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TiPED circle 200

A New Tool to Design Safer Products

   New publication:  A New System to Assess New Chemicals for Endocrine Disruption

    A groundbreaking new paper outlines a safety testing system that helps chemists design inherently safer chemicals and processes.       Resulting from a cross-disciplinary collaboration among scientists, the innovative “TiPED” testing system (Tiered Protocol for Endocrine  Disruption) provides information for making chemicals and consumer products safer. TiPED can be applied at different phases of the chemical design process, and can steer companies away from inadvertently creating harmful products, and thus avoid adding another BPA or DDT to commerce.

    The study, “Designing Endocrine Disruption Out of the Next Generation of Chemicals,” is online in the Royal Society of Chemistry journal Green Chemistry.

    The 23 authors are biologists, green chemists and others from North America and Europe who say that recent product recalls and bans reveal that neither product manufacturers nor the government have adequate tools for dealing with endocrine disrupting chemicals (EDCs).  EDCs are chemicals commonly used in consumer products that can mimic hormones and lead to a host of modern day health epidemics including cancers, learning disabilities and immune system disorders. The authors conclude that as our understanding of the threat to human health grows, the need for an effective testing strategy for endocrine disrupting chemicals becomes imperative.

Historically, chemists have aimed to make products that are effective and economical. Considering toxicity when designing new chemicals has not been their responsibility. This collaboration between fields expands the scope of both biologists and chemists to lead to a way to design safer chemicals.

Scientific understanding of endocrine disruption has developed rapidly over the past 2 decades, providing detailed, mechanistic insights into the inherent hazards of chemicals.  TiPED uses these insights to guide chemical design toward safer materials.  And as consumers are increasingly concerned about endocrine disruption (eg BPA, flame retardants) they are demanding products that do not contain EDCs, creating a market opportunity for companies that can take advantage of the new science.

There is a companion website to the paper, www.TiPEDinfo.com. One can access the paper there and learn more about the TiPED system.

 

New Tools to Design Safer Chemicals

PRESS RELEASE: “A New tool to design safer products”

New publication:  A New System to Assess New Chemicals for Endocrine Disruption

A groundbreaking new paper outlines a safety testing system that helps chemists design inherently safer chemicals and processes. Resulting from a cross-disciplinary collaboration among scientists, the innovative “TiPED” testing system (Tiered Protocol for Endocrine Disruption) provides information for making chemicals and consumer products safer. TiPED can be applied at different phases of the chemical design process, and can steer companies away from inadvertently creating harmful products, and thus avoid adding another BPA or DDT to commerce.

The study, “Designing Endocrine Disruption Out of the Next Generation of Chemicals,” is online in the Royal Society of Chemistry journal Green Chemistry.

The 23 authors are biologists, green chemists and others from North America and Europe who say that recent product recalls and bans reveal that neither product manufacturers nor the government have adequate tools for dealing with endocrine disrupting chemicals (EDCs).  EDCs are chemicals commonly used in consumer products that can mimic hormones and lead to a host of modern day health epidemics including cancers, learning disabilities and immune system disorders. The authors conclude that as our understanding of the threat to human health grows, the need for an effective testing strategy for endocrine disrupting chemicals becomes imperative.

Historically, chemists have aimed to make products that are effective and economical. Considering toxicity when designing new chemicals has not been their responsibility. This collaboration between fields expands the scope of both biologists and chemists to lead to a way to design safer chemicals.

Scientific understanding of endocrine disruption has developed rapidly over the past 2 decades, providing detailed, mechanistic insights into the inherent hazards of chemicals.  TiPED uses these insights to guide chemical design toward safer materials.  And as consumers are increasingly concerned about endocrine disruption (eg BPA, flame retardants) they are demanding products that do not contain EDCs, creating a market opportunity for companies that can take advantage of the new science.

There is a companion website to the paper, www.TiPEDinfo.com. One can access the paper there and learn more about the TiPED system.

 

 

No more butts: biodegradable filters a step to boot litter problem.

 

Robertson, R, W Thomas, J Suthar and D Brown. 2012.  Accelerated degradation of cellulose acetate cigarette filters using controlled-release acid catalysis. Green Chemistry http://ds.doil.org/10.1039/C2GC16635F.

