教授最近丟給了我一篇 paper 要我合成新的 ligand 但是做了幾次都不是很順利 還有一些後面的步驟也不甚了解 再加上我們實驗室是做無幾的 沒有學長會合成 所以只得上來請教大家 目前我想要合成的產物是 2,3-二甲基-2,3-二羥胺基丁烷 (2,3-Dimethyl-2,3-hydroxylaminebutane) 起始物是 2,3-二甲基-2,3-二硝基丁烷 (2,3-Dimethyl-2,3-dinitrobutane) 也就是要把硝基(R-NO2)轉變成羥胺基(R-NHOH) 以下是 paper 內容 -- 2,3-Dimethyl-2,3-dinitrobutane (17.6 g, 0.1 mol) was dissolved in a mixture of THF (300 mL) and water (50 mL). Zn powder (27 g) was added all at once to this solution cooled to 8–10 °C in an ice bath. A solution of NH4Cl (43 g, 08 mol) in H2O (150 mL) was added dropwise to this slurry within 2 h, with continued stirring for 1 h at 10 °C, and the flask was stored in a fridge (4–6 °C) for 16 h. The slurry was filtered, and the precipitate was carefully washed with THF (4 X 100 mL). The precipitate was then dried by three washings with diethyl ether and carefully collected (59 g). The solution was evaporated under vacuum until THF ceased to distill off. Then the solution was protected from air, and sodium carbonate (50 g) and sodium chloride (30 g) were added with cooling. Continuous extraction with chloroform (400 mL) was performed over 18 h. A white powder was obtained (9.4 g, 63% yield), mp 182 °C. -- 而在操作的過程中出現了幾個問題 第一個是 我的起始物點在 TLC 片上顏色很淡 我不太知道要怎麼去追蹤說它反應完了沒有 第二個是 文中有提到 The precipitate was then dried by three washings with diethyl ether and care- fully collected (59 g). 我想問的是 過濾出來的東西不就是鋅粉和一些沈澱嗎 為什麼還需要過搜集秤重呢 一般不是洗完濾餅後直接扔掉嗎？ 第三個是 The solution was evaporated under vacuum until THF ceased to distill off. Then the solution was protected from air, and sodium carbonate (50 g) and sodium chloride (30 g) were added with cooling. 可是他不是有說要把 THF 收乾嘛 這樣哪來的 solution 啊 還是這個 solution 指的是一開始加入的 50ml water 呢 又他提到的 Then the solution was protected from air 指的是要在無水無氧的環境下通氮氣操作嗎？ 還有最後的 extraction with chloroform (400 mL) was performed over 18 h 這邊說的應該是索氏萃取(Soxhlet extraction) 而不是真的要我拿分液漏斗去搖 18 hr 吧... 但是索氏萃取不是都是固體在用的嗎 還是加入 sodium carbonate 跟 sodium chloride 目的就是要讓產物吸附上去做索氏萃取呢 問題有一點多 拜託大了家 感激不盡！ -- 全部舊記憶 這刻重遊 http://www.wretch.cc/blog/montent By:墨水藍 --

※ 發信站: 批踢踢實業坊(ptt.cc), 來自: 1.175.193.106 ※ 文章網址: http://webptt.com/m.aspx?n=bbs/Chemistry/M.1403678540.A.1A3.html ※ 編輯: Alcor (1.175.193.106), 06/25/2014 14:44:07