Dow, Merck, Clarke Win Green Chemistry Challenge Awards

For the 15th year, the U.S. Environmental Protection Agency has recognized pioneering chemical technologies developed by leading researchers and industrial innovators who are making significant contributions to pollution prevention in the United States.

The Presidential Green Chemistry Challenge Awards recognize and promote green chemistry technologies, including cleaner processes; safer raw materials; and safer, better products. They also highlight the environmental and economic benefits of novel green chemistry.

The 2010 categories and award winners follow.

Greener Synthetic Pathways Award ─ The Dow Chemical Company, Midland, Mich., jointly with BASF, Florham Park, N.J., for "Innovative, Environmentally Benign Production of Propylene Oxide via Hydrogen Peroxide."

The Hydrogen Peroxide to Propylene Oxide (HPPO) process, developed by Dow and BASF, is a new, innovative route to PO based on the reaction of hydrogen peroxide and propylene. It has high yields and produces only water as a coproduct. The catalyst is a ZSM-5-type zeolite with channels of about 0.5 nm in diameter. In this catalyst, titanium replaces several percent of the silicon of the zeolite in a tetrahedral coordination environment. Propylene is epoxidized by hydrogen peroxide in a fixed-bed reactor at moderate temperature and pressure. The reaction occurs in the liquid phase in the presence of methanol as a solvent. Hydrogen peroxide is completely converted to product.

The process reduces the production of wastewater by as much as 70-80 percent and the use of energy by 35 percent over traditional technologies. The first commercial process based on this technology was commissioned in 2008 at the BASF production facility in Antwerp, Belgium. A second PO plant based on this technology is scheduled to begin production in Map Ta Phut, Thailand in 2011.

Greener Reaction Conditions Award ─ Merck & Co., Rahway, N.J., jointly with Codexis, Inc., Redwood City, Calif., for "Greener Manufacturing of Sitagliptin Enabled by an Evolved Transaminase."

Collaboration between Merck and Codexis has led to an improved, greener route for the manufacture of sitagliptin. Starting from an R-selective transaminase with some slight activity on a smaller, truncated methyl ketone analog of the sitagliptin ketone, Codexis evolved a biocatalyst to enable a new manufacturing process to supplant the hydrogenation route. The evolved transaminase had a compounded improvement in biocatalytic activity of over 25,000-fold, with no detectable amounts of the undesired, S-enantiomer of sitagliptin being formed. The streamlined, enzymatic process eliminates the high-pressure hydrogenation, all metals (rhodium and iron), and the wasteful chiral purification step. The benefits of the new process include a 56 percent improvement in productivity with the existing equipment, a 10-13 percent overall increase in yield, and a 19 percent reduction in overall waste generation. Sitagliptin is the active ingredient in JanuviaTM, an important treatment for type 2 diabetes.

Designing Greener Chemicals Award ─ Clarke Environmental Management, Roselle, Ill., for " NatularTM Larvicide: Adapting Spinosad for Next-Generation Mosquito Control."

Spinosad, a 1999 Presidential Green Chemistry Challenge Award winner, is an effective insecticide with excellent control in many terrestrial applications. Its instability in water, however, renders it ineffective for extended application in aquatic environments.

Clarke created a "sequential" plaster matrix that protects the spinosad molecule from water and releases it slowly, allowing extended performance of spinosad formulations for up to 180 days. This matrix is insoluble calcium sulfate hemihydrate plaster and water-soluble polyethylene glycol (PEG) binders fine-tuned for varying durations of insecticide release. The PEG dissolves slowly, exposing the spinosad and calcium sulfate to water. The calcium sulfate takes up the water to form the mineral gypsum and releases spinosad. Clarke formulated the plaster matrix for NatularTM larvicide entirely with approved pesticide inerts that also meet the U.S. Department of Agriculture's National Organics Standard. The resulting formulations provide excellent control of mosquito larvae in a range of aquatic environments from catch basins to salt marshes. Clarke manufactures the dustless, extended-release tablets with a solventless process that increases the environmental benefits.

The product is 15-fold less toxic than the organophosphate alternative, does not persist in the environment, and is not toxic to wildlife. Its manufacture eliminates hazardous materials and processes.

Academic Award ─ James C. Liao, Ph.D., Easel Biotechnologies, LLC and University of California, Los Angeles for "Recycling Carbon Dioxide to Biosynthesize Higher Alcohols."

Liao has developed a microbial technology to produce alcohols with 3-8 carbon atoms from carbon dioxide (CO2). His technology leverages the highly active amino acid biosynthetic pathway, diverting its 2-keto acid intermediates toward alcohols. With this technology, Liao and his group have produced isobutanol from glucose in near-theoretical yields with high efficiency and specificity. They also transferred the pathway into a photosynthetic microorganism, Synechococcus elongatus PCC7942, which produces isobutyraldehyde and isobutanol directly from CO2. The engineered strain produces isobutanol at a higher rate than those reported for ethanol, hydrogen, or lipid production by cyanobacteria or algae. This productivity is also higher than the current rate of ethanol production from corn. The technology shows promise for direct bioconversion of solar energy and CO2 into chemical feedstocks.

Small Business Award ─ LS9, Inc., South San Francisco, Calif., for "Microbial Production of Renewable PetroleumTM Fuels and Chemicals."

LS9 has developed a platform technology to produce a wide variety of advanced biofuels and renewable chemicals cost-effectively by a simple, efficient, one-step fermentation process. LS9 has engineered established industrial microorganisms to convert fermentable sugars selectively to alkanes, olefins, fatty alcohols, or fatty esters, each in a single-unit operation. The process enables precise genetic control of the molecular composition and performance characteristics of each resulting fuel or chemical product. The technology leverages the natural efficiency of microbial fatty acid metabolism to biosynthesize long hydrocarbon chains. It combines this with new biochemical pathways engineered into microorganisms to convert the long-chain intermediates into specific finished fuel and chemical products that are secreted by the cells. The products are immiscible with the aqueous fermentation medium and form a light organic phase that is both nontoxic to the whole-cell catalyst and easily recoverable by centrifugation.

The company is developing the technology for the production of alkanes (diesel, jet fuel, gasoline), alcohols (surfactants), esters (biodiesel, chemical intermediates), olefins (lubricants, polymers), aldehydes (insulation, resins), and fatty acids (soaps, chemical intermediates). Specific product performance is enabled through the genetic control of each product's chain length, extent of saturation, and degree of branching. The process does not require any metal catalysts.

LS9 is advancing toward commercial scale with its Renewable PetroleumTM facility, which will come on line this year. Initially, this facility will produce UltraCleanTM diesel; other products will follow.

An independent panel of technical experts convened by the American Chemical Society Green Chemistry Institute selected the 2010 winners from among scores of nominated technologies.

The Presidential Green Chemistry Challenge Program has reduced the hazards associated with designing, manufacturing, and using chemicals. During the life of the program, EPA has received more than 1,300 nominations and presented awards to 77 winners. Winning technologies alone are responsible for reducing the use or generation of more than an estimated 198 million pounds of hazardous chemicals, saving 21 billion gallons of water, and eliminating 57 million pounds of carbon dioxide releases to air.

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