【作者】 周新锐；

【导师】 杨锦宗； 张淑芬；

【作者基本信息】 大连理工大学 ， 化学工程， 2008， 博士

【摘要】 苯并噻吩（包括一苯并噻吩及二苯并噻吩）类化合物是石油产品中最稳定的一类硫化合物,有效氧化这部分硫化物是达到煤油和柴油深度氧化脱硫的基础。本文采用烷基过氧化物和分子氧为氧化剂,在无水条件下,对模拟燃油和工业柴油中的苯并噻吩类硫化物进行催化氧化反应的研究。首先,以二苯并噻吩（DBT）为靶向物质,DBT的十氢化萘溶液为模拟燃油,过氧化环己酮（CYHPO）为氧化剂,在不同反应条件下,进行催化剂筛选和反应条件优化。采用不同无机和金属有机催化剂,根据氧化反应实验结果,筛选出适合的催化剂为钼氧化物（MoO₃）。为了进一步提高催化剂的活性,进行了载体和其它杂元素对催化活性影响的探讨,结果发现三种载体（弱酸性阳离子交换树脂D113、D751和Al₂O₃）都能提高MoO₃的活性,其中性能最好的是D113;Co和Ni元素的加入明显降低MoO₃/Al₂O₃的催化活性。对催化剂十次重复使用使用效果评定,及等离子体发射光谱检测和定量分析显示:MoO₃/D113和MoO₃/D751十次重复使用效果理想;滤失小于MoO₃/Al₂O₃;。选择其它烷基过氧化物:过氧化叔丁醇（TBHP）和过氧化叔戊醇（TAHP）为氧化剂,在相同条件下进行DBT的氧化反应,结果发现烷基过氧化物的氧化活性顺序为:CYHPO＞TAHP＞TBHP,与它们的过氧键电子密度大小成相反趋势。研究进一步扩大靶向物质范围,在模拟燃油中引进4,6-二甲基二苯并噻吩（DMDBT）和一苯并噻吩（BT）两个具有代表性的模型硫化物,以转化率为活性评定参数,确定它们反应活性顺序为:DMDBT＞DBT＞BT。选择性研究发现,在模拟燃油中加入4,6,8-三甲基-2-壬烯、1-十四烯和2-甲基萘对DBT的转化率没有产生明显影响。咔唑对不同氧化剂产生不同影响,实验表明在咔唑存在下TBHP对DBT的氧化效率显著下降;TAHP受到微小影响;而CYHPO对DBT的氧化反应不受影响,氧化剂的空间位阻可能在选择性上起决定性作用。动力学研究发现,该氧化反应对模型硫化物的反应级次均为一级;推论了CYHPO在MoO₃存在下对DBT氧化的协同机理。其次,进行了分子氧对DBT非均相催化氧化反应的研究。为激发分子氧的氧化活性,采用具有仿生效能的取代酞菁铁为催化剂。合成系列取代酞菁铁:四硝基酞菁铁（FePc（NO₂）₄）、氨基-三硝基酞菁铁（FePc（NO₂）₃NH₂）和四氨基酞菁铁（FePc（NH₂）₄）。探讨了取代基电子效应对酞菁铁催化活性的影响。结果表明:催化剂的活性顺序为:FePc（NO₂）₄＞FePc（NO₂）₃NH₂＞FePc（NH₂）₄,与酞菁环上的电子密度成反比,吸电子基有利于提高催化活性。FePc（NO₂）₄不仅具有最佳催化活性且具有最好的化学稳定性。IR光谱进一步证实FePc（NH₂）₄在第一次氧化反应后,Pc环的典型特征峰(1405 cm^-1和1605 cm^-1)消失;而FePc（NO₂）₄在重复使用5次后,结构保持不变。在反应温度100℃,反应压力0.3 MPa,FePc（NO₂）₄用量1%的条件下,反应时间为2 h时,DBT的转化率达到98.7%。LC-MS认证了氧化产品中有DBT的亚砜存在。最后,以CYHPO为油溶性氧化剂,在包括氧化反应器和Al₂O₃吸附过滤器的实验室单管连续反应装置上,对实际工业柴油进行了连续催化氧化脱硫。柴油脱硫率达到94%以上,回收率大于99%;200μg/g硫含量的柴油,处理后硫含量达到5.1μg/g,符合目前国际超低硫柴油标准（＜10μg/g）;400μg/g和600μg/g硫含量的柴油,处理后硫含量达到14.8μg/g和36.0μg/g,符合我国目前一些城市（北京、上海等）率先使用的低硫柴油标准（＜50μg/g）。更多还原