 


Synopsis by Marty Mulvihill and Wendy Hessler, Aug 14, 2012

Context

Every year over 6 trillion cigarettes are manufactured globally. Approximately 99 percent have a filter tip. After the cigarette is smoked, the used filter is called a butt and is thrown out. When littered, cigarette butts often take years to break down.

Most filters are made using cellulose acetate fibers. More than 2 billion pounds of cellulose acetate is produced every year to meet the world demand for filters. To make it, acetic anhydride is added to cellulose fibers made from wood or cotton. The reaction creates a type of plastic that provides a stronger, more rigid filter.

By itself, cellulose fibers degrade naturally in the environment. Cellulose acetate plastic degrades very slowly.

The slow degradation, along with indoor smoking bans, mean increasingly large numbers of cigarette butts are found in public places, including parking lots, parks and beaches every year. Cigarette waste is the number one reported item collected during beach clean-ups, according to the Ocean Conservancy. In some coastal towns as many as 1 in 10 cigarette butts end up polluting the waterways.

The discarded butts are more than just an eyesore. The filters contain chemical residue from the tobacco. The residue can be toxic to marine animals. Cigarette butts are commonly found in the stomachs of dead shore birds.

One way to decrease the litter would be to create cigarette filters that degrade quickly. Previous attempts used plant-based products like cornstarch, hemp, flax or cotton. One brand of biodegradable filter, Greenbutts, incorporates plant seeds that would germinate after disposal. To date, cigarette manufacturers have not widely adopted alternative filters.

The demand for degradable filters may increase as states – including New York – consider levying taxes on non-biodegradable cigarette filters. In response, there is renewed interest to make cigarette filters degrade faster.

What did they do?

A group of chemists wondered if a cellulose acetate plastic filter could be converted back into natural, degradable cellulose after it was used. If so, the cigarette butts should degrade much more quickly.

They guessed that small amounts of acid added to the filter should speed the degradation process.

First, they measured the degradation rate of cellulose acetate using a wide range of acids with different strengths. Combinations of acids were also tested to find which worked best to make cigarette filters that retained their structure and function while degrading faster.

Next, they created an effective additive based on which acids worked best. The additive needed to be acidic, non-toxic and allow the cigarette to burn normally. To find one, they looked to acids common in food, including citric acid, phytic acid and vitamin C (ascorbic acid), as well as stronger mineral acids not commonly considered safe food additives.

The new filter design was tested. A smoking machine “smoked” the cigarettes, and the butts were left outside and monitored.

What did they find?

In the first tests, the butts exposed to water and a small amount of acid broke down faster than those not exposed to acid. Strong acids worked best to efficiently speed the degradation of the cellulose acetate fibers. In particular they found that sulfuric acid was the most effective catalyst.

Sulfuric acid, however, is not safe to put into cigarette filters. The researchers devised a way to generate the stronger acid only after the cigarette was smoked. The smoker would not be exposed to any additional harmful compounds, and the filter would degrade more quickly.

To make the acid additive, the researchers combined safer chemicals – cellulose sulfate, citric acid and phytic acid – into a tablet. When the tablet got wet, these ingredients mixed and released small amounts of sulfuric acid that degraded the filter material. The tablets were coated with ethyl cellulose and cellulose acetate to shield the acid precursors from premature exposure to water.

After 14 days outside, the butts containing the acid tablet were more acidic and tested positive for the presence of sulfuric acid, while the control butts remained unchanged. At the end of the 90-day trial, the new filters were considerably more degraded than the controls. Unfortunately they had not degraded as much as expected based on the laboratory experiments.

What does it mean?

Small amounts of strong acid increase the degradation rate of the cellulose acetate fibers found in cigarette butts. Although the idea worked in principle, the outside trials did not live up to the promise of the laboratory results.

The research is important because it is a step towards making a truly degradable and functional cigarette filter. This research shows how green chemistry can improve existing technology. The researchers designed the new filters for degradation while making safer chemical choices. This approach will ultimately minimize waste and hopefully prevent some of the toxic exposures to birds and other wildlife.

