5—溴水杨基荧光酮—溴化十六烷基三甲铵荧光熄灭法测定微量？…

本文报道了在溴化十六烷基三甲铵（ＣＴＭＡＢ）存在下,以５－溴水杨基荧光酮（５－ＢrＳＡＦ）作为荧光试剂,用荧光熄灭法测定微量钼的新方法。详细研究了各种条件实验。 反应了适宜酸度范围为０．０８－０．２４ｍｏｌ．Ｌ＾－１ＨＣ１,钼含量在０－４．０ｕｇ／２５ｍＬ范围内呈线性关系,配合物的组成比为Ｍo（Ⅳ）：５－ＢrＳＡＦ：ＣＴＭＡＢ＝１：２：２,激发波长为３６５ｎｍ,发射波长为５２５ｎｍ。方法灵敏度高,检出     

5-溴水杨基荧光酮-溴化十六烷基三甲铵荧光熄灭法测定微量钼的研究

本文报道了在溴化十六烷基三甲铵（ＣＴＭＡＢ）存在下,以５－溴水杨基荧光酮（５－ＢｒＳＡＦ）作为荧光试剂,用荧光熄灭法测定微量钼的新方法。详细研究了各种条件实验。反应的适宜酸度范围为 ０．０８－０．２４ｍ ｏｌ·Ｌ－ １ ＨＣｌ,钼含量在０－ ４．０μｇ／２５ｍ Ｌ范围内呈线性关系,配合物的组成比为Ｍｏ（Ⅵ）∶５－ＢｒＳＡＦ∶ＣＴＭＡＢ＝ １∶２∶２,激发波长为３６５ｎｍ ,发射波长为５２５ｎｍ 。方法灵敏度高,检出限为２．０μｇ／Ｌ。用于样品中微量钼的测定,结果令人满意。     

SPAPT-CPB-AS光度法测定阴离子表面活性剂

在ＮａＯＨ介质中,新试剂１－（４－磺酸基苯基）－３－「４－（苯基偶氮）苯基」三氮烯（ＳＰＡＰＴ）和溴化十六烷基吡啶（ＣＰＢ）与阴离子表面活性剂（ＡＳ）发生显色反应,形成三元配合物。利用ＳＰＡＰＴ－ＣＰＢ－ＡＳ显色体系。研究了光度法有离子表面活性剂。最大吸收波长５９０ｎｍ,测定十二基苯磺酸钠（ＤＢＯＳＯ３Ｎａ）、十二烷基磺酸钠（ＤＯＳＯ３Ｎａ）、十二烷基硫酸钠（ＤＳＯ４Ｎａ）的表观摩尔吸光系数分别为     

表面活性剂存在下借反应温差同时测定混合物中钯和铑

研究了Ｐｄ（Ⅱ）、Ｒｈ（Ⅲ）在乙醇、各种表面活性剂分别存在下与２－（３，５－二溴－２－吡啶偶氮）－５－二乙氨基酚（３，５－ｄｉＢｒ－ＰＡＤＡＰ）的显色反应，发现溴化十六烷基吡啶（ＣＰＢ）存在下，于ｐＨ５．０～６．８ＨＡｃ－ＮａＡｃ缓冲介质中，Ｐｄ（Ⅱ）能于室温（ＲＴ）显色，其配合物经沸水浴加热（ＢＴ）后吸光度仅略有增加；而Ｒｈ（Ⅲ）必须在加热下才反应显色，，测Ｒｈ灵敏度高于已有文献值。测定了上述配合物组成，借此两显色反应所需温度差异，建立了同时测定Ｐｄ和Ｒｈ的速差动力学分析方法。该法简便灵敏，用于含Ｐｄ和Ｒｈ的合成混合物及催化剂分析，结果较满意。     

5‘—硝基—水杨基荧光酮—溴化十六烷基三甲胺荧光猝灭法测定？…

本文基于Ｚｒ（Ⅳ）５‘－硝基－水杨基荧光酮－溴化十六烷基三甲铵（ＣＴＭＡＢ）体系的荧光猝灭效应,提出一种测定微量锆的新荧光分析方法。在０．８－１．２--ｍｏｌ／Ｌ的Ｈ２ＳＯ４介质中,ＣＴＭＡＢ存在下,锆与５’－Ｎ－ＳＡＦ生成组成比为１：４的橙红色络合物。     

