5-hydroxymethylfurfural (HMF) is a versatile renewable base chemical, which can be produced by the acid-catalyzed dehydration of fructose. At this time HMF cannot yet compete with oil-based analogues, such as p-xylene, due to the high costs of production. Future incentives to encourage the transition to a bio-based economy may increase the feasibility of investing in a HMF production process, but only if an efficient and cost-effective production method is designed. Previous research showed promising results using a reactive extraction unit. However, the selection of the organic solvent has a large influence on both the overall yield, as well as on the energy requirements in the final recovery of the HMF in a subsequent separation step. In this work, an intrinsically better, but hard to separate solvent, tri-butyl phosphate (TBP), was compared to methyl isobutyl ketone (MIBK), a solvent which is easy to separate from the HMF by distillation. The chosen method of separation for the TBP-HMF reaction mixture is back-extraction, using an anti-solvent to transfer the HMF back to an aqueous phase. By using backextraction, it was possible to lower the energy (steam) requirements of a TBP-based process under the benchmark calculated for a MIBK-based process by 18%. A drawback of the TBP-based process is its increased complexity, leading to higher capital costs. A model was developed to assess the balance between reduced steam demands and increased capital and operational costs. It was found that even if an optimistic scenario for the effectiveness of the anti-solvent was used, the MIBK-based process was superior across nearly all key performance indicators. Most indicative of the relative feasibility is the minimum selling price of HMF (at a production of 20 kton/year), which is €1.85/kg or €1.64/kg, for a TBP- and MIBK-based process respectively. The only area where the TBP-based process performs slightly better is sustainability, with calculated emissions of 1.90 kgCO2eq/kg HMF compared to 1.97 kgCO2eq/kg HMF for a MIBK-based process.

Crystallization is employed in a wide range of industries but our ability to control it remains far from perfect. New methods are being continuously developed and improved to provide enhanced kinetics and control. Non-photochemical laser induced nucleation (NPLIN) is one of the avenues being looked into extensively since its accidental discovery about two decades ago. Despite providing improved nucleation kinetics and potential polymorph control, the mechanism behind NPLIN is still unknown. Four different theories have been proposed in the literature with varying amounts of agreement between
different research groups.
The main aim of this thesis is to try to determine the mechanism behind NPLIN. This report can be divided into two parts, each focusing on a possible mechanism. The first is the optical Kerr effect,
which involves investigating the effect of polarization of light on glycine polymorph formed. This is achieved by varying the laser light polarisation and number of pulses for a range of glycine
supersaturation. The second part deals with an experimental setup designed to work with microscale volumes. This will give us the capability to isolate the nuclei and observe the events leading up to their formation.
For studying the optical Kerr effect, the experiment performed by Sun et al. was repeated. A significant temperature increase inside the solution was obtained because of exposure to a high number
of pulses (600) of infrared light. No dependence of laser light polarization on polymorph formation was found. The polymorph formed by laser is different than that obtained by crash cooling. In the
second part of the thesis, the attention is shifted towards the role of impurities present in the solution which can also absorb the laser light leading to formation of a cavitation bubble. This possibility was
examined with the help of the setup mentioned above. It was noted that the crystals were nucleating at multiple points around the laser focus at a distance which is similar to the size of the cavitation bubble previously reported in literature. These observations made can be attributed towards the presence of a bubble.