Researchers have invented a new soap molecule from renewable sources that they say could dramatically reduce the number of chemicals in cleaning products and their impact on the environment. The molecule, patented by the University of Minnesota and licensed to startup company Sironix Renewables, also works better than some conventional soaps in challenging conditions such as cold and hard water, its inventors report.

Conventional soaps and detergents are generally viewed as environmentally unfriendly because they are made from fossil fuels. When formulated into shampoos, hand soaps or dishwashing detergents, these soaps are mixed with any number of harmful chemicals that are then washed down the drain.Air bubbles in a mixture of liquid water and OFS soap. Image credit: Paul J. Dauenhauer. Researchers from the University of Delaware's Catalysis Center for Energy Innovation have now developed a chemical process to combine fatty acids from soybeans or coconut, together with sugar-derived rings from corn, to make a renewable soap molecule called Oleo-Furan-Surfactant (OFS). They found that OFS works well in cold water where conventional soaps become cloudy and gooey, rendering them unusable. OFS soaps were also shown to form soap particles, or "micelles," necessary for cleaning applications at low concentrations, which significantly reduces the environmental impact on rivers and lakes.

In many locations around the world, minerals in the water can bind with conventional soaps and turn them into solid goo. To combat this problem, most existing soaps and detergents add an array of chemicals, called chelates, to grab these minerals and prevent them from interfering with soap molecules.

However, the new OFS soap eliminates the hard water problem by using a naturally derived source that does not bind strongly to minerals in water. The researchers found that OFS molecules form soap particles even at 100 times the conventional hard water conditions. As a result, a cleaning product’s ingredient list could be significantly simplified.

The researchers also used nanoparticle catalysts to optimize the soap structure for foaming and cleaning capabilities. In addition to its biodegradability and cleaning performance, OFS was shown to foam with the consistency of conventional detergents, which means it could directly replace soaps in existing equipment such as washing machines, dishwashers and consumer products.