Ammonia, you Toxic Chemical…

This blog post is written for Sciencegeist’s #ToxicCarnival

Ah Nitrogen (N2), thank you for helping me run my oxygen-sensitive reactions, you are 78% of the earth’s atmosphere, and when fixed you provide us with food. The last example that I am talking about is the Haber-Bosch process of taking inert N2 and converting it into reactive ammonia (NH3) that we put into fertilizer.

Fritz Haber and his synthetic process of fixing nitrogen is very relevant to our discussion of “toxic chemicals” because ultimately his process was discovered because Germany needed nitrates for making explosives during WWI.  Here is a great example of how a chemical and the ability to mass produce a chemical can be for good and bad. When asked about the duality of his discovery Haber said this:

“The interest of a wider circle has its source in the recognition that ammonia synthesis on a large scale represents a useful…way to satisfy an economic need. This practical usefulness was not the preconceived goal of my experiments. I was not in doubt that my laboratory work could furnish no more than a scientific statement of the foundations and a knowledge of the experimental equipment, and that much had to be added to this result in order to attain economic success on an industrial scale.”

Ammonia in fertilizer is one of the most important chemicals used today. The hydrogenation of nitrogen is catalyzed by a heterogeneous iron oxide catalyst at over 300 C and around 15 – 20 MPa.  This is a very energy intensive process using about 1.2% of the world’s energy. Yet, the massive production of ammonia through the Haber-Bosch process allows for the global food supply to keep up with the demands of human population growth. And in general, reactive forms of nitrogen not only provides the necessary nutrients for feeding the world, it is also responsible for providing us with the precursors for industrial goods such as cleaners, antiseptics, and nylon.

However we are beginning to see the detrimental effects to our environment such as ozone depletion in our excessive use of these reactive nitrogen reagents in fertilizer and the burning of fossil fuels. Yet, it is slightly more complicated than making overarching regulatory decisions to decrease reactive nitrogen use.  For example nitrogen that has leached into the ecosystem has enhanced plant growth in wetlands and riparian restoration and in turn account for substantial carbon sequestration and slowing of global warming. Another compounding factor of nitrogen management is that N2O slows decomposition and the release of CH4, but itself also contributes to the breakdown of the ozone. (reference)

So how can we better manage the nitrogen cycle? Nitrogen played a significant role during Haber’s lifetime and it is again an important element to understanding how we have changed its ecosystem, and make better decisions on how to manage it and take advantage of its benefits.

Further reading:
http://www.nature.com/scientificamerican/journal/v302/n2/full/scientificamerican0210-64.html
http://www.npr.org/programs/morning/features/2002/jul/fritzhaber/
Great plot of the production of ammonia over the last decade: http://en.wikipedia.org/wiki/Ammonia#Synthesis_and_production
http://www.nature.com/ngeo/journal/v1/n10/full/ngeo325.html

Carbon Dioxide as a Feedstock for Acrylic Acid Production

One of the largest sources of carbon, CO2, is emitted as a pollutant and is attributing to the rising climate temperatures. So then why are we not using CO2 as a feedstock? Well, for one thing is it very very difficult. CO2 is incredibly stable as it is a thermodynamic sink. Therefore, It requires even more energy to convert it into something else, and where does all of energy come from? Fossil fuels. Thereby generating even more CO2 to convert CO2 into something useful. But if we can find a means for converting or reducing CO2 into a commodity through a less energy intensive pathway, then there is potential to generate revenue from “waste” and reduce emissions.

Currently, the US generates 5,500 million metric tons/yr of CO2. Industries are currently capturing and using CO2, approximately 200 million metric tons/yr in the food industry and oil and gas industry, but a majority of this is released back into the atmosphere. Only about 0.5% of the CO2 that is captured is sequestered and not released.

We can think about carbon/CO2 utilization in two categories, 1.) carbon sequestration (burying in deep geological formations) and 2.) carbon as a useful feedstock. I am focusing on the second categories because investigations into into using CO2 as a freely available and abundant feedstock to develop commercial chemicals, plastics, and building materials has the potential to be an economically viable industry. Additionally, carbon sequestration has its limitations, and although it is being heavily federally funded, it’s large scale deployment has estimates in the range of $30-70/ton attributed to the new CO2 transmission lines that will need to be built. There are instances where CO2 cannot be transported to sequestration sites.

One of my favorite examples being investigated for CO2 utilization to generate commercial chemicals is the oxidative coupling of CO2 with ethylene to generate acrylic acid with molybdenum catalysts.  This is work done at Brown University in the lab of Dr. Bernskoetter.

Acrylic Acid

Acrylic acid is used heavily as the raw material for polymers, coatings and adhesives. Global production of acrylic acid is 3.4 million metric tons/yr and with 60% by weight CO2, that is over 2 million metric tons/yr of CO2 that could be resold and prevented from entering the atmosphere. The production of acrylic acid through a more economically viable method would be advantageous, so much so that Dow has begun similar efforts to generate acrylic acid through the generation of 3-hydroxypropionic acid with the use of a biocatalyst.  They claim that their process is 25% cheaper and 75% less greenhouse gas intensive.

