共查询到20条相似文献,搜索用时 187 毫秒
1.
2.
3.
4.
以二苯硫醚为主要原料,以过氧化氢为氧化剂,在室温条件下氧化得到了二苯亚砜.然后,二苯亚砜与二苯硫醚在硫酸的作用下,进行缩合反应制备了双[(4-二苯硫)苯]硫醚-双-六氟磷酸盐,收率由文献报道的39%提高到75%;对其结构进行了UV、IR、H NMR和元素分析. 相似文献
5.
在氯合5,10,15,20-四苯基卟吩合铁(III)[TPPFe(III)Cl]催化下, 带有不同取代基的亚碘酰苯和亚碘酰苯的衍生物作充氧化剂对环己烷进行了仿生单充氧化反应的研究.取代亚碘酰苯中对位取代基的电子效应和间位取代基的电子及立体效应对氧化产物环己醇的产率有良好线性相关性. 亚碘酰苯的衍生物苯亚碘酸二醋酐与苯亚碘酸单对甲苯磺酸酐对环己烷的充氧化能力和邻、间、对亚碘酰苯甲酸与邻亚碘酰苯甲酸酯相似, 环己醇产率接近零. 从而提出亚碘酰苯甲酸及邻亚碘酰苯甲酸酯存在分子内或分子间I(oh)oco成键结构的论点. 相似文献
6.
7.
对硝基苯磺酰基乙酸酯与芳香醛的缩合反应 总被引:1,自引:0,他引:1
对硝基苯磺酰基乙酸酯与芳香醛在六氢吡啶醋酸盐催化下发生缩合反应生成α,β-不饱和砜,研究了催化剂对反应影响,发现DPA(3-Dimethylaminophenylpropylamine)是最有效的催化剂,可以替代六氢吡啶。在NaCl/DMSO/H2O体系中,缩合产物2-(对硝基苯磺酰基)-3-苯丙烯酸乙酯在185℃反应,得到脱羧物E-2-(对硝基)苯磺酰基苯乙烯。用1HNMR确证了缩合产物构型为E。 相似文献
8.
9.
以环十二酮为原料, 经过α-取代反应生成中间体α-苯磺酰基环十二酮, 先与NH2OH作用成肟然后酯化反应合成了20个未见文献报道的α-苯磺酰基环十二酮肟酯衍生物(8), 其化学结构经1H NMR, IR和元素分析确证. 初步生物活性测定结果显示, 部分化合物具有一定的除草活性, 如α-苯磺酰基环十二酮肟-2,4-二氯苯氧乙酸酯(8p)在浓度为100和1 mg/L时对马唐(Digitaria sanguinalis)的抑制率分别为100%和80.07%; 对苘麻(Abutilon theophrasti)的抑制率分别为100%和88.70%. 毒力测定结果显示, OE16对马唐的IC50值和苘麻的IC50值分别为0.192和0.151 mg/L. 相似文献
10.
11.
甲酸是一种重要的化工原料,以可再生生物质为原料,通过催化氧气氧化制备甲酸具有重要意义。对于不溶于水的生物质原料的转化,采用可溶于水的均相催化剂体系证明是有效的。本文总结了均相催化剂体系(包括含钒杂多酸、含钒杂多酸+H2SO4、含钒杂多酸基离子液体、NaVO3+H2SO4、VOSO4、NaVO3-FeCl3+H2SO4、FeCl3+H2SO4等)在催化氧气氧化生物质(包括生物质模型化合物、纤维素、木材、秸秆和玉米芯等)制备甲酸方面的研究,分析了其转化的过程和机理。最后,指出了目前催化氧化生物质制备甲酸存在的问题和挑战。 相似文献
12.
SCR脱硝过程中SO催化氧化的原位红外研究 《燃料化学学报》2015,43(8):1018-1024
采用工业用V2O5-WO3/TiO2催化剂,基于傅里叶原位红外光谱(FT-IR)技术考察SO2的氧化过程及烟气组分对SO2氧化行为的影响;结果表明,SO2在催化剂表面氧化主要是首先吸附在催化剂表面V2O5活性位上,占据其O原子,以SO2-3形式存在,后与催化剂表面V5+-OH发生反应,生成金属硫酸盐(VOSO4)中间产物,O2重新氧化催化氧化过程中由于被SO2夺取O原子而被还原的V2O5物种,使V4+转化为V5+,促进金属硫酸盐(VOSO4)向SO3转化;SO2与NO、NH3的竞争吸附阻碍SO2在V2O5活性点位上的氧化;在SCR中,NO的脱除与SO2的氧化是相互抑制的关系。 相似文献
13.
