Optical tweezing for bio refining applications

每年，在生物质中发现的约1300亿公吨碳水化合物中，目前只有约4%被利用。生物质中的甘油三酯可以与甲醇反应形成生物柴油，这是一种生物可再生能源，有可能成为替代传统化石燃料和减少二氧化碳排放的有前途的候选者。在生物柴油的合成中，甘油作为副产物产生，并且由于近年来生物柴油产量的快速增加而大量产生。因此，这是有用的，以开发有效的方法，甘油进一步反应，使更有价值的副产品，这些反应需要一种催化剂。本研究的重点是通过开发一种有效的固体催化剂用于反应中的生物质高效转化为生物柴油。在该反应中使用固体催化剂是有利的，因为它可以在完成时容易地从反应混合物中分离。然后，固体催化剂可以被洗涤并在进一步的生产中重复使用，使该过程更有效。这将降低生产成本和反应产生的废物。此外，典型的生物柴油生产和使甘油增值的反应是大规模进行的，这有利于按比例放大反应、产物和副产物。然而，当大量使用反应物时，由于平均效应，反应的动力学和动力学更难以详细检查。相比之下，通过使用fL-pL体积液滴的光学镊子，可以在分子水平上研究反应，并揭示转化的化学动力学。光学镊子利用高度聚焦的激光将液滴保持在远离可能影响行为和反应动力学的表面的受控环境中。保持在光镊中的反应物的液滴然后可以被聚结，并且随着反应的进行而在真实的时间中研究反应的动力学。光镊与拉曼光谱相结合，以量化液滴的性质，并在整个反应过程中破碎和形成时识别条带。3D打印将用于设计光学镊子室，用于在受控环境中控制和量化液滴化学反应。具有特定功能和入口的腔室部件将进行优化，以有效分析不同阶段的颗粒。这项研究将集中在生物柴油的合成以及两个反应，以稳定甘油，这些反应都涉及两个独立的液相（油，生物质或甘油和所使用的液体反应物）以及固相（催化剂）。这种复杂的分析意味着需要优化镊子腔室，以克服分析三个相互作用的相的固有问题，并避免吸入任何正在使用的反应物。这项研究的动机来自于希望了解生物柴油合成反应和甘油增值反应的基本化学和动力学。通过在分子水平上研究这些反应的动力学，将深入了解每种催化剂的效率。可以开发新的催化剂并使其功能化以优化反应。生物燃料合成是一个很有前途的研究领域，可以解决目前与使用化石燃料有关的气候问题。为这些反应开发高效、低成本的催化剂是使生物柴油合成可行和可持续的关键。通过研究生物柴油合成副产物（甘油）的反应，并优化这些反应中使用的催化剂，生物柴油合成将变得更有效。从反应副产物衍生的化合物将比甘油更有用和有价值。

Every year only about 4% of approximately 130 billion metric tons of carbohydrates found in biomass are currently utilised. Triglycerides in biomass can be reacted with methanol to form biodiesel, a bio-renewable source of energy that has the potential to be a promising candidate for the replacement of traditional fossil fuels and reduce CO2 emissions. In the synthesis of biodiesel, glycerol is produced as a by-product and is being produced in significant amounts due to the rapid increase in biodiesel production over recent years. It is therefore useful to develop efficient ways to react glycerol further to make more valuable by-products and these reactions require a catalyst.This research focuses on the efficient conversion of biomass to biodiesel by developing an effective solid catalyst for use in the reaction. The use of a solid catalyst in this reaction is advantageous as it can be easily separated from the reaction mixture upon completion. The solid catalyst can then be washed and reused in further production, making the process more efficient. This will reduce both production costs and the waste produced by the reaction. Furthermore, typical biodiesel production and the reaction to valorise glycerol are carried out on large scales, which is advantageous in scaling up reactions, products and by-products. However, when reactants are used in large volumes the kinetics and dynamics of the reaction are more challenging to examine in detail due to averaging effects. In comparison by using optical tweezing of fL - pL volume droplets the reaction can be studied on a molecular level and the chemistry kinetics of transformation revealed.Optical tweezing utilises highly focussed laser light to hold droplets in a controlled environment away from surfaces that could impact behaviour and reaction dynamics. Droplets of reactants held in the optical tweezers can then be coalesced and the kinetics of the reaction studied in real time as the reaction proceeds. Optical tweezers are combined with Raman spectroscopy to quantify the properties of droplets and identify bands as they are broken and formed throughout the reaction. 3D printing will be used to design an optical tweezing chamber for controlling and quantifying droplet chemical reactions in a controlled environment. Chamber parts with specific features and inlets will be optimised for an efficient analysis of particles in different phases undergoing reactions. This research will focus on the synthesis of biodiesel as well as two reactions to valorise glycerol, these reactions all involve two separate liquid phases (an oil, biomass or glycerol and the liquid reactant used) as well as a solid phase (the catalyst). This complex analysis means the tweezing chamber needs to be optimised to overcome the inherent issues of analysing three interacting phases and to avoid inhalation of any of the reactants being used.The motivation for this research comes from the desire to understand the fundamental chemistry and kinetics of the synthesis reaction of biodiesel and the reactions to valorise glycerol. By studying the dynamics of these reactions on a molecular level insight will be gained into how efficient each respective catalyst is. New catalysts can be developed and functionalised to optimise the reaction. Biodiesel synthesis is a promising area of research to address current climate concerns relating to the use of fossil fuels. Developing efficient, cost effective catalysts for these reactions is essential to make biodiesel synthesis viable and sustainable. By studying reactions to valorise the by-product of the biodiesel synthesis (glycerol) and optimising the catalysts used in these reactions the biodiesel synthesis will be made more efficient. The compounds derived from the reactions by-product will be far more useful and valuable than glycerol.