共查询到20条相似文献,搜索用时 93 毫秒
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Dawson结构钼钒磷杂多化合物对苯酚过氧化氢羟化作用的研究 总被引:14,自引:0,他引:14
Dawson结构钼钒磷杂多化合物对苯酚过氧化氢羟化作用的研究于剑锋,杨宇,吴通好,孙家锺(吉林大学化学系理论化学研究所,长春,130023)关键词Dawson结构钼钒磷杂多化合物,苯酚羟化,过氧化氢苯二酚(DBH)是重要的化工原料.由芳香化合物羟化制... 相似文献
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研究了铁(Ⅱ)-L(L=C2O42-、EDTA、CN-、C5H5-、1,10-phenanthroline和2,2′-dipyridine)对苯酚羟化反应的催化作用.结果表明,催化剂的苯酚羟化活性与它们的氧化还原电位有关,电位过高和过低都不利于苯酚羟化反应的进行.本文同时提出了苯酚羟化的反应机理,对实验结果进行了合理的解释 相似文献
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CuZSM—5分子筛上苯酚羟化制苯二酚 总被引:1,自引:0,他引:1
在Na2O-SiO2-CuO-H2O体系中以15%TPABr-85%HMDA为模板剂合成了CuZSM-5分子筛,并用XRD,IR及SEM等方法进行了表征,考察了CuZSM-5分子筛催化苯酚与过氧化氢的羟化活性,研究了催化剂用量,反应温度,反应时间及n(PbOH)/n(H2O2)等对羟化活性的影响。 相似文献
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八羟基喹啉铁(Ⅱ)/MCM-41对苯酚羟化的催化作用 总被引:6,自引:0,他引:6
利用MCM-41中孔分子筛为载体,制备了负载型八羟基喹啉铁(Ⅱ)/MCM-41(简记为Fe(Ⅱ)-Qx/MCM-41)催化剂.XRD,IR证明八羟基喹啉铁(Ⅱ)配合物成功地负载于MCM-41分子筛中.考察了八羟基喹啉铁(Ⅱ)/MCM-41对苯酚羟化反应的催化作用,和未负载的配合物相比,苯酚的转化率、对苯二酚的选择性以及H2O2的利用率都有显著的提高.同时也探讨了温度、反应介质及介质pH值对苯酚羟化反应的影响.结果表明,随着温度的提高,苯酚的转化率增加,但温度太高,易导致副产物增多;有机溶剂不利于羟化反应的进行,水是实验条件下苯酚羟化反应的最佳反应介质;在一定程度上,pH值越低,越有利于反应活性的提高,若pH值太低,活性反而下降,pH值升高不利于苯酚羟化反应的进行.该催化剂也具有较高的稳定性. 相似文献
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苯二酚 ( DHB)是一种重要的化工原料 ,由苯酚过氧化氢羟化制苯二酚的生产路线 ,反应工艺简单 ,不污染环境 ,被认为是 2 1世纪最有价值、最有前途的工艺路线之一 .其关键在于研制高活性、高选择性的催化剂以提高产率使之实现工业化 .迄今为止 ,用于催化苯酚过氧化氢羟化制苯二酚的杂多化合物尚仅限于具有 Dawson结构的钼钒磷、钨钒磷杂多化合物[1,2 ] .本文设计合成了含稀土元素钆的二元杂多化合物 ( NH4 ) 11Gd[Gd4 Mo2 9O10 0 ( H2 O) 16]· 33H2 O,添加适量 V2 O5后应用于苯酚过氧化氢羟化制苯二酚反应 ,取得较好的催化效果 .称取 … 相似文献
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铁—过氧化氢—变色酸催化动力学光度法测定量铁 总被引:10,自引:3,他引:10
本文研究了在H2PO4介质中,痕量铁(Ⅲ)催化过氧化氢氧化变色酸的褪色指示反应及最佳实验条件条件和动力学参数,建立了测定痕量铁的新方法。 相似文献
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ZnFe2O4中阳离子分布对苯酚H2O2羟化制苯二酚催化活性的影响 总被引:2,自引:0,他引:2
具有尖晶石结构的铁酸盐是苯酚H2O2羟化合成苯二酚的有效催化剂.分别用共沉淀和水热法制备了ZnFe2O4,并用Mossbauer,XRD和ESR等方法予以表征.发现不同方法制备的ZnFe2O4中阳离子在四面体和八面体位置的分布不同,认为阳离子分布影响了催化活性. 相似文献
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利用MCM-41中孔分子筛为载体,制备了我载型八羟基喹啉铁/MCM-41催化剂。XRD,IR证明八羟基喹吉林 铁配合物成功地负载于MCM-41分子筛中。考察了八羟基喹啉铁/MCM-41对苯酚羟化反应的催化作用,和未负载的配合物相比,苯酚的转化率,对苯二酚的选择以及H2O2的利用率都有显著的提高。 相似文献
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合成了(NH4)15「Ce(PMo9V2O39)2」.5H2O杂多化合物,并用ICP,IR,UV,XRD等手段对其结构进行表征,结果表明该化合物是具有Keggin结构的杂多化合物。考察了该杂多化合物对苯酚过氧化氢羟化反应的催化活性,研究了反应介质、反应温度、反应时间、反应体系PH及molPhOH:molH2O2对催化活性的影响。实验结果表明:以甲醇为溶剂,用标题化合物作催化剂,当molPhOH:m 相似文献
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V. G. Isakova E. A. Goncharova O. A. Bayukov G. N. Churilov 《Russian Journal of Applied Chemistry》2011,84(7):1165-1169
The possibility was explored for synthesizing polyhydroxylated fullerenes directly from soot containing iron nanoparticles
stabilized by carbon shell. 相似文献
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以偏钒酸铵为钒源,采用溶胶-凝胶法合成了不同钒含量的六方介孔硅(V-HMS)分子筛,利用X射线衍射、N2吸附-脱附和程序升温还原(H2-TPR)对合成的催化剂进行了表征,考察了V-HMS对苯羟基化反应的影响。 结果表明,钒进入了分子筛骨架,并且在HMS分子筛上具有较好的分散性。 V-HMS对苯羟基化反应具有良好的催化活性;高分散的钒氧物种有利于提高苯的羟基化反应性能,溶剂乙腈对反应促进作用明显。 乙腈为溶剂,w(V(5.8)-HMS)=2%,60 ℃反应5 h,苯酚收率达到18.55%,选择性达到100%。 相似文献
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Jun Chen Dong Wei Qun Shi Yu Fen Zhao Yan Mei Li 《中国化学快报》2007,18(5):542-544
Hydroxylation of 3-nitrotyrosine (3-NT) and 3-NT containing peptide Gly-nitroTyr-Gly in aqueous solution by hydroxyl radical were investigated with gamma irradiation. The structures of the hydroxylated products were confirmed by electrospray ionization mass spectrometry and 1H NMR spectrometry. The reactivity of 3-nitrotyrosine has been investigated using density functional theory (DFT) calculation. 相似文献
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金属卟啉催化下环己烷羟基化反应中的Hammett关系 总被引:2,自引:0,他引:2
