碳苷研究 V: 用Grignard试剂合成取代苯酚中酚羟基的保护及脱保护

本文报道了一些取代苯酚的合成, 并探讨了用Grignard试剂合成取代苯酚中酚羟基的保护及脱保护的问题. 利用苄基和甲基作为酚羟基的保护基, 对文献报道的切断醚键脱保护方法进行了评价. 找到了两种新体系能在更温和条件下切断醚键的方法, 指出了它们的适用条件. 实验结果符合硬软酸碱理论.     

FT-IR, FT-Raman spectra, density functional computations of the vibrational spectra and molecular geometry of biomolecule 5-aminouracil

FT-IR and FT-Raman spectra of the biomolecule 5-aminouracil were recorded in the regions 400–4000 cm⁻¹ and 10–3500 cm⁻¹, respectively. The observed vibrational wavenumbers were analyzed and assigned to different normal modes of vibration of the molecule. Density functional calculations were performed to support wavenumber assignments of the observed bands. A comparison with the molecule of uracil was made, and specific scale factors were employed in the predicted wavenumbers of 5-aminouracil. With the purpose of study the important molecule 5-aminouracil, its equilibrium geometry and harmonic wavenumbers were calculated for the first time by the B3LYP DFT method. The vibrational wavenumbers were compared with IR and Raman experimental data. Also good reproduction of the experimental wavenumbers is obtained and the % error is very small. All the tautomeric forms of 5-aminouracil were determined and optimized. The dimer forms were also simulated. The energy, atomic charges and dipole moments were discussed and several general conclusions were underlined.     

Preparation and properties of polyurethane networks based on α,ω-difunctional poly(hexafluoropropylene oxide)

Poly(hexafluoropropylene oxide), poly(HFPO), networks were prepared from functional polymers by end linking via urethane groups. The prepolymers were characterized by NMR spectroscopy and GPC. The networks were characterized by determination of the number of network chains from the shear modulus, and were snown to contain both trifunctional crosslinks and difunctional links. The properties of the networks were investigated by a range of techniques. Compared with fully-fluorinated networks formed via triazine cross-links, investigated previously, the urethane-linked networks were more readily prepared but were poorer elastomers, were less thermally stable, and were less resistant to swelling by common polar solvents. © 1995 John Wiley & Sons, Inc.     

南瓜籽烘烤前后化学成分的分析

对烘烤前后南瓜籽中的化学成分进行分析并对比。采用同时蒸馏萃取装置萃取南瓜籽中的挥发性成分,采取超临界CO2萃取技术萃取南瓜籽油脂,并将其分为酸、碱、中性三个部分,用气相色谱-质谱联用方法分析其中化学成分并进行对比。结果表明,南瓜籽挥发性成分中含有多种醛类和酯类化合物,烘烤后产生了大量的烷基吡嗪,其在碱性部分中的相对含量比烘烤前提高14倍多,不饱和醛类化合物含量也有明显提高。南瓜籽油脂中的主要化学成分是油酸、亚油酸及其酯类。还含有生物活性功能成分如植物甾醇、角鲨烯和维生素E等。烘烤后除角鲨烯含量有所降低,维生素E、植物甾醇、亚麻酸等均有提高。     

Gas chromatography-olfactometry analysis of the volatile compounds of two commercial Irish beef meats

The volatile flavour compounds of two commercial Irish beef meats (labelled as conventional and organic) were evaluated by gas chromatography-olfactometry and were identified by gas chromatography-mass spectrometry. The volatile compounds were isolated in a model mouth system. Gas chromatography-olfactometry was performed by a group of eight assessors using the detection frequency methodology. The odours of the detected compounds were described as well. Eighty-one volatile compounds were identified, 11 compounds of which possessed odour activity in the first beef sample and 14 of which in the second meat sample. Ten volatile flavour compounds were common to both: methanethiol, dimethyl sulphide, 2-butanone, ethyl acetate, 2- and 3-methylbutanal, an unknown compound, 2-octanone, decanal and benzothiazole. Two unknown compounds were only detected in the first sample while 2,3-pentanedione, 4-methyl-3-penten-2-one, 2-heptanone, dimethyl trisulphide and nonanal were only perceived in the second beef. Significant differences in terms of detection frequency, odour characteristics and in nature of the volatile flavour compounds were emphasised between the two samples.     

等离子体发射光谱法测定茶水中无机元素的含量

采用电感耦合等离子体发射光谱法对茶水中的无机元素进行分析,对其中的Cu、Zn、Mn、P、Fe5种元素进行定量,讨论了等离子体发射光谱法最佳实验条件及影响茶叶中无机元素浸出量的因素。Cu、Zn、Mn、P、Fe的回收率为92．5％～103．5％,测定结果的相对标准偏差为1．34％-4．5％（n=5）。     

Mg/Al型水滑石吸附硼的实验研究

采用共沉淀法制备了几种不同摩尔比的镁铝水滑石(LDHs),并对其进行了XRD、FT-IR表征.将其应用于吸附溶液中的硼,比较了它们对硼的吸附容量,最终选择了具有较高吸附容量的Mg4Al-LDH作为硼吸附荆.对Mg4Al-LDH吸附硼的实验条件进行了系统研究,得到了较高吸附容量下的实验条件.试验结果表明该等温吸附过程可用Langmuir吸附等温模型准确描述.     

