Tag Archives: greener process

A switch to nature-based catalyst raises efficiency, reduces waste.

Largeron, M, and M-B Fleury. 2012. A biologically inspired Cu(I)/topaquinone-like co-catalytic system for the highly atom-economical aerobic oxidation of primary amines to imines. Angewandte Chemie http://dx.doi.org/10.1002/anie.201200587.

Synopsis by Jean-Philip Lumb, Aug 23, 2012

A multistep process to produce intermediary chemicals for manufacturing can be done in one step with only three ingredients and little to no waste, report French chemists. Their method combines a starter catalyst with a small amount of copper and oxygen from the air to transform base compounds – called amines – into other chemical middlemen – known as imines. Manufacturers use imines extensively to produce products and drugs.

In comparison to current methods, the novel process is more efficient. It uses fewer chemicals, relies on safer chemicals, creates less waste and works under normal temperature and pressure. Additional studies will need to repeat and optimize the methods before they can be used on an industrial scale.

A major direction in the field of green chemistry is to develop ways to turn one chemical into another with no leftover atoms – and therefore little to no waste. This increases chemical efficiency. Calculating the number of atoms that go into the process and comparing them to what comes out in the end product is a way to measure chemical efficiency. These reactions – dubbed atom economy – strive to have the two equal each other.

Atom economy is a big shift away from the traditional processes that rely on additives known as activating reagents, which are added multiple times during a chemical synthesis to propel the reactions forward. Efficiency is reduced, since in each step, the activating reagent is not incorporated into the product and is lost as waste.

This is particularly troubling when producing pharmaceuticals where multiple steps are required to transform starting materials into commercial products. In these cases, activating groups increase chemical waste, since activation often requires an additional step in the overall sequence and frequently creates equal amounts of a byproduct.

Activating reagents are usually needed for oxidation reactions, which are particularly important in chemical production. During oxidation, hydrogen is removed from its parent molecule and is added to another. The process is chemically inefficient because it creates an equal amount of chemical waste for each molecule that is oxidized.

Researchers are looking to plants and animals for natural ways to improve efficiency during oxidation reactions. One way is to replace activating reagents with catalysts. Biological systems are extremely efficient and routinely use catalysts in reactions where the chemical industry uses activating reagents. Unlike activating reagents, catalysts can be used in very small quantities. This would dramatically reduce chemical waste, since small quantities of catalysts affect a reaction and they can be frequently recovered after a reaction.

In this study, researchers in France have accomplished this by replicating the activity of an important class of enzymes known as copper-containing amine oxidases (CuAOs). These enzymes control the concentration of nitrogen-containing molecules in numerous biological settings, including in people. The enzymes drive the oxidation of an amine to an imine. By carefully modulating the reaction conditions, the authors were able to produce a variety of imines from readily available starting materials under very mild conditions. Water was the only byproduct.

The authors note the reactions will need more tweaking before they can be used industrially. Nevertheless, the reaction conditions go a long way toward alleviating the typical waste associated with amine oxidation and provide a promising direction for future research.

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“Don’t put that junk on your junk”


I recently said this to my favorite cyclist when discussing that he may not want to apply chamois cream containing parabens (the junk) to his junk. Male cyclists are repeatedly applying (maybe daily, for 5-7 hours at a time) these paraben containing creams to their reproductive parts. Research is showing that maybe they should reconsider.

 

You may see parabens listed as “methylparaben” “propylparaben” or “butylparaben” Etc.  Don’t let that fool you; these compounds are all structurally and functionally similar compounds, each just has an additional carbon group – the methyl, propyl, or butyl.

 

Parabens’ alias is alkyl hydroxy benzoate, not as easily recognizable, but still present on food and cosmetic labels. You can find these parabens in hair products, skin care products, or even your salad dressing! For male cyclists, they are in most creams that are applied to the groin area to alleviate chafing against the saddle of the bike.

 

Studies have shown that parabens can mimic the female sex hormone estrogen (Gomez et al 2005) and in turn can act as endocrine disruptors, inhibiting “testosterone (T)-induced transcriptional activity” (Chen et al 2007). Also, “exposure of post-weaning mammals to butyl paraben adversely affects the secretion of testosterone and the function of the male reproductive system.” Similar effects can be seen with propyl paraben (Oishi 2002).

