Sunday, February 17, 2013

Useful chemicals and fuel from Carbon dioxide

Carbon dioxide is abundant, non-toxic, inexpensive, and a renewable source of carbon. This makes CO2 the most coveted compound by Green Chemistry enthusiasts. Industries are always on the lookout for ways that will enable effective use of CO2 to act as synthetic building blocks for producing fuels like Methane, Di-methyl-ether and Mthanol and fine-chemicals. Furthermore, CO2 conversion could also help reduce atmospheric CO2 levels, popularly known as “Green House Gas”, and thus, protect climate.

Nature has been highly successful in using CO2 as synthetic building blocks in photosynthesisFor decades, scientists have been trying to understand this phenomenon at a molecular level. Such studies have proved useful in developing biomimetic catalysts for CO2 conversion. Chlorophyll (Porphyrin molecules) in green plants helps convert incident sunlight and atmospheric CO2 into sugars (energy). So, this makes them promising target for testing activation catalysts for CO2 adsorption. Effective CO2 adsorption using man-made catalysts is indeed our end-goal. Lot of research is being conducted in this area to further the economic viability of the processes that utilize CO2. Several companies are pursuing the idea / concept of thermochemical and electrochemical conversion of CO2 into chemical feedstock or polymers. Research and development are currently focused on increasing the catalyst life and bringing down the temperature of conversion.

Future research must emphasize on the rational design of highly active catalyst, in order to satisfy the economic development of CO2 conversion. But, the development of such efficient catalysts requires a complete understanding of CO2 and CO2-catalyst interactions.

In order to develop such a catalyst, following points should be considered,
  1. CO2 has strong affinity towards nucleophiles and electron-donating reagents, due to the electron deficiency of its carbonyl-carbon,  If the designed catalyst has nitrogen or base-functionalty (basic), it will have an increased affinity towards CO2 (eg, Porphyrin, Grignard reagents). Such catalysts lead to the synthesis of acid-derivatives.
  2. With low-valent metals and alkene, CO2 undergoes “oxidative cycloaddition”
  3. New CO2 soluble catalysts may increase efficiency.
  4.  Homogeneous catalysis in compressed CO2, may increase selectivity.
  5. Catalyst in supercritical CO2 may also increase stability. It is essential to make use of CO2, based on the unique physical properties as that of the supercritical fluid, either as a solvent, or as an anti-solvent, or reactant, or a combination of all.
  6. Photoelectrochemistry, the study of using solar energy to split CO2, is an emerging method for clean production of chemicals. It is also important to develop catalysts (Semiconducting materials) for the electrochemical conversion of CO2.
  7.  Use of high-energy starting materials may ease the catalyst role.
  8. The catalyst will be more efficient if it has both CO2 adsorption and activation functionality. Eg, designer MOF that contains Lewis-base sitewill donate electron to CO2, in contrast to the Lewis-acids sites in traditional MOFs for adsorbing CO2.
  9.  Computational tool such as Density Function Theory (DFT) may help improve the catalytic activity, or, find a new catalyst.
  10. Chemical reactions can also benefit from using CO2 as a mild oxidant, or as a selective source of O2 atoms because dissociation of CO2 on a catalyst-surface could produce active O2 species.

 The trend towards conversion of CO2 to useful chemicals and fuels will probably intensify in the near future. This could in turn lead to effective management to tackle climate change and energy crisis.

As George Whitesides emphasizes, managing CO2 and conversion into useful chemicals and energy will be the reinvention of chemistry, and it is also chemistry/ molecular solution to the important problem facing the society.  He says

 “Some of the most interesting problems in science, and many of the most important facing society, need chemistry for their solution. Examples include: understanding life as a network of chemical reactions; interpreting the molecular basis of disease; global stewardship; the production, storage, and conservation of energy and water; and the management of carbon dioxide."

Issues pertaining to CO2 is truly global, and a major opportunity for the development of sustainable energy options and environmental preservation. So, use of CO2 for the synthesis of useful chemicals & fuels will mark a new field in chemistry. It is important to establish university-industry-collaboration to search for new-reactions & new-catalysts in this field.

To Readers: If you have experience with CO2 conversion reaction or specific catalyst, please feel free to comment.

Saturday, February 2, 2013

Hope for Drug to Reduce Old-Age-Related Muscle Wasting

Guest Post – Lily Bryant

The results of a study carried out by researchers at the Center of Regenerative Medicine at Massachusetts General Hospital in Boston, USA, and the Department of Craniofacial Development and Stem Cell Biology at King’s College London, England, indicate that a cure for muscle weakening caused by old age might be on the horizon. Muscle wasting is an inevitable symptom of growing older. It can be slowed down by regularly exercising but there is no known way of reversing it at the moment. This looks set to change though, as the researchers have treated old mice with a drug that has significantly improved the ability of their aged muscle tissue to self-repair. 

