Novel Selective Heterogeneous Amination Processes for the Synthesis of Bio-based Monomers – SHAPes

WP1: Preparation of a library of catalysts
WP1 intends the preparation of a library of heterogeneous catalysts for developing the borrowing hydrogen mechanism for direct alcohol amination. The catalysts, once prepared and characterized using standard techniques, will be subjected to a catalytic quality test (e.g., liquid-phase catalytic amination of benzyl alcohol with aniline) to assess for their potentials in the further synthesis of primary amines. The most promising formulations will be subjected to deeper characterization studies (e.g., EXAFS, LEIS).
WP2 and WP3: Gas- and liquid phase alcohol amination studies
WP2 and WP3 will focus on gas- and liquid-phase amination studies with ammonia first on model monoalcohols, and later on the target diols (e.g., isosorbide, 1,3-propanediol) using the most promising catalytic formulations supplied by WP1. High throughput techniques for gas-phase amination will be implemented (RealCat platform) to accelerate catalyst discovery. Some pilot tests under water extraction are also proposed at the end of WP3.
WP4: Advanced characterization and mechanistic studies
WP4 is divided into two tasks: (1) study or the reaction kinetics using labeled molecules (SSITKA tests) and operando IR amination tests under gas phase, and (2) simulation studies for understanding the nature of active sites on model metal-supported catalysts.
WP5: Kinetic studies
WP5 will focus on the kinetic modeling of the experimental results obtained in gas- and liquid-phase amination studies (WP2+WP3) for the most efficient catalysts. As an output from the modeling, detailed information on activation energies and adsorption properties will be obtained, which will be further contrasted to the information gathered from simulations in WP4.
WP6: Applicability, scale-up, industrial valorisation, LCA
Using the body of data collected in WP1-WP3, upscaling and eco-efficiency studies will be carried out to orientate the generated knowledge to well-defined applications.

During the period T0-T12, UCCS Lille has prepared 34 metal-supported catalysts using the Chemspeed robot available at the REALCAT platform. Overall, six different metals (Pd, Pt, Ni, Co, Cu) have been impregnated over five different supports (?-Al2O3, SiO2, HS-CeO2, TiO2, Fe2O3). In addition, 2 Co/Al2O3 and 2 Co/CeO2 catalysts have been prepared by wet impregnation, one of each type in the presence of ?-cyclodextrin. In parallel, UCCS Valbio has built a new fixed bed setup for performing gas-phase amination reactions under ammonia. A high throughput test of the different catalysts has been implemented in the REALCAT platform to screen their catalytic activity in a model amination reaction.
E2P2L has prepared a series of Pd-supported catalysts. The results show an unexpected correlation between the reversible H2 storage capacity and the yield towards the secondary amine for the model amination reaction of benzyl alcohol with aniline or ammonia. In both cases, the catalytic activity appears to be governed by the dehydrogenation of benzyl alcohol. In parallel, E2P2L has carried out some liquid-phase amination tests of ethyleneglycol with ammonia using a collection of metal-supported catalysts. The results show high alcohol conversion, but only moderate selectivity to mono- and diamines.
ENSL has carried out some preliminary DFT simulations to study the alcohol dehydrogenation and imine hydrogenation steps in the H2 borrowing mechanism over model Ni(111) and Pd(111) slabs on the model amination reaction of methanol with ammonia. The first results point out a slightly lower energy span for Ni(111) and methanol dehydrogenation as the limiting step of the H2 borrowing mechanism.
UCCS-EM has carried out DFT simulations to study the reactivity of supports in amination reactions. A complete study has been performed over ZrO2 for the model amination reaction of ethanol with ammonia.
As scheduled in the proposal, LCS has not started yet the activities.

The perspectives for the period T12-T24 are the following:

