Contributed by James Oristian, 2015 ACS Green Chemistry Institute® Summer Intern
The theme of this month’s Nexus Newsletter is climate change, and how green chemistry can improve our relationship with our atmosphere. The earth is warmed by the sun in a process known as solar radiation, and this heat can either be absorbed by the earth’s crust or reflected into space. The problem arises when the heat reflected off the earth is trapped by gases expelled by humans that are trapped between earth and space. These gases with global warming potential (GWP) are some compounds that you may be familiar with, such as carbon dioxide, methane, and ozone, as well as lesser known contributors like Volatile Organic Compounds (VOCs). Of course there are small things individuals can do to make an impact- use less water, turn off lights when not in use-but what about large-scale, upstream impact? That’s where green chemistry takes the spotlight.
The chemical industry and transportation are two of the largest contributors to this greenhouse effect due to their expulsion of the compounds listed above, which makes the emergence of green technology even more vital. In the US alone, 6,673 Million Metric Tons of CO2 was released in 2013, with 21% of that volume attributed to industrial sectors, and 27% due to transportation. To combat the growing levels of GWP gases, the chemical and transportation industries must look to green chemistry as a superhero, and the US EPA has granted companies and individuals that promote environmental and economic benefits of using greener chemistry with the Presidential Green Chemistry Challenge Award (PGCCA). But who are the heroes behind the mask?
One of the lesser known, but hazardous group of compounds that contribute to climate change are VOCs. They have high vapor pressure in ambient conditions, which causes them to evaporate or sublimate easily as gases. These gases are found in a wide variety of common products like paints, cleaning supplies, pesticides, glues, adhesives and fuels. Environmentally, these gases can be problematic because they can react with nitrogen oxides in the atmosphere to form ozone, a large contributor to global warming, as well as smog. Some VOCs are known carcinogens and present other health hazards.
So what’s to be done? Two prominent companies recognized by the EPA that are committed to reducing VOC emissions are Proctor & Gamble and the Sherwin-Williams Company. Sherwin-Williams was recognized in 2011 by the EPA for the development of a Water-based Acrylic Alkyd Technology in the Designing Greener Chemicals award category. Instead of their paints being oil-based alkyd solutions that release VOCs when paint dries, Sherwin-Williams combined recycled polyethylene terephthalate (PET) from recycled soda bottles, acrylics and soybean oil to manufacture a more environmentally friendly paint. The technology used low-VOC alkyd-acrylic dispersion technology, with PET polymers for rigidity, acrylics for drying and soy bean oil to promote film formation and gloss. The final product had superior quality but lacked the harmful components of typical paints. Since the time of the launch of their products ProClassic Waterbased Acrylic Alkyd, ProMar 200 Waterbased Acrylic Alkyd, and ProIndustrial Waterborne Enamel in 2010, Sherwin-Williams eliminated the use of 800,000 pounds of VOC solvents and petroleum-based feedstocks.
But Sherwin-Williams wasn’t the only major company to hop on the anti-VOC bandwagon. Proctor & Gamble Company and Cook Composites & Polymers Company won the PGCCA award in 2009 for Designing Greener chemicals due to their Chempol® MPS Resins and Sefose® Sucrose Esters in their low-VOC Alkyd Paints and Coatings. Sefose® esters are prepared from vegetable oil by esterifying sucrose with fatty acids, without a solvent. Sefose® cross-links with other components in the paint and becomes part of the solution, allowing for fast drying, toughness, and high gloss. The positive effects of this technology are impressive; reduction of VOCs equivalent to 7,000,000 cars per year, ground-level ozone reduction by 215,000 tons per year and 900,000 barrels of crude oil saved. Even better, Sefose oil is safe to use, and extraordinary precautions are not needed. Since the award was given in 2009, the technology was developed to use Sefose Oils to replace petroleum-based lubricants at Proctor & Gamble, with in-house testing on small machines like drills and plans to test large machines like jackhammers.
While reducing VOCs is certainly crucial for making our climate greener, it usually isn’t the first thing that individuals imagine when they are thinking about climate change. The impact of transportation for climate change is enormous. Estimates place the number of motor vehicles on the planet at around 1.2 billion. Just 2.5% are battery electric, plug-in hybrid, or fuel cell vehicles. By some estimates the total number could double to 2.5 billion by 2050. With such a large amount of cars on the road and the vast majority of them being gasoline powered, that begs the question: what is there to do? Chemists have answered the call for developing cheaper methods to produce alternative fuels, to drive the market away from gas guzzlers and toward greener pastures.
One PGCCA winning company committed to alternative fuel is a small business named LS9, who was awarded an award in 2010 for Microbial Production of Renewable Petroleum Fuels and Chemicals. The company REG life sciences acquired LS9 in January 2014 and continue to use LS9’s technology. LS9 developed a microorganism that uses a sugar cane, corn syrup, sweet sorghum syrup, molasses, glycerin and biomass feedstock to manufacture a fuel that eliminates benzene, sulfur, and heavy metals commonly found in petroleum-based diesel. These organisms produce more than you’d expect; aside from the alkanes for use as diesel, jet fuel and gas, they can also produce olefins for lubricants and polymers, fatty alcohols for use as surfactants, aldehydes for insulation and resins, fatty acids for soaps and chemical intermediates and fatty esters for biodiesel and chemical intermediates all in a single-unit operation. This efficiency has led to a 85% reduction in greenhouse gases emissions according to the GREET model for life cycle analysis when compared to petroleum-based production. Since LS9 uses a one step process, no distillations or other methods are needed; the final process is immiscible and easily accessible with centrifugation.
Aside from microbes there are other ways to produce fuels, such as plants. Virent Energy Systems, a company based out of Madison, WI is making drop-in replacements for crude oil by transforming plant sugars into hydrocarbon molecules instead of refining petroleum with their BioForming technology. The fuel produced is identical to petroleum based molecules and can therefore be used in any manufacturing facility, pipelines and fueling stations, as well as current engines. Virent uses aqueous-phase reforming to treat carbohydrates destined to become fuel. The product of this process is then treated with water in the presence of a heterogeneous metal catalyst to make hydrogen and chemical intermediates. Finally, a catalytic route is selected to turn intermediates into gasoline, diesel or other fuels. The technology is flexible, and can produce alkane fuel gases and other end-products from a singular feedstock. Both C5 and C6 sugars from cellulosic biomass can be used as a feed stock. Distillation is not required as the biofuels naturally separate from water. The monetary advantage of Virent’s fuel makes the renewable technology viable: fuels have a 20-30% per British thermal units over ethanol. Virent’s fuel also has higher energy content than ethanol, with a higher octane rating and energy content that is higher than premium petroleum-derived gasoline. Virent received fuel registration from the EPA for its use in on-highway motor vehicles in August 2014.
Climate change is real, and is quickly changing our planet. The first step to solving the climate issue is to educate those who are unaware of the growing problem so that we can all collectively act together to fix our environment. Secondly, we need to change the perception that the chemical industry currently has. Corporations and society should take note of the example companies like Virent, REGLife Science, Proctor & Gamble and Sherwin-Williams have set and utilize green chemistry to cut costs and reduce environmental impact. Those that focus on eliminating environmental effects and toxicity before they are generated, rather than trying to clean up these hazards after they’ve been created are the wave of the future. Now more than ever it is of utmost importance to realize the impact that the chemical industry has on the climate of the earth, and the power it has to change the world for the better.
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