San Francisco -- The Cleantech Open – sort of an American Idol with soil scientists andsolarcompanies – is taking place today in San Francisco, and green chemistry seems to be one of the more interesting topics at the event.

The organization seeks out small startups in efficiency, power generation and other green technology fields and then shows them off at its annual gala event. It used to concentrate on California but now it covers the western U.S. Alumni include Nila, which makes LED spotlights, and Adura Technologies. This year, finalists include Armageddon Energy, which has come out of stealth mode.

So far, nearly every interesting company I've seen offers a green chemical. Such as:

• Rivertop Renewables: The company, run by a father and son team from Montana, has come up with an efficient way to produce glucaric acid, which can be substituted for phosphates or citric acid in detergents. Phosphates are being phased out because they represent an environmental hazard while citric acid doesn't perform optimally, said Don Kiely, the founder and a former professor at the University of Montana.

Glucaric acid, derived from glucose, can also be added to the water in HVAC systems to reduce corrosion, or it can be added to the salt brine sprayed on roads to inhibit car and bridge corrosion. Several researchers have tried to commercialize glucaric acid, but it hasn't succeeded because the conversion process can consume an inordinate amount of catalysts. Rivertop recovers almost all of the nitric acid used in its process.

"There has never been a wide-scale commercial method to do this conversion," he said. "I had the luxury [as an academic] to see the obvious."

Glucose comes from cornstarch, but the price remains relatively stable at 8 to 10 cents a pound, he added. Rivertop is currently seeking commercial partners.

• A-Z Comp: This company, from Russia, exploits graphene, a type of carbon molecule, to clean up oil spills. (Video will be posted shortly.) "Scientists in labs can make graphene, but we are the only ones to produce it in production quantities," said Calisher Abdul, the CEO.

• Solar Alchemy: Fantastic idea, odd name. The company takes recyclable waste paper, runs it through a thermo chemical reactor, and converts it into a toluene (a chemical made from fossil fuels) and two other chemicals. Ninety-five percent of the paper sludge gets resold as chemicals, says Michael Hurwitz, the chief science officer.

Economically, it fits well with current market conditions. The world is awash in recyclable paper. Recycled paper sells for around $120 a ton, but it takes $80 a ton to get it to docks. By converting it into chemicals, waste management companies can convert it on site, sell it for a higher value, and cut down on transportation costs. A $2.5 million plant could convert 40,000 tons of paper a year and produce $13 million in chemicals.

So why the solar name? The system can run on a solar thermal generator.

• Micromidas: Great name, but a tougher concept to pull off. The UC Davis spin-out (created by undergraduates) wants to convert sewage into a precursor for bioplastic. The conversion process is accomplished by biological process. The sewage gets fed to organisms. (A number of other companies and researchers are examining ways to generate minerals, drinking water and other substances from sewage.)

Interestingly, Micromidas does not rely upon a sole microorganism or a genetically modified organism. Instead, the sewage gets converted by a multicultural mix of organisms. The challenge, though, will lie in keeping the microorganism populations stable and ensuring that the output remains consistent. Neither of these tasks will be easy.

Right now, Micromidas wants to raise enough money to build a prototype that can covert 1,000 liters a year in to plastic precursors. They hope to take it to different sewage facilities on a dolly.

• Homergent: The company actually makes a portable house. Nothing to do with green. But its product is called Flexayurt, which should win an award just for that.