Sugary Catalyst for Biodiesel

A new solid acid catalyst for making the increasingly popular fuel biodiesel trumps other catalysts, report Masakazu Toda at Tokyo Institute of Technology in Yokohama and colleagues. Made from sulfonated burnt sugar, the catalyst is inexpensive and recyclable and keeps working at temperatures up to 180 °C (Nature 2005, 438, 178). Unlike sulfuric acid, the commonly used catalyst, the new catalyst is environmentally friendly; and because it's solid, it doesn't require separation. It's also up to eight times more active than other solid acid catalysts, such as the expensive Nafion, made by DuPont. The Japanese group first partially carbonizes sugar, starch, or cellulose. The reaction generates polycyclic aromatic carbon sheets, which are then sulfonated with sulfuric acid to produce sheets of amorphous carbon impregnated with hydroxyl, carboxyl, and sulfonite (SO₃H) groups. The resulting black powder can be made into hard pellets or thin films. That is a useful property for large-scale biodiesel production, notes James G. Goodwin, chair of the chemical and biomolecular engineering department at Clemson University, in South Carolina.