Ti-MWW分子筛催化叔丁基过氧化氢氧化脱硫

Oxidative desulfurization of diesel oil over Ti-MWW catalyst with TBHP as oxidant

以Ti-MWW为催化剂,考察了不同氧化剂对分别含有苯并噻吩、二苯并噻吩和4,6-二甲基二苯并噻吩等有机硫化物模拟油品氧化反应的影响,结果表明,叔丁基过氧化氢对有机含硫化合物的氧化活性明显高于过氧化氢水溶液。以叔丁基过氧化氢为氧化剂,三种噻吩类含硫化合物氧化的难易顺序为二苯并噻吩>4,6-二甲基二苯并噻吩>苯并噻吩,其氧化活性顺序与含硫化合物中硫原子的电子云密度和空间位阻有关。考察了Ti-MWW/叔丁基过氧化氢催化氧化体系对成品柴油的催化氧化脱硫,结果表明,成品柴油中的含硫化合物可被有效地氧化脱除,在优化的反应条件下,经过两次氧化、萃取后,成品柴油中的总硫含量从1 015μg/mL降低至11μg/mL,总脱硫率达到99%。

Oxidative desulfurization（ODS） of benzothiophene（BT）,dibenzothiophene（DBT） and 4,6-dimethyl dibenzothiophene（DMDBT） in model light oil was investigated with different oxidants over Ti-MWW catalyst.The results indicated that tert-butyl hydroperoxide（TBHP） exhibits higher reactivity with these organic sulfur-containing compounds than hydogen peroxide.In the presence of TBHP,the reactivity of these sulfur-containing compounds over Ti-MWW catalyst is in the order of DBT DMDBT BT,which is determined by the electron density of sulfur atom in thiophene ring as well as the steric hindrance of sulfur compounds.ODS of a commercial diesel oil was also investigated over the Ti-MWW/TBHP system.The sulfur compounds in the commercial diesel oil can be efficiently oxidized to corresponding sulfone under mild reaction conditions;by oxidation and extraction twice,the sulfur content in the commercial diesel oil is decreased from 1 015 μg/mL to 11 μg/ mL and the sulfur removal reaches 99%.