共查询到19条相似文献,搜索用时 62 毫秒
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用吸收光谱法研究亚甲蓝在表面活性剂存在时的聚合状态 总被引:5,自引:0,他引:5
应用紫外-可见吸收光谱研究了光敏试剂亚甲蓝在溶液中的聚合状态及其与表面活性剂之间的关系。当添加阴离子表面活性剂的浓度于其临界胶束浓度时,亚甲蓝二聚体的比例将出现一极大值;用环己烷剂萃取后,测得亚甲蓝二聚体的吸收光谱,其最大吸收波长位于604nm。 相似文献
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通过四波混频差频的方法产生高分辨的真空紫外激光,用以测量143.6至146.9 nm范围内的射流冷却N_2O分子吸收光谱,对应于C~1Ⅱ←Ⅹ~1∑~+的吸收跃迁.谱图显示出三个分立的振动谱峰叠加在宽吸收背景上,谱峰间隔分别是521和482 cm~(-1).前人的高精度量子化学计算表明C~1Ⅱ态在N-O键长方向表现为无势垒的排斥态.而在N-N键伸缩及N_2O弯曲振动方向则表现为束缚态,因此观测到的振动谱峰被归属为激发态的Feshbach共振.通过反Fourier变换可以得到Feshbach共振对应的非稳定周期轨道的特征周期为61 fs,相应的振动频率为546 cm~(-1).鉴于这一频率与弯曲振动频率非常接近,非稳定周期轨道被认为是由C~1Ⅱ态的弯曲振动与解离运动相互作用而形成的,N-N伸缩振动没有参与形成非稳定周期轨道.由此,N_2O分子C~1Ⅱ态光激发-解离过程得以清晰地阐述. 相似文献
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为从分子水平认识亚甲蓝(MB)分子与大分子之间相互作用机理,应用吸收光谱法研究了MB与十二烷基硫酸钠(SDS)之间相互作用机理,考察了乙醇、氯化钠、羟丙基-β-环糊精以及Triton X-100对相互作用的影响。结果表明:MB与SDS之间能发生相互作用形成复合物产生变色反应,乙醇等对相互作用都有影响。认为MB与SDS变色反应机理是在MB与SDS大分子间发生静电相互作用基础上,结合在SDS有序集合体上MB分子定向聚集所引起的。 相似文献
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通过四波混频差频的方法产生高分辨的真空紫外激光,用以测量143.6至146.9 nm范围内的射流冷却N2O分子吸收光谱,对应于C1Π←X1Σ+的吸收跃迁.谱图显示出三个分立的振动谱峰叠加在宽吸收背景上,谱峰间隔分别是521和482 cm-1.前人的高精度量子化学计算表明C1Π态在N—O键长方向表现为无势垒的排斥态,而在N—N键伸缩及N2O弯曲振动方向则表现为束缚态,因此观测到的振动谱峰被归属为激发态的Feshbach共振.通过反Fourier变换可以得到Feshbach共振对应的非稳定周期轨道的特征周期为61 fs,相应的振动频率为546 cm-1.鉴于这一频率与弯曲振动频率非常接近,非稳定周期轨道被认为是由C1Π态的弯曲振动与解离运动相互作用而形成的,N—N伸缩振动没有参与形成非稳定周期轨道.由此,N2O分子C1Π态光激发-解离过程得以清晰地阐述. 相似文献
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溴酚蓝和亚甲蓝双显色体系萃取光度法测定铜 总被引:4,自引:0,他引:4
向三元络合物[Cu(phen)_3)BPB的二氯乙烷萃取液中,加入KCN水溶液,形成的[Cu(CN)_2)~-和溴酚蓝离子(BPB)进入水相,向其中加入与BPB颜色相近的亚甲蓝(MB)再进行萃取光度测定。因萃取液中[MB_2BPB)和[Cu(CN)_2)MB两者的吸光作用,使本方法具有很高的灵敏度,ε=1.77×10~5L·mol~(-1)·cm~(-1)。铜含量在0~5μg/25ml遵从比耳定律,对含铜量为10~(-8)g/ml的水样测定5次,相对标准偏差为2%。 相似文献
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尽管叠氮二乙基铝Et2AlN3(DEAA)是一个重要的化合物,但人们对它研究还是很少的。本文通过温度-蒸气压关系研究了纯态DEAA的三聚体和单量体之间的缔合-解离平衡;通过相对分子质量测定、核磁共振氢谱和核磁共振铝谱的测定,研究了在苯和甲苯溶液中DEAA的三聚体和单量体之间的缔合-解离平衡。借助温度-蒸气压曲线分别计算了DEAA三聚体和单量体的气化焓和解离焓;通过相对分子质量测定、核磁共振铝谱测定等方法计算得到了溶液中DEAA三聚体和单量体的解离平衡常数、解离焓和解离熵等热力学数据。 相似文献
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L'ubica Adamíková Katarína Pavlíková Peter evík 《Reaction Kinetics and Catalysis Letters》2000,69(1):91-94
The decomposition of methylene blue in aqueous alkaline solution is described. The rate equation is of the form:
, where k = 9.0 × 10-4 mol- [dm3s-1 at 20°C and] = 0.5 mol dm-3. 相似文献