Under laboratory conditions, the acid converted the filter plastic into a biodegradable material within 30 to 60 days, depending on temperature. The food grade acids and materials generated the strong acid only after the cigarette had been smoked. These preliminary results indicate that acidic additive in the filter could reduce the time it takes for cigarette butts to degrade in the environment.

Several problems will need to be resolved before large manufacturers could adopt the use of acid tablets in cigarette filters. The filter’s effectiveness – improved degradation and materials safety of materials – will need to be quantified in clinical and environmental trials. This will take more research to design and incorporate the acid precursors into the filter body.

Cost and performance are also issues. The acid materials must be incorporated into cigarettes at a low cost without harming the performance of the product.

Researchers will llkely pursue this technology as well as other approaches to a biodegradable cigarette filter in an effort to reduce cigarette butt litter.

Resources

Clean Virginia Waterways and Longwood University. 2012. Cigarette butt litter. http://www.longwood.edu/cleanva/cigarettelitterhome.html.

Novotny, T, K Lum, E Smith, V Wang, and R Barnes. 2009. Cigarettes butts and the case for an environmental policy on hazardous cigarette waste. International Journal of Environmental Research and Public Health http://dx.doi.org/10.3390/ijerph6051691.

Ocean Conservancy. A rising tide of ocean debris, International Coastal Clean-up 2009 Report. http://www.oceanconservancy.org/pdf/A_Rising_Tide_full_lowres.pdf.

Register, K. 2000. Cigarette butts as litter: Toxic as well as ugly. Underwater Naturalist: Bulletin of the American Littoral Society http://www.longwood.edu/CLEANVA/ciglitterarticle.htm.

Leather trash turns to medical treasure.

Synopsis by Wim Thielemans and Audrey Moores, Apr 20, 2012

Catalina, M, J Cot, AM Balu, JC Serrano-Ruiz and R Luque. 2011. Tailor-made biopolymers from leather waste valorisation. Green chemistry http://dx.doi.org/10.1039/c2gc16330f.

A versatile and potentially valuable natural material could be easily collected from the abundant waste produced when leather is made from animal hides, according to researchers from Spain who explain their novel process in the journal Green Chemistry.

Leather processing generates large amounts of remnant hides that are generally thrown away. But this solid waste is rich in a valuable and medically useful protein called collagen. This new method to recycle or reuse the waste alleviates the dumping, produces a necessary product and increases sustainable manufacturing.

Collagen is abundant in mammals and is an important part of muscle, tendons, ligaments, skin, guts, vessels and bone. The resilient, soft and flexible material does not trigger immune reactions, making it a rich resource for medical, cosmetics and veterinary applications. Collagen is used for implants, as sutures and in regenerative medicine – a field of medicine that grows new human cells, tissues or organs for transplant.

The researchers tested different extraction scenarios for their effect on the amount and quality of the collagen. They extracted the protein from two different types of processed cowhides to demonstrate the versatility of the technique.

The hides were cut, treated with acid and ground into a water solution. This process allowed the collagen molecules to dissolve in water. The collagen particles ranged in size from a few nanometers to a few dozen nanometers. Because size matters for collagen applications, the particles were filtered and separated according to their size.

To find the best method, they varied a number of factors, such as temperature, leather pieces, size after grinding, the nature of the acid, stir speed and type of water solution. The optimal results for yield came from an extraction using acetic acid – basically vinegar – for 24 hours at 25oC and a smaller particle size after grinding.

Next, they manipulated the extracted collagen molecules to determine their stability and mechanical properties. In fact, the use of collagen from leather is often limited because of the poor mechanical properties of the recovered collagen. Specifically, collagen must be rigid enough while not swelling too much when exposed to water. Here the researchers found a simple chemical treatment to render the collagen firm and stable.

From this method, they made several different kinds of materials – fibers, sponges, films, threads and gels – with rigidity and swelling in water properties necessary for biomedical applications.

The research is a good example of finding new ways to use a waste material for high value applications. More work will need to be done to compare the properties of these materials with commercial collagens. The next step will be to show the collagen source is reliable and free of contamination.

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Based on a work at www.environmentalhealthnews.org.

U.S. EPA to fund “Centers for Molecular Design”.