Synthesis,characterization, and antimicrobial activity of some novel poly(ether ketone)s

Low molecular weight poly(ether ketone)s were synthesized from phenol, 1,4‐phenylenedioxy diacetylchloride, chloroacetylchloride, and dichloroalkanes [1,2‐dichloroethane and dichloromethane] by a Friedel–Crafts reaction with anhydrous aluminum chloride as a catalyst and carbon disulfide as a solvent. The conditions for the preparation of the poly(ether ketone)s and the chlorine contents obtained with the Carius method were examined, and a reaction scheme for each resin was established. The molecular weights and polydispersities of the resins were obtained by gel permeation chromatography. The polyketones were characterized by IR spectroscopy. The characteristic frequencies due to different functional groups were assigned. The thermal properties of the resins were studied with thermogravimetry and differential scanning calorimetry. The characteristic temperatures of thermal degradation for the poly(ether ketone)s were evaluated with thermogravimetric analysis. The kinetic parameters for the decomposition reactions of the resins were obtained with Broido and Doyle's method, and the heats of fusion were obtained from differential scanning calorimetry thermograms. The polyketones were thermally stable up to 200 °C. All the polyketones were tested for their microbial properties against bacteria, fungi, and yeast. The effect of poly(ether ketone)s on the growth of these microorganisms was investigated, and the polyketones were found to inhibit the growth of the microorganisms to a considerable extent. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2335–2344, 2003     

幼儿身高、体重和头发、血液锌铅含量关系的研究

同步检测了151例3-4岁健康幼儿的身高、体重以及头和全血中的锌、铅含量。研究了身高、体重和锌、铅含量的关系,指出无论是发锌或血锌含量与身高、体重多数呈正相关,但发铅与身高、体重主要呈负相关,血铅与身高、体重的关系较为复杂,多为非线性的二次函数关系。     

玩具、铅笔中可溶性砷、锑、硒的形态分析

对玩具、铅笔中可溶性砷、锑、硒的形态分析方法进行了研究,对原子荧光光谱法测定不同价态砷、锑、硒的方法进行了优化,建立了砷、锑、硒的原子荧光光谱形态分析方法。该方法样品加标回收率为82.0%~110.0%,测定结果的相对标准偏差为1.35%~2.22%(n=10)。     

Preparation of Titania/PDMS Hybrid Films and the Conversion to Porous Materials

Transparent films of titania/poly(dimethylsiloxane) (PDMS) hybrids were prepared by the solvent evaporation from the precursor solution prepared by the co-hydrolysis and co-condensation of titanium tetraisopropoxide and a methoxy-functionalized PDMS. The hybrid films were flexible and had high homogeneity of the composition. The organic groups of PDMS were decomposed at 400°C in air to form porous films. Though the heated films were rather brittle compared to the as-synthesized films, they were still transparent and homogeneous. The BET surface areas of the films after the heat treatment at 400°C were over 300 m²/g, while the as-synthesized hybrid films were non porous. According to the BDDT classification, the nitrogen adsorption/desorption isotherms of the calcined films were Type I, showing that the films were microporous. The titania domains were still amorphous after the heat treatment at 400°C and transformed to anatase after the heat treatment at 1,000°C.     

固态萃取搅拌棒技术与气相色谱联用测定植物中的有机氯农药

以固态萃取搅拌棒为样品前处理技术,采用气相色谱法分析了荞麦和苦参中的8种有机氯农药残留。实验对比了聚醚砜酮(PPESK)和聚二甲基硅氧烷(PDMS)对所测定的有机氯农药的相对萃取量(以峰面积计),发现前者是后者的1～11倍。用PPESK作萃取相,对萃取温度、萃取时间和盐浓度等萃取条件进行了优化,并考察了基质效应对萃取效率的影响。所用方法对荞麦中有机氯农药的LOD为4～85pg/g,重复性的RSD小于26%,回收率为83%～135%;对苦参中有机氯农药的LOD为3～17pg/g,重复性的RSD小于17%,回收率为82%～128%。     

电感耦合等离子体质谱法测定铁基体中稀土元素Nd和Dy

采用电感耦合等离子体质谱法测定铁基体中的稀土元素Nd和Dy,选择187Re作为内标以校正仪器的信号漂移,Nd和Dy元素的浓度与信号强度线性关系良好,相关系数(r2)分别为0.9998和0.9997,该方法测定Nd和Dy元素的检出限分别为0.02 ng/mL和0.006 ng/mL,平均回收率分别为99.5％和97.4％,测定结果的相对标准偏差分别为3.5％和4.3％.     

