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1.
Bipolar membranes were reported to split alcohol into alkoxide ions and H+; however, there is no direct evidence for ethanol splitting, i.e., the existence of ethoxide ions. This work uses ethanol for alcohol splitting test and 1H NMR for the identification of ethoxide ions. According to the spectra analysis, the chemical shifts of proton H, δ 3.736–3.666 (q, 2H) and δ 1.255–1.209 (t, 3H) can only be ascribed to CH3CH2O−. Therefore, this work first proves ethanol splitting in bipolar membranes by detecting the existence of sodium ethoxide. To further extend the application of electrodialysis to non-aqueous systems (as in organic synthesis), membranes of better solvent-resistance are needed to be developed. 相似文献
2.
A highly efficient FeCl3-catalyzed alkylation of various active methylene compounds with various benzylic or allylic alcohols under mild conditions has been developed. The reaction was carried out in the presence of a catalytic amount of anhydrous FeCl3 (10 mol %) under reflux in methylene chloride. High to excellent yields were obtained. 相似文献
3.
The FeCl3-catalyzed C3-selective Friedel-Crafts alkylation of indoles using allylic, benzylic and propargylic alcohols has been developed. The reaction was performed in the presence of a catalytic amount of inexpensive anhydrous FeCl3 (10 mol %) in nitromethane under mild conditions. This method can also be used for the alkylation of pyrrole. 相似文献
4.
Cr-doped SrTi1−xCrxO3 (x=0.00, 0.02, 0.05, 0.10) powders, prepared by solvothermal method, were further characterized by ultraviolet-visible (UV-vis) absorption spectroscopy. The UV-vis spectra indicate that the SrTi1−xCrxO3 powders can absorb not only UV light like pure SrTiO3 powder but also the visible-light spectrum (λ>420 nm). The results of density functional theory (DFT) calculation illuminate that the visible-light absorption bands in the SrTi1−xCrxO3 catalyst are attributed to the band transition from the Cr 3d to the Cr 3d+Ti 3d hybrid orbital. The photocatalytic activities of chromium-doped SrTiO3 both under UV and visible light are increased with the increase in the amounts of chromium. 相似文献
5.
Graphite-like carbon nitride (g-C3N4) based heterostrutures has attracted intensive attention due to their prominent photocatalytic performance. Here, we explore the g-C3N4/SnS2 coupling effect on the electronic structures and optical absorption of the proposed g-C3N4/SnS2 heterostructure through performing extensive hybrid functional calculations. The obtained geometric structure, band structures, band edge positions and optical absorptions clearly reveal that the g-C3N4 monolayer weakly couples to SnS2 sheet, and forms a typical van der Waals heterojunction. The g-C3N4/SnS2 heterostructure can effectively harvest visible light, and its valence band maximum and conduction band minimum locate in energetically favorable positions for both water oxidation and reduction reactions. Remarkably, the charge transfer from the g-C3N4 monolayer to SnS2 sheet leads to the built-in interface polarized electric field, which is desirable for the photogenerated carrier separation. The built-in interface polarized electric field as well as the nice band edge alignment implys that the g-C3N4/SnS2 heterostructure is a promising g-C3N4 based water splitting photocatalyst with good performance. 相似文献
6.
A simple, inexpensive, environmentally friendly and high yielding amidation reaction of benzylic and allylic alcohols with primary amides using a catalytic amount of FeCl3 (5 mol %) is described. Direct substitution of various amides such as benzamide, sulfonamide, acetamide and acrylamide is reported, and this method also works on a large scale in high yield. 相似文献
7.
A new method for the synthesis of propargylated aromatic compounds is developed. The reaction was carried out at room temperature in the presence of a catalytic amount of FeCl3 in acetonitrile, high product yields were obtained with excellent regioselectivity and the reaction proceeded smoothly without exclusion of moisture or air. 相似文献
8.