Funding Opportunities

U.S. Environmental Protection Agency
Office of Research and Development
National Center for Environmental Research
Science to Achieve Results (STAR) Program

Centers for Sustainable Molecular Design

This is the initial announcement of this funding opportunity.

Funding Opportunity Number: EPA-G2012-STAR-C1

Catalog of Federal Domestic Assistance (CFDA) Number: 66.509

Solicitation Opening Date: December 27, 2011
Solicitation Closing Date: April 25, 2012, 11:59:59 pm Eastern Time

Eligibility Contact: James Gentry (gentry.james@epa.gov); phone: 703-347-8093
Electronic Submissions: Todd Peterson (peterson.todd@epa.gov); phone: 703-308-7224
Technical Contacts: Nora Savage (savage.nora@epa.gov); phone: 703-347-8104
José Zambrana (zambrana.jose@epa.gov); phone: 703-347-8057

Table of Contents:
SUMMARY OF PROGRAM REQUIREMENTS
Synopsis of Program
Award Information
Eligibility Information
Application Materials
Agency Contacts
I. FUNDING OPPORTUNITY DESCRIPTION
A. Introduction
B. Background
C. Authority and Regulations
D. Specific Areas of Interest/Expected Outputs and Outcomes
E. References
F. Special Requirements
II. AWARD INFORMATION
III. ELIGIBILITY INFORMATION
A. Eligible Applicants
B. Cost Sharing
C. Other
IV. APPLICATION AND SUBMISSION INFORMATION
A. Internet Address to Request Application Package
B. Content and Form of Application Submission
C. Submission Dates and Times
D. Funding Restrictions
E. Submission Instructions and Other Submission Requirements
V. APPLICATION REVIEW INFORMATION
A. Peer Review
B. Programmatic Review
C. Funding Decisions
VI. AWARD ADMINISTRATION INFORMATION
A. Award Notices
B. Disputes
C. Administrative and National Policy Requirements
VII. AGENCY CONTACTS

Access Standard STAR Forms (Forms and Standard Instructions Download Page)
View research awarded under previous solicitations (Funding Opportunities: Archive Page)

SUMMARY OF PROGRAM REQUIREMENTS

Synopsis of Program:
The U.S. Environmental Protection Agency (EPA), as part of its Science to Achieve Results (STAR) program, is seeking applications for an interdisciplinary center focusing on the sustainable molecular design of chemicals.  The aim of the center will be to develop a set of parameters and strategies that will establish design criteria regarding the properties of chemicals that will lead to the development of intrinsically less hazardous substances when compared to those currently used in society.  These newly acquired criteria and design principles will direct researchers towards the generation of novel chemicals that will minimize, and preferably eliminate, associated potential environmental and human health impacts that may occur during the life cycle of that chemical. The advent of these novel chemicals and their respective discovery of correlations between a chemical’s inherent properties and their adverse impacts require the development of improved methods for the design of next generation chemicals.

The Center will explore methods, establish knowledge bases, and develop guidance for eliminating and avoiding those attributes or properties of a chemical that most significantly influence their potential impacts. It is also anticipated the guidance for improved design and understanding of inherent chemical properties resulting from research supported under this Request for Applications (RFA) will enable continual improvements in the quality of life without detrimental impairment of public health or the ecosystem. Furthermore, the developed guidance and capability to reduce a substance’s ability to manifest hazard will result in substances which are in direct accordance with the principles of sustainability.

Note:  The term “chemicals” broadly refers to any and all types of materials, including individual chemicals, compounds or mixtures of compounds, endocrine disrupting chemicals (EDCs), and nanomaterials.

Award Information:
Anticipated Type of Award: Grant
Estimated Number of Awards: Up to approximately two (2) awards
Anticipated Funding Amount: Approximately $10 million total for all awards
Potential Funding per Award: Up to a total of $5 million, including direct and indirect costs, with a maximum duration of 4 years.  Cost-sharing is not required.  Proposals with budgets exceeding the total award limits will not be considered.

Eligibility Information:
Public nonprofit institutions/organizations (includes public institutions of higher education and hospitals) and private nonprofit institutions/organizations (includes private institutions of higher education and hospitals) located in the U.S., state and local governments, Federally Recognized Indian Tribal Governments, and U.S. territories or possessions are eligible to apply.  See full announcement for more details.

