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1.
Abstract 2-Hydroxy-4-acryloxyacetophenone (HAAP) was synthesized and polymerized in 2-butanone using benzoyl peroxide as initiator at 65 °CC. Poly(2-hydroxy-4-acryloxyacetophenone-semicarbazone) (HAAPS) was prepared from poly(HAAP) and semicarbazide hydrochloride and was characterized by IR and NMR spectral studies. The molecular weights of the polymer was determined by gel permeation chromatography. Cu(II) and Ni(II) chelates of poly(HAAPS) were synthesized. Thermogravimetric analysis of the polychelates have been carried out. Elemental analysis of the poly chelates suggest a metal to ligand ratio as 1:2. The polychelates were also characterized by infrared, electronic spectral studies, magnetic, and conductivity measurements. 相似文献
2.
Fu-Mian Li Qing-Yu Gao Lin Wang Ju-Xian Zhang Shuang-Ji Chen Zi-Chen Li 《Journal of polymer science. Part A, Polymer chemistry》1997,35(6):1087-1093
Acrylic monomers bearing electron-donating quinolyl moiety, i.e., 8-acryloyloxyquinoline (AQ) was prepared and polymerized. It was found that the fluorescence intensity of AQ was much lower than that of P(AQ) at the same chromophore concentration. The fluorescence of P(AQ) could be quenched by electron-deficient vinyl monomers, such as acrylonitrile (AN) and methyl methacrylate (MMA). This is another example of the “fluorescence structural self-quenching effect” termed by us previously, and demonstrates again that this phenomenon is not an accidental but a general one for acrylic monomers bearing electron-donating chromophores. The photopolymerization of acrylonitrile (AN) sensitized by AQ and P(AQ) as well as combining with carbon tetrabromide (CBr4) was studied kinetically. From the rates of the polymerization (Rp) and overall activation energies obtained for these four systems, it was found that Rp sensitized by the binary systems was much higher than by AQ or P(AQ) alone, while the molecular weights of the resulting P(AN) were lower. The fluorescent analysis of the resulting P(AN) in solution showed that the sensitizers also entered into the P(AN) chains. A mechanism of charge transfer complex (CTC) formation was tentatively suggested for the photopolymerization of AN initiated by these four systems. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 1087–1093, 1997 相似文献
3.
《Journal of Coordination Chemistry》2012,65(4):283-298
Two novel asymmetrical Schiff-base ligands, H2L1 and H2L2, were prepared by reacting two half-unit Schiff-base compounds with 2-methyl-7-formyl-8-hydroxyquinoline. The two half-unit Schiff-base compounds were initially prepared by condensing dimedone with either ethylenediamine or p-phenylenediamine, respectively. Both ligands are dibasic and contain two sets of NO coordinating sites. Twelve metal complexes were obtained by reacting both ligands with Cu(II), Ni(II), Co(II), Mn(II), Fe(III), VO(IV) cations. The ligands and their metal complexes were characterized by elemental analysis, IR, UV-Vis, ESR and mass spectra, also magnetic moments of the complexes were determined. Visible spectra of the complexes indicated distorted octahedral geometries around the metal cations. ESR spectra indicated mononuclear and dinuclear structures of the complexes of ligands H2L1 and H2L2, respectively. Magnetic moments of the complexes were rather low compared with those expected for octahedral geometries and indicated polymeric linkage of the metal complex molecules within their crystal lattices. The insolubility of the metal complexes in most organic solvents support the polymeric structures. 相似文献
4.
以三乙基铝 (TEA) 为保护剂, 研究了 TiCl4/MgCl2/芴二醚/Al(C2H5)3 体系催化丙烯与十一烯醇或十一烯酸的共聚反应. 结果表明, 在极性单体存在下, 聚合反应活性随极性单体加入量的增加而降低, 但可保持丙烯均聚活性的一半以上, 反应活性衰减较小. 同时, 随着极性单体加入量的增加, 极性单体在共聚物中的含量增加. 与十一烯酸相比, 十一烯醇共聚具有更高的共聚活性和共单体含量. 随着共聚物中极性单体含量的增加, 聚合物的熔点和结晶温度都有所降低. 反应温度对丙烯和十一烯醇共聚的反应活性和共单体含量影响较小. 相似文献
5.