合成了40个卟啉环上具有不同取代基的单铁、锰卟啉和u-氧桥连双铁、锰卟啉,研究了这些金属卟啉模拟细胞色素P-450单充氧酶在温和条件下催化环己烷羟基化的反应.首次用线性自由能关系对金属卟啉仿生催化反应和金属卟啉自氧化反应进行相关分析,获得一些新的结果和规律.在此基础上,对金属卟啉仿生催化反应的可能机理进行了探讨. 相似文献
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Superoxide radical anion (O2*-), generated by KO2/crown ether, is effective for hydroxylation of nitronaphthalenes. When mono- and di-nitronaphthalenes are treated with KO2/crown ehter, hydroxylation results at the electron-deficient site caused by the electron withdrawing effect of the substituted nitro group. Kinetic experiments suggest that the hydroxylation proceeds by two different mechanisms dependent on the first one-electron reduction potential of nitronaphthalenes. 相似文献
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Jonathan Becker Puneet Gupta Dr. Friedrich Angersbach Prof. Dr. Felix Tuczek Prof. Dr. Christian Näther Prof. Dr. Max C. Holthausen Prof. Dr. Siegfried Schindler 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(33):11735-11744
The formation of a bis(μ‐oxido)dicopper complex with the ligand 2‐(diethylaminoethyl)‐6‐phenylpyridine (PPN) and its subsequent hydroxylation of the pendant phenyl group (studied earlier by Holland et al., Angew. Chem. Int. Ed. 1999 , 38, 1139–1142) has been reinvestigated to gain a better understanding of such systems in view of the development of new synthetic applications. To this end, we prepared a simple copper imine complex system that also affords selective o‐hydroxylation of aromatic aldehydes by using dioxygen as the oxidant: Applying the ligand N′‐benzylidene‐N,N‐diethylethylenediamine (BDED), salicylaldehyde was prepared in good yields and we show that this reaction also occurs through an intermediate bis‐μ‐oxido copper complex. The underlying reaction mechanism for the PPN‐supported complex was studied at the BLYP‐D/TZVP level of density functional theory and the results for representative stationary points along reaction paths of the BDED‐supported complex reveal a closely related mechanistic scenario. The results demonstrate a new facile synthetic way to introduce OH groups into aromatic aldehydes. 相似文献
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Dihydroxybenzene are both very important chemical products. The oxidation of phenol to produce catechol and hydroquinone has been researched extensively since the 1970s. In this paper, the iron complex oxide was prepared by the air oxidation of aqueous suspension method and the catalytic activities were investigated in the hydroxylation of phenol with H2O2 to catechol and hydroquinone. The results showed that the catalyst had higher catalytic activities and the phenol conversion could reach 24% when the phenol/H2O2 (mole ratio) was 3 and the catechol/hydroquinone (mole ratio) 1.5 in products. Furthermore, the interaction of the catalyst with H2O2 had also been demonstrated by IR spectrometry. In the presence of H2O2 a band at 956 cm-1 appeared and disappeared when the H2O2 is replaced by H20 or the catalyst was heated over 373 K, at which temperature decomposition of iron peroxide was very likely. The band at 956 cm-1 was due to the formation of structure of iron peroxide species and the stretching vibration of surface 0-0 species. The results of IR studies suggested that the catalyst might be react with hydrogen peroxide to form iron peroxide, which decomposed to produce·OOH radical. In the presence of DMPO (5,5-dimethyl-1-pyrroline-N-oxide) the·OH radical was also successfully captured in the hydroxylation of phenol by H2O2 over iron complex oxide catalyst in the first time that has been confirmed by means of ESR spectrometry. The results of ESR suggested the process of hydroxylation of phenol with H2O2 was probably a radical process. A possible mechanism of the catalytic process was proposed. 相似文献