NEWS OF THE WEEK I M
M I M I I I I
SUPERCRITICAL
I I I I I
M IT F
CHEMISTRY
HYDROGENATION WITHOUT GASES Hydrogen and supercritical fluids are formed in situ from liquid precursors
GASLESS PROCESS H2/C02 mixture generated in reactor 1 hydrogenates substrates such as cyclohexene or 1-octene in reactor 2.
CONFLICTS
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Y SIMULTANEOUSLY GENER-
ating both hydrogen and supercritical carbon dioxide, a new continuous hydrogenation process avoids the problems of handling gases under pressure. D e v e l o p e d by chemists at the University of Nottingham, in England, the gasless laboratory technology relies on the decomposition of liquid formic acid, H C 0 2 H , over a heated platinum or palladium catalyst at 450 °C in a miniature reactor. The resulting H 2 and supercritical C 0 2 are mixed with the material to be hydrogenated, then passed over a noblemetal catalyst in a second reactor. "The gasless equipment is simple to use and eliminates the need for high-pressure gas cylinders," says chemistry professor Martyn Poliakoff, who developed the
OF
process with postdoc Jason R. Hyde [Chem. Commun., published online May 27, http://www. rsc.org/is/journals/current/chem comm/ccadvarts.htm]. Decomposition of H C 0 2 H yields H 2 and C 0 2 in a 1:1 ratio. Feeding liquid ethyl formate, H C 0 2 C 2 H 5 , into the first reactor, where it decomposes to C 0 2 and ethane, can lower the H 2 concentration. The parallel decomposition of H C 0 2 H and H C 0 2 C 2 H 5 allows control of the H 2 concentration in the supercritical C 0 2 / C 2 H 6 mixture. Decomposition ofHC0 2 C 2 H 5 in the absence of H C 0 2 H opens up possibilities for carrying out other supercriticial fluid reactions. Hyde and Poliakoff have demonstrated, for example, that the equipment can be used for acidcatalyzed Friedel-Craft alkylations. The Nottingham team members have been collaborating with HEL, a company based in Hertfordshire, England, that produces research-scale automated equipment, to develop the technology HELwill launch a commercial version of the equipment next month.
INTEREST
FDA Examines Its Ethical Standards
A
recent FDA review to assess compliance with the agency's ethical standards shows that "the aggressive disclosure and review process designed to prevent conflicts of interest is working well/' says Acting FDA Commissioner Lester M. Crawford. Following a House Energy & Commerce subcommittee hearing in May that
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raised questions about conflict of interest at FDA, the agency undertook a review of its employees' adherence to conflict-ofinterest regulations. Crawford announced the results of that review on June 4. The conclusions are based on more than 1,800 submissions from agency employees of their outside activities. After the hearing in May, FDA began to
"Our gasless technology unit eliminates the need to store, meter, and control gases," says HEL Managing Director Jasbir Singh. "The unit contains the electronics, the pumps, the pressure and temperature controls, and even an embedded computer with preloaded software." The equipment can be used to automatically vary the process parameters for hydrogenations, polymerizations, and for other processes, he points out. David J. Cole-Hamilton, a chemistry professor at the University of St. Andrews, in Scodand, and an expert on supercritical chemistry believes the technology provides an attractive new route into supercritical reactions. 'Although industry has learned to handle pressurized gases, they represent a considerable hazard," he says. 'Any method for reducing their inventory holds significant safety advantages. The Chemical Communications paper presents an elegant method for doing this." Problems still need to be overcome, however. For example, H C 0 2 H decomposition leads to the generation of small quantities of carbon monoxide and water. If this decomposition is not controlled, "the concentration of CO in the gases generated will rise," the authors note. "Currently, we are investigating how the presence of CO in the H 2 / C 0 2 mixture can be exploited for gasless supercritical hydroformylation."—MICHAEL FREEMANTLE
tighten its conflict-of-interest regulations. It required that each agency director personally review all employee requests for outside consulting activities. Now, the agency is expanding the number of employees that must file declarations of financial holdings and conducting an annual review of outside activities. "These are good first steps, especially if the requests for outside activities will be accessible to the public," says Jeffrey Delviscio of the Center for Science in the Public Interest.—BETTE HILEMAN
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