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51.
This study aimed at polymerization of methyl methacrylate with novel catalysts in the atom transfer radical polymerization (ATRP) condition at 90 °C. This was accomplished using CuBr/N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (CuBr–AEAPTMS) as a homogeneous catalyst and one time with CuBr@AEAPTMS/SBA-15 as a heterogeneous catalyst. Catalysts were characterized using TGA, FT-IR, and UV–Vis spectroscopy. The structural analysis of the polymer was carried out by 13C NMR spectroscopy and GPC. Three characteristic parts of polymer produced by ATRP method including the initiator, monomer units, and end group was shown in 13C NMR spectra. In addition, the presence of C–Br unit showed that the polymerization process is alive. The 1H NMR analysis was used for kinetic investigation of methyl methacrylate polymerization with homogeneous and heterogeneous catalysts that showed high monomer conversion (98 and 90% after 35 min, respectively) and good control of molecular weight with a dispersity (Ð = 1.5–1.7). In addition, the plot of ln ([monomer]0/[monomer] t ) versus time gave linear relationships indicating a constant concentration of the propagating species throughout the polymerization. Finally, the results of the polymerization using heterogeneous catalyst compared with homogeneous catalyst revealed that it was according to ATRP method. 相似文献
52.
Khodabakhsh Niknam Dariush Saberi Mohsen Sadegheyan Abdollah Deris 《Tetrahedron letters》2010,51(4):692-694
Silica-bonded S-sulfonic acid (SBSSA) is employed as a recyclable catalyst for the condensation reaction of aromatic aldehydes with 3-methyl-l-phenyl-5-pyrazolone. This condensation reaction was performed in ethanol under refluxing conditions giving 4,4′-alkylmethylene-bis(3-methyl-5-pyrazolones) in 75-90% yields. 相似文献
53.
54.
Ebrahim Hashemi 《Mediterranean Journal of Mathematics》2011,8(2):207-214
Let R be a ring with unity and M be a right R-module. The system M[x] forms a left near R[x]-module under addition and substitution operations. In this paper we extend the study of annihilator conditions on nearring
of polynomials to left near R[x]-module M[x], when M is a reduced Baer module. Also, we give a characterization of reduced modules. As a corollary we obtain some results of Birkenmeier
and Huang [3]. 相似文献
55.
Ahmed A. Ebrahim 《Brazilian Journal of Physics》2011,41(2-3):146-153
Angular distributions of differential cross sections for the 12C(π ±, π ±)12C and 12C(π ±, π ±)12C* reactions at pion kinetic energy ranging from 50 to 260 MeV have been analyzed with the 3α-particle model of 12C. The model provides good fits to a wide range of data. Differential cross sections for inelastic transitions to the (2?+?; 4.44 MeV) and (3???; 9.64 MeV) states in 12C are computed and the deformation lengths δ 2 and δ 3 are extracted. It is found that the extracted deformation lengths are sensitive to the nuclear model used and similar to the corresponding values found with other probes and nuclear models. 相似文献
56.
Mahmood Alaghmandan Yemon Choi Ebrahim Samei 《Journal of Mathematical Analysis and Applications》2014
Let G be a restricted direct product of finite groups {Gi}i∈I, and let Z?1(G) denote the centre of its group algebra. We show that Z?1(G) is amenable if and only if Gi is abelian for all but finitely many i , and characterize the maximal ideals of Z?1(G) which have bounded approximate identities. We also study when an algebra character of Z?1(G) belongs to c0 or ?p and provide a variety of examples. 相似文献
57.
Ebrahim Ghorbani 《Graphs and Combinatorics》2013,29(5):1377-1389
We determine all graphs whose matching polynomials have at most five distinct zeros. As a consequence, we find new families of graphs which are determined by their matching polynomials. 相似文献
58.
59.
Asadollah Zarif Farhad Amarloo Faeze Pourazimi Najmeh Kaftani Zahra Rostamabadi Ebrahim 《Journal of fluorescence》2022,32(5):1639-1650
Journal of Fluorescence - Malachite green (MG) is a dye that has been presented to use as photosensitizers for photodynamic therapy (PDT). Nonlinear absorption coefficient (β) and nonlinear... 相似文献
60.
Sarrafi Yaghoub Mehrasbi Ebrahim Mashalchi Seyyedeh Zohreh 《Research on Chemical Intermediates》2021,47(4):1729-1741
Research on Chemical Intermediates - MCM-41-SO3H, ordered mesoporous silica material MCM-41 with covalently anchored sulfonic acid groups, was used as a solid acid catalyst for the convenient,... 相似文献