FRANZ J. STRAUSS, PETER PÖCHLAUER, CHRISTIAN SCHUSTER, PAUL KOHLS, STEFAN STEINHOFER, CHRISTOPHER ZINGANELL, BERNHARD GUTMANN, DAVID CANTILLO^*, C. OLIVER KAPPE^*
*Corresponding authors
Center for Continuous Flow Synthesis and Processing (CCFLOW), 
Research Center Pharmaceutical Engineering (RCPE), Graz, Austria
Institute of Chemistry, University of Graz, NAWI Graz, Graz, Austria
Patheon Austria GmbH & Co KG, Linz, Austria

Abstract

Acrolein is an important building block with widespread use in a broad range of synthetic applications. However, its high toxicity, flammability and instability toward undesired polymerizations pose significant issues for its handling, transport and storage. Thus, a robust methodology for the in situ, on site and on demand production of acrolein is highly valuable. Acrolein has been largely produced from the oxidation of propene for many years. However, as glycerol has become inexpensive and widely available from the biodiesel industry, the traditional dehydration of this renewable starting material as a source of acrolein is becoming an increasingly interesting alternative. Herein we describe a continuous version of the Adkins acrolein synthesis that permits the convenient on-demand generation of this important building block from safe and easy to handle starting materials.

INTRODUCTION

Acrolein is one of a small group of highly reactive and hazardous chemicals that have been used early in the development of organic chemistry (1). Hydrogen cyanide is a similar example. Its versatility as three-carbon building block has made it an attractive substrate for condensations, cycloadditions, and syntheses of heterocycles, amino acids and, after oxidation to acrylic acid, polymers (1, 2).

Therefore very efficient and cost-effective processes to manufacture large volumes of acrolein have been developed and are in operation on large scale (3). 

Originally, acrolein was made by high-temperature dehydration of glycerol (4). This process has largely been replaced by its synthesis from propene, with commercial routes developed by the end of the 1950s (5). Propene oxidation is typically carried out in the gas-phase employing heterogeneous catalysts. These processes are operated in dedicated plants using tailor-made equipment and catalysts (2, 3).

The increased interest to replace fossil resources by renewable sources for base chemicals (6) has motivate ...