EFFECT OF pH ON THE ADSORPTION OFp-AMINOBENZOIC ACID ON POLYSTYRENE-BASED ADSORBENTS

In the present study the adsorptive properties of p-aminobenzoic acid with hypercrosslinked and multi-functional polymeric adsorbents at different solution pHs were systematically investigated in accordance with the particular physicochemical characteristics of the aromatic amphoteric compound involving both Lewis acid and Lewis base functional groups. It was found that the equilibrium adsorption data of the three polymeric adsorbents fitted well in the Langmuir and Freundlich isotherm equations. Studies at various pH levels indicate that the capacity of the adsorbents for adsorption of the ionic forms of adsorbate is less than that for the corresponding neutral species. At pH 3.78, the adsorption capacities of the three adsorbents are the highest. Whereas the adsorption property of multi-functional polymeric adsorbent NJ-99 is the largest, which may be attributed to the strong hydrogen-bonding interaction between the amino groups on the resin and the carboxyl group of p-aminobenzoic acid. The trend of the adsorption capacities of the three adsorbents towards p-aminobenzoic acid with the solution pH is in accord with the dissociation curve of the neutral molecular p-aminobenzoic acid. The adsorption forces include π-π interaction, hydrogen-bonding interaction and electrostatic attraction or repulsion when there exist the molecular and ionic adsorbing species at different pHs in aqueous solution.

Distribution Behavior of Aminobenzoic Acid by Extraction with Di(2-ethylhexyl)phosphoric Acid

A series of extraction equilibrium experiments for aminobenzoic acid with di(2-ethylhexyl)phosphoric acid (D2EHPA) dissolved in n-octane or 1-octanol was carried out. The effects of aminobenzoic acid concentration,D2EHPA concentration and pH on the distribution ratio were discussed in detail. The infrared spectra of the organic phase loaded with solute illustrated that pH had little effect on the structure of the complex formed. There proceed ion association and cation-exchange.reaction in the extraction. An expression of the equilibrium distribution was proposed.

Substituent effect on spectral and antimicrobial activity of Schiff bases derived from aminobenzoic acids

The dependence of electronic absorption spectra antimicrobial property on the substituent position was investigated using three Schiff bases derived from salicylaldehyde and isomeric aminobenzoic acids in three solvents of different polarities. The absorption maxima in all three solvents exhibited dependence on the position of substituent with the absorption maxima undergoing a red shift as solvent polarity increased. The in vitro antibacterial activity of the compounds against some clinically important bacteria namely Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853), Staphylococcus aureus (ATCC 25923), Enterococcus feacalis (ATCC 29212) was determined in N,N”-dimethylformamide and 1,4-dioxane using the agar dilution method. The results revealed that the ortho and meta substituted Schiff bases exhibited better antimicrobial activity in the non-polar solvent.

Syntheses and Crystal Structures of Cobalt(II) and Nickel(II) Coordination Polymers with 3-Aminobenzoic Acid Ligand

Two coordination polymers, [ML2]n （M = Co （1）, Ni （2）, L = 3-aminobenzoic acid anion）, were synthesized by hydrothermal reaction, and their crystal structures were determined by X-ray diffraction analysis. Both compounds crystallize in monoclinic, space group P21/n with a = 8.8029（8）, b = 4.5297（4）, c = 15.2002（14）A°, β= 105.6280（10）°, C14H12CoN2O4, Mr= 331.19, Z= 2, V = 583.69（9）A°^3 Dc= 1.884 g/cm^3,μ=1.490 mm^-1, F（000） = 338, R = 0.0234 and wR = 0.0679 for 1337 observed reflections （I 〉 2σ（I）） for 1, and a = 8.7501（7）, b = 4.5191（4）, c = 15.1448（12） A°,β = 105.7730（10）° C14H12 NiN2O4, Mr = 330.97, Z = 2, V = 576.31（8）A°3, Dc = 1.907 g/cm^3,μ = 1.703 mm^-1, F（000） = 340, R = 0.0206 and wR = 0.0572 for 1209 observed reflections （I 〉 2σ（I）） for 2. In the title complexes, the M （Ⅱ） ion presents an octahedral geometry with four oxygen donors in the equatorial positions and two nitrogen donors in the axial positions. Each of the complexes has a two-dimensional network structure that is formed by the bridging of the ligand in a μ3-bridging mode via its amino and carboxyl groups.

