The reaction conditions on oxidation of 2 - methylpyridine to 2 - acid by oxidation of potassium dichromate were studied. 研究了以2-甲基吡啶为原料,以重铬酸钾为氧化剂,利用化学氧化法合成 2- 吡啶甲酸的反应条件.
A number of staircases ascend from the cobbled streets onto the ramparts.一段石阶从鹅卵石路上一直向上直通城墙。Then we ascend steeply through forests of rhododendron.然后我们在杜鹃花丛中沿着陡坡向上爬。The path started to ascend more steeply.小径开始陡峭而上。...