二芴及其衍生物的结构优化、前线轨道及其性质的理论研究

采用DFT/B3LYP方法对系列二芴体系进行了全优化, 对其结构特征进行对比. 在此基础上, 得到各分子的最高占据轨道和最低空轨道能量关系及HOMO-LUMO能隙, 并分析其能隙与导电性的关系及预计其光谱特征. 对各分子的相关热力学性质进行了研究. 热力学参数表明各分子均较稳定, 其中化合物DFBT最稳定. 采用ZINDO和TD-DFT方法计算其吸收光谱, 分析结构特征对光谱性质的影响. 二芴中插入共轭程度高的结构后, 分子的共轭程度增加; HOMO-LUMO能隙变窄; 最低激发能降低, 导电性增强; 吸收光谱红移. 而接入扭曲的结构后, 共轭程度降低; HOMO-LUMO能隙变宽; 最低激发能有所升高, 导电性下降; 吸收光谱蓝移.     

Designing Fixed Bed Column and Batch Studies of Chitosan Nanoparticles for Defluoridation of Drinking Water

The aim of present investigation was to prepare nanoparticles of chitosan and perform batch and column studies with them to study their defluoridation capacity. The nanoparticles of chitosan were characterized by techniques like FTIR, SEM, TEM, etc. Effect of initial fluoride concentration, adsorbent dose, pH and temperature were studied in the batch studies. Effect of bed height, flow rate, and inlet concentration on the column performance were studied. Performance of packed columns were described through the concept of breakthrough curves and column parameters were predicted as a function of bed heights. The breakthrough curves were defined by the Adams-Bohart and Wolborska models.     

云南菊科中草药中铅含量特征分析

论述了云南２７种菊科中草药及其水提取物中铅含量的特征。菊科植物及水提物中铅含量的频数分布为正偏态,两者的相关系数ｒ＝０．０９,未呈现显著的线性相关。提取率较高的山紫苑、佩兰、木香铅实际含量低;铅含量高的叶下花、狭叶兔耳风、臭灵丹提取率又较低,减少了人体对Ｐｂ的过量摄入。     

顶空-气相色谱-飞行时间质谱鉴定分析饮用水中的异味成分

使用顶空-气相色谱-飞行时间质谱结合差异化分析软件鉴定分析出了饮用水中的异味物质。质谱数据通过逐级筛查，降低化合物数量，通过T检验和倍数变化统计分析查找差异显著的化合物，利用结构解析确定异味成分为乙醛。通过正交试验优化了加热时间、加热温度、样品量和加盐量等因素。检出限和定量限分别为0.0033和0.010 mg/L，线性范围为0.010~0.500 mg/L，相关系数R²=0.997。对实际样品进行了检测，分析了产生异味的原因，并对相应的生产加工工艺提出了合理化建议。该方法简便、快速、灵敏，适用于鉴定分析饮用水中的异味成分。     

芝罘湾表层沉积物中重金属的分布特征及潜在生态危害评价

为了解芝罘湾沉积物中重金属的污染状况,于2009年7月采集了黄海芝罘湾16个站位的表层沉积物并测定了其中的重金属含量.芝罘湾的重金属污染程度较低,所有测定值均低于国家海洋沉积物Ⅰ类质量标准.Hg、Cu、Pb、Cd、Zn、Ni、Co、Mn 8种重金属的平均含量分别为0.02、12.3、8.67、0.13、32.8、11....     

膜催化研究II. 多孔无要膜的制备与表征及其反应器对甲醇脱氢反应的促进作用

采用溶胶-凝胶法制备了多孔氧化铝膜, 并通过DSC、TGA、SEM、N~2吸附和气体透过率测定等手段, 对膜的性能进行了表征。结果表明, 用这种方法制备的多孔氧化铝膜是一种均匀无裂痕和具有较窄孔径分布(约4nm)的膜材料。将此多孔氧化铝膜制成膜反应器后, 用于甲醇催化脱氢制甲醛的反应, 发现甲醇转化率比常规反应器有较大幅度的提高。同时首次尝试采用溶胶-凝胶法将催化活性组分直接负载到多孔氧化铝膜上, 从而得到了一种具有催化活性的多孔膜, 并考察了它的反应活性。文中对由这两种多孔膜及钯/陶瓷复合膜制成的反应器的特点进行了比较。     

N-羧基吡啶功能化离子液体的表征

合成了系列新型N-羧基吡啶功能化离子液体, 利用1H NMR、13C NMR、IR、DSC对其进行表征并研究了其与常规溶剂的相溶性, 采用酸碱滴定法测量了系列离子液体的酸离解常数pKa值. N-羧基取代吡啶功能化离子液体的pKa值在2.5~4.0之间, 并随阳离子取代羧基碳链的增长而增大; 离子之间形成氢键及阴、阳离子的大小是影响离子液体熔点的主要因素. 阴离子越小, 熔点越高. 所合成的N-羧基吡啶功能化离子液体具有相同的相溶性且由取代羧基所决定, 与常见烷基咪唑离子液体相比, N-羧基吡啶功能化离子液体与丙酮、二氯甲烷并不相溶. 功能化离子液体的阳离子取代基是影响其物化性能的主要因素, 通过改变功能化基团碳链的长短及与不同阴离子进行组合, 可以对功能化离子液体物理、化学性能进行调节.