 

What are other potential effects of this chemical on males? Recent research has shown parabens in association with  breast cancer, though causality has not yet been established (Khanna et al 2012).  This may seem irrelevant for men unless one considers the fact that breast cancer among men is actually on the rise.

 

Additionally, these chemicals may reduce male fertility. Butylparaben was shown in the lab to have an adverse effect on the male mouse reproductive system in that it damaged the late steps of spermatogenesis in the testis (Oishi 2002). Similar effects can be seen for other forms of parabens. They are also suspected of affecting the mitochondria in rat testes, reducing virility (Tavares et al 2008).

 

Male cyclists might want to look for anti-chafe chamois creams that do not contain parabens, such as creams containing lanolin, the oil in sheep’s wool. You can even make lanolin cream in your own home, following this recipe (but make sure the lanolin you use is high quality and pesticide free).

 

Alternatively, one can pay closer attention to the label on chamois cream to ensure that it does not contain parabens.

 

If you are a cyclist, know a cyclist, or love a cyclist, please share this with them.

 

By: Mana Sassanpour

 

Sources:

1. Antiandrogenic properties of parabens and other phenolic containing small molecules in personal care products. J. Chen, K.C. Ahn, N.A. Gee, S.J. Gee, B.D. Hammock, B.L. Lasley. Toxicology and Applied Pharmacology. Volume 221, Issue 3, 278–284, 2007.

 

2. Effects of propyl paraben on the male reproductive system. S. Oishi. Food and Chemical Toxicology. Volume 40, Issue 12, 1807 – 1815, 2002.

 

3. Estrogenic activity of cosmetic components in reporter cell lines: parabens, UV screens, and musks. E. Gomez, A. Pillon, H. Fenet, D. Rosain, M. J. Duchesne, J. C. Nicolas, P. Balaguer, C. Casellas. 
Journal of Toxicology and Environmental Health, Part A 
Vol. 68, Iss. 4, 2005.

 

4. Male breast carcinoma: increased awareness needed. J. White, O. Kearins, D. Dodwell, K. Horgan, A.M. Hanby, V. Speirs. Breast Cancer Research. Volume 13, Issue 5, 219, 2011.

 

5. Organ toxicity and mechanisms: effects of butyl paraben on the male reproductive system in mice. S. Oishi. Archives of Toxicology. Volume 76, Number 7, 423-429, 2002.

 

6. Parabens enable suspension growth of MCF-10A immortalized, non-transformed human breast epithelial cells. S Khanna and P.D. Darbre. Journal of Applied Toxicology. doi: 10.1002/jat.2753, 2012.

 

7. Parabens in male infertility—Is there a mitochondrial connection? R.S. Tavares, F.C. Martins, P.J. Oliveira, J. Ramalho-Santosa, F.P. Peixoto. Reproductive Toxicology. Volume 27, Issue 1, 1-7, 2009.

Silver speeds chemical reactions with oxygen.

Huang, Z,  X Gu, Q Cao, P Hu, J Hao, J Li and X Tang. 2012. Catalytically active single-atom sites fabricated from silver particles. Angewandte Chemie http://dx.doi.org/10.1002/anie.201109065.

Synopsis by Marty Mulvihill

In a new study, researchers report using silver in a safer, cheaper, cleaner method to run chemical reactions – specifically the widely-used and universally-important oxidation reactions. The new system works at low temperatures and is 10 times more efficient than previous attempts.

In the quest to save money and prevent waste when making chemicals for industrial and consumer applications, laboratory chemists are looking to a new generation of catalysts to speed up reactions with less mess. Catalysts are added to chemical reactions to help efficiently transform raw materials into products.

In a recent advance, researchers report how silver – placed in a specific pattern on a stable molecular nanostructure – can act as a catalyst and promote reactions at low temperatures using safe and abundant materials like oxygen in the reaction.

The new system is 10 times more efficient than previous attempts. It not only conserves resources, but it will help researchers better understand how to use oxygen in industrial applications.

