排序方式: 共有8条查询结果,搜索用时 171 毫秒
1
1.
2.
用键共振能(BRE)和拓扑共振能(TRE)方法,对由从富勒烯C_(40)(D_(5d))产生的富勒烯氢化物C_(40)H_2H所有可能异构体的芳香性进行了研究。研究了氢原子加成位置和芳香性之间的关系。计算结果表明,氢原子的加成位置与C_(40)(D_(5d))中各键的键共振能直接有关。在C_(40)(D_(5d))中C3类碳原子具有最大的反应活性。大部分C_(40)H_2异构体的芳香性高于C_(40)。用拓扑共振能方法得到的C_(40)H_2异构体的稳定性顺序与AM1和PM3半经验方法得到的稳定性顺序是一致的,用键共振能和拓扑共振能方法同样地能预测富勒烯氢化物的稳定性。 相似文献
3.
用拓扑共振能(TRE)和百分拓扑共振能(%TRE)方法,对由富勒烯C28(Td)产生的C26BN各种可能异构体和它们阴离子的芳香性进行了研究。探讨了C26BN异构体稳定性与杂原子取代位置间的关系。最后,用最小键共振能(min BRE)方法对C28(Td)和C26BN分子离子的动力学稳定性进行了研究。研究结果表明C28(Td)和C26BN在中性状态下,因TRE为负值被预测为具有反芳香性。Min BRE方法研究结果证明了C28(Td)和C26BN的动力学不稳定性与分子中具有较高反芳香性键直接有关。TRE和min BRE方法研究结果表明,C284-和C26BN4-各异构体不仅具有较高的芳香性而且也有较高的动力学稳定性。 相似文献
4.
Xirali Mamtimin Abduwasit Tursun Rukiya Matsidik Sayyare Sidik Kamarnisa Abdulla Hayrulla Mamut Ablikim Obulda Ismayil Nurulla 《应用聚合物科学杂志》2014,131(23)
A new type of low‐molecular‐weight polypyrimidine in a π‐conjugated main chain was prepared by a Grignard reaction between 2‐amino‐4,6‐dichloropyrimidine and 1,4‐dibromo‐2,5‐didodecyloxybenzene in the presence of [1,2‐Bis(diphenylphosphino) ethane]dichloronickel(II). The structure of the copolymer was fully elucidated by Fourier transform infrared spectroscopy, 1H‐NMR, and elemental analysis. The copolymer had good solubility in common organic solvents. The copolymer displayed a bathochromic shift when protonated with an organic or inorganic acid in chloroform or tetrahydrofuran. The copolymer depicted facile p‐doping and good electron‐transporting electrochemical properties in a 1M H2SO4 aqueous solution. The copolymer showed a narrow polydispersity of 1.04. Thermogravimetric analysis showed that the copolymer had a certain thermal stability with no decomposition at a temperature of 250°C under N2. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41174. 相似文献
5.
Liang Chen Junhua Li Wijdan Ablikim Jun Wang Huazhen Chang Lei Ma Jiayu Xu Maofa Ge Hamidreza Arandiyan 《Catalysis Letters》2011,141(12):1859-1864
Abstract
A series of cerium-tungsten oxide catalysts was prepared by the co-precipitation method and was evaluated for the selective catalytic reduction of NO x by ammonia (NH3-SCR) over a wide temperature range. These catalysts were characterized by BET, XRD, XPS and H2-TPR analyses. The experimental studies demonstrated that, among cerium-tungsten oxides, CeO2–WO3 with a Ce/W molar ratio of 3/2 exhibited the best activity toward NH3-SCR reactions, N2 selectivity and SO2 durability over a broad temperature range of 175–500 °C at a space velocity of 47,000 h−1. The strong interaction between Ce and W could be the main factor leading to the high activity of the CeO2–WO3 mixed oxide catalyst. 相似文献6.
7.
调查白土精制装置蒸发塔真空系统的运行状况,发现真空系统塔顶馏出油线、塔顶冷却器、馏油罐出现严重的腐蚀。冷却器不锈钢管束前后出现腐蚀穿孔3次,堵管12根,冷却器壳体上部有均匀褐色垢,垢厚约1 mm。通过分析,查明了白土装置蒸发汽提塔真空系统腐蚀的原因和腐蚀介质的来源。从腐蚀调查看来,白土本身成酸性,且含有硫酸根、氯离子等杂质,这些物质在白土精制过程中,会由加工处理的油品带出,并溶于水中,形成低浓度的硫酸、盐酸的混合水溶液是导致蒸发塔顶真空系统严重腐蚀的根源。为了降低腐蚀对设备的危害,从设备和工艺方面进行了防护:增加涂料防护、材质升级;变更工艺流程和注入缓释剂等。工业应用效果说明,这些措施很好地解决了影响装置安全生产的设备腐蚀问题。 相似文献
8.
C22 BxNy(x+y=2)全部异构体和分子离子芳香性的研究 总被引:1,自引:0,他引:1
用拓扑共振能(TRE)和百分拓扑共振能(%TRE)方法,研究从富勒烯C24(D6)产生异质富勒烯C22N2,C22B2和C22BN的所有异构体,研究阳离子和阴离子的芳香性.分析C22BxNy中杂原子取代位置和稳定性之间的关系.结果,中性状态和阳离子状态中,各异构体的TRE都为负数具有反芳香性.但它们的高价阴离子的TRE都为正数则有芳香性.中性状态中,稳定性顺序为:C22N2(1-19)>C22BN(39-64)>C24>C22B2(20-38).形成闭壳层结构时稳定性顺序为:C22B8-2(20-38>C6-24>C22BN6-(39-64)>C22N4-2(1-19).无论在中性状态还是闭壳层结构,当N原子取代C2类碳原子,B原子取代C1类碳原子时最稳定.理论上,预测C22BxNy的高价阴离子有合成的可能性. 相似文献
1