多波长线性回归分光光度法同时测定催化剂中钨和钼

以水杨基荧光酮（ＳＡＦ）－溴代十六烷基三甲铵（ＣＴＭＡＢ）为显色体系，详细考查了测定条件。采用多波长线性回归分光光度法同时测定了Ｗ－Ｍｏ－Ｎｉ／Ａｌ２Ｏ３加氢催化剂中的钨和钼。相对标准偏差小于１．６％，合成样品回收率９４．０％－１０６．４％。测定结果与比色法（分别测定）及Ｘ－射线荧光光谱法相吻合。     

5′-硝基水杨基荧光酮双波长标准加入分光光度法同时测定锗和钼

在０．３～０．９ｍｏｌ／Ｌ硫酸介质中，在溴化十六烷基三甲铵（ＣＴＭＡＢ）存在下，５′－硝基水杨基荧光酮（５′－ＮＳＦ）与锗（Ⅳ）和钼（Ⅵ）形成最大吸收波长分别为５１３和５３３ｎｍ的红色配合物，其吸收光谱严重重叠。基于此，本文采用双波长标准加入法对该混合物的显色体系进行研究，建立了同时分光光度测定锗和钼的新方法，并与等吸收双波长法作了比较。     

新试剂1-(2-羟基苯基)-3-[4-(苯基偶氮)苯基]-三氮烯的合成及与溴化十六烷基三甲铵的显色反应

合成了新试剂１－（２－羟基苯基）－３－［４－（苯基偶氮）苯基］－三氮烯（ＨＰＡＰＴ）,在氢氧化钠碱性介质中,该试剂与溴化十六烷基三甲铵（ＣＴＭＡＢ）形成１∶３的紫红色离子缔合物。λｍａｘ位于５６５ｎｍ,表观摩尔吸光系数为１．５９×１０４Ｌ·ｍｏｌ－１·ｃｍ－１,ＣＴＭＡＢ含量在３—２９．１６ｍｇ·Ｌ－１范围内符合比耳定律。测定了显色体系ＣＴＭＡＢ的临界胶束浓度是１．５０×１０－４ｍｏｌ·Ｌ－１。     

5′-硝基-水杨基荧光酮-溴化十六烷基 三甲胺荧光猝灭法测定微量锆

本文基于Ｚｒ（Ⅳ）－５′－硝基－水杨基荧光酮（５′－Ｎ－ＳＡＦ）－溴化十六烷基三甲铵（ＣＴＭＡＢ）体系的荧光猝灭效应,提出一种测定微量锆的新荧光分析方法。在０．８～１．２ｍｏｌ／Ｌ的Ｈ２ＳＯ４介质中,在ＣＴＭＡＢ存在下,锆与５－Ｎ－ＳＡＦ生成组成比为１∶４的橙红色络合物。该体系存在两个激发峰,其激发波长分别为λｅｘ１＝４７５ｎｍ,λｅｘ２＝５０５ｎｍ,发射波长λｅｍ＝５２５ｎｍ。锆（Ⅳ）浓度在２．０～８０μｇ／Ｌ呈良好线性关系,检出限为２．０μｇ／Ｌ。本法灵敏度高,选择性好,用于铝合金中微量锆的测定,获得满意结果。     

阳离子表面活性剂与溴酚红的显色反应及其分析应用

研究了阳离子表面活性剂 (CSAA)溴化十六烷基三甲铵 (CTAB)、溴化十六烷基吡啶 (CPB)在水溶液中与溴酚红 (BPR)的显色反应。发现在pH 5 0～ 6 0范围内 ,CSAA单体与BPR形成离子缔合物(缔合比为 3∶2 ) ,可用于微量CSAA及CSAA的临界胶束浓度 (CMC)的测定。本文还研究了显色反应的适宜条件、分析特征 ,并讨论了反应机理     

Molecular ordering of mixed surfactants in mesoporous silicas: a solid-state NMR study

