本次试验通过对液体石蜡减压蒸馏取不同温度段的三个馏分，获得了三种包含不同碳链长度烷烃的馏分1、2、3。
During the first step , it is requested to prepare three kinds of alkanes which are different in the length of the hydrocarbon chains . The suited alkanes which are numbered 1 # , 2 # , 3 # are acquired by the vacuum distillations of paraffin .
烷烃馏分