Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 30, 1999
Publication Date: N/A
Interpretive Summary: What sort of products make your clothes clean and your bathroom sparkle? Right now they're probably detergents and cleansers that make your eyes sting, your nose run, and the environment messy. Our lab is trying to create new detergents that are easier on people, animals and plants. We use oleic acid, an oil from sunflower seeds like cooking oil, to make ring-shaped structures called lactones. These white solids can be turned into everyday products like laundry detergent. However, unlike many soaps, these detergents are earth-friendly. They biodegrade, which means they break down, dissolve, and disappear once they enter the rivers or landfills. This way, fish can continue to swim without having soap suds clog their gills.
Technical Abstract: delta-Stearolactone was prepared from oleic acid using concentrated sulfuric acid under various conditions in the presence of polar, nonparticipating solvents. delta- Stearolactone was formed in as high as 15:1 ratios over the thermodynamic product, gamma-lactone, in the presence of methylene chloride, 100% w/v, at room temperature with two equivalents of sulfuric acid for 24 hours. This procedure is applicable to other olefinic fatty acids such as estolides and fatty acid methyl esters. Temperature plays a role in the regioselectivity of the cyclization for delta-lactone as lower temperatures (20 C) gave higher delta/gamma ratios. At higher temperatures (50 C) in the presence of sulfuric acid and methylene chloride the yield of lactone was 75% but with only 0.3 delta/gamma ratio. Cyclization of oleic acid to lactone also occurred with other acids. Oleic acid underwent reaction with perchloric acid, one equivalent, in the absence of solvent at 50 C, which yielded delta-lactone in a modest yield with a 3.1 delta/gamma ratio. The same temperature effect was observed with the perchloric acid that was observed in the sulfuric case. Because delta-stearolactone is much more reactive than the corresponding fatty acid, fatty acid ester or gamma-lactone, we believe that it will be a useful synthon for many new industrial products including new biodegradable detergents.