毛细管区带电泳对羟基苯甲酸三种异构体的分离研究

考察了邻羟基苯甲酸、间羟基苯甲酸和对羟基苯甲酸在毛细管区带电泳分离时的行为。研究了缓冲液pH、浓度和分离电压对三种羟基苯甲酸异构体分离的影响,结果表明在10 mmol/L Na2HPO4缓冲体系(pH 10.15),运行电压25kV,实验温度25℃的分离条件下,采取压力进样(3.4 kPa×3 s),检测波长210nm;3种异构体在7 min内获得基线分离。邻羟基苯甲酸、间羟基苯甲酸、对羟基苯甲酸在2~100μg/mL范围内,峰面积与质量浓度具有较好的线性关系,检出限分别是0.96,1.27和1.07μg/mL。     

羟基苯甲酸的3种异构体的毛细管区带电泳分离研究

 采用十六烷基三甲基溴化铵 (CTAB)为电渗流改性剂 ,考察了邻羟基苯甲酸、间羟基苯甲酸和对羟基苯甲酸在高效毛细管区带电泳模式下的分离行为 ,研究了缓冲液的pH和添加剂甲醇的用量对这 3种同分异构体的分离、峰形和出峰顺序的影响 ,并据此优化了这 3种异构体的分离条件。     

羟基苯甲酸异构体的毛细管区带电泳分离及阿司匹林片剂中邻羟基苯甲酸的测定

1引言邻羟基苯甲酸主要用于医药工业合成阿司匹林。我国药典(2005版)规定片剂中的含量不能超过0.3%。本实验以阳离子表面活性剂十六烷基三甲基溴化铵(CTMAB)作电渗流改性剂,乙腈作有机添加剂,利用毛细管区带电泳-二极管阵列检测器技术实现了邻羟基苯甲酸与间羟基苯甲酸和对羟基     

反相高效液相色谱法快速测定大麦籽粒中13种酚酸类化合物

建立了快速测定大麦籽粒中13种酚酸类化合物(没食子酸、原儿茶酸、绿原酸、对羟基苯甲酸、咖啡酸、香草酸、丁香酸、间羟基苯甲酸、对香豆酸、阿魏酸、藜芦酸、邻香豆酸和水杨酸)的反相高效液相色谱方法.采用SUPELCOAscentis(@) C18色谱柱(150 mm×4.6 mm,5μm)分离,流动相为甲醇-0.1％甲酸水溶...     

蒽与苯甲酸及其衍生物之间的作用机理研究

用紫外差光谱、红外光谱法和荧光猝灭法研究了典型多环芳烃蒽与苯甲酸及其羟基取代衍生物邻羟基苯甲酸和对羟基苯甲酸之间的作用机理。实验结果表明,在此芳香羧酸与蒽之间存在定向的、特异性的作用,其作用方式受到反应物结构和环境酸度的影响。对苯甲酸和邻羟基苯甲酸而言,当pH<pKa时,二者之间以蒽离域大π电子与羧基质子之间的π-H氢键作用为主,pH>pKa时,π-π电子给体受体作用逐渐成为主要结合方式。邻位羟基的存在使得苯甲酸与蒽的作用强度明显降低。对羟基苯甲酸特殊的D-π-A型分子结构使得它在溶液中形成平面多分子聚集体,这种多分子聚集体的生成使得对羟基苯甲酸与蒽的结合方式不随酸度变化,在pH2.0~10.0的范围内均以π-π电子给体受体作用相结合,且结合强度大于苯甲酸和邻羟基苯甲酸。     

苯乙烯绿色氧化合成苯甲酸的机理研究

本文报道了用GC-MS跟踪了双氧水氧化苯乙烯为苯甲酸的全过程,研究结果发现4种主要物质苯乙烯、1-苯基邻二醇、羟基苯乙酮及苯甲酸含量随反应时间的变化关系,从而提出了其主要氧化机理可能为:苯乙烯首先经过环氧化反应,水解生成1-苯基邻二醇,然后1-苯基邻二醇氧化为羟基苯乙酮,羟基苯乙酮最后氧化为苯甲酸。     

