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51.
Friedel–Crafts acylation reaction between polystyrene and phthalic anhydride in the presence of AlCl3 has been performed in two different solvents, 1,2-dichloro ethane and nitro-benzene. The morphology of the condensate prepared in 1,2-dichloroethane has revealed the participation of 1,2-dichloroethane, i.e., a competitive Friedel–Crafts alkylation reaction. 相似文献
52.
53.
Effect of side‐chain functionality on the organic field‐effect transistor performance of oligo(p‐phenylenevinylene) derivatives 下载免费PDF全文
In order to observe the effects of the substitution of electronegative flourine with aromatic groups in oligo(p ‐phenylenevinylene) compounds on their packing, morphology, and charge carrier mobility, we have synthesized napthol‐substituted oligo(p ‐phenylenevinylene) compounds and examined their solubility, redox properties, thin film morphologies, and charge carrier properties. To date, very few examples of conjugated oligomers bearing napthol side groups have been reported in the literature. After annealing at 150 °C, the mobility of S1, S2, and S3 was 4.0 × 10?2 cm2 V?1 s?1, 1.2 × 10?2 cm2 V?1 s?1, and 2.6 × 10?3 cm2 V?1 s?1, respectively. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44825. 相似文献
54.
Poly(ester amides) based on L-valine and adipic acid with different aliphatic and aromatic diols were synthesized by interfacial polymerization. Four different diols such as ethylene glycol, 1,5-pentanediol, resorcinol, and catechol were used to systematically vary the chain lengths and position of the hydroxyl groups. The chemical structures, thermal properties, degradation, and dye release of these polymers were investigated. This study demonstrates that the release kinetics can be tailored through the control of the chain length of the diol and the position of the hydroxyl groups. These findings have important implications for designing biodegradable polymers for tailored release. 相似文献
55.
Prof. Dr. Sakuntala Chatterjee Dr. Ramanna Harish Prof. Dr. Gunter M. Schütz 《化学,工程师,技术》2013,85(11):1671-1679
In the past, the investigation of catalytic reactivity enhancement through molecular traffic control (MTC) by means of dynamical Monte Carlo simulations of catalysis was initiated in simple, idealized zeolite channel networks. These results are reviewed here and, emphasizing more recent work, the conditions of reactivity enhancement through MTC are examined for a realistic channel topology based on the pore structure of the zeolite TNU‐9. For a wide range of reaction rates a very strong MTC effect can be found that increases with grain size. This effect is argued to be a generic feature of a certain class of zeolite pore topologies. 相似文献
56.
In this work we demonstrate a large electric field‐induced bipolar strain ~0.40% in Li, Ta and Sb modified BNT–KNN ((1?x) Bi0.5Na0.5TiO3–xK0.47Na0.47Li0.06 Nb0.74Sb0.06Ta0.2O3) system. The morphotropic phase boundary (MPB) of the system between rhombohedral and tetragonal phases lies in the range 0.02 ≤ x ≤ 0.06, beyond which all compositions (up to x < 0.15) were found to be tetragonal. A clear trade‐off between the large strain values and achievable d33, kp for a particular composition was noted. It is shown that while for x = 0.03, d33 169 pC/N, kp 49% and strain ~0.13% were obtained, for x = 0.08 with 0.40% strain, d33 and kp values decreased drastically. 相似文献
57.
The coalescence-redispersion (CRD) model is examined in the fast chemistry limit for the single bimolecular reaction A+B M R and the series parallel reactions A+B M R;B+R M S occurring in a plug flow reactor with unmixed feed streams. For the single bimolecular reaction it is shown that in this limit the CRD model is asymptotically equivalent to the 3E fast closure as t M 0. For the series parallel reactions the CRD model predictions tend to be bracketed by the 3E slow and fast closure formulations. Representative results are presented for the variance decay of the individual reactants, and it is seen that even in the fast reaction limit where mixing is controlling, the shape of the feed stream PDFs has negligible influence on the progress of the reaction. 相似文献
58.
Indranil Chatterjee David Bastida Paolo Melchiorre 《Advanced Synthesis \u0026amp; Catalysis》2013,355(16):3124-3130
We report a triple vinylogous cascade reaction, yielding valuable spiro‐oxindolic cyclohexane derivatives. The three‐component domino process proceeds by way of a catalyzed Michael/1,6‐addition/vinylogous aldol sequence affording the products with six stereogenic centers and very high control over the stereochemistry. The chemistry is based on a rare example of asymmetric 1,6‐addition to linear 2,4‐dienals proceeding with complete δ‐site selectivity. Key to the reaction development was a directing group positioned at the β‐dienal position, which was essential for achieving highly predictable reaction outcomes.
59.
Uma Chatterjee 《Polymer》2005,46(5):1575-1582
ATRP of several methacrylates viz. methyl methacrylate (MMA), ethyl methacrylate (EMA), n-butyl methacrylate (nBMA), t-butyl methacrylate (tBMA), benzyl methacrylate (BzMA) and (N,N-dimethylamino)ethyl methacrylate (DMAEMA) has been studied in neat as well as aqueous (up to 12 vol% water) acetone at 35 °C using CuCl/bipyridine (bpy) catalyst and ethyl 2-bromoisobutyrate as the initiator. Addition of water significantly enhances the rate of polymerization without losing control. Unlike CuCl/bpy the CuBr/bpy catalyst gives poor control which is attributed to the lower solubility and consequent heterogeneity in the latter case. Of the other ligands used with the CuCl catalyst viz. o-phenanthroline (o-phen), 1,1,4,7,7-pentamethyldiethylenetriamine (PMDETA), 1,1,4,7,10,10-hexamethyltriethylenetetramine (HMTETA), Me6TREN only o-phen offers reasonably good control. The CuCl/bpy catalyst system has been used also in preparing some di- and tri-block copolymers with reasonably low polydispersity index (PDI) at ambient temperature (35 °C) using aqueous acetone as the solvent. The following block copolymers have been prepared PMMA-tBMA, PMMA-b-tBMA-b-MMA, PMMA-DMAEMA, by this method. 相似文献
60.
Silicon - Titanium Nitride (TiN) thin films were deposited by thermal chemical vapor deposition process (CVD) over Si (100) substrate under different substrate temperatures. Morphological,... 相似文献