乙醚的荧光光谱及其特性

用UV-240紫外分光光度计和SP-2558多功能光谱测量系统,通过测量紫外吸收光谱和荧光光谱,对乙醚在紫外光激励下的光谱特性进行了实验研究.发现,乙醚能吸收波长小于304 nm的紫外光,产生强的荧光;乙醚的荧光峰是波长306 nm至345 nm范围的宽谱峰,峰值波长在317 nm左右.分析得出,乙醚吸收紫外光、产生荧光光谱是其分子中氧原子上的孤对电子跃迁所为.由此对乙醚荧光光谱的产生机理和特性作出了解释,并计算出了乙醚分子相应能级差.这些结果可为乙醚这种重要溶剂和麻醉剂的应用提供帮助.     

马骝卵挥发油的GC-MS分析

气相色谱 -质谱联用研究了中药马骝卵的挥发油化学成分 ,共鉴定出 17种成分 ,占色谱总溜出峰面积的 5 8.5 2 %。其中主要成分为十六酸乙酯、十六酸正丁酯、月桂酸乙酯、亚油酸乙酯、顺式 -油酸乙酯、9,12 -二烯 -十八酸丁酯、顺 - 9-烯 -硬脂酸丁酯、十二酸乙酯、雪松醇、2 ,3,4 ,7,8,8a-六氢化 1H- 3a,7-亚甲基奥。     

Photoelectron Spectra of Carbonyls. Oxalyl Chloride,Ethyl Oxalyl Choride,Ethyl Oxamate and N,N-Dimethyl Ethyl Oxamate

Photoelectron spectra are reported for oxalyl chloride, ethyl oxalyl chloride, ethyl oxamate and N,N-dimethyl ethyl oxamate. The spectra are assigned using a composite molecule approach.     

Ultrasound promoted ZrCl(4) catalyzed rapid synthesis of substituted 1,2,3,4-tetrahydropyrimidine-2-ones in solvent or dry media

Sonication of aromatic aldehydes, urea and ethyl acetoacetate in presence of solvent (ethyl alcohol) or solvent-less dry media (bentonite clay) supported-zirconium (IV) chloride (ZrCl(4)) as catalyst at 35 kHz gives 6-methyl-4-substitutedphenyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylic acid ethyl esters proficiently in high yields.     

Synthesis of ethyl alkylidene alpha cyanoacetates under ultrasound irradiation

Condensation of ketones with ethyl cyanoacetate catalysed by ammonium acetate-acetic acid results in ethyl alkylidene alpha cyanoacetate in 31-89% yield under ultrasound irradiation.     

Synthesis of functionalized 5-imino-2,5-dihydro-furans through the reaction of isocyanides with activated acetylenes in the presence of ethyl bromopyruvate

Summary The reaction between alkyl(aryl) isocyanides and dibenzoylacetylene in the presence of ethyl bromopyruvate leads to ethyl 3,4-dibenzoyl-2-bromomethyl-5-alkyl(aryl)imino-2,5-dihydro-furan-2-carboxylates in high yields. Dialkyl acetylenedicarboxylates react with tert-butyl isocyanide and ethyl bromopyruvate to produce 3,4-dialkyl 2-ethyl 2-bromomethyl-5-tert-butylimino-2,5-dihydro-furan-2,3,4-tricarboxylates.     

Synthesis of ethyl α-cyanocinnamates under ultrasound irradiation

Knoevenagel condensation of ethyl cyanoacetate with aromatic aldehydes catalyzed by pyridine results ethyl α-cyanocinnamates in 80–96% yields under ultrasound irradiation.     

Molecular force fields of ethyl bromide: Normal coordinate analysis of d0, d2, d3, and d5 species

A normal coordinate analysis of ethyl bromide and some deuterated derivatives was carried out using the MUBFF and GHFF fields. The results are discussed in relation to the recently published force field of ethyl chloride.     

胡椒酸乙酯与牛血清白蛋白的相互作用及金属离子的影响

采用荧光光谱研究了胡椒酸乙酯与牛血清白蛋白(BSA)的相互作用。实验结果表明:胡椒酸乙酯与BSA形成基态复合物从而猝灭BSA的内源性荧光,猝灭原因主要为静态猝灭和非辐射能量转移作用。胡椒酸乙酯对BSA的猝灭速率常数Kq为1.451×1013L.mol-1.s-1(25℃)和1.136×1013L.mol-1.s-1(37℃),胡椒酸乙酯与BSA的结合常数KA为9.484×105L.mol-1(25℃)和1.355×106L.mol-1(37℃),结合位点数n为1.18(25℃)和1.24(37℃)。根据Frster偶极-偶极非辐射能量转移理论得到结合距离r为2.68 nm(25℃)和2.81 nm(37℃)。通过热力学参数的计算,确定胡椒酸乙酯与牛血清白蛋白的相互作用是熵增加和吉布斯自由能降低的自发过程,主要作用力为疏水作用力。讨论了共存金属离子对胡椒酸乙酯与BSA的相互作用的影响。     

