共查询到20条相似文献,搜索用时 62 毫秒
1.
2.
3.
采用在线热裂解/气相色谱-质谱(Py/GC-MS)联用技术对3-吡啶甲酸茴香酯进行热裂解分析。通过酰氯化和酯化反应合成了新型目标化合物3-吡啶甲酸茴香酯,其分子式为C14H14NO3。目标化合物的结构经核磁氢谱(1H NMR)、核磁碳谱(13C NMR)、红外光谱(IR)和高分辨质谱(HRMS)进行确证,并通过热重-微热重-差示扫描量热(TG-DTG-DSC)分析方法对目标化合物的热稳定性进行分析。在空气氛围中,将目标化合物分别于300,600,900℃下进行热裂解,并通过气相色谱-质谱法对其挥发性热裂解产物进行定性和半定量分析。研究显示:目标化合物共经历了两次失重过程。第一次失重在129.9~158.9℃之间,失重2.3%;第二次失重在158.9~274.9℃之间,失重达90.1%,230.1℃时失重率最大。热裂解共产生44种产物,包括具有香味特征的大茴香醛、对甲基苯酚、松油醇、D-香茅醇、大茴香醚和茴香醚等化合物。其中裂解温度对裂解产物的种类和相对含量具有明显影响。300℃时α-二去氢菖蒲烯的相对含量最高,600,900℃时,相对含量最高的分别是大茴香醛和对甲基苯酚。苯甲醛、茴香醚和大茴香醚的相对含量随着温度的升高呈先增加后降低趋势;而对甲基苯酚含量则随着温度的升高而增加。根据主要裂解产物及其相对含量的变化,对目标化合物的裂解机理进行了初步探讨。 相似文献
4.
5.
6.
7.
8.
9.
在无水KF-CH3OH体系中直接电氧化合成的茴香醛二甲基缩醛(p-MBDMA)遇水易发生水解。研究表明在甲醇、乙腈和水的酸性混合溶液中,p-MBDMA在色谱柱中能迅速彻底地水解为茴香醛,故利用其水解反应建立了一种间接测定p-MBDMA的高效液相色谱(HPLC)方法。选择最佳流动相为水-甲醇-乙腈(50:30:20),用磷酸调节pH值至3.0,并探讨了测定机理。建立的HPLC测定方法准确、可靠,已应用于电化学合成p-MBDMA的分析,并可满足工业化生产的分析要求。 相似文献
10.
以具有三维开放网络结构的薄层大面积烧结8 μm金属纤维(SMF-Ni, SMF-SS(316L不锈钢))为基底, 通过乙烯催化化学气相沉积在金属纤维表面生长碳纳米管(CNTs)的方法, 制备了整体式CNTs/SMF-Ni (CNTs: 50% (w))和CNTs/SMF-SS (CNTs: 40% (w))复合材料. 研究表明, 以CNTs/SMF-Ni 为阴极材料、SMF-SS为阳极材料, 具有很高的直接电催化氧气氧化对甲氧基甲苯(茴香醚)合成对甲氧基苯甲醛(茴香醛) 的活性, 反应物转化率和产物选择性分别达95.4%和96.5%, 电流效率可超过80%. 相似文献
11.
Wenbi Guan 《International journal of environmental analytical chemistry》2013,93(6):679-691
A QuEChERS (quick, easy, cheap, effective, rugged, and safe) method for the determination of benazolin-ethyl and quizalofop-p-ethyl in rape and soil by high-performance liquid chromatography-tandem mass spectrometry has been developed in this study. The residue and dissipation of benazolin-ethyl and quizalofop-p-ethyl in rape and soil were determined with the developed method. The half-lives of benazolin-ethyl in rape straw and soil were 3.7–5.1 days and 14.3–26.3 days, respectively. The half-lives of quizalofop-p-ethyl in rape straw and soil were 5.0-6.1 days and 0.3–9.7 days, respectively. The residue of benazolin-ethyl and quizalofop-p-ethyl in rapeseed and soil were below the detection limit (i.e., 0.5?mg?kg?1, the maximum residue level of European Union for quizalofop-p-ethyl). 相似文献
12.
