Archive | September 2011

ROMPing around the Carnival

Here is my contribution to Chemical and Engineering News’ “my favorite chemical reaction” blog carnival! I call it the “popcorn-stringing” reaction. Because, of course, one needs popcorn when at the Carnival!ROMP stands for Ring-Opening Metathesis Polymerization. The popcorn stringing analogy comes from the cyclic momomer being popped open and then, through bond metathesis, the molecules are strung together to make a polymer. The release of the ring strain is the driving force for the polymerization.

Kernels are the monomers that are popped open into popcorn that can be stringed together! The catalyst drawn is Grubbs' 2nd generation catalyst.

ROMP is a fascinating reaction for many reasons, one of which is of the range of metal complexes that can be used to carry out the reaction; including tungsten, molybdenum, rhenium, ruthenium and titanium carbenes. The most interesting developments in ROMP catalysts are those that can carry out living polymerizations*. These types of polymerizations can lead to polymers with a variety of sequences (copolymers) without sacrificing precise control of the material’s dimensions that, in turn, lead to a wider range of properties and applications.  Also, in terms of sustainable chemistry, these catalyst can lead to greener processing routesby improving efficiency and saving on atom economy (having every reagent used count).

The polymers that can be synthesized through ROMP have a lot of industrial applications. One of the most famous is Norsorex, or polynorbornene, which is a shock-absorbing materialused in protective equipment, sound insulation, and vibrational damping. Through a single monomer, ROMP can access structures normally difficult copolymerize with individual monomers.  One example is a perfectly alternating copolymer of 1,4-butadiene and isoprene.

perfectly alternating copolymer of 1,4-butadiene and isoprene from an octadiene

As with any other chemical reaction, there are limitations.  ROMP’s limitation is that the monomers must be cyclic and possess sufficient ring strain.  Although it might be difficult to synthesize momomers with these desired attributes, it is possible to derivatize naturally existing materials. Last year, the Larock group developed biorenewable-based thermosets from the ring-opening metathesis polymerization (ROMP) of fatty alcohols derived from soybean oil and castor oil.#  Of course, this work illustrated the robustness and versatility of Grubbs’ catalyst (like so many papers), but what is key is that it also highlighted the substantial role that metathesis catalysts can have in the development of polymers from biorenewable feedstocks as the pressures of traditional petroleum-derived feedstocks grows.

Well, that is a great place to end.  The thought about using renewable feedstocks not just for energy but also for carrying out chemistry is an important direction to consider.  Actually, a reaction very similar to ROMP that I have not expanded is, ROP (Ring-Opening Polymerization) and that polymerization is responsible for the material in biodegradable “corn pens”(polylactic acid).

lactic acid (monomer) can be derived from corn

ROP reactions are carried out by different types of catalyst than mentioned above, but same general idea of ring strain (lactic acid) as the driving force for the reaction.
Now, when you think of corn or popcorn, in addition to potential sources of renewable energy, I hope you will also think about ring-opening polymerizations.
Definitely time for me to go make some popcorn.
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*Living Polymerizations are polymerizations that satisfy the following three criteria:
1. Polymers have a narrow mass distribution. Meaning that the Gaussian distribution curve of polymer lengths is narrow indicating that a majority of the polymers are similar in length.
2. No premature chain termination. This helps to achieve the first point. If the growth of the polymer chains are cut off at different times then there will be a wider distribution of polymer lengths. This point also allows us to build copolymers. Once all of the first monomer is consumed and a second monomer is added, the polymerization continues adding in the second monomer.
3. All the chains start fast and at the same time.
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Image credits!

Popcorn PoppingPopcornPopcorn String

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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.

Solar Dynamic Laboratory - final launch preparations underway

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.

The best way to set off a fire alarm

And not get in trouble.Here is the story of when I knew I would be a chemist.This is the story I should have told when asked to give a lightning talk. Although, the discovery of the Ziegler-Natta catalyst is a good story, 180 seconds is not quite enough time to give a room of non-chemists enough background to fully appreciate the wonder and significance of the story.But here is a story that serves both as a means to better know me, as well as perhaps encourage others to become scientists.This is especially important as more questions arise about how to increase the number of women in the sciences. Many women have indicated that they realize their passion for science early on, and along that line of encouragement is a project to collect stories of successful women scientist, so this is just as short antidote to increase that growing pile.It is a very simple experiment done often in high school chemistry courses. It only requires placing some magnesium turnings in a crucible, lighting the Bunsen burner and placing it underneath the crucible.

What does not often happen is the crucible exploding.

It was not a large amount of magnesium, so it was pretty much contained. Just a very loud pop. (I did not get hurt, and luckily everyone was safe.)

However, it was enough of an surprise to set off the fire alarm and quite possibly release of all of the adrenaline that I had stored up in my glands.

And so in one of my first chemistry courses ever, I evacuated my entire high school. And made them all stand outside for the entire period as it was not a scheduled fire alarm, nor was it a simple prank pull. And I did not go to a small high school. It was over 2000 students.

Many of my friends were taking an exam in American History.  It was postponed to the next week as a result of my experiment. They very much appreciated my work.

The accumulation of the excitement, investigating a unique occurrence (there was a crack in the crucible), and the acceptance of my peers all in one small event is what hooked me. I somehow must have known that one has the opportunity to study conservation of energy in a controlled manner though bomb calorimeters.

* I know that HS experiments can go very wrong and am thankful now for the insight and attention to safety my teacher had. It is very tragic when a teacher is not so careful as evidenced here and here

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.World temperatures