酚醛型吸附树脂在水体系中对苯胺衍生物的吸附性能

N-甲基苯胺;酚醛型吸附树脂在水体系中对苯胺衍生物的吸附性能;N;N-二甲基苯胺     

非水体系中磺酸铜型树脂对苯胺衍生物的配位吸附

研究了磺酸铜型树脂在乙醇和正己烷中对3种芳胺的吸附行为，结果表明：磺酸铜型树脂在乙醇和正己烷中对苯胺，N－甲基苯胺和N，N－二甲基苯胺具有较好的吸附性能，且随着吸附质N原子上取代基的增加，吸附的亲和性逐渐减小，表现出明显的吸附选择性，因此，磺酸铜型树脂有望应用于在非小体系中吸附分离或去除某些难溶于水的天然产物如生物碱等物质。     

酚醛型吸附树脂对水体系中吡啶和N,N-二甲基苯胺的吸附性能研究

研究了酚醛型吸附树脂在水体系中对吡啶和N，N-二甲基苯胺的静态和动态吸附行为．结果表明，在水中树脂对吡啶和N，N-二甲基苯胺的吸附主要以疏水吸附机理进行；吸附吡啶和N．N-二甲基苯胺的初始阶段，即达到38．3～48．9％平衡吸附时，吸附速率数据和半经验速率方程很吻合：酚醛型吸附树脂等温吸附吡啶和N，N-二甲基苯胺的平衡吸附数据符合Langmuir方程，相关系数在0．99以上，酚醛型吸附树脂吸附吡啶和N，N-二甲基苯胺属单分子层吸附：用80％的乙醇溶液作洗脱剂来洗脱吸附吡啶已达饱和的JDW-2树脂，效果是很理想的．在3．6个床体积内洗脱率达91．52％，4．8个床体积内洗脱率达到94．85％。表明酚醛型吸附树脂具有优良的洗脱性能．     

酚醛型吸附树脂在非水体系中对吡啶和N,N-二甲基苯胺的吸附性能研究

研究了酚醛型吸附树脂JDW 2在非水体系中对吡啶和N ,N 二甲基苯胺的静态吸附 .由实验结果推论正己烷中树脂对吡啶和N ,N 二甲基苯胺的吸附是以氢键吸附机理为主进行的 ,JDW 2酚醛型吸附树脂在正己烷中 ,等温吸附吡啶和N ,N 二甲基苯胺的平衡吸附数据符合Langmuir方程 ,相关系数在 0 99以上 ,因此 ,酚醛型吸附树脂在正己烷中吸附吡啶和N ,N 二甲基苯胺属单分子层吸附 ;同时对非水体系中乙醇或乙酸乙酯的含量对树脂吸附吡啶和N ,N 二甲基苯胺的影响进行了研究     

水介质中氢键吸附与疏水吸附协同作用的研究

研究了丙烯酸型树脂(D152)在水、乙醇和正己烷中对苯胺、N-甲基苯胺和N,N-二甲基苯胺的吸附行为.在水中D152树脂对3种吸附质的吸附亲合性随N上甲基数的增加而增大,说明疏水作用是主要的吸附机理,但其吸附焓己超出范德华力的范围而在氢键的键能范围内,故氢键吸附也同时在起作用.在正己烷中,D152树脂对3种吸附质的吸附亲合性随N上甲基数的增加而减小,与水中呈相反的趋势,说明氢键作用是主要的吸附机理.在乙醇中,D152树脂对3种吸附质均无吸附,因为疏水作用和氢键作用均受到的乙醇抑制.在水中,吸附质与树脂间的氢键作用同样受到水的抑制,但氢键吸附却依然存在,说明水介质中氢键吸附和疏水吸附可能存在一种协同作用.在热力学上对水介质中氢键吸附和疏水吸附的协同作用给于合理的解释.     

