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合成乳酸乙酯精馏残液的分析张青枝,华国雄,鲁富贵,张深松,赵根锁(河南师范大学化学系新乡453002)(河南省化学研究所郑州)关键词乳酸乙酯,精馏残液,红外光谱,电子轰击质谱采用乳酸、乙醇直接酯化法[1],有机溶剂共沸法[2],合成乳酸乙酯收率较低。... 相似文献
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报道了实验室可行、工业生产实用的l-对甲苯磺酸乳酸乙酯产率的分析方法,采用K2CrO4-K2Cr2O7混合指示剂,其最佳配比为K2CrO4:K2Cr2O7=6:1(质量比),体系的最佳pH为5.8,测得l-乳酸乙酯与对甲苯碘酰氯反应制备和的l-对甲苯磺酰乳酸乙酯的产率为94.0%。 相似文献
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建立了采用 K2 Cr O4 - K2 Cr2 O7混合指示剂测定 L-对甲苯磺酰乳酸乙酯合成物产率的化学分析方法 ,K2 Cr O4 - K2 Cr2 O7的最佳配比为 K2 Cr O4 ∶ K2 Cr2 O7=6∶ 1 (m/m) ,体系的最佳酸度为 p H5.8,测得 L-乳酸乙酯与甲苯磺酰氯反应制备的 L-对甲苯磺酰乳酸乙酯的产率为 94.0 %。 相似文献
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食醋中C1—C8脂肪酸及乳酸的气相色谱分析 总被引:2,自引:0,他引:2
食醋中C1-C8脂肪酸和乳酸与适当过量的四甲基氢氧化铵作用生成季胺盐,用二甲基甲酰胺将其溶解,在室温下与过量溴乙烷完全反应而生成相应的乙酯。生成的乙酯在10%丁二酸乙二醇聚酯(PGS)柱上进行分离。用保留时间定性,用内标法定量。本法操作简便、快速,分离完全,对几种样品的测定结果较好。 相似文献
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以氧化改性活性炭为载体,用浸渍法制备了系列VOSO4/活性炭催化剂(VO/ACO). 采用FT-IR、XRD、ICP和比表面及孔结构测定等表征了催化剂组成与结构. 考察了VO/ACO催化剂在常压分子氧氧化乳酸乙酯中的催化作用. 结果表明, 氧化活性炭是氧钒催化剂的有效载体,以pH=3的VOSO4溶液浸渍得到的VO-3/ACO催化剂具有优良的催化性能, 在二氯乙烷中常压,80 ℃ 反应18 h, 乳酸乙酯转化完全, 丙酮酸乙酯的选择性达95.2%. 催化剂重复使用三次后的性能基本保持不变. 相似文献
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Richard R. Schrock 《Journal of organometallic chemistry》1976,121(3):373-379
MMe5(dmpe) (M = Nb or Ta, dmpe = Me2PCH2CH2PMe2) reacts with H2 (500 atm) and dmpe in THF at 60°C to give MH5(dmpe)2? NbH5(dmpe)2 readily reacts with two mol of CO or ethylene (L) to give NbHL2(dmpe)2. The exchange of the hydride ligand with the ethylene protons in NbH(C2H4)2(dmpe)2 is not rapid on the 1H NMR time scale (60 MHz) at 95°C. 相似文献
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一些具有NASICON型网格结构的固体电解质具有高的电导率和好的稳定性,NASICON的意思是Na Super Ionic Conductor[1]。当NaZr2(PO4)3中P5 被Si4 部分取代时便可以得到具有NASICON结构的Na1 xZr2SixP3-xO12体系,其具有高的钠离子电导率。然而有相同结构的Li1 xZr2SixP3-xO12体系的离子电导率却很低,这是因为Li 半径太小,而NASICON三维网格结构的离子通道太大,两者不匹配而使电导率下降[2]。但当LiZr2(PO4)3中Zr4 被离子半径小些的Ti4 取代,所得LiTi2(PO4)3的通道就与Li 半径相匹配,适合于锂离子的迁移,从而使其电导率… 相似文献
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Zh. S. Shukurov S. S. Ishankhodzhaev M. K. Askarova S. Tukhtaev 《Russian Journal of Inorganic Chemistry》2010,55(10):1630-1633
The solubility in the NaClO3 · 2CO(NH2)2-NH2CH2CH2OH-H2O system was studied over the range from the complete solidification temperature (−54.8°C) to 60°C. A polythermal solubility
diagram was constructed where the regions of crystallization of ice, carbamide, sodium dicarbamidochlorate, monoethanolamine
dihydrate, monoethanolamine monohydrate, and anhydrous monoethanolamine were demarcated. The system is a simple eutonic. 相似文献
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Glasses with the compositions 50.9 SiO2 · 20.8 Al2O3 · (20.8 ? x) MgO· × ZnO · 3.7 TiO2 · 3.7 ZrO2 with x = 0, 2.3, 4.6 and 9.3 were annealed at temperatures in the range from 850 to 1100 °C. Depending on temperature, high- or low-quartz solid solutions, magnesium aluminosilicate, mullit and spinel precipitated. These glass–ceramics exhibit excellent mechanical properties and are potential candidates for applications in micromechanics or as hard disc substrate.The