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991.
采用 13C交叉极化/魔角旋转-核磁共振(13C CP/MAS NMR)技术对四种煤进行分析,结合化学分析方法,考察了含氧官能团的分布规律,尤其是非活性醚键的含量。结果表明,13C CP/MAS NMR方法可以定量分析煤中部分含氧官能团,四种煤中羧基和羰基的含量分别为0.00~1.41和0.45~1.91 mol/kg;13C CP/MAS NMR与化学分析方法结合,可以定量解析煤中非活性醚键的含量,四种煤的醚键含量值为5.33~10.54 mol/kg,而活性醚键含量仅为0.04~0.13 mol/kg,煤中醚键的赋存状态以非活性醚键为主。 相似文献
992.
A series of 16- and 18-membered azo- and azoxythiacrown ethers have been synthesized by reductive macrocyclization of the respective bis(nitrophenoxy)oxaalkanes. The aromatic residues located in the polyether region of the molecule were introduced to macrocyclic skeletons and their affinities toward different groups of metal cations in ion-selective electrodes were described. X-ray structures for one dinitropodand and one azoxybenzothiacrown exhibiting strong π–π and π–H interactions have been found. 相似文献
993.
In this paper, a broad overview on the applications of different carbon-based nanomaterials, including nanodiamonds, fullerenes, carbon nanotubes, graphene, carbon nanofibers, carbon nanocones-disks and nanohorns, as well as their functionalized forms, in sample preparation is provided. Particular attention has been paid to graphene because many papers regarding its application in this research field are becoming available. The distinctive properties, derivatization methods and application techniques of these materials were summarized and compared. According to their research status and perspective, these nanomaterials were classified in four groups (I: graphene and carbon nanotubes; II: carbon nanofibers; III: fullerenes; and IV: nanodiamonds, carbon nanocones/disks and carbon nanohorns) and characteristics and future trends of every group were discussed. 相似文献
994.
995.
以二苯并18-冠-6,3-氟-4-甲基苯铵盐以及多金属氧酸盐[Mo6O19]2-为原料,使用溶剂挥发法合成了有机无机杂化材料[(3-F-4-MeAnis)(DB[18]crown-6)]2[Mo6O19]·2CH3CN (1)(3-F-4-MeAnis=3-氟-4-甲基苯铵盐;DB[18]crown-6=二苯并18-冠-6);以18-冠-6,2-氟-4-甲基苯铵盐以及多金属氧酸盐[SMo12O40]2-为原料,运用H管扩散法制备了晶体材料[(2-F-4-MeAnis)([18]crown-6)]2[SMo12O40]·2CH3CN (2)(2-F-4-MeAnis=2-氟-4-甲基苯铵盐;[18]crown-6=18-冠-6)。通过红外光谱、元素分析、热重分析和X射线单晶结构分析对化合物进行了表征。结构分析表明,晶体1和2通过非共价键自组装作用构建而成,冠醚基超分子阳离子是通过N-H…O氢键作用形成。在晶体1和2中,超分子阳离子和多酸阴离子交错堆积形成包合物结构,沿着a轴方向观察,发现每个多酸阴离子被6个超分子阳离子包围着形成六边形堆积结构。通过晶体结构研究和热重分析表明,二苯并18-冠-6中的苯环在维持晶体1的稳定性方面具有重要的作用。 相似文献
996.
