From Glycerol to Acrylic acid via LACtic acid – GALAC

Due to the predictable rarefaction of petroleum, it is essential to develop new approaches for the synthesis of intermediate products such as acrylic acid. This C3 platform molecule is produced now at 4Mt/year from propene. One alternative route is the synthesis of acrylic acid in two steps from glycerol with acrolein as intermediate. But this strategy leads to expensive supercritical and acid conditions or to rapid catalyst deactivation. Hence, no industrial transfer is expected for the moment using this chemical route. In this project, we propose to prepare acrylic acid from glycerol but via lactic acid intermediate. This project is in adequation with the Axis 1 of the proposal.

To our knowledge, this parallel route has not been studied and covered two important successive steps: the first one yields to the formation of lactic acid which is also an important molecule platform (precursor of polylactic acid, pyruvic acid) and for which very few studies has been carried out. The second step, the dehydration of lactic acid to acrylic acid, is very sensitive due to the high reactivity of the product and the large problems of deactivation of the catalyst. While the dehydration reaction is well known for a large range of substrates, very few reports concern their application to lactic acid dehydration. We wish to study carefully these two steps considering the added-value of both products (lactic acid and acrylic acid). The development of heterogeneous catalysts will be studied to achieve high yields in both steps. Then the lactic acid formed in the first step wil be used in the second step without drastic purification.

We will develop the synthesis and the characterization of the catalysts for each step (supported metallic catalyst for the first step and solid acid for the second step) and we will adapt the reaction conditions to reach the highest yields. The support of theoretical teams will help in understanding the reactivity of the highly functionalized glycerol substrate and lactic acid over different model catalysts and to design the best catalytic systems. The combination of these different contributions will help to establish the viability of the system. Futhermore, a constant exchange with the industrial partner involved in this project will be a guidance for experimental conditions optimisation to transfer as quickly as possible the processes to industry.

This project gathers 5 academic research teams and an industrial partner to take benefit from all competences: theoretical studies of heterogeneous catalysis, experimental skills in developping new metallic or solid acid catalysts, industrial transfert.