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化学修饰石墨探针预富集-石墨炉原子吸收法测定Cr(Ⅵ)和Cr(Ⅲ) 总被引:2,自引:0,他引:2
本文将化学修饰石墨探针选择性预分离富集和石墨炉探针原子化测定的高灵敏度结合起来,建立了用TOPO修饰的石墨探针络合富集Cr(Ⅵ)、Nafion修饰的石墨探针交换富集Cr(Ⅲ)的双修饰石墨探针顺序预分离富集、石墨炉探针原子化法测定水体中Cr(Ⅵ)和Cr(Ⅲ)的方法。Cr(Ⅲ)的检出限为1.03ng/mL,线性范围为0~51ng/mL。Cr(Ⅵ)的检出限为0.37ng/mL,线性范围为0~81ng/mL。用Cr(Ⅲ)与Cr(Ⅵ)合成样品进行回收实验,回收率对Cr(Ⅲ)与Cr(Ⅵ)分别为95%~98%与98%~102%,利用所建立的方法测定了清华运河水样和实验室自来水样,获得了满意的结果。 相似文献
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在硫酸铵存在下硫氰酸铵-孔雀绿-水液-固体系浮选分离汞(Ⅱ) 总被引:30,自引:0,他引:30
研究了在硫酸铵存在下硫氰酸铵-孔雀绿-水液-固体系浮选分离汞(Ⅱ)的行为及其与常见离子分离的条件。实验表明,在一定条件下,控制酸度条件,可实现Hg(Ⅱ)与常见离子Ni(Ⅱ),Mn(Ⅱ),Fe(Ⅱ),Bi(Ⅲ),Co(Ⅱ),Al(Ⅲ),Cr(Ⅲ),Cd(Ⅱ)分离,对合成水样及工业废水进行定量浮选分离测定,结果与双硫腙法相符。 相似文献
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甲基磺酰氯的新合成方法甄小丽,康汝洪,韩建荣(河北轻化工学院基础部,石家庄050018)(河北师范大学化学系,石家庄050016)甲基磺酰氯是合成医药、农药的重要化工原料;也是酯化、聚合反应的催化剂;蒽醌,咔唑类染料的氯化剂;油墨、涂料的速固剂等,用... 相似文献
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应用带有分子碎片相互作用、分子轨道分析等功能的量子化学程序MOAN及分子动力学模拟软件Materials Studio计算了矿物表面的电子结构及其与巯基类浮选剂的相互作用.确定了矿物相的最可几计算模型,提出了合理的吸附作用模型及浮选剂在矿物表面的吸附排列方式,对其吸附作用机理及吸附剂与矿物表面之间的多种电子转移形式作了合理解释,发现巯基苯并类浮选剂的p-π共轭结构对浮选作用有重要的影响,从理论上确定的矿物表面单位面积内单层饱和吸附分子数与实验值接近.讨论了三种不同共轭效应、诱导效应的官能团取代浮选剂的苯环氢原子,对浮选剂的活性及选择性的影响.本研究将对理解浮选的高捕收性和选择性有着重要的意义,直接指导定向合成新型高效浮选剂,浮选试验结果与理论计算基本一致. 相似文献
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Cr(VI)及Cr(Ⅲ)混合物中Cr(Ⅵ)的原子吸收测定:Cr(TTA)3… 总被引:3,自引:0,他引:3
在pH5.7的乙酸-乙酸钠缓冲介质中,噻吩甲酰三氟丙酮(TTA)与Cr(Ⅲ)络合,生成的络合物具有挥发性。Cr(Ⅵ)在同样条件下不发生反应。利用此特点可实现Cr(Ⅵ)和Cr(Ⅲ)在石墨炉内分离并测定Cr(Ⅵ)。研究了影响Cr(Ⅲ)与TTA络合的反应酸度、试剂加入量、静置时间等条件,并对石墨炉内定量挥发Cr(Ⅲ),保留Cr(Ⅵ)的原子化条件进行了探讨,所拟定的方法用于合成水样分析,获得满意结果。 相似文献
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采用自蔓延+熔铸法制备Al-Ti-C晶粒细化剂。通过光学显微镜(OM)、透射电镜(TEM)、扫描电镜(SEM)、X射线衍射仪(XRD)和能谱分析(EDS)等手段,研究了稀土镧对晶粒细化剂的组织结构和细化性能的影响。结果表明:镧极大地提高了石墨在铝熔体中的润湿性;镧的加入改变了TiAl3和TiC的形貌、数量和分布,使块状TiAl3和非团簇状TiC均匀分布在α—Al基体上,从而对工业纯铝产生优异的晶粒细化效果。 相似文献
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温欣荣 《理化检验(化学分册)》2003,39(2):74-75,79
研究了硝酸钠-碘化钾-氯化十六烷基吡啶体系浮选分离铅(Ⅱ)的行为及其与常见离子分离的条件。结果表明,控制PH5.0,在1.0gNaNO3存在下,当0.1mol.L^-1碘化钾和0.01mol.L^-1氯化十六烷基吡啶溶液的用量均为1.0ml时,铅(Ⅱ)被定量浮选而与Fe^2 ,Co^2 ,Ni^2 ,Zn^2 ,Mn^2 ,Al^3 等离子分离,对合成水样进行了定量浮选分离测定,结果满意。 相似文献
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乙二胺衍生物的新合成法 总被引:2,自引:0,他引:2
乙二胺衍生物的新合成法史真,王建华,赵莉,卢心中(西北大学化学系,西安710069)(陕西教育学院化学系,西安710061)乙二胺衍生物是合成表面活性剂、抗静电剂、柔软剂、杀菌剂的重要中间体[1,2],研究其新的简便的合成方法有重要意义。作者曾首次提... 相似文献
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在硝酸钠存在下以三元缔合物形态浮选分离钯(Ⅱ) 总被引:1,自引:0,他引:1