X-ray absorption spectra at the chromium K-edge are reported for a number of selected chromium compounds of known chemical structure. The spectra were obtained with use of synchrotron radiation available at the
ectron
tretcher
ccelerator ELSA in Bonn. The compounds studied include the tetrahedrally coordinated compounds Ca2Ge0.8Cr0.2O4, Ba2Ge0.1Cr0.9O4, Sr2CrO4, Ca2(PO4)x(CrO4)1−xCl (x=0.25,0.5), Ca5(CrO4)3Cl, CrO3, the octahedrally coordinated compounds Cr(II)-acetate, CrCl3, CrF3, Cr2O3, KCr(SO4)2 · 12H2O, CrO2 and cubic coordinated metallic chromium. In these compounds chromium exhibits a wide range of formal oxidation states (0 to VI). The absorption features in the near edge region are shown to be characteristic of the spatial environment of the absorbing atom. The occurrence of a single pre-edge line easily allows one to distinguish between tetrahedral and octahedral coordination geometry, whereas the energy position of the absorption edge is found to be very sensitive to the valency of the excited chromium atom. Calculations of the ionisation potential of Cr in different oxidation states using the non-relativistic Hartree–Fock method (Froese–Fischer) confirm that the ionisation limit shifts to higher energy with increasing Cr valency. More detailed information on the electronic structure of the different compounds is gained by real-space full multiple scattering calculations using the FEFF8 code. 相似文献
14.
Jonathan P. Blitz Nigel T. Lucas Mark G. Humphrey 《Journal of organometallic chemistry》2002,650(1-2):133-140
The 60-electron tetrahedral clusters W2Ir2(μ-L)(CO)8(η5-C5H4Me)2 [L=dppe (2), dppf (3)] have been prepared from reaction between W2Ir2(CO)10(η5-C5H4Me)2 (1) and the corresponding diphosphine in 52 and 66% yields, respectively. A structural study of 2 reveals that three edges of a WIr2 face are spanned by bridging carbonyls, that the iridium-ligated diphosphine coordinates diaxially and that the tungsten-bound methylcyclopentadienyls coordinate axially and apically with respect to the plane of bridging carbonyls. A structural study of 3 reveals that the dppf ligand bridges an Ir---Ir bond which is also spanned by a bridging carbonyl; tungsten-ligated methylcyclopentadienyl ligands and terminal carbonyls result in electronic asymmetry (17e and 19e iridium atoms) in the electron-precise cluster. Both clusters show two reversible one-electron oxidation processes and an irreversible two-electron reduction; the dppf-containing cluster 3 has a further, irreversible, one-electron oxidation process. UV–vis-NIR spectroelectrochemical studies of the 2→2+→22+ progression reveal the appearance of a low-energy transition on oxidation to 2+ which persists on further oxidation to 22+. 相似文献
15.
铬铁电化学氧化法是一种新的制备铬酸钠的方法,然而高碳铬铁在NaOH水溶液中的电化学氧化过程尚不明确。 采用循环伏安法(CV)、稳态极化法(LSV)等电化学测试方法对金属铬、高碳铬铁在NaOH水溶液中的电化学氧化过程进行研究,通过扫描电子显微镜(SEM)、能量散射谱(EDS)和X射线光电子能谱(XPS)对高碳铬铁电解后固相产物表征,判断固相产物的组成。 结果表明,高碳铬铁不同于金属铬的电氧化过程,它在NaOH溶液中通过Cr(0)→Cr(Ⅵ)的电氧化方式生成铬酸钠,中间产物Cr(OH)3和Fe(0)发生电化学反应生成稳定的FeCr2O4。 随着NaOH浓度的增加,电势较低时,受高碳铬铁中Fe(0)的影响,高碳铬铁容易在NaOH水溶液中发生钝化;当电势足够正时,钝化膜溶解,生成铬酸钠、氢氧化铁和亚铬酸亚铁,同时,阳极表面有氧气析出。 高碳铬铁电化学氧化制备铬酸钠的适宜条件:碱浓度≥2 mol/L,阳极电势≥1.6 V(vs.SCE)。 相似文献
16.