Application Materials:
To apply under this solicitation, use the application package available at Grants.gov (for further submission information see Section IV.E. “Submission Instructions and other Submission Requirements”).  The necessary forms for submitting a STAR application will be found on the National Center for Environmental Research (NCER) web site, the Forms and Standard Instructions Download Page. If your organization is not currently registered with Grants.gov, you need to allow approximately one week to complete the registration process.  This registration, and electronic submission of your application, must be performed by an authorized representative of your organization.

If you do not have the technical capability to utilize the Grants.gov application submission process for this solicitation, call 1-800-490-9194 or send a webmail message to the NCER Contact Us page at least 15 calendar days before the submission deadline to assure timely receipt of alternate submission instructions.  In your message  provide the funding opportunity number and title of the program, specify that you are requesting alternate submission instructions, and provide a telephone number, fax number, and an email address, if available.  Alternate instructions will be emailed whenever possible.  Any applications submitted through alternate submission methods must comply with all the provisions of this Request for Applications (RFA), including Section IV, and be received by the solicitation closing date identified above.

Agency Contacts:
Eligibility Contact: James Gentry (gentry.james@epa.gov); phone: 703-347-8093
Electronic Submissions: Todd Peterson (peterson.todd@epa.gov); phone: 703-308-7224
Technical Contacts: Nora Savage (savage.nora@epa.gov); phone: 703-347-8104
José Zambrana (zambrana.jose@epa.gov); phone: 703-347-8057

Full Announcement HERE.

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.

 

Shake it up: A greener method for upset tummy medicine.

André, V, A Hardeman, I Halasz, RS Stein, GJ Jackson, DG Reid, MJ Duer, C Curfs, MT Duarte and T Friščić. 2011. Mechanosynthesis of the metallodrug bismuth subsalicylate from Bi2O3 and structure of bismuth salicylate without auxiliary organic ligands. Angewandte Chemie International Edition http://dx.doi.org/10.1002/anie.201103171.

Synopsis by: Audrey Moores and Wendy Hessler, Dec 15, 2011

This sounds like a kitchen recipe: mix A with B, add a few drops of water, a pinch of salt and then shake. Except, researchers followed these simple directions in a laboratory to make the main ingredient in the popular stomach and intestinal remedy sold under the brand name Pepto-Bismol.

To make the drug this new way, they mixed the two main dry ingredients then added the rest and vigorously shook the paste in a special shaker. The breakthrough – an important step forward in the emerging field of mechanochemistry – uses less energy and solvent than the current way the drug is produced. And it creates no harmful by-products.

This discovery is showing that using simpler chemistry methods can improve processes as complex as drug synthesis and also aids understanding of how drugs work.

 

Context

The image of chemistry is intimately linked with the idea of mixing together liquids. But a new field of chemistry – namely mechanochemistry – proposes to make molecules by mixing solids without adding copious amounts of liquid solvents.

In mechanochemistry, the reagents are loaded into a small cylinder with two metal or ceramic balls. This cylinder is shaken very fast to allow proper mixing. The advantages of this technique are multiple. The products are collected pure, the reactions proceed faster than in solution, and less energy is required to perform the mixing compared to what is needed to heat large amount of solvents.

Variations of this method include addition of a few drops of solvent or a very small amount of salts. This permits the use of slower shaking, thus reducing energy use even more.

Pepto-Bismol is a popular stomach and intestinal relief medication. It is composed of a metal called bismuth and aspirine. To be active, bismuth and aspirine have to form chemical bonds together.

Currently, the drug is made by mixing water solutions of these two ingredients. After reacting, the excess water is removed, which costs energy, time and money. Previous efforts to find simpler, less wasteful, mechanical ways to manufacture the compounds have failed.

This bismuth-aspirin drug has been used for more than a century, yet chemists do not know exactly what its chemical structure looks like when the active ingredients combine. This has limited understanding of how the drug functions in the stomach.

 

What did they do?

A group of researchers from Cambridge, United Kingdom, wanted to improve the existing synthesis of a pharmaceutical group of compounds called bismuth salicylates. The most well-known variety is bismuth subsalicylate, the active ingredient in Pepto-Bismol, an over-the-counter medicine used to treat nausea, heartburn, diarrhea and other stomach and intestinal symptoms.

