Showing posts with label chemical. Show all posts
Showing posts with label chemical. Show all posts
Friday, July 12, 2013
Wednesday, April 10, 2013
2013 economic outlook for global chemical industry
The 2013 outlook for the global chemical industry—a $3 trillion enterprise that impacts virtually every other sector of the economy—is the topic of the cover story in this week's edition of Chemical & Engineering News. C&EN is the weekly newsmagazine of the American Chemical Society, the world's largest scientific society. 
Titled "World Chemical Outlook" and compiled by a team of 10 editors and correspondents, the annual feature forecasts chemical industry growth rates in various regions, including a modest 1.9 percent increase in the United States (compared to 1.5 percent growth in 2012) and a 0.5 percent increase in Europe (an improvement from the 2.0 percent contraction in 2012).
The story describes several bright spots dotting that generally overcast landscape. U.S. chemical manufacturers, for instance, can look forward to another year of low-priced natural gas to fuel their facilities and provide cheap raw materials. Producers of "fine chemicals," highly pure substances produced in relatively small amounts for medications, pesticides and other products, should do better than the industry as a whole. Likewise, makers of scientific instruments for the energy, environmental, forensics and food markets also are upbeat about 2013 sales.
More information: "World Chemical Outlook"—cen.acs.org/articles/91/i2/World-Chemical-Outlook.html
Breakthrough in chemical crystallography
A research team led by Professor Makoto Fujita of the University of Tokyo, Japan, and complemented by Academy Professor Kari Rissanen of the University of Jyväskylä, Finland, has made a fundamental breakthrough in single-crystal X-ray analysis, the most powerful method for molecular structure determination. The team's breakthrough was reported in Nature on March 28, 2013. Provided by Academy of Finland
X-ray single-crystal diffraction (SCD) analysis has the intrinsic limitation that the target molecule must be obtained as single crystals. Now, Professor Fujita's team at the University of Tokyo together with Academy Professor Rissanen at the University of Jyväskylä have established a new protocol for SCD analysis that does not require the crystallisation of the target molecule. In this method, a very small crystal of a porous complex absorbs the target molecule from the solution, enabling the crystallographic analysis of the structure of the absorbed guest along with the host framework.
As the SCD analysis is carried out with only one crystal, smaller than 0.1 x 0.1 x 0.1 mm in size, the required amount of the target molecule can be as low as 80 ng. Fujita's and Rissanen's work reports the structure determination of a scarce marine natural product from only 5 µg of it. Many natural and synthetic compounds for which chemists have almost given up the hope of analysing crystallographically can now be easily and precisely characterised by this method.
More information: Nature 495, pp. 461–466 (28 March 2013), DOI:10.1038/nature11990
Provided by Academy of Finland Catalyst in a teacup: New approach to chemical reduction
The chemical reduction can be carried out in air - even in a teacup.(Phys.org) —Taking their inspiration from Nature, scientists at the University of New South Wales have developed a new method for carrying out chemical reduction – an industrial process used to produce fuels and chemicals that are vital for modern society. Provided by University of New South Wales
Their catalyst-based approach has the big advantages that it uses cheap, replenishable reagents and it works well at room temperature and in air – so much so, it can even be carried out safely in a teacup.
The research, by a team led by Associate Professor Stephen Colbran, of the UNSW School of Chemistry, has been published as the cover of the prestigious journal, Angewandte Chemie.
The catalyst they designed mimics the activity of naturally occurring enzymes that catalyse reduction, such as alcohol dehydrogenase in yeast, that helps produce alcohol from sugar.
"Industrial chemical reduction processes underpin human existence, but are unsustainable because they irreversibly consume reagents that are made at prohibitively high energy cost," Dr Colbran says.
"We believe our new biomimetic design may have wide applications in chemical reduction."
Chemical reduction involves the addition of electrons to a substance, and is the basis of making many fuels, including the sugars that plants produce during photosynthesis.
In industry, molecular hydrogen and reactive reagents such as sodium borohydride are used as reducing agents during the production of pharmaceuticals, agrichemicals and ammonia for fertiliser.
"Manufacture of these substances is energy costly, leads to the release of carbon dioxide and they are difficult to handle and store," Dr Colbran says. "So we decided to look at nature to see how nature does it."
