| 查看: 1287 | 回复: 5 | |||
| 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 | |||
anpeng木虫 (著名写手)
|
[交流]
【求助】Help: PEG Purification 已有5人参与
|
||
|
求助：聚乙二醇400的纯化方法。 下面引自Purification of Laboratory Chemicals 6th Edition PEG is available commercially as a powder or as a solution in various degrees of polymerization depending on the average molecular weight, e.g. PEG 400 and PEG 800 have average molecular weights of 400 and 800, respectively. They may be contaminated with aldehydes and peroxides. Solutions deteriorate in the presence of air due to the formation of these contaminants. Methods available for purification are as follows: Procedure A: A 40% aqueous solution of PEG 400 (2 L, average molecular weight 400) is de-aerated under vacuum and made 10mM in sodium thiosulfate. After standing for 1 hour at 25°C, the solution is passed through a column (2.5×20 cm) of mixed-bed R-208 resin which has a 5 cm layer of Dowex 50-H+ at the bottom of the column. The column was previously flushed with 30% aqueous MeOH, then thoroughly with H2O. A flow rate of 1mL/minute is maintained by adjusting the fluid head. The first 200 mL are discarded, and the effluent is then collected at an increased flow rate. The concentration of PEG solution is checked by density measurement, and it is stored (preferably anaerobically) at 15°C. 能不能用中文描述一下？ 关键是a column (2.5×20 cm) of mixed-bed R-208 resin和Dowex 50-H+是什么？ [ Last edited by anpeng on 2010-7-11 at 11:00 ] |
回复此楼» 猜你喜欢
材料与化工调剂
已经有26人回复
-
一志愿211，化学310分，本科重点双非，求调剂
已经有19人回复
-
求调剂288
已经有7人回复
-
298求调剂
已经有13人回复
-
281求调剂
已经有3人回复
-
265求调剂
已经有11人回复
-
301求调剂
已经有5人回复
-
343求调剂
已经有3人回复
-
272分材料子求调剂
已经有18人回复
-
273求调剂
已经有57人回复
wolfyloner
至尊木虫 (知名作家)
- PEPI: 2
- 应助: 755 (博后)
- 贵宾: 0.017
- 金币: 18525.1
- 红花: 107
- 帖子: 6760
- 在线: 1502小时
- 虫号: 578364
- 注册: 2008-07-04
- 性别: GG
- 专业: 应用高分子化学与物理
3楼2010-07-12 08:51:25
anpeng
木虫 (著名写手)
- 应助: 0 (幼儿园)
- 金币: 3256.2
- 红花: 4
- 帖子: 1345
- 在线: 115.8小时
- 虫号: 194582
- 注册: 2006-02-23
- 性别: GG
- 专业: 橡胶及弹性体
4楼2010-07-13 07:13:50
5楼2015-10-21 11:11:07
6楼2017-07-28 11:16:10