The silver-based catalyst converts oxygen from the air into a chemically reactive form that allows common industrial chemicals to be made more efficiently. The products of these reactions are the starting materials for a majority of chemical products.

Unlike previous catalysts that promote chemical reactions with oxygen, this silver-based model performs very well at low temperatures. Temperature is a key consideration. Lower temperatures reduce the amount of energy and potentially the cost of running these important reactions.

The new catalyst created by researchers in China represents a 10-fold improvement over previous methods for making these chemical products.

Catalysts increase the speed of chemical reactions. Yet they are not affected in the process. This allows catalysts to be reused and has helped expand their use in a wide range of manufacturing applications.

In addition to working at low temperatures, the catalyst uses oxygen as the only additional reactant. Traditionally oxidation reactions have used harsh chemicals and generated large quantities of hazardous waste. In this reaction the oxygen is incorporated into the product without producing any additional waste.

The results will help chemists understand how to better activate oxygen. Oxygen is often slow to react with other molecules because the molecule is very stable. It is usually found as two atoms paired together, hence its chemical nickname O2. These pairs must be broken apart before the individual oxygen atoms can react with other chemicals.

The new catalyst breaks the oxygen atoms apart. It uses individual silver atoms located near a surface that does not have oxygen as part of its molecular structure.

Using advanced chemical analysis tools, the scientists precisely characterized and explained the reactivity of the silver atoms that are attached to the surface of manganese oxide particle support. They verified the structure of their active catalyst with advanced microscopy and X-ray scattering techniques.

The catalyst is only in the development stages. Before it is ready for use in the chemical industry, chemists will need to show that it can perform oxidation reactions cheaply on a wide range of organic molecules. Read more science at Environmental Health News.

green bubbles beakers

Making Safer Products: A Chemical Design Protocol for Chemists

AGC session at Green Chemistry & Engineering Conference 2012 

Tuesday, June 19, 3:20 –  5:20 / McKinley Room

 

Using Scientific Findings From the Environmental Health Sciences to Avoid Endocrine Disruption in the Chemical Design Process

Pete Myers, Environmental Health Sciences

Karen Peabody O’Brien, Advancing Green Chemistry

A central goal of green chemistry is to avoid hazard in the design of new chemicals. This objective is best achieved when information about a chemical’s potential hazardous effects is obtained as early in the design process as feasible. Endocrine disruption is a hazard that to date has been inadequately addressed by both industrial and regulatory science. To aid green chemists in avoiding this hazard, we propose an endocrine disruption testing protocol for use by green chemists in the design of new materials.

Endocrine Disrupting Chemicals – Principles of Endocrinology for Chemical Design and Public Health Protection.

R. Thomas Zoeller, Department of Biology, University of Massachusetts, Amherst

Epidemiological and experimental studies continue to show adverse effects of endocrine disrupting chemicals (EDCs) from exposure levels far below what risk assessments indicate are safe. Because EDCs interfere with hormone action, it is essential to design experiments and interpret their results in terms of the very large literature that informs us about the role of endocrine systems in health and disease. Principles of endocrinology important to this field include hormone-receptor interactions, the spatial and temporal characteristics of hormone action in relation to development and adult health, and the regulatory circuits that control delivery of hormones to the proper targets at the proper time. These principles should inform basic research and regulatory science as well as to guide chemists in the design of safe chemical products.

The Relationships Between Exposures to Endocrine Disrupting Chemicals and Adverse Human Health Effects.

Laura N. Vandenberg,

 Department of Biology and the Center for Regenerative and Developmental Biology, Tufts University

A growing number of studies overwhelmingly suggest that environmentally relevant doses of EDCs influence human health and disease. Hundreds of human and animal studies challenge traditional concepts in toxicology, in particular the dogma that “the dose makes the poison”, because EDCs can have effects at low doses that are not predicted by effects at higher doses.  Additionally, a large body of evidence indicates that hormones and EDCs produce non-monotonic dose responses (NMDRs), defined as non-linear relationships between dose and effect where the slope of the curve changes sign within the range of doses examined. These data indicate that the effects of low doses cannot be predicted by high dose studies. Thus, fundamental changes in how chemicals are tested are needed to protect human health.

