Structure-selectivity relationship in the chemoselective hydrogenation of unsaturated nitriles
作者:P KUKULA、K KOPRIVOVA
DOI:10.1016/j.jcat.2005.06.011
日期:2005.8.15
(cyclohex-1-enyl-acetonitrile, double bond at C-6 in geranylnitrile). In conjugated systems, such as acrylonitrile or 2-pentenylnitrile, the activated double bond is hydrogenated before the nitrile. An additional methyl substituent at the double bond enhances the selectivity for unsaturated amines and, thus, 3,3-dimethyl-acrylonitrile and geranylnitrile were hydrogenated with selectivity up to 40%. The highest selectivities
在Cr掺杂后将带有双键不同取代基的几种结构不同的不饱和腈(肉桂腈,环己-1-烯基乙腈,丙烯腈,3,3-二甲基丙烯腈,香叶腈,2-戊烯腈和2-戊烯腈)氢化。雷尼钴和镍及其未掺杂的等价物。相对于腈基的双键取代和位置对于确定不饱和胺的化学选择性至关重要。当双键在空间上受阻或离腈基太远时(环己-1-烯基乙腈,香叶基腈中C-6处的双键),该双键不会被氢化。在诸如丙烯腈或2-戊烯腈的共轭体系中,活化的双键在腈之前被氢化。双键上的另一个甲基取代基提高了对不饱和胺的选择性,因此,将3,3-二甲基丙烯腈和香叶基腈以高达40%的选择性氢化。在非共轭体系(如环己-1-烯基乙腈和3-戊烯腈)的氢化过程中,对不饱和胺的选择性最高(高达90%)。