二苯酮-苯胺体系引发丙烯腈光聚合研究

本文研究了在365nm光照下二苯酮-苯胺体系引发丙烯腈光聚合,在DMF中溶液聚合的动力学方程式为R_p∝[二苯酮]~(0.32)[苯胺]~(0.27[丙烯腈]~(1.1)。不同芳胺引发聚合的速度顺序为:N,N-二甲基苯胺>N-甲基苯胺>苯胺。考察了溶剂极性对聚合的影响,提出质子转移发生在二苯酮和苯胺的激基复合物的紧密离子对状态。聚合物端基分析表明质子转移后产生的两个自由基中主要是苯胺自由基引发聚合。     

非水体系中磺酸铜型树脂对有机碱的配位吸附

研究了磺酸铜型树脂在乙醇、乙酸乙酯和正己烷中对苯胺、N 甲基苯胺和N ,N 二甲基苯胺的吸附规律 ,并与水中的结果相对照 .树脂在正己烷中对苯胺等的吸附量最大 ,在乙醇、乙酸乙脂和水中依次减小 .在4种不同的介质中 ,树脂对苯胺的吸附均表现出相同的吸附选择性 ,即对苯胺的吸附亲合性最大 ,N ,N 二甲基苯胺最小 .在不同的介质中 ,树脂对苯胺的吸附基本符合Freundlich吸附方程 ,并计算了在不同介质中对苯胺吸附的吸附焓 .在水中 ,吸附速率最高 ,在乙醇、乙酸乙酯和正己烷中 ,吸附速率依次降低     

碳酸二甲酯和苯胺胺解反应产物的液相色谱分析

采用气-质联用仪对碳酸二甲酯和苯胺胺解反应合成苯氨基甲酸甲酯的反应体系的副产物N,N-二甲基苯胺进行定性分析,并提出了该反应体系主、副产物的液相色谱的分析方法,以硝基苯为内标物,实现了苯胺、苯氨基甲酸甲酯、N-甲基苯胺、二苯脲及N,N-二甲基苯胺的定量分析,实验结果表明,在一定浓度下,这5种组分与峰高线性良好,回收率在97．8％～102．7％,相对标准偏差小于2．01％。     

煤基合成轻质汽油中三种金属抗爆剂和两种苯胺类化合物的测定

建立了一种采用气质联用法分析煤基合成轻质汽油中三种金属抗爆剂(二茂铁、甲基环戊二烯三羰基锰(MMT)、环戊二烯三羰基锰(CMT)和两种苯胺类化合物(包括苯胺、N,N-二甲基苯胺)的方法。采用强极性INNOWax毛细管色谱柱较好的实现了轻烃和芳烃(C3-C12)组分与三种金属抗爆剂和两种苯胺类化合物的准确分离。采用外标法定量,三种金属抗爆剂在1～50mg·L~(-1)范围内线性关系良好,两种苯胺类化合物在5. 00～250mg·L~(-1)范围内线性关系良好,线性相关系数均达到0. 999,标准样品6次重复性测定的相对标准偏差(RSD)均小于1. 0%,回收率在99. 4%～106. 2%之间,三种金属抗爆剂和两种苯胺类化合物方法测定下限(S/N=3)为0. 016mg·L~(-1)。该方法不需要进行样品前处理,具有操作简单,准确高效的特点,是煤基合成轻质汽油中金属抗爆剂和苯胺类化合物测定的理想分析方法。     

N-甲基苯胺、二苯胺与质子受体相互作用的研究

测量了N-甲基苯胺、二苯胺与一些极性非质子溶剂（B）在CCl_4中的红外光谱，观察到这两种劳胺均与所研究的质子受体发生了氢键交叉缔合作用，并利用光谱数据计算了相应缔合物的形成常数和部分氢键能．结果表明，二苯胺是比N-甲基苯胺更强的质子供体，非质子溶剂的极性、空间效应和不同成键原子对交叉缔合物的稳定性均有一定的影响．还从分子结构对有关结果进行了讨论.     

THE COORDINATION ADSORPTION OF AMINES ON CARBOXYL RESIN IN Cu~(2+) FORM FROM NON-AQUEOUS MEDIUM AND DESORPTION WITH ANHYDROUS ELUANT

The adsorption of aniline, N-methylaniline and N,N-dimethylaniline onto carboxyl resin in Cu~(2+) form from water,ethanol and n-hexane have been studied. The results show that the adsorption affinities from n-hexane are higher than thatfrom water, and nearly zero from ethanol. The separation factors for the adsorption of these three amines from mixed solutionwere also examined. The results of continuous column operations show that the breakthrough capacity of aniline from n-hexane reaches 90 mg/g dry resin in Cu~(2+) form, and the amines adsorbed can be stripped with anhydrous ethanol effectively.Adsorption onto carboxyl resin in Cu~(2+) form from non-aqueous medium and desorption with anhydrous eluant can overcomethe run-off of Cu~(2+) from the resin, and would show potential advantages in the separation of some water-insoluble naturalproducts.     

