树枝状聚酰胺负载TEMPO的合成及其催化分子氧氧化醇的性能

发布时间：2018-04-28 14:50

  本文选题：树枝状聚酰胺胺(PAMAM) + 2　； 参考：《河北工业大学》2015年硕士论文

【摘要】：醇选择性的氧化成醛酮是化工领域最重要的反应之一。2,2,6,6-四甲基哌啶氮氧自由基(TEMPO)作为一种对光热稳定的催化剂,具有反应条件温和、选择性好、转化率高等优点,但是存在其价格昂贵,沸点与醛酮等产物接近,产物提纯难度大等缺点。因此,研究负载型TEMPO用以催化醇的选择性氧化,实现TEMPO的循环使用具有重要的理论和实际意义。本文以乙二胺和丙烯酸甲酯为原料经重复Michael和酯氨解反应制备出二代(2.0G)树枝状聚酰胺胺(PAMAM)。以PAMAM为载体,经缩合、还原将其与2,2,6,6-四甲基哌啶酮氮氧自由(TEMPO)键连,得到PAMAM负载的TEMPO(PAMAM-TEMPO)。采用~1H NMR、~(13)C NMR以及FT-IR等手段对中间体及最终产物进行了表征。将PAMAM-TEMPO与CuBr_2以及2,2’-联吡啶结合构成催化体系,用于催化分子氧为氧化剂的醇的选择性氧化反应。对该体系的催化性能进行了考察,得到PAMAM-TEMPO/CuBr_2/2,2’-联吡啶催化苯甲醇选择性氧化反应的最优条件,即:苯甲醇2 mmol,PAMAM-TEMPO 1 mol%,2,2’-联吡啶1 mol%,CuBr_2 3 mol%,K2CO_32.5 mol%,乙腈1.25 ml,水1.25ml,反应温度25℃。在此条件下该体系对苄基以及烯丙基伯醇的氧化显示出良好的催化活性和选择性。TEMPO的负载使得氧化产物醛很容易与催化体系分离,而且催化剂可以循环使用。
[Abstract]:The selective oxidation of alcohols to aldehydes and ketones is one of the most important reactions in chemical industry. However, its price is expensive, boiling point is close to aldehydes and ketones, and it is difficult to purify the products. Therefore, it is of great theoretical and practical significance to study the selective oxidation of alcohols catalyzed by supported TEMPO and to realize the recycling of TEMPO. In this paper, the second generation (2.0 G) dendritic polyamide amine (Pama) was prepared from ethylenediamine and methyl acrylate by repeated Michael and ester ammonolysis. Using PAMAM as the carrier, it was reduced by condensation to connect it with the free tetramethylpiperidinone nitrogen oxygen (TEMPO) bond to obtain the PAMAM loaded TEMPOG PAMAM-TEMPO. The intermediate and its final product were characterized by 1H NMR-13C NMR and FT-IR. The selective oxidation of alcohols with molecular oxygen as oxidant was catalyzed by the combination of PAMAM-TEMPO with CuBr_2 and 2H _ 2O _ 2-bipyridine. The catalytic properties of the system were investigated. The optimum conditions for the selective oxidation of benzyl alcohol catalyzed by PAMAM-TEMPO / CuSP / CuBr2 / 2 / 2 + -bipyridine were obtained, namely: benzyl alcohol 2 mmol-TEMPO 1 mol-dipyridine-2-mol-dipyridine-3-molK2CO32.5 mol-1, acetonitrile 1.25 ml, water 1.25 ml, reaction temperature 25 鈩，

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