Efficient oxidation of ethylbenzene catalyzed by cobalt zeolitic imidazolate framework ZIF-67 and NHPI

Efficient catalytic oxidation of ethylbenzene to acetophenone was realized using the catalytic system of cobalt zeolitic imidazolate framework ZIF-67/N-hydroxyphthalimide （NHPI） under mild conditions. 95.2% conversion of ethylbenzene with 90.3% selectivity to acetophenone could be obtained at 373 K under 0.3 MPa 02 for 9 h. The results show that there exists synergetic effect between ZIF-67 and NHPI. 1-Phenylethyl hydroperoxide （PEHP） was generated via a radical process involving the hydrogen abstraction from ethylbenzene by phthalimide N-oxyl, and subsequently effectively decomposed to acetophenone by ZIF-67.     

N-羟基邻苯二甲酰亚胺和二氧化锰高效催化对硝基甲苯氧化

采用N-羟基邻苯二甲酰亚胺(NHPI)和二氧化锰(MnO2)作为催化剂催化对硝基甲苯的氧化反应以制备对硝基苯甲酸;对反应条件进行了优化.结果表明,采用10%(与原料的摩尔比)NHPI和10%(与原料的摩尔比)MnO2作为催化剂,在110℃、氧气压力0.4 MPa下反应4 h,对硝基甲苯的转化率为97%,对硝基苯甲酸的分...     

甲苯氧化制苯甲酸的新催化体系

以分子氧为氧化剂,探索了甲苯氧化制苯甲酸的新催化体系,第一次把N-羟基邻苯二甲酰亚胺(NHPI)与钴盐组成的催化剂用于甲苯氧化反应.实验揭示:以NHPI/Co(acac)2(乙酰丙酮酸钴)和NHPI/Co(OAc)2(醋酸钴)为催化剂时,苯甲酸的收率可分别为55.5%与41.2%,文中还对氧气压力、反应温度与时间等对反应的影响进行了讨论,同时提出了可能的反应机理.     

聚合物微球固载N-羟基邻苯二甲酰亚胺催化剂的制备及其催化氧化性能初探

首先采用悬浮聚合法,制备了甲基丙烯酸缩水甘油酯(GMA)和甲基丙烯酸甲酯(MMA)的交联聚合物微球(GMA/MMA),然后经过几步大分子反应在微球表面合成与固载了N-羟基邻苯二甲酰亚胺(NHPI),形成固载有NHPI的功能微球GMA/MMA-NHPI。采用红外光谱(FT-IR)及扫描电子显微镜(SEM)等方法对功能微球进行了表征。结果表明,以含环氧基团的GMA/MMA为载体,通过大分子反应可实现NHPI的合成与固载。GMA/MMA-NHPI与醋酸钴(Co(OAc)2)构成的共催化体系,在分子氧对环己烷和环己醇的氧化过程中,显示出良好的催化活性。     

Unusual Effects of Pure Nonionic and Mixed Nonionic–Cationic Micelles on the Rate of Alkaline Hydrolysis of N-Hydroxyphthalimide

Pseudo-first-order rate constants, k_obs, for the alkaline hydrolysis of N-hydroxyphthalimide, 1, at 0.02 M NaOH and 30°C remain essentially independent of the total concentration of C₁₂E₂₃, [C₁₂E₂₃]_T, at ≤0.005 M C₁₂E₂₃. The increase in [C₁₂ E₂₃]_T from 0.005 to 0.015 M causes a nonlinear decrease in k_obs. The rate of hydrolysis becomes either too slow or the change in absorbance values becomes significantly small to allow a reliable observed data fit to a first-order kinetic equation at ≥0.020 M C₁₂E₂₃ in the absence and presence of total concentration of cetyltrimethylammonium bromide, [CTABr]_T ranging from 0.003 to 0.020 M. The values of fraction of nonionized 1, F_SH, obtained at reaction time t = 0 and 0.02 M NaOH, remain ～0 at ≤0.010 M C₁₂E₂₃ while they increase from 0.39 to 0.89 with the increase of [C₁₂E₂₃]_T from 0.015 to 0.10 M. The values of k_obs show a nonlinear decrease of ～5-fold with the increase of [C₁₂E₂₃]_T from 0.0 to 0.010 M in the presence of 0.02 M NaOH and [CTABr]_T range of 0.003 to 0.020 M. The values of F_SH remain ≤～0.10 at ≤0.015 M C₁₂E₂₃ while they vary between 0.40 and 0.90 within a [C₁₂E₂₃]_T range 0.02 to 0.05 M in the presence of 0.02 M NaOH and [CTABr]_T ranging from 0.003 to 0.020 M. The values of F_SH represent the fraction of nonionized 1 trapped almost irreversibly by pure C₁₂E₂₃, and mixed C₁₂E₂₃–CTABr micelles.     

