English  Sprachen Icon  |  Gebärdensprache  |  Leichte Sprache  |  Kontakt


Propane to acrylic acid

Frederik N. Naraschewski

Acrylic acid is used in the chemical industry as monomer for special application polymers and has a high and fast growing demand. Therefore, a direct route from propane to acrylic acid (Figure 1) is of high economic interest in order to replace the currently used two step oxidation from propene to acrylic acid.

[Bildunterschrift / Subline]: Figure 1: Direct process of propane oxidation to acrylic acid

The balance between a high activity for the activation of the C–H bond in the alkane and the stabilization of the acrylic acid, i.e. to prevent the subsequent oxidation to COx, are the major challenges in this reaction. In the conventional two step oxidation of propene to acrylic acid (Figure 2) the different reactivities are controlled by using different catalysts and temperatures for the oxidation of propene (600 K) and acroleine (520 K). For the direct one step process starting from propane a highly active catalyst for the activation of propane and a highly selective catalyst for the subsequent oxidation of the intermediates to acrylic acid is essential to carry out all reactions at the same temperature.


[Bildunterschrift / Subline]: Figure 2: Conventional two step oxidation of propene

Multi component mixed metal oxides containing MoVTeNbOx were reported to be the most promising catalysts for this reaction, showing yields up to 50% at temperatures between 620 and 720 K. Two crystalline phases of MoVTeNbOx oxides, known as M1 and M2 phases, are in the focus of the scientific discussion for the oxidation of propane to acrylic acid. The phase described as M1 consists of molybdenum-oxygen and vanadium–oxygen octahedra that form a layer structure with channels perpendicular to the ab plane (Figure 3). The M2 phase is also a layered structure formed form octahedral with molybdenum, vanadium and niobium centers. Tellurium occupies the hexagonal channels.


[Bildunterschrift / Subline]: Figure 3: Structure of MoVTeNbOX M1 and M2-phase

Project objectives are determination of synthesis and metal influence on catalytic activity and modeling of the reaction network to explain product distributions for different contact times and temperatures. A further understanding of the processes on the catalysts, the active site and the factors that limit the yield of acrylic acid should lead to the development of improved catalysts.


[Bildunterschrift / Subline]: NanoCat Student Frederik N. Naraschewski

Frederik N. Naraschewski
* 1979