Sensitive determination of buformin using poly-aminobenzoic acid modified glassy carbon electrode

Glassy carbon electrode, which is used to electrochemically determine the content of buformin, is modified with an electropolymerized film of p-aminobenzoic acid in pH 7.0 acetate buffer solution （ABS）. The polymer showed an excellent electrocatalytic activity for the reduction of buformin. In pH 7.0 ABS, the cathodic peak current increased linearly over three concentration intervals of buformin, and the detection limit （S/N=3） was 2.0 ×10^9 g/mL. The method was successfully applied to directly determine buformin in tablets with standard addition recoveries of 95.8 102.5%. The proposed method is simple, cheap and highly efficient.

Reactions with Aminobenzoic Acids via Diazonium Salts Open New Routes to Bio-Derived Aromatics

Aromatics have a broad application in our everyday life ranging from plastics, coatings and fibres, to food and pharmaceuticals. To date the bulk of these aromatics is derived from naphtha-based pet-rochemistry. However, recent progress in the fermentative production of metabolites using renew-able resources and engineered microbes has enabled the production of bio-precursors, such as 4-amino benzoic acid (pABA) and 2-amino benzoic acid (oABA). In this work we explored the feasibility of Sandmeyer reactions for the conversion of pABA to terephthalic and oABA salicylic acid, providing two very important platform chemicals for the chemical and pharmaceutical industries. We could demonstrate that both acids can be obtained from the amino benzoic acids derived from the shikimate pathway in microbes and plants. Good conversions could be achieved using Sandmeyer reactions at mild conditions with biodegradable reagents and without organic solvents.

Syntheses and Crystal Structures of Ternary Complexes of Zinc(Ⅱ) and Cadmium(Ⅱ) with 3-Aminobenzoic Acid and 1,10-Phenanthroline

Two new ternary complexes [Zη（3-aba）2（phen）]·2.58H2O 1 and {[Cd（3-aba）- （phen）2]·（NO3）·（1.5H2O） }n 2 （3-aba = 3-aminobenzoic acid anion, phen = 1,10-phenanthroline） were synthesized and characterized by elemental analysis, IR, UV spectrum and X-ray diffraction. Complex 1 crystallizes in the rhombohedral system, space group R3 with a = 3.5733（3）, b = 3.5733（3）, c = 1.1231（2） nm; V= 12.419（3） nm^3, C26H25.17NaO6.58Zn, Mr= 564.37, Z= 18, F（000） = 5253, μ= 0.937 mm^-1, Dc = 1.358 g/cm^3, R = 0.0668 and wR = 0.1690 for 2424 observed reflections （I〉 2σ（I））. Complex 2 belongs to the tetragonal system, space group P4/ncc with a = 2.88451（10）, b = 2.88451（10）, c = 1.55571（11） nm, V= 12.9441（11） nm^3, C31H25CdN6O6.50, Mr = 697.97, Z = 16, F（000） = 5648,μ=0.727 mm^-1, Dc= 1.433 g/cm^3, R = 0.0607 and wR = 0.1742 for 3468 observed reflections （I 〉 2σ（I））. Complex 1 displays a mononuclear structure. The carboxylate group of 3-aminobenzoic acid anion coordinates to Zn（Ⅱ） in a chelating bidentate mode, and the nitrogen atom of the ligand does not involve in coordination. Complex 2 exhibits a one-dimensional chain structure with 3-aminobenzoic acid anion coordinating to Cd（Ⅱ） in a μ2-bridging mode through its nitrogen atom and one of its oxygen atoms.

Studies on Solid State Reactions of Coordination Compounds（LXXI）──Solid State Reactions of o－Aminobenzoic Acid with Copper（Ⅱ） Acetate and Formate at Room Temperature

olid state reactions of o-aminobenzoic acid (HOAB) with Cu (OAc)_2·H_2O,Cu(HCOO)_2 · 4H_2O, anhydrous Cu (OAc)_2 and Cu (HCOO)_2 at room or close toroom temperature have been investigated. The product Cu(OAB)_2 with a high yieldwas synthesized very conveniently compared witb the solution phase method. Thekinetic behavior was studied by means of the isothermal electrical conductivity mea-surement. The reactivity was found to decrease in the order : Cu(OAc)_2· H_2O>Cu(OAc)_2>Cu (HCOO)_2 ·4H_2O>Cu (HCOO)_2, which was attributable to the crystalstructures of the copper salts.

