Tag Archives: GREEN CHEMISTRY

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Green Chemistry at Virginia Tech Part II

For my second interview in the Virginia Tech series, I had the privilege of interviewing Dr. Richard Turner. Like Dr. Long, he worked in the chemical industry and saw that most of the companies that practice green chemistry do so for regulatory and financial reasons. While working in the private sector Dr. Turner worked on plastics made without solvents – in ‘melt phase reactions.’ Melt phase processes eliminate energy consuming steps or the need to add something else to the waste stream.  They are inherently more environmentally friendly. They work by placing solids (which don’t react very fast) into solution so that the molecules can have the mobility to find each other and react.

In his own labs on campus, Dr. Turner has a few projects in melt phase rather than in solution as described above. His lab is also trying to make polymers that capture carbon dioxide. He describes:

“Carbon dioxide build-up in the atmosphere is going to be an increasingly large issue – we have to invest in the research now to learn how to capture and sequester the carbon dioxide. Polymer particles have huge surface areas, with ligands that can capture CO2. The sorbent (“a material used to absorb liquids or gases,” according to Wikipedia; yes, I had to look it up) and ligands capture CO2 and then moves it to reactor where it releases it, concentrating the CO2.”

Dr. Turner is also on the science advisory board of the company, Novomer, which was featured in a previous article on converting oranges to plastic. He works on biodegradability and reducing the overall energy footprint. “We have to make sure we do really tough and detailed analysis of our choices.”

In the classroom, Dr. Turner teaches a course called: “Future Industrial Professionals in Science and Engineering”. The course caters to scientists and engineers who want to go into industry. He divides the class into groups who run individual projects; this year all the projects were sustainability driven. There were three projects in total: the first worked to extend the shelf life of food; the second worked to improve battery life; the third worked to make a better membrane for reverse osmosis.

Outside of his own class, Dr. Turner was impressed with Tech’s sustainability. He discussed the accomplishments of the College of Natural Resources and the Environment, while also noting the strong Renewable Resources Group.

AGC applauds Dr. Turner’s hard work with sustainable chemistry, and hopes it serves as inspiration to other chemists.

 

Chemists build a better biodiesel process.

Thitsartarn, W, and S Kawi. 2011. An active and stable CaO-CeO2 catalyst for transesterification of oil to biodieselGreen Chemistry http://dx.doi.org/10.1039/c1gc15596b.

Synopsis by Wim Thielemans, Dec 20, 2011

Scientists in Singapore develop a new chemical catalyst with fewer drawbacks than current versions to help make biodiesel production more attractive and sustainable.

A modified version of a well-known but inefficient chemical catalyst can propel faster, cleaner reactions that turn plants into diesel fuel better than existing methods.The new calcium-based catalyst is more reactive, stable and easier to recover from the final product, the Singapore researchers report in the journal Green Chemistry. While the catalyst may solve a major stumbling block in the effort to produce biodiesel, the process will need more testing in industrial settings.

Biodiesel production is gaining in importance as petroleum supplies become more limited and concern about climate change grows. Biodiesel can be used in unmodified diesel engines. Its use results in near-zero carbon dioxide emissions, if estimates consider plant growth, which extracts carbon dioxide from the atmosphere.

Biodiesel is generally produced from plant oils. Plant oils are star-like molecules with three arms. To turn the plant oil into biodiesel, the three arms need to be removed from the center. The separated arms then form the biodiesel.

Unfortunately, this transformation does not happen readily without chemical help. Chemists must use other molecules, called catalysts, to speed up this reaction.

Current catalysts make the reaction go faster, but they have various drawbacks that hamper their use on the large scale of a commercial biodiesel process. These drawbacks include: large amounts of catalyst may be needed; high temperatures are necessary to propel the reactions; the catalyst may be less stable if it is used for a longer time; it can be difficult to remove the catalyst from the final product; and the solid catalysts may be slow to dissolve into the biodiesel product.