An Upstream By‐product from Ester Activation via NHC‐Catalysis Catalyzes Downstream Sulfonyl Migration Reaction

A sequential reaction combining N‐heterocyclic carbene (NHC) and N‐hydroxyphthalimide (NHPI) catalysis allowed for the upstream by‐product NHPI, which was generated in the NHC‐catalyzed cycloaddition reaction, to act as the catalyst for a downstream nitrogen‐to‐carbon sulfonyl migration reaction. Enantiomeric excess of the major product in the cycloaddition reaction remained intact in the follow‐up sulfonyl migration reaction.     

聚合物微球固载的N-羟基邻苯二甲酰亚胺在分子氧氧化甲苯过程中的催化性能

以交联聚苯乙烯(CPS)微球为基质,经过几步大分子反应在微球表面合成与固载了N-羟基邻苯二甲酰亚胺(NHPI),形成固载有NHPI的聚合物微球CPS-NHPI。本文主要将CPS-NHPI与过渡金属盐组成共催化体系,用于分子氧氧化甲苯的反应,考察了该非均相催化剂的催化特性与催化氧化机理。结果表明,几种过渡金属盐中,Co(OAc)2的助催化效果最好;微球CPS-NHPI与Co(OAc)2所构成的共催化体系,在温和条件(80℃和常压氧气)下可有效地将甲苯深度氧化为苯甲酸,显现出高的催化活性(甲苯转化率达到57%)与优良的选择性(苯甲酸的选择性达到84%)。催化氧化反应遵循自由基链式反应机理。主催化剂CPS-NHPI固载的NHPI与助催化剂Co(OAc)2适宜的摩尔比为14∶1,主催化剂所含NHPI为底物的12(mol)%时,催化剂用量较为合适。固体催化剂CPS-NHPI具有良好的再循环使用性能。     

非过渡金属催化体系NHPI/DDQ/NaNO2催化分子氧选择氧化醇

考察了N-羟基邻苯二甲酰亚胺(NHPI),2,3-二氯-5,6-二氰基-1,4-苯醌(DDQ)与NaNO2组成的非金属催化体系,催化分子氧选择氧化醇的反应性能.结果表明,该体系可有效地催化芳香醇等生成相应的醛(酮).在80℃反应6h,苯甲醇转化率达到65%,苯甲醛选择性为99%.此外,该催化体系也能有效地催化其它醇的选...     

Mechanisms of the C-H halogenation of adamantane in the presence of N-hydroxyphthalimide

A study was carried out on the mechanisms for the halogenation of the C-H bonds in systems containing N-hydroxyphthalimide, oxone, and CHal₄ or N-hydroxyphthalimide and t-BuOCl. These reactions proceed with the participation of the phthalimido-N-oxyl (PINO) radical, which may serve either as an initiator or reagent. A DFT (density functional theory) model showed that the PINO radical may be generated efficiently in the presence of t-BuOCl as the initiator. __________ Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 44, No. 1, pp. 46–51, January–February, 2008.     

Sites of Protonation and Unimolecular Fragmenta tion of Protonated N-Hydroxyphthalimide in the Gas Phase

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