(601f) Development of Reactive Chromatography Systems for Equilibrium-Limited Reactions

Authors: 
Oh, J., Georgia Institute of Technology
Bommarius, A. S., Georgia Institute of Technology
Kawajiri, Y., Georgia Institute of Technology
Donaldson, M. E., The Dow Chemical Company
Frank, T. C., The Dow Chemical Company
Agrawal, G., Georgia Institute of Technology



Reactive chromatography is a process that combines reaction and separation in a single unit that leads to a greater process performance and productivity [1]. This process is especially advantageous when the reaction is equilibrium limited, and the in-situ separation of product shifts the equilibrium in the direction of conversion increase [2].

In the present work, we study the application of reactive chromatography to the synthesis of an ester using AMBERLYST™ 15 as a catalyst and adsorbent. Among numerous esters, this study focuses on the production of propylene glycol methyl ether acetate (DOWANOL™ PMA glycol ether acetate), one of the most commonly used esters with a high industrial demand. DOWANOL™ PMA glycol ether acetate is the second-most used propylene glycol ether with nearly 90% of its use in surface coatings [3]. It is very efficient at dissolving resins used in paints, inks, lacquers, and other types of surface coatings such as in automotive, architectural, metal-coil, and industrial maintenance coatings [4]. Also, it is used in household products such as cleaners, paints (including spray paint), lacquers, varnishes, and pesticides. However, no study has been conducted on reactive chromatography for the formation of DOWANOL™ PMA glycol ether acetate, either through the esterification of 1-methoxy-2-propanol (DOWANOL™ PM glycol ether) with acetic acid or through the transesterification of DOWANOL™ PM glycol ether with ethyl acetate.

In this presentation, a case study of process development for an ester product is discussed. The dynamics of batch reaction and the fixed-bed adsorptive reaction are investigated by carrying out batch reaction experiments and chromatographic pulse tests. Stirred batch reactor experiments were conducted at various temperatures, stirring speeds, catalyst particle size and loading, and mole ratio of reactants. Reaction equilibrium and kinetic parameters together with their dependence on temperature were determined by fitting the model to the experimental data. Measurement of the adsorption equilibrium constant and reaction parameters were conducted by the pulse tests using a single chromatographic column. Since the resin acts as both adsorbent and catalyst, experiments were performed with nonreactive mixtures to obtain adsorption parameters first, and then reactive mixtures were injected to obtain reaction parameters. In addition to the development of model, the feasibility and efficiency of reactive chromatography where the conversion exceeds the reaction equilibrium of the batch reaction were demonstrated. 

References

[1] V. Gyani, S. Mahajani, Reactive Chromatography for the Synthesis of 2-Ethylhexyl Acetate. Separation Science and Technology, 43: 2245-2268, 2008.

[2] A. Rodigues, C. Pereira, J. Santos. Chromatographic Reactors. Chem. Eng. Technol. 2012, 35, No7, 1171-1183

[3] Dow Chemical Company. Product Safety Assessment 2008

[4] S.T. Cragg, R.J Boatman Patty’s Toxicology 2001 (7)