“Greener” gasoline

The method substitutes a solid-acid catalyst for a liquid one. The solid-acid is a component of manmade pellets called zeolite catalysts. Using this substance reduces the chance of the environment being harmed by a concentrated acid.

While the catalyst works well, over time its surface gums up with unwanted byproducts. A supercritical fluid can restore the catalyst activity, but more research is necessary before the method is put into action.