They were looking for a way to make the desired bismuth subsalicylate using a method that was more energy efficient, faster, yielded fewer harmful byproducts and used less solvent than the current way to make the drug.

Instead of first dissolving the two key ingredients – bismuth oxide and aspirine – in liquid solvents and then mixing the two fluids together, the researchers chose a simpler method. They mixed the dry powders in a mechanochemical mill.

It was not the first attempt to produce this drug in such a simple fashion, but past trials were met with little success. This time, the research group added a few drops of water and a pinch of salt. During ingredient shaking, the presence of the water and the salt enabled the formation of the drug in very high yields.

They tested different ratios of bismuth oxide and aspirine, different volumes of water and a variety of salts. After each attempt, they identified the products produced during the reaction.

 

What did they find?

The researchers first added a few drops of water to the bismuth oxide and aspirine powders. This helped the reaction and products did form, but none were the active ingredient bismuth subsalicylate they were looking for.

They redid the experiment adding a little bit of salt with the water to the powders. A series of different salts were tested. They discovered that potassium nitrate and ammonium nitrate were very efficient in promoting the reaction and afforded the desired drug in high yields.

The reason why the addition of water and salt is required is not completely understood, but the researchers believe that it helps the molecules organize and “find their place” in the final molecular architecture.

 

What does it mean?

By testing a new method of mixing ingredients, this group of chemists was able to produce a commercially important drug using less energy and solvent. They also are the first to identify the chemical structure of a compound similar to bismuth subsalicylate.

The discovery of this new synthetic method is important because it opens the way toward more energy efficient and less polluting drug fabrication. The chemists only had to mix two essential ingredients with tiny amounts of water and nitrate salts – less than 5 percent. Interestingly, these salts do not seem to mix with the final product, which allows for easy separation in the end. Also, this new process generates only water as a by-product. It is thus compatible with drug synthesis.

The secondary discovery of the compound’s chemical structure may seem surprising. Although it has been known for more than a century that the ingredient in Pepto-Bismol is active, the actual way it works is still unclear. In fact, no chemist had isolated and identified the three-dimension chemical structure of any bismuth salicylates. It is a little bit as if engineers were trying to understand the way an engine works without having the knowledge of the shape of its mechanical pieces.

In this study, the researchers were able to decipher the structure of a compound very close to the ingredient bismuth subsalicylate found in over-the-counter medicine. This is a vital step towards understanding the biological activity of this much-used drug. This discovery was possible because the method afforded an unusually pure product, another common advantage of mechanochemistry.

The use of mechanochemistry at a production scale has been demonstrated, for example, on the synthesis of an anti-inflammatory drug/carrier composite. This new discovery may thus lead to a more optimal production of Pepto-Bismol and other medicines. Read more science at Environmental Health News.

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.

 

Nano research leads to a greener lubricating oil.

Synopsis by Wim Thielemans, Sep 15, 2011

Majano, G, E-P Ng, L Lakiss and S Mintova, 2011. Nanosized molecular sieves utilized as an environmentally friendly alternative to antioxidants for lubricant oilsGreen Chemistry http://dx.doi.org/10.1039/c1gc15367f.

An environmentally-friendly, sieve-like nanomaterial can reduce the chemical fallout from the breakdown of lubricants better than the chemical additives now used.

Looking to solve an old problem in a new way, green chemists find that a special porous material can better reduce levels of dangerous breakdown byproducts in oil lubricants than the long-used but harmful chemicals now added. The team of researchers report their findings about the material – called zeolites – in a recent issue of Green Chemistry.

Lubricant oils reduce friction between moving parts in machines and motors in every part of society, including factory conveyor belts, cars and sewing machines. Synthetic mineral oils are used most often because they are more stable than other types. About 32 million tons of the lubricant oils leak and enter the environment every year.

To reduce human health impacts and meet new European regulatory standards, chemists are trying to find ways to make the oils both functional and environmentally benign.

One big problem with lubricants is they break down and form byproducts when exposed to oxygen – a process known as oxidation. Oxidation generates water, reactive alcohols and acids that increase corrosion and rust, thicken the lubricant, form sludge and sediment, break down the oil and create foam.