模板分子中作用基团的数目及位置对印迹聚合物印迹效应的影响

为了研究模板分子中作用基团的数目和位置对印迹聚合物印迹效应的影响, 分别以含有羟基数目和位置不同的羟基苯甲酸化合物3,4,5-三羟基苯甲酸(3,4,5-THBA), 3,4-二羟基苯甲酸(3,4-DHBA), 2,4-二羟基苯甲酸(2,4-DHBA)和3-羟基苯甲酸(3-HBA)为模板分子, 以丙烯酰胺为功能单体, 乙二醇二甲基丙烯酸酯为交联剂和乙腈(MeCN)为致孔剂, 采用非共价本体聚合方法制备了对应的印迹聚合物, 用色谱法评价了其分子识别性能. 结果表明, 制备的印迹聚合物对相应的模板分子均具有印迹效应, 在流动相H₂O/MeCN(体积比1/99)中, 各印迹聚合物对相应的模板分子3,4,5-THBA, 3,4-DHBA, 2,4-DHBA和3-HBA的印迹因子分别为5.51, 5.55, 2.60和2.03. 通过与同样条件下制备的龙胆酸(GA)、水杨酸(SA)和对-羟基苯甲酸(4-HBA)印迹聚合物对其模板分子印迹效应的比较发现, 模板分子中作用基团数目越多, 印迹效率越高; 模板分子中作用基团-COOH和-OH的相对位置对印迹效率影响很大, 当-COOH和-OH在苯环上处于对位时的印迹效率, 高于其处于间位的印迹效率; 当-COOH和-OH在苯环上处于邻位时, 由于形成分子内氢键会降低其印迹效率. 实验还发现, 3,4-DHBA的印迹聚合物可以实现其结构类似物3,4,5-THBA和2,4-DHBA的基线分离, 为生物活性组分3,4,5-THBA的分离和测定提供了依据.     

双峰倍增配平法用于同步、导数-同步荧光法同时测定邻羟基苯甲酸和间羟基苯甲酸

邻羟基苯甲酸（ｏＨＢＡ）和间羟基苯甲酸（ｍＨＢＡ）荧光光谱严重重叠，同步及导数技术虽使选择性有所改善，但仍不能完全分辨开重叠谱。用双峰倍增配平计算法结合同步、一阶导数－同步荧光法对双组分体系（邻羟基苯甲酸／间羟基苯甲酸，ｐＨ１２介质）同时测定。结合计算的两种测定方法精密度、回收率和不同组分间浓度比范围均优于一阶导数－同步荧光法。     

胶束电动毛细管色谱法测定板蓝根中苯甲酸、水杨酸和邻氨基苯甲酸

采用胶束电动毛细管色谱法对板蓝根中芳香酸类化合物苯甲酸、水杨酸和邻氨基苯甲酸进行了分离测定。电泳介质(pH 9.8)为20 mmol.L-1硼砂、30 mmol.L-1十二烷基硫酸钠、2 mmol.L-1β-环糊精和4%(体积分数)甲醇组成的混合溶液,以对-羟基苯甲酸为内标,分离电压为16 kV,检测波长为250 nm。在优化的试验条件下,苯甲酸、水杨酸和邻氨基苯甲酸的线性范围分别为40～240 mg.L-1,64～320 mg.L-1和40～400 mg.L-1,检出限(3S/N)依次为0.64,1.08,1.36 mg.L-1。应用此方法分析了板蓝根样品,测定回收率在93.3%～104.2%之间。     

双峰倍增配平法用于同步,导数—同步荧光法同时测定邻羟基苯甲酸和间 …

邻羟基苯甲酸（ｏ－ＨＢＡ）和间羟基苯甲酸（ｍ－ＨＢＡ）荧光光谱严重重叠，同步及导数技术虽使选择性有所改善，但仍不能完全分辨开重叠谱。用双峰倍配平计算法结合同步，一阶导数－同步荧光法对双组分体系（邻羟基苯甲酸／间羟基苯甲酸，ｐＨ１２介质）同时测定，结合计算的两种测定方法精密度，回收率和不同组分间浓度比范围均优于一阶导数－同步荧光法。     

Synthesis and identification of dinitro- and diaminoterephthalic acid

Dinitroterephthalic acid(DNTPA) and diaminoterephthalic acid(DATPA) were prepared in 85%and 75%yields,respectively. These compounds were characterized by using FTIR and ~1HNMR.DATPA can be used as a monomer for the preparation of polyesters and polyamides.     

离子色谱法测定水中4种有机酸

建立了水样中甲酸、乙酸、丙烯酸和甲基丙烯酸的离子色谱测定方法,采用IonPac AS11-HC阴离子分离柱,以KOH为淋洗液,采用浓度梯度洗脱,可同时测定上述4种有机酸。方法对实际水样中甲酸、乙酸、丙烯酸和甲基丙烯酸的平均加标回收率在80.2%~103.3%,相对标准偏差在5.8%之内,检出限分别为:0.005,0.003,0.005和0.004mg/L;定量下限分别为:0.020,0.012,0.020和0.016mg/L。方法准确、简便、环保,能够满足实际水样的测定需要,且水样中常见的阴离子不会对目标污染物的测定产生影响。     

Surface Functionalization of Magnetite Nanoparticles with Sulfonic Acid and Heteropoly Acid: Efficient Magnetically Recoverable Solid Acid Catalysts

