排序方式: 共有97条查询结果,搜索用时 31 毫秒
61.
Masoud Nazarian-Samani Ali Reza Kamali Mahboobeh Nazarian-Samani Roohallah Mobarra Saber Naserifar 《Journal of Thermal Analysis and Calorimetry》2012,107(1):265-269
A combination of differential thermal analysis and detailed X-ray diffraction (XRD) analyses were used for the thermokinetic
study of phase evolution during heating–cooling of the mechanically alloyed (MA-ed) Ni–15 wt% B. According to the results
obtained, different phase transition sequences led to the formation of nanocrystalline Ni–B alloys comprising of Ni2B + o-Ni4B3 and Ni2B + m-Ni4B3 + B. Using the XRD studies, it was found that the Ni2B is the most stable intermetallic compound in the Ni–B binary phase diagram, and its nanocrystalline nature retained unchanged
even after annealing up to temperatures near the melting point. In addition, average enthalpy as well as activation energy
of occurred reactions was calculated; the latter was estimated using two well-known Kissinger and Augis & Bennett methods. 相似文献
62.
Masoud Nasr-Esfahani Zahra Rafiee Hassan Kashi 《Journal of the Iranian Chemical Society》2016,13(8):1449-1461
Tungstophosphoric acid nanoparticles supported on polyamic acid (TPA NPs/PAA) was prepared and employed as a catalyst for the facile selective synthesis of 1,8-dioxo-decahydroacridines and some bulky bis(1,8-dioxo-decahydroacridine)s via one-pot condensation of 5,5-dimethyl-1,3-cyclohexanedione and various aldehydes with aniline or ammonium acetate in ethanol–water solution. This catalyst was characterized by FT-IR, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), thermogravimetric analysis (TG), energy-dispersive X-ray analysis (EDAX), and inductively coupled plasma optical emission spectrometry (ICP-OES). The catalyst showed high thermal stability and good reusability. The products were isolated in high purity and the catalyst was easily separated in a simple workup and recycled several times without noticeable loss of activity under the described reaction conditions. The reaction is characterized by short reaction time, high efficiency, and mild reaction conditions. 相似文献
63.
Tahereh Ataee-Kachouei Mahboobeh Nasr-Esfahani Iraj Mohammadpoor-Baltork Valiollah Mirkhani Majid Moghadam Shahram Tangestaninejad Behrouz Notash 《应用有机金属化学》2020,34(11):e5948
In this study, a new and stable Ce(IV) immobilized on halloysite nanotube–functionalized dendrimer was designed, synthesized, and characterized using Fourier-transform infrared, elemental analysis, thermogravimetric analysis, field emission scanning electron microscopy, scanning electron microscopy–energy dispersive X-ray spectroscopy, transmission electron microscopy, dynamic light scattering, Brunauer–Emmett–Teller, and inductively coupled plasma optical emission spectroscopy techniques. This catalyst was efficiently used for the one-pot, single-step multicomponent synthesis of pyrido[3,2-c]coumarins from 4-aminocoumarin, aldehydes, and aryl ketones. The efficiency and selectivity of this catalytic system were also evaluated for the synthesis of pyrido[3,2-c]coumarins from terminal/internal alkynes instead of aryl ketones. In this respect, the regioselectivity of the products was successfully assigned by X-ray crystallographic analysis. All these reactions were best performed under solvent-free conditions in the presence of only 0.28 mol% of the catalyst, and such a one-pot multicomponent synthesis of pyrido[3,2-c]coumarins is reported for the first time. It is also worth noting that single-step and short reaction path for the synthesis of a variety of pyrido[3,2-c]coumarins along with excellent reusability of this dendritic catalyst makes this method economically and environmentally attractive. 相似文献
64.
65.
66.
67.
68.
S. Jafar Hoseini Hasan Nasrabadi Mahboobeh Azizi Alireza Salimi Beni Reza Khalifeh 《合成通讯》2013,43(12):1683-1691
Application of Fe3O4 nanoparticles (NPs) as a robust, very efficient, and magnetically recoverable catalyst was investigated in Friedel–Crafts acylation (FCA) of ferrocene and aromatic compounds. This reaction was performed with acid chlorides in solvent-free conditions at room temperature. The catalyst was easily separated by an external magnetic field from the reaction mixture. The separated catalyst was recycled for several consecutive runs without appreciable loss of its catalytic activity. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file. 相似文献
69.
A regioselective and convenient procedure for preparation of amines by reductive amination of aldehydes and ketones using sodium borohydride in the presence of sulfuric acid supported on silica gel as an active, inexpensive, and recoverable catalyst under heterogeneous and solvent-free conditions at room temperature is described. 相似文献
70.
A wide range of mono‐ and disubstituted dihydroquinazolinones were synthesised via condensation of isatoic anhydride, primary amines, or ammonium salts with aromatic aldehydes in the presence of montmorillonite K‐10. The catalyst is reusable and could be recycled for several runs without any decrease in its efficiency. 相似文献