查询词典 methanol

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 reaction process in methanol solvent can be deduced from the computational results with CPCM solvent model and the supermolecular handling, namely the reaction involves four steps in the methanol solvent. The nucleophilic addition of trimethylamine to acraldehyde generates an enolate. Nucleophilic attack of the enolate on the aldehyde forms the carbon-carbon bond, followed by the proton-transfer process and the further elimination generating the product and liberating the trimethylamine catalyst.

对于CH3OH对反应体系的影响，可以综合考虑CPCM溶剂模型及超分子模型下的研究结果，即CH3OH溶剂中反应按四步进行，催化剂三甲胺首先与丙烯醛发生亲核加成，生成的两性离子中间体与甲醛发生类似于Aldol的醛醇缩合，形成碳-碳键，之后发生分子内质子转移，最后经E1cb消除得到产物，并释放催化剂三甲胺。

Tetrachloroterephthalic acid was prepared by chlorinating terephthalic acid, oleumsolvent and iodine catalyst. Tetrachloroterephthalic acid was acylated by sulphurous oxychloride in the presence of DMF to form tetrachloroterephthaloyl chloride. The acyl chloride product was fluorinated by potassium fluoride and esterified by methanol to synthesize dimethyl tetrafluoroterephthalate. The ester was reduced with potassium borohydride and lithium chloride to give tetrafluoroterephthalyl alcohol. The above product was bromated in the hydrobromic acid to obtain 4-bromomethyl-2,3,5,6-tetrafluoro-benzene methanol. 4-Methyl-2,3,5,-6-tetrafluorobenzene ethanol was obtained by reducing the bromide with magnesium. In the exist of DCC and DMAP, tefluthrin was got by the condensation reaction between 4-methyl-2,3,5,6-tetrafluoro-benzene methanol and-(1RS,3RS)- 3-(2- chloro-3,3,3-trifluoro-1-propenyl)-2,2-dimethyl cycolpropanecar-boxylate acid.

对苯二甲酸与氯气在碘存在下以发烟硫酸为溶剂进行氯化制备四氯对苯二甲酸；再以DMF为催化剂与二氯亚砜反应生成四氯对苯二甲酰氯；以氟化钾为氟化剂，环丁砜为溶剂置换氟化，再与甲醇酯化得到四氟对苯二甲酸甲酯；以KBH4-LiCl为还原剂二甲醚为溶剂反应制得四氟对苯二甲基苄醇；以氯苯为溶剂在溴化氢溶液中溴化得到溴化产物；在乙醇溶液中经镁粉还原得到4-甲基-2，3，5，6-四氟苄醇；甲基苄醇与功夫酸在催化剂二环己基碳二亚胺和4-二甲氨基吡啶作用下缩合得到七氟菊酯，总收率达43.6%。

The first step reaction of methanol hydrochlorinate is methanol react with hedrogen chloride to produce monochloro methane and water, if the methanol can meet the request, the high pure monochloro methane can be refined.

甲醇法第一步反应为甲醇与氯化氢反应生成氯甲烷和水，如果所用原料甲醇满足要求，反应产物经过简单的精制即可得到高纯度的一氯甲烷。

The catalytic transformation pathway can change to decrease the yield of hydrogen and yield methyl-contained sulfides such as methyl mercaptan, dimethyl sulfide and dimethyl disulfide, but overlarge concentration of methanol would holdback the transformation of isobutyl mercaptan. The transformation of isobutyl mercaptan was favorable if the volume ratio of methanol and benzene was 0.2.The addition of methanol assume certain effect on the catalytic cracking of di-n-butyl sulfide in solvent benzene but without changing the cracking reaction mechanism of di-n-butyl sulfide.

甲醇也可以使异丁硫醇的催化转化路径发生改变降低硫化氢的产率，生成甲硫醇、甲硫醚及二甲基二硫化物等含甲基硫化物，但甲醇的浓度过高会抑制异丁硫醇的转化，在反应体系中当甲醇的体积占到溶剂苯体积的20%时对异丁硫醇的转化较为有利；甲醇的添加对丁硫醚在溶剂苯中的催化裂化有一定影响，但没有改变丁硫醚的裂解反应历程。

In order to improve the electro-catalytic activity of platinum based catalyst to methanol oxidation, in this thesis, firstly prepare heteropoly acid modified Pt/GC electrode with different concentration by cyclic voltammetry method, and then test the cyclic voltammetry curves individually in vitriolic and methanol solution. The study shows the best concentration for both phosphomolybdic acid and phosphotungstic acid is 1×10~(-3)mol/L. And find the more heteropoly acid modified on electrode, the lower peak-up potential towards methanol because of the existence of oxygenous species.

