酯交换反应中由于反应物dmo的大量存在阻碍了平衡常数较小的歧化反应的进行,使得dpo选择性和收率较低。
A mass of DMO in the transesterification course inhibited the disproportionation which has a small equilibrium constant. As a result, selectivity and yield of DPO were low.
本文分别用双共振选择性自旋去耦、双共振自旋搔动方法判定异植物醇中ABX体系耦合常数的相对符号为同号。
The relative signs of coupling constants in ABX system for isophytol were determined using two methods of double resonance: selective spin decoupling and spin tickling methods.
一定条件下该硝化剂具有较好的反应位置选择性,这一是由于反应介质低的介电常数,二是多孔载体也具有明显的作用。
In this system good regioselectivity can be achieved mainly because of the existence of a porous support and the low dielectric constant of the reaction media.
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