铕-对氨基苯甲酸-邻菲咯啉配合物[Eu(p-ABA)_3Phen·H_2O](C_2H_5OH)的晶体结构

［Ｅｕ（ｐＡＢＡ）３Ｐｈｅｎ·Ｈ２Ｏ］（Ｃ２Ｈ５ＯＨ）（ｐＡＢＡ＝对氨基苯甲酸根，Ｐｈｅｎ＝邻菲咯啉）配合物晶体属三斜晶系，Ｐ１空间群，ａ＝１２２６８（３）ｎｍ，ｂ＝１４００５（３）ｎｍ，ｃ＝１０４４０（３）ｎｍ；α＝１０２６９（２）°，β＝１０８９３（２）°，γ＝９２８５（２）°；Ｚ＝２，Ｔ＝２７３Ｋ。最终的Ｒ因子为００３９。配合物中心Ｅｕ３＋离子与周围ｐＡＢＡ的６个氧原子和Ｐｈｅｎ的一对氮原子以及一个水分子的氧原子配位，配位多面体属畸变的单帽四方反棱柱体，水分子的氧原子占据帽位。

紫胶树脂的胺基化改性及其水性复合涂膜的性能

利用傅里叶变换红外光谱(FT-IR)、碳核磁共振(13C-NMR)及差示扫描量热仪(DSC)对改性紫胶树脂进行性能表征测试。结果表明,对氨基苯甲酸主要以酯化接枝至紫胶树脂中,改性紫胶树脂氨基物质的量浓度可达1.90 mmol/g,热寿命可由3.9 min延长至11.1 min。对改性紫胶树脂与不同类型聚合物(聚乙二醇、聚乙烯醇、聚丙烯酰胺和羟丙基甲基纤维素)复配后的水性涂膜进行性能测试,结果表明,改性紫胶树脂可通过乙二醛的羰氨反应提高涂膜的固化交联度,从而提升紫胶树脂在不同基材表面的附着力,其中金属基材的附着力可达5.61 MPa,附着力提升92.12%。乙二醛交联可将紫胶树脂的耐冲击、耐盐雾、耐水浸等性能分别提升至120 cm、72 h和720 h;聚乙二醇聚合物的引入还可以在保持涂膜耐水性能、耐盐雾性能的同时,使漆膜弯曲柔韧性得到提升。综上可知,本研究探索了以羰氨反应为基础的紫胶树脂改性新路径,为紫胶树脂的进一步开发和利用提供了新的原料和思路。

一维梯状配合物{[Cu_2(4,4′-bpy)_3(p-Ab)_2(H_2O)_2]·(NO_3)_2·4H_2O}_n的晶体结构

合成了一维分子梯状配合物{[Cu2(4,4′-bpy)3(p-Ab)2(H2O)2].(NO3)2.4H2O}n(4,4′-bpy=4,4′-联吡啶,p-Ab-=对氨基苯甲酸根离子),该配合物晶体属单斜晶系,P2(1)/c空间群,晶胞参数:a=1.1107(5)nm,b=1.5504(3)nm,c=1.4509(3)nm,β=104.81(3)°,V=2.4155(12)nm3,Z=2.铜离子周围有3个氧原子和3个氮原子与之配位,其中2个氧原子由对氨基苯甲酸的螯合氧原子提供,另一个氧原子由配位水提供,3个氮原子分别由三个4,4′-联吡啶提供.这六个原子在铜离子周围形成一个畸变的八面体配位环境.配体对氨基苯甲酸只有一种配位形式——双齿螯合,第二配体4,4′-联吡啶的两个氮原子均参与配位,将配合物组装成一维分子梯结构.

