Behr Arno, Leschinski Julia, Awungacha Colin, Simic Suzana, Knoth Tanja
Department of Biochemical and Chemical Engineering, Technische Universität Dortmund, Dortmund, Germany.
ChemSusChem. 2009;2(1):71-6. doi: 10.1002/cssc.200800197.
Owing to the large amount of glycerol that is formed as a by-product during biodiesel production, there have been great efforts to develop new reactions and processes based on glycerol as a renewable feedstock. One example is the telomerization of butadiene with glycerol which provides an atom-economic route to amphiphilic molecules. The reaction is catalyzed by homogeneous palladium catalysts which necessitates efficient catalyst recycling. By employing an aqueous biphasic system, an increased selectivity towards the desired mono-ethers was observed in the telomerization reaction. The performance of the reaction and separation and recycling of the catalyst were optimized by the addition of organic solvents as well as cyclodextrins. By adding cyclodextrins, the conversion of glycerol could be increased and the leaching of palladium could be reduced. Leaching of palladium into the organic phase could be lowered also by using 2-octanol or 2-propanol as additional solvents. Furthermore, the catalyst system could be stabilized by adding nitriles or phosphonium salts, and radical polymerization, which leads to fouling, could be inhibited successfully.
由于在生物柴油生产过程中会产生大量作为副产物的甘油，人们付出了巨大努力来开发基于甘油作为可再生原料的新反应和工艺。一个例子是丁二烯与甘油的调聚反应，该反应为合成两亲性分子提供了一条原子经济路线。该反应由均相钯催化剂催化，这就需要高效的催化剂循环利用。通过采用双水相体系，在调聚反应中观察到对所需单醚的选择性提高。通过添加有机溶剂以及环糊精，优化了反应性能以及催化剂的分离和循环利用。通过添加环糊精，可以提高甘油的转化率并减少钯的浸出。使用2-辛醇或2-丙醇作为额外溶剂也可以降低钯向有机相中的浸出。此外，通过添加腈或鏻盐可以稳定催化剂体系，并且可以成功抑制导致结垢的自由基聚合反应。