铝卟啉是一类土壤环境友好的金属卟啉,尽管早在1978年Inoue就已经发现它可以催化CO2和环氧丙烷的共聚反应,但是该催化体系一直面临催化活性低、聚合物相对分子质量低等难题。 本文通过改变铝卟啉催化剂配体中苯环上取代基的种类和位置,制备出中心金属电子环境差异化的铝卟啉,并以双三苯基膦氯化铵(PPNCl)为助催化剂,探讨其对CO2与环氧丙烷的共聚反应的催化行为。 结果表明,当铝卟啉中苯环上2,4位同时被Cl-取代后,在90 ℃和3 MPa压力下,转化频率(TOF)达到2672 h-1。 当利用离去能力较强的对甲苯磺酸基团(OTs-)作为铝卟啉的轴向配体,可以合成出数均相对分子质量达1.84×105的脂肪族聚碳酸酯。 相似文献
6.
Mikhail A. Matsko Ludmila G. Echevskaya Vladimir A. Zakharov Marina I. Nikolaeva Tatyana B. Mikenas Marina P. Vanina 《Macromolecular Symposia》2009,282(1):157-166
Summary: Heterogeneity of active centers (AC) of titanium-magnesium catalysts (TMC) and vanadium-magnesium catalyst (VMC) in ethylene-hexene-1 copolymerization has been studied on the base of data of polymer molecular weight distribution (MWD) deconvolution technique and copolymer fractionation onto narrow fractions. It was found that 3 and 4 Flory components (groups of active centers) are required to describe experimental MWD curves of copolymers produced over TMC with different Ti content. In the case of VMC MWD of homopolymer and copolymer are characterized by set of 5 Flory components (5 groups of AC). Different character of inter-relationship between MW and short chain branching (SCB) was found for ethylene-hexene-1 copolymers produced over different catalysts: heterogeneous type in the case of TMC and more uniform for copolymer prepared over VMC. The content of Ti affects on the slope of that profile in copolymers produced over TMC. The results indicated that TMC and VMC are different greatly on the heterogeneity of active centers to the formation of polymers with different molecular weights and to formation of copolymers with different inter-relationship between MW and short chain branching. TMC produces polymers with more narrow MWD but it contains highly heterogeneous centers regarding comonomer reactivity ratios. VMC produces polymers with broad and bimodal MWD but it contains more homogeneous centers regarding comonomer reactivity ratios. 相似文献
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I. M. Abd-Ellah B. A. El-Sayed M. A. El-Nawawy A. M. A. Alaghaz 《Phosphorus, sulfur, and silicon and the related elements》2013,188(12):2895-2906
Co(II), Ni(II), and Cu(II) form 2:1 complexes with aminocyclodiphosph(V)azane derivative. The complexes have been investigated in solution by the spectrophometric molar ratio and conductometeric methods. The ligand and its complexes have been isolated in solid state and characterized on the basis of microanalytical, infrared, electronic, magnetic moment, 1 H NMR and mass spectral data. The cobalt and nickel complexes were assigned to be in tetrahedral structure while the copper complex is assigned to be in square planar. 相似文献
9.
A template synthesis procedure yielded [Ni(HL1)NH3]I, where HL1 is the monoanion of the terdentate ONN benzoylacetone S-methylisothiosemicarbazone ligand. The reaction of this complex with an excess of NH4NCS, pyridine, or hydrazine resulted in the complexes [Ni(HL1)(NH3)NCS] and [Ni(L1)A] (A = Py, N2H4). The monoanionic form of the ligand is obtained by deprotonation of the enolic form of the benzoylacetone moiety, whereas the dianion is formed by additional deprotonation of the terminal NH2 group. Finally, the reaction of [Ni(HL1)NH3]I with salicyladehyde produced the NiL2 complex in which L2 stands for the dianion of the ONNO ligand N(1)-2-butylidene-4-oxo-4-phenyl-N(4)-salicylidene-S-methylisothiosemicarbazide. All complexes are diamagnetic and have a square-planar configuration, except for [Ni(HL1)(NH3)NCS], for which te data of i.r. spectra suggest a square-pyramidal structure. The electronic absorption spectra of the ethanolic solutions of all complexes are characteristic of typical square-planar coordination of nickel(II). 相似文献
10.
