【作者】 周维友；

【导师】 刘祖亮； 胡炳成；

【作者基本信息】 南京理工大学 ， 化学工程与技术， 2010， 博士

【摘要】 烃类选择性催化氧化反应是石油化工中的重要反应之一,寻找C-H键有效的活化方法,调控反应进程和氧化深度,并提高目标产物的选择性,是当前化学工业发展中迫切需要解决的问题,其研究成果具有非常重要的意义。卟啉类仿生催化剂是国内外研究最多,发展潜力最大的一种烃类氧化反应催化剂,但是其合成成本很高,尤其是多取代卟啉类化合物；另一方面,卟啉类仿生催化剂的催化活性和选择性仍需进一步提高。次卟啉衍生物是以来源充足的血红素为原料合成的一类卟啉类物质,其结构更接近于天然单加氧酶P-450的辅基。因此,以次卟啉衍生物为基础,研究其仿生催化性能,必将为仿生催化剂结构的设计及寻找高性能的氧化反应催化剂提供了新的思路。本论文以氯化血红素为原料,首先合成了次卟啉二甲酯（10）,并在其环周的3-／8-位进行改性修饰,合成了一系列次卟啉衍生物17-21,在13-／17-位进行改性修饰合成了化合物11～16及22～24；其次是设计合成了具有两个活性中心的含有二硫键结构的金属次卟啉衍生物26和28；最后将次卟啉负载到聚乙二醇载体上,制备了负载型次卟啉仿生催化剂29。将合成的这些次卟啉衍生物配体与金属离子络合后,详细考察了它们在催化烃类空气氧化反应中的催化活性、选择性及负载型催化剂的重复使用性能。将次卟啉二甲酯的金属络合物用于催化空气氧化环己烷、对二甲苯及环己烯的反应,结果表明,金属次卟啉二甲酯在反应条件下能够较好的催化烃类的氧化反应,以环己烷的氧化为例,反应3.5 h后,其最高转化率达到18.6%,选择性为84.6%,催化剂的转化数为85147,明显高于简单的金属四苯基卟啉类催化剂。经过对催化反应机理探讨后发现,这可能与它们在反应过程中形成活性中间体高价金属氧络合物的途径有关。将3-／8-位被吸电子基团取代的金属次卟啉二甲酯衍生物用于催化空气氧化环己烷的反应,结果表明,吸电子基团取代的金属次卟啉二甲酯的催化活性比未取代的有所提高。其中Co（Ⅱ）[DP（β-Br）₂DME]的催化活性最好,反应3.5 h,环己烷的转化率达到23.57%,环己酮和环己醇的总产率已超过20%,这主要是因为吸电子取代基增加了金属次卟啉衍生物的氧化还原电位,从而提高了其催化活性。将13-／17-位改性的金属次卟啉二甲酯衍生物用于催化空气氧化环己烷的反应,结果表明,取代基团的体积及电子性能影响着金属次卟啉衍生物的催化活性,取代基团的体积越大,催化活性越低,当以Co（Ⅱ） （DPDOE）为催化剂时,反应4.0 h后,环己烷的转化率降到了15.0%,转化数比钴次卟啉二甲酯催化结果降低较多。这主要是因为体积较大的基团阻碍了μ-氧-双金属络合物中间体的生成。研究了含有二硫键的金属次卟啉衍生物在环己烷空气氧化反应中的催化活性及作用特点。以Co（Ⅱ） （TPMP）为例,环己烷的最高的转化率达到27.4%,环己醇与环己酮的总的选择性达到92.0%。催化活性比简单的金属次卟啉二甲酯有了大幅度的提高。这主要是因为分子结构中的二硫键起了助催化剂的作用,首先,作为轴向配体的硫可以有效地促进高价金属氧络合物活性中间体的生成；其次,二硫键的氧化还原性质促进了环己基过氧化氢的分解,从而增强了其催化活性。最后研究了聚乙二醇负载型金属次卟啉催化剂在环己烷的空气氧化反应中的催化活性及重复使用性能。结果表明,负载后的金属次卟啉催化剂催化环己烷氧化产率达到最大值的时间比未负载的催化剂延长了1.0～1.5 h。尽管催化活性降低了,但是,环己醇和环己酮的总的选择性有了一定程度的提高,催化剂的重复使用性能也得到了增强。更多还原