Researchers close in on making a natural malaria drug.

Westfall, PJ, DJ Pitera, JR Lenihan, D Eng, FX Woolard, R Regentin, T Horning, H Tsuruta, DJ Melis, A Owens, S Fickes, D Diola, KR Benjamin, JD Keasling, MD Leavell, DJ McPhee, NS Renninger, JD Newman and CJ Paddon. 2012. Production of amorphadiene in yeast, and its conversion to dihydroartemisinic acid, precursor to the antimalarial agent artemisinin. Proceedings of the National Academy of Sciences http://dx.doi.org/10.1073/pnas.1110740109.

Synopsis by Jean-Philip Lumb

A new approach to making the natural malaria drug artemisinin will increase supply and avoid the chemical steps now used to extract the drug from plants. The drug is meant to replace medicines that no longer control the malaria parasite spread by mosquitoes.

An affordable treatment for malaria is closer thanks to a process using both biology and chemistry to make artemisinin – an effective drug currently extracted from plants.

The method bypasses plants as the source of the drug. Instead, modified yeast change sugar into an advanced chemical that can be converted into artemisinin. Skirting plants decreases the cost, increases supply and avoids chemical extractions. A team of industrial and academic researchers in Berkeley, Calif., developed the biochemical route to the drug.

The process provides an alternative to traditional extractive procedures and highlights the increasing use of biotechnology in greener drug manufacturing.

Globally, the mosquito-borne infectious disease claims nearly 1 million lives per year. Health organizations estimate that 300 – 500 million people are infected on an annual basis, a population based primarily of children in Africa and Asia.

New medicines are needed because the current drugs do not work as well as they once did and controlling mosquitoes with insecticides – such as DDT – can harm the environment and human health.

Artemisinin is a desirable substitute to the widely used chloroquine-based antimalarial drugs. The Plasmodium parasite that causes malaria has become resistant to these traditional drugs.

While faster acting and more effective, artemisinin is expensive and supplies are often limited. Artemisinin is currently extracted from plants. Unfortunately, the extraction makes large-scale production too costly for countries where the drug is needed most. The methods also employ volatile organic solvents that levy a heavy environmental toll.

To overcome the current limitations in supply, a consortium of industry and academic researchers in California developed a new strain of yeast that can convert glucose into an artemisinin precursor. Standard organic chemistry practices are used for the remaining steps of the drug’s synthesis.

The combined biotechnology/synthetic chemistry approach promises to be an effective alternative to the extraction techniques currently in use. The cost is estimated as low as 300 million cures at 50 cents a treatment. A recent press-release, issued on the Amyris website, announced a partnership between Amyris, The Institute for OneWorld Health and Sanofi-Aventis to make doses of artemisinin available later this year.

Read more science at Environmental Health News.

Safer anti-coagulants: Kicking out the pig.

Synopsis by Audrey Moores and Wendy Hessler, Feb 29, 2012

2011-1221pigs

An approach combining chemistry and biology improves the process to make important anti-clotting drugs known as heparins. The heparin medicines prevent dangerous blood clots from forming in veins and are needed for surgery and kidney dialysis.

The technique provides easier access to safer drugs that are now either processed from pigs and cows or synthesized in a long, costly lab process. The novel method described in the journal Science provides a realistic alternative to livestock for heparins and is likely to drop the cost of such pharmaceuticals.

The process is not yet ready for large-scale commercial use, but its product yields are impressive.

 

Context

Many pharmaceutical drugs are processed from plants or animals rather than made in a laboratory. While such a strategy may seem more natural, animal-sourced drugs are susceptible to contamination.

Heparins are a family of drugs used for more than 50 years to prevent blood clots in people. These complex molecules come from three main sources. They can be collected from pig intestines or cow lungs, synthesized in a laboratory or collected from animals and then modified in a lab.

The sizes and uses of the three types vary. The animal-sourced drug is the largest. It degrades rapidly in the body and is used for kidney dialysis and surgery. The chemically-altered animal heparin and the synthetic varieties are smaller, longer-lived molecules. Patients with venous thrombosis – the tendency for blood clots to form in veins – take these to prevent the clots.

