查询词典 catalyst

With methanol as solvent and NaOH as catalyst,the influence of the concentration of NaOH ,reaction temperature and reaction time to the alcoholysis of polyvinyl acetate is studied by the homogeneous design procedure.

使用均匀设计法研究了甲醇作为溶剂，氢氧化钠作为催化剂时，聚醋酸乙烯酯醇解反应中碱的物质的量比、反应温度和反应时间对聚乙烯醇醇解度的影响。

The catalysts used in the preparation of di acetone alcohol by the Aldol condensation were studied in detail, and a new kind of catalyst Ca 2/Al 2O 3 is developed.

对丙酮经Aldol缩合制二丙酮醇的催化剂进行了研究，研制出新型催化剂Ca 2 /Al2 O3，这种催化剂对丙酮的缩合反应具有较理想的活性及选择性。

We first examined the ability of the catalyst to promote the direct aldol reaction between acetone and 4-nitrobenzaldehyde under various conditions.

通过偶联反应将催化剂1固载到硅胶上，并将其用于催化环己酮和硝基苯甲醛的aldol反应，dr值最高达到90：10，ee最高76%。

In part Ⅰ, the aquous direct aldol reactions catalyzed by small organo-catalyst—imidazolc were studied in detailed.

本文第一部分详细研究了咪唑为有机小分了催化剂催化水相直接羟醛缩合反应。

When 5 mol% of 1a was used to catalyze the reaction at 0℃to room temperature, the aldol products were obtained with up to 96% ee, which were comparable to the effect with 30 mol% of L-proline as catalyst.

在0℃～室温下，以5mol％的1a催化即可获得相当或优于30mol％脯氨酸本身所具有的催化效果，ee值最高可达96％。

Through experiment, we have found that the combination of naphthol/sodium naphtholate is a high efficient bifunctional catalyst for direct aldol reaction.

通过实验，我们发现并筛选出了一组活性较高的β-萘酚和其钠盐双功能催化剂，该方法不需要预先活化Aldol反应的底物就能直接反应，且反应可在室温进行，条件温和，速度快，收率高达98%。

The catalyst Ti-MCM-41 is used in epoxidation of propylene, in which cumenen hydroperoxide is used as oxidant, alkalescence of solution, reaction temperature and solvent are tested.

将所合成的Ti-MCM-41催化剂用于CHP氧化丙烯的环氧化反应中，对反应液的酸碱性、反应温度及溶剂进行了考察。

In addition, comparing to the alkali metal catalyst, the Ce overlayer is difficult to be removed even heating to 700K.

此外，和碱金属/半导体的情况有所不同，700K的退火也不能有效地除去半导体界面的稀土金属覆盖层。

The findings of present work show that organic/water ratio,alkali metal alkali, phase transfer catalyst, reaction time, reaction temperature, all of them have influence to the molecular weight and yield of the production.

详细研究了溶剂/水的配比、碱金属碱、相转移催化剂、反应温度、反应时间等因素对产品分子量和产率的影响。

These reactions are usually the catalyst in acid or alkali under ...

这些反应通常在酸或碱的催化作用下进行。。。。

There are different types of personal loans available.

有许多不同类型的个人贷款优惠。

The above mentioned teaching model of spiral rising can be used to avoid rigidness in teaching.

上述螺旋式上升的教学模式，可以避免教学形成模式後的僵化现象。