Fabrication of intercalated p-aminobenzoic acid into Zn-Ti layered double hydroxide and its application as UV absorbent

An organic ultraviolet （UV） ray absorbent, p-aminobenzoic acid （PABA） was intercalated into a Zn-Ti layered double hydroxide （LDH） precursor by an anion-exchange reaction to obtain ZnTi-PABA-LDH, a new organic-inorganic nanocomposite. The structure and the thermal stability of ZnTi-PABA-LDH were characterized by XRD, FT-IR and TG-DTA. The results indicate ZnTi-PABA-LDH, synthesized by this method, exhibit relatively high crystallinity, and markedly enhanced thermal stability of PABA after intercalation into ZnTi-LDH. The UV-vis-NIR spectrophotometric and ESR data show excellent UV ray resistance and greatly decreased photocatalytic activity when PABA is intercalated into the interlayers of the ZnTi-LDH. The studies suggest that ZnTi-PABA-LDH may have potential applications as safe sunscreen materials.

RP-HPLC法测定普鲁卡因肾上腺素注射液中盐酸普鲁卡因含量及其杂质对氨基苯甲酸

目的:采用RP-HPLC法同时测定普鲁卡因肾上腺素注射液中盐酸普鲁卡因含量及对氨基苯甲酸的方法。方法:色谱柱为Agilent-C18,流动相为水-乙腈-三乙胺(75∶25∶0.05),用冰醋酸调节pH3.3,流速为1.0mL·min-1,检测波长为286nm。结果:盐酸普鲁卡因检测浓度平均加样回收率为101.5%(RSD0.5,n=5),线性范围为0.8～3.2μg(r=0.9999)。结论:本法专属性强,操作简便,结果准确可靠。

The Inhibitive Effect of para-Amino Benzoic Acid and Its Polymer on Corrosion of Iron in 1 mol/L HC1 Solution

Poly p-aminobenzoic acid has been synthesized by chemical oxidation method. The inhibitive effect of poly p-aminobenzoic acid on iron in 1 mol/L HCI solution was investigated by polarization and electrochemical impedance spectroscopy and compared with that of monomer p-aminobenzoic acid. The effectiveness of poly p-aminobenzoic acid is very high in comparison with that of monomer. The results show that both cathodic and anodic processes were suppressed by p-aminobenzoic acid and poly p-aminobenzoic acid of iron dissolution in 1 mol/L HCI by their adsorption on the iron surface. The inhibition efficiency of both p-aminobenzoic acid and poly p-aminobenzoic acid were found to increase with the inhibitor concentrations. Ultraviolet （UV） reflectance studies of the iron surface after exposure to inhibitor acid show that poly p-aminobenzoic acid is strongly adsorbed on iron surface.

A Convenient and Practical Prepapation of Acetylphenyl Boronic Acids

A practical and scalable synthesis route of acetylphenylboronic acids is described. Bromoacetophenones(compounds 3a, 3b) were ketalized with ethylene glycol and triethyl orthoformate to give bromo ketals(compounds 4a_4c) in 60_80% yields. Compounds 4a_4b were treated with a Grignard reagent and then exchanged with borate to give p- and m-acetylphenyl boronic acids(compounds 5a and 5b) in 80% and 56% yields, respectively. The o-form(compound 5c) was obtained in 61% yield via the BuLi method.

不同质量浓度MS-222对红尾副鳅麻醉效果的影响

【目的】探究不同质量浓度间氨基苯甲酸乙酯甲磺酸盐(MS-222)对红尾副鳅(Paracobitis variegatus)的麻醉效果及其生理行为特征,为鱼类野外活体样本采集、驯养和繁育等科研生产活动提供麻醉技术并丰富鱼类麻醉理论。【方法】采用静水生物测试法,设置35.0、45.0、60.0、70.0、85.0、110.0、140.0、150.0、180.0和210.0 mg/L共10组MS-222质量浓度进行红尾副鳅麻醉试验,检测不同质量浓度MS-222药浴红尾副鳅后的麻醉和复苏阶段经过时间及呼吸频率,筛选适宜红尾副鳅驯养、繁育和疾病防治的MS-222麻醉剂质量浓度。【结果】依据MS-222麻醉红尾副鳅后其不同呼吸频率和行为特征,可将红尾副鳅麻醉程度分为应激期、轻度镇静期、深度镇静期、轻度麻醉期、麻醉期和深度麻醉期(A1~A6期)6个麻醉阶段,将复苏过程分为复苏期1~复苏期4(R1~R4期)4个复苏等级;10个质量浓度MS-222麻醉均能使红尾副鳅达到A6阶段,且均能复苏至R4等级。相关分析结果表明,MS-222质量浓度与麻醉时间呈显著负相关(R^(2)=-0.6003)(P<0.05,下同),与复苏时间呈显著正相关(R^(2)=0.7440);麻醉剂量均显著影响红尾副鳅的麻醉与复苏。各质量浓度MS-222处理红尾副鳅的呼吸频率均呈波浪式变化,麻醉和复苏阶段的呼吸频率均存在差异。在充氧条件下,35.0~210.0 mg/L MS-222处理红尾副鳅的复苏率均达100.0%。【结论】不同质量浓度MS-222处理红尾副鳅在麻醉和复苏阶段的呼吸频率均存在差异,理想的麻醉浓度区间为45.0~180.0 mg/L,110.0~180.0 mg/L的MS-222可用于红尾副鳅短时麻醉,45.0~85.0 mg/L的MS-222可用于红尾副鳅较长时间麻醉。

