The Synthesis of Bio-derived, Novel Cyclic Organic Carbonates

通过几种方法合成甘油碳酸酯已被广泛综述，1-3这证实了它是一种具有高度兴趣和潜在价值的分子。甘油碳酸酯价值的一个重要因素是，它是一种可行的途径，可以升级生物柴油生产中的废甘油。已经证明的甘油碳酸酯的兴趣、价值和应用是本项目中从其他糖醇合成环状碳酸酯的兴趣的驱动因素。本文将研究由糖原料通过简单的氢化反应合成的新型环状碳酸酯的合成和应用。该项目的出发点是来自该小组的未发表的工作，该工作表明，环状碳酸酯可以通过糖醇与尿素，碳酸二甲酯或羰基二咪唑的反应合成，在化学或酶催化的路线或没有催化。然而，这些反应中的每一种都有其优点和缺点，因此比较反应类型将允许确定最佳方法。工作的目的是设计反应方法，这将允许选择性合成的环状碳酸酯，通过所有上述路线。由于这些是新型化合物，没有可用的标准品，第一步将是设计反应和纯化以得到这些碳酸盐标准品，这些标准品需要进行充分表征（NMR、CHN、质谱、FTIR）。然后，这些标准品可用于鉴定可能有多种产物的合成反应产物（例如，与尿素的反应可能具有较低的选择性），并用于探索潜在的应用，如聚合反应。一旦确定了获得标准品的可靠途径，将开发使用更可持续试剂的反应方法。先前的工作已经表明，这些反应可能具有降低的选择性，因此仔细设计反应、选择催化剂、条件和试剂比率以使所需碳酸酯的产率最大化将是重要的。将探索温度和不同催化剂/酶的影响。也有可能在减压下进行反应，并原位生成产物，这对于未来的工业合成将是极好的。然后可以在产率、选择性、效率和“绿色”证书方面比较路线以确定环状碳酸酯的最佳路线。参考文献：1. Christy，S.; Noschese，A.; Lomeli-Rodriguez，M.; Greeves，N.;洛佩斯-桑切斯，J. A.，甘油碳酸酯的合成及应用研究进展。Current Opinion in绿色和可持续化学2018，14，99-107.2。Sonnati，M.的O.; Amigoni，S.; Taffin de Givenchy，E. P的; Darmanin，T.; Choulet，O.; Guittard，F.，甘油碳酸酯作为未来的多功能结构单元：合成、反应性、性能和应用。绿色化学2013，15（2），283-306.3. Ochoa-Gómez，J. R.; Gómez-Jiménez-Aberasturi，O.; Ramirez-López，C.; Belsué，M.，绿色化学品甘油碳酸酯的工业替代方法简述。有机工艺研究与开发2012，16（3），389-399。

The synthesis of glycerol carbonate via several methods has been reviewed extensively, 1-3 which confirms that it is a molecule of high interest and potential value. A large factor in the value of glycerol carbonate, is that it is a viable route to upgrade otherwise waste glycerol from biodiesel production. The interest, value, and applications which have already been demonstrated for glycerol carbonate is the driving factor in the interest in the synthesis of cyclic carbonates from other sugar alcohols in this project. The synthesis and applications of novel cyclic carbonates from other polyols, which can be readily derived from sugar-feedstocks by a simple hydrogenation of the corresponding sugar will be studied. The starting point for the project is the unpublished work from within the group which has shown that cyclic carbonates can be synthesised by reactions of sugar alcohols with urea, dimethyl carbonate or carbonyl diimidazole, in chemical or enzyme catalysed routes or without catalysis. Each of these reactions has its benefits and its drawbacks, however, so comparing between the reaction types will allow for the optimum method to be determined. The aim of the work is to design reaction methods which will allow for selective synthesis of the cyclic carbonates, by all the above routes. As these are novel compounds, with no standards available, the first step will to be design a reaction and purification to give these carbonate standards, which will need to be fully characterised (NMR, CHN, Mass spec, FTIR). These standards can then be used for identification of reaction products from synthesis where multiple products are possible (e.g. reactions with Urea which can have lower selectivity), and for exploring potential applications such as polymerisation reactions. Once a reliable route to standards has been identified, reaction methods using more sustainable reagents will be developed. Previous work has shown that these reactions can have reduced selectivity, so it will be important to design the reactions carefully, chose catalysts, conditions, and reagent ratios to maximise the yield of the desired carbonates. The effect of temperature and different catalysts/enzymes will be explored. There is also the possibility, to carry out the reaction under reduced pressure, and distil products in-situ, which would be excellent for future industrial synthesis. The routes can then be compared in terms of yield, selectivity, efficiency and 'green' credentials to determine the optimum route to the cyclic carbonates. References:1. Christy, S.; Noschese, A.; Lomeli-Rodriguez, M.; Greeves, N.; Lopez-Sanchez, J. A., Recent progress in the synthesis and applications of glycerol carbonate. Current Opinion in Green and Sustainable Chemistry 2018, 14, 99-107.2. Sonnati, M. O.; Amigoni, S.; Taffin de Givenchy, E. P.; Darmanin, T.; Choulet, O.; Guittard, F., Glycerol carbonate as a versatile building block for tomorrow: synthesis, reactivity, properties and applications. Green Chemistry 2013, 15 (2), 283-306.3. Ochoa-Gómez, J. R.; Gómez-Jiménez-Aberasturi, O.; Ramirez-López, C.; Belsué, M., A Brief Review on Industrial Alternatives for the Manufacturing of Glycerol Carbonate, a Green Chemical. Organic Process Research & Development 2012, 16 (3), 389-399.