyde, its kinetics had to be determined.…”

Diacetone alcohol decomposition and benzaldehyde Cannizzaro reaction as test reactions for the basic strength measurements of alumina, magnesia, Amberlyst type resins (A-15, XN 1010, A-26, A-21), Nafion NR 50 and solid sulfuric acid

“…The last three reactants differ in the pK A values of hydrogen in the methylene group, which are 9, 11 and 13 respectively. This makes it possible to compare the basic strength of various solid catalysts; -the aldol condensation of butanal and isobutanal or acetone requires centers of basic strength equivalent to 13-14 pH units [9,10]; -transalcoholysis of ethyl acetate with methanol. The reaction requires the presence of basic centers of medium strength [8]; -the Michael condensation of cyclopentanecarboxylic acid, 2-oxo-, ethyl ester with methyl vinyl ketone [11].…”

Effect of pH and Concentrated Salt on the Droplet Size and Mass Transfer Coefficient in a Stirred Liquid–Liquid Reactor

“…Many studies have investigated the effect of temperature and pH on the Sauter mean diameter, − and the effect of the electrolyte has also been studied. − Some studies conducted experiments at nearly neutral conditions of pH 5–8 , and others at pH = 13 . However, actual industrial processes are run at much higher pH levels with NaOH concentrations higher than 0.5 M (pH > 13).…”

“…Sampling or encapsulation has also been frequently used, − but there still remained a possibility of droplet coalescence. On the other hand, a borescope system has been proposed ,, because it can minimize the distortion of the image and hydrodynamic effect in a reactor. We utilized the borescope system to directly measure the droplet size for the calculation of the Sauter mean diameter.…”