液相色谱-质谱法分析季戊四醇油酸酯

提出了高效液相色谱-质谱法测定单、双季戊四醇油酸酯中单酯、双酯、三酯和四酯的含量。样品经正己烷-异丙醇(9+1)溶剂溶解后,以Lichrospher Si100-5色谱柱(4.6mm×250mm,5μm)为分离柱,以不同体积比的正己烷和异丙醇混合溶液为流动相梯度淋洗。采用总离子流图的峰面积归一化法对单、双季戊四醇油酸酯中单酯、双酯、三酯和四酯的含量进行定量,用质谱法做鉴别。     

高效液相色谱/电喷雾质谱联用分析乙二醇硬脂酸酯

乙二醇硬脂酸酯和乙二醇双硬酯酸酯是日化工业中常用的珠光剂,被广泛地应用在丝毛洗涤剂、液体洗涤剂和护发用品等领域,对提高产品的性能和外观起到了良好的作用。样品中单双酯的相对含量和碳数分布对其使用性能有较大的影响,会直接影响到产品的稳定性,外观等。乙二醇硬脂酸酯的测定常用化学分析方法,测定其皂化价,酸价等指标^[1],从而间接估计其在样品中的含量,但无法测定样品中单双酯的相对含量和碳数分布情况。用高效液相色谱法,使用正相硅胶柱和四氢呋喃流动相,可以实现乙二醇单硬脂酸酯和乙二醇双硬脂酸酯的分离,但由于乙二醇硬脂酸酯无紫外吸收,需要用到示差折光检测器,无法实施梯度洗脱优化分离,该方法只能按单双酯分离,不能按碳数分离。用高温毛细管柱也可以直接进行乙二醇硬脂酸酯的气相色谱分析^[2]。本研究应用非反相高效液相色谱法,以大气压电离质谱为其在线检测器,同时实现单双酯的分离和按碳数的分离。     

甲基丙烯酸二缩三乙二醇双酯的氧化及其厌氧胶吸氧的研究

甲基丙烯酸缩乙二醇双酯,作为一种双官能基单体,是配制厌氧胶的主要组分,本文研究了室温和70±2℃下甲基丙烯酸二缩三乙二醇双酯(双酯)的氧化,以及DMT、CHPO、糖精、对苯二酚、草酸、铜离子等对双酯氧化的影响,发现DMT、铜离子明显加速双酯氧化,而对苯二酚、草酸抑制双酮氧化,与DMT共存时,糖精对氧化亦起加速作用。 此外,本文研究了厌氧胶与吸氧的关系,发现厌氧胶是一个不断吸氧的体系,厌氧胶中各组分对双酯吸氧与稳定性的影响与它们对双酯氧化的影响基本上是平行的,即DMT与铜离子促进双酯吸氧并降低稳定性,草酸抑制吸氧并增加稳定性,CHPO和糖精对双酯吸氧和稳定性影响比较小,但有DMT存在时,糖精则明显起加速作用。     

枞酸乙二醇单酯与双酯的合成工艺研究

采用L39^4正交实验研究了枞酸乙二醇单酯与双酯的合成工艺。探讨了反应温度、催化剂用量、反应物料摩尔比、反应时间等诸因素对转化率及选择性的影响。结果表明：反应温度与反应物料摩尔比分别对转化率及选择性具有最显著的影响。实验提供了枞酸乙二醇单酯与双酯的优化合成条件,在此基础上以松香为原料进行了验证。     

制备失水山梨醇单油酸酯的选择性酯化反应研究

研究了几种酸性催化剂(H2SO4、H3PO4、CH3C6H4SO3H)、碱性催化剂(NaOH、Na2CO3、NaHCO3)和氧化物(ZnO、Al2O3、TiO2)对山梨醇和油酸的催化酯化反应.结果表明用酸性催化剂催化的酯化反应产品中的双油酸酯的比例较高;用碱性催化剂或氧化物催化剂催化的酯化反应产品中的单油酸酯的比例较高,其中用ZnO催化所得产品中的单油酸酯的比例可达91%.     

甲基丙烯酸缩乙二醇双酯、甲基丙烯酸三羟甲基丙烷三酯的制备

甲基丙烯酸缩乙二醇双酯(简称双酯)、甲基丙烯酸三羟甲基丙烷三酯(简称三羟三酯)是常用的烯类聚合交链剂,在制备感光树脂板、厌氧粘合剂、齿科用复合充填树脂等方面已获得广泛应用。双酯、三羟三酯的制备方法分直接酯化和酯交换两种。直接酯化是甲基丙烯酸与相应的醇在硫酸、苯     

