醚

The isocyanate-terminated polyurethane prepolymer was also synthesized form polytetramethylene glycol and 4,4'-diphenylmethane diisocyanate in N,N-Dimethylformamide.

另外，将聚醚双醇与量之4，4'-二苯甲基二异氰酸酯行预聚合反应，形成具-NCO末端基之聚氨基甲酸酯预聚合体。

The copolycondensation type polyamic acid was synthesized by using 3,3', 4,4'-Benzophenonetetracarboxylic dianhydride as the dianhydride monomer, 4,4'-Diamino diphenylmethane and 4,4'-Oxydianiline as the diamine monomer under microwave irradiation in Dimethylformamide.

在微波辐射条件下，采用3，3'，4，4'-二苯酮四羧酸二酐、4，4'-二氨基二苯甲烷和4，4'-二氨基二苯醚为单体，N，N'-二甲基甲酰胺为溶剂，低温合成一种共缩聚聚酰亚胺的前驱体聚酰胺酸，化学亚胺化脱水环化生成BTDA型共缩聚聚酰亚胺。

The copolycondesation type polyamic acid was synthesized by using pyromellitic dianhydride and 3,3',4,4'-benzophenonetetracarboxylic dianhydride as the dianhydride monomers, 4,4'-diamino diphenylmethane and 4,4'-oxydianiline as the diamine monomers under microwave irradiation in dimethylformamide.

在N，N'-二甲基甲酰胺溶剂中，以均苯四甲酸酐和3，3'，4，4'-二苯酮羧酸二酐为二酐单体，4，4'-二氨基二苯醚和4，4'-二氨基二苯甲烷为二胺单体，采用微波辐射低温溶液共缩聚，合成了聚酰胺酸预聚体，然后亚胺化脱水、环化，生成共缩聚聚酰亚胺。

However, we measured the vapour pressures of dipropyl ether (1) and 1-propyl alcohol (2) up to about the normal boiling point of the respective pure components, which are lower than the 2-ethoxyethanol (3) boiling point.

然而我们测得二丙醚(1)和1－丙醇(2)的蒸汽压分别达到了各自正常情况下的沸点，这比2-乙氧基乙醇(3)的沸点要低的多。

So, to avoid excessive extrapolations of the Antoine equation for the two more volatile components (dipropyl ether and1-propyl alcohol), we have decided to use in this work other equations to estimate these vapour pressures which are applicable in a larger temperature range.

因此，为了避免安托万方程对这两种挥发性更强的成分(二丙醚和1－丙醇)的过度计算，我们决定在本工作中用其他的适用于更大温度区间的方程来估计它们的蒸汽压。

The activity coefficients presented in Tables 4 and 5 indicate that the dipropyl ether (1)+ 2-ethoxyethanol (3) system shows positive deviations from ideal behaviour and that the 1-propyl alcohol (2)+ 2-ethoxyethanol (3) system exhibits no deviation from ideal behaviour and no additional azeotropes are present.

表4和表5所示的活度系数表明，&二丙醚+2-乙氧基乙醇&体系与理想模型表现出正偏差而&1-丙醇+2-乙氧基乙醇&体系则无偏差，并且不存在其他共沸物。

In order to carry out the separation of the azeotropic mixture dipropyl ether + 1-propyl alcohol by extractive distillation, we are studied the influence on the phase equilibria behavior four different solvent: 1-pentanol [2], butyl propionate [3], N,Ndimethylformamide [4] and 2-ethoxyethanol.

为了用萃取性蒸馏法分离二丙醚和1－丙醇组成的共沸混合物，我们正在研究4种不同溶剂对相平衡行为的影响：1-戊醇[2]、丙酸丁酯[3]、N，N－二甲基甲酰胺[4]和2-乙氧基乙醇。

A method is introduced for quantitative determination of cinmethylin by gas chromatography on 5 % ov - 101 packed column and flame - ionigation detector using dipropyl phthalate as internal standard The method was simple, rapid, accurate and practical.

采用气相色谱法， 5％ OV— 101填充柱和氢火焰离子化检测器，以邻苯二甲酸二丙酯为内标，对环庚草醚进行定量测定。

As can be seen in Fig. 5, dipropyl ether will be recovered in the distillate using 1-pentanol, N,N-dimethylformamide and 2-ethoxyethanol as entrainers and butyl propionate is the only entrainer studied that inverts the volatility of the azeotropic mixture.

从图 5可以看出，使用1-戊醇、N，N-二甲基甲酰胺和2-乙氧基乙醇作为共溶剂时二丙醚将在馏分中回收，丙酸丁酯是唯一与共沸混合物挥发性相反的共溶剂。

Dipropyl ether will be recovered in the distillate using 1-pentanol.

使用1-戊醇。N.N-二甲基甲酰胺和2-乙氧基乙醇作为共溶剂时二丙醚将在馏分中回收。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。