选择性氧化结合红外光谱定量分析减压渣油中的硫醚硫

减压渣油中的硫主要是硫醚硫和噻吩硫,但因渣抽结构组成复杂.很难直接定量.若用选择性氧化剂将减压渣油中的硫醚硫选择性氧化成相应亚砜.借助亚砜S= O键在 1030 cm-1附近的强红外振动吸收,就可用红外光谱仪测定亚砜.从而得到相应硫醚硫含量.以KIO3为选择性氧化剂.以已知硫醚硫含量的胜利减压渣油为标样(ωs=0.47% ),选择性氧化后,测定其在 1030 cm-1处的峰面积A(?),依据Lambert- Beer定律.求出渣油亚砜的红外吸收系数K(13.3 L·g-1).然后测定其它油样选择性氧化后在 1030 cm-1处的峰面积,求出亚砜硫浓度后进而求出相应硫醚硫的含量.测定结果与电化学方法所得结果一致.

FTIR-OXIDATION FOR QUANTIFICATION OF SULFIDIC SULFUR IN VACUUM RESIDUE

Sulfur in vacuum residue mainly includes two types of sulfidic sulfur and thiophenic sulfur. It is difficent to directively quantificate vacuum residue due to their complex composition and configuration as well as large molecular weight. Sulfidic sulfur in VR can be selectively oxidized to its related sulfoxides. Then sulfoxidic sulfur can be quantified by means of its IR absorption at 1030cm~(-1) by using IR apparatus, and sulfidic sulfur can be indirectly quantified. KIO3 was used as a selective oxidant, Shengli vacuum residue as a standard specimen. Sulfidic sulfur of the specimen determined by potential titration was 0. 47%. The oxidized sample was subjected to FTIR analysis, CCl4 as a reference. In the same way, other samples were subjected to IR-oxidation, the contents of sulfoxidic sulfur in the oxidized samples then in the original vacuum residue were calculated. The results were very agreeable to those determined by potential titration. FTIR-oxidation is effective for determination of sulfidic sulfur in vacuum residue.