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511.
A series of modified polyethylenimines (PEIs) containing oxime groups and cetyl groups were prepared. The dissociated constants of oxime group and the rate constants of its reaction with p-nitrophenyl diphenyl phosphate (PNPDPP) were determined. These polymers are good catalysts for the cleavage of PNPDPP under aqueous conditions. Rate accelerations approach 10~4-10~5-fold level with turnover behavior. Reaction mechanism is analogous to that of enzyme-catalyzed kinetics. 相似文献
512.
采用FT-IR、 NH_3-TPD和~(27)Al MAS NMR等催化剂表征手段和间歇反应方法,系统研究了NaOH溶液(0.2~0.4mol/L)的碱改性和NaOH溶液与硝酸溶液(0.2 mol/L)的碱-酸组合改性对一种氢型Y沸石(Si/Al=7.5)的物化性质和环己酮肟液相贝克曼重排反应性能的影响.结果表明,碱改性具有脱硅作用,可使Y沸石的表面Bro¨nsted酸中心和Lewis酸中心数量显著增加.酸处理具有脱铝作用,可以选择性地脱除Y沸石中的一部分非骨架铝,从而降低碱改性催化剂的Lewis酸性.用0.2 mol/L NaOH溶液和0.2 mol/L硝酸溶液通过碱-酸组合改性得到的催化剂DeSiAl-Y-0.2在环己酮肟液相重排反应中表现出较好性能.在以苯甲腈为溶剂、反应温度和时间分别为130℃和3 h的条件下,其环己酮肟转化率和己内酰胺选择性都达到了82.9%,分别比Y沸石母体提高了18%和1.5%.在DeSiAl-Y-0.2催化剂上初步开展了反应条件和溶剂效应的研究工作,从中可以看出研制用于环己酮肟液相重排反应的Y型沸石催化剂的关键在于提高其己内酰胺选择性. 相似文献
513.
Theoretical prediction on the synthesis of 2,3‐dihydropyridines through Co(III)‐catalysed reaction of unsaturated oximes with alkenes 下载免费PDF全文
Xiang‐Biao Zhang Bin‐Bin Yu Sheng‐Meng Si Song Wang 《International journal of quantum chemistry》2017,117(8)
Cobalt‐based catalysts can replace the homologous group‐9 rhodium‐based ones. Herein, we used density functional theory (DFT) calculations to predict the synthesis of 2,3‐dihydropyridines using α,β‐unsaturated oxime pivalates and alkenes catalysed by [Cp*CoOAc]+ instead of [Cp*RhOAc]+. The catalytic cycle involves reversible acetate‐assisted metalation‐deprotonation, migratory insertion of alkenes, and reductive elimination/N‐O cleavage. The migratory insertion of alkenes was determined to be the rate‐determining step, and the reaction is irreversible due to the strongly exergonic reductive elimination/N? O cleavage. When using the CF3‐substituted Cp*Co(III) catalyst, the apparent activation energy indicates that the title reaction can proceed at higher temperatures. Electron‐withdrawing substituent groups on Cp* facilitate the reaction. In contrast, substituting phenyl with the electron‐deficient p‐CF3‐phenyl at the 2‐position of α,β‐unsaturated oxime pivalate hinders the reaction, and so does the use of polarized alkenes with electron‐withdrawing substituent groups 相似文献
514.
Synthesis and conjugation of a triiodohydroxylamine for the preparation of highly X‐ray opaque poly(ε‐caprolactone) materials 下载免费PDF全文
Brooke A. Van Horn Lundy L. Davis Samantha E. Nicolau Emma E. Burry Victoria O. Bailey Fernanda D. Guerra Frank Alexis Daniel C. Whitehead 《Journal of polymer science. Part A, Polymer chemistry》2017,55(5):787-793
To address a need for highly X‐ray opaque biodegradable materials, a series of poly(ε‐caprolactone) derivatives were prepared using oxime post‐polymerization modification to conjugate two different iodinated hydroxylamines. These materials were synthesized with up to 32 wt. % iodine content and demonstrated improved X‐ray contrast relative to both the ketone precursors and previously reported monoiodinated materials. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 787–793 相似文献
515.