larger the ZnO concentration, the lower is the glass transition temperature. Also microhardnesses and Young’s moduli increased with increasing ZnO concentration. The nucleation temperature was of minor importance. To achieve good mechanical properties, the initially formed high-quartz phase must transform to the corresponding low-quartz phase. This occurs if the quartz phase contains only minor MgO or ZnO concentrations, which can be achieved by increasing the annealing times or temperature. Then MgO, ZnO and Al2O3 occur as separate spinel or gahnite phase. 相似文献
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Ai-Min Zhu Qi Sun Jin-Hai Niu Yong Xu Zhi-Min Song 《Plasma Chemistry and Plasma Processing》2005,25(4):371-386
An experimental study on the conversion of NO in the NO/N2, NO/O2/N2, NO/C2H4/N2 and NO/C2H4/O2/N2 systems has been carried out using dielectric barrier discharge (DBD) plasmas at atmospheric pressure. In the NO/N2 system, NO decomposition to N2 and O2 is the dominating reaction; NO conversion to NO2 is less significant. O2 produced from NO decomposition was detected by an on-line mass spectrometer. With the increase of NO initial concentration, the concentration of O2 produced decreases at 298 K, but slightly increases at 523 K. In the NO/O2/N2 system, NO is mainly oxidized to NO2, but NO conversion becomes very low at 523 K and over 1.6% of O2. In the NO/C2H4/N2 system, NO is reduced to N2 with about the same NO conversion as that in the NO/N2 system but without NO2 formation. In the NO/C2H4/O2/N2 system, the oxidation of NO to NO2 is dramatically promoted. At 523 K, with the increase of the energy density, NO conversion increases rapidly first, and then almost stabilizes at 93–91% of NO conversion with 61–55% of NO2 selectivity in the energy density range of 317–550 J L−1. It finally decreases gradually at high energy density. A negligible amount of N2O is formed in the above four systems. Of the four systems studied, NO conversion and NO2 selectivity of the NO/C2H4/O2/N2 system are the highest, and NO/O2/C2H4/N2 system has the lowest electrical energy consumption per NO molecule converted. 相似文献
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H.J. Breunig O. Moldovan U. Rosenthal R.A. Varga 《Journal of organometallic chemistry》2011,696(2):523-526
Reactions of [Cp2Ti(btmsa)] (btmsa = bis(trimethylsilyl)acetylene) with R4Sb2 (R = Me, Me3Si) give [Cp2TiSbMe2]2 (1) or [Cp2TiSb(SiMe3)2]2 (2) respectively. [Cp2TiCl]2·2Mes4Sb2 (3) is serendipitously formed from [Cp2Ti(btmsa)] and Mes2SbH containing NH4Cl traces. 相似文献
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phase diagrams of KCl-KBO2-K2CO3, K2MoO4-KBO2-K2CO3, and K2WO4-KBO2-K2CO3 ternary systems were studied by a calculation-experimental method and differential thermal analysis (DTA). The coordinates
of ternary eutectics were determined to be E
1: 622°C, 8.5 mol % KBO2, 56.5 mol % KCl, and 35 mol % K2CO3; E
2: 710°C, 23 mol % KBO2, 43 mol % K2CO3, and 34 mol % K2MoO4; E
3: 710°C, 23 mol % KBO2, 43 mol % K2CO3, and 34 mol % K2WO4. The specific heats of melting of the eutectics were determined. 相似文献