Calcium-based catalysts – which are cheap and abundant – can break up the star-like plant oils. Unfortunately, they dissolve into the biodiesel and removing them generates large amounts of wastewater.

To solve this problem, researchers from Singapore made a new and very reactive calcium-based catalyst with high stability. The catalyst was formed from a solution containing calcium and cerium – a metal found in a number of minerals. By making the solution less acidic, the catalyst precipitates out and is recovered by filtering and drying.

The ratio of calcium and cerium was varied to see which combination would give the best catalyst performance. Cerium alone does not work very well.

The best catalyst found could be reused up to 18 times with more than 90 percent of plant oils separated into their arms. Very low amounts of the catalyst dissolved into the biodiesel.

This work is certainly promising as it may make biodiesel production more sustainable and cheaper. Of course, the catalyst will need to be tested in an industrial process. Read more science at Environmental Health News.

 

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Green Chemistry at Virginia Tech Part I

Being a recent graduate of the University of Virginia, it is a little hard for me to write this article on all the innovation and leadership that is happening at Virginia Tech in the field of Green Chemistry (note: the two schools are notorious rivals). However, this is one topic on which I must concede: Tech just does it better.

To begin my series of Green Chemistry interviews with faculty and staff at Virginia Polytechnic Institute and State University (also known as Virginia Tech, VTech, and Tech), I interviewed Dr. Timothy Long. Dr. Long’s dedication to greener chemistry can be seen in both his teaching and in his research. I had the privileged opportunity to discuss his background, career at Tech, and plans for the future.

After receiving his PhD in chemistry, Dr. Long spent nine years in the chemical industry, where his passion for greener processes developed. He described: “they (industry) were very aware of green chemistry, motivated by economics and affordability.” Once exposed to this mentality, Dr. Long got passionate and wanted to see how to apply this mentality to his research and teaching. When he came to VTech twelve years ago he wanted a more sustainable way of doing things. He described: “I want to weave the principles of green chemistry into my teachings and research.”

A major contribution from Dr. Long’s lab is the more sustainable production of PSA (pressure sensitive adhesive used in many forms of tape and sticky notes). Previously, these compounds used petroleum-derived precursors that had terminal ester bonds. Dr. Long’s polyesters have that same ester bond but in the middle of the polymer. This structural change allows the compound to be made without solvent, while also allowing biodegradability. Killing two green chemistry birds with one stone.

Virginia Tech offers a course in green chemistry taught alternatively by Dr. Long and Dr. Etzkorn. It is a 4000 level class for undergraduates which caters to mainly to chemistry, biology, and business majors. Each semester the course has 45 students. The course takes an interdisciplinary approach to green chemistry as it integrates the science and concepts with society. It seeks to understand how chemistry is perceived in the wider community. While there is no green chemistry minor at Tech, the engineering school has a green engineering minor. Dr. Long also wants to make the green chemistry course mandatory for chemistry graduates. Currently he is submitting a proposal for a nanoscience degree at the University that would incorporate fundamentals of toxicology, essential for our upcoming chemists.

Dr. Long described the passion of Tech’s students to be more sustainable, commenting on their successful Earth Week each year and the increasing amounts of activity on campus. Tech is also hosting the World Polymer Conference next year – which is geared to making a more sustainable, healthy, and safer world.

AGC wishes Dr. Long success in all these ventures and applauds his success thus far.

Interview by: Mana Sassanpour, AGC

Pie Chart

Analysis of Green Chemistry publications over the past four years.

This figure is taken from Green chemistry: state of the art through an analysis of the literature by V. Dichiarante, D. Ravelli and A. Albini. Green Chemistry Letter and Reviews Vol. 3, No. 2, June 2010, 105-113.

