分析下这个句子呢……? It is a object of this invention to modify the countercurrent extraction of mixtures comprising alkenylpyridines and alkylpyridines with aqueous acidic solutions so as to enhance the selectivity to alkenylpyridines. Additional objects and advantages of this invention will be apparent from the disclosure and the appended claims.查看更多1个回答 . 2人已关注