聚天冬氨酸/对氨基苯甲酸接枝共聚物的制备及阻垢缓蚀性能

以马来酸酐、尿素和对氨基苯甲酸(PABA)为原料,通过聚琥珀亚酰胺(PSI)与PABA的开环聚合反应,制备出聚天冬氨酸/对氨基苯甲酸共聚物(PASP-PABA)。利用红外光谱对共聚物的结构进行了表征,并通过静态实验和旋转挂片等方法考察了共聚物的阻垢、缓蚀性能。结果显示,PABA与PASP成功接枝共聚,形成了PASP-PABA共聚物。与PASP相比,PASP-PABA表现出更好的阻垢和缓蚀性能,且在阻垢剂浓度较低时,优势更加明显。

The solid state reactions of o-aminobenzoic acid with Zn(Ⅱ), Cu(Ⅱ), Ni(Ⅱ), Mn(Ⅱ) acetate hydrate at room temperature

The solid-solid state reactions of o-aminobenzoic acid with Zn(OAc)2.2H2O, Cu(OAc)2 .H2O, Ni(OAc)2.4H2O and Mn(OAc)2.4H2O result in the formation of corresponding complexes M(OAB)2 (M = Zn(Ⅱ), Cu(Ⅱ), Ni(Ⅱ), Mn(IⅡ)). XRD, IR and elemental analysis methods have been used to characterize the solid products. The activation energies of these reactions, which are calculated from the kinetic data obtained by means of the isothermal electrical conductivity measurement method, have been found to increase in the order: Cu(OAc)2.H2O(37.7 kJ.mol-1)~Mn(OAc)2.4H2O (39.7kJ.mol-1) < Zn(OAc)2.2H2O (56.3 kJ.mol-1) < Ni(OAc)2.4H2O (85.2 kJ.mol-1). The trend is related to their crystal structures.

Extraction of Aminobenzoic Acid with TOA and TBP

A series of extraction equilibrium experiments for aminobenzoic acid were carried out. Tri n octylamine (TOA) and tributyl phosphate (TBP) were selected as complexing agents. 1 Octanol and kerosene were selected as diluents. The effects of extractant concentration and pH on the distribution ratio were discussed in detail. It was found that there are ion pair association and hydrogen bond complexing in the extraction. Expressions of the equilibrium distribution for different solvent systems are proposed. The precision of the models is satisfactoy.

HPLC法测定N-对氨基苯甲酰-L-谷氨酸中杂质含量

采用高效液相色谱法,检测原料N-对氨基苯甲酰-L-谷氨酸中对氨基苯甲酸、对硝基苯甲酸、N-对硝基苯甲酰-L-谷氨酸的含量。色谱柱:5μm 150 mm×4.6 mm C18,检测波长:245 nm,进样量:20μL,流速:1.2 mL/min,柱温:40℃。结果表明,对氨基苯甲酸与N对氨基苯甲酰-L-谷氨酸的分离度为4.82,杂质对氨基苯甲酸在0.01009~0.6054μg/mL(r=0.9997)、对硝基苯甲酸在0.025~0.6000μg/mL(r=0.9990)、N-对硝基苯甲酰-L-谷氨酸在0.027027~0.6006μg/mL(r=0.9998)范围内线性关系良好。该方法简便、灵敏、可靠、重复性好,因而可作为N-对氨基苯甲酰-L-谷氨酸中杂质含量的控制方法。