Hiroyuki ShinoharaMotohiro Sonoda Shingo AtobeHaruna Masuno Akiya Ogawa 《Tetrahedron letters》2011,52(47):6238-6241
IrCl3·3H2O or FeCl3-catalyzed convenient synthesis of 3-hydroxyphthalates has been achieved by a Diels-Alder reaction of furans with dimethyl acetylenedicarboxylate, followed by ring-opening aromatization reaction of the Diels-Alder adducts, 7-oxabicyclo[2.2.1]hepta-2,5-diene derivatives. In addition, 7-azabicyclo[2.2.1]hepta-2,5-diene derivative, derived from N-Boc-pyrrole and dimethyl acetylenedicarboxylate, also converted into 3-aminophthalate derivative. 相似文献
9.
Georgiy B. Shul’pin Camilla C. Golfeto Lidia S. Shul’pina 《Tetrahedron letters》2005,46(27):4563-4567
The H2O2-FeCl3-bipy system in acetonitrile efficiently oxidises alkanes predominantly to alkyl hydroperoxides. Turnover numbers attain 400 after 1 h at 60 °C. It has been assumed that bipy facilitates proton abstraction from a H2O2 molecule coordinated to the iron ion (these reactions are stages in the catalytic cycle generating hydroxyl radicals from the hydrogen peroxide). Hydroxyl radicals then attack alkane molecules finally yielding the alkyl hydroperoxide. 相似文献
10.
The introduction of a tert-butyl group at position 2 of the A ring of estrogens leads to enhanced antioxidant effects. Therefore, a generally applicable and convenient method was developed using FeCl3–graphite or anhydrous FeCl3 as catalysts in the Friedel-Crafts alkylation of estrogens. The rates and yields of the alkylations were lower with FeCl3–graphite than with anhydrous FeCl3, but the regioselectivity of the former were higher. Both catalysts proved to be more effective than typical AlCl3. 相似文献
11.
Dinesh N. Sawant 《Tetrahedron letters》2010,51(20):2758-381
Conditions for a FeCl3/PPh3-catalyzed and palladium-, copper-, amine free-Sonogashira coupling reaction of aryl halides with terminal alkynes are reported. The protocol was applicable to a wide variety of substituted aryl iodides and alkynes with different steric and electronic properties and gave excellent yields of the desired coupling products. 相似文献
12.
Ahmed Kamal B. Rajendra Prasad A. Venkata Ramana A. Hari Babu K. Srinivasa Reddy 《Tetrahedron letters》2004,45(17):3507-3509
The tetrahydroquinoline moiety is an important structural component of a number of natural products. The reaction of aryl azides with 3,4-dihydro-2H-pyran in the presence of FeCl3-NaI affords the corresponding tetrahydroquinoline derivatives in an efficient manner. Most of the cyclizations exhibited cis selectivity. 相似文献
13.
Xu Zhili Gao Haifeng Qian Mengping Yu Ye Wan Guoxiong Chen Baokang 《Radiation Physics and Chemistry》1993,42(4-6):963-966
Single-sheet bipolar membranes have been prepared by grafting of styrene into radiation peroxidized LDPE films, which were then chlorosulfonated from one side, chloromethylated and quaternized from the other side. Various monomer systems were investigated and optimized. Obtained bipolar membranes were characterized by their specific electrical resistance, static potentials, rectification properties and water splitting capabilities. 相似文献
14.
Giuliana Gervasio Domenica Marabello Enrico Sappa Andrea Secco 《Journal of Cluster Science》2007,18(1):67-85
Ru3(CO)12 has been reacted with the compounds hex-1-en-3-yne [EtC≡CCH=CH2], 2-methyl-hex-1-en-3-yne [EtC≡CC(=CH2)CH3] and with 3(ethoxy-silyl)propyl isocyanate [(EtO)3Si(CH2)3NCO] and the compound tb [(EtO)3Si(CH2)3NHC(=O)OCH2C≡CCH2OC(=O)NH(CH2)3Si(OEt)3] in hydrocarbon solution. Some reactions in CH3OH/KOH solution (followed by acidification) have also been performed.
