Direct esterification catalyzed by zinc catalysts

Authors: Knetzer, Taegan; Winfield, Demichael

Submitted to: Meeting Abstract
Publication Type: Other
Publication Acceptance Date: 2/28/2025
Publication Date: 3/27/2025
Citation: Knetzer, T.R., Winfield, D.D. 2025. Direct esterification catalyzed by zinc catalysts [abstract]. Bradley University, Senior Seminar, March 27, 2025, Peoria, IL.

Interpretive Summary:

Technical Abstract: Esters are important to industry and consumers because of their diverse use in products such as biodiesel additives, cosmetics, fragrances, foods, lubricants, solvents, and polymers. Alkenes in combination with carboxylic acids will produce an ester with the use of a green catalyst through the process of direct esterification. Direct esterification is more aligned with the 12 green principles of chemistry compared to typical methods of esterification which uses strong acidic catalysts that yield toxic byproducts. Zinc has the properties of a green catalyst since it is earth-abundant. Several zinc catalysts selected to be used include: ZnI2, Zn(BF4)2, ZnBr2, Zn(SO4) * 7 H2O, and Zn(OTf)2. Hexanoic acid, 1-decene, which can be derived from triglycerides, and a catalyst were vacuum refluxed at 100 deg. C. for 24 hrs. or until solidified. GC-FID, GC-MS, H-NMR, and C-NMR were used to measure the selectivity and conversion rates for the reaction producing 1-methyl hexanoate. ZnBr2 in combination with p-Toluenesulfonic acid in 20%, 10%, 5%, and 1% molar ratios resulted in the highest conversion and selectivity rates. Next, reactions will be tested with different solvents, under non-vacuum reflux conditions, and with various carboxylic acids and alkenes.