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本文以过氧化二碳酸酯BPPD和芳叔胺DHET、DHPT、DMT、DMA组成的引发体系进行MMA聚合的研究。测定了聚合速率Rp,发现添加DHET、DHPT能促进MMA的聚合,缩短诱导期,提高Rp,其效果要比DMT、DMA为好。测定了E3和聚合速率方程。由ESR谱和端基分析证实DHET、DHPT芳胺组分产生的自由基能引发单体聚合。 相似文献
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芳香叔胺引发丙烯腈光聚合的引发机理 总被引:1,自引:0,他引:1
芳香叔胺引发丙烯腈(AN)光聚合是通过形成激基复合物(exciPlex)进行的。紫外光谱和荧光光谱表明,芳香叔胺在基态可以和AN形成电荷转移复合物(CTC),而在激发态可和AN形成exciplc(称定域激发)。CTC经光照亦可激发(称CTC激发)。 定域激发引起光聚合速率为CH_3C_6H_4N(CH_3)_2>C_6H_5N(CH_3)_2>HOCH_2·C_6H_4N(CH_3)_2>CH_3C_6H_4N(CH_2CH_2OH)_2,与芳胺荧光被AN淬灭的Stern-Vo-lmer常数顺序一致。CTC激发引起的光聚合顺序为:CH_3C_6H_4N(CH_3)_2>CH_3C_6H_4N(CH_2CH_2OH)_2>HOCH_2C_6H_4N(CH_3)_2>C_6H_5N(CH_3)_2,与芳胺上取代基推电子能力一致。端基分析表明聚合物有芳胺端基。 相似文献
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核磁、离子色谱等测试方法证明 ,以烯丙基型卤代烷烃为引发剂引发的过渡金属催化的活性自由基聚合 ,所得聚合物的端基为卤素[13].由于C—X(X =Cl,Br)键容易断裂 ,因此卤素端基的存在会影响聚合产物的热稳定性 .但由于C—X键易于进行各种反应 ,含卤素端基的聚合物可以作为大分子引发剂用于引发其它合适单体反应 ,从而使卤素端基转化为其它基团 ,或合成新型结构的共聚物 .环状单体 2 甲基 2 唑啉 (Me OXZ)亲核性较强 ,可以直接由烯丙基型卤代物引发剂引发活性开环聚合[4 6 ],因此可望以含卤端基的活性聚合产物作为Me OX… 相似文献
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多肽是由α-氨基酸以肽键形式连接在一起而形成的天然聚合物,具有多种重要生物功能。α-氨基酸N-羧基环内酸酐(NCA)开环聚合是制备多肽聚合物最便捷的方法,被多个领域广泛应用。传统的NCA聚合对水分非常敏感,通常使用严格干燥溶剂并在手套箱中操作;NCA聚合反应速率一般很慢,而且NCA单体本身不稳定,长时间的聚合会导致副反应的产生,并难以获得高分子量多肽聚合物。这些长期未解决的难点阻碍了NCA聚合材料的发展。最近,华东理工大学刘润辉课题组报道了六甲基二硅基胺基锂(LiHMDS)引发的NCA开环聚合方法,此方法聚合速率快,对水分不敏感,可在敞口容器中聚合,摆脱了对手套箱的依赖;该NCA聚合可合成高分子量多肽聚合物,产物具有多肽特征性的二级结构;另外,LiHMDS引发的NCA开环聚合为活性聚合,可实现多肽聚合物的端基功能化。 相似文献
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Marc Eberhardt 《European Polymer Journal》2005,41(7):1569-1575
Pentafluorophenyl acrylate and -methacrylate were polymerized using AIBN as a thermal initiator. The obtained polymers were soluble polymeric active esters that could be used for the preparation of multifunctional polymers. The reactivity of poly(pentafluorophenylacrylate) and poly(pentafluorophenylmethacrylate) towards primary and secondary amines, as well as alcohols was investigated in a quantitative way. Both poly(active esters) reacted satisfactorily with aliphatic primary and secondary amines but only low conversion was found in the case of aromatic amines. Conversions of only 30% were reached when poly(pentafluorophenylacrylate) was treated with one equivalent of alcohol under base catalysis. In time resolved FT-IR studies the rate constants of the polymer analogous reactions were determined. 相似文献
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Ding Wang Ye Liu Chun‐Yan Hong Cai‐Yuan Pan 《Journal of polymer science. Part A, Polymer chemistry》2005,43(21):5127-5137
Novel hyperbranched poly(amido amine)s containing tertiary amines in the backbones and acryl as terminal groups were synthesized via the Michael addition polymerizations of trifunctional amines with twofold molar diacrylamide. The hyperbranched structures of these poly(amido amine)s were verified by 13C NMR (INVGATE). The polymerization mechanisms were clarified by following the polymerization process with NMR method, and the results show that the reactivity of secondary amine formed in situ is much lower than that of the secondary amine in 1‐(2‐aminoethyl) piperazine (AEPZ) ring and the primary amine. The secondary amine formed in situ was almost kept out of the reaction before the primary and secondary amines in AEPZ were consumed, leading to the formation of the AB2 intermediate, and the further reaction of the AB2 yielded the hyperbranched polymers. The molecular weights and properties of poly(amindo amine)s obtained were characterized by GPC, DSC, and TGA, respectively. Based on the reaction of active acryl groups in the polymers obtained with glucosamine, hyperbranched polymers containing sugar were formed. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5127–5137, 2005 相似文献
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LU Wen-chao XI Chan-juan Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology Ministry of Education 《高等学校化学研究》2009,25(5):638-643
