共查询到19条相似文献,搜索用时 226 毫秒
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研究了以乙酸铜、硝酸铵为氧化剂,在微波条件下,用400W的功率,15min即可获得很高的苯偶酰产率(85.8%),是一种有效的苯偶姻氧化反应新方法。 相似文献
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苯作为具有代表性的一种常见挥发性有机污染物在居住环境及工作场所中普遍存在并备受关注。活性炭纤维(ACF)由于其孔径分布特点及纤维表面特征,对挥发性和半挥发性有机物具有吸附量大、吸附效率高的优点,有可能在吸附解析法测量空气中苯和苯的处理上具有比目前常用的颗粒活性炭(GAC)更好的应用前景,因此文中对两种吸附材料的吸附容量、对不同浓度苯的吸附效率、对苯的选择吸附性等各项吸附能力指标进行了考察。 相似文献
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以[Ca24Al28O64]4+·4O-(C12A7-O-)为催化剂,在流动反应器中研究了苯羟基化合成苯酚的转化率以及苯酚的选择性.苯的转化率随反应温度增加而增加,苯酚的选择性与温度及反应物的组成有关.此外还通过XRD、EPR和FT-IR对催化剂的结构,表面及内部物种进行了考察.结果表明,C12A7-O-的电正性骨架结构在反应前后几乎没有任何差别,样品内部有部分O-和O2-在反应后转化为OH-.中性物种及负离子中间体分别由Q-MS和TOF-MS所检测.活性的O-和OH-被认为在苯酚形成过程中起了重要作用. 相似文献
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采用活性碳吸附,二硫化碳解吸进样,利用DB-1毛细管色谱柱采用恒温条件分离,以FID为检测器,同时测定空气或废气中乙酸乙酯、乙酸丁酯、环己酮、苯系物。结果表明,该方法分离效果好,精密度高,准确度高,分析时间短,适合空气或废气环境分析的要求,结果令人满意。 相似文献
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利用三聚氰胺、甲醛和苯代三聚氰胺增韧剂在碱性条件下制备了改性三聚氰胺甲醛树脂(BG-MF),并将其浸渍牛皮纸使用直接浸渍方法来制得层积板。研究加入不同添加量的苯代三聚氰胺对共缩聚树脂结构、结晶性、力学性能、耐燃烧、耐沸水等性能的影响。核磁共振氢谱图(1H-NMR)结果显示,改性后树脂BG-MF在化学位移δ7.0~7.6处出现了尖锐的特征峰,主要归属于苯代三聚氰胺中的苯环的氢质子峰;红外光谱(FTIR)结果显示,BG-MF红外结果除了与三聚氰胺甲醛树脂(MF)具有相同的特征吸附峰外,在1 557和774 cm-1出现了新的特征吸收峰,主要归属于苯代三聚氰胺中的苯环骨架的特征吸收峰,说明苯代三聚氰胺参与缩聚反应。X射线衍射图谱分析说明BG加入后晶型有轻微变化,主要是由于MF中含有N元素,有大量的氢键产生,进而形成不规则的部分微小晶体。改性后树脂用于浸渍层积板的制备,DMA测试结果显示,当BG含量达到15%时在137.2 ℃储能模量为20 228 MPa,比未改性MF树脂的峰顶储能模量17 050 MPa提高了18.6%,表明改性后树脂胶接强度提高。从拉伸实验结果可以看出,苯代三聚氰胺含量约为15%时,增韧效果最好。氧指数从36.2升高到38.4,表明苯代三聚氰胺的加入其阻燃性能有所增强。 相似文献
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研究苯在30 Torr和1360~1820 K下的热解过程.利用同步辐射真空紫外光电离质谱技术对热解产物进行了检测,并对其随温度变化的摩尔分数曲线进行了测量.建立了一个低压苯热解动力学模型,并结合生成速率分析展示了燃料分解和芳烃生长过程中的主要反应网络.结果显示苯的分解主要通过氢提取反应生成苯基进行,部分通过单分子解离反应生成丙炔基或苯基进行,并终止于乙炔、丁二炔及1,3,5-己三炔等具有高热稳定性的聚炔烃类物种的生成.此外,低压苯热解中的芳烃生长过程起始于苯和苯基,并主要受到偶数碳增长机理控制.这是由于奇数碳增长机理所依赖的C5和C7物种在低压苯热解中很难生成. 相似文献
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Sonolysis of chlorobenzene in Fenton-type aqueous systems 总被引:4,自引:0,他引:4
The influence of ultrasounds (200 kHz frequency) on the decomposition of chlorobenzene (CB) in a water solution (around 100 ppm concentration) containing iron or palladium sulfates was investigated. The intermediates of the sonolysis were identified, thus allowing a deeper insight into the degradation mechanism. It was established that CB degradation starts by pyrolysis inside the cavitation bubbles. The initial sonolysis product is benzene, formed in a reaction occurring outside the cavitation from phenyl radicals and the hydrogen atoms sonolytically generated from the water. Polyphenols as products of the CB sonochemical degradation are reported for the first time. The palladium salt was found to be a useful and sensitive indicator for differentiating the sites and mechanisms of the product formation. An alternative mechanism for the CB sonolysis is advanced, explaining the formation of phenols, polyphenols, chlorophenols and benzene. 相似文献
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Non-thermal plasma (NTP) and combined plasma-MnO2 catalytic (CPMC) air cleaners were tested for removal of low-concentration benzene in air. Both air cleaners were made of stainless steel needle matrix plate and used DC corona discharger. The effects of discharge power and relative humidity (RH) on benzene removal efficiency were investigated in a closed chamber. The intermediate products produced in purification processes were analyzed using gas chromatography-mass spectrometer (GC-MS). The concentrations of discharge byproducts and CO2 selectivity produced in both processes were also compared. It was found that the benzene removal efficiency increased with discharge power in both systems; With the increase of RH in air, benzene removal efficiency firstly increased and then decreased in NTP while it gradually decreased in CPMC. For a fixed discharge power of 9 W and RH of 20% in CPMC, the conversion of benzene increased from 82.9% to 89.6%, the CO2 selectivity increased from 38% to 80%, the concentration of O3 decreased from 25.3 ppm to 1.3 ppm, and NO2 formation decreased from 234 ppm to 25.7 ppm, compared with NTP. 相似文献
