| 查看: 107 | 回复: 3 | |||
| 当前主题已经存档。 | |||
| 【悬赏金币】回答本帖问题，作者liuxuanyan将赠送您 3 个金币 | |||
| 当前只显示满足指定条件的回帖，点击这里查看本话题的所有回帖 | |||
liuxuanyan金虫 (小有名气)
|
[求助]
怎么除去环己烷中的芳烃
|
||
|
做紫外时需要环己烷作溶剂，我们实验室只有分析纯的，通过紫外扫描发现在250nm左右有吸收，请问在怎么除去环己烷中的芳烃，消除此段吸收？ 我用硫酸洗过后，吸收有减弱，但是再经过蒸馏，无水硫酸钠干燥后，在300-260nm间出现了强吸收，请问这是为什么？？ |
回复此楼» 猜你喜欢
一志愿武理085500机械专业总分300求调剂
已经有6人回复
-
材料学求调剂
已经有5人回复
-
考研调剂
已经有4人回复
-
281求调剂
已经有4人回复
-
0805 316求调剂
已经有6人回复
-
085601求调剂总分293英一数二
已经有3人回复
-
08工学调剂
已经有17人回复
-
340求调剂
已经有4人回复
-
311求调剂
已经有3人回复
-
食品专硕 一志愿双一流 328
已经有4人回复
★
liuxuanyan(金币+1):谢谢你，我去试试！
liuxuanyan(金币+1):谢谢你，我去试试！
|
Cyclohexane [110-82-71 M 84.2, f 6.6O, b 80.7O, d24 0.77410, n 1.42623, n25 1.42354. Commonly, washed with conc H2SO4 until the washings are colourless, followed by water, aq Na2C03 or 5% NaOH, and again water until neutral. It is next dried with P2O5, Linde type 4A molecular sieves, CaC12, or MgS04 then Na and distd. Cyclohexane has been refluxed with, and distd from Na, CaH2, LiAl& (which also removes peroxides), sodiudpotassium alloy, or P2O5. Traces of *benzene can be removed by passage through a column of silica gel that has been freshly heated: this gives material suitable for ultraviolet and infrared spectroscopy. If there is much *benzene in the cyclohexane, most of it can be removed by a preliminary treatment with nitrating acid (a cold mixture of 3OmL conc HNO3 and 70mL of conc H2SO4) which converts *benzene into nitrobenzene. The impure cyclohexane and the nitrating acid are placed in an ice bath and stirred vigorously for 15min, after which the mixture is allowed to warm to 25O during lh. The cyclohexane is decanted, washed several times with 25% NaOH, then water dried with CaC12, and distd from sodium. Carbonyl-containing impurities can be removed as described for chloroform. Other purification procedures include passage through columns of activated alumina and repeated crystn by partial freezing. Small quantities may be purified by chromatography on a Dowex 710-Chromosorb W gas-liquid chromatographic column. Rapid purification: Distil, discarding the forerun. Stand distillate over Grade I alumina (5% w/v) or 4A molecular sieves. [ Last edited by jianmei97 on 2007-6-13 at 12:24 ] |
4楼2007-06-13 12:23:34
abcdelm
木虫 (著名写手)
月落之后，不说爱你*abcdelm
- 应助: 4 (幼儿园)
- 贵宾: 0.235
- 金币: 2249.5
- 散金: 6
- 红花: 4
- 帖子: 2226
- 在线: 142.7小时
- 虫号: 374398
- 注册: 2007-05-17
- 专业: 合成药物化学
2楼2007-06-07 20:18:32
liuxuanyan
金虫 (小有名气)
- 应助: 0 (幼儿园)
- 金币: 924.7
- 散金: 129
- 红花: 1
- 帖子: 87
- 在线: 26小时
- 虫号: 311552
- 注册: 2006-12-30
- 性别: MM
- 专业: 有机合成
3楼2007-06-08 22:47:29