Fibroblast Growth Factor 2 

Strenuous activity, such as doing press-ups or lifting weights, results in a small level of damage to the muscles. Stem cells are triggered to repair them by dividing and developing into new muscle fibres. This results in big arms and rippling torsos. However weakening of the muscles due to old age means that bulging biceps can soon become puny and weak. This occurs because as people grow older, their muscle loses its ability to regenerate. A study conducted by the University of Potsdam in Germany indicates that people lose just under a third of their muscle strength between the ages of fifty and seventy. The researchers at Massachusetts General Hospital and King’s College London deduced that this is due to the fact that the number of dormant stem cells in muscles decreases with age. They concluded that in mice, this was caused by excessively high levels of a protein that stimulates cells to divide, known as fibroblast growth factor 2 (FGF2). 

Preventing Muscle Stem Cell Decline 

In ageing muscle, fibroblast growth factor 2 was found to be continuously awakening dormant stem cells for no reason. The stem cell supply was observed to deplete over time, meaning that an insufficient number were available when they were really needed. As a result of this, muscle regeneration ability was impaired. The researchers discovered that using a drug called SU5402 that inhibits fibroblast growth factor 2 can prevent muscle stem cell decline in aging mice. Treating the elderly rodents with this drug increased their ability to repair muscle tissue. 

Reducing the Impact of Old Age 

Dr Albert Basson, who is a senior researcher at King’s College London, has stated that the findings mean that treatments that could make old muscles young again could one day be developed, thus reducing the impact of old age. He says that if such a treatment came into existence, people would be able to live more independent, mobile lives as they grew older. Senior author Dr Andrew Brack of Massachusetts General Hospital says that just as it is important for athletes to schedule recovery into the time that is taken for training, stem cells require time in which to recuperate but elderly cells recuperate less often. Scientists are yet to figure out why it is that levels of fibroblast growth factor 2 increase causing excessive stem cell activation as people get older. Research team member Kieran Jones of King’s College London says that the next step is to conduct an analysis of old muscle in humans in order to see whether or not the same mechanism is responsible for the depletion of stem cells in human muscle fibres leading to wasting and loss of mass. 

The Implications of the Research 

Once it has been confirmed that stem cells in human muscle fibres are negatively affected by fibroblast growth factor 2, work can start on introducing a drug to the market that will stop the process from taking place and consequently reduce the extent to which elderly people are immobilised and prevented from doing what they want to do by the effects of age-related muscle weakening. The average life expectancy in India has increased by over four and a half years since 1998. Now that people are living longer than they used to live for, a drug that reduces the amount to which becoming elderly negatively impacts upon the quality people’s lives would be extremely beneficial. It would mean that individuals who have reached the later stages of their lives could enjoy the time that they have left without having their independence limited by their muscles becoming increasingly weak and feeble.

About Lily Bryant

Lily Bryant is a writer working with one of only two licensed online pharmacies in the US. She is strongly interested in promoting and creating content aimed at relevant readers as part of her role in ethical healthcare business. She believes that it is important that we play a strong role in leading society towards a healthier lifestyle through the promotion of exercise and healthy diet rather than an early adoption of drug treatment.

Friday, February 1, 2013

Artificial Photosynthesis using graphite Carbon Nitride

Fine chemicals and hydrogen production from water, carbon dioxide and solar energy is an ideal future chemical and energy source, independent of fossil reserves. The development of new functional molecular materials (catalyst) for the application in fine chemical and clean energy production using water and solar energy is fascinating and quite challenging, because the catalyst must be sufficiently efficient, stable, inexpensive and capable of harvesting light. 

Polymeric graphite carbon nitride (C3N4) materials are commonly available simple semiconductor photo catalyst. Being non-volatile up to 6000C even in the air with no detectable solubility or reactivity in conventional solvents, including water, alcohols, DMF, THF, diethyl ether, and toluene. Carbon nitride is considered to be extremely stable and basic in nature. It can be used as the multifunctional heterogeneous catalyst for fine chemical and pharmaceutical synthesis as well as a good organic semiconductor due to its right band gap (2.7 eV corresponding to an optical wavelength of 460 nm). 

Prof. Markus Antonietti and his team at Max Planck Institute of Colloids and Interfaces in Germany, have successfully split CO2 or photochemically turn water into hydrogen and oxygen using graphite carbon nitride. However, only four micromoles of hydrogen per hour produced out of the re-searchers' reaction vessel (quantum efficiency of the Pt modified CN is approximately 0.1% with irradiation of 420-460 nm). This opens the door to artificial photosynthesis and produce chemicals and energy from green house gas /solar energy. It will contribute to the prevention of global climate change.