Controlled Release of Volatile Aldehydes and Ketones from Dynamic Mixtures Generated by Reversible Hydrazone Formation
作者:Barbara Levrand、Wolfgang Fieber、Jean-Marie Lehn、Andreas Herrmann
DOI:10.1002/hlca.200790237
日期:2007.12
Delivery systems generated by reversible hydrazone formation from hydrazine derivatives (see Fig. 1) and carbonyl compounds in H2O efficiently increase the long-lastingness of volatile aldehydes and ketones (R1R2CO) in various perfumery applications. The hydrazones are usually obtained in an (E) configuration at the imine double bond (NHNC) and, in the case of aliphatic acylhydrazones R′CONHNCR1R2
在H 2 O中由肼衍生物(见图1)和羰基化合物可逆形成而生成的传递系统有效地提高了各种香料应用中挥发性醛和酮(R 1 R 2 CO)的持久性。通常以(E)构型在亚胺双键(NHNC)上获得,对于脂族酰基hydr R'CONHNCR 1 R 2(R'=烷基),相对于酰胺而言,其为顺式和反式构象异构体键(CONHN)。平均自由能垒约为。通过可变温度的1 H-NMR测量确定了78 kJ / mol的酰胺键旋转(图2)。在H 2 O存在下,的形成是完全可逆的,达到了由肼衍生物,羰基化合物和相应的composed组成的平衡。通过UV / VIS光谱进行的动力学测量表明,that的形成和水解达到了相同的平衡。速率常数强烈依赖于pH值,并且随着pH值的降低而增加(表1)。肼结构对速率常数的影响不如pH效应那么明显,表面活性剂的存在降低了平衡速率(表1和表2)。3)。formation形成的完全可逆性允许通