双马来酰亚胺增韧研究Ⅱ.链扩展双马来酰亚胺及其树脂的合成及表征

合成了一系列结构不同和链长短不一的双马来酰亚胺，并对其结构和性能作了表征，同时研究了它们的固化反应和固化产物的性能。用双马来酰亚胺和二烯丙基化合物反应制造了增韧树脂，研究了该树脂的固化和热稳定性。     

铁(III)卟啉催化β-胡萝卜素分解动力学研究

使用BeckmannDU-8B紫外可见分光光度计研究了以氯合四－间三甲苯基卟啉铁（Ⅲ）（FeTMPCl）为催化剂，间氯过氧化苯甲酸（mCPBA）为氧化剂，咪唑（I_m）、2－甲基咪唑（MeI_m）、2－乙基－4－甲基咪唑（EMI_m）为轴向配体，催化β-胡萝卜素（β－cte）氧化分解为维生素A的动力学规律，提出了反应机理，研究了温度、催化剂浓度、氧化剂浓度及轴向配体对反应速率的影响，应用Gauss－Newton－Marquardt方法求得各基元反应的有关动力学参数．     

ZrO2对Mn—O／γ—Al2O3催化剂中表面氧性能的影响

用ＴＰＤ－ＭＳ和ＴＰＲ技术研究了Ｍｎ－Ｏ／γ－Ａｌ２Ｏ３和Ｍｎ－Ｏ／ＺｒＯ＋γ－Ａｌ２Ｏ３催化剂中表面氧的脱附、还原性能和再生氧化恢复性能，并用ＸＲＤ对催化剂的固相结构进行了表征。结果表明，Ｍｎ－Ｏ／γ－Ａｌ２Ｏ３或Ｍｎ－Ｏ／ＺｒＯ２＋γ－Ａｌ２Ｏ３催化剂上存在ＭｎＯ２、Ｍｎ２Ｏ３和少量Ｍｎ３Ｏ４物种。ＺｒＯ２的存在不影响Ｍｎ－Ｏ／γ－Ａｌ２Ｏ３的ＴＰＲ的ＴＰＤ的特征峰，但使ＭｎＯ２的量明显增加，     

离子色谱柱切换技术同时测定食品中的多种成分

采用离子色谱柱切换技术同时测定了保留性质差别较大的有机酸以及不同价态的无机阴离子。由于柱切换基本不影响色谱基线,该法有较高的灵敏度。同时测定了食品中的乙酸,山梨酸、苯甲酸、糖精、氯离子和磷酸根。     

Nation-Teflon bimembrane-supported palladium catalysts for Suzuki coupling reactions

Nation-Teflon bimembrane was used as an efficient support for the preparation and application of heterogeneous palladium catalysts.The supported palladium catalysts exhibit high activity and stability in the Suzuki cross-coupling of aryl bromides with arylboronic acids to afford the corresponding biaryls in good to excellent yields,and can be readily recovered and reused several times without significant loss of activity.     

Synthesis, characterization and luminescence study of dimethyl(β-ketoiminato)gallium (-indium) complexes: crystal structure of dimethyl[1-phenyl-3-N-(4-methoxyphenylimino)-1-butanonato]gallium

Six dimethylgallium (indium) complexes of type Me₂ML [M = Ga, L = 1-phenyl-3-N-(phenylimino)-1-butanonato (1), 1-phenyl-3-N-(p-methoxyphenylimino)-1-butanonato (2), 1-phenyl-3-N-(o-chloro phenylimino)-1-butanonato (3); M = In, L = 1-phenyl-3-N-(phenyl imino)-1-butanonato (4), 1-phenyl-3-N-(p-methoxyphenylimino)-1-butanonato (5), 1-phenyl-3-N-(o-chlorophenylimino)-1-butanonato (6)] have been synthesized by reaction of trimethylgallium (indium) with appropriate 1-phenyl-3-N-(arylimino)-1-butanones. The complexes obtained have been characterized by elemental analysis, ¹H NMR, IR and mass spectroscopy. Structure of 2 has been determined by X-ray single-crystal analysis, in which Ga atom is four coordinated. Complexes 1-6 emit colors from blue to green (463-491 nm) when irradiated by UV light. The electroluminescent (EL) properties of 1-6 were examined by fabricating EL devices using 1-6 as emitter, respectively. The EL bands are located in the green region (509-522 nm).     

