Industry Market Trends

Green Chemistry Carving a Bigger Role in Sustainable Manufacturing

May 30, 2012


Dave Kepler, chief sustainability officer at Dow Chemical Co., believes that to meet the demands of a burgeoning population, "we will need more sustainable products and infrastructure -- in short, a more sustainable economy."

Writing for GreenBiz, Kepler says "sustainable chemistry" will play a key role in meeting the increasing demands for material goods in an environment of tight resources and energy supply. He writes that more than 95 percent of manufactured goods rely on certain "chemical building blocks" somewhere in their value chains -- that is, basic chemicals from which other chemicals get made. For that reason, "integrating sustainability and green chemistry concepts -- 'sustainable chemistry' -- as a building block is a vitally important part of building a more sustainable economy."

Dow's sustainability strategy includes a set of four "pillars" of sustainable chemistry:

  • Holistic design -- a "cradle-to-cradle" approach to product design, considering the entire life cycle of the product from production to use to end of life
  • Atom economy -- regarding every atom as a valuable resource and creating processes in which nothing is wasted
  • Energy footprint -- minimizing life-cycle energy consumption of a product
  • Reduced hazard -- designing safety, health and environmental protection into products and processes

Kepler says Dow's green chemistry efforts have led to products such as roofing shingles with integrated photovoltaics that make harnessing the power of the sun affordable, advanced lithium-ion batteries for improved hybrid and electric vehicle efficiency, corn seed traits that increase crop productivity and a joint venture with Mitsui in Brazil to make plastics from sugar cane.

Biopolymer Efforts Are Valiant,

But Adds Pressure to Crop Capacity

That last detail -- making plastics from sugar cane -- is intriguing, especially in light of a recent article, "Status Report: Green Chemistry for Polymers," by Sally Humphreys of research firm Applied Market Information. The article discusses a wide variety of efforts in the plastics industry to employ biological substitutes for fossil fuels as feedstocks for producing polymers.

Humphreys also highlights efforts in Brazil to produce plastics from sugar cane:

The Brazilian sugar cane industry is the largest in the world. [Brazilian petrochemical firm] Braskem has used this sugar as a source of feedstock to make its "green" polyethylene and polypropylene with current capacities at 200 and 30 kilotonnes per year respectively. 86.5 tons of sugar cane gives 7,200 liters of ethanol and 3 tonnes of polyethylene. Brazil has vast areas of arable land that could be used to develop this industry and Braskem is studying all aspects including ways to increase yield.

Sugar cane

As another example, Ford Motor Co. has been testing the use of a soy polyol-based polyurethane foam, a bio-thermoplastic urethane (TPU) developed from renewable sources.

Humphreys uses the term "green chemistry" for these efforts and cites the involvement of corporate sustainability managers with them.

With fossil fuels still finding increasing demand and becoming harder to extract, it's understandable that industries would want to start investigating substitutes. But how sustainable is it, really, to divert agricultural crops into industrial value chains?

Humphreys acknowledges that, in considering bio-based chemicals, it's legitimate to ask, "Is it competing with the food chain?" She argues that, in the case of Ford's bio-polyurethane foam, "the United Soybean Board was keen to find a use for [soy polyol], as the bean was being grown for animal meal and oil was a side-product." Also, she says, the producers make use of "recycled materials and natural fiber reinforcements like hemp, sisal and wheat straw." The bio-TPU that Ford is employing produces 40 percent fewer greenhouse gas (GHG) emissions than conventional polyurethane.

Humphreys admits that agriculturally sourced polymers face potential supply conflicts. "One problem," Humphreys writes, "is the large number of cars produced, currently 4.8 million per annum, so any material specified must be available in considerable quantity."Agricultural land is already facing intensifying demand from rising food consumption worldwide, as well as from the growth of biofuel production.

Researchers are investigating how agriculture might be affected by the development of bio-based chemicals. Discussing the situation in Europe, Humphreys writes:

The question of sustainability revolves around the competition for land and the impact on agriculture. [Bioeconomy consultancy] NNFCC in York has studied crops for non-food use for many years and this is not novel -- 40 percent of sugars and starch in the EU are already grown for other purposes than food... around 250-800 million hectares of land are available for crops for bioenergy and fine chemicals excluding forest, protected areas and land for increased food production. The EU has renewable energy mandates that put pressure on the biomass supply chain. This makes predicting the future more difficult... The NNFCC overall prediction is that bio-based plastics will reach around 1 percent of the market by 2020 at 3-5 million tonnes, up to 10 percent by 2030 at 43 million tonnes and to 20 percent of the market in 2050 at 155 million tonnes.

EPA Supports, Lauds Green Chemistry


The United States Environmental Protection Agency (EPA) operates a "green chemistry" program, defining green or sustainable chemistry as "the design of chemical products and processes that reduce or eliminate the use or generation of hazardous substances" across the product life cycle. Green chemical products, according to the agency, employ less harmful and renewable feedstocks and reagents, result from processes that are less energy- and materials-intensive and are designed for easier reuse and recycling.

EPA supports green chemistry through projects, educational programs, research and especially by means of the Presidential Green Chemistry Challenge Awards. The awards program "recognizes chemical technologies that incorporate the principles of green chemistry into chemical design, manufacture and use," according to the agency.

EPA describes technologies that might qualify for its awards program:

Green chemistry technologies encompass all types of chemical processes including syntheses, catalyses, reaction conditions, separations, analyses and monitoring. A green chemistry technology can involve implementing incremental improvements at any stage. It can, for example, substitute a greener feedstock, reagent, catalyst, or solvent in an existing synthetic pathway. A green chemistry technology also can involve substituting an improved product or an entire synthetic pathway. Ideally, a green chemistry technology incorporates the principles of green chemistry at the earliest design stages of a new product or process. Benefits to human health and the environment may occur at any points in the technology's lifecycle: extraction, synthesis, use, and ultimate fate.

As an example, Dow and BASF jointly received a Green Chemistry Challenge Award in 2010 for their development of a technology to produce propylene oxide, a key chemical intermediate that can be used in home insulation, appliances, automobiles and furniture, as well as in products such as de-icers, paints, brake fluids and pharmaceuticals. The Dow-BASF innovation reduces wastewater by 70 to 80 percent and energy use by 35 percent. The only by-product is water.

The new technology requires less capital for facilities construction, because of "reduced infrastructure, a smaller physical footprint and simpler raw materials integration," according to Dow. Both companies have built plants based on the new technology.