[SUNY Potsdam]

Research

Martin A. Walker

 
Green Chemistry
Exochemistry
Fluorous Solvents
Asymmetric Synthesis
Students
 
SUNY Potsdam
Potsdam, NY 13676 

One of our major interests is in green chemistry, trying to develop viable industrial processes that can provide chemicals without damaging the environment. To that end, we have been working extensively on the Friedel-Crafts acylation reaction, which is usually a very nasty process involving two steps:

Traditionally there are several highly corrosive by-products, and even the aluminium chloride "catalyst" is usually taken away as acidic waste. We have developed a process which avoids the preparation of the acid chloride altogether, and allows the reaction to be run in one step, with the only by-product of the reaction being water.

The process does require several days of heating to go to completion, but yields with even moderately activated aromatics can be good to excellent. The catalyst is a lanthanide triflate salt, which is surprisingly affordable and is easily recycled by simply adding the aqueous layer into the following batch. Our early work was described in US Patent # 6,362,375, and further described here. Our most recent work has been submitted for publication. An interesting new reaction has been developed from this Friedel-Crafts work, namely a transacylation process that allows an acetate ester to exchange with a carboxylic acid to produce a new ester. This work was presented by presidential scholar Matthew Hudson at the 2006 ACS National meeting in Atlanta.

Meanwhile we have also been studying the reaction of fluorides with perfluorocarbonyl compounds to produce perfluoroalkoxides, with a view to making environmentally benign fluorinated fluids and fluorinated phase transfer catalysts.

Another area of interest is using our knowledge of lanthanide salts to develop convenient methods for benzylic chlorination. We now have a cerium-based method that allows benzyl chlorides to be prepared from toluenes using hydrochloric acid as the sole chlorine source.

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