在水溶液中,钯(Ⅱ)与硫氰酸铵、十六烷基三甲基溴化铵形成不溶于水的三元缔合物,在少量硝酸钠存在下,此三元缔合物沉淀浮于盐水相上层形成界面清晰的液-固两相,当溶液中十六烷基三甲基溴化铵、硫氰酸铵和硝酸钠的浓度分别为1×10^-3mol·L^-1,1.5×10^-2mol·L^-1,50g·L^-1,pH3.0时,钯(Ⅱ)被定量浮选。而铬(Ⅲ)、锰(Ⅱ)、镍(Ⅱ)、铝(Ⅲ)、钼(Ⅵ)、锌(Ⅱ)、铁(Ⅱ)在该体系中不被浮选,对合成水样和钯镍电镀废液中钯(Ⅱ)进行定量浮选分离测定。 相似文献
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Rui Zhang Chuanliu Wang Qiaohong Yue Tiecheng Zhou Na Li Hanqi Zhang Xiaoke Hao 《Journal of separation science》2014,37(21):3133-3141
An ionic liquid foam floatation coupled with ionic liquid dispersive liquid–liquid microextraction method was proposed for the extraction and concentration of 17‐α‐estradiol, 17‐β‐estradiol‐benzoate, and quinestrol in environmental water samples by high‐performance liquid chromatography with fluorescence detection. 1‐Hexyl‐3‐methylimidazolium tetrafluoroborate was applied as foaming agent in the foam flotation process and dispersive solvent in microextraction. The introduction of the ion‐pairing and salting‐out agent NH4PF6 was beneficial to the improvement of recoveries for the hydrophobic ionic liquid phase and analytes. Parameters of the proposed method including concentration of 1‐hexyl‐3‐methylimidazolium tetrafluoroborate, flow rate of carrier gas, floatation time, types and concentration of ionic liquids, salt concentration in samples, extraction time, and centrifugation time were evaluated. The recoveries were between 98 and 105% with relative standard deviations lower than 7% for lake water and well water samples. The isolation of the target compounds from the water was found to be efficient, and the enrichment factors ranged from 4445 to 4632. This developing method is free of volatile organic solvents compared with regular extraction. Based on the unique properties of ionic liquids, the application of foam floatation, and dispersive liquid–liquid microextraction was widened. 相似文献
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Cyrille Boyer Anthony Granville Thomas P. Davis Volga Bulmus 《Journal of polymer science. Part A, Polymer chemistry》2009,47(15):3773-3794
An investigation into the aminolysis of ω‐end groups of RAFT‐polymers and simultaneous thiol‐ene reactions with ene‐bearing compounds is described. Three different polymers, P(MMA), P(HPMA), and P(NIPAAm), with low PDIs were synthesized using dithiobenzoate and trithiocarbonate RAFT agents. P(NIPAAm) synthesized with trithiocarbonate RAFT agent and P(HPMA) synthesized with dithiobenzoate RAFT agent were both functionalized with a methacrylate‐modified mannose and a maleimide‐modified biotin via one‐pot simultaneous aminolysis and thiol‐ene reactions with