On the laminar flame propagation of C5H10O2 esters up to 10 atm: A comparative experimental and kinetic modeling study

Biodiesel is a family of renewable engine fuels with carbon-neutral nature. In this work, three C₅H₁₀O₂ esters (methyl butanoate, methyl isobutanoate and ethyl propanoate), which can serve as model compounds of biodiesel and represent linear and branched methyl esters and linear ethyl esters, were investigated to characterize their laminar flame propagation characteristics up to 10 atm and unravel the effects of isomeric fuel structures. A high-pressure constant-volume cylindrical combustion vessel was used to achieve laminar burning velocity measurements at 1–10 atm, 423 K and equivalence ratios of 0.7–1.5, while comparative experimental work was performed on a heat flux burner at 1 atm, 393 K and equivalence ratios of 0.7–1.6 for methyl butanoate and ethyl propanoate. The laminar burning velocity generally decreases with increasing pressure and increases in the order of methyl isobutanoate, methyl butanoate and ethyl propanoate, which shows distinct fuel isomeric effects. A kinetic model of C₅H₁₀O₂ esters was developed and validated against the new data in this work and previous data in literature. Modeling analyses were performed to provide insight into the fuel-specific flame chemistry of the three esters isomers. Remarkable differences in radical pools of three ester isomers are concluded to be responsible for the observed fuel isomeric effects on laminar flame propagation. The feature of two ethyl groups connected to the ester group in ethyl propanoate facilitates the ethyl production and inhibits the methyl and allyl production, making it propagate fastest among the three isomers. The branched structure feature of methyl isobutanoate with methyl and i-propyl groups connected to the ester group prevents the ethyl formation and results in considerable CH₃ and allyl production, which decelerates its laminar flame propagation.     

基于SERS与PCA-SLR实现乙基对氧磷定量检测

利用表面增强拉曼光谱(SERS),结合主成分分析(PCA)与分段线性回归(SLR)算法实现乙基对氧磷的定量检测。首先采集820～1 630 cm-1乙基对氧磷溶液SERS,并对820～1 630 cm-1(全范围)与845～875 cm-1(特征范围)光谱分别进行标准正态变换(SNV)、多元散射校正(MSC)、一阶导数绝对值、二阶导数等预处理;然后经PCA降维后利用SLR建立乙基对氧磷溶液浓度预测模型。通过对比不同模型的预测准确度,发现特征范围光谱采用MSC预处理后所建立的模型为最优,总体预测均方误差值(RMSEP)为0.33,满足乙基对氧磷定量检测的需要。     

High- and low-temperature ignition delay time study and modeling efforts on vinyl acetate

Although esters in general have received much attention over the last decade of combustion research, the combustion of vinyl esters have yet not been studied in detail. Recent studies on ethyl acetate show that vinyl acetate is a major intermediate but its combustion is not well understood. This may be due to the fact that vinyl acetate itself can presumably not be used as a fuel or fuel additive, but both the fundamental understanding of vinyl ester combustion and the improvement of the ethyl ester modeling motivate the present study. Building on the work on ethyl acetate, a first kinetic model for the high- and low-temperature combustion of vinyl acetate is proposed, which includes reactions and intermediates that have not been considered before. These reactions are based on low-level quantum mechanical calculations as well as analogies drawn to mainly ethyl acetate. Seven additional species are considered compared to the ethyl acetate study for which the thermochemical data is derived by ab-initio calculations. The vinyl acetate kinetic model is validated against ignition delay times obtained in a shock tube and a rapid compression machine at pressures of 20 and 40 bar and temperatures ranging from 850 to 1250 K. Overall, a satisfactory agreement between the predictions of the kinetic model and the experimental data was found for all investigated conditions. Rate of production and brute force sensitivity analyses were performed to identify the most relevant reaction pathways, which underline the strong connection between the vinyl acetate and ethyl acetate chemistry.     

A one-pot synthesis of functionalized thiazoles from acid chlorides, secondary amines, ethyl bromopyruvate, and ammonium thiocyanate

An efficient one-pot synthesis of ethyl 2-(4-aryl-2-dialkylamino-1,3-thiazole-5-yl)-2-oxoacetates using acid chlorides, secondary amines, ethyl bromopyruvate, and ammonium thiocyanate is described.     