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Decomposition of benzene was investigated using single and two-stage stainless steel reactors with application of high-voltage AC and DC currents. Benzene removal, CO, and CO2 were measured as a function of reactor diameter, applied voltage, and stage of reactor configuration. The results showed that, benzene removal and CO2 selectivity improved in two-stage configuration and reached up to 59% and 97.8% respectively, where the gap size was 8.5 mm. Formation of OH, N-H and N=O function groups were seen in the exhaust gas. Subsequently, organic acids, phenols, and alcohols were identified as the main byproduct of benzene decomposition considering GC-MS analysis. 相似文献
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The present work aims at developing a new process to selectively synthesize sulfoxide from sulfides using ultrasound. Methyl phenyl sulfide (MPS) has been taken as a model reactant. The reaction has been carried out in ultrasonic bath with an operating frequency of 22 kHz and maximum power supply of 120 W with an actual power dissipation of approximately 40 W measured using calorimetric studies. Effect of various parameters such as presence and absence of catalyst, type of catalyst (catalysts used were sodium tungstate and ammonium molybdate), temperature, concentration of hydrogen peroxide, effect of molar ratio of MPS to H(2)O(2) has been investigated with an aim of obtaining the optimum conditions for the synthesis of sulfoxides. It was observed that the presence of catalyst is a must to achieve appreciable conversions. It was also observed that the periodic addition of stoichiometric amount of hydrogen peroxide instead of sudden addition of it (total quantity of hydrogen peroxide remains the same) gave better selectivity for sulfoxide. The maximum conversion achieved in the present work was approximately 88.42% with sulfone formation being only 0.4% indicating a 99.6% selectivity for the desired product i.e. sulfoxides. 相似文献
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通过Suzuki偶联反应将2,7-二溴-9,9-二辛基芴(Br-DOF)、2,7-二硼酸-9,9-二辛基芴(B-DOF)和4-(8-(2,7-二溴-9-辛基芴)辛氧基)-N-4-(7-(4-(二苯胺基)苯基)苯并噻二唑)苯基-二苯胺(Br-TAF)共聚,合成了白光聚合物PDOF-TAF。以PDOF-TAF为发光层,溶液旋涂制备了非掺杂型单层白光有机电致发光二极管,色坐标为(0.23,0.18)。通过插入电子传输层TPBI和空穴传输层PVK得到的白光器件发射光谱覆盖了410~700 nm区域,色坐标从(0.23,0.18)调整到(0.24,0.32),亮度达到2 020 cd/m2,电流效率达到1.4 cd/A。实验结果表明,PDOF-TAF是一种很好的白光聚合物发光材料,在WOLED中将有很好的应用前景。 相似文献
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Electrochemical and XPS studies of decylamides of α-amino acids adsorption on carbon steel in acidic environment 总被引:2,自引:0,他引:2
O. Olivares N.V. Likhanova B. Gómez M.E. Llanos-Serrano J.M. Hallen 《Applied Surface Science》2006,252(8):2894-2909
Corrosion inhibition of steel in hydrochloric acid by decylamides of α-amino acids derivatives was studied using gravimetric and electrochemical techniques. Protection efficiencies of 90% were obtained with 100 ppm of tyrosine and glycine derivatives, while alanine and valine derivatives reached only 80%. The order of increasing inhibition efficiency was correlated with the modification of the molecular structure of inhibitors. Potentiodynamic polarization curves indicated that both the decylamide of tyrosine and glycine acted primarily as anodic type inhibitors, whereas the decylamide of alanine and valine were of the cathodic type. Thermodynamic parameters and Flory-Huggins adsorption isotherms described the experimental findings. The number of active sites, equilibrium constant, enthalpy and change of free energy were computed for all inhibitors studied. This information suggested that organic molecules were adsorbed and displaced water molecules from the steel surface. X-ray photoelectron spectroscopy confirmed that species of N, C and O interacted with steel to form a continuous protective film. 相似文献