载体酸性对镍金属催化剂芳烃加氢抗硫性能的影响

Effects of acidity of the carrier on tolerance to sulfur of nickel-based catalysts for aromatic hydrogenation

制备了不同酸性载体-γAl2O3、HY、SiO2-Al2O3和Sep(海泡石)负载的镍催化剂,在压力1.0 MPa、温度200℃和空速2.0 h-1条件下,用固定床连续流动微反装置对催化剂进行了抗硫性能评价。模型反应物为甲苯-噻吩的混合液,含750μg.g-1噻吩硫,用吡啶吸附红外光谱法研究了催化剂的酸性;用CO原位吸附红外光谱法研究了活性金属Ni的电子性能。结果表明,随载体酸性的增强,Ni原子缺电子性增强,催化剂芳烃加氢活性增加,抗硫性能提高。催化剂的抗硫性能主要与载体表面的B酸有关,与L酸无关。

Several nickel-based aromatics hydrogenation catalysts supported on γ-Al2O3、HY、SiO2-Al2O3and sepiolite were prepared. Tolerance of the catalysts to sulfur poisoning was investigated via hydrogenation of toluene containing thiophene in a fixed-bed continuous-flow microreactor at 1.0 MPa,200 ℃ and LHSV 2.0 h^-1. Acidity of the catalysts were characterized by pyridine-a＆orption and electronic properties by CO-adsorption infrared （IR） spectra. It was shown that electron-deficiency of the Ni species increased with acidity of the carrier and hence enhanced the activity and tolerance to sulfur poisoming. Tolerance of the catalysts to sulfur was mainly dependent on Broensted acid sites on surface of the carrier and was independent on Lewis acid sites.