基于时间分辨荧光光谱法同时测定己酸乙酯与乙酸乙酯

提出了一种基于时间分辨荧光光谱分析法同时测定己酸乙酯和乙酸乙酯混合液中各组分浓度的方法。实验测得两种单体物质的荧光发射光谱重叠度达到78%。对于荧光发射光谱重叠度很高的物质使用普通荧光方法结合算法也很难进行定量分析。而通过量子化学计算结果,对两种单体的分子结构分析,得到己酸乙酯的荧光寿命长于乙酸乙酯。通过时间分辨荧光光谱测量得到己酸乙酯和乙酸乙酯的荧光寿命分别为1.0和5.3 ns。两种物质的荧光发射光谱重叠严重,但是其荧光衰减曲线有明显的差别,所以提出使用时间分辨荧光光谱法对两种物质进行定量分析。通过分析两种物质不同体积比下的荧光衰减曲线的变化趋势,建立两种物质体积比的预测模型,并对其进行检验。实验结果表明：该方法能够实现混合溶液中各组分体积比的测量,其测量的平均残差控制在1%以内,具有一定的实用价值。     

2,2-二甲基-3-(2,2-二氯乙烯基)环丙烷羧酸乙(甲)酯及其合成中间体的结构测定

由异戊烯醇-原乙酸三乙（甲）酯法相继合成了拟除虫菊酯类农药中间体3，3-二甲基-4-戊烯酸乙（甲）酯，4，6，6，6-四氯-3，3-二甲基己酸乙（甲）酯和2，2-二甲基-3－（2，2-二氯乙烯基）环丙烷羧酸乙（甲）酯等化合物，对这些化合物进行了元素分析、红外光谱、1HNMR等测定，与文献结果相符，为了进一步明确结构，测定了未见报道的13CNMR，给出了波谱数据归属．     

Structural Orientations of Cellulose Acetate Phthalate/Ethyl Cellulose Blends in Solution

Cellulose acetate phthalate/ethyl cellulose blends were investigated by means of attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), thermogravimetry/differential thermal analysis (TGA-DTGA), shear viscosity and oscillatory shear tests. The studies showed a higher thermal stability, induced by the occurrence of hydrogen bonding, more predominant in ethyl cellulose and blends with higher content of ethyl cellulose. The effect of solution concentrations in N,N-dimethylacetamide, blend compositions and shear rate on the rheological functions generated regions with properties typical for liquid crystalline solutions in the shear field. These studies are suggested to be useful in identification of liquid crystal properties, required in some electrotechnical applications.     

氯嘧磺隆标准品的提纯与表征

以重结晶,柱晶析方法对合成的氯嘧磺隆提纯,并进行了定值分析及定性表征,结果表明,所研制的标准品纯度达99％以上。     

Reaction kinetics investigation of 1‐fluoro‐2,4‐dinitrobenzene with substituted anilines in ethyl acetate–methanol mixtures using linear and nonlinear free energy relationships

Aromatic nucleophilic substitution reaction of 1‐fluoro‐2,4‐dinitrobenzene with para‐substituted and meta‐substituted anilines was kinetically investigated in the mixtures of ethyl acetate and methanol at room temperature. The correlation of second‐order rate coefficients with Hammett's substituent constants yields a fairly linear straight line with negative slope in different mole fractions of ethyl acetate–methanol mixtures. The measured rate coefficients of the reaction demonstrated a dramatic variation in ethyl acetate–methanol mixtures with the increasing mole fraction of ethyl acetate. Linear free energy relationship (LFER) investigations confirm that polarity has a major effect on the reaction rate whereas the hydrogen‐bonding ability of the media has a slight effect on it. Nonlinear free energy relationship based on preferential solvation hypothesis showed differences between the microsphere solvation of the solute and the bulk composition of the solvents, and non‐ideal behavior is observed in the trend of the rate coefficients, which cover the LFER results. Copyright © 2011 John Wiley & Sons, Ltd.     

紫外分光光度法测定废水中的乙基黄原酸钾

乙基黄原酸钾在301nm处有最大吸收峰.在酸性条件下,乙基黄原酸钾能迅速分解,同时其吸收峰消失.根据此特性,可采用紫外分光光度法测定生产废水中乙基黄原酸钾的含量.以待测废水样作背景校正,可以有效的消除干扰.该方法的检出限为0.01mg/L,方法的线性范围为0.04-18mg/L.水样测定的相对标准偏差为1.63%.加标...     

H4SiW12O40/SiO2催化合成庚酸乙酯

以H4SiW12O40/SiO2为催化剂,庚酸和无水乙醇为原料,合成酒用香料庚酸乙酯。结果表明,复合硅钨杂多酸是合成庚酸乙酯的良好催化剂,适宜的工艺条件为：酸醇物质的量比为1∶2,催化剂用量3%,甲苯做带水剂8mL,反应时间2.5h,在此条件下产率可达49.5%。