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排序方式: 共有4669条查询结果,搜索用时 31 毫秒
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Kun Guo YANG Rui Mao HUA* Hai WANG Bo Qing XU* Department of Chemistry Tsinghua University Key Laboratory of Organic Optoelectronics & Molecular Engineering of Ministry of Education Beijing Department of Chemistry Chemical Engineering Guangxi Normal University Guilin 《中国化学快报》2005,16(4)
Diphenylmethane and substituted diphenylmethane are important compounds forsynthesis chemistry as well as industrial chemistry. These compounds are easilysynthesized by the benzylation of aromatic compounds with benzyl chloride or benzylalcohol catalyzed by homogeneous acid catalysts, such as AlCl3, FeCl3, H2SO4, HF andBF3. However, these catalytic systems are highly corrosive, and usually proceed withlow selectivity. In addition, they are less satisfactory from the environmen… 相似文献
94.
Luminescentmaterialshavinglongdecayperi0dhaveat-IIactedmuchinterestduetotheirpotentialwidespreadaPplicati0ns.Recently,alongdecayluminescentp0wderhavingthecomPositionofSrAl2O4activatedwithEu' wasreportedandregardedasthebestcandidateforpracticalaPPlicationbecauseofitsuniqueadVantages0veritsprecursors.l'2Inthispaper,wereportthesynthesisofthelongdecayluminescentpowderandtheinnuence0fthemolarratioofAlt0sr0ntheethessioncolor.Toproducethelundnescentp0wder,amixtureofSrCO3,Al2O3,Eu2O3andsomesol… 相似文献
95.
消毒剂产品中三氯新的测定及其稳定性研究 总被引:9,自引:0,他引:9
采用反相高效液相法测定消毒剂产品中的三氯新。在KromasilC18柱 (2 0 0mm× 4 6mmi d )上 ,以甲醇 乙腈 水 (含 0 0 2mol/LKH2 PO4,pH 2 7) (体积比为 4 0∶4 0∶2 0 )溶液为流动相 ,2 80nm波长下检测 ,样品用流动相超声溶解。三氯新的回收率为 94 2 %~ 10 2 2 % ,相对标准偏差 (RSD)为 2 2 %~ 3 0 %。方法操作简便 ,精密度和准确度高 ,适合三氯新的快速分析。在 5 4℃时保存 14d和 37℃时保存 90d后 ,标准品和样品的含量没有明显变化 ,证明三氯新具有良好的稳定性。 相似文献
96.
离子性指数、极化效应指数烷烃^13C NMR化学位移的 关系研究 总被引:5,自引:0,他引:5
定义了烷烃分子中碳原子的离子性指数(INI),用离子性指数(INI)、极化效应指数(PEI)及N^i~H(i=αβΥ)结构信息参数研究了烷烃的^13CNMR化学位移模型,结果表明,烷烃^13CNMR化学位移(CS)可用下式来定量描述:CS=194.6156-37.7394(INI)+98.6505(ΣPEI)+27.1630(INI/ΣPEI)-652.9106(ΣPEI/INI)+0.7735N^α~H+2.2468N^β~H-0.1742N^γ~H。用上式估算了304个碳原子的化学位移,平均绝对误差仅为0.77δ,标准差0.9860δ,预测值与实验值非常吻合。 相似文献
97.
Hai B Wu J Chen X Protasiewicz JD Scherson DA 《Langmuir : the ACS journal of surfaces and colloids》2005,21(7):3104-3105
Hematite nanoparticles have been functionalized with a self-assembled monolayer of undecanoic acid (UA) by covalent attachment via siloxane groups. The number density of carboxylic/carboxylate groups on the surface was determined by titration, yielding values on the order of 10(14) UA molecules/cm(2) and thus consistent with a closed-packed monolayer. The ability of these functionalized particles to adsorb Cd(2+) in the ppm range was demonstrated using in situ anodic stripping voltammetry. 相似文献
98.
TaoJIANG BuXingHAN GuoYingZHAO ZhongHaoLI YanHongCHANG HaiXiangGAO JunChunLI 《中国化学快报》2004,15(3):296-299
The oxidation of styrene with molecular oxygen catalyzed by PdCl2 CuCl2 has been investigated in supercritical CO2 with a batch reactor. The oxidative system of styrene contains four components at the beginning and seven components during the reaction. The critical temperature, critical pressure, and critical density at different conversions are determined by using a high-pressure view cell. The effect of phase behavior on the conversion and selectivity were studied. Experimental results showed that the critical parameters of the reaction mixture at fixed initial molar ratio changed with the conversion of reactant. The conversion of styrene reached maximum near the critical density of the reaction mixture. Product selectivity also varied with density of reaction mixture and could be tuned to some degree. 相似文献
99.
Kim MS Seo KS Khang G Lee HB 《Langmuir : the ACS journal of surfaces and colloids》2005,21(9):4066-4070
A gradient polyethylene (PE) surface was created through corona treatment, in which the corona power increased along the 5 cm length of the PE. The gradient surface was treated with polyethyleneimine and then biotin. Fluorescein-conjugated streptavidin (SAV) caged within 5-carboxymethoxy-2-nitrobenzyl (CMNB) adsorbed onto the biotinylated gradient PE surface following molecular recognition principles. Photoirradiation decomposed the CMNB cage and allowed the fluorescein-conjugated SAV to fluoresce, the intensity of which increased gradually along the PE surface. 相似文献
100.
Xing Hai Li Xin Ling Yang Xiao Mei Liang Zhen Peng Kai Yun Ling Fu Heng Chen Dao Quan Wang 《中国化学快报》2007,18(12):1476-1478
α-Chlorocycloalkanones(Ⅳ) were synthesized from cycloalkanones via potassiumα-oxocycloalkylsulfonates(Ⅱ).A two-step mechanism was proposed to explain the formation ofⅣfromⅡ. 相似文献