Adel A. A. Emara 《Phosphorus, sulfur, and silicon and the related elements》2013,188(5):1201-1211
New mixed ligand Cr(III) complexes were prepared where diamine or oxalato ligands are coordinated together with either tellurito, selenito, or hydrogenselenito ions to form nine octahedral complexes. The complexes were characterized by chemical analyses, IR and UV-visible spectra, magnetic, and conductivity measurements. The tellurito and selenito ligands act as monodentate ligands, coupled with the bidentate diamine ligands. On the other hand, they act as bidentate chelate ligands when coordinated together with the oxalate ligand. However, hydrogenselenite ion act as a monodentate ligand coupled with the oxalate ligand. IR spectra indicated that the inorganic ligands are coordinated to the Cr(III) ion through their oxygen atoms. One of the bulky diamine molecules, 1,2-pn or 1,3-pn, was freed from the coordination sphere of Cr(III) on the addition of the bulky inorganic anions and was replaced by two water molecules. 相似文献
11.
Munir Ullah Khan Safir Ullah Khan Xiaohan Cao Muhammad Usman Xinchen Yue Abdul Ghaffar Muhammad Hassan Prof. Chengjian Zhang Prof. Xinghong Zhang 《化学:亚洲杂志》2023,18(1):e202201050
This study demonstrates the superiority of a stable and well-defined heterogeneous cobalt hexacyanocobaltate (Co3[Co(CN)6]2), a typical cobalt Prussian Blue Analogue (CoCo-PBA) that catalyzes the copolymerization of carbonyl sulfide (COS) and propylene oxide (PO) to produce poly(propylene monothiocarbonate)s (PPMTC). The number-average molecular weights of the PPMTC were 66.4 to 139.4 kg/mol, with a polydispersity of 2.0–3.9. The catalyst productivity reached 1040 g polymer/g catalyst (12.0 h). The oxygen-sulfur exchange reaction (O/S ER), which would generate random thiocarbonate and carbonate units, was effectively suppressed, and thus the selectivity of the monothiocarbonate over carbonate linkages was up to >99%. It was shown that no cyclic thiocarbonate byproduct was produced during the heterogeneous catalysis of COS/PO copolymerization using CoCo-PBA as the catalyst. The content of monothiocarbonate and ether units in the copolymer chain could be regulated by tuning the feeding amount of COS. 相似文献
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Rate constants (k1 k11, k12, k22, k21 and kt) for various steps involved in the copolymerization of propylene oxide (PO) with tetrahydrofuran (THF) have been calculated from reaction rate data obtained with the following catalyst system: (a) triphenyl-methyl cations ((C6H5)3C+) associated with hexafluorophosphate (PF6 ?), hexafluoroarsenate (AsF6 ?) and hexafluoroantimonate (SbF6 ?) gegenions; (b) antimony pentachloride (SbCl5); and, (c) boron trifluoride etherate, BF3:(C2H5)2O. The latter two systems were studied in the presence of cocatalysts. The effects of several parameters (the cocatalyst concentration and bulk size, the nature of the solvent, and the reaction temperature) on the rate constants are highlighted. The role of entropy in the initiation, propagation and termination steps is discussed in terms of solvation and desolvation processes. Based on termination activation energy considerations, the order of stability for the gegenions used in the copolymerization of PO with THF was found to be: AsF6 ? > SbF6 ? > HOBF3 ?PF6 ? > SbCl6 ? 相似文献
14.
采用量子化学MNDO和CNDO/2-CO计算方法,对聚偶氮乙烯(C2H2N2)23种异构体的稳定性进行了比较,指出聚偶氮乙烯和聚异亚甲基亚胺分子的稳定性比聚亚甲基亚胺高,分析了造成稳定性差异的原因。能带结构计算表明:三者中聚异亚甲基亚胺的导电性能最好,可望具有较高的本征和掺杂电导率。 相似文献
15.
报道了稀土配位催化剂对环硫氯丙烷(CMT)与环氧丙烷(PO)的共聚合,许多稀土化合物与三异丁基铝组成的催化体系都能使两者共聚;尤为突出的是Y(P204)3-Al(i-Bu)3-H2O催化体系对此共聚反应具有优良的优良的催化活性,最大催化效率达6000g/molY,分子量较(η达1.0dl/g)产率在50%以上,应用IR、NMR、GPC等手段对共聚物进行一表征,测理CMT(1)与PO(2)的共聚率分 相似文献
16.
