氯碘化物

And to make the product be easy of purification, the excess of amine was reduced to 50% from 150%. Then the diiodoalkane reacted with dialkylmethylamine into diquaternary ammonium iodide, and obtained three diquaternary compounds whose spacer groups were -(CH2)6-, N,N"-dimethyl- N,N,N",N"-tetraoctyl-1,6-hexane diammonium diiodide, N,N"-dimethyl-N,N,N",N"-tetradecyl-1,6-hexane diammonium diiodide, N,N"-dimethyl-N,N,N",N-tetradodecyl -1,6-hexane diammonium diiodide.

对于更长间隔链的双子型季铵盐，一方面为了加快亲核取代反应速率，先将1，6-二氯己烷、3-氧杂-1，5-二氯戊烷转化成1，6-二碘己烷、3-氧杂-1，5-二碘戊烷，另一方面为了降低产物提纯的难度，将叔胺的过量由150%降到50%，使二碘代烷与双长烷基甲基叔胺在相同的温度下、反应相同的时间，经过相同的后处理，得到3个间隔链为-(CH2)6-的双子型季铵碘化物，(C8H17)2N+(CH3)(CH2)6 (CH3)N+(C8H17)2·2I-、(C10H21)2N+(CH3)(CH2)6(CH3)N+(C10H21)2·2I-和(C12H25)2N+(CH3)(CH2)6(CH3)N+(C12H25)2·2I-。

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。