建立了人体血清中多种环境雌激素:多溴联苯醚、邻苯二甲酸酯和双酚A的快速可靠的连续在线分离及在气相色谱-质谱上的分析方法.血清样品经过浓盐酸使蛋白质变性,用乙醚萃取,经硅胶柱分离出多个族组分:多溴联苯醚(Polybrominated diphenyl ethers,PBDEs)、邻苯二甲酸酯(Phthalate estcrs,PAEs)和双酚A(Bisphenol A,BPA),最后由气相色谱-质谱的选择离子检测测定.PBDEs,PAEs和BPA标准曲线回归方程拟合度R2均大于0.99,表明在测试的浓度范围内线性关系良好.PBDEs目标化合物的检出限为0.005~0.048μg/L,PAEs目标化合物的检出限为0.103~0.833μg/L,BPA的检出限是0.035 μg/L.标准样品重复样中,PBDEs的RSD(relative standard deviation)值分别为2.8%~10.9%;PAEs的RSD值为5.6%~9.9%;BPA的RSD值为3.0%.实际血清样品中,PBDEs的加标回收物PCB209(Polychloride diphenyl ether 209)的回收率范围是74.8%~88.5%;PAEs中的加标回收物DBP-D4(Dibutyl phthalateDeutorium 4)的回收率范围为78.7%~97.0%;BPA中的加标回收物BPA-D16( Bisphenol A-Deutorium 16)的回收率范围是76.3%~93.1%.本方法检测血液中多种环境雌激素灵敏度高、重现性和回收率均良好. 相似文献
997.
《Journal of Coordination Chemistry》2012,65(3-4):359-370
Abstract Methods for the preparation of the 4-diphenylphosphino derivatives of N-phenylaza-15-crown-5 and -18-crown-6 are described. The properties of these systems and the 4′-diphenylphosphino derivative of benzo-15-crown-5 have been examined by way of picrate ion extraction abilities and IR spectra of their Ni(CO)3L (L = these phosphines) complexes. All three have abilities to extract Na+ and K+ that are comparable to benzo-15-crown-5. The IR studies (νCO, A1 band) indicate that the azacrown systems have better ability than the benzocrown system to increase the electron density on the nickel center. Further, the addition of alkali metal ions, Na+ and K+, to the Ni(CO)3L solutions results in maximum shifts of ca 1.5 cm?1 for the former systems and 0.7 cm?1 for the latter system. A rationale for this observation is presented in terms of Hammett substituent constants. Finally, an X-ray structure of the phosphine oxide of the phenylaza-15-crown-5 derivative is presented. A prominent feature of the structure is that the nitrogen atom is essentially planar with the result that the crown ether ring is large and not preorganized for coordination of spherical ions. 相似文献
998.
NETWORKCROWNETHERPOLYMERSWITHCENTRICFUNCTIONALGROUPS.Ⅱ.SYNTHESISOFNETWORKCROWNETHERPOLYMER WITH PENDANT SULFIDE SIDE CHAIN AN... 相似文献
999.
Sadahito Hashidate Yukio Nagasaki Masao Kato Hiro Matsuda Hachiro Nakanishi 《先进技术聚合物》1995,6(9):626-631
Photocrosslinkable second-order nonlinear optical (NLO) polymers were synthesized from cationic copolymerization of a vinyl ether monomer bearing 4′-nitrobiphenyl-4-oxy group as the NLO chromophore with a vinyl ether monomer bearing cinnamoyl group as the photoreactive moiety. To obtain a suitable poling method involving photocrosslinking, which is capable of inducing a higher and more stable second-order nonlinear coefficient, d33, for NLO polymer films, some poling procedures were investigated. An optimized poling method was as follows. Ultraviolet (UV) irradiation is performed for 90 sec during poling at 50°C for 20 min, followed by poling at 150°C for 20 min. By using this poling method NLO polymer films exhibited a higher and considerably stable d33 value at room temperature, even though they had rather lower glass transition temperatures before photocrosslinking. Some photocrosslinking mechanism for NLO polymers investigated here were considered. 相似文献
1000.
标题化合物[(NH_4)(DB18C6)]_2[Ag(SCN)_2]_2其晶体属三斜晶系,空间群为P1。晶胞参数:a=14.003(2),b=14.461(3),c=14.887(2),a=66.51(2),β=66.70(1),γ=76.09(2)°,V=2527.13 3,M_r=1205.0,Z=2,D_x=1.58g/cm~3,μ=9.88cm~(-1)。偏差因子R_w=0.081,独立可观测点数[I>3σ(I)]为3351个,在配合物分子中,二苯并18-冠-6与NH4~+形成配阳离子,Ag~+与硫氰酸根形成配阴离子,二者以静电力形成配合物。银原子被两个SCN~-的S原子桥联和硫氰酸根上的硫,氮杂配,使整个分子形成一条高分子长链。 相似文献