Synthesis of jet fuel range high-density polycycloalkanes with vanillin and cyclohexanone
Synthesis of jet fuel range high-density polycycloalkanes with vanillin and cyclohexanone
复制标题
香草醛和环己酮合成喷气燃料系列高密度多环烷烃
DOI：
10.1039/d1se01732b
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发表时间：
2022-02-15
影响因子：
5.6
通讯作者：
Li, Ning
中科院分区：
文献类型：
--
作者：
Gao, Haofei;Han, Fengan;Li, Ning
在这项工作中，首先用香草醛和环己酮这两种源自木质素的平台化合物，通过两步法合成了喷气燃料系列高密度多环烷烃、二环己基甲烷和十二氢芴。第一步，通过香草醛和环己酮在一系列二氧化钛基纳米材料催化剂上进行酸催化羟醛缩合反应，得到2-(4-羟基-3-甲氧基亚苄基)环己烷-1-酮，一种喷气燃料系列C-13多环烷烃前体。其中，硫酸化二氧化钛纳米纤维（STNFs）表现出最高的活性。相比之下，在423 K下反应10 h后，得到了高产率（81%）的2-(4-羟基-3-甲氧基亚苄基)环己烷-1-酮。根据表征结果，STNF催化剂的良好性能可归因于其较高的酸强度和较高的布朗斯台德与路易斯酸位比。随后，羟醛缩合产物在Pd/C和H-Y沸石的共催化下通过加氢脱氧(HDO)进一步转化为二环己基甲烷和十二氢芴的混合物。根据我们的测量，HDO工艺得到的环烷混合物具有较高的密度(0.95 g mL(-1))和较低的凝固点(256 K)。作为一种潜在的应用，它可以混合到低凝固点喷气燃料中以提高其体积热值。
In this work, jet fuel range high-density polycycloalkanes, dicyclohexylmethane and dodecahydrofluorene, were first synthesized by a two-step method with vanillin and cyclohexanone, two platform compounds that can be derived from lignin. In the first step, 2-(4-hydroxy-3-methoxybenzylidene)cyclohexan-1-one, a jet fuel range C-13 polycycloalkane precursor, was obtained through an acid-catalyzed aldol condensation reaction between vanillin and cyclohexanone over a series of titanium dioxide based nanometer material catalysts. Among them, sulfated titania nanofibers (STNFs) exhibited the highest activity. Over them, a high yield (81%) of 2-(4-hydroxy-3-methoxybenzylidene)cyclohexan-1-one was obtained after the reaction was carried out at 423 K for 10 h. On the basis of the characterization results, the good performance of the STNF catalyst can be attributed to its higher acid strength and higher Bronsted to Lewis acid site ratio. Subsequently, the aldol condensation product was further converted to a mixture of dicyclohexylmethane and dodecahydrofluorene by hydrodeoxygenation (HDO) under the co-catalysis of Pd/C and H-Y zeolite. According to our measurement, the cycloalkane mixture as obtained from the HDO process has a higher density (0.95 g mL(-1)) and lower freezing point (256 K). As a potential application, it can be blended into low freezing point jet fuels to improve their volumetric heat values.