Safety is an issue with the animal-sourced heparin, the cheapest and most accessible available. In 2007, drug contamination resulted in at least 200 deaths in the United States and raised concerns over the source of heparin.

GlaxoSmithKline synthesizes the smaller-sized heparin under the brand name Arixtra. Their process requires about 50 steps and yields very low amounts of material– around 0.1 percent. As a consequence, this molecule cannot currently replace animal-based heparins for all applications because of its high price.

The risk of contamination and current cost of synthesizing heparin is driving the quest to find a more efficient and cheaper way to make heparin drugs.

 

What did they do?

A team of chemists from the United States applied a strategy called chemoenzymatic synthesis to fabricate the heparin molecule. The method borrows from both chemistry and biology fields.It is an attractive way to synthesize heparin medicines. The drug contamination in 2007 occurred because the heparin collected from animals had an unusual chemical structure. People became allergic and hypersensitive. These side-effects would be avoided using a chemoenzymatic system because the series of chemical and enzymatic reactions needed to produce the drug are much better controlled than those in the animal gut where many proteins can alter the drug-to-be molecule.

In this study, the researchers mimicked the process animals use to make heparins. They chemically synthesized a starting material then added enzymes that lengthened and built the whole heparin molecule. In other words, they transferred what happens in the pig gut into a beaker. This approach is superior to collecting directly from an animal because the reactions are controlled.

To see if the manufactured drugs were effective, the researchers tested them in two different ways in the lab. First, they put them with two key proteins responsible for coagulating blood. Then, they injected rabbits with them and collected the animal blood. The interactions with the proteins alone in a culture and in the blood from the rabbit were measured and compared with the activity of the commercial heparin Arixtra.

 

What did they find?

The researchers discovered they could produce two heparin molecules with the impressive yield of 45 and 37 percent, in 10 and 12 steps respectively. They were able to make several milligrams of the product.

The two newly synthesized heparin molecules were similar in size to as the current Arixtra drug. They also proved as active as Arixtra. The efficacy of the interaction between the drugs and coagulating proteins were similar to Arixtra.

The same was true when the newly developed heparins were tested with rabbits. The drugs interacted with the same proteins as Arixtra.

 

What does it mean?

A more streamlined method to make anti-coagulant drugs may provide a realistic alternative to the animal-sourced pharmaceuticals, which are susceptible to contamination. The new process also produces more heparin product in shorter time and for less money than current synthetic preparations.

This means that the newly made heparins could be used in a wider range of applications than the current synthetic heparin Arixtra, because the reduced cost may open new markets.

This technique isolated 3.5 milligrams of heparin. The obvious next step will be to scale up this process to demonstrate that it is commercially feasible. It is estimated that 10 to 20 tons of heparin drugs are sold every year in the world.

The new drugs must also be tested and properly certified before they can be used commercially. However, the preliminary results of this research effort show that these two heparin molecules should be active anti-coagulant drugs with similar properties as the most popular synthetic version on the market today.

The type of synthesis – which merges chemistry techniques and biological enzyme actions – profiled here may be transferable to the manufacture of other drugs. Read more science at Environmental Health News.

M7500614-Ginkgo_in_medicine-SPL

Chemistry of Ginkgo

By Mana Sassanpour, 1/26/2011

After reading a book that mentioned the health benefits of ginkgo (leaf pictured right), I decided to see if there were any green chemistry related topics that involved this ancient and revered tree. The journal, Green Chemistry,  has an article about a more efficient means of extracting the useful components of ginkgo (Qingyong Lang and Chien M. Wai Green Chem., 2003, 5, 415-420). The researchers developed a greener method of pressurized water extraction which is a “a more effective, selective, economical and environmentally benign technique.”

However, the article did not make clear WHY they were bothering to finding greener ways to extract these compounds – what does ginkgo do? I could pay £34 GBP ($52.50) to find out why, but I thought doing my own investigation would be more fun and less costly.

