Esterification / De-esterification

Ester formation and hydrolysis is commonly practiced with homogeneous acid catalysts. The direction of the reaction is determined by the amount of water that is present. A typical reaction is shown below.

In many cases, getting the water and organic to the same place at the same time is a problem with homogeneous catalyst systems. In these cases, heterogeneous acid catalysts offer several advantages. While immobilized acid catalysts are hygroscopic due to the high level of acid groups immobilized on the plastic, the starting level of moisture in the catalyst can be controlled in the preparation of the catalyst. When ester hydrolysis is desired, the catalyst is used in a wet form where the moisture content is set at the optimal solubility of the reactants with the catalyst. When ester formation is desired, the catalyst is used in the dry form. The hygroscopic nature of the catalyst actually draws moisture away from the reaction and limits ester hydrolysis.

Applications and Products

DOWEX™ catalysts are versatile tools to catalyze a wide variety of reactions from aldol condensations, alcohol-alkene condensations, alcohol dehydration, hydrolytic cleavage of epoxides, isomerization of allylic compounds, and polymerizations, to name only a few.

For dry reactions such as ester formation, Dow offers the pre-dried DOWEX DR-2030 and DOWEX MONOSPHERE™ DR-2030 catalysts.

For reactions where water is needed as a reactant, Dow offers the wet form as DOWEX M-31 and DOWEX MONOSPHERE M-31 catalysts. For more information, please go to MTBE / TAME.

For some specialty applications, standard particle size and cross-linked catalysts are kinetically inhibited and will not work because the particles are too large or the matrix too highly crosslinked for good performance. In these cases, the wide selection of catalysts that Dow offers for specialty applications may be a fit. Dow offers a wide variety of fine mesh resins (183KB PDF) with varying levels of cross-linking that allow interaction of the catalyst site with these cumbersome alkyl groups. Cross-linking levels range from 2 to 8% and particle sizes from 300 microns to 37 microns.

Assistance with Process Development. Dow has a staff of experienced process development experts that represent decades of process expertise. For help, please contact us.

DOWEX Esterification / De-esterification Products

Product	Description	Type	Matrix	Total Exchange Capacity* eq/l (kgr/ft3)	Available Forms
DOWEX DR-2030	Dry acid catalysts for chemical processing.	Strong Acid Cation	Styrene-DVB, Macroporous	4.7 eq/kg	H+
DOWEX MONOSPHERE DR-2030	Dry acid catalysts for chemical processing.	Strong Acid Cation	Styrene-DVB, Macroporous	4.7 eq/kg	H+
DOWEX M-31	Standard grade product for general catalytic applications. This catalyst has unmatched durability and dependability within the MTBE/TAME industry.	Strong Acid Cation	Styrene-DVB, Macroporous	1.7	H+
DOWEX MONOSPHERE M-31	A uniform bead size strong acid catalyst. This is our highest performance catalyst for MTBE/TAME.	Strong Acid Cation	Styrene-DVB, Macroporous	1.85	H+