chemrox
International Hazard
Posts: 2961
Registered: 18-1-2007
Location: UTM
Member Is Offline
Mood: LaGrangian
|
|
returning to labwork issues
As I've told some of you, I ws out of wet chemistry for a long time. In school and after at my jobs I had a reputation of being very good in the lab.
It seemed you just followed the written procedures and everything worked just fine. Then when you needed something new you varied the procedure in a
way that seemed appropriate based on experience, reading and intuition.
After decades away from it I've been expecting to get the results indicated in the published methods without any hassles.
It hasn't been that way. Things ofetn don't work the first time and sometimes not after three or four attempts. I'm not talking about super tricky
high tech experiments. I haven't been trying to use high temperatures or ultra low vacuums. I remember seeing guys in lab at school who would make
their reflux apparatus into a fountain while the rest of us made nylon or some damn thing. I always wondered how anyone could fuck up soemthing so
simple as just following directions and now here I am.
Damnit! Maybe I should do a bunch of simple preps before I waste too much more material and money. I hope it comes back. I ws thinking since I need
ether and its gotten so expensive, I'd make it in the lab. Also I've used some chlorinated solvents I then flashed off mixed together. I can
fraction these and recover some of them. This all seems a little tedious but I think I need the practice. I'd like to get to where I can rely on
procedures again.
[Edited on 26-9-2007 by chemrox]
|
|
|
chromium
Hazard to Others
Posts: 284
Registered: 27-6-2005
Member Is Offline
Mood: reactive
|
|
| Quote: | Originally posted by chemrox
Maybe I should do a bunch of simple preps before I waste too much more material and money.
[Edited on 26-9-2007 by chemrox] |
This is what i always do when i have been for some months away from my lab. I destill some water, prepare some ethyl acetate or benzoic acid (from
toluene), then something simple to the direction where i plan to go.
I made this as rule for me after some minor accidents ( like breaking glass, burning fingers or messing everything up with sulfuric acid ) almost
always happened if i started with something not so simple after long pause.
[Edited on 27-9-2007 by chromium]
When all think alike, then no one is thinking. - Walter Lippmann
|
|
|
Magpie
lab constructor
Posts: 5939
Registered: 1-11-2003
Location: USA
Member Is Offline
Mood: Chemistry: the subtle science.
|
|
chemrox I sympathize with you.
Usually if I carefully follow a published procedure I get the product at or near the reported yield. But every once in a while it just doesn't work -
even if I try it several times. This is very discouraging and makes one doubt his competence as a chemist.
This is occuring with me right now. I have a procedure for making KOCN from Inorganic Syntheses. This is an old and respected publication,
and the procedure has been peer proven by two chemists. So why in the hell won't it work for me?
Like you I tend to revert to simpler procedures involving the same chemicals so that I get a feel for them and develop some confidence that my
techniques are OK.
[Edited on by Magpie]
The single most important condition for a successful synthesis is good mixing - Nicodem
|
|
|
chemrox
International Hazard
Posts: 2961
Registered: 18-1-2007
Location: UTM
Member Is Offline
Mood: LaGrangian
|
|
Thanks a lot .. both of you! At least I don't feel so alone. "incompetent" about the worst thing I can say about someone .. and how I feel
sometimes.
[Edited on 27-9-2007 by chemrox]
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