高选择性氧化环己烷(CHA)制备环己酮和环己醇(KA油)具有重要的工业价值和应用前景. 本文提出采用间歇电沉积法制备纳米MnOx催化剂负载多孔管式钛膜,构建电催化膜反应器(ECMR)催化氧化环己烷制备环己醇和环己酮. 利用场发射扫描电子显微镜(FESEM)、X射线衍射仪(XRD)和电化学工作站等表征手段对催化剂的结构与性能进行表征. 结果表明,间歇电沉积法制备的催化剂为纳米花球状γ-MnO2. 与基体钛膜相比,MnOx/Ti膜电极具有更优的电化学性能和传质性能. 此外,以MnOx/Ti电催化膜为阳极,不锈钢网为阴极构建ECMR. 当环己烷初始浓度30 mmol·L-1、反应温度30oC、停留时间34.3 min、电流密度2.3 mA·cm-2等条件下,ECMR环己烷转化率达25.6%,KA油总选择性高于99%. 同时,ECMR重复使用8次后表现较高催化稳定性. 相似文献
516.
517.
The title compound has been synthesized by the reaction of 3,3-dimethyl-1-(1H-1,2,4-triazol-1-yl)butan-2-one oxime with 2-chlorobenzyl chloride, and then treated with 65~68% HNO3. Its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to the monoclinic system, space group P21/c with a = 14.5481(8), b = 9.3351(5), c = 13.1911(7) , β = 98.9450(10)°, Z = 4, V = 1769.67(17) 3, Mr = 369.81, Dc = 1.388 g/cm3, S = 1.06, μ = 0.247 mm-1, F(000) = 776, the final R = 0.0352 and wR = 0.0960 for 3069 observed reflections (I > 2σ(I)). X-ray crystal structure presents the intramolecular N–H…O hydrogen bond. The packing is nearly parallel without π-π stacking interactions between two adjacent phenyl rings and stabilized by Van der Waals force. The preliminary bioassay shows that the title compound possesses fungicidal activity against Gibberella zeae at the dosage of 25 mg/L. 相似文献
518.
新型含吡啶环取代的吡唑肟醚类化合物的合成及生物活性研究 总被引:1,自引:0,他引:1
为了寻找新型高效低毒的农药先导化合物,通过N-吡啶基吡唑肟与2-氯-5-氯甲基吡啶的缩合反应,合成了一系列含吡啶环取代的吡唑肟醚类化合物.目标化合物的结构均经1H NMR,13C NMR和元素分析确证.初步生物活性试验结果表明,部分化合物具有一定的杀菌、杀虫和植物生长调节活性.如化合物5e在浓度为50 μtg/mL时对番茄早疫的抑制率为61.4%;化合物5j在浓度为50 μg/mL时对花生褐斑的抑制率为60.2%;化合物5i在浓度为500 μg/mL时对蚜虫表现出50.3%的杀死率;化合物5f在浓度为10 μg/mL时对黄瓜子叶生根表现出71.0%的促进生长作用. 相似文献
519.
Analysis of femtosecond laser ionization/dissociation of polyatomic molecule C6H10O from one-colour pump-probe measurement 下载免费PDF全文
This paper reports that a one-colour fs pump-probe measurement has been carried out for studying photoionization/photodissociation of cyclohexanone (C6H10O) in intense laser field. Two of the fragments from cyclohexanone, C2H3+ and C3H3+ , are studied under 800 nm laser pump-probe and the results obtained show similar time evolutions. It proposes a feasible model for analysing the experimental observations of the one-colour fs pump-probe measurement. The results demonstrate that as an intermediate product, the excited molecular parent ions play a very important role in photionization/photodissociation processes in intense laser field. 相似文献
520.
With the aim of discovering a lead compound for pyridine‐based fungicide bearing adamantane moiety, a series of novel O‐alkyl/benzyl‐1‐(adamantan‐1‐yl)‐2‐(pyridin‐3‐yl)ethan‐1‐one oximes were synthesized from 3‐methylpyridine, ethyl (adamantan‐1‐yl)carboxylate, and alkoxyamine or benzoxyamine hydrochloride. The in vitro antifungal activity against four pathogenic fungi was evaluated, and some compounds exhibited good antifungal activity. Compounds 3d and 3f demonstrated strong activity against Sclerotinia sclerotiorum, with EC50 values of 11.25 and 12.87 μg/mL, respectively; 3b , 3c, and 3k had notable activity against Botrytis cinerea, with EC50 values of 12.78, 12.57, and 11.97 μg/mL, respectively. For Rhizoctonia Solani, 3d and 3g showed sufficient activity with EC50 values of 9.66 and 8.90 μg/mL, respectively. In addition, 3d and 3g demonstrated moderate activity against Colletotrichum orbiculare, with EC50 values of 14.32 and 15.83 μg/mL, respectively. 相似文献