Research On The Prairie – Plastic From Plants

by Charles Good

Elementary school was a great time in my life. I walked the four blocks from our home in south central Pennsylvania to Lititz Elementary School with my mom and our yellow lab, Elsa. I played kickball and Four Square during recess. I performed in our school play. Through this blur of young excitement, learning and building, I remember a few key moments. One of them was my introduction to good storytelling.  I was in second grade, and my teacher, Mrs. Sitler, invited Mrs. Clarke (mother to one of my classmates) to perform for the class. While I don’t remember any of the stories she told, I remember the way she told them. Her voice had a distinctly deep timbre and her hands danced as she told us her stories. She came to our class for one year; the next year, there was no time for telling stories as the mountains of science, history, math, and language began piling up.

My time here in Fargo has been similar in many ways. Certainly, there has been so much to learn, to do, to experience. It’s been a blur of meeting new people, figuring out a new area, and learning how to cook. It’s been the training wheels for a hopeful research scientist. Most importantly, however, my experience has helped me tell a good story.

Like most stories, mine has a beginning. I’ve had the privilege of working in the Sibi Group under the direction of my fearless leader and Ph.D. hopeful, Eric Serum. I plugged into an existing project on the topic of biomass monomer synthesis. Essentially, I’ve been making the building blocks for polymers like plastics, polyurethanes, nylons, etc. using plant matter instead of petroleum as a starting material. Currently, about 96% of organic chemicals are made from petroleum (1). This is a real problem for three reasons: 1) fossil fuels are finite and are predicted to run out in the next few decades; 2) fossil fuel consumption leads to CO2 emissions, which continues to cause climate change; 3) fossil fuel resources are distributed unevenly throughout the world, which will continue to induce political tensions (2). Because organic chemicals are prolific in today’s industrial lifestyle, these issues are not trivial. In that vein, I am helping to developing alternatives to petroleum.

Currently, biomass is the only renewable resource that is large enough to do that (3). Furthermore, it has two important answers to petroleum: 1) biomass crops can be grown annually; 2) biomass is considered carbon neutral because the carbon dioxide emissions released during combustion are consumed during the growth of new crops (4). Of course, there are some drawbacks. Biomass is still more expensive than petroleum, and the ethical debate over food vs. fuel (is growing crops for fuel instead of food a good idea when so many are starving in this world?) rages on. Some crops, such as switchgrass and elephant grass, grow on marginal land while still remaining abundant sources of plant mass, which has helped ease this debate. Still, the benefits for biomass appear to be getting better with time.

The middle of my story involves actually working with the carboxylic acids that are derived from biomass resources. My goal was to make the nitrile, which can then be transformed to the amine, which is used to make polymers. Traditionally, amines are made from the amide using lithium aluminum hydride (LAH). However, LAH is pyrophoric (ignites on exposure to air), making it a highly dangerous chemical. LAH can be avoided by making the nitrile, then using a green method to form an amine.

There are well-known methods to make amides from carboxylic acids and nitriles from amides. At the beginning of the summer, the idea was to apply these methods to the new biomass carboxylic acids. There were two criteria that I followed: 1) the reactions remained relatively inexpensive so they could later be applied at a larger scale; 2) the chemicals had minimal environmental impact. Unfortunately, publications were much easier read than effectively implemented.

This is where my story in lab strays from the story that I’ll present at the Research Symposium. My story in lab was an almost utter failure. For example, it took me almost 7 weeks to make the amide. In the meantime, I explored many methods to make the nitrile from the amide, starting with a recently published method using a chemical called MSFTA. This process actually worked really well…unfortunately, MSTFA is really expensive. When the reaction makes about 1 gram of product, $30 of MSFTFA is used. Scalable? Not so much. Then I moved on to a reaction that looked fantastic on paper. Cost was low and the reagents remained relatively benign, but it only worked for one type of starting material and not the biomass material. So it was back to the drawing board after 7+ weeks. Instead of working with complex biomass starting materials, I explored converting 5 simple amides to nitriles using 4 established methods. That way, I could create a map of sorts to determine the most effective method to extrapolate to the complex biomass amides. With that map in hand, I applied the best way to make 2,5-furandicarbonitrile. This reaction is currently running.

The story I’ll tell at the Research Symposium might sound a little bit backwards from that of the lab. The beginning of my story will remain the same – how important biomass is for organic chemistry and the goal of avoiding LAH. However, my map will come next. I’ll talk about how my map led me to choose an appropriate method for making 2,5-furandicarbonitrile (among other chemicals). Then I’ll focus on the challenges of biomass – how they are different from the simple amides from the map. That’s it. Maybe I’ll gloss over how I finally managed to make those biomass amides after 7+ weeks, but likely, that would only be for someone who asks about that specific process. That’s because failure doesn’t make a great story.

Two weeks ago, I was in crisis mode because I didn’t have any results to put on my poster. It was then that I began to plan out what story I wanted to tell about my work this summer, and soon, I could see what blocks I needed to fill in. Now, my story has little successes. I did make nitriles from (some of) the simple amides, and I really improved on the process of making amides from biomass. My story is short and probably won’t be remembered by very many people. But I’ll always remember how it was crafted, how the pieces came together at the last minute. Maybe in my future as a scientist, my stories will be told over and over again to young and old alike. For now, I’ll remember Mrs. Clarke and my fantastic 10 weeks at NDSU.

3 Responses

  1. Charles Good

    References:

    1. J. Am. Chem. Soc., 2009, 131, 1979-1985
    2. Annu. Rev. Chem. Biomol. Eng., 2010, 1, 79-100
    3. Biomass for Renewable Energy. In Encyclopedia of Energy; Elsevier: New York, 2004
    4. ISJ. 2008, 110, 1-180

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