为了改善铂基催化剂氧化甲醇的催化活性，本论文首先通过循环伏安扫描法制备了不同浓度磷钼酸和磷钨酸修饰的Pt/GC电极，通过研究Pt/GC电极在修饰前后在硫酸溶液中及含甲醇的硫酸溶液中的循环伏安行为发现，磷钼酸和磷钨酸均能在PtRu/C电极上发生氧化还原反应，而且杂多酸修饰浓度对Pt/GC电极氧化甲醇的催化活性有很大影响。

We anticipate the demand of formaldehyde will up to 2,930,000 tons, and 1,320,000 tons of methanol will be consumed;② At present, the acetic acid mainly produced by food zymotechnics or ethane in our country, along with the development of synthesizing acetic acid process with methanol, the demand of methanol will increase rapidly.

预计2010年甲醛需求量将达到293万吨，届时消费甲醇达132万吨；②目前我国醋酸生产多采用粮食发酵法或乙烯法，随着甲醇羰基合成醋酸工艺的发展，对甲醇的需求将迅速增加。

Purified sucralose-6-acetate which had been recrystallized was hydrolyzed in th system of sodium methoxide/methanol solution, and the mixture was quenched with H+ ion exchange resin, and cake was washed with methanol. The eluate was concentrated to remove methanol and methyl acetate. The aqueous solution was decoloured with active carbon. The filtrate solution was concentrated and crystallized above 38℃for sever hours, the product sucralose was collected.

重结晶的三氯蔗糖-6-乙酸酯于CH3ONa/CH3OH体系中醇解，用H+型阳离子交换树脂中和，蒸去甲醇、乙酸甲酯等，在水相中用活性炭脱色，水溶液经浓缩，在38℃以上结晶数小时，分离得三氯蔗糖。

After washing with 3 mL of water and 3 mL of water-methanol (v/v, 60:40), the flavonoid fraction was eluted with 3 mL of methanol, dried under nitrogen, and dissolved in 0.05 mL of methanol.

清洗后的3毫升水和3毫升水，甲醇（五/五， 60：40 ），黄酮分数洗脱3毫升的甲醇，干燥氮气，并溶解于0.05毫升的甲醇。

The results showed: when TLC solvent system was: chloroform - methanol - diethyl amine = 90:9:1, alkaloids from lotus leaves were well isolated, and five components were isolated and identified by spraying Dragendorff reagent. The optimal conditions of HPLC solvent system were: methanol- water - diethyl amine = 75:25:0.0125. Under the conditions, components of alkaloids from lotus leaves were separated very well, and ideal RP-HPLC peaks were obtained.5、Methods of High Speed Counter Current Chromatography and preparative High Performance Liquid Chromatography applied to identify and purify alkaloids from lotus leaves were set up. When solvent system of HSCCC was: chloroform - methanol - water (pH=4.00)= 4:3:2, speed of chromatogram was 700rpm, flow speed of the mobile phase was 2mL/min, four pure components relatively were attained by isolation and purification.

结果表明：薄层层析溶剂系统为氯仿：甲醇：二乙胺=90：9：1，使荷叶中的生物碱达到了较好的分离效果，并用改良的碘化铋钾试剂喷雾显色，共分离鉴别出了5种荷叶生物碱；分析型HPLC分析检测的较优溶剂系统为甲醇：水：二乙胺=75：25：0.0125，使荷叶生物碱的各个组分达到了基线分离，并获得了较好的峰形。5、建立了高速逆流色谱和制备型HPLC技术分离纯化荷叶生物碱的具体方法。H(来源：ABC46论文网www.abclunwen.com)SCCC法在溶剂系统为氯仿：甲醇：pH4.00的水=4：3：2，色谱仪转速为700rpm，流动相流速为2mL／min的条件下，分离纯化得到了4个纯度较高的化合物。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。