 

As the label indicates, the pie chart shows a distribution of green chemistry topics as analyzed by articles produced in the year 2008. The majority of the pie chart (about 50%) is attributed to catalysis – or starting a reaction, under more favorable conditions that require less resources, whether those resources are heat, energy, reagents etc. Specifically, metal catalysts were the most cited catalysts used in many different reactions, specifically in those involving enzymes. Acids are also seen in this category, and according to the article, are used mainly in condensation reactions. The next largest section of the pie (about 40%) is attributed to media, or where/in what the reaction takes place. Many reactions require some liquid for a reaction to take place. Many of these liquids, especially in organic chemistry, are volatile or toxic compounds. As a result, most of the research done with green chemistry and the media of reactions use either no solvent, which allows for most reduction of waste. Water has also gained a prominent role in green chemistry literature as it is our universal solvent and usually can be recycled in a reaction. Ionic liquids are the third major media hit; they are liquids that have charged compounds in the solution to help guide a reaction. Ionic liquids are usually not volatile and are stored more easily compared to their organic counterparts. Finally, the last 10% of the pie chart goes to ‘new methods,’ or novel ways to do old reactions. Using microwaves to start and maintain a reaction is the most prominent method, followed by some research advances in photochemistry and ultrasounds, using light or sound respectively in reactions.

Making plastic: Use plants, not petroleum.

Miao, X, R Malacea, C Fischmeister, C Bruneau and PH Dixneuf. 2011. Ruthenium–alkylidene catalysed cross-metathesis of fatty acid derivatives with acrylonitrile and methyl acrylate: a key step toward long-chain bifunctional and amino acid compounds.Green Chemistry http://dx.doi.org/10.1039/c1gc15569e.

Synopsis by Audrey Moores, Dec 02, 2011

 

Researchers greatly improved the use of plant oil – instead of petroleum – as a raw material to produce high-end plastics resins.

Plant oil can be used instead of traditional oil from fossil fuels to produce highly desired specialty plastics called polyamides.

A study in the journal Green Chemistry describes how researchers in France identified the material – a metal called ruthenium – that makes this type of chemical reaction possible. This discovery expands the scope of using plant oil derivatives to make industrially-important molecules, such as those needed as starting materials for producing polyamides. Polyamides are a family of polymers with many useful applications, ranging from fibres – such as nylon – to highly resistant metal coatings. Polymers are large molecules composed of repeating units of a smaller molecule.

The bulk of plastics are made from fossil fuels. As oil supplies dwindle, there is a need to find novel, renewable sources of raw materials that can be used to make everyday products, such as plastics, detergents and drugs. Oil from plants can serve that purpose, and researchers are actively looking to use them.

In the study, researchers from Rennes proposed an improved method to turn plant oil products into high-end polymers, such as resin coatings to protect metal from corrosion. They selected two streams of renewable materials to achieve this discovery. On one end, they selected fatty acids – basically fat molecules – from castor oil gathered from the castor plant seed. On the other, they chose acrylonitrile – a compound easily accessible from glycerol, a waste product of biodiesel production.

The fatty acids and acrylonitrile are combined with an additive containing a metal called ruthenium. The specific reaction fused the acid and the nitrile part of the acrylonitrile together and created the precursors to known and novel types of polyamides. The reaction was highly efficient – much material was made for the amount of energy put in.

This reaction is difficult to perform in the laboratory because acrylonitrile tends to destroy the ruthenium additive. To overcome this obstacle, the chemists screened a large number of additives and reaction conditions – temperature, pressure, time – to find the way that provided high yields.

Researchers also made diester molecules, which are necessary in formulation processes. Formulation is the mixing of ingredients to form stable gels, creams or pastes for the cosmetic or detergent industry. This reaction is a very efficient way to access such molecules from renewable feedstock.

An often discussed problem of using plant oil to make molecules for manufacturing products is the competition between plants for food and plants for chemicals. One way around this dilemma is to reuse frying oil or get it from spent coffee beans. Another idea is to use oil from plants not used for food, such as oil from the castor plant that was used in this study.

This study proved that it is possible to use renewable feedstock to make complex molecules like polyamides. Industrial applications remain to be demonstrated, but the resarchers did optimize their chemical process with this in mind. Read more science at Environmental Health News.

