Optical tweezing for bio refining applications

每年，在生物质中发现的约1300亿吨碳水化合物中，目前仅利用了约4%。生物质中的甘油三酯可以与甲醇反应形成生物柴油，生物柴油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希望的候选能源。在生物柴油的合成过程中，甘油是作为副产品产生的，由于近年来生物柴油产量的快速增长，甘油的产量正在显著增加。因此，开发有效的方法进一步反应甘油以产生更多有价值的副产物是有用的，这些反应需要催化剂。本研究的重点是通过开发一种有效的固体催化剂来有效地将生物质转化为生物柴油。在这个反应中使用固体催化剂是有利的，因为它在完成后可以很容易地从反应混合物中分离出来。然后，固体催化剂可以清洗并在进一步的生产中重复使用，从而提高了工艺效率。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甘油增值反应是在大规模进行的，这有利于扩大反应、产物和副产物的规模。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，利用光学镊子对fL - pL体积液滴进行分析，可以在分子水平上对反应进行研究，揭示了转化的化学动力学。光学镊子利用高度聚焦的激光将液滴保持在受控环境中，远离可能影响行为和反应动力学的表面。然后，在光镊中保持的反应物液滴可以合并，并且随着反应的进行，可以实时研究反应的动力学。光学镊子与拉曼光谱相结合，量化液滴的特性，并识别在整个反应过程中它们被破坏和形成的条带。3D打印将用于设计一个光学镊子室，用于在受控环境中控制和量化液滴的化学反应。具有特定特征和入口的腔室部件将被优化，以有效分析处于不同反应阶段的颗粒。这项研究将集中于生物柴油的合成以及使甘油挥发的两种反应，这些反应都涉及两种不同的液相（油、生物质或甘油和所用的液体反应物）以及固相（催化剂）。这种复杂的分析意味着需要优化镊子室，以克服分析三个相互作用相的固有问题，并避免吸入任何所用的反应物。这项研究的动机来自于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的愿望。通过在分子水平上研究这些反应的动力学，我们将了解到每种催化剂的效率。新的催化剂可以开发和功能化，以优化反应。生物柴油合成是一个很有前途的研究领域，可以解决当前与化石燃料使用有关的气候问题。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。通过研究使生物柴油合成副产物（甘油）增值的反应，并优化这些反应中使用的催化剂，生物柴油的合成将更加有效。从反应副产物中得到的化合物将比甘油有用和有价值得多。

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.