Aerobic Oxidation Catalyzed by Mixed Addenda Heteropolyoxometarates

研究了各种钒、钼的氧化反应。此外，在对苯二酚存在下，Pd(II)与钒钼磷(NPVMo)的结合是分子氧氧化烯烃的有效催化体系。在本项目中，我们取得了以下成果。在相对温和的条件下，(NH_4)_5H_6PV_4Mo_8O_(40)催化芳香胺、苯甲醇和苯酚与分子氧反应生成相应的亚胺、苯甲醛和苯二酚。以分子氧为终氧化剂的间接氧化法的研究进展在NPVMo催化剂上，对苯二酚与分子氧顺利脱氢生成对苯二酚。通过Pd(II)与该体系的结合，开发了一种新的氧化体系。因此，多种环烯烃如环己烯在醋酸中被Pd(II)/对苯二酚/NPVMo/O2体系进行酰化反应，生成3-乙酰氧基-1-环烯烃。在该催化体系下，丙烯酸乙酯和丙烯腈在乙醇中发生缩合反应，以较高的产率生成相应的缩醛。以N-羟基邻苯二甲酰亚胺(NHPI)为催化剂进行氧化反应，发现N-羟基邻苯二甲酰亚胺(NHPI)能较好地催化以分子氧为氧化剂的苄基化合物生成醇或酮。该催化氧化是一种新型的好氧氧化体系。在Co(Acac)n(n=2或3)存在下，NHPI实现了环己烷等烷烃的氧化。例如，环己烷以合理的产率转化为环己酮和己二酸。该方法已扩展到各种有机基质的好氧氧化。

Oxidations of variountaining vanadium and molybdenum were examined. In addition, the combination of Pd (II) with vanadomolybdophosphate (NPVMo) in the presence of hydroquinone was found to be an efficient catalytic system for the oxidation of alkenes with molecular oxygen. We have obtained the following results in this project.1. Oxidation of various organic substrates with molecular oxygen by NPVMoVanadomolybdophosphate (NPVMo), which can be shown as (NH_4) _5H_6PV_4Mo_8O_<40>, catalyzed the oxidation of aromatic amines, benzyl alcohols and phenols to the corresponding imines, bezaldehydes and quinoes with molecular oxygen under relatively mild conditions.2. Development of indirect oxidation using molecular oxygen as final oxidantHydroquinone was smoothly dehydrogenated with molecular oxygen to quinone by NPVMo. By combination of Pd (II) and this system, anew oxidation system has been developed. Thus, a variety of cycloalkenes such as cyclohexene underwent the acylation in acetic acid by Pd (II) /hydroquinone/NPVMo/O_2 system to form 3-acetoxy-1-cycloalkenes in quantitative yields. When ethyl acrylate and acrylonitrile was allowed to react in ehtanol by the use of this catalytic system, acetalization took place to form the corresponding acetals in good yields.3. Oxidation by the use of N-hydroxyphthalimide as catalystN-Hydroxyphthalimide (NHPI) was found to catalyze the oxidation of benzylic compounds with molecular oxygen to give alcohols or ketones in fair yields. This catalytic oxidation was found to be a novel aerobic oxidation system. The oxidation of alkanes such as cyclohexane was achieved by NHPI in the presence of Co (acac) n (n=2 or 3). For example, cyclohexane was converted to cyclohexanone and adipic acid in fair yields. This method was extended to the aerobic oxidation of various organic substrates.