 

Iron unlocks path to hydrogen fuel

Synopsis by Audrey Moores, Nov 21, 2011

Boddien, A, D Mellmann, F Gärtner, R Jackstell, H Junge, PJ Dyson, G Laurenczy, R Ludwig and M Beller. 2011. Efficient dehydrogenation of formic acid using an iron catalyst. Science 333(6050):1733-1736.

Researchers look to nature and use iron – instead of precious metals – to transform formic acid into hydrogen for use as a clean source of energy.

For decades, means of producing hydrogen fuel efficiently and without using traditional fossil fuels have eluded chemists and engineers. Yet some organisms sequester the element to fuel their life processes. Their secret lies in iron-based enzymes.

To mimic a hydrogen-based energy source for people, researchers from Germany and Switzerland successfully proved that iron can be a very efficient agent to generate hydrogen from formic acid. The simple and powerful system may have wide commercial appeal if researchers can determine why the system shuts down after just two-thirds of a day. The group’s results are published in the journal Science.

Hydrogen is a clean source of energy, with water as the sole combustion waste. Yet it provides a great deal of energy considering its low weight. That explains why it is highly attractive as a future source of clean energy. Much research is currently devoted to designing engines that can run on this fuel.

However, hydrogen is currently produced using energy from fossil fuels, which is a major hurdle to its development as a fuel. It can also be generated by splitting water into oxygen and hydrogen. Again, this reaction requires energy from traditional means, such as fossil fuels, nuclear power or hydroelectric power.

Formic acid is a promising starter material to generate hydrogen, as it is readily available from biomass –  plant or animal material usually collected through agriculture or forestry. Formic acid could also be used to store hydrogen, as it breaks down into hydrogen and carbon dioxide and can be made from these same two molecules. Attempts to harness formic acid have so far fallen short because processing it requires high temperature or additives.

The big problem is how to easily, efficiently and cleanly break apart formic acid to liberate the needed hydrogen. The researchers – inspired by organisms that do this naturally – found that switching out the precious metal catalysts used now with a simple compound based on iron and phosphorus can transform formic acid into hydrogen and carbon dioxide. No other by-products are produced.

The researchers combined formic acid, the iron-based compound and propylene carbonate, a green and non-toxic solvent. They tested the reaction in a realistic set up where the reaction was constantly fed with formic acid.

The reaction worked very well at normal temperatures. It was not affected by the presence of common impurities – such as water and air – typically found in formic acid supplies.

Hydrogen production was remarkably stable over 16 hours. After this time, water accumulated and deactivated the system. This difficulty will have to be overcome before the process can be used commercially.

The discovery means that chemists are a step closer to turning formic acid into hydrogen and carbon dioxide. This reaction would ideally happen inside the engine of a car fed with formic acid to allow the generated hydrogen to burn and power the car. The process will generate carbon dioxide, but since formic acid comes from biomass, the whole cycle would be carbon neutral.

This system is preliminary and will need to be elaborated upon and streamlined to meet commercialization requirements. But the system is very simple and powerful and may lead to humans using hydrogen as other organisms already do. Read more science at Environmental Health News.

 

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AGC at UVA

On Wednesday November 9, 2011 UVA Green Chemistry hosted AGC’s Mana Sassanpour for a lecture and discussion on “What is Green Chemistry?”

Mana gave an overview of green chemistry, Paul Anastas and John Warner’s 12 principles of green chemistry, followed by a description of Advancing Green Chemistry’s involvement in the field.

Mana: “The discussion that followed after the lecture was phenomenal! Almost everyone who attended the lecture asked a question. I had never seen such an involved group of students!”

We started off discussing endocrine disrupting chemicals, for example: bisphenol A (BPA). What exposure level is safe? Really large amounts are harmful, but so are really tiny amounts  – the correlation is not linear. We proceeded to discuss how we could test compounds for toxicity if the correlation is not linear. This led to a discussion on general methods for testing for toxicity, what the current standards are and how we could do better. We discussed the ethical concerns around animal testing and other tools.

