取代水杨醛Schiff碱金属配合物催化氧化脱硫性能

以水杨醛类Schiff碱为配体,与Co(NO_3)_2、Cu(NO_3)_2反应合成6种Salen(M)型配合物Ⅰ～Ⅵ。以1-己硫醇、二丁基硫醚和2-甲基噻吩为模型化合物配制模拟油体系,考察了配合物Ⅰ～Ⅵ的催化氧化脱硫性能,并分析了配合物结构与氧化脱硫性能的关系。结果表明,6种配合物在75 min时的总脱硫效果为Ⅵ>Ⅴ>Ⅳ>Ⅰ>Ⅲ>Ⅱ,Ⅵ的总脱硫率为31.9%。对1-己硫醇及二丁基硫醚脱除效果最佳的是Ⅴ,脱除率分别为74.2%和65.1%;对2-甲基噻吩脱除效果最好的是Ⅰ,脱除率为26.8%。构效关系研究表明,中心金属离子与O_2的配位能力越强,配体的共轭体系越大、电子云密度越高,配合物的脱硫性能越好;通过IR和离子色谱对单一硫化物模拟油体系氧化前后的产物进行分析发现,硫化物氧化后皆生成相应的砜类或亚砜类,且1-己硫醇和二丁基硫醚被进一步氧化生成SO_3~(2–)或SO_4~(2–)。

Catalytic Oxidative Desulfurization Performance of Substituted Salicylaldehyde Schiff Base Metal Complexes

Six Salen(M) complexes, I~VI, were synthesized from salicylaldehyde Schiff base ligands and Co(NO3)2 and Cu(NO3)2. The simulated oil system was prepared by using 1-hexanethiol, dibutyl sulfide and 2-methylthiophene as model compounds to investigate the catalytic oxidative desulfurization performance of complexes I~VI. The effects of central metal ions and ligands on the oxidative desulfurization performance of complexes I~VI were analyzed. The results showed that the order of the total desulfurization effect for the six desulfurizers on the simulated oil in 75 min was VI>V>IV>I>III>II, and the total desulfurization rate of complex VI was 31.9%. Among them, complex V exhibited the best removal effect for 1-hexanethiol and dibutyl sulfide with 74.2% and 65.1% removal rate, respectively. While complex VI had the best removal effect for 2-methylthiophene with a removal rate of 24.4%. According to the structure-property relationship analysis, the stronger the coordination ability between the central metal ion and O2, the larger the conjugated system of the ligand, and the higher density of electron cloud, the better the desulfurization performance of the complex. The products before and after oxidation of the single sulfide simulated oil system were analyzed by infrared spectroscopy (IR) and ion chromatography (IC). It was found that three sulfides were oxidized to form corresponding sulfones or sulfoxides, and 1-hexanethiol and dibutyl sulfide were further oxidized to form SO32- or SO42-.