The main products of the reactions with ene-ynes are the clusters Ru3(CO)6(μ-CO)2L2 (L = C6H8, C7H10) and their demolition products, the “ferrole” Ru2(CO)6L2 complexes. One of the isomers of Ru3(CO)6(μ-CO)2L2, and Ru2(CO)6L2 (L = C7H10) have been reacted with vinyl-triethoxysilane [(EtO)3SiCH=CH2]: these reactions did not afford complexes containing new carbon–carbon bonds or triethoxy-silyl groups. Only polymerization
of vinyl-triethoxysilane occurred.
The reactions of Ru3(CO)12 with triethoxysilyl-propyl-isocyanate and tb (in the presence of Me3NO) lead to the same products, that is the isomeric complexes (μ-H)Ru3(CO)9[C=N(H)(CH2)3Si(OEt)3] with a “perpendicular” ligand (complex 3, as proposed on the basis of spectroscopic results) and (μ-H)Ru3(CO)9[HC=N(CH2)3Si(OEt)3] with a “parallel” ligand (complex 4, as confirmed by a X-ray analysis). The reaction pathways leading to these products are discussed. Complex 4 has been reacted with tetraethyl orthosilicate and the resulting material has been characterized. These reactions are part
of a study on the synthesis of inorganic-organometallic materials through sol–gel techniques.
This paper is dedicated to Prof. Gunther Schmid in the occasion of his 70th birthday. 相似文献
15.
Yiqing Feng Hanyun Cheng Jin Han Xiuzhen Zheng Yangyang Liu Yang Yang Liwu Zhang 《中国化学快报》2017,28(12):2254-2258
Converting solar energy into valuable hydrogen and hydrocarbon fuels through photoelectrocatalytic water splitting and CO_2 reduction is highly promising in addressing the growing demand for renewable and clean energy resources. However, the solar-to-fuel conversion efficiency is still very low due to limited light absorption and rapid bulk recombination of charge carriers. In this work, we present chlorophyll(Chl) and its derivative sodium copper chlorophyllin(ChlCuNa), as dye sensitizers, modified BiVO_4 to improve the photoelectrochemical(PEC) performance. The photocurrent of BiVO_4 is surprisingly decreased after a direct sensitization of Chl while the sensitization of ChlCuNa obviously enhances photocurrent of BiV04 electrodes by improved surface hydrophilicity and extended light absorption.ChlCuNa-sensitized BiV04 achieves an improved H_2 evolution rate of 5.43 μmol h~(-1) cm~(-2) in water splitting and an enhanced HCOOH production rate of 2.15 μmol h~(-1) cm~(-2) in CO_2 PEC reduction, which are1.9 times and 2.4 times higher than pristine BiVO_4, respectively. It is suggested that the derivative ChlCuNa is a more effective sensitizer for solar-to-fuel energy conversion and CO_2 utilization than Chl. 相似文献
16.
采用柠檬酸络合法制备铋层钙钛矿K0.5La0.5Bi2Ta2O9 (KLBT), 通过酸化处理得到质子化层状钙钛矿H1.9K0.3La0.5Bi0.1Ta2O7(HKLBT)光催化剂, 并通过热重-差热(TG-DSC)、X射线衍射(XRD)、紫外-可见漫反射(DRS)、X射线光电子能谱(XPS)等技术对其进行了表征和分析.考察了前驱体KLBT的不同焙烧温度对HKLBT制氢活性的影响. 结果表明, 柠檬酸络合法能在较低温度下合成高结晶度纯相HKLBT, 前驱体经900℃焙烧制备的HKLBT催化剂活性最高, 在纯水中的产氢速率达236.6μmol·h-1; 长时间活性测试表明HKLBT具有完全分解水同时产氢产氧能力,且具有较好的稳定性. 相似文献
17.
