钴对高硫合成气制甲硫醇负载型钼酸钾催化剂的促进作用

The Study of the Promotion of Co to the Supported Catalyst K_2MoO_4 for the Syntheses of Methanthiol from H_2S-Containing Syngas

在不同载体的K2MoO4催化剂上高硫化氢合成气合成甲硫醇活性大小顺序为:SiO2>AC>CNTs>Al2O3;3种氧化物助剂对K2MoO4/SiO2催化剂的活性促进作用的大小顺序为:CoO>NiO2>Fe2O3;m(K2MoO4)∶m(CoO)∶m(SiO2)=5∶1∶20,催化剂生成甲硫醇得率为0.76g·h-1·g-1cat,比m(K2MoO4)∶m(SiO2)=1∶20催化剂高约1 5倍,两种催化剂的表观活化能分别为53.6kJ·mol-1和83.5kJ·mol-1.从ESR表征可观测到氧包围的"oxo Mo(V)"(g=1.93)和硫包围的"thio Mo(V)"(g=1.98)共振信号.在钼基催化剂中添加CoO后,"oxo Mo(V)"含量减少,而"thio Mo(V)"含量增加.钴的加入削弱了Mo O Si的相互作用,使Mo6+和"oxo Mo(V)"易被硫化还原为MoS2.

The magnitude sequence of the different carries promoted the activity of the catalyst K 2MoO 4 and that of three kinds of oxides promoted the activity of the catalyst K 2MoO 4/SiO 2 for the syntheses of the methanthiol from syngas are as follows: SiO 2>AC>CNTs>Al 2O 3 and CoO>NiO>Fe 2O 3 respectively. Over the catalyst m (K 2MoO 4)∶ m (CoO)∶ m (SiO 2)=5∶1∶20, the yield of methanthiol is found to reach 0.76 g·h -1 ·g -1 cat , which is 1.5 times higher than that on the catalyst m (K 2MoO 4)∶ m (SiO 2)=5∶20. The apparent activation energies of the two catalysts are counted to be 53.6 kJ·mol -1 and 83.5 kJ·mol -1 respectively. The resonant signals of 'oxo Mo(V)'( g =1.93) and'thio Mo(V)'( g =1.98) is detected by ESR. As the content of CoO increases, the amount of 'oxo Mo(V)'( g =1.93) decreases while that of 'thio Mo(V)'( g =1.98) increases. The addition of CoO weakens the interaction of Mo O Si, making Mo 6+ and 'oxo Mo(Ⅴ)' easy to be sulfurated reduced to MoS 2.