查询词典 alcoholate

The results showed that the addition of alcoholate increased the elution recovery of phenolic acids on resins in supercritical CO2. The infrared spectroscopy was used to study the interaction between solute and solvent molecules in supercritical fluid. The hydrogen bond between alcoholate entrainer and phenolic acid was the main factor to increase the ability of supercritical elution. The results appeared that salvianolic acids could be extracted by supercritical carbon dioxide with ethanol as entrainer.

结果表明：醇类夹带剂的加入能大大提高树脂上酚酸类化合物的超临界洗脱率；通过红外光谱技术研究了超临界流体中分子间的相互作用与超临界洗脱过程的关系，认为醇类夹带剂与酚酸类化合物的氢键作用是提高酚酸类化合物洗脱率的主要因素；以乙醇为夹带剂的超临界CO2洗脱可应用于丹参酚酸的提取。

Because the olefinic hydroxyl groups are linked with olefinic carbon, so it can ionize H〓 ion and present the properties of weak acid, and so the olefinic hydroxyl groups change into the structure of alcoholate in the presence of alkali , but the structure of alcoholate may change into the structure of olefine alcohol again, after the Na〓 ions is removed, or when the pH value of its solution turn into pH. Because the structure of the olefine alcohol is not stable and is easy to isomerizate to become the structure of olefine ketone, so there appear the ca. 1730cm〓 C=O absorption peak in the IR spectra of the products.

明确指出了在C〓、C〓富勒醇中存在烯碳羟基与叔碳羟基等二类羟基，烯碳羟基由于与一个共轭体系相连，从而其羟基可以离解而呈现出弱酸的性质，因而在碱性条件下易形成烯醇钠盐的结构，当除去钠离子后或在酸性溶液中，烯醇钠盐结构转变为烯醇结构，但由于烯醇结构不如烯酮结构稳定，从而形成烯醇结构后，烯醇结构异构化为烯酮结构，因此在其产物的IR谱图上出现1730cm〓附近的C=0吸收信号。

For example, using chiral tungsten 2'-pyridinyl alcoholate complex at 50 ℃, the ee value was increased from 54% to 78%.

在磷霉素的不对称合成研究方面只有Giordano等[4]是以顺丙烯膦酸为起始原料进行的。

The coating is effected by impregnation with aluminium isopropoxide in benzene solution and the alcoholate is then hydrolysed in situ, and the whole is heated to 600℃ for activation.

涂溃方法系将耐火砖用异丙醇铝的苯溶液浸渍，再把浸上去的异丙醇铝水解，并在600℃下活化。

When chiral molybdenum 2'-pyridinyl alcoholate complexe was used as catalyst, the enantiomeric excess was 79. 5% at 0℃ in CH〓Cl〓.

我们目前经实验优化取得的最佳反应条件是：使用MoO〓〓作催化剂，在CH〓Cl〓中于0℃反应，所得产物的ee值达到了79.5％。

A further advantage of this method of working is that the sodium alcoholate can very conveniently be made by mixing the sodium with a proportion of the hydrocarbon which is to be used as the solvent for the reaction and adding the required amount of the alcohol thereto.

另外这种方法还有一个优点：纳和一定比例的碳氢化合物混合在加入所需数量的乙醇可以方便制备乙醇纳，而碳氢化合物可以作为溶剂使用。

In this paper, chiral molybdenum or tungsten 2'-pyridinyl alcoholate complex catalyzed asymmetric epoxidation of cis-1-propenylphosphonic acid in H2O was reported.

目前磷霉素的生产是通过以Na2WO4为催化剂、在乙醇中以30%的H2O2将顺丙烯膦酸环氧化得到消旋产物，再利用α-苯乙胺进行拆分而得到[2，3]。

The produced compound pipe materials are widely used in conveying hot water, pure water, sea water, oil, phenol, alcoholate and other un-oxidizing organic liquids.

生产的复合管材广泛用于输送热水、纯净水、海水、油类、酚、醇非氧化性有机流体等。

The highest ee value of 71% was achieved by using chiral molybdenum 2'-pyridingyl alcoholate complex at 0 ℃. After addition of phase transfer catalyst Bu4NBr, the yield and ee value were remarkably increased.

其中手性吡啶醇二氧合钼在0℃下的对映选择性ee值达到71%；加入相转移催化剂四正丁基溴化铵，催化剂的活性和对映选择性有显著提高，其中手性吡啶醇二氧合钨在50℃下ee值由54％提高到78%。

The catalyst includes: supported Ziegler-Natta catalyst of titanium halide compound and organic electron donor compound supported with MgCl2 alcoholate carrier; aluminoxane prepared with trialkyl aluminum and water; and one kind of organic electron donor, such as organosilicon compound R2Si(OCH3)2, where R is phenyl, isopropyl, isobutyl or cyclopentyl.

该催化剂包括，a一种负载型的Ziegler-Natta催化剂，即将卤钛化合物和有机给电子体化合物负载在氯化镁醇合物载体上得到的固体催化剂，b一种通过三烷基铝与水反应而制备得到的铝氧烷和c一种有机电子给体，如有机硅化合物R 2 Si(OCH 3 ) 2 ，其中R为苯基、异丙基、异丁基或环戊基。

Green function defined inphase space differs from one in coordinate space by its struc-ture which exhibits nonlocatity in coordinates and oscillatorybehavior with respect to momenta.

在相空间中定义的Green函数不同于通常坐标空间的Green函数，在结构上显示出对坐标的高度非局域性，而对动量则显示出振荡行为。

The upper front part of a saddle;a saddlebow.

前鞍桥马鞍前面的上部分；前鞍桥