The current process for acrylic acid production is the oxidation of propene and is incredibly energy intensive because it not only requires reaction temperatures of 200 – 300 C but also multiple distillations to remove impurities. Dr. Bernskoetter’s catalysts can oxidatively add CO2 and ethylene slightly above, if not close to, room temperature.  However, at the moment, the biggest challenge is the reductive elimination of the hydroxide to release acrylic acid from the metal.  But once that can be done, unlike the use of catalytic microbes, organometallic catalysts can more easily (and usually cheaply) be modified to improve upon turnover rates and efficiency.  I am especially excited and looking forward to Dr. Bernskoetter’s next publication on this catalyst.

Give Clean Tech A Chance

As disappointed as I am with the fate of Solyndra, what I am even more disappointed in is the public and media’s immediate response to take this example as the penultimate example as the Administration going about clean tech the wrong way. Wrong in that we are investing in it at all with “precious tax dollars”.We do not need this now. We already do not have the push we need to invest heavily in Clean Energy Technology so that it can be deployed widely as well as the incentives to fund research in these technologies that will make a difference and alleviate our dependence on oil.

I decided to add my blog to the plea/screams/challenge made in David Roberts’ great piece in Grist. What he said scares me:

“What Solyndra gives them is a symbol, something to use as a stand-in to discredit not just the DOE loan program, but all government support for clean energy and indeed clean energy itself.”

Seeing the relationship to “Climategate”, Roberts’ says this:

“This left the field entirely open to a massive attack from the right, coordinated among ideological media, staffers, lobbyists, and pols. When the left finally stirred itself to action, all that emerged were a bunch of long, boring investigations into the details and good-faith efforts to be fair about how both sides a point.”

So then I thought to myself then, why are we, clean energy and environment advocates, not louder! Here, I am adding my voice. Because this is important. We cannot stop these investments. (Granted, we should invest in a company that adapts, how can installing individual glass tubes be cost effective?! That’s another story. It was innovative, I might give them that.) But in order to avoid Solyndra to be the symbol of failed clean technology, I add my voice.  We cannot have that happen. Now, all of the the clean energy technology companies that the Administration has supported is being called into question. The media measuring their success based purely on job numbers and calling out the potential influences of campaign support of these other energy technologies.

I bring up this question, since just 2 months ago, we said “good-bye” to our space shuttle program: Did we not back the $200 billion investment in the space shuttle program?  We did. Adamantly.

There is always a risk with new technologies. For a program meant to make spaceflight cheap and frequent, there were 131 shuttle missions flown between 1982 – 2010 and two tragic disasters. And yet, the American taxpayers, after 30 years, are devastated by its end.

NASA Solar Dynamic Laboratory

Why can we not give Clean Energy the same chance? We became attached to space exploration and everyday use the materials and science that came out of the research to get us there. But why is it not the same for Clean Energy Technology? Do you not find it strange that we are not as attached to protecting our current home when we have not even found a new home yet?!
There still continues to be many many defendants of space exploration, and I am one of them, but why are the advocates of clean energy/alternative energies not as adamant?

“Both the American public and policymakers should recognize that spaceflight programs represent a “risky, expensive and long-term commitment,” Pielke said. He also emphasized the need to design programs with greater flexibility than the shuttle and station, so that the programs could evolve based on changing circumstances.”

Despite the risk and setback significant funds are going to research and in educating the next generation of engineers to take us to space. I don’t understand why there isn’t the same fight and same excitement in new energy technology. What is so different?

Many argue that the benefits of space flight that cannot be measured in dollars. I feel that this is the same for energy. How can you measure cleaner air and healthier people? An energy security in which we are not at war over resources that are limited? An economy that thrives due to new innovation.

Climate Change Data is Everywhere!

Yay! This is very cool, and props to Mathworks. I am working through the introductory materials for MatLab as I am working on adding computational skills to my already mad synthetic organic skills.  And Mathworks has some really really great tutorials for those with zero programming knowledge. But what I was pleasantly surprised about was that the example data provided to familiarize yourself with how to plot data in the program (and various other analysis skills), they use the data from the Climatic Research Unit for the temperature anomalies from 1850 – 2006 for the student to, in a sense, “discover” if in fact temperatures are rising. That is very awesome way to both teach programming and for students to begin to better understand the analysis of climate change data.

Average annual temperature. Data from the G-Econ project gecon.yale.edu/ Rendered using Matlab and PovRay.

Looking at Sea Salt from Space

Here is an introductory chemistry mantra: freezing point depression, boiling point elevation.