Emulsion polymerization of methyl methacrylate under pulsed microwave irradiation

Emulsion polymerization of methyl methacrylate (MMA) under pulsed microwave irradiation (PMI) with higher peak pulse power was studied. The effects of various parameters of PMI on the polymerization were analyzed and compared with that under conventional heating (CH) process. The results were summarized, as compared with that under CH, as follows. The amount of initiator used to reach constant conversion reduced by 50% at the same polymerization time; at the same initiator concentration 0.15 and 0.2 wt.%, the polymerization rate increased by 131% and 163%, respectively. The molecular weight of polymer obtained was 1.1-2.0 times larger than that under CH; at the same irradiation energy, the conversion achieved using a lower pulse power was greater than that using a higher pulse power. There seemed to be a factor of the irradiation energy efficiency; in other words, for the monomer conversion, the irradiation energy of low pulse power had a higher efficiency. The conversion achieved using a 3.5 μs pulse width was almost the same as that using a 1.5 μs pulse width. The results indicated that PMI had a significant non-thermal effect on the emulsion polymerization of MMA so as to effectively enhance the polymerization rate. The glass transition temperature (T_g), the polydispersity index (PDI) and the regularity of the polymer obtained using two processes were similar, indicating that the physical properties and microstructure of the polymer were not modified by the use of microwaves.     

Study of a mathematical model of metal ion complexes in solvent sublation

Separation of metal ion complex, [(C(12)H(8)N(2))(3)Fe(2+)], with surfactant sodium dodecylphrate (DLS) complex from aqueous phase was carried out by solvent sublation, which obeys first-order kinetics. On the base of the complete transport mechanisms, the Langmuir adsorption, and the ion complex equilibrium in the aqueous phase, a mathematical model for the [(C(12)H(8)N(2))(3)Fe(2+)]-surfactant ion complex is obtained with the aid of the Mathematic 4.0 program, 4th Runge-Kutta method, and the Matlab programs. The effects of many parameters, such as K(a), K(l), K(ow), d(i), V(o), V(w), and Q(a), on solvent sublation are investigated. Furthermore, the simulation showed that the model is substantiated for experiments on the solvent sublation of the complex.     

Photocurrent generation in multilayer self-assembly films fabricated from water-soluble poly(phenylene vinylene)

A novel, water-soluble, cationic PPV derivative poly[(2,5-bis(3-bromotrimethylammoniopropoxy)-phenylene-1,4-divinylene)-alt-1,4-(2,5-bis(2-(2-hydroxyethoxy)ethoxy))phenylene vinylene] (BH-PPV) has been synthesized by a Heck coupling reaction. Multilayered assemblies of the BH-PPV and the sodium salt of hexa(sulfobutyl)fullerenes (C(60)-HS) were fabricated successfully by an alternate deposition technique. The multilayer structures were studied by UV/Vis spectroscopy, small angle X-ray diffraction, and atomic force microscopy. The photoinduced charge transfer property of the self-assembled multilayer film was also measured by a three-electrode cell technique. A steady and rapid cathodic 5.5 microA cm(-2) photocurrent response was measured as the irradiation of the multilayer film was switched on and off. Importantly, the response of on/off cycling is prompt and reproducible. A possible mechanism for the electron-transfer process is proposed.     

Thermodynamics and kinetics of the hydride-transfer cycles for 1-aryl-1,4-dihydronicotinamide and its 1,2-dihydroisomer

Five 1-(p-substituted phenyl)-1,4-dihydronicotinamides (GPNAH-1,4-H(2)) and five 1-(p-substituted phenyl)-1,2-dihydronicotinamides (GPNAH-1,2-H(2)) were synthesized, which were used to mimic NAD(P)H coenzyme and its 1,2-dihydroisomer reductions, respectively. When the 1,4-dihydropyridine (GPNAH-1,4-H(2)) and the 1,2-dihydroisomer (GPNAH-1,2-H(2)) were treated with p-trifluoromethylbenzylidenemalononitrile (S) as a hydride acceptor, both reactions gave the same products: pyridinium derivative (GPNA(+)) and carbanion SH(-) by a hydride one-step transfer. Thermodynamic analysis on the two reactions shows that the hydride transfer from the 1,2-dihydropyridine is much more favorable than the hydride transfer from the corresponding 1,4-dihydroisomer, but the kinetic examination displays that the former reaction is remarkably slower than the latter reaction, which is mainly due to much more negative activation entropy for the former reaction. When the formed pyridinium derivative (GPNA(+)) was treated with SH(-), the major reduced product was the corresponding 1,4-dihydropyridine along with a trace of the 1,2-dihydroisomer. Thermodynamic and kinetic analyses on the hydride transfer from SH(-) to GPNA(+) all suggest that the 4-position on the pyridinium ring in GPNA(+) is much easier to accept the hydride than the 2-position, which indicates that when the 1,4-dihydropyridine is used the hydride donor to react with S, the formed pyridinium derivative GPNA(+) may return to the 1,4-dihydropyridine by a hydride transfer cycle; but when the 1,2-dihydropyridine is used as the hydride donor, the formed pyridinium derivative can not return to the 1,2-dihydropyridine by the hydride reverse transfer from SH(-) to GPNA(+). These results clearly show that the hydride-transfer cycle is favorable for the 1,4-dihydronicotinamides, but unfavorable for the corresponding 1,2-dihydroisomers.