New catalytic routes towards CO2-derived polymer materials

Lead Research Organisation: University of Edinburgh
Department Name: Sch of Chemistry

Abstract

The project aims to develop and understand novel organometallic catalysts to make sustainable materials from CO2, providing an exciting opportunity to establish a new area of research. You will be provided with high-level training across a wide range of areas including:
Air-sensitive organometallic synthesis and characterisation (including the use of Schlenk techniques, gloveboxes and NMR spectroscopy)
Polymer synthesis and characterisation (high pressure autoclaves, GPC, mass spectrometry)
Mechanistic understanding for targeted catalyst development

Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/N509644/1 01/10/2016 30/09/2021
1939290 Studentship EP/N509644/1 01/09/2017 28/02/2021 Anand Gaston
 
Description My research projects centre on the design and testing of new monometallic and bimetallic 'salen' complexes with cooperative metal properties to both better understand bimetal synergy and to produce biopolymers with competitive plastic properties. The initial work focused on the synthesis and characterisation of new aluminium - salen type complexes modified with amine functional groups to introduce increased electron density at the metal centre, which is active towards polymerisation.These new complexes have since been shown to be highly active towards the ring opening polymerisation of rac-lactide and are currently the fastest Al-Cl system known for this type of polymerisation. Further, these type of Al-Cl complexes have historically required the use of an onium salt co-catalyst to function, reducing the atom economy and increasing the cost of the polymerisation. The incorporation of amine functional groups reduced the Lewis acidity of the aluminium which increased the rate of polymer initiation and circumvented the need for the co-catalyst producing a more efficient process.
Following this work, the synthesis and characterisation of another modified salen complex was achieved, this time containing carboxylic acid functional groups. These complexes contained two, rather than one, metal binding pockets, allowing for the incorporation of two metals within close proximity in the same ligand scaffold. This complex allowed for the simultaneous production of an environmentally friendly polymer with a controlled microstructure while also providing a practical means to investigate cooperative intra-complex metal effects.The combination of aluminium with a heterometal (zinc or magnesium) within these complexes is very promising, showing up to x10 improvement of the polymerisation rate relative to the monometallic analogue.
The next generation of complexes are set to include the modification of the salen ligand with an ester functional group. Preliminary studies with the monometallic Al-Cl system have demonstrated increased polymerisation rate in comparison with the monometallic carboxylic acid system.
Exploitation Route The metals incorporated within the carboxylic acid and ester salen systems are, as of yet, very limited and the combination of other metals may yield systems with far greater reactivity. Further, these complexes have only been screened for reactivity with lactide, while these complexes are of potential interest for a variety of co-polymerisations and small molecule transformations.
Sectors Chemicals,Environment,Manufacturing, including Industrial Biotechology
 
Description Chemistry Open Day 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact 630 visitors attended an open doors day hosted within the School of Chemistry. A rotation of different activities and information sessions were put on with a variety of topics and research areas which reflected the research areas within the University of Edinburgh. An experiment involving gaviscon to make 'worms' was used as an example of the polymerisation process, providing a child friendly introduction to the chemistry done in the Garden group. The annual open day was the most successful to date, attracting the largest volume of visitors thus far.
Year(s) Of Engagement Activity 2018