The use of mixed surfactants in the synthesis of mesoporous silica nanoparticles (MSNs) is of importance in the context of adjusting pore structures, sizes and morphologies. In the present study, the arrangement of molecules in micelles produced from a mixture of two surfactants, cetyltrimethylammonium bromide (CTAB) and cetylpyridinium bromide (CPB) was detailed by solid-state NMR spectroscopy. Proximities of methyl protons in the trimethylammonium headgroup of CTAB and protons in the pyridinium headgroup of CPB were observed under fast magic angle spinning (MAS) by (1)H-(1)H double quantum (DQ) MAS NMR and NOESY. This result suggested that CTAB and CPB co-exist in the pores without forming significant monocomponent domain structures. (1)H-(29)Si heteronuclear correlation (HETCOR) NMR showed that protons in the headgroups of CTAB are in closer proximity to the silica surface than those in the CPB headgroups. The structural information obtained in this investigation leads to better understanding of the mechanisms of self-assembly and their role in determining the structure and morphology of mesoporous materials.     

胶束体系中荧光素与四溴荧光素间能量转移条件及模型研究

研究了阳离子表面活性剂(CSAA)在水溶液中与阴离子酸性染料四溴荧光素(TBF)的荧光反应,发现当CSAA单体与TBF形成离子缔合物时,TBF的荧光发生猝灭,而CSAA胶束与TBF作用又会产生一个新的、更强的荧光。进而研究了阳离子表面活性剂CTMAB及CPB胶束体系中酸性阴离子荧光染料荧光素与四溴荧光素间的能量转移条件。表明只有在带相反电荷的CSAA形成的胶束中,阴离子染料间的能量转移才可能发生,在2/3临界胶束浓度(CMC)时能量转移效率达到最大。并推测了胶束体系中染料间能量转移模型及染料间能量转移的一般规律。     

Films made of cellulose nanofibrils: surface modification by adsorption of a cationic surfactant and characterization by computer-assisted electron microscopy

Films made of nanofibrils were modified by adsorption of a cationic surfactant directly on the film surfaces. The nanofibrils were prepared by 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO)-mediated oxidation and mechanical fibrillation, and were relatively homogeneous in size. The average nanofibril diameter and surface porosity was quantified based on computer-assisted field-emission scanning electron microscopy (FE-SEM). The cationic surfactant used in the adsorption was n-hexadecyl trimethylammonium bromide (cetyltrimethylammonium bromide, CTAB). The adsorption of CTAB was confirmed by Fourier transform infrared (FTIR) spectroscopy and high-resolution transmission electron microscopy (HRTEM) analyses. It was shown that the adsorbed layer of CTAB increased the hydrophobicity, without affecting the tensile index significantly. This capability, combined with the antiseptic properties of CTAB, may be a major advantage for several applications.     

β-Cyclodextrin Effect on Micellization of Cetyltrimethyl ammonium Bromide in Aqueous Solution. Probed by Dual Fluorescence of Sodium P-Dimethylaminobenzoate

Effect of p-cyclodextrin (β-CD) on micellization of cetyltrimethylammonium bromide (CTAB) in aqueous solution was investigated by twisted intramolecular charge transfer (TICT) dual fluorescence of sodium p-dimethylaminobenzoate (SDMAB). It was shown that β-CD induces the micellization of CTAB and the aggregation of CTAB below CMC as well. A reduced charge density at CTAB micelle interface in the presence of β-CD, due to the incorporation of 1:1 CTAB-β-CD inclusion complex in micelle, was concluded to be the reason for β-CD induced micellization of CTAB.     

The molecular structures, vibrational spectroscopies (FT-IR and Raman) and quantum chemical calculations of n-alkyltrimethylammonium bromides

The FT-IR and micro-Raman spectra of three n-alkyltrimethylammonium bromides (dodecyltrimethylammonium bromide (DTAB), tetradecyltrimethylammonium bromide (TTAB) and hexadecyl(cetyl)trimethylammonium bromide (CTAB)) in powder form were recorded in the regions 4000–550 cm^?1 and 3200–300 cm^?1, respectively. The optimized geometries and vibrational frequencies of DTAB, TTAB and CTAB have been carried out with ab initio Hartree-Fock (HF) and density functional theory method B3LYP calculations with the 6–31 G (d, p) basis set in the ground state. The comparison of the observed fundamental vibrational frequencies and calculated results for the fundamental vibrational frequencies of DTAB, TTAB and CTAB indicate that the scaled B3LYP method is superior compared to the scaled HF method.     