Tomorrow, NASA’s JPL will launch Aquarius, a satellite outfitted to collect sea surface salinity data. The salinity data will allow for us to gain a better understanding of the global water cycle, ocean circulation and the effects of these on our climate. Even with all of the routine ship and buoy observations, there is only salinity data for 24% of the ocean’s surface. This is a significant gap in our understanding of the ocean and the current models for ocean circulation. Recently, for World Ocean’s Day, there was a great guest blog post in Scientific American mentioning that perhaps the “Ocean Conveyor Belt”  picture for our understanding of heat flow in the ocean is an oversimplification. This concept has dominated the field of oceanography and what is exciting is that Aquarius has the potential to help researchers track processes such as precipitation, evaporation, ice melting, and river runoff that influence the global water cycle in order to develop better models.  Aquarius will provide sea salinity surface data for the entire Earth’s surface every 7 days. 

Salinity of the ocean may seem like a simple and obvious concept for many of us who have experienced the coast. But knowing salt concentrations to 0.2 g/kg (about 1 ppt) can reveal what salinity changes can disrupt ocean circulations. Drastic changes in salinity (ocean circulations) has the potential to lead to changes in the Earth’s climate. The dry regions of the ocean (more evaporation, less precipitation) are the regions of highest salinity. Creating and understadning patterns for future climate/precipitation conditions will be important for agriculture or the stability of ocean fronts for fisheries.

It is all connected. Pictured is an excellent demonstration done by Josh Willis at the JPLtweetup June 7, wherein he illustrates water’s ability to store heat. This ability to store heat effects the temperature of our oceans, which has a direct effect on salinity. And what happens in places with strong variations in salinity? Drastic changes in evaporation and precipitation from season-to-season. Which in turn impacts the global water cycle and ocean circulation.

Global warming is perhaps changing the way in which the ocean is adapting. And isn’t it fascinating that a simple compound like NaCl, with the help of a satellite can help us understand the connection between our climate and the ocean better?

*Edit (06/10/2011) Aquarius is about to launch (t-minus 15 min.) How exactly is Aquarius able to measure salt from space? Through microwave emissions! From an interview with Gary Lagerloef, Principle Investigator, just before the launch: Aquarius will measure the electrical conductivity (directly correlated to the salt concentration – greater the salt concentration, higher the electrical conductivity) which modulate the microwave emissions off the surface of the ocean.

**Edit (06/10/2011. 10:4o am) successful launch of Aquarius/SAC-D!

Plastic is not evil

We have all seen the pictures of coastlines littered with plastics bottles and bags and we also cringe at the thought that these materials will persist for many years after they are disposed.  However, it is also not reasonable to do away with plastics completely as their inexpensive production and ease of disposal are a staple to sterile environments such as hospitals.  Yet, these fleeting applications for polymers are not appropriate for their persistence in our environment. In the last decade the chemical community has been working on the development of biodegradable polymers that can degrade through chemical hydrolysis or enzymatic processes. The applications for such polymers are when they are soiled by food or other biological substances and cannot be recycled. The benefits of these polymers are that they are generated from renewable resources and then degrade into CO2, CH4, water, biomass, and other natural substances in a short amount of time.

Last week, a study, published in Environmental Science and Technology, carefully modeled the methane release of rapidly degrading polymers in landfills to gauge the benefits of biodegradable polymers. The researchers conclude that the polymer that they looked at (poly(3-hydroxybutyrate-co-3-hydroxyoctanoate (PHBO)) degraded and released a significant amount of methane too fast to be sufficiently captured by landfills with gas collection systems. Methane is a concern because like CO2 it is a greenhouse gas but is over 20 times more effective in trapping heat in the atmosphere. Their suggestion therefore were to develop biodegradable polymers that degraded slower to account for the delay in the gas collection systems to reach a critical concentration of GHG emissions to operate.

There are a couple of questions concerning this conclusion, as the authors only analyzed a single biodegradable polymer. There are other more common biodegradable polymers like poly(-e-caprolactone) PCL or poly(lactic acid) (PLA). PCL, in landfill reactors, degrades at a much slower rate than PHBO. Also there have been studies that have shown that biodegradable characteristics depend on the type of polymer and degradation conditions.

Although the authors of the paper do have a good point to have manufacturers of these types of polymers to consider the environmental impact of their products even after disposal. They put it best at the conclusion of their paper, I am paraphrasing: If the emissions for producing a biodegradable material is comparable to that of producing a material from petroleum-based feedstocks, and yet the disposal emissions is higher for the biodegradable materials, is it then a viable alternative?

But also this paper is a reminder for the need to create an infrastructure for biodegradable polymer disposal. Now that worldwide consumption of these types of polymers perhaps exceeds 68 million kg, we should worry about its disposal emissions. A possibility that was not considered in the paper was to analyze composting conditions for biodegradable polymers. A recent study in Korea compared the aerobic and anaerobic environments of poly(caprolactone) and poly(butylene succinate). They concluded that pretreatment technologies coupled with composting would be a means to decrease the waste of biodegradable polymers. This is important for them as the Korean government recently encouraged substituting biodegradable polymers for non-biodegradable polymers.

In addition to considering the disposal emissions of our materials, we should consider an infrastructure for disposal of biodegradable materials that would reduce or mitigate the emissions from these materials as they are an advantage because that do not persist in our environment and are made from non-petroleum-based (renewable) feedstocks.