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991.
C12-s-C12•2Br和C12En混合水溶液的胶团化行为 总被引:3,自引:0,他引:3
季铵盐二聚表面活性剂C12 s C12•2Br(s=2、3、4、6)和非离子表面活性剂C12E10或C12E23在水溶液中生成混合胶团.其临界胶团总浓度cmcT值介于二元复配体系中各组分的临界胶团浓度和之间.当添加少量非离子型表面活性剂(在水溶液中的摩尔分数α2=0.1)时,混合胶团中C12E10或C12E23的摩尔分数均已超过0.35;随着溶液中非离子型表面活性剂含量的增大,混合胶团中逐渐以C12E10或C12E23成分为主. 相似文献
992.
Ultrafine rare earth molybdenum (La–Mo and Ce–Mo) complex oxide particles have been synthesized by the sol–gel process using citric acid as complexing agent. The influence of preparation conditions such as thermal treatment temperature (T), molar ratio of citric acid to metallic ions (L/M), and pH value of the starting solution on the oxide particle size has been studied. The formation of La2Mo2O9and Ce2Mo3O12has been investigated using XRD, DTA–TG, FT-IR, TEM, and BET surface area measurements. It is shown that the morphology and structure of the oxide particles are significantly dependent on the preparation conditions. The influence of different preparation methods on the particle size of La–Mo and Ce–Mo oxides is also discussed. 相似文献
993.
The optimized structures and proton transfer reactions of 3-methyl-5-hydroxyisoxazole and its water complexes (3-M-5-HIO · (H2O)n · (n = 0–3)) were computed at B3LYP and MP2 theoretical level. The results indicates that 3-M-5-HIO has four isomers (Ecis, Etrans, K1 and K2), and the keto tautomer, and K2 is the most stable isomer in the gas phase. Hydrogen bonding between 3-M-5-HIO and the water molecules can dramatically lower the barrier by the concerted transfer mechanism. Ecis · (H2O)3 → K1 · (H2O)3 and Ecis · (H2O)2 → K2 · (H2O)2 is found to be very efficient. Comparing with the proton transfer mechanism of 5-HIO shows that the methyl substitution prevents the intramolecular proton transfer. 相似文献
994.
Yuan Yuan Wang Wei Li Li Yi Dai 《中国化学快报》2007,18(10):1187-1190
Cationic ring-opening polymerization of 3,3-bis(chloromethyl)oxacyclobutane catalyzed by BF_3·OEt_2 was carried out in ionic liquids [bmim]BF_4 and [bmim]PF_6.The influences of BCMO concentration and molar ratio of BCMO/BF_3·OEt_2 on the molecular weights and yield of PBCMO were investigated.The polymerization in ionic liquids proceed to high conversions,although molecular weights are limited,similar to polymerization in organic solvent such as CH_2Cl_2.Follow a viewpoint of green chemistry, we feel ionic liquid [bmim]BF_4 is superior to [bmim]PF_6.Extracting [bmim]PF_6 from the product using organic solvent as extractant limits its advantage as a green reaction media. 相似文献
995.
Fine particle superacidic sulfated zirconia (SO42−/ZrO2, S-ZrO2) was synthesized by ameliorated method, and composite membranes with different S-ZrO2 contents were prepared by a recasting procedure from a suspension of S-ZrO2 powder and Nafion solution. The physico-chemical properties of the membranes were studied by ion exchange capacity (IEC) and liquid water uptake measurements, scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis, thermogravimetry–mass spectrometry (TG–MS) and Fourier transform infrared (FT-IR) spectroscopy. The results showed that the IEC of composite membrane increased with the content of S-ZrO2, S-ZrO2 was compatible with the Nafion matrix, the incorporation of the S-ZrO2 could increase the crystallinity and also improve the initial degradation temperature of the composite membrane. The performance of single cell was the best when the S-ZrO2 content was 15 wt.%, and achieved 1.35 W/cm2 at 80 °C and 0.99 W/cm2 at 120 °C based on H2/O2 and at a pressure of 2 atm, the performance of the single cell with optimized S-ZrO2 was far more than that of the Nafion at the same condition (e.g. 1.28 W/cm2 at 80 °C, 0.75 W/cm2 at 120 °C). The 15 wt.% S-ZrO2/Nafion composite membrane showed lower fuel cell internal resistance than Nafion membranes at high temperature and low relative humidity (RH). 相似文献
996.