Chemical additives prevent or reduce the oxidative reactions. Unfortunately, most additives are dangerous and can impact human health and the environment. Some also affect the machine’s function, such as deactivating the catalyst converters in cars.

In this work, researchers from France, Belgium and Malaysia tested how a highly porous inorganic nanomaterial called zeolites absorb the initial oxidation products in an effort to reduce the harmful chemical byproducts that form. They did not try to stop oxidation like the current crop of chemical additives do. In theory, since oxidative reactions naturally speed up over time, removing the reaction products would reduce further oxidation, slow the process and create less harmful byproduct.

One of the three zeolites compared in the study worked surprisingly well. The researchers found the zeolite cleans up the process in two ways. First, it slowed the inherent oxidation reactions and reduced the amount of chemical byproduct produced. Second, it also absorbed the byproducts that formed. In the end, very little sludge was produced.

The zeolites used have no known adverse environmental effects and can even work together with existing oxidation-preventing chemical additives. The zeolites – when combined with perhaps a next generation of more benign additives – would then give added protection.

Future laboratory studies will need to test the performance of the numerous other zeolites available. From there, they must be tested and assessed in a real working environment. Even though this is not the final word on the technology, it looks to be very promising.

Read more science at Environmental Health News.

NIEHS scientists join forces with green chemists.

By Thaddeus Schug
April 2011

A representative diagram of the draft screening protocol  unveiled at the meeting
A representative diagram of the draft screening protocol unveiled at the meeting. The protocol is designed in a tiered approach, with rapid and cost effective screens conducted in the early phases and more extensive testing toward the end. (Slide courtesy of Pete Myers)

NIEHS/NTP scientists joined forces with leaders in the field of green chemistry in what may turn out to be a groundbreaking meeting, “Green Chemistry and Environmental Health Sciences — Designing Endocrine Disruption Out of the Next Generation of Materials,” held March 21-23 in Sausalito, Calif.

The challenges facing scientists trying to design such new materials are daunting. Say a chemist has developed a compound that he or she believes could be a replacement for bisphenol A (BPA). How will the scientist determine if the molecule is safer to human health and the environment? What testing will need to be done and what will guide scientists through this process?

The goals of the meeting in Sausalito were ambitious — to develop a consensus statement on the principles that guide the science needed to assess risks of potential endocrine disruptors, and to develop a reliable and rational testing protocol to aid chemists as they develop and bring the next generation of chemicals into the marketplace.

The intersection of green chemistry and environmental health science

Karen O’Brien, Ph.D., from Advancing Green Chemistry (AGC) and Pete Myers, Ph.D., of Environmental Health Sciences (EHS), welcomed participants to the event, which brought together an equal mix of biologists and chemists. Representatives from NIEHS and NTP included Division of Extramural Research and Training (DERT) program administrator Jerry Heindel, Ph.D., and Kristina Thayer, Ph.D., director of the NTP Center for the Evaluation of Risks to Human Reproduction (CERHR).

Following a social ice-breaking exercise on the evening of March 21, the first full day of the meeting opened with presentations from Terry Collins, Ph.D., the Teresa Heinz Professor of Green Chemistry at Carnegie Mellon University, and John Warner, Ph.D., president and founder of the Warner Babcock Institute for Green Chemistry.

Both Collins and Warner stressed the need for fundamental changes in the way that scientists design new chemicals and the process of bringing them into the marketplace. “We must also pay close attention to the environmental impact and the effects on human health posed by these chemicals, and for those reasons chemists need to work hand-in-hand with biologists,” said Warner. He also stressed that chemists generally have no background in toxicology, but that they need to be able to test the chemicals being developed for endocrine activity and to do it early on in the product development process.

Designing a chemical screening protocol

The remainder of the day was divided into discussion sessions covering each phase of a newly developed screening model, designed by a science advisory board formed by meeting organizers that met monthly, via teleconference, for six months prior to the workshop. The protocol is geared towards identifying a wide-range of endocrine-active chemicals, such as atrazine, BPA, brominated flame retardants, organotins, perchlorates, and phthalates. The Board conducted  interviews with scientists with expertise in specific areas of toxicology, endocrine disruption, and assay development.

