PhD Scholarship Production of biobased solvents form lignocellulosic biomass

Thursday, March 28, 2019

This project will develop a chemical process for producing a bio-solvent, known as nonanone, from levulinic acid. Nonane will replace petroleum-derived solvents such as hexane and octane in chemical process industries. Under conventional chemistry the production of nonanone from levulinic acid would involve the consumption of fossil fuel derived hydrogen, however, a key novel aspect of this project will be the use of our biomass-derived formic acid as a hydrogen donor to substitute for molecular hydrogen enhancing the sustainability of the process.

This work will initially involve catalyst identification and selection. This will require an initial screening of a wide range of catalytic materials including metal oxides by testing them under the standard condition for levulinic acid hydrogenation to both gVL and pentanoic acid using HCOOH as the hydrogen donor. The reactions will be undertaken in high-pressure Parr reactors and the products quantified using ion-chromatography for conversion and selectivity. The best catalysts will be characterised for their chemical composition and structural morphology (XRD, XPS, TEM). The optimum catalyst will undergo a series of tests where the reaction variable such as temperature, pressure, catalyst loading and the ratio of formic acid: levulinic acid will be varied. The reaction profiles will be monitored continuously with time and kinetic modelling of the data obtained will be used to identify the reaction mechanism. The catalyst will be tested in both aqueous and biphasic media incorporating an aqueous and organic phase. The influence of the acidity of the catalyst and solvent will be determined.

The cerium zirconia catalysts will be prepared by both wet impregnation and co-precipitation methods. The Ce loading and calcination temperature will be varied and the catalysts tested for vapour phase ketonisation. The catalysts will be characterised pre-testing using XRD, BET, and XPS while post tested catalysts will also undergo FT-Raman spectroscopy to identify residual organic contaminants. The catalysts will be tested in a PID high-pressure gas flow reactor with in-line gas chromatography to analyse for pentanoic acid consumption and product formation. The reaction condition that will be investigated includes catalyst loading, H2 concentration, temperature and pressure. The conversion and selectivity of the catalyst will be determined. Catalyst reuse will be assessed for deactivation.

BSc (2.1 minimum) or preferably MSc in Chemistry or Chemical Engineering

Stipend of €18,000 tax-free per annum, EU tuition fees covered. Non-EU students may have to pay balance of full fees.
Tuesday, April 16, 2019

Professor J J Leahy, Dept of Chemical Sciences, University of Limerick email: j.j.leahy@ul.ie

The pharmaceutical and fine chemical industry recognises that solvents account for the majority of the waste produced in a typical batch process. There are also regulatory and compliance issues regarding safe solvent use and disposal. There is an established acknowledged need to reduce hazardous solvent use and find benign substitutes, and this is the focus of this proposal. The proposal aims to develop a process for the production of a sustainable bio-based solvent from biomass to substitute for conventional organic solvents, reducing the environmental impact of industrial processes as well as making them safer. Biomass such as wood or straw comprises three main chemical components, cellulose, lignin and hemicellulose. Under relatively mild conditions the cellulose can be converted into levulinic acid and formic acid which are known as platform chemical molecules. Platform chemicals are molecules which can be used to manufacture a very wide range of commodity chemicals such as pharmaceutical active ingredients or agrochemicals. Levulinic acid is a key chemical bridge connecting biomass and petroleum processing and is listed amongst the ten most important target chemicals by the US-DOE biomass programme.

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