UCCS Valbio / Casu / E2P2L: Complete the library of metal-supported catalysts prepared either manually or at the RealCat platform and screen their behavior in the model amination reaction of benzyl alcohol with aniline. Survey the effect of metal dopants and mixed oxides on the catalytic activity and selectivity for the best catalytic systems. Perform a complete characterization study before and after reaction (e.g., metal dispersion, reducibility, particle size) for the best catalytic formulations.
E2P2L: For the best formulations, perform systematic studies to assess the effect of the different variables on the catalytic activity and yield to the primary amine for the gas- and liquid phase model amination reaction between 1-octanol and ammonia (e.g., ammonia/alcohol ratio, ammonia/hydrogen ratio temperature). In addition, preparation of a systematic series of catalysts by finely tuning the calcination temperature, metal loading / speciation and reduction temperature. These latter series are intended to support the simulation studies carried out at ENSL and UCCS EM.
In parallel, survey the catalytic performance of the best formulations in the amination of target diols (with preference isosorbide and 1,3-propanediol).
ENSL: Complete the calculations surveying the effect of NH3 and H2O for methanol dehydrogenation and methylimine hydrogenation on different metal slabs and comparison to experimental data.
UCCS EM: Complete the calculations on ZrO2 and ?-Al2O3 and comparison to experimental data.
LCS: Measure the IR signature of methanol and NH3 on different supports and metal-supported systems and start operando IR amination studies.

M. Pera-Titus, F. Shi, Catalytic Amination of Biomass-Based Alcohols (Highlight), ChemSuSChem. 7 (2014) 1-4.

A. Dumon, C. Michel, P. Sautet, F. De Campo, M. Pera-Titus, Amination Séléctive des Alcools, 14ème Rencontre des Chimistes Théoriciens Francophones (RCTF2014), Paris, Juillet 2014.

SHAPes proposal aims at the development of eco-efficient processes for the synthesis of highly valuable diamine monomers (either new or already existing) using platform molecules obtained from biomass upgrading (especially diols such as hydroxylmethyl furfuryl alcohol or HMFA and isosorbide).
Overall, the manufacturing technologies for fatty and specialty amine production are mature, so dramatic innovations in the industry have not occurred in recent years. In particular, the synthesis of primary amines still presents some unsolved challenges, especially when it comes to the preparation of polyamines. Developing more selective and ideally continuous processes to produce large-volume primary amines such as hexamethylenediamine (HMD) or dimethylamine (DEA) could represent an economical step change for such products. At the same time, the exploitation of biomass to produce fuels and valuable chemicals may provide in a near future a range of diols that could present market opportunities to develop new monomers with unique properties. Thus, the valorisation of such diols could contribute significantly to the economical viability of the use of biomass for chemical production.
Among the various processes to prepare amines, the reaction of ammonia with alcohols is particularly attractive because of the availability of various types of alcohols and the fact that water is the main by-product. However, to our knowledge, no industrial process is available to date for diamine production from diols due to the lack of selectivity of the current amination catalysts (operating via nucleophilic substitution and reductive amination mechanisms). To minimize both the cost and the environmental impact of such transformation, it would be highly desirable to develop selective heterogeneous catalysts and if possible processes that could be run continuously. To this aim, we will explore the potentials of borrowing hydrogen mechanisms, offering two major benefits beyond the state-of-the-art: (1) no external hydrogen supply is required as in commercial reductive amination catalysts, and (2) it avoids the direct attack of low-nucleophilic ammonia to the alcohol.
This proposal joins the efforts of 1 industrial and 4 academic partners (i.e. Solvay-China, E2P2L, UCCS-Lille, ENS-Lyon and LCS-Caen) towards a common goal: the development of cutting-edge heterogeneous catalysts for the direct amination of bio-sourced diols to afford the preparation of primary amines with optimal yields. The project is organized in eight different tasks with balanced scientific/technical skills between the partners: (WP0) coordination; (WP1) preparation of a rich diversity of heterogeneous catalysts with tailored redox and acid-base surface properties using high throughput techniques when necessary; (WP2+WP3) gas- and liquid-phase amination reactions with ammonia; (WP4) advanced characterization and mechanistic studies to unveil the nature and dispersion of catalytic sites and the relative balance between redox and acid-base properties for “hydrogen borrowing” avoiding polymerization and cyclization side reactions; (WP5) kinetic studies including modelling; (WP6) applicability, scale-up, industrial valorisation, LCA; and (WP7) dissemination and impacts. The project is structured around three ambitious yet realistic quantitative milestones on the catalyst performance (i.e. selectivity and activity).
The final success of the project will be evaluated on the basis of the performance, stability and recyclability of the different catalytic formulations for carrying out either gas- or liquid-phase amination reactions with ammonia on the target diols. Detailed pilot tests and upscaling studies will be considered depending on the results obtained. Finally, with all the results in hand, techno-economical and LCA analyses will be performed to survey the industrialisation potentials of the different catalytic technologies developed in this project.