The students were curious to find out what some of the common sources of BPA exposure are, and were surprised to find out that it is found in many disposable water bottles and plastic containers. A concerned student then asked for advice on how to avoid BPA. The response was: don’t use plastic food containers – but if you do, definitely do not microwave food in them because that allows the BPA and other contaminants to leach into your food. Store food in glass jars instead.

The ladies in the crowd then opened a discussion on cosmetics. Like many, they had never considered the chemicals in their beauty products. We talked about how many chapsticks and lip balms have oxybenzone in them – a component that acts as a sunscreen but is also a carcinogen. Most girls in the room immediately reached for their chapsticks to look at ingredients. A hand darted up to ask me “My chapstick has 6% oxybenzone – should I throw it away?” From this topic we went on to discuss how many sunscreen components do not degrade and go into our rivers and affect the reproductive anatomy of frogs and fish. This then led to how effects on amphibians predict effects on humans.

Needless to say, the conversation was great – filled with great facts, questions, and laughs!

Oranges to Plastic

Green Chemistry: Oranges to epoxide to polymer to plastic?

Lately we have been reading the green chemistry headlines about turning orange into plastic. But what does this really mean? What is the chemistry behind it? How does my orange peel become plastic? Read more for answers:

 

Step 1: Why oranges? Orange rinds have a ringed compound called limonene that gives citrus fruits their smell.

 

Above is the structure of limonene, courtesy of toxipedia.

 

Step 2: The limonene can be turned into an epoxide with the addition of an oxygen atom.

 

Above is the structure of limonene oxide, with the epoxide structure shown in red. Image courtesy of Santa Cruz Biotechnology.

 

The compound from step 2 is not very unstable since the epoxide structure (as seen in red) has angular strain and potential strain from sterics (having many components of a structure taking up the same space and being too close to one another). The epoxide creates bond angles that are not ideal as they are too small. The small bond angles are unstable and reactive – doing whatever they can to remove that strain.

 

Step 3: This is where carbon dioxide comes in. With the help of a zinc complex as a catalyst, the CO2 reacts with the epoxide structure to relieve the strain, allowing the epoxide to react with other epoxides to produce a polymer structure. This polymer structure is called polylimonene carbonate.

 

Step 4: Now we have a polymer (a compound with repeating units) which can be used to make plastic products through research and design. Currently there are no products on the market using this technology, but we hope to see that change in the near future!

 

Reaction is described as seen in JACS.

 

Brewing bioethanol in a single pot.

Synopsis by Wim Thielemans, Nov 01, 2011

Nakashima, K, K Yamaguchi, N Taniguchi, S Arai, R Yamada, S Katahira, N Ishida, C Ogino and A Kondo. 2011. Direct bioethanol production from cellulose by the combination of cellulase-displaying yeast and ionic liquid pretreatment. Green Chemistry http://dx.doi.org/10.1039/c1gc15688h.

An innovative process promises to produce bioethanol from plants in one step instead of three, but finding an easy way to purify the needed plant cellulose hinders its usefulness.

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A more efficient way to produce biofuels from plants is possible by pretreating the woody material with a liquid salt before fermentation, report researchers in Japan who perfected the process in the lab. Yet, coming up with the usable, purified cellulose remains a big hurdle to the industry.

This experimental method is unique because it pairs an enzyme-yeast unit with ionic liquids to convert the plants into the liquid fuel known as bioethanol. The successful trial yielded 90 percent ethanol and 82 percent of the ionic liquid was recovered.

The one-step, one-container procedure is outlined in the journal Green Chemistry.

Cellulose is the most abundant renewable material available. Plants, algae and some bacteria produce in excess of 100 billion metric tons per year. The non-food material is an agricultural waste material. The ability to turn the unwanted cellulose into liquid fuel would be an important step toward reducing dependence on crude oil without using food crops.

