Papers by Keyword: Cyclohexene

Abstract: The paper presents the results of studies of the reaction of the interaction of phenol with cyclohexene (CH) in the presence of a Zeolite-Y catalyst impregnated with phosphoric acid and studying the dependence on the yield and selectivity of the target product on various parameters. As a result of the study of the phenol cycloalkylation by cyclohexene, optimal conditions were found, the yield of which is 81.6 % of theory for the taken CH, and the selectivity is 94.0 % for the target product. The developed mathematical model of the processes of the interaction of phenol with cyclohexene in the form of a regression polynomial made it possible to find the optimal values ​​of the input variables.

Abstract: A tungsten-containing mesoporous molecular sieve SBA-15 (W-SBA-15) was synthesized directly by the hydrolysis of tetraethylorthosilicate and ammonium tungstate with triblock copolymer EO₂₀PO₇₀EO₂₀ (P123) as template in acidic medium. The W-SBA-15 was characterized by XRD, N₂ adsorption/desorption, UV-Vis spectroscopy, Raman spectroscopy and ICP-AES spectrometry. The W-SBA-15 exhibited high catalytic activity for the hydroxylation of cyclohexene with hydrogen peroxide (H₂O₂) as oxidant. The complete conversion of cyclohexene into glycol monoethers with very high selectivity (92.6%) were obtained over the W-SBA-15 catalyst.

Abstract: Mesoporous silica pillared clay (SPC) materials with different contents of H₄PMo₁₁VO₄₀ (PVMo) heteropoly acid were synthesized by introducingPVMo into clay interlayer template in an acidic suspension using sol–gel method. The results of the characterizations showed that PVMo was dispersed homogeneously in the encapsulated samples. The encapsulated materials exhibited good catalytic performance in oxidation of cyclohexene.

Abstract: In order to establish quantitative structure-activity relationship (QSAR) model of cyclohexene derivatives as neuraminidase inhibitors, the relationships between the anti-influenza activity of 34 cyclohexene derivatives and their molecular connectivity indices (^mX) as well as their electrotopological state indices (I_m) were analyzed, meanwhile molecular structures of the substances were also effectively characterized. On the one hand, two molecular connectivity ⁰X, ³X and four electrotopological state indices I₁, I₃, I₆, I₁₆, which were obtained by optimization of multiple linear stepwise regression, were employed to found QSAR model through stepwise regression analysis, where the correlation coefficient of equation was 0.906 and the average absolute error between experimental values and estimates was 0.37. On the other hand, Using these structural parameters above as the input neurons, a satisfying neural network model with the 6-2-1 network architecture was also constructed by the back-propagation (BP) algorithm, where the total correlation coefficient reached up to 0.966 and the average absolute error between experimental values and estimates of the model decreased to 0.19. Therefore it was concluded that the results of BP network were better than those of multiple linear regression methods.

Abstract: Monometallic gold and bimetallic gold-iron catalysts supported on alumina were prepared in order to check their activity and selectivity in the reaction of cyclohexene oxidation. Au/Al₂O₃ was prepared by a deposition precipitation with urea (DPU) method, while the bimetallic catalyst Au-Fe/Al₂O₃ was prepared by under potential deposition (UPD). The characterization by ICP and EDS showed that very small amount of iron are deposited near gold nanoparticles. However, TEM images showed that the deposition method of iron induced gold nanoparticles sintering. All catalysts were tested in the reaction of cyclohexene oxidation in order to check the influence of both the size of gold particles and the presence of iron on the catalytic activity and selectivity. Small gold nanoparticles were shown be efficient in cyclohexene oxidation where the presence of iron influenced widely the selectivity towards the formation of cyclohexene oxide.

Abstract: A series of supported Cu2O catalysts on Mg(OH)2 or γ-Al2O3 were prepared by coprecipitation-chemical reduction combined with impregnation using Cu(NO3)2 as precursor salt and hydrazine hydrate as the reducing agent. The crystal phase characteristics and specific suface area of the samples have been characterized by means of X-ray powder diffraction (XRD) and BET method. Catalytic dehydrogenation reaction activity of cyclohexanol over the catalysts was investigated. Results showed Cu2O is the main active component over the supported catalysts. Cu2O Grain has good dispersion in nanoscale. Acid or alkali type of the support has great influence on cyclohexanol dehydrogenation activity of supported Cu2O catalysts. There have cyclohaxene and cyclohexanone products over the supported catalysts. The reaction activity of Cu2O/ Mg(OH)2 catalysts changed with hydrazine hydrate volume. Cyclohexanol conversion and cyclohexanone selectivity can reach to 97.2% and 71.2%.

Abstract: W-SBA-15 mesoporous material was synthesized by using a one-step co-condensation sol-gel process and characterized by various methods. The results showed that the prepared W-SBA-15 sample retained the typical mesoporous structure of SBA-15 and exhibited good catalytic performance for the green synthesis of adipic acid under organic solvent-free conditions.

Abstract: Ti-SBA-15 mesoporous materials with different Si/Ti molar ratios were synthesized via a hydrothermal process and characterized by using various techniques. The effect of Si/Ti molar ratios in the gels on the structure and catalytic efficiency in epoxidation of cyclohexene was discussed in details. The results showed that all the Ti-SBA-15 materials retained SBA-15 mesoporous structure and exhibited good catalytic activity. Furthermore,the sample prepared with Si/Ti =50 exhibited the best catalytic performance under the reaction conditions.

Abstract: Oxidative dehydrogenation of cyclohexane was studied over three pure Mg-V-O catalysts, which are Mg₃(VO₄)₂, Mg₂V₂O₇ and MgV₂O₆, respectively. Catalysts were prepared via citric acid complexation and characterized by N₂-adsorption, XRD, FT-IR, NH₃-TPD and H₂-TPR techniques. Among the pure magnesium vanadates, Mg₃(VO₄)₂ has the isolated active sites, weakly basic surface and lower reducibility of the metal cations, and could be recognized as the catalytic active phase. Mg₃(VO₄)₂ catalyst exhibited a better catalytic performance, on which a cyclohexene selectivity of 41.5% at cyclohexane conversion of 15.5% was obtained.

Abstract: Ti-SBA-15 mesoporous materials were directly synthesized via a hydrothermal process and characterized by using nitrogen adsorption-desorption measurements, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, diffuse reflectance ultraviolet-visible spectroscopy, and infrared ray spectroscopy. The effect of synthesis temperatures on the structure and catalytic efficiency in epoxidation of cyclohexene was discussed in details. The results showed that the optimal temperature was 100 °C under the reaction conditions.