乙二醇二丙酸酯的合成与溶剂性能研究

以乙二醇二丙酸酯为重点,研究了乙二醇二羧酸酯的合成与性能。用乙二醇和丙酸直接酯化合成乙二醇二丙酸酯,在单因素实验的基础上,用正交法探讨较佳合成条件。采用红外、核磁对产物进行表征。结果表明,n(丙酸)∶n(乙二醇)=2.5∶1,对甲苯磺酸和甲苯分别占反应物总质量的1.0%和10%,反应时间3 h,乙二醇二丙酸酯收率可达87.4%。并结合其他乙二醇二羧酸酯,通过与常见高沸点溶剂性能的比较分析,表明该产物溶解力强,相对环保安全,在涂料、塑料等工业中具有潜在的应用价值。     

（甲基）丙烯酸酯类互贯网络聚合物IPN的交联剂甲基丙烯酸类多甘醇双酯的研究

首次用价廉，易于合成的甲基丙烯酸的乙二醇双酯，三甘醇双酯替代三缩四乙二醇双酯用作互贯网络聚合物中（甲基）丙烯酸类的交联剂，合成了相应的互贯网络聚合物。对反应动力学和ＩＰＮ的动态力学性能，形态结构进行了讨论，获得满意结果。ＩＰＮ用作阻尼材料，能降低噪声振幅６倍以上。     

烯烃与双烯烃共聚合物反应机理.Ⅷ.红外光谱定量法观察双甲基丙烯酸乙二醇酯聚合过程中悬挂双键的变化

本文是用红外光谱测定双甲基丙烯酸乙二醇酯在交链聚合反应中,凝胶点以后悬挂双键含量的变化。在测定中用1630cm~(-1)和945cm~(-1)作为分析谱带。     

熔化提取-毛细管气相色谱法测定乙二醇硬脂酸酯中乙二醇的残留量

提出了毛细管气相色谱法测定乙二醇硬脂酸酯中乙二醇残留量的方法。样品在50℃熔化,经甲醇超声浸提,以丙二醇为内标,采用HP-5毛细管色谱柱分离,用火焰离子化检测器测定。乙二醇的质量浓度在102.6~1 026.0 mg.L-1范围内呈线性,方法的检出限(3S/N)为30 mg.L-1。应用此方法分析乙二醇硬脂酸酯,回收率在93.7%~103.2%之间。     

Synthesis of glycol diesters through the depolymerization of polyethylene glycols with carboxylic acids using a proton-exchanged montmorillonite catalyst

A convenient and sustainable method for the synthesis of glycol diesters was developed through the depolymerization of polyethylene glycols (PEGs) with carboxylic acids using proton-exchanged montmorillonite as an efficient solid acid catalyst. Several functionalized glycol diesters were obtained in good yields from PEGs and readily available carboxylic acids. Upon reaction completion, the catalyst could be easily separated by filtration and reused with its activity remaining unchanged.     

杂多酸对二甘醇脱水环化反应的催化作用

研究了杂多酸对二甘醇脱水环化的催化作用。结果表明,磷钨酸,硅钨酸,硅钼酸具有较高的催化活性,而磷钼酸的催化活性较低。采用ＴＧ,ＩＲ,ＧＣ－ＭＳ,电导等测试技术,对正丁胺酸性,杂多阴离子碱度,还原特性的测定及对产物结构的分析。     

Determination of Polyethylene Glycol Monoester Acrylate and Polyethylene Glycol Diester Acrylate Using Reversed-Phase High-Performance Liquid Chromatography

A procedure was developed for the determination of polyethylene glycol monoester acrylate (PEGMA) and polyethylene glycol diester acrylate (PEGDA) by reversed-phase high performance liquid chromatographic (RP-HPLC) with UV detector. Sample was well separated on an SinoChrom ODS-BP (C-18) column (200 × 4.6 mm i.d., 5 μm) with mobile phases composed of acetonitrile-phosphate buffer solution (0.05 mol · L^?1 pH = 6.86) in the ratio of 42:58 (v/v). The PEGMA and PEGDA were detected by UV detector at 205 nm, and quantitatively analyzed with an external standard of methyl acrylate. For PEGMA, the linear response ranged from 0.40 × 10^?5 mol · L^?1 to 2.00 × 10^?3mol · L^?1 (r² > 0.999), the detection limit was 0.12 × 10^?5 mol · L^?1, the recovery rate was found to be 93.4%–99.7%. For PEGDA, the linear response ranged from 0.20 × 10^?5 mol · L^?1 to 1.00 × 10^?3mol · L^?1 (r² > 0.999), the detection limit was 0.04 × 10^?5 mol · L^?1, the recovery rate was found to be 99.1% ～ 105.8%. This quantitative method can also be used in the HPLC analysis of other α,β-unsaturated esters.     

Amino Acid and Poly(Ethylene Glycol) Based Self-Organizing Polymeric Systems: Chemo-Enzymatic Synthesis and Characterization

A chemo/regio selective enzymatic methodology has been designed to synthesize amphiphilic copolymers based on amino acid diesters and poly(ethylene glycol) [PEG]. The condensation polymerization was catalyzed by immobilized Candida antarctica lipase B (Novozyme 435) under solvent-less conditions. The synthesized polymers 3a–c were derivatized with long chain acid chlorides by chemical acylation to get the amphiphilic polymers 4a–c. The physical properties of the synthesized amphiphilic polymers viz: aggregation number, critical micelle concentration (CMC), radius of gyration (R_g), hydrodynamic radius (R_h) and particle size distribution were studied by static and dynamic light scattering (SLS and DLS) techniques. The polymers were found to be promising in drug delivery applications.     

