查询词典 formaldehyde

In this paper, 2,2-dimethylolbutyraldehyde was synthesized through the acetal reaction of formaldehyde and butyraldehyde, using silicotungstic acid as catalyst.

通过实验研究了硅钨酸对此羟醛缩合反应的催化效果，研究探讨了硅钨酸对此缩醛反应的催化反应活性，以及催化剂的的用量，反应物配比，反应时间等因素对反应产品收率的影响，确定了最佳催化条件。

Another reason for this increasing interest is that formaldehyde and acetaldehyde are more available than propylene.

另一个原因，这越来越感兴趣的是，与比丙烯，甲醛和乙醛更容易利用。

The synthesis of acrolein by means of the catalytic vapor phase condensation of formaldehyde and acetaldehyde was studied.

利用冷凝甲醛和乙醛的气相催化法，来研究丙烯醛的合成。

The human exposure levels of formaldehyde and acetaldehyde in hospitals were discussed.

对医院甲醛、乙醛在人体内的暴露水平做了讨论，与其他类似场所相比，医院的暴露风险相对较小。

Formaldehyde, acetaldehyde and acrolein are common aldehyde in the environment.

甲醛、乙醛和丙烯醛均为环境中常见的醛类。

Some by-products are benzene, acetone, xylene, formaldehyde, and acetaldehyde.

一些副产品都是苯、丙酮、二甲苯、甲醛和乙醛。

Copper was reduced by formaldehyde which was contained in the effluent of chemical copper plating , and EDTA in the effluent was reclaimed after acidify.

探讨了利用原化学镀铜废液中的甲醛将铜还原，后酸化回收 EDTA的新工艺。

B3LYP/6-311++G** calculations were carried out to study the trimethylamine catalyzed Baylis-Hillman reaction between acraldehyde and formaldehyde.

采用密度泛函DFT-B3LYP方法在6-311++G**基组下计算研究了三甲胺催化的丙烯醛和甲醛的Baylis-Hillman反应的微观过程，获得了两种反应通道(分别对应于顺式-丙烯醛和反式-丙烯醛)的势能面。

The optimized structures and energies of the reactants, intermediates, transition states and products of two reaction channels (corresponding to syn-acraldehyde and anti-acraldehyde) in gas or in methanol solvent were obtained. The potential energy profiles reveal the processes of the trimethylamine-catalyzed Baylis-Hillman reaction between acraldehyde and formaldehyde in gas or in methanol solvent at the microscope level.

通过研究，获得了三种情况下两种反应通道(分别对应于顺式-和反式-丙烯醛)中涉及的反应物、产物、中间体、过渡态的优化结构及其能量，并由此得到了反应的势能面图，在电子微观层次上揭示了三甲胺催化的丙烯醛和甲醛的Baylis-Hillman反应的微观过程。

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。

Aquatic or marsh-growing fern allies; known to have existed since the Cenozoic; sometimes included in Lycopodiales.

生活于水中或湿地的蕨类；从新生代生存至今；有时归于石松目之中。

The engine was uprated from a 90hp Franklin to a 125hp Lycoming.

改良过的引擎是从90hp到125hp莱康明富兰克林。