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The monomer‐dimer equilibrium of methylene blue (MB, Scheme I) has been investigated by means of UV‐Visible spectroscopy in aqueous solutions. The self aggregation of MB in water has been investigated by recording absorption spectra in the wavelength range of 450–750 nm, and in different ionic strengths using concentrated KCl solutions in the temperature range of 20–90°C. Chemometrics analysis of the spectral data gave a dimerization constant, individual spectra of the monomer and dimer forms of the dye molecule. The quantitative analysis of the data of the undefined mixture was carried out by simultaneous resolution of the overlapping spectral bands in the whole set of absorption spectra. The dimerization constants of MB determined by mathematical deconvolution of the thermometric spectral titration data show dependency on temperature variations. The concentration range of MB was 6.00 × 10?5‐3.00 × 10?4 M. Utilizing the van't Hoff relation, which describes the dependence of the equilibrium constant on temperature, the thermodynamics parameters ΔH° and ΔS° of the aggregation process were determined. The compensation effect was verified by the thermodynamics results of the dimerization process of the dye. 相似文献
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《Analytical letters》2012,45(7):1415-1421
Abstract The coloration reagent - leucomethylene blue, the reduction product of methylene blue, is used to determine the concentration of chlorine dioxide in the presence of Cl2 and anion species such as OCl?, ClO2 ? and ClO3 ?. This simple spectrophotometric method is performed by using the extractant 1,2-dichloroethane at pH 1.3. The linear range of ClO2 measurement extends to 0.95 mgl?1 with a detection limit of 0.02 mgl?1. The presence of chlorine and hypochlorite ion can be masked by oxalic acid. The permissible maximum concentration of ClO2 ? is 2.0 mgl?1, and ClO3 ? anion does not interfere with the measurement. 相似文献
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A study was made on the adsorption kinetics and thermodynamics of methylene blue(MB) and acid blue 80(AB80) onto powder of activated carbon(PAC) prepared by chemical method from dry potato residue(DPR). The PAC was characterized by N2 adsorption-desorption isotherms analysis and scanning electron microscopy. The ma- ximum adsorption capacities of PAC for MB and AB80 at 303 K are 532.19 and 156.22 mg/g, respectively. The results indicate that the adsorption kinetics of the selected dyes on PAC is well-described by the pseudo-second order model. And their thermodynamic data were analyzed via the isotherms of Langmuir, Freundlich, Redlich-Peterson, Toth and Sips, and the thermodynamic parameters were calculated. The results show that PAC is a fast and effective adsorbent for removing the cationic dyes from aqueous solutions. 相似文献