The testing paradigm proposed involves a five-tiered approach, starting with the fastest and cheapest assays and working through more specialized tests to determine whether a new chemical has endocrine disrupting characteristics. The initial two phases rely on predictive computer modeling and high-throughput screening to quickly weed out problem chemicals. These tests are followed by more specific in vitro cell-based screening assays with a mind to refining, reducing, and replacing animal testing as much as possible.

The final two phases involve use of fish, amphibian, and mammalian in vivo modeling systems. Overall, the protocol is intended to help green chemists establish a high degree of confidence that the replacements they are developing are unlikely to be harmful to humans or the environment.

The next steps

The meeting wrapped up with discussion on how to proceed with development of the testing protocol as well as plans for implementation. The advisory board plans to use input from the meeting to develop and publish a white paper outlining guidelines that chemists can use to assess the quality of protocols and tests used to assess endocrine disruption.

(Thaddeus Schug, Ph.D., is a postdoctoral research fellow currently on detail as a program analyst in the NIEHS Division of Extramural Research and Training. He was part of the NIEHS/NTP delegation and a presenter at the meeting.)

 

Left to right, Collins, Heindel, and Warner mix ingredients  for a batch of salmon tartare.
Left to right, Collins, Heindel, and Warner mix ingredients for a batch of salmon tartare.  The cooking exercise was used as an ice-breaking event to demonstrate how environmental health scientists and chemists can work together to solve complex issues. (Photo courtesy of Pete Myers)

Laura Vandenberg, Ph.D., left, contributes to the discussion  on assay development, as Tom Zoeller, Ph.D., center, and Wim Thielemans, Ph.D.,  look on.
Laura Vandenberg, Ph.D., left, contributes to the discussion on assay development, as Tom Zoeller, Ph.D., center, and Wim Thielemans, Ph.D., look on. Vandenberg, a postdoctoral fellow at Tufts University, studies the developmental effects of endocrine disrupting chemicals. (Photo courtesy of Pete Myers)

Left to right, Bruce Blumberg, Ph.D., Thayer, and Andreas  Kortenkamp, Ph.D., served as panel members for a discussion on in vitro screening assays.
Left to right, Bruce Blumberg, Ph.D., Thayer, and Andreas Kortenkamp, Ph.D., served as panel members for a discussion on in vitro screening assays. (Photo courtesy of Pete Myers)

A group photo of the meeting attendees.
A group photo of the meeting attendees. The meeting was held at the Cavallo Point Lodge, which sits adjacent to the Golden Gate Bridge. (Photo courtesy of Pete Myers)

NIEHS  grantees Andrea Gore, Ph.D., left, and Frederick vom Saal, Ph.D., were among  panel members for the discussion on in  vivo assays.
NIEHS grantees Andrea Gore, Ph.D., left, and Frederick vom Saal, Ph.D., were among panel members for the discussion on in vivo assays. Both Gore and vom Saal are members of  the project’s scientific advisory board. (Photo courtesy of Pete Myers)

 

Emerging Environmental Health Science in Green Chemistry

NIEHS Senior Advisor for Public Health John Balbus, M.D., attended the inaugural symposium March 24 for the new University of California, Berkeley Center for Green Chemistry, entitled “Green Chemistry: Collaborative Approaches and New Solutions.” Balbus’ talk, “Incorporating Emerging Environmental Health Science in Green Chemistry,” outlined some of the challenges of applying 21st century science to protect public health.

  • How do we harness the potential of unlocking the genome?
  • Can we more accurately predict which chemicals are likely to cause harm?
  • How do we implement our understanding of susceptibility and non-chemical stressors to enhance human health?
  • How can we better incorporate new methods and technologies into science policy?

Balbus proposed that the newly developed Tox21 (http://ntp.niehs.nih.gov/index.cfm?objectid=06002ADB-F1F6-975E-73B25B4E3F2A41CB), an interagency high throughput screening initiative, is aiming to meet many of these challenges and could be a valuable tool for green chemists. Demonstrating its utility in screening chemicals for disruptions in insulin signaling, Balbus concluded, “Advancements in programs such as Tox21 will eventually allow us to accurately predict how chemicals will impact human health before they are brought into the marketplace.”