Chemists at Italy's Cnr look for new hydrophobic materials Photo Credit: Mike Palazzotto

University of Buffalo-New York, have developed a new class of fluorinated hybrid materials that may open the way to Zero Emission industrial oxidation processes and other relevant applications such as chemical sensing.
The fine chemicals industry uses oxidative conversions to get most valuable products such as carbonyls by alcohols oxidation but is faced with two problems: It still uses chromium and manganese oxides in stoichiometric excess; and it uses large amounts of chlorinated and aromatic solvents (in which the reactions are carried out) which, as GlaxoSmithKline Alan Curzons put it, "despite current low prices, in addition to their impact through use and final disposal, they have a considerable life cycle impact and their total costs are not cheap".
The undesired result is indeed a waste mixture of heavy metals and contaminated solvents which, upon reaction, must be properly (and costly) processed.
The new materials developed in the lab of Italy's Research Council Rosaria Ciriminna and Mario Pagliaro of the Institute of Nanostructured Materials and Padua's University chemist Sandro Campestrini will help address this problem providing industry with high-performance materials of enormous versatility which are easily penetrated by oxygen - the most useful chemical reagent. 
A paper in the next issue (March 04) of the journal Advanced Synthesis and Catalysis describes how the research team developed such "oxygen sensitive" materials by physically entrapping a ruthenium species known as TPAP in a fluorinated silica network. The resulting hybrid material is an amorphous, highly porous oxide incorporating the organic fluorinated functions in its structure: A nanocomposite in which the fluorocarbon residues impair -- like in a Teflon pan -- a high hydrophobicity and a strong affinity for both oxygen and... carbon dioxide.
The latter gas compressed and brought to its supercritical state is now successfully employed by industry as a clean and advantageous solvent in which a host of catalytic processes are efficiently carried out over different solid catalysts. An efficient, selective oxidation aerobic process in compressed CO2 would eliminate both heavy metals and the volatile organic solvents yielding a valuable stream of pure oxygenated organics such as carbonyls in high yields. And this is precisely what the team has developed.

"Oxygen is also an ubiquitous reactant of crucial importance -- says Bright, distinguished professor at the Department of Chemistry and a member of the Center for Unified Biometrics and Sensors at the University at Buffalo University -- and it must be often quantified. We turned our attention to this analyte because of its importance and because it is moderately easy to detect. The fluorinated ORMOSILS have yielded outstanding results; the most sensitive to date."
"The fluorocarbon function, its nature and amount, and the material textural properties are the main factors dictating the desired material's reactivity properties -- says Rosaria Ciriminna, first author on the ASC paper --. Understand this relationship will be crucial in developing the devices needed in different applications.
"Whether catalysis or chemical sensing -- adds Pagliaro -- the technological impact of this discovery is relevant for applications which can be expected in sectors as different as the energy and chemical industries, medicine, environment and biochemistry".
"The concepts are general -- confirms Campestrini, a chemistry professor in Padua -- and the materials have the profound versatility typical of sol-gels. And since there are a lot of oxidative conversions which might be transferred to carbon dioxide and mediated by similar materials, a family of new materials will grow from ours."

The work was dedicated to Dr. David Applebaum, the eminent physician passed away with his daughter Nava in Jerusalem last September at the age of only 50.
 

CONTACT INFO

Mario Pagliaro
Institute of Nanostructured Materials, Cnr
Palermo (Italy)
phone: +39 091 680-9370
email: pagliaro@pa.ismn.cnr.it

Frank V. Bright
Department of Chemistry
University at Buffalo
The State University of New York
phone: (716) 645-6800 ext. 2162
email: chefvb@buffalo.edu

Sandro Campestrini
Department of Organic Chemistry
University of Padova
phone: +39 049 827-5289
email: sandro.campestrini@unipd.it