TX-100和CTAB交换动力学的核磁共振研究

运用核磁共振(NMR)方法分别测定了表面活性剂辛基苯聚氧乙烯醚(TX-100)和十六烷基三甲溴化铵(CTAB)在不同温度下的临界胶束浓度.阐述了应用1D NMR线型分析方法对表面活性剂快交换体系平均停留时间的定量测量.实验测量了TX-100和CTAB胶束溶液中表面活性剂分子在不同温度下的平均停留时间.结果显示,平均停留时间随温度的增加逐渐减小,说明TX-100和CTAB分子进出胶束的速率随温度的增加逐渐加快.利用阿伦尼乌斯公式拟合,获得了TX-100和CTAB的表观交换活化能,TX-100的表观交换活化能为17.6 k J/mol,CTAB的表观交换活化能为75.3 k J/mol.对TX-100和CTAB平均停留时间和表观交换活化能进行分析,得出平均停留时间和表观交换活化能与分子结构的关系:表观交换活化能反映的是疏水相互作用和静电斥力的大小;而平均停留时间不仅受活化能的影响,还与分子结构有关.     

High Temperature Seedless Synthesis of Au NRs Using BDAC/CTAB Co-surfactant

采用等离子体活化技术制备了一种新型Ni/γ-Al2O3催化剂用于CO2重整CH4反应. 等离子体强化制备的催化剂表现出较高的反应活性和较好的抗积碳能力. 为了达到相同CH4转化率,常规焙烧的催化剂需要比等离子体处理的催化剂高出50 °C 的反应温度. 反应结束后,等离子体处理催化剂的失活率仅为1.7%,而常规催化剂上的失活率为15.2%。通过对催化剂进行BET、H2-TPR、XRD、CO2-TPD和TG等表征分析,结果表明等离子体增强制备方法使催化剂的平均孔直径减小,比表面积增加;催化剂的还原性,镍物种的分散度和催化剂对CO2的吸附量都有显著的提高.     

Improved optical performance of CdO films prepared with CTAB as surfactant

The influence of surfactant cetyl trimethyl ammonium bromide (CTAB) on structural, morphological and optical properties of CdO films has been investigated. Five series of CdO films were successfully prepared by successive ionic layer adsorption and reaction method with the assistance of CTAB. These CdO films were characterized by X-ray diffraction, scanning electron microscopy and UV–vis spectroscopy. The CTAB caused in a decrease in crystallite size but an increase in the optical band gap of CdO films. From the optical investigations, it was observed that the transmittance of the pure film was about 2% and it increased dramatically to 37% for 2?M% CTAB added CdO films at the wavelength of 1100?nm. The results show that the amount of CTAB played an important role in determining the physical properties of the CdO nanostructures.     

纺锤形β-FeOOH的形成过程研究

应用透射电镜技术观察了FeCl3 水解形成纺锤形 β FeOOH过程中颗粒的形貌变化 ,发现纺锤形β FeOOH颗粒是由针形初级粒子沿长轴聚集长大形成的 .加入表面活性剂十六烷基三甲基溴化铵 (CTAB)后 ,β FeOOH 形成机制发生改变 ,β FeOOH晶核通过扩散过程而长成纺锤形颗粒 .CTAB的存在使 β FeOOH颗粒变小而且粒径更均匀 .改变反应条件包括起始FeCl3 的浓度、陈化温度 ,得到了纺锤形和针形、不同轴比的单分散β FeOOH .     

Small angle neutron scattering studies of mixed micelles of sodium cumene sulphonate with cetyl trimethylammonium bromide and sodium dodecyl sulphate

The aqueous solutions of sodium cumene sulphonate (NaCS) and its mixtures with each of cetyl trimethylammonium bromide (CTAB) and sodium dodecyl sulphate (SDS) are characterized by small angle neutron scattering (SANS). NaCS when added to CTAB solution leads to the formation of long rod-shaped micelles with a dramatic increase in the CTAB aggregation number. Its addition to SDS on the other hand results in the formation of smaller mixed micelles where part of SDS molecules in the micelle is replaced by NaCS molecules.