Excess enthalpies of binary solvent mixtures of 1-butanol and 2-methyl-2-propanol with aniline,N-methylaniline,and N,N-dimethylaniline

The excess molar enthalpies of binary solvent mixtures of 1-butanol and 2-methyl-2-propanol with aniline, N-methylaniline, and N,N-dimethylaniline were measured with a flow microcalorimeter at 40°C. The excess enthalpies are positive for all the systems, and smaller for the mixtures of 1-butanol than the corresponding mixtures of 2-methyl-2-propanol. With respect to the anilines, the values increase in the order aniline < N-methylaniline < N,N-dimethylaniline.     

Ionization of aniline and its N-methyl and N-phenyl substituted derivatives by (free) electron transfer to n-butyl chloride parent radical cations

The electron transfer from aniline and its N-methyl as well as N-phenyl substituted derivatives (N-methylaniline, N,N-dimethylaniline, diphenylamine, triphenylamine) to parent solvent radical cations was studied by electron pulse radiolysis in n-butyl chloride solution. The ionization results in the case of aniline (ArNH2) and the secondary aromatic amines (Ar2NH, Ar(Me)NH) in the synchronous and direct formation of amine radical cations, as well as aminyl radicals, in comparable amounts. Subsequently, ArNH2*+ deprotonates in a delayed reaction with the present nucleophile Cl-, and forms further ArNH*. In contrast, tertiary aromatic amines such as triphenylamine and dimethylaniline yield primarily the corresponding amine radical cations Ar3N*+ or Ar(Me2)N*+, only. The persistent Ar3N*+ forms a charge transfer complex (dimer) with the parent amine molecule, whereas Ar(Me2)N*+ deprotonates to carbon-centered radicals Ar(Me)NCH2*.     

A spectrophotometric study of molecular complexes of 2,3-dicyano-1,4-naphthoquinone

Molecular complexes of 2,3-dicyano-1,4-naphthoquinone with various aromatic anilines were studied spectrophotometrically in dichloromethane solvent at different temperatures. All these complexes show a new broad charge-transfer band in the visible region of the electromagnetic spectrum. All the donors are known to form strong 1:1 complexes with the acceptor and their stoichiometry was unaffected by the variation of temperature over a small interval. The thermodynamic and spectroscopic parameters were evaluated. The order of donor strength followed the sequence: 2,5-dimethylaniline > 2,3-dimethylaniline > N,N-dimethylaniline > p-toluidine > o-toluidine > m-toluidine > N-methylaniline > aniline.     

Modeling synergistic adsorption of phenol/aniline mixtures in the aqueous phase onto porous polymer adsorbents

The adsorption equilibria of phenol and aniline on nonpolar polymer adsorbents (NDA-100, XAD-4, NDA-16 and NDA-1800) were investigated in single- and binary-solute adsorption systems at 313 K. The results showed that all the adsorption isotherms of phenol and aniline on these adsorbents can be well fitted by Freundlich and Langmuir equations, and the experimental uptake of phenol and aniline in all binary-component systems is obviously higher than predicted by the extended Langmuir model, arising presumably from the synergistic effect caused by the laterally acid-base interaction between the adsorbed phenol and aniline molecules. A new model (MELM) was developed to quantitatively describe the synergistic adsorption behavior of phenol/aniline equimolar mixtures in the binary-solute systems and showed a marked improvement in correlating the binary-solute adsorption of phenol and aniline by comparison with the widely used extended Langmuir model. The newly developed model confirms that the synergistic coefficient of one adsorbate is linearly correlated with the adsorbed amount of the other, and the larger average pore size of adsorbent results in the greater synergistic effect of phenol/aniline equimolar mixtures adsorption.     