New magnetically recoverable solid acid catalysts for acid‐catalyzed reactions were designed via the surface chemical functionalization of silica‐coated magnetite nanoparticles (SCMNPs) with sulfonic acid groups. First, the SCMNPs were covalently functionalized with 3‐aminopropyl groups to achieve Amp‐SCMNPs. Then, reaction of the Amp‐SCMNPs with 1,4‐butane sultone followed by acidification with phosphotungstic acid (HPW) or diluted sulfuric acid produced magnetically recoverable solid acid catalysts, HPW‐ampsul‐SCMNPs and H‐ampsul‐SCMNPs, respectively. Both catalysts were characterized by various physicochemical analyses such as Fourier transform infrared (FT‐IR) and inductively coupled plasma‐optical emission (ICP‐OES) spectroscopies, vibrating sample magnetometry (VSM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X‐ray diffraction (XRD), and energy‐dispersive X‐ray (EDX) analyses. Finally, the catalytic activities of the prepared catalysts were examined in the esterification of acetic acid with butanol and acetalization of benzaldehyde with ethylene glycol. Excellent catalytic efficiencies were obtained in both cases. The catalysts were consecutively recovered and reused five times without significant loss of their activities.     

Efficient formation of novel and versatile building blocks from mucohalic acids: new substitute for tetronic acid and γ-alkylidenebutenolide

Novel and useful building blocks were synthesized efficiently by DABCO mediated highly selective dehalogenation of Knoevenagel aldol adducts of mucochloric acid and mucobromic acid. These new compounds were found to undergo palladium catalyzed C-C bond forming reactions (Suzuki and Sonogashira cross-coupling) in high yields.     

Anthranilic acid derivatives from Inula japonica

Three new anthranilic acid derivatives, N-heneicosanoylanthranilic acid （1b）, N-tricosanoylanthranilic acid （1d）, N-tetracosanoylanthranilic acid （1e）, and two known N-arachidylanthranilic acid （1a） and N-docosanoylanthranilic acid （1c） were isolated from the aerial parts of lnula japonica Thunb. Their structures were established by spectroscopic and chemical methods.     

Determination of trace anions in concentrated weak acids by ion chromatography

Ion-exclusion chromatography (ICE) followed by ion chromatography (IC) was used for the determination of trace anionic contaminants in concentrated weak acids. The ICE separation was used as a pretreatment step to isolate the contaminant anions of strong acids from the excess of matrix ions. Then a fraction containing the analyte ions was separated using IC with suppressed conductivity detection. Microbore–ion-exchange columns were chosen to address the increased purity requirements for use of these concentrated acids in semiconductor applications. The chromatographic conditions were optimized for determining trace chloride, sulfate, phosphate, and nitrate in concentrated 24.5% (v/v) hydrofluoric acid; trace chloride, sulfate, and nitrate in concentrated 85% (w/w) phosphoric acid and trace chloride and sulfate in concentrated 0.7% (v/v) glycolic acid. Method detection limits for the anions of interest were below 100 μg/l.     

Ionic Complexes of Polyacids and Cationic Surfactants

Comb-like ionic complexes were prepared from polyuronic acids (pectinic and alginic acids) and alkyltrimethylammonium surfactants bearing linear alkyl chains with 18, 20 and 22 carbon atoms. In the condensed state, these complexes were able to self-assemble in ordered structures which were thermally stable up to ∼200 °C. The complexes were analysed by DSC and WAXS/SAXS and compared to their analogous made from poly(γ-glutamic acid). They all adopt a biphasic layered structure in which the main chain and the alkyl side chain alternate with a nanometric periodicity. Alkyl side chains were partially crystallized in these complexes and they show reversible melting at temperatures within the 60-80 °C range depending on the length of the polymethylene segment.     

共轭亚油酸制备方法的研究进展

依据反应机理和原料对具有生理活性的共轭亚油酸的制备与纯化方法进行了综述。详细讨论了共轭多烯酸(尤其是共轭亚油酸)的合成方法的研究进展，依据目标产物的收率、纯度及成本对合成或制备方法进行了比较和评价。     

Synthesis and study of (2S,4S)-4-arylamino-2-carboxy-5-pyrrolidones

(2S,4S)-4-Arylamino-2-carboxy-5-pyrrolidones were prepared by hydrolysis of dimethyl (2S,4S)-4-arylamino-N-phthaloylglutamates. The protonation constants of the arylamino group in the synthesized compounds were determined. The pyrrolidone ring is stable in acidic or neutral solutions. The relative stability of the pyrrolidone ring in alkaline solutions was studied by IR spectroscopy.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2087–2090, December, 1993.