Presidential Green Chemistry Challenge: 2007 Greener Reaction Conditions Award
Headwaters Technology Innovation
Direct Synthesis of Hydrogen Peroxide by Selective Nanocatalyst Technology
Innovation and Benefits: Hydrogen peroxide is an environmentally friendly alternative to chlorine and chlorine-containing bleaches and oxidants. It is expensive, however, and its current manufacturing process involves the use of hazardous chemicals. Headwaters Technology Innovation (HTI) developed an advanced metal catalyst that makes hydrogen peroxide directly from hydrogen and oxygen, eliminates the use of hazardous chemicals, and produces water as the only byproduct. HTI has demonstrated their new technology and is partnering with Degussa AG to build plants to produce hydrogen peroxide.
Summary of Technology: Hydrogen peroxide (H2O2) is a clean, versatile, environmentally friendly oxidant that can substitute for environmentally harmful chlorinated oxidants in many manufacturing operations. However, the existing manufacturing process for H2O2 is complex, expensive, and energy-intensive. This process requires an anthraquinone working solution containing several toxic chemicals. The solution is reduced by hydrogen in the presence of a catalyst, forming anthrahydroquinone, which then reacts with oxygen to release H2O2. The H2O2 is removed from the solution with an energy-intensive stripping column and then concentrated by vacuum distillation. The bulk of the working solution is recycled, but the process generates a waste stream of undesirable quinone-derived byproducts that requires environmentally acceptable disposal.
Headwaters Technology Innovation (HTI) has produced a robust catalyst technology that enables the synthesis of H2O2 directly from hydrogen and oxygen. This breakthrough technology, called NxCatTM, is a palladium-platinum catalyst that eliminates all the hazardous reaction conditions and chemicals of the existing process, along with its undesirable byproducts. It produces H2O2 more efficiently, cutting both energy use and costs. It uses innocuous, renewable feedstocks and generates no toxic waste.
NxCatTM catalysts work because of their precisely controlled surface morphology. HTI has engineered a set of molecular templates and substrates that maintain control of the catalyst's crystal structure, particle size, composition, dispersion, and stability. This catalyst has a uniform 4-nanometer feature size that safely enables a high rate of production with a hydrogen gas concentration below 4 percent in air (i.e., below the flammability limit of hydrogen). It also maximizes the selectivity for H2O2 up to 100 percent.
The NxCatTM technology enables a simple, commercially viable H2O2 manufacturing process. In partnership with Degussa AG (a major H2O2 manufacturer), HTI successfully demonstrated the NxCatTM technology and, in 2006, completed construction of a demonstration plant. This demonstration plant will allow the partners to collect the data necessary to design a full-scale plant and begin commercial production in 2009. The NxCatTM process has the potential to cut the cost of H2O2 significantly, generating a more competitively priced supply of H2O2 and increasing its market acceptance as an industrial oxidant. Except for its historically higher price, H2O2 is an excellent substitute for the more frequently used—and far more deleterious—chlorinated oxidants. The NxCatTM technology has the benefit of producing an effective, environmentally preferable oxidant (H2O2) without the waste or high cost associated with the traditional process.