高密度燃料三环戊二烯加氢反应历程

Hydrogenation of tricyclopentadiene to prepare high-energy-density fuel:reaction pathway

三环戊二烯(TCPD)的加氢产物是具有重要应用价值的高密度碳氢燃料,本文对三环戊二烯的加氢反应过程进行了研究。采用气质联用、红外光谱和核磁共振对加氢产物进行表征,发现在加氢反应中TCPD的降冰片烯(NB)双键首先被饱和,生成中间产物12,13-二氢三环戊二烯(12,13-DHTCPD),残留的环戊烯(CP)双键需要在更高的温度和氢压下反应生成四氢三环戊二烯(THTCPD),即反应按照TCPD→12,13-DHTCPD→THTCPD的途径进行。利用密度泛函理论中的B3LYP/6-31G*方法对加氢过程进行模拟,证实TCPD中NB双键比CP双键更活泼,反应活性更高,并且NB双键加氢产物比CP双键加氢产物在热力学上更稳定,因此反应中NB双键优先反应,从理论上证实了实验结果。研究为三环戊二烯的两段加氢工艺提供了理论依据。

The hydrogenated product of tricyclopentadiene （TCPD） is a potential high-energy-density fuel. The hydrogenation pathway of TCPD was investigated to understand the reaction process. The reaction intermediate and final products were characterized by using GC-MS, IR, 1H NMR and 13C NMR. The double bond in norbornene ring （NB bond） of TCPD was easily saturated at a low temperature, and an intermediate 12, 13-dihydrotricyclopentadiene （12, 13-DHTCPD） was formed. Higher temperature and hydrogen pressure were required for the saturation of remaining double bond in cyclopentene ring （CP bond） to generate a completely hydrogenated compound tetrahydrotricyclopentadiene （THTCPD） . That is to say, the reaction occurred via the TCPD→12, 13-DHTCPD→THTCPD route. To clarify the reactivity of double bonds in TCPD molecules, a DFT calculation at B3LYP/6-31G^＊ level was conducted by using Gaussian 03 series programs. The bond parameters confirmed that the NB double bond was more reactive than the CP bond. Total energy calculation also showed that 12, 13-DHTCPD was preferred in thermodynamics, compared with another possible intermediate 5,6-DHTCPD. The computational result was in good agreement with the experiments. This work provides fundamental information for the two-step hydrogenation operation of TCPD.