13.
多环芳二酐型聚酯亚胺膜的透气性能李悦生,丁孟贤,徐纪平(浙江大学高分子科学与工程研究所,杭州,310027)(中国科学院长春应用化学研究所)关键词聚醚酰亚胺,聚酯酰亚胺,膜,透气性通常的聚酰亚胺加工性能较差,在芳环二酐的苯环间引入醚键等柔性基团后,其... 相似文献
14.
微量元素与疾病诊断治疗的研究现状及展望 总被引:8,自引:0,他引:8
对国内外微量元素与疾病的关系及其诊断治疗的研究现状及研究动向进行了综述,包括:微量元素与地方病、癌肿、心血管病、糖尿病、眼病、神经系统病等。参考文献72篇。 相似文献
15.
Charles Manzi-Nshuti 《Polymer Degradation and Stability》2007,92(10):1803-1812
In this work, ferrocene- and ferrocenium-containing salts were employed to modify montmorillonite. X-ray measurements show an increase in the interlayer spacing upon clay modification, which means that the larger and more organophilic cations were inserted into the gallery space of montmorillonite. Attempts to prepare nanocomposites of polystyrene and ethylene vinyl acetate copolymers lead to immiscible systems; the morphology of these systems was elucidated with TEM, XRD and cone calorimetry. The thermal stability of the composites is greater than that of the virgin polymer. 相似文献
16.
Prof. Inmaculada García‐Moreno Lu Wang Prof. Angel Costela Dr. Jorge Bañuelos Prof. Iñigo López Arbeloa Prof. Yi Xiao 《Chemphyschem》2012,13(17):3923-3931
Herein, we present the synthetic route and the photophysical, electrochemical as well as laser properties of novel red‐emitting boron‐dipyrromethenes (BODIPYs) bearing arylethyne moieties. Such functionality is added along the main axis of the chromophore leading to single‐ and double‐substituted derivatives. The relationship between the dye structure and the lasing properties is studied in detail with the help of the photophysical and electrochemical properties as well as quantum mechanical simulations. The asymmetric substitution of the parent dye induces inhomogeneities in the charge distribution, which leads to an overall loss of the fluorescence capacity, mainly in polar media. Such non‐radiative deactivation processes can be softened by decreasing the electron‐donor ability of the substituent or even avoided by symmetrical substitution. Thus, grafting of the arylethyne moieties at the longitudinal axis of the indacene core results in an effective strategy to develop red‐edge BODIPYs with highly efficient and photostable laser emission. 相似文献
17.
The monomeric ν(N—H) vibrations of various trisubstituted ureas of the R2UPh type and -thioureas of the R2TUPh type have been studied. The trans—out isomerism in the former and the trans—out—cis isomerism in the latter are discussed from the point of view of steric effect. The monomeric ν(N—H) vibrations of RPhUPh and RPhTUPh are also examined. The single band appearing in the spectrum of both ureas is characteristic of the cis form; this suggests the existence of phenyl—phenyl interaction (the stacking interaction proposed by Galabov et al. [10]). Behavior of ν(N—H) vibrations at several concentrations is shown to be clearly different in the three forms (trans, out and cis). The presence of the cis form is confirmed by solvent effect experiments. 相似文献
18.
19.
20.
Ti-V基储氢合金在室温、常压下即可表现出良好的储氢特性,且质量储氢容量明显高于传统AB5型储氢合金,从而在氢气的精制和回收、运输和储存及热泵等方面有较早的应用。 此外,在混合气体分离、核反应堆中处理氢的同位素、镍氢电池及燃料电池负极材料等方面也得到了广泛的研究与关注。 基于目前Ti-V基储氢合金的研究现状,概述了该类合金的优势、限制性因素(包括成因)及改性手段。 此外,为了进一步理解Ti-V基合金储氢机理、构建合金组分与储氢特性之间的对应关系,本工作重点围绕Ti-V基储氢合金及其氢化物的结构、组分优化设计展开综述,并对其未来研究方向做出展望。 相似文献