【Abstract】 The selective oxidation of hydrocarbon is one of the most important reactions in the chemical engneering. Finding the catalysts for the activation of C-H bond is the pivotal issue in the development of chemistry. Metalloporphyrins, as one kind of biomimetic catalysts for cytochrome P-450, are the potential catalysts for the oxidation of hydrocarbon and have been attracting much attention from organic and industrial chemists. However, several drawbacks exist. On the one hand, preparations of these porphyrins, especially the substituted ligands are very expensive; on the other hand, the catalytic activity and selectivity of these catalytic reactions still need to be improved. Deuteroporphyrin dimethylester and its metallo complexes can be prepared in high yield from the red blood pigment heme which is available in almost any desired amount from slaughterhouse wastes. The high accessibility of deuteroporphyrin dimethylester together with its excellent stability and the close relationship to the naturally hemes makes it an ideal compound to mimic enzymatic systems based on heme. Investigation of the biomimetic catalytic activities of the metallodeuteroporphyrin derivatives should be helpful to developing and designing the new and effective catalysts for oxidation.In this thesis, firstly, we synthesized the compound deuteroporphyrin dimethyl ester from chloro hemin, then the compounds 17～21 were prepared by introducing different substituents into the 3-/8-sites of deuteroporphyrin and the compounds 11～16 and 22～24 were synthesized by introducing different substituents into the 13-/17- sites of deuteroporphyrin. Secondly, we synthesized the compound 26 and 28, which contain dithiol bond and two active centres. Thirdly, we have supported deuteroporphyrin on the PEG1500 by covalent bond. Then, these synthesized ligands were complexed with metallo ions and their catalytic activities and selectivities in the oxidation of hydrocarbon with air were studied in detail.The metallodeuteroporphyrins [metal=ClFe(Ⅲ), Co(Ⅱ) and ClMn(Ⅲ)], have been used as the catalysts in the oxidation of cyclohexane,p-xylene and cyclohexene with air as the oxidant. According to the results of our experiments, metallodeuteroporphyrins can smoothly catalyze the oxidation of these substrates under the selected conditions. For example, in the oxidation of cyclohexane catalyzed by Co(Ⅱ) (DPDME), the conversion and the total selectivity of cyclohexanol and cyclohenone have reached 18.6% and 84.6%, respectively. The turnover number of the catalysts is 85147, markedly higher than that of the simple metallo-porphyrins. These results may be attributed to their different mechanism in forming the active medium.The metallodeuteroporphyrins derivatives with different substituents in 3-/8-sites have been used as the catalysts in the oxidation of cyclohexane with air. The results indicate that withdrawing-electron substituents can improve the catalytic activities of metallodeuteroporphyrins. Co(Ⅱ) [DP(β-Br)2DME] shows the highest activity. The conversion of cyclohexane has reached 23.57% and the total yield of cyclohexanol and cyclohexnone is more than 20%. The reason is that the withdrawing-electron substituents can increase the redox potential of the complex and improve the catalytic activities of these metallodeuteroporphrin derivatives.The metallodeuteroporphyrin derivatives with different substituents in 13-/17-sites have been used as the catalysts in the oxidation of cyclohexane with air. The results indicated that both the size and electronic properties of substituents influence the catalytic activity of metallodeuteroporphyrin derivatives. The activity decreased with the increasing of the size of goups. When Co(Ⅱ) (DPDOE) was used as the catalysts, the conversion of cyclohexane decreased to 15.0% with the reaction time 4.5 h, and the turnover number was also markedly lower than that of Co(Ⅱ) (DPDME). These results may be attributed to the fact that the big substituents hamper the formation of the mediumμ-oxo metallocomplexes.The catalytic activities of the metallodeuteroporphyrins containing dithiol bond have also been studied in the oxidation of cyclohexane with air. The results show that the catalytic activity has been evidently improved. Taking the Co(Ⅱ) (TPMP) as the example, the conversion of cyclohexane and the total selectivity of cyclohexanol and cyclohexnone have reached 27.4% and 92.0%, respectively. The phenomenone should be attributed to the dithiol bond in the molecular structure. On the one hand, the thiol can complexe to central metallo ion and facilated the formation of active medium; on the other hand, the redox property of dithiol can help the dehydrogenation of cyclohexanylperoxide and increase the yield of products.Finally, the catalytic activity of PEG1500-supported deuteroporphyrin has been studied in the oxidation of cyclohexane with air. The results shows that the time when the yield reached the highst is prolonged by 1.0～1.5h. Although the catalytic activity decreases, the total selectivity of cyclohexanol and cyclohexanone increases in a certain extent and the catalysts can be recycled twice.更多还原