Measurement of oleic acid in human plasma by isotope dilution mass spectrometry

Summary A method for the quantitative determination of oleic acid in human plasma by isotope-dilution mass spectrometric technique is described. For the measurement of the fatty acid concentration (1-¹³C) oleic acid is added to the plasma sample. The fatty acids are extracted with n-hexane. Portions of the extract are esterified by the boron trifluoridemethanol method or stable isotope methylation. The methyl ester derivatives of the fatty acids are separated and detected by GC-MS with the mass spectrometer set to m/z 296 and 297. For the measurement of oleic acid after stable isotope methylation the m/z 299 and m/z 300 are monitored. The amounts of oleic acid in the plasma are calculated from the isotope ratios measured by selected ion monitoring. The recovery of the methylation step and the precision and accuracy of the GC-MS method are presented and discussed.     

扁桃油中脂肪酸组成的GC-MS法分析

以正己烷为提取剂,采用超声法提取油脂,经KOH-甲醇甲酯化处理后,以气相色谱-质谱(GC-MS)联用技术鉴定出陕西蒲城3个品种扁桃油中的脂肪酸主要组成为:油酸、亚油酸、9-十六碳烯酸、硬脂酸、棕榈酸,其中不饱和脂肪酸总量占91.4%以上,主要成分油酸占73.3%以上。     

油酸新戊二醇己二酸复合酯的合成及其润滑性能

新戊二醇(NPG)和己二酸(AA)通过酯化反应合成了"低聚物"中间体(1).当n(NPG):n(AA)＝1.5～3.0时,1的聚合度(m)在4.34～2.10,收率97%.以对甲苯磺酸为催化剂,甲苯为带水剂,1与油酸进行酯化得到复合酯(2),收率83%～89%.测定了2的黏度、黏度指数、氧化稳定性、生物降解率、摩擦磨损性能和热稳定性.结果表明,2的黏度和氧化稳定性随着m的增大而增大,100 ℃时的黏度在18.3 mm~2·s~(-1)～30.1 mm~2·s~(-1),黏度指数均超过200,凝点低于-43 ℃,生物降解率＞96%,最大无卡咬负荷(P_B)为784 N,磨斑直径0.40 mm,热分解温度＞300 ℃.1和2的结构经IR表征.     

Catalytic Zinc Complexes for Phosphate Diester Hydrolysis

Creating efficient artificial catalysts that can compete with biocatalysis has been an enduring challenge which has yet to be met. Reported herein is the synthesis and characterization of a series of zinc complexes designed to catalyze the hydrolysis of phosphate diesters. By introducing a hydrated aldehyde into the ligand we achieve turnover for DNA‐like substrates which, combined with ligand methylation, increases reactivity by two orders of magnitude. In contrast to current orthodoxy and mechanistic explanations, we propose a mechanism where the nucleophile is not coordinated to the metal ion, but involves a tautomer with a more effective Lewis acid and more reactive nucleophile. This data suggests a new strategy for creating more efficient metal ion based catalysts, and highlights a possible mode of action for metalloenzymes.     

C18 tetraynoic fatty acids and essential oil composition of Mkilua fragrans

The fatty acids 17,18-dihydroxyoctadeca-9,11,13,15-tetraynoic acid (mkiluaynoic acid A) and 18-hydroxyoctadeca-9,11,13,15-tetraynoic acid (mkiluaynoic acid B), 5,7,3',4'-tetrahydroxyflavanol, 3,4-dihydroxybenzoic acid and a mixture of stearic and oleic acids were isolated from fruits and stem barks of Mkilua fragrans (Annonaceae). Mkiluaynoic acid A exhibited antifungal activity against Candida albicans comparable with that of the standard antifungal agent Ketoconazole. Structural determination was achieved by analysis of spectroscopic data. The flower stalks yielded essential oils that mainly consisted of sesquiterpenoids as revealed by GC-MS analysis, whereby 14 sesquiterpenes and four other compounds were identified.     

Kinetic Modeling of Ethylene Glycol Monoesterification

The monoesterification of ethylene glycol under isothermal conditions was conducted using benzoic acid in methane‐sulfonic acid/Al₂O₃ as a catalyst. Using this reagent, glycol was selectively monoesterified with high yield. The reactions were performed within an automated batch reactor under equimolar conditions, constant rotational frequency of the stirrer, and within the temperature range from 65 to 85°C. The rate constant related to this reaction and to the corresponding reverse reaction, activation energy, and preexponential factor was derived from experimental data. It has been concluded that under these conditions the formation of dibenzoate was successfully prevented.