【Abstract】 The effective oxidation of benzothiophenes and dibenzothiophenes,which are the most stable sulfur-containing compounds in the distillates of petroleum,is the base for developing a deep oxidative desulfurization（ODS） of fuels.This thesis presents the study on the catalytic oxidations of benzothiophene and dibenzothiophenes using alkyl peroxides and molecular oxygen as oxidants in the simulated and industrial diesel fuels under water-free conditions.The catalytic oxidation of dibenzothiophene（DBT） in decahydronaphthalene（decalin） as stimulated fuel was first performed using oil-soluble oxidant,cyclohexanone peroxide （CYHPO）,under various conditions to screen adapted catalyst and optimize reaction conditions.The catalyst with high activity for this oxidation is molybdenum oxide（MoO₃）, and its catalytic activity may increased remarkably by attaching on the macroporous polyacrylic cationic exchange resin D113,weak acidic chelating resin D751 and Al₂O₃,where D113 display the highest performance among the three supporters.The addition of Co and Ni onto the MoO₃/Al₂O₃ led to a significant decrease of its catalytic activity in the oxidation of DBT.Analyses with weight calculation and Inductively Coupled Plasma Spectrum demonstrated that the losses of MoO₃/D113 and MoO₃/D751 were less than MoO₃/Al₂O₃ during 10 consecutive batch reactions,where the catalyst was recycled and reused,meanwhile the catalyst activity was not decreased.When oxidations of DBT using TBHP and TAHP were performed in the same way as using CYHPO,activity of alkyl oil-soluble peroxides showed the decreases in the order:CYHPO＞TAHP＞TBHP.The oxidations of model sulfur-containing compounds,4,6-dimethyl dibenzothiophene（DMDBT） and benzothiophene （BT）,were also carried out.The results indicated that the oxidation activities of these sulfur compounds decreased in the order of DMDBT＞DBT＞BT.The effect of the model unsaturated compounds and nitrogen-containing compounds found in the middle distillates on the oxidation of DBT were also investigated.The results demonstrated that the DBT oxidation was not influenced by 1-tetradecylene,4,6,8-trimethyl-2-nonylene,and 2-methylnaphthalene; whereas influenced differently by carbazole depending on the different oxidants,i.e. conversion of DBT in the oxidation using TBHP was decreased greatly with adding of carbazole,using TAHP was decreased slightly,but using CYHPO was not changed.The reaction kinetics of model sulfur compounds was further investigated.The results suggested that the oxidative reaction of each sulfur compound could be treated as a first-order reaction. Finally,the coordinate mechanism of oxidation of DBT using CYHPO in the presence of MoO₃ was presumed.Next,Oxidation of dibenzothiophene（DBT） using molecular oxygen was performed in an unpolar hydrocarbon solvent under water-free condition.To stimulate the activity of molecular oxygen,iron phthalocyanines（FePc） substituted were employed as catalyst.Three kinds of catalysts with different substituents,FePc（NO₂）₄,FePc（NO₂）₃NH₂ and FePc（NH₂）₄, were synthesized to investigate the effect of substituent on activity and stability of iron phthalocyanines.The results indicated that the catalytic activity of these phthalocyanines decreased in the order of FePc（NO₂）₄＞FePc（NO₂）₃NH₂＞FePc（NH₂）₄,reversing the order of electronic density of Pc resonance ring.FePc（NO₂）₄ not only has the highest activity but also best stability.The decreased activity of FePc（NH₂）₄ may decomposed during the first run of oxidation according to the typical Pc peaks(1405 cm^-1 and 1605 cm^-1) of IR;whereas the catalytic activity and structure of FePc（NO₂）₄ was kept during 5 runs of oxidations.At a temperature of 100℃and an initial pressure of 0.3 MPa,conversion of DBT in decalin reached to 98.7%in presence of 1%of FePc（NO₂）₄ as catalyst.The sulfoxide was detected by LC-MS in this oxidation using molecular oxygen in the presence of FePc（NO₂）₄.Finally,The oxidative desulfurization of industrial diesel fuels was examined in a fixed bed stainless single steel flow reactor and an adsorption column.More than 94%of sulfur of fuels was removed with more than 99%recovery of fuels.The sulfur content of oxidized diesel fuel with an initial sulfur content of 200μg/g was reduced to 5.1μ/g,which is under the ultra sulfur content restriction（＜10μg/g）;with an initial sulfur content of 400μg/g and 600μg/g were reduced respectively to 14.8μg/g and 36.0μg/g,which are under the level of sulfur content of diesel fuel for some special cities such as Beijing and Shanghai etc taking the lead in performing low sulfur regulation of diesel fuels（＜50μg/g）.更多还原