运用三足四齿配体三(2-甲基吡啶)胺(TPA)或三(2-甲基苯丙咪唑)胺(TBA),得到两个双核铁(III)配合物,[Fe2L2(μ2-O)(μ2-p-NH2-C6H4COO)]3+
(L = TPA, 1 和 L = TBA,
2)。两个配合物均为单斜晶系,空间群为P2(1)/c.晶胞参数 1: a =
1.4529(4), b = 1.6622(5), c = 2.0625(6) nm, β= 100.327(5)º,
V = 4.900(3) nm3, z = 4, F(000) = 2344, 分子量Mr = 1142.91, Dc
= 1.549 g/cm3, R1 = 0.0544,
R2 = 0.0962. 2: a = 1.3378(4), b = 2.1174(7), c =
2.4351(7) nm, β= 97.315(6)º, V = 6.842(4) nm3,
z = 4, F (000) = 3116, 分子量Mr = 1505.08, Dc
= 1.444 g/cm3, R1 = 0.0793, R2 = 0.1623. 在两个双核铁(III)配合物中,中心的三价铁和配体TPA或TBA上的四个氮原子和两个氧原子通过不同的桥形成一个畸变的八面体构型。 相似文献
997.
Pil Kim Younghun Kim Taewook Kang In Kyu Song Jongheop Yi 《Catalysis Surveys from Asia》2007,11(1-2):49-58
Mesoporous materials have attracted considerable attention for use as a catalyst or a catalyst support due to their remarkable
textural properties such as high surface area and large pore volume with a narrow pore size distribution. Many efforts have
been made to design mesoporous materials for use in heterogeneous catalyst systems. Recent progress and results regarding
the preparation of nickel-mesoporous materials and their application to the hydrodechlorination of chlorinated organic compounds
were discussed in this review. Mesoporous materials were used as a support for nickel catalyst or a nickel-incorporated mesoporous
catalytic material in this work. Two research areas were described and discussed in this review. One is the preparation of
mesoporous alumina-supported nickel catalysts and their application to the hydrodechlorination of 1,2-dichloropropane and
o-dichlorobenzene. The other is the preparation of mesoporous silica-supported nickel catalysts and their application to the
hydrodechlorination of 1,1,2-trichloroethane and chlorobenzene. 相似文献
998.
Si-Tai Zheng Huan-Huan Yin Zhao-Guang Ma Nan-Li Sheng Tian-Guang Zhan Xiao-Yang Yan Jiecheng Cui Li-Juan Liu Kang-Da Zhang 《中国化学快报》2019,30(3):707-709
Photoresponsive supramolecular hydrogel was fabricated from a small azobenzene-bridged dicationic pyridinium salt in the aqueous solution. The UV-vis light triggered reversible gel-sol transformation of such low-molecular-weight supramolecular hydrogel was systematically investigated through various analytical techniques. 相似文献
999.
The cleavage of a disulfide bond and the redox equilibrium of thiol/disulfide are strongly related to the levels of glutathione (GSH)/oxidized glutathione (GSSG) or mixed disulfides in vivo. In this work, the cleavage of a disulfide bond in GSSG induced by a platinum(II) complex [Pt(Met)Cl2] (where Met = methionine) was studied and the cleavage fragments or their platinated adducts were identified by means of electrospray mass spectrometry, high-performance liquid chromatography, and ultraviolet techniques. The second-order rate constant for the reaction between [Pt(Met)Cl2] and GSSG was determined to be 0.4 M(-1) s(-1) at 310 K and pH 7.4, which is 100- and 12-fold faster than those of cisplatin and its monoaqua species, respectively. Different complexes were formed in the reaction of [Pt(Met)Cl2] with GSSG, mainly mono- and dinuclear platinum complexes with the cleavage fragments of GSSG. This study demonstrated that [Pt(Met)Cl2] can promote the cleavage of disulfide bonds. The mechanistic insight obtained from this study may provide a deeper understanding on the potential involvement of platinum complexes in the intracellular GSH/GSSG systems. 相似文献
1000.
The compounds Ce(10)Cl(4)Ga(5) and Ln(3)ClGa(4) (Ln = La, Ce) were synthesized from stoichiometric mixtures of Ln, LnCl(3), and Ga under Ar atmosphere in sealed Ta ampules at 910-1020 degrees C for 25-26 days. Ce(10)Cl(4)Ga(5) is isostructural to La(10)Cl(4)Ga(5) (space group I4/mcm, No. 140) with lattice constants a = 7.9546(11) A, c = 31.793(6) A. Ln(3)ClGa(4) represents a new structural type, also in the space group I4/mcm, with a = 8.1955(8) and 8.1123(11) A, c = 11.363(2) and 11.229(2) A, respectively, for Ln = La and Ce. Ce(10)Cl(4)Ga(5) features building blocks of Ga-centered Ce(6) trigonal prisms and distinctive two-dimensional intermetallic CuAl(2) and U(3)Si(2) type nets. Its electronic structure falls within the realm of reduced rare-earth halides. Ln(3)ClGa(4) also contains the intermetallic CuAl(2) type nets, but the interstitials are inverted: The building blocks are Cl-centered Ln(6) octahedra. Its electronic structure is characterized by strong peripheral Ln-Ga bonding stabilizing the Ln(6)Cl octahedron which normally would have its Ln-Ln antibonding orbitals filled with electrons from interstitials beyond chalcogen. Magnetic susceptibility and conductivity measurements confirm the metallic nature of all three compounds. 相似文献