考察了在焦磷酸盐水溶液中用O3氧化Ce(Ⅲ),生成的Ce(Ⅳ)与P2O74-的作用情况,并对不同条件下所得的固体进行了研究。 相似文献
17.
Elena V. Frolova M. Ivanovskaya V. Sadykov G. Alikina A. Lukashevich S. Neophytides 《Progress in Solid State Chemistry》2005,33(2-4):317-325
Structural peculiarities of Ce–Zr–La–O and Ce–Zr–La–O/Ru samples in mean of catalytic properties are compared. The samples (Ce:Zr = 1:1, La = 10÷30 mol.%, Ru = 1.5 wt.%) were obtained by sol–gel method (X-samples) and co-precipitation (P-samples). It is shown that Ce0.45Zr0.45La0.1O2−δ/Ru X-samples are characterized by high thermal stability and the highest catalytic activity in partial methane oxidation reaction. According to XRD, BET, FTIR, EPR and XPS data it is concluded that the difference in the samples catalytic activity is caused by various disposition of Ru-containing phase on the support surface. The distinction in the dimension of Ru-containing particles (3D or 2D) is conditioned by structural peculiarities of Ce0.45Zr0.45La0.1O2−δ and Ce0.35Zr0.35La0.3O2−δ P- and X-samples. 相似文献
18.
Ruthenium(II) perchlorate complexes, [Ru(dppm)3(ClO4)]ClO4 1, [Ru(dppe)3(ClO4)]ClO4 2, and [Ru(dpae)3(ClO4)]ClO4 3, catalyse the selective homogeneous oxidation of alkenes with TBHP and H2O2 as oxidizing agents. Oxidation of cyclohexene with TBHP gave 2-cyclohexene-1-ol, 2-cyclohexenone and 1-(tert-butylperoxy)-2-cyclohexene. The homogeneous liquid phase oxidation of cyclohexene with TBHP shows appreciable solvent effect. Styrene on oxidation with TBHP gave benzaldehyde as the major product and styrene oxide as the minor product. Oxidation with H2O2 is radical-initiated and gives low conversion to products. TBHP and H2O2 are compared for their oxidizing ability and TBHP is more effective than H2O2 as an oxidizing agent. Linear and long chain alkenes are not efficiently oxidized. Cyclooctene and trans-stilbene are oxidized to the corresponding epoxides. 相似文献
19.
T. Stuchinskaya N. Kundo L. Gogina U. Schubert A. Lorenz V. Maizlish 《Journal of molecular catalysis. A, Chemical》1999,140(3):128-240
The catalytic activity of cobalt(II) 2,9,16,23-tetrasulphophthalocyanine and cobalt(II) 2,9,16,23-tetra(chlorosulphonyl)phthalocyanine covalently bonded to a TiO2 matrix by sol–gel processing was investigated for sulfide and ethanethiol (CH3CH2SH) liquid-phase oxidation. A comparison of the kinetic data as well as the state of active component by using electron spectroscopy in dependence on precursors was carried out. Kinetic data shows that the most stable and active catalysts for ethanethiol oxidation are both CoPc(SO3H)4 and CoPc(SO2Cl)4 in TiO2 from Ti(OiPr)4, whereas in the case of Na2S oxidation in neutral medium the activity of the former is higher. 相似文献
20.
Liangshiu Lee Chun-Hsien Yuan 《Journal of photochemistry and photobiology. A, Chemistry》1993,70(3):261-263
Co(tptn)3+ and Co(tpen)3+ (where tptnN,N,N′,N′-tetrakis(2-pyridylmethyl)-1,3-propanediamine and tpen N,N,N′,N′-tetrakis(2-pyridylmethyl)ethylenediamine) are demonstrated to have a similar photosensitization capacity to other caged Co(III) complexes such as Co(sepulchrate)3+. In oxygen-saturated aqueous solutions at pH 4.0, a photoassisted oxidation of I− to I3− by O2 is obtained with a turnover number of greater than 12 for both Co(tptn)3+ and Co(tpen)3+. Quantum yields for the formation of
I3− are 8.7x 10−4 and 1.6x 10−2 respectively at pH 4.0 in solution with a constant supply of air. 相似文献