Fuel from biorenewable polyols: A new catalytic route

有限的化石燃料资源、不断扩大的全球人口以及对提高生活水平的渴望，将需要更高效、更环保的化工原料路线。化学工业面临着向更良性试剂、消除有毒副产品和从不断减少的自然资源中提高效率的挑战，同时也在探索可再生资源。解决所有这些问题的一种方法是开发有效的催化过程，将低价值的废物流转化为更有用和有价值的化学产品。使用生物可再生原料部分替代化石原料的一个例子是生物柴油的生产。这需要从植物或动物中提取甘油三酯和其他脂肪物质，并与甲醇反应。所使用的甲醇来源于不可持续的化石燃料资源。该工艺生产出高质量的生物柴油，同时产生甘油作为废物。通常以质量为基础，10吨生物柴油产生1吨甘油作为不希望的副产品。废弃甘油被氢氧化钠和未转化脂肪严重污染。因此，目前的废甘油流只能作为低效率的低品位燃料使用，并且代表了一个主要的环境问题，阻碍了生物柴油生产的未来扩张。已经进行了大量的研究，致力于寻找废甘油在商业上可行的用途，用一种简单而有效的方法将其转化为有用的化学品和燃料，具有巨大的潜力，可以产生经济、环境和社会影响。这项工作试图建立在我们最近的一项发现之上。我们已经确定了简单的金属氧化物催化剂（MgO和CeO2）对于从生物可再生甘油合成甲醇和其他工业上重要的中间体非常有效。这种新的绿色技术代表了甲醇制造的潜在范式转变。目前甲醇的生产采用两步法，需要大规模生产才能达到必要的效率。甲醇是一种主要的商品化学品，目前全球年产量超过5000万吨。利用绿色环保的反应条件开发新的一步法具有相当大的潜力。在温和的反应条件下，可以实现将含水甘油转化为甲醇和其他化学品，但需要逐步改变以扩大这种化学反应的范围并提高产品收率。重要的是，不需要额外的氢，因为水作为氢转移试剂。此外，该工艺可以直接使用来自生物柴油源的粗甘油流，并且避免了昂贵的净化要求。我们将以一种综合的方法结合实验和理论研究，对我们最近发现的新催化化学进行详细的基础理解。理论有可能指导实验研究，并提供对新催化剂和过程的基本理解，但当理论与实验计划紧密结合时，这种方法是最有效的。实现对化学的详细基本理解将有助于改进催化剂和技术的发展。实验方法将基于我们在催化剂设计方面的经验和专业知识。它将结合稳态和瞬态研究来评估催化剂的性能，并阐明反应机理的关键步骤。详细的催化剂表征，包括非原位和原位，将提供催化剂结构和化学性质的基本信息。一旦建立了结构活性关系，我们将利用我们的专业知识来设计具有可控组成，形态和结构的催化剂。

Limited fossil fuel resources, an expanding global population and a desire for improved living standards will require ever more efficient and environmentally friendly routes to our chemical feedstocks. The chemical industry faces the challenge of moving towards more benign reagents, eliminating toxic by-products and increasing efficiency from an ever decreasing set of natural resources, while also exploring renewable ones. One way to address all of these concerns is to develop efficient catalytic processes that convert low value waste streams into more useful and valuable chemical products.An example of a process using a bio-renewable feedstock to partially replace a fossil source is biodiesel manufacture. This takes triglycerides and other fatty materials, derived from plant or animal sources, and reacts them with methanol. The methanol used is derived from nonsustainable fossil fuel resources. The process produces high quality biodiesel, together with glycerol as a waste product. Typically on a mass basis 10 tons of biodiesel produces 1 ton of glycerol as an undesired by-product. Waste glycerol is highly contaminated with sodium hydroxide and unconverted fats. Hence, presently the waste glycerol stream only has use as an inefficient low grade fuel, and represents a major environmental problem that keeps a brake on the future expansion of biodiesel production. There has been much research dedicated to finding commercially viable uses for waste glycerol, with a simple and efficient process for conversion to useful chemicals and fuels offering significant potential to deliver economic, environmental and societal impact. This works seeks to build on one of our recent discoveries. We have identified that simple metal oxide catalysts (MgO and CeO2) are very effective for the synthesis of methanol and other industrially important intermediates from bio-renewable glycerol. This new green technology represents a potential paradigm shift in the manufacture of methanol. At present methanol is produced by a two-step process requiring large scale to achieve the necessary efficiency. Methanol is a major commodity chemical, and today over 50 Mt pa are produced globally. There is considerable potential in the development of a new one step process using green environmentally sound reaction conditions. Aqueous glycerol conversion into methanol and other chemicals, using mild reaction conditions, can be achieved, but a step change is required to broaden the scope of this chemistry and improve product yield. Importantly additional hydrogen is not required as water acts as a hydrogen transfer reagent. Furthermore, the process can operate using a crude glycerol stream directly from a biodiesel source, and the requirement for expensive purification circumvented.We will combine experimental and theoretical studies in an integrated approach, to develop a detailed fundamental understanding of the new catalytic chemistry we have recently discovered. Theory has the potential to guide experimental studies and also deliver fundamental understanding of new catalysts and processes, but this approach is most effective when theory is embedded within an experimental programme with both strands working closely together. Achieving a detailed fundamental understanding of the chemistry will support development of improved catalysts and technology. The experimental approach will build on our experience and expertise of catalyst design. It will use a combination of steady-state and transient studies to evaluate catalyst performance and elucidate key steps in the reaction mechanism. Detailed catalyst characterisation, both ex situ and in situ, will provide essential information on catalyst structure and chemical properties. Once structure activity relationships are established, improved catalysts will be designed making use of our expertise in preparing catalysts with controlled composition, morphology and structure.