红外光谱法研究胺与几种溶质的缔合性质

室温下在3800—3000 cm~(-1)内测定了苯脓、N-甲基苯胺与正庚烷、四氯化碳、苯和甲苯二元混合稀溶液的红外光谱, 考察了溶剂对溶质特征红外光谱的影响。测定了苯胺、N-甲基苯胺与吡啶在四氯化碳中作用的红外光谱, 以及苯胺、N-甲基苯胺、三乙胺、三丁胺和吡啶与乙醇在四氯化碳中作用的红外光谱, 计算了相应的交叉缔合常数, 对不同种分子间的相互作用进行了探讨。几种含氮分子与乙醇缔合时, 给予电子的能力按以下次序递增: 苯胺～N-甲基苯胺<三丁胺<吡啶<三乙胺。此外, 还对乙醇+吡啶+氯仿三元体系的特征红外光谱随溶剂比例的变化进行了分析讨论。     

Application of Thin-Layer Chromatography to High-Performance Liquid Chromatographic Separation of Steroidal Hormones and Cephalosporin Antibiotics

Abstract

High-performance liquid chromatographic (HPLC) separation of steroidal hormones and cephalosporin antibiotics was investigated by adsorption chromatography and reversed-phase chromatography, respectively.

Prior to the HPLC separation of these pharmaceuticals, silica gel thin-layer adsorption chromatography of steroidal hormones and reversed-phase thin-layer partition chromatography of cephalosporin antibiotics with chemically bonded dimethylsilyl silica gel were performed in order to obtain suitable HPLC separation systems.

In the separation of steroidal hormones, the same binary mobile phase ratios of TLC did not give satisfactory results in HPLC. For the sharp separation in HPLC, solvent strength in the binary solvent mixture used for TLC had to be decreased.

The difference in solvent strength for efficient separation between TLC and HPLC might be attributed to the fact that in HPLC the solvent elution power acts in an isocratic manner while in TLC it acts in a gradient manner.

On the other hand, a correlation of mobility between TLC and HPLC separation for cephalosporin antibiotics was obtained, and the possibility of direct transfer of chromatographic systems from TLC to HPLC for separation of these antibiotics was confirmed.     

Comprehensive separation of a wide variety of compounds from olive leaves by counter-current chromatography with three-phase solvent system

The three-phase solvent system counter-current chromatography has been of great research interest, because it can separate compounds with a wide range of polarity. The solvent system of n-hexane/methyl tert-butyl ether/acetonitrile/water (5:5:7:5, v/v) was used for counter-current chromatographic comprehensive separation of olive leaves. The study adopted the normal elution mode. The middle phase and the lower phase (at a volume ratio of 7:3) were pumped into the column simultaneously, followed by eluting with the upper, middle, and lower phases in sequence. The retention rate of the stationary phase measured by the experiment was 73.5%. The upper phase was used to elute the nonpolar compounds, then the mobile phase was switched to the middle phase to elute the moderately hydrophobic compounds, finally, the polar compounds were eluted by the lower phase remaining in the chromatographic column. This method successfully separated eight compounds in one step within 270 min and five compounds were identified. The logP values of these five compounds were 7.44, 7.86, 4.16, −0.11, and 0.96, respectively, covering a wide range of polarities. The present study demonstrated that the three-phase solvent has a strong extraction capacity for ingredients from extremely hydrophilic compounds to extremely hydrophobic compounds.     

Capillary electrochromatography with monolithic stationary phases. 4. Preparation of neutral stearyl-acrylate monoliths and their evaluation in capillary electrochromatography of neutral and charged small species as well as peptides and proteins

A neutral, nonpolar monolithic capillary column having a relatively strong electroosmotic flow (EOF) yet free of electrostatic interactions with charged solutes was developed for the reversed-phase capillary electrochromatography (RP-CEC) of neutral and charged species including peptides and proteins. The neutral nonpolar monolith is based on the in situ polymerization of pentaerythritol diacrylate monostearate (PEDAS) in a ternary porogenic solvent composed of cyclohexanol, ethylene glycol, and water. PEDAS plays the role of both the cross-linker and the ligand provider, generating a macroporous nonpolar monolith having C17 chains as the chromatographic ligands. Despite the fact that the neutral PEDAS monolith is devoid of fixed charges, the monolithic capillary columns exhibited a relatively strong EOF due to the ability of PEDAS to adsorb sufficient amounts of electrolyte ions from the mobile phase. The adsorbed ions imparted the neutral PEDAS monolith the zeta potential necessary to support the EOF required for mass transport across the monolithic column. The absence of fixed charges on the surface of the neutral PEDAS monolith and in turn the adsorption sites for electrostatic attraction of charged solutes allowed the rapid and efficient separations of proteins and peptides at pH 7.0, with an average plate number of 255,000 and 121,000 plates/m, respectively. To the best of our knowledge, this constitutes the first report on the separation of proteins at neutral pH by RP-CEC using a neutral monolithic column.