Ptaszyńska Karolina, Malaika Anna, Kozigrodzka Klaudia, Kozłowski Mieczysław
Faculty of Chemistry, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 8, 61-614 Poznań, Poland.
Molecules. 2023 Sep 9;28(18):6534. doi: 10.3390/molecules28186534.
The results of sustainable and selective synthesis of glycerol carbonate (GC) from urea and glycerol under ambient pressure using carbon-fiber-supported metal oxide catalysts are reported. Carbon fibers (CF) were prepared via a catalytic chemical vapor deposition method (CCVD) using Ni as a catalyst and liquefied petroleum gas (LPG) as a cheap carbon source. Supported metal oxide catalysts were obtained by an incipient wetness impregnation technique using Zn, Ba, Cr, and Mg nitrates. Finally, the samples were pyrolyzed and oxidized in an air flow. The obtained catalysts (10%MeO/CF) were tested in the reaction of urea glycerolysis at 140 °C for 6 h under atmospheric pressure, using an equimolar ratio of reagents and an inert gas flow for NH removal. Under the applied conditions, all of the prepared catalysts increased the glycerol conversion and glycerol carbonate yield compared to the blank test, and the best catalytic performance was shown by the CF-supported ZnO and MgO systems. Screening of the reaction conditions was carried out by applying ZnO/CF as a catalyst and considering the effect of reaction temperature, molar ratio of reagents, and the mode of the inert gas flow through the reactor on the catalytic process. Finally, a maximum yield of GC of about 40%, together with a selectivity to glycerol carbonate of ~100%, was obtained within 6 h of reaction at 140 °C using a glycerol-to-urea molar ratio of 1:1 while flowing Ar through the reaction mixture. Furthermore, a positive heterogeneous catalytic effect of the CF support on the process was noticed.
报道了在常压下使用碳纤维负载的金属氧化物催化剂由尿素和甘油可持续且选择性合成碳酸甘油酯（GC）的结果。碳纤维（CF）通过催化化学气相沉积法（CCVD）制备，使用Ni作为催化剂，液化石油气（LPG）作为廉价碳源。负载型金属氧化物催化剂通过初湿浸渍技术使用Zn、Ba、Cr和Mg的硝酸盐获得。最后，样品在气流中进行热解和氧化。所制备的催化剂（10%MeO/CF）在140℃、常压下进行尿素甘油解反应6小时，使用等摩尔比的试剂和惰性气体流以除去NH进行测试。在所应用的条件下，与空白试验相比，所有制备的催化剂均提高了甘油转化率和碳酸甘油酯产率，CF负载的ZnO和MgO体系表现出最佳的催化性能。以ZnO/CF作为催化剂，考虑反应温度、试剂摩尔比以及惰性气体流经反应器的方式对催化过程的影响，进行了反应条件的筛选。最后，在140℃反应6小时内，使用甘油与尿素的摩尔比为1:1，同时使Ar流经反应混合物，获得了约40%的GC最大产率以及对碳酸甘油酯约100%的选择性。此外，还注意到CF载体对该过程具有积极的多相催化作用。