The oxidative coupling of primary aromatic amines was investigated. Ce(SO4)2 can mediate the oxidative coupling of primary aromatic amines in water to dimers, trimers and/or tetramers, which depended on the substituents of primary aromatic amines. When 2,6-dimethylaniline or 2,6-diethylaniline was used as substrate, dimer, and tetramer were formed as major products. When 2,6-diisopropylaniline or 2,6-dihaloanilines was used as substrate, dimer, and trimer were formed. The mechanistic aspect was also investi... 相似文献
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Ding Wang Zhiju Zheng Chunyan Hong Ye Liu Caiyuan Pan 《Journal of polymer science. Part A, Polymer chemistry》2006,44(21):6226-6242
Novel hyperbranched poly(amido amine)s containing tertiary amines on the backbones and acryl or secondary amines as the surface groups were successfully synthesized via the Michael addition polymerizations of a triacrylamide [1,3,5‐triacryloylhexahydro‐1,3,5‐triazine (TT)] and a difunctional amine [n‐butylamine (BA)] NMR techniques were used to clarify the structures of hyperbranched polymers and polymerization mechanism. The reactivity of the secondary amine formed in situ was much lower than that of the primary amines in BA. When the feed molar ratio was 1:1 TT/BA, the secondary amine formed in situ was almost kept out of the reaction before the BA (AA′) and TT (B3) monomers were consumed, and this led to the formation of A′B2 intermediates containing one secondary amine group and two acryl groups. The self‐polymerization of the A′B2 intermediates produced hyperbranched polymers bearing acryl as surface groups. For the polymerization with the feed molar ratio of 1:2 TT/BA, A′2B intermediates containing one acryl group and two secondary amine groups were accumulated until self‐polymerization started; the self‐polymerization of the intermediates formed hyperbranched polymers with secondary amines as their surface groups. Modifications of surface functional groups were studied to form new hyperbranched polymers. The hyperbranched poly(amido amine)s were amorphous. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6226–6242, 2006 相似文献
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Selective N-alkylation of amines using nitriles under hydrogenation conditions: facile synthesis of secondary and tertiary amines 总被引:1,自引:0,他引:1
Ikawa T Fujita Y Mizusaki T Betsuin S Takamatsu H Maegawa T Monguchi Y Sajiki H 《Organic & biomolecular chemistry》2012,10(2):293-304
Nitriles were found to be highly effective alkylating reagents for the selective N-alkylation of amines under catalytic hydrogenation conditions. For the aromatic primary amines, the corresponding secondary amines were selectively obtained under Pd/C-catalyzed hydrogenation conditions. Although the use of electron poor aromatic amines or bulky nitriles showed a lower reactivity toward the reductive alkylation, the addition of NH(4)OAc enhanced the reactivity to give secondary aromatic amines in good to excellent yields. Under the same reaction conditions, aromatic nitro compounds instead of the aromatic primary amines could be directly transformed into secondary amines via a domino reaction involving the one-pot hydrogenation of the nitro group and the reductive alkylation of the amines. While aliphatic amines were effectively converted to the corresponding tertiary amines under Pd/C-catalyzed conditions, Rh/C was a highly effective catalyst for the N-monoalkylation of aliphatic primary amines without over-alkylation to the tertiary amines. Furthermore, the combination of the Rh/C-catalyzed N-monoalkylation of the aliphatic primary amines and additional Pd/C-catalyzed alkylation of the resulting secondary aliphatic amines could selectively prepare aliphatic tertiary amines possessing three different alkyl groups. According to the mechanistic studies, it seems reasonable to conclude that nitriles were reduced to aldimines before the nucleophilic attack of the amine during the first step of the reaction. 相似文献
