Activity Coefficients for Liquid Organic Reactions: Towards a Better Understanding of True Kinetics with the Synthesis of Jasmin Aldehyde as Showcase

Abstract

The aldol condensation of benzaldehyde and heptanal is taken as an example of reversible liquid phase organic reactions to show that inclusion of activity coefficients reveal distinct differences in conversion and product distribution when different solvents methanol, ethanol, n-propanol, or n-butanol are used. The purpose of this work is to show a pronounced solvent effect for a given set of identical kinetic parameters, i.e., the same liquid phase kinetics can result in different conversion and yield values, depending on the choice of solvent. It was shown that subsequent parameter estimation without inclusion of the activity coefficients resulted in a pronounced deviation from the ‘true’ kinetics, up to a factor of 30. It is proposed that the usage of average activity coefficients gives already a significant improvement, resulting in acceptable parameter estimates.

The Physical Chemistry and Chemical Physics (PCCP) Section of the International Journal of Molecular Sciences in Its Publications: The First 300 Thematic Articles in the First 3 Years

“…Thematic Area 2 includes 22 articles, namely [ 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 ], the typification of which is shown in Table 3 . With some degree of conventionality, it is possible to subdivide the articles published here into two main groups, namely, articles devoted to the study of the kinetics of processes in which any chemical transformations are decisive, and articles devoted to the study of the kinetics of processes in which chemical transformations are either not decisive or absent altogether.…”

“…With some degree of conventionality, it is possible to subdivide the articles published here into two main groups, namely, articles devoted to the study of the kinetics of processes in which any chemical transformations are decisive, and articles devoted to the study of the kinetics of processes in which chemical transformations are either not decisive or absent altogether. Among the articles of the first group, in turn, two categories can be distinguished, in the first of which are the clear majority; the processes related to them were considered in the articles [ 29 , 30 , 31 , 32 , 33 , 35 , 37 , 42 , 43 , 44 , 45 , 46 , 47 ]. For example, in [ 29 ], the kinetics of the aldol condensation of benzaldehyde and heptanal in liquid-phase systems using various solvents was characterized, and a very pronounced effect of the solvent was noted for a given set of identical kinetic parameters (i.e., the same kinetics of the liquid phase can lead to different values of conversion and yield of reaction products depending on the choice of solvent).…”

“…Among the articles of the first group, in turn, two categories can be distinguished, in the first of which are the clear majority; the processes related to them were considered in the articles [ 29 , 30 , 31 , 32 , 33 , 35 , 37 , 42 , 43 , 44 , 45 , 46 , 47 ]. For example, in [ 29 ], the kinetics of the aldol condensation of benzaldehyde and heptanal in liquid-phase systems using various solvents was characterized, and a very pronounced effect of the solvent was noted for a given set of identical kinetic parameters (i.e., the same kinetics of the liquid phase can lead to different values of conversion and yield of reaction products depending on the choice of solvent). It was shown that the subsequent assessment of the parameters without taking into account the activity coefficients led to a pronounced deviation from the “true” kinetics up to 30 times.…”

Solvent-Free Synthesis of Jasminaldehyde in a Fixed-Bed Flow Reactor over Mg-Al Mixed Oxide

“…After attacking the α-C atom of benzaldehyde with enolate anion, an intermediate alkoxide is formed, which quickly deprotonates a water molecule and produces hydroxide and aldol product or a β-hydroxyaldehyde. Both acidic and basic sites cooperate for the production of jasminaldehyde [9,13]. Self-condensation of heptanal also resulted in the formation of 2-n-pentyl-2-n-nonenal during the reaction.…”

“…Owing to the lower price of synthetic materials, their higher stability in acidic, basic, and even oxidizing media, these compounds became more attractive to be used in the synthesis of perfumery chemicals [2]. Jasminaldehyde can be synthesized via the cross aldol condensation of heptanal (C 7 H 14 O) and benzaldehyde (C 7 H 6 O) (Scheme 1), and this process has been intensively studied by researchers to enhance the yield of jasminaldehyde [3][4][5][6][7][8][9][10]. In addition to jasminaldehyde, the self-condensation of heptanal resulted in the formation of 2-n-pentyl-2-n-nonenal (C 14 H 26 O) as the main by-product of this reaction.…”