product yields above 85%. The presence of ene‐compounds during aminolysis was shown to prevent the formation of disulfide interchain crosslinking. Using the same approach, P(MMA), P(HPMA), and P(NIPAAm) were converted to (meth)acrylate macromonomers with high yields (>80%). In the case of P(MMA), the simultaneous aminolysis and thiol‐ene addition prevented any intrachain side reactions, i.e., thiolactone formation. New architectures such as graft and block copolymers were successfully generated from the macromonomers. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3773–3794, 2009 相似文献
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反相乳液聚合法合成高分子量聚丙烯酸钠 总被引:4,自引:0,他引:4
以丙烯酰氧基Span-80为乳化剂,采用反相乳液聚合法合成了高分子量聚丙烯酸钠.研究了乳化剂和中和度对聚合体系稳定性的影响,以及(NH4)2S2O8—甲基丙烯酸-N、N-二甲氨基乙酯(DMAEMA)—NaHSO3引发剂和单体浓度对聚合物分子量的影响.结果表明,最佳的实验条件:中和度为90%;乳化剂用量为3%(油相);引发剂占单体的质量分数分别为(NH4)2S2O80.06%、DMAEMA0.04%、NaHSO30.02%;单体在水相的质量分数为40%(水相).在最佳实验条件下,合成聚合物分子量超过2.6×107,且溶解性能优于溶液聚合所得产品. 相似文献
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穿心莲内酯的溶剂浮选 总被引:2,自引:0,他引:2
应用溶剂浮选法对穿心莲乙醇提取液中的穿心莲内酯进行分离富集,优化了穿心莲内酯的浮选条件.实验表明:浮选溶剂为乙酸乙酯,水相与有机相体积比为2: 1,加入水相体积4%的乙醇,溶液pH 7,氮气流速200 mL/min,浮选时间40 min为最佳浮选条件.在最佳实验条件下,穿心莲内酯平均收率为94.1%; RSD为1.1%,平均标准加入回收率95.1%; 富集倍数为9.7倍.溶剂浮选法分离穿心莲内酯不仅能得到满意的回收率和富集倍数,并能有效地除去水溶性杂质,提高目标物纯度.与溶剂萃取法相比, 溶剂浮选法能节约有机溶剂和操作时间. 相似文献
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[reaction: see text] 2'-Deoxy-2'-C-difluoromethylene-4'-thiocytidine (4) as a potential antitumor agent was synthesized starting from L-xylose via 2-deoxy-2-C-difluoromethylene-4-thiosugar as a key intermediate. An elimination product, 8, was always formed as the major product during removal of the protecting groups under acidic or basic conditions. However, utilizing neutral reaction conditions to remove the protecting groups afforded the desired product 4 exclusively. 相似文献
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Kuo SC Chen F Hou D Kim-Meade A Bernard C Liu J Levy S Wu GG 《The Journal of organic chemistry》2003,68(12):4984-4987
A novel enantioselective alkylation of double benzylic substrates with secondary electrophiles is reported. A simple norephedrine-based chiral ligand was synthesized that gives alkylation product in 95% yield and 95% ee. A unique water effect on the enantioselectivity was unveiled. Good to excellent ee values were obtained with a number of double benzylic substrates and secondary electrophiles. This novel reaction has been applied to the synthesis of a promising anticancer agent. 相似文献