CoPc(COOH)8-SA/mCS双极膜的制备及表征 总被引:2,自引:0,他引:2
分别用Fe3+离子和戊二醛作为交联剂对海藻酸钠(SA)阳膜层和壳聚糖(CS)阴膜层进行改性, 制备了八羧基钴酞菁-海藻酸钠/改性壳聚糖(CoPc(COOH)8-SA/mCS)双极膜(BPM). 在海藻酸钠阳膜层中添加八羧基钴酞菁以提高阳膜的离子交换容量, 促进中间层水的解离. 用傅立叶红外(FT-IR)光谱、扫描电镜(SEM)等方法对制备的双极膜进行了表征. 实验结果表明, 经八羧基钴酞菁改性后, 阳离子交换膜层的离子交换容量、H+离子透过率均获得提高. 与Fe3+离子改性或二茂铁离子改性的mSA/mCS双极膜相比, CoPc(COOH)8-SA/mCS双极膜的交流阻抗、电阻压降(IR降)和溶胀度降低. 当电流密度高达105 mA·cm-2时, CoPc(COOH)8-SA/mCS双极膜的IR降仅为0.7 V. 相似文献
18.
Rong-Qiang Fu Tong-Wen Xu Yi-Yun Cheng Wei-Hua Yang Zhong-Xiao Pan 《Journal of membrane science》2004,240(1-2):141-147
Starburst dendrimer polyamidoamine (PAMAM) with ellipsoidal or spheroidal shape is structure-regular and has much more amino groups than conventional polymers. This paper investigates the possibility of these amino groups on water dissociation in a bipolar membrane interface. To do this, a bipolar membrane is prepared by casting the solution of sulfonated poly(phenylene oxide) (SPPO) in dimethyl formamide (DMF) on a commercial anion exchange membrane that is immersed in PAMAM aqueous solution in advance. The existence of PAMAM adsorbed on the membrane is proved by X-ray photoelectron spectroscopy (XPS), and the adsorption amount is evaluated by weighting method. The junction thickness of the prepared bipolar membrane is determined by electrochemical impedance spectroscopy (EIS), and the performance is evaluated by current–voltage curves. The experiments show that both the generation and concentration of PAMAM would strongly affect the characteristics of the bipolar membranes. There exists a transitional concentration for various generations PAMAMs to catalyze effectively the water dissociation, and above or below the transitional concentration the performance of bipolar membranes is decreasing. The higher the generation, the lower the concentration. Moreover, at a fixed solution concentration, there is not the simple relation of monotone decreasing or increasing between the performance of bipolar membranes and the generations of PAMAMs. All these can be explained according to the characteristics of PAMAMs combined with available water dissociation theory. 相似文献
19.
Valentine G. Nenajdenko Georgy N. Varseev Elisabeth S. Balenkova 《Journal of fluorine chemistry》2005,126(6):907-913
The new approach of catalytic olefination reaction (COR) has been used to convert aromatic and aliphatic aldehydes and ketones to 2-bromo-3,3,3-trifluoroprop-1-enes by the treatment of corresponding hydrazones with CBr3CF3 under copper(I) catalysis conditions. The reaction proceeds stereoselectively, the target alkenes were obtained in good yields. 相似文献
20.
Rachid El Moussaoui G rald Pourcelly Maurice Maeck Henry D. Hurwitz Claude Gavach 《Journal of membrane science》1994,90(3):283-292
The influence of co-ion leakage through a bipolar membrane on both I–V response and current efficiency of water dissociation was studied. The monofilm bipolar membrane was synthetized from a pretreated ETFE film functionalized by quaternized ammonium groups on one side and sulphonic groups on the other. The co-ion leakage of this bipolar membrane immersed in NaCl solutions was measured by means of radiotracers. The results showed that the greater the co-ion leakage, the lower was the current efficiency of water dissociation. A theoretical analysis of ion transfer through the bipolar membrane pointing out the effect of boundary layer on the limiting leakage current is presented. 相似文献