氧化和加氧酶的化学模拟 I. MPc、MTPP/DMF(M=Fe、Co、Cu、Pe和TPP分别为酞菁和四苯基卟啉环;DMF为N-N '二甲基甲酰胺)体系的电子光谱和吸氧动力学 总被引:1,自引:0,他引:1
通过电子光谱法测定MPc的Q_(0-0)带和MTPP的Soret带吸光度随时间的变化, 研究了MP在DMF介质中的吸氧动力学, 按竞争串行反应机理的处理, 表明MP的催化活性有如下关系: MPc>MTPP; Fe>Co>Cu MTPP在空气中的吸氧速率小于在纯氧中的, 其比值约相当于空气中的氧分压; 研究了含硫配体巯基乙醇和含氧配体抗坏血酸对上述体系的影响, 前者使MP谱带发生较大的变化, 吸氧速率常数普遍增大, 后者的影响较小。 相似文献
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New aromatic diimide-dicarboxylic acid having flexible ether linkage, 5-(4-trimellitimidophenoxy)-1-trimellitimido naphthalene, was synthesized by the reaction of trimellitic anhydride with 5-(4-aminophenoxy)-1-naphthylamine. Then, a series of novel aromatic poly(amide-ether-imide)s were prepared by the phosphorylation polycondensation of the synthesized monomer with various aromatic diamines. A model compound was synthesized by the reaction of the monomer with aniline. The resulting polymers with inherent viscosities of 0.43-0.70 dl/g were obtained in high yield. All new compounds including the naphthalene-based monomer, model compound, and the resulted polymers were characterized by FT-IR and NMR spectroscopic methods. The ultraviolet λmax values of the poly(amide-ether-imide)s were also determined. The resulted polymers exhibited a good solubility in a variety of high polar solvents such as N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methyl-2-pyrrolidone (NMP), and pyridine. For some of the polymers obtained the crystallinity behavior was estimated by means of wide-angle X-ray diffraction (WXRD) method, and the resulted polymers exhibited nearly an amorphous nature. Thermal stability of the obtained polymers was determined by thermogravimetric analysis (TGA/DTG), and the 10% weight loss temperatures of the one-step degraded poly(amide-ether-imide)s were found to be in the range between 528 and 551 °C in nitrogen. From differential scanning calorimetric (DSC) analyses, the polymers showed Tgs between 276 and 307 °C. Cyclic voltammetry (CV) measurements of a typical polymer showed that they are also electrochemically stable. 相似文献
19.
以9,9-二(甲氧基甲基)芴(BMMF)为内给电子体的MgCl2/TiCl4催化剂与三乙基铝(TEA)组成典型Ziegler-Natta催化剂体系,催化丙烯本体聚合,考察极少量1,4-戊二烯作为共聚单体对聚合反应行为的影响.结果发现,在[1,4-戊二烯]/[丙烯]共单体摩尔比非常低(0.1%)的范围内,随着1,4-戊二烯浓度增大,催化剂活性迅速降低,[1,4-戊二烯]/[丙烯]比为0.08%时仅为约初始的1/4.但由特性黏数得到的聚合物分子量对1,4-戊二烯浓度呈现不规则变化,1,4-戊二烯并未使聚合物分子量单调降低,而在极低浓度时反而使其有所提高.凝胶渗透色谱(GPC)表征结果不但进一步确认了聚合物分子量的变化规律,还表明1,4-戊二烯并未使聚合物链发生支化.动态剪切流变测试结果显示极少量的1,4-戊二烯使聚合物的剪切黏度上升,模量提高,松弛时间延长;聚合物的拉伸黏度在拉伸流变测试中呈现相同的规律.通过1,4-戊二烯/氢气在聚合反应中协同作用的探讨,提出了对MgCl2/TiCl4/BMMF-TEA催化的丙烯/1,4-戊二烯反常共聚合行为的解释. 相似文献
20.
1,4-环己烷二甲醇对可生物降解聚酯PBS的共聚改性 总被引:4,自引:0,他引:4
在可生物降解聚酯PBS的分子主链中引入具有立体构型的1,4-环己烷二甲醇(CHDM), 对PBS进行了共聚改性. 研究结果表明, 反应时间在2 h内能够得到数均分子量100000以上的P(BS-co-CHDM)共聚物, 随着1,4-CHDM添加量的增加, 共聚物的结晶度降低, 玻璃化转变温度(Tg)呈上升趋势, 当添加量增大时, 共聚物tanδ随之增大, 内耗峰宽逐渐变窄, 当1,4-CHDM添加量为30%时, 断裂伸长率达到1232%. 所有共聚物的热分解温度均在300 ℃以上, 具有良好的热稳定性. 相似文献