Patent Watch

July 28, 2008

Now acrolein is a “green” chemical. Biodiesel-derived glycerol continues to receive interest as a renewable feedstock for making chemicals that are normally derived from petrochemical feedstocks. For instance, the conversion of glycerol to propylene glycol is under development by Dow, UOP, Huntsman, and others. In a separate initiative, Dow and Solvay have independently developed technology for converting glycerol to epichlorohydrin. Now, Arkema is developing techniques to convert crude glycerol to acrolein. Acrolein has a small market as a commercial product; it is more important as an intermediate in acrylic acid production.

J.-L. Dubois, C. Duquenne, and W. Holderich of Arkema describe a process for manufacturing acrolein by dehydrating glycerol in the presence of oxygen. In the patent’s examples, the reaction is carried out in a tubular reactor maintained at 300 °C. The feed stream consists of glycerin, water, and oxygen in a mol ratio of 4.5:89.5:6.0; contact time over the solid catalyst bed is 2.9 s.

One of the catalysts tested was zeolite HZSM-5. Glycerin conversion ranged from 83 to 96%, and molar selectivity to acrolein ranged from 42 to 45%. Byproducts included hydroxyacetone, acetaldehyde, propionaldehyde, and acetone. Once acrolein is separated, it can be converted to acrylic acid via oxidation using conventional means (not described in the patent). (Arkema France [Colombes]. U.S. Patent 7,396,962, July 8, 2008; Jeffrey S. Plotkin)

View patent information from CAS.

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