查询词典 esters

The method has been used to determine Phthalic esters in drinking water and seawater sample. 3. Single drop microextraction, followed by gas chromatography with flame ionization detection has been applied to determine Formaldehyde, Acetaldehyde and Acraldehyde in water based on 2,4-Dinitrophenylhydrazine derivatization. Extraction solvent, extraction time and stirrer speed were optimized. Optimal experimental conditions were as follows: 1.6μL toluene microdrop exposed for 30 min in a 3ml aqueous sample placed in 4ml vial and stirred at 600 rpm/min.

以2，4-二硝基苯肼衍生，单滴液相微萃取与气相色谱火焰光度检测器联用测定水样中的甲醛、乙醛、丙烯醛，考察了萃取溶剂、液滴大小、萃取时间、搅拌速度、盐效应等对该方法的影响，并对影响液相微萃取的各种因素进行了系统的阐述，确定了该体系的最佳实验条件，实现了甲醛、乙醛、丙烯醛的提取和富集。

In this paper, the synthesies and applications of phophonate esters, specially the syntheses and applications of a-aminoalkyl phosphonate esters have been re-viewed.

有机膦酸酯由于结构与性质的特殊性及广阔的应用前景，正在成为化学研究的热点。本文对有机膦酸酯及其衍生物，特别是α-氨基烷基膦酸酯的合成方法与应用做了介绍

So the bio (β-acryloxyl ethyl) esters of acrylic rosin (AR-2-HEA) with majorcomposition of bio-(β-acryloxyl ethyl) esters of acrylic pimaric acid were also prepared through acylchloridation and esterification.

同样采用酰氯化、酯化手段合成了丙烯酸松香酯，其主要组成为丙烯海松酸二酯。

Bycomprehensive use of phytochemical isolation methods, 37 compounds were isolated 5from the methnol-chloroform extract of P. telfairia, by methods of modern spectroscopy,six compounds' structures were elucidated, including 2 kinds of fatty acids, 2 kinds ofsterols and 2 kinds of are esters of sterol and fatty acids. Five of them were reported forthe first time on the chemical constituents' research of P. telfairia. Otherwise, weperformed GC-MS analysis of the volatile fraction in this extracts, the result revealedseveral constituents such as alkyl hydrocarbons and methyl esters of fatty acids.

综合利用各种植物化学分离手段，从海头红的甲醇-氯仿（1 ：1）提取物中分离到单体化合物 37 个，采用多种现代波谱技术手段鉴定了其中 6 个化合物的结构，包括 2 个脂肪酸类成分，2 个甾醇类成分，以及 2 个甾醇的脂肪酸酯，其中 5 个在海头红化学成分研究中为首次报道；另外还对该提取物的挥发性成分作了 GC-MS 分析，显示含有烷烃及脂肪酸甲酯等成分。

Mono dodecyl phosphate is synthesized using trichloro phosphate and di dodecyl phosphate is synthesized using phosphorous pentoxide. The structures are confirmed by IR and contents are analyzed by GC and HPLC. Mixed esters with different mass ratios of mono and di esters are prepared.

分别以三氯氧磷为磷酸化剂，合成并提纯了正十二烷基磷酸单酯，以五氧化二磷为磷酸化剂，合成并提纯正十二烷基磷酸双酯，其结构通过质谱得到了确证，产品组成采用气相色谱和高效液相色谱得到了确定。

The first step was esterifying FFA to its methyl esters. The second step was transesterifying the triglycerides in the products of the first step to methyl esters and glycerol.

第一步为酸催化预酯化反应，主要是将地沟油中的游离脂肪酸转化为脂肪酸甲酯；第二步为酸催化转酯化反应，主要是进一步将地沟油中的甘三酯转化为甲酯和甘油。

The compositions of fraction Ⅰ and Ⅱ were mainly petroleum acid methyl esters and aliphatic acid methyl esters with amide groups.

脂肪酸以C16和C18为主，单环环烷酸以C(下标 14~18)为主，四环环烷酸以C(下标 18~21)为主。

The dissociation constants and the reaction rate constants of inclusion complexes formed between α、β—cyclodextrin and several naphthyl esters (α—naphthyl acetate,β—naphthyl acetate,β—naphthyl caproate) were obtained by kinetics of hydrolyses of naphthyl esters.

通过几种脂肪酸萘酯(乙酸-α-萘酯、乙酸-β-萘酯、己酸-β-萘酯)的环糊精催化水解研究得到了它们同环糊精所形成的包接络合物的分解平衡常数和反应速度常数，进而提出了它们同环糊精所形成的包接络合物的结构模型。

Pure methyl esters were prepared using common oil plant seeds and the fatty acid composition of the achieved oil was measured by capillary column chromatography.The kinds and dosage of reagents for fast preparation of the methyl esters were investigated and the chromatographic conditions using two kinds of capillary columns were optimized.

本研究通过参考文献，直接使用常见油料植物种子制备纯油甲酯进行分析，探讨了快速制备甲酯的试剂选择及用量，强极性和弱极性的两种不同类型毛细管柱的最佳色谱分析条件，并将测定的主要脂肪酸含量与国家标准进行比较，结果较为一致，而且平行测定的相对标准偏差表明方法有较好的精密度和重复性。

Alcohols, ketones, esters, alcohols, ethers common media are methanol, ethanol, ethylene glycol, propanol, etc., ketones medium with acetone, methyl ethyl ketone, etc., there are a variety of methyl esters of medium, ethyl ester, ether medium with ether, ethyl ether, butyl ether, etc., they basically did not corrosive materials can be used for the specific use of the property should also be under the media and related requirements to make reasonable choices.

醇类、酮类、酯类、醚类常见的醇类介质有甲醇、乙醇、乙二醇、丙醇等，酮类介质有丙酮、丁酮等，酯类介质有各种甲酯、乙酯等，醚类介质有甲醚、乙醚、丁醚等，它们基本没有腐蚀性，常用材料均可适用，具体选用时还应根据介质的属性和相关要求做出合理选择。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。