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Hueso JL Gonzalez-Elipe AR Cotrino J Caballero A 《The journal of physical chemistry. A》2007,111(6):1057-1065
In this paper, continuing previous work, we report on experiments carried out to investigate the removal of NO from simulated flue gas in nonthermal plasmas. The plasma-induced decomposition of small concentrations of NO in N2 used as the carrier gas and O2 and CH4 as minority components has been studied in a surface wave discharge induced with a surfatron launcher. The reaction products and efficiency have been monitored by mass spectrometry as a function of the composition of the mixture. NO is effectively decomposed into N2 and O2 even in the presence of O2, provided always that enough CH4 is also present in the mixture. Other majority products of the plasma reactions under these conditions are NH3, CO, and H2. In the absence of O2, decomposition of NO also occurs, although in that case HCN accompanies the other reaction products as a majority component. The plasma for the different reaction mixtures has been characterized by optical emission spectroscopy. Intermediate excited species of NO*, C*, CN*, NH*, and CH* have been monitored depending on the gas mixture. The type of species detected and their evolution with the gas composition are in agreement with the reaction products detected in each case. The observations by mass spectrometry and optical emission spectroscopy are in agreement with the kinetic reaction models available in literature for simple plasma reactions in simple reaction mixtures. 相似文献
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W. Li M. Wang Z. H. Li X. F. Shang H. Wang Y. W. Wang Y. B. Xu 《Russian Journal of Electrochemistry》2007,43(11):1279-1283
The lithium-ion-conducting inorganic solid electrolytes in the oxide systems Li2O-SiO2-P2O5 and Li2O-TiO2-SiO2-P2O5 were prepared by the solid-state reaction, and the electrolyte pellet made by cold-pressing method had diameter of 13 mm
and was about 1 mm thick. Phase identification and surface morphology of the products were carried out by X-ray diffraction
and scanning electron microscopy. Ionic conductivity of the pellets was investigated through ac impedance. The results show
that the adding of other cations can improve the ionic conductivity of the solid electrolyte, and the sintering temperature
and duration can influence the ionic conductivity. The maximum ionic conductivity in the samples is 9.9 × 10−4 S/cm in the Li2O-TiO2-SiO2-P2O5 system.
Original Russian Text ? W. Li, M. Wang, Z.H. Li, X.F. Shang, H. Wang, Y.W. Wang, Y.B. Xu, 2007, published in Elektrokhimiya,
2007, Vol. 43, No. 11, pp. 1341–1345. 相似文献
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本文利用一种具有H_2O_2催化活性的Cu-MOF[Cu_3(BTC)_2(H_2O)_3,简称HKUST-1],构建了以邻苯二胺(OPD)为颜色指示分子的比色传感体系,实现了对H_2O_2和多巴胺(DA)的快速灵敏检测。HKUST-1起到催化H_2O_2氧化OPD的作用,反应体系能够呈现出显著的颜色变化。在优化条件下,415nm处的吸收峰强度与H_2O_2浓度呈双线性关系,线性范围分别为10~50 mmol/L和50~100 mmol/L,相对标准偏差分别为0.9947和0.9995,最低检出限为1.29mmol/L。由于DA能抑制H_2O_2氧化OPD,因此比色传感体系还可以用于快速检测DA,线性范围分别为0.25~5μmol/L和2.5~25μmol/L,相对标准偏差分别为0.9783和0.9705,最低检出限为0.262μmol/L。该项工作拓展了Cu-MOFs材料在生物分子催化和生物传感方面的应用。 相似文献