My research took me in several directions, including the Encyclopedia of Medicinal Plants by Andrew Chevallier, Rebecca’s Natural Food Store in Charlottesville, VA, and to a friend, John Soong, who knows a little something about everything.

First, some history: the ginkgo tree dates back about 200 million years to the time of the dinosaurs.  Second, my friend John Soong explained that he had grown up eating ginkgo nuts in a rice porridge called congee (left). According to him, the philosophy behind eating ginkgo in Chinese cuisine is that “because the ginkgo tree has survived and lived for so long, if we eat it we will have the same longevity.”

There may be some science behind this belief: the active ingredients in ginkgo are purported to work together to produce a positive effect on the human body. The key ingredients are flavonoids, ginkgolide, and bilobalides. The Encyclopedia claims that ginkgo “improves circulation of blood to the head” which in turn leads to improved memory and is given to people with dementia. Ginkgo is also good for asthma and as an anti-inflammatory. Therefore it is not surprising that ginkgo has been noted as one of the bestselling medicines in Germany.

After my literature search, I drove to Rebecca’s Natural Food Store where one of the employees gave me an impromptu “Ginkgo 101” course. She explained that ginkgo is also a blood thinner and can help reduce the possibility of a stroke. In addition, she said it is “good for capillaries and oxygen uptake especially for those who always have cold hands and feet.” Hmmm: maybe I should start taking ginkgo?

Of course we are not qualified to make judgments or give advice on the medicinal value of ginkgo, but it seems like ginkgo is a very interesting plant. With such a wide array of potential health applications and valuable compounds, it makes sense to find more sustainable and cost effective methods of extraction.

 

References:

1. Pressurized water extraction (PWE) of terpene trilactones from Ginkgo biloba leaves. Qingyong Lang and Chien M. Wai. Green Chem., 2003, 5, 415-420. DOI: 10.1039/B300496C

2. Encyclopedia of Medicinal Plants. By Andrew Chevallier – DK Pub. (1996) – Hardback – 336 pages – ISBN 0789410672


 

Etzkorn solo photo

Green Chemistry at Virginia Tech Part III

For my third and final interview in the Virginia Tech series, I had the privilege of interviewing Dr. Felicia Etzkorn (pictured left), pioneer of the green chemistry course at Virginia Tech. The green chemistry course was her idea back in 2003. She and her colleague, Dr. Tim Long, decided to team-teach it just for fun. A couple of years later Dr. Etzkorn decided she was going to approach it more seriously. As a result, she had to write a course proposal for Virginia Tech’s course catalogue. The course was approved by three different curriculum committee levels. Afterwards, she developed course material and lectures, and taught the class for three years, from 2007 – 2009. She is excited to be teaching it again this Spring 2012.

 

Dr. Etzkorn also applies her passion for green chemistry to the local Blacksburg community. She designed a green science experiment for middle school students. Under the program, she brings the students into one of the labs at Virginia Tech to let them make their own polymer of lactic acid. The procedure allows them to make polylactic acid derived from soybeans, similar to a process used for biodegradable plastic containers for salads.

 

 

The students got a chance to come to Tech and get to do the experiment using solvent free polymerization and a non-toxic catalyst. First they had to stir and heat the mixture to get the polymer following lab procedures. Then the students made small toys by pouring polymer into clay molds they made in art class (pictured right – the brown items: shells, lips et.c are the PLA polymer, the grey figures are clay molds.). Since it does biodegrade the students were even encouraged to compost it. They were really enthusiastic about green chemistry.

 

 

Dr. Etzkorn also studies neural tube defects in mice with Dr. Hrubec, her collaborator. In the experiments, the control mice start getting neural tube disorder at a shocking rate of 20%, leading to many control experiments to see what was causing it. One suspect turned out to be from our every day tap water: epilepsy and bipolar disorder medication Cardamazepine. Dr. Etzkorn explains: “We cannot get any water that doesn’t have it to some extent and the mice are very sensitive to these agents.” The second suspect is a quaternary ammonium compound used to sanitize the lab. More experiments have yet to be conducted to determine the culprit.

 

AGC congratulates the diverse work that Dr. Etzkorn does with green chemistry and environmental health sciences and wishes her success in the future.

 

turner

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.