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Choukourov A Biederman H Slavinska D Hanley L Grinevich A Boldyryeva H Mackova A 《The journal of physical chemistry. B》2005,109(48):23086-23095
Plasma polymerization of allylamine is performed both in continuous wave and pulsed mode. Chemical derivatization is applied to determine primary and secondary amine concentration. Primary amines are efficiently formed, but secondary amines are more abundant. A polymerization mechanism is proposed to account for the difference in amine content obtained from comparison between continuous wave and pulsed mode plasma polymerization. The AFM measurements performed on ultrathin (1-10 nm) plasma polymers confirm the continuity of films and that the film growth on silicon occurs via a layer-by-layer mechanism because no islandlike structures were detected. 相似文献
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[Structure: see text] Catalyst-free N-tert-butyloxycarbonylation of amines in water is reported. The N-t-Boc derivatives were formed chemoselectively without any isocyanate, urea, N,N-di-t-Boc, and O/S-t-Boc as side products. Chiral amines, esters of alpha-amino acids, and beta-amino alcohol afforded optically pure N-t-Boc derivatives. Amino alcohol and 2-aminophenol afforded the N-t-Boc derivative without oxazolidinone formation. Selectivity was observed during competition of aromatic amine vs aliphatic amine, amine vs amino acid ester, amine vs amino alcohol, and primary amine vs secondary amine. 相似文献
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A series of arylamino- and alkylamino-substituted diphenylporphyrins and tetraphenylporphyrins were efficiently synthesized by reactions of brominated porphyrin precursors with amines via palladium-catalyzed amination. The multiple amination reactions are general and suitable for a variety of amines, affording the desired aminoporphyrins in good to excellent yields. Examples include aromatic and aliphatic amines, primary and secondary amines, electron-rich, -neutral, and -poor amines as well as heteroaromatic amines and imines. 相似文献
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W. Bracke 《Journal of polymer science. Part A, Polymer chemistry》1972,10(4):975-981
The reactions of polydiethynylbenzene with hydrogen sulfide or primary amines are described. The properties of the resulting fully aromatic polymers are reported. 相似文献
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The reaction of N-polyfluorophenylcarbonimidoyl dichlorides with primary and secondary aliphatic and aromatic amines have been studied. With primary aliphatic amines, the reactions led to carbodiimides or guanidines, depending on the amount of amine. The carbodiimides obtained reacted with amines to form guanidines. The reactions with primary aromatic amines produced only triarylguanidines. N-Pentafluorophenyllcarbonimidoyl dichloride (I) reacted with tetrafluoro-o-phenylene diamine to give 2-pentafluoroanilino-4,5,6,7-tetrafluorobenzimidazole. Polyfluorinated benzimidazole derivatives were also produced by the thermolysis of polyfluorinated triarylguanidines. Heating of N1,N2,N3-tris(pentafluorophenyl)guanidine with K2CO3 in dimethylformamide led to 1,2,3,4,7,8,9,10-octafluoro-5-pentafluorophenyl-5H-benzimidazol[1,2-a]benzimidazole. N-Polyfluorophenylcarbonimidoyl dichlorides reacted with various secondary amines already at room temperature giving N-polyfluorophenylchloroformamidines in high yields. Elevated temperature and prolonged reaction time led to formation of N-polyfluorophenylguanidines. Kinetics and mechanism of the reactions of N-polyfluorophenylcarbonimidoyl dichlorides with primary and secondary amines in acetonitrile at 25°C have been studied. The reactions have been found to proceed by a bimolecular nucleophilic addition-elimination mechanism via a tetrahedral intermediate. Possible reasons of formation of different products in the above transformation are discussed in terms of this mechanism. 相似文献