The team combined a transition metal complex containing rhodium with a Hantzsch dihydropyridine – an organic donor of a hydride ion similar to biological nicotinamides – to produce the new bio-inspired catalyst. They tested it on a common process – reduction of imines – and were surprised to find it worked in ambient conditions with more than 90 per cent efficiency in most cases.
Dr Colbran even tested it out in a teacup. "I thought it would be a bit of fun. And it makes a serious point – our catalyst system is very easy to use."
By coincidence, the research comes exactly a century after Alfred Werner won a Nobel Prize for Chemistry for his work on the structures of transition metal complexes. As well, his PhD supervisor, Arthur Hantzsch, discovered the way to synthesise dihydropyridines.
"It has only taken 100 years to combine the work of doctoral adviser and student into one molecule," Dr Colbran says.
A future aim is to try to convert the greenhouse gas, carbon dioxide, into the renewable fuel, methanol, much more efficiently.
Provided by University of New South Wales Propylene oxide: Light may recast copper as chemical industry 'holy grail'
Wouldn't it be convenient if you could reverse the rusting of your car by shining a bright light on it? It turns out that this concept works for undoing oxidation on copper nanoparticles, and it could lead to an environmentally friendly production process for an important industrial chemical, University of Michigan engineers have discovered. Provided by University of Michigan
"We report a new physical phenomenon that has potentially significant practical implications," said Suljo Linic, an associate professor of chemical engineering, who led the study, which is published in the March 29 issue of Science.
Copper's newfound ability to shake off oxygen attached to its surface could allow it to act as a catalyst for a long-sought reaction, causing oxygen molecules to bind with propylene molecules in the way that forms propylene oxide. Propylene oxide is a precursor for making many plastics, toiletries and other household products such as antifreeze, paints and insulating foams. To meet demand for these products, the U.S. produces more than 2.4 million metric tons of propylene oxide per year, worth about $4.9 billion.
Unfortunately, producing propylene oxide involves a complex chain of reactions that generate unwanted chemicals. The process that provides about half of the propylene oxide in the U.S. also produces about twice as many tons of salt.
A catalyst that can coax propylene and oxygen to form propylene oxide in a direct reaction, avoiding the waste, has been called a "holy grail" of catalysis. Metallic copper showed promise, but it had—until now—been written off because it tends to bind itself to oxygen, forming copper oxide, which has poor catalytic properties.
"Copper in metallic form has this unique electronic structure that activates the reaction pathway for propylene oxide more than the undesired pathways," said Marimuthu Andiappan, a graduate student in chemical engineering and first author on the paper.
Metallic copper prefers to bind oxygen with two of the propylene's carbon atoms, forming propylene oxide. Copper oxide, on the other hand, tends to break the propylene down into carbon dioxide or attach the oxygen to only one carbon atom, resulting in the herbicide acrolein.
However, Andiappan, Linic, and former chemical engineering graduate student Jianwen Zhang found that if copper is cleverly structured, light can reverse its oxidation. The team made copper nanoparticles about 40 nanometers across, or roughly one-hundredth of the thickness of a strand of spider silk. They peppered tiny particles of clear silica with the nanoparticles and then floated a gas of propylene and oxygen over the resulting dust.
In the dark, the copper oxidized, and only 20 percent of the gas converted to propylene oxide. But under white light, five times the sun's intensity, the copper stayed in the metallic state and turned 50 percent of the propylene into propylene oxide.
"To our knowledge, this is the first time anyone has shown that light can be used to switch the oxidation state from an oxide to a metallic state," Andiappan said.
The metallic copper under the oxidized surface concentrated the light, freeing electrons from copper atoms. Those electrons then broke the bonds between the copper and oxygen.
A new kind of reactor that can illuminate the catalyst will be needed to bring this potentially cheap and environmentally friendly way of making propylene oxide to industry.
"Theoretically, it is possible to use mirrors to focus sunlight and get this much intensity," Andiappan said.
"We are just scratching the surface," Linic said. "I can envision many processes that wouldn't be possible with conventional strategies, where changing the oxidation state during the reaction or driving reactions with light could affect the outcome dramatically."
More information: "Tuning Selectivity in Propylene Epoxidation by Plasmon Mediated Photo-Switching of Cu Oxidation State," by A. Marimuthu et al, Science, 2013.
Provided by University of Michigan
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