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91.
Oximes were oxidized to the corresponding carbonyl compounds in good to high yields by environmentally friendly and green oxidant,H_2O_2 catalyzed by montmorillonite K-10 supported cobalt(Ⅱ) chloride. 相似文献
92.
Synthesis of polyurethane/clay intercalated nanocomposites 总被引:8,自引:0,他引:8
A kind of polyurethane/organophilic montmorillonite (PU/OMT) nanocomposite based on polyether, OMT, phenylmethane diisocyante
and diglycol was synthesized and characterized by X-ray diffraction (XRD) and high-resolution electron microscopy (HREM).
A polyether/OMT hybrid was first prepared in a nanocomposite form as confirmed by XRD. It was shown that there is a multilayered
structure consisting of alternating PU chains stacked with the layers of the silicate layers in the microstructure of the
PU/OMT nanocomposite as confirmed by study of the XRD patterns and the HREM images. The contents of the hard segment of PU
and OMT had an effect on the basal spacing of the PU/OMT nanocomposite.
Received: 29 August 2000 Accepted: 16 February 2001 相似文献
93.
Naofumi Kozai Sachi Kawamura Tamotsu Kozaki Toshihiko Ohnuki Takahiro Sato Fumitaka Esaka 《Journal of solid state chemistry》2007,180(8):2279-2289
Fe2+-montmorillonite with Fe2+ ions occupying cation exchange sites is an ideal transformation product in bentonite buffer material. In our previous study on preparation and characterization of Fe2+-montmorillonite, the montmorillonite sample that adsorbed Fe2+ ions on almost all of the cation exchange sites was prepared using a FeCl2 solution under an inert gas condition [N. Kozai, Y. Adachi, S. Kawamura, K. Inada, T. Kozaki, S. Sato, H. Ohashi, T. Ohnuki, T. Banba, J. Nucl. Sci. Technol. 38 (2001) 1141]. In view of the unstable nature of iron(II) chemical species, this study attempted to determine the potential contaminant iron chemical species in the sample. Nondestructive elemental analysis revealed that a small amount of chloride ions remained dispersed throughout the clay particles. The chloride ion retention may be due to the adsorption of FeCl+ ion pairs in the initial FeCl2 solution and the subsequent containment of the Cl− ions that are dissociated from the FeCl+ ion pairs during excess salt removal treatment. Two explanations are advanced for the second process: the slow release of the remaining Cl− ions from the collapsed interlayer of the montmorillonite, and the transformation of a minor fraction of the remaining FeCl+ ion pairs to iron(III) hydroxide chloride complexes having low solubility. 相似文献
94.
Zou Hantao Yi Changhai Wang Luoxin Liu Hongtao Xu Weilin 《Journal of Thermal Analysis and Calorimetry》2009,97(3):929-935
Thermogravimetric (TG), differential thermal analysis (DTA) and thermal degradation kinetics, FTIR and X-ray diffraction (XRD)
analysis of synthesized glycine–montmorillonite (Gly–MMT) and montmorillonite bound dipeptide (Gly–Gly–MMT) along with pure
Na–MMT samples have been performed. TG analysis at the temperature range 25–250 °C showed a mass loss for pure Na–MMT, Gly–MMT
and Gly–Gly–MMT of about 8.0%, 4.0% and 2.0%, respectively. DTA curves show the endothermic reaction at 136, 211 and 678 °C
in pure Na–MMT whereas Gly–MMT shows the exothermic reaction at 322 and 404 °C and that of Gly–Gly–MMT at 371 °C. The activation
energies of the first order thermal degradation reaction were found to be 1.64 and 9.78 kJ mol−1 for Gly–MMT and Gly–Gly–MMT, respectively. FTIR analyses indicate that the intercalated compounds decomposed at the temperature
more than 250 °C in Gly–MMT and at 250 °C in Gly–Gly–MMT. 相似文献
95.
Majid M. Heravi Yahya S. Beheshtiha Mitra Ghasemzadeh Rahim Hekmatshoar Nooshin Sarmad 《Monatshefte für Chemie / Chemical Monthly》2000,131(2):187-190
Summary. Ammonium chlorochromate adsorbed on montmorillonite K-10 rapidly regenerates carbonyl compounds from their corresponding
oximes under microwave irradiation and solvent-free conditions.
Received October 11, 1999. Accepted (revised) November 15, 1999 相似文献
96.
A representative herbicide, paraquat (PQ; 1,1′-dimethyl-(4,4′-bipyridium) dichloride) was intercalated into montmorillonite by solution and solid state reaction methods. In a typical solution process paraquat aqueous solution was mixed with montmorillonite (Kunipia-F) aqueous suspension, which resulted in a paraquat-montmorillonite layer complex with a basal spacing of 1.3 nm. A paraquat-montmorillonite complex was also easily prepared by solid state reaction method. The mixture of paraquat and Na-montmorillonite was ground under ambient temperature. The basal spacing of the mixture increased to 1.3 nm after grinding for 30 min. In order to achieve the pH dependent releasing of intercalated PQ molecules, the PQ-montmorillonite complex was coated with cellulose acetate phthalate. The polymer modified PQ-montmorillonite complex exhibited a strongly suppressed PQ releasing in the acidic pH domain, while an enhanced PQ releasing at the neutral pH range, respectively. 相似文献
97.
98.
Jian-Mei Lu 《Tetrahedron》2007,63(32):7545-7549
A series of naphthalene, indene, and 6aH-benzo[c]fluorene derivatives are synthesized by intramolecular rearrangement of vinylidenecyclopropanes using a heterogeneous solid acid catalyst, montmorillonite K-10, under mild reaction conditions in good to excellent yields. The solid acidic catalyst, montmorillonite K-10, can be recovered and reused. 相似文献
99.
The poly(methyl methacrylate) (PMMA)/montmorillonite (MMT) nanocomposite was prepared by emulsifier-free emulsion technique and its structure and properties were characterized with infra red, X-ray diffraction, transmission electron microscopy, thermogravimetric analysis, and cone calorimetry. The highly exfoliated MMT layers with dimension 1-2 nm in thickness were randomly dispersed in the polymer matrix containing MMT lower than 5% w/v, whereas the intercalated structure was predominant with MMT content higher than 5% w/v. Consequently, the fine dispersion of the MMT and the strong interactions between PMMA and MMT created significant improvement of the thermo-stability and fire retardancy of the nanocomposite. The combustion behavior has been evaluated using oxygen consumption cone calorimetry. In addition, a scheme was proposed to describe fire retardancy of PMMA and MMT as well as the correlation between the interaction and structure in polymer/clay systems. The biodegradability of the nanocomposite fire-retardant was tested for its better commercialization. 相似文献
100.
Armin Weiss 《Angewandte Chemie (International ed. in English)》1981,20(10):850-860
Using layer silicates as models, the principle of replication, i.e. the spontaneous self-multiplication of a carrier of information, can be shown to be a general property of certain macromolecular systems. Errors in replication and feedback together with environmental influences may lead to mutants with higher or lower replication rates, thus enabling evolution. In the light of these findings, the question of whether or not chemical evolution resulted directly in the nucleic acid/protein system, i.e. the genetic principle common to all living systems known up to now, has to be answered. It seems conceivable that as a first step a much simpler replicating system was formed: such a system might then have undergone an evolution of replicating systems, resulting in the final nucleic acid/protein system. 相似文献