Proposal summary: The transformation of lignocellulosic biomass into fuels or reaction synthons of interest for fine chemistry is an essential issue for reducing the environmental impact associated with the use of fossil resources. Contrary to cellulose and hemicellulose, lignin is a resource that is still not very well valorized, although it is abundantly produced by the pulp and paper industry and will be an abundant by-product of next generation cellulosic biorefineries. Different technologies exist for lignin liquefaction, but fast pyrolysis has undeniable advantages. It can convert 60-75% of lignocellulosic biomass into crude bio-oil, and it operates continuously, in an inert environment, and without solvent consumption. However, the bio-oil must be upgraded to be valorized. Containing up to 55% of phenolic compounds, it is a source of simple aromatic hydrocarbons (BTX). Catalytic hydrodeoxygenation (HDO) is the most suitable catalytic process to transform phenolic monomers into BTX. The catalyst, by selectively activating the C-O bonds, will allow the deoxygenation of phenolic compounds while avoiding their hydrogenation. These two processes are therefore essential to ensure the economic viability of biorefineries through a better valorization of the lignocellulosic fraction. The project aims developing original catalysts for the deoxygenation of lignin pyrolysis vapors, with the goal to improve the yield of aromatic hydrocarbons. In order to gather skils in materials chemistry, molecular modelling, heterogeneous catalysis and process engineering, the project team associates 5 laboratories, labelled by CNRS: UCCS (Univ. Lille), IC2MP (Univ. Poitiers), and L2CM, LPCT, and LRGP (all three from Univ. Lorraine). The skills thus gathered allow the development of a multi-scale approach, from ab initio modeling at the molecular scale of surfaces to the study of catalyst performance on lignin pyrolysis vapors from a continuous hydropyrolysis process.
The PhD project will aim at synthesizing heterogeneous catalysts based on abundant metals, whose key parameters will be optimized: (i) textural properties of the supports, and in particular the stabilization of a hierarchical porosity, (ii) oxophilicity / acidity of the surface, (iii) and fine characteristics of the metals (dispersion, localization and composition). Thus, silica supports with hierarchical porosities will be synthesized, modified by the introduction of different oxide phases (ZrOx, TiOx, AlOx, ZnO), and then the metal phases (Ni, Fe, Co and Cu) will be dispersed in a controlled manner on the surface of the pores to obtain single atome to clustered supported catalysts. These catalysts will be studied for the HDO of model oxygenated molecules (m-cresol, anisole and guaiacol) under moderate hydrogen pressures (2-4 MPa) before being tested on real lignin in a reaction micropilot (IC2MP partner). The properties of the catalysts (activity, aromatic yield, and stability) will be rationalized by DFT studies conducted on the adsorption of model oxygenated molecules, taking into account the effect of H2O, CO and CO2 inhibitors (LPCT partner). All these results will allow the description of the reaction pathway and the obtaining of key kinetic data in real conditions of reaction conducted over lignin (at LRGP partner).
Starting date: Flexible, until march 2022
Application: CV + motivation letter by email to the supervisors
Contact: Sebastien Royer, Professor Université de Lille, France (email@example.com) & Nadia Canilho, MCF Université de Lorraine, France (firstname.lastname@example.org)
Laboratory information: French partner: http://uccs.univ-lille1.fr/index.php/en/heterogeneous-catalysis/matcat
Salary: Approx. 1600 euros net/month
Background: This request is made in the context of the development of photoactive molecular systems for health, in particular for applications in phototherapy, opening the way to the treatment of many pathologies, including those of infectious and cancerous origin, using light.
Recent work carried out in the laboratory concerning the preparation of potential macro-bis-heterocyclic bis-imidazolium N-heterocyclic carbene (NHC) ligands, have shown interesting intrinsic photophysical and biological properties of these molecules, with a production of singlet oxygen (1O2), in yields of up to 84% for some of the macrocycles obtained. We wish to continue these syntheses in order to modify the structures and improve their photoactive properties with a shift towards higher wavelengths (> 800 nm) in particular for applications in phototherapy. We aim at preparing structures with a higher conjugation but also a larger size allowing a better coordination of transition metals (e.g. Zn (II), Ag (I), Au (III), Pt (II), Fe (II)).
Objectives: The Master 2 subject will concern the organic synthesis of original N-macro-bis-heterocyclic carbene ligands and the metal cation complexes of the isolated compounds (scheme above), as well as their characterization.
Methodology: The candidate will perform organic synthesis reactions and characterization of the isolated molecules by classical physicochemical methods (Infra Red (IR), Nuclear Magnetic Resonance (NMR), mass spectroscopy, microanalysis, etc.). The study of their coordination properties will then be carried out. Depending on the progress of the synthesis, the analysis of the photo-physical properties (fluorescence, 1O2, photoacoustics) and the application in biology (cytotoxicity, antimicrobial/antiviral properties, antiproliferative) will then be discussed in collaboration with Dr. Mihayl VARBANOV.
Desired profile: The candidate should have a strong knowledge in organic synthesis methodology and coordination chemistry. He/she should have the necessary knowledge of physico-chemical analysis (IR, NMR, mass spectroscopy, microanalysis). Good knowledge in biology is welcome. For international candidates, a good command of English is sufficient (a good knowledge of French would be appreciated).
Application: Applications should be sent to Florence Dumarçay (email@example.com) and must include a CV and the transcript of records of BSc and MSc levels.
Background: The development of photoactive molecular systems, with application in phototherapy, opens the way to the treatment of many pathologies, including those of infectious and cancerous origin, using light. Recent work carried out in the laboratory concerning the preparation of potential macro-bisheterocycles bis-imidazolium ligands NHC (N-heterocyclic carbene) in coordination with transition metals (e.g. Zn (II), Ag (I), Au (III), Pt (II), Fe (II)), has shown interesting intrinsic photophysical and biological properties of these molecules. These observations concern particularly the production of singlet oxygen (1O2), the yield of which can reach 84% for some of the macrocycles obtained, as well as the antibacterial activities. We wish to continue the biological characterization of these structures in order to improve their photoactive properties, in particular for applications in phototherapy (PT).
Objectives: The objective of the traineeship will concern the biological characterization of the original N-macro-bis-heterocyclic carbene ligands and the metal cation complexes of isolated compounds (illustrated above). The focus will be on evaluating the anti-infectious properties of the molecules, in presence or absence of irradiation.
Methodology: The candidate will carry out the evaluation of the antibacterial (pathogenic strains, microbiota strains) and antiviral (coronavirus, herpesvirus) properties of the compounds, as well as the evaluation of their impact on the host cells (cytotoxicity, hematotoxicity). The link with photo-physical (fluorescence, 1O2, photoacoustic), physico-chemical and structure-activity relationships will then be discussed in collaboration with Dr. Florence Dumarçay.
Profile of the candidate: The candidate should have solid knowledge in bacteriology / virology and cell culture. He must have the necessary knowledge for analyzes in cell biology (light microscopy, immunofluorescence, FACS, Western blot), molecular biology (PCR, RT-PCR) and biochemistry. Good knowledge in chemistry / physical-chemistry will be welcome. For international applicants, fluency in English is sufficient (a good foundation in French will be appreciated).
Application: Applications should be sent to Mihayl Varbanov (firstname.lastname@example.org) and must include a CV and the transcript of records of BSc and MSc levels.