It takes three steps to convert cellulose into the liquid fuel bioethanol. Step one treats cellulose and turns its rigid and ordered structure into more chemically accessible pieces. In step two, enzymes further break down cellulose into glucose, a sugar. Then, in step three, microorganisms such as yeast ferment the glucose to ethanol.

The new process takes a different approach. The cellulose is broken down with ionic liquids (step 1) then converted into ethanol (steps 2 and 3) with a yeast-enzyme pairing – all in a single pot.

This is a remarkable step forward because the enzyme, yeast and ionic liquid are together but don’t interfere with one another.

Ionic liquids are salts – a designation for chemicals made up of both a positively and a negatively charged component – that are liquid at low temperatures, unlike common salts such as kitchen salt. Bulky positive and negative groups that make up the ionic salts hinder their packing into a solid crystal. Thus, they stay liquid to much lower temperatures – even room temperature. Some ionic liquids have been shown to be good solvents for cellulose, which is otherwise very difficult to dissolve.

In this study, the authors attached cellulase – an enzyme that breaks down cellulose – to the outside of the yeast. By itself, this yeast-cellulase combination is not very effective at tearing apart the rigid and inaccessible cellulose structure. But, a winning recipe was found by combining a small amount of specific ionic liquids with the cellulase-yeast. The ionic liquid disrupts cellulose enough so that ethanol can be produced directly and efficiently from the pieces of cellulose.

This work shows some real promise, but as the authors point out, most cellulose is not pure. To turn biomass directly into bioethanol, this new one-pot process will need to either extract cellulose efficiently or convert the other natural materials that coexist with cellulose in the plants. Read more science at Environmental Health News.

 

Warner Bacock Institute and Elm Street Ventures Launch ‘Occam Sciences’.

The Warner Babcock Institute for Green Chemistry and Elm Street Ventures Establish Occam Sciences to Develop and Commercialize Novel Forms of Existing Medicines
New Haven, CT and Wilmington, MA – The Warner Babcock Institute for Green Chemistry (WBI) and Elm Street Ventures (ESV) have announced today the formation of Occam Sciences in New Haven, CT to develop new forms of existing drugs with optimized bioavailabilty, including oral forms of medicines previously administrable only in a parenteral manner.
”We are delighted to join forces with WBI to develop new forms of already proven drugs that will offer important clinical benefits to patients”, said Rob Bettigole, Managing Partner of ESV. “Occam promises to be one of those rare start-ups that offers multiple bottom lines: better health for patients, improved environmental profile, profits for investors, and jobs for Connecticut and Massachusetts.”
WBI was cofounded in 2007 by Dr. John Warner, one of the founders of the field of Green Chemistry and co-author of Green Chemistry: Theory and Practice, a book that has revolutionized conventional wisdom across all industries touched by the chemical enterprise. Occam Sciences’ development efforts will utilize WBI’s proprietary non-covalent derivatization (NCD) technology to dial in selected physical properties for target drugs.
“We are pleased to have this opportunity to extend WBI’s NCD technology – already successfully commercialized in other industries – into the pharma realm”, said Joe Pont, CEO of WBI. “Our partnership with Elm Street Ventures is ideal given ESV’s deep network in both academic and industrial medical circles.”
Elm Street Ventures is a seed and early stage venture capital fund based in New Haven, Connecticut. An important part of ESV’s efforts is focused on creating and initially operating life sciences companies founded on intellectual property developed at Yale University and other research institutions in the New York City – New England region. Occam Sciences is ESV’s twelfth company. By providing management expertise and early stage capital, ESV catalyzes new company formation, working closely with scientists, engineers, and entrepreneurs to build significant technology companies. For more information, visit www.elmvc.com.
The Warner Babcock Institute for Green Chemistry provides innovation solutions and services across all markets and industries, from idea creation through commercial product optimization. WBI is committed to its clients, to society, and to the environment to create technologies and processes that are functional, cost-effective, and environmentally benign. For more information, please visit www.warnerbabcock.com.