| Pages:
1
..
8
9
10 |
jon
Hazard to Others
Posts: 225
Registered: 11-1-2006
Member Is Offline
|
|
cyanide became safe to handle??
did i just read that????
or am i on drugs?
|
|
|
Sedit
International Hazard
Posts: 1022
Registered: 23-11-2008
Member Is Offline
Mood: Wishing death on all those that stand in ones way of greatness
|
|
Well you sort of read that but yes you are on drugs...
Peach was arguing the semantics on the usage of calling a compound to toxic(accumulates in the body such as Hg) and harmful(death on the spot like H2S
or HCN)
Knowledge is useless to useless people.
Feed you brain: http://www.thevespiary.org/sedit/
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~ Maynard James Keenan
|
|
|
watson.fawkes
International Hazard
Posts: 1033
Registered: 16-8-2008
Member Is Offline
|
|
You are illustrating why changing ordinary language usage into jargon is completely
dangerous in this case. The reason for labeling compounds toxic and harmful is that these words are meaningful in an ordinary sense to ordinary
people. If you use these meanings in some jargon-laden way, it not only fails to communicate, but communicates something that is other than truthful.
|
|
|
peach
National Hazard
Posts: 449
Registered: 14-11-2008
Location: Blighty
Member Is Offline
Mood: curious kitty beta turbo edition
|
|
They're now planning to use H2S for a form of suspended animation of seriously injured casualties on the way to surgery. They worked out that a very
precise dose of H2S antagonizes (blocks) the sites that would be damaged by oxidation when normal homeostasis wasn't functioning. They've been testing
it on mice and the results are so positive they're going to human trials. I think they'll be injecting it dissolved in solution. The 'victim' also
needs cooling in an ice bath. 
I don't want to start arguing, but it's somewhat ironic you're calling it jargon when you'd likely have a fit on me if I started using none
standardized names for reagents and solvents. I know what you're saying, but I think jon is joking.
He's actually illustrating my own point perfectly well. In that people now assume harmful means safe to handle. Whilst genuine lab suppliers are still
shipping things that should now be labeled toxic as harmful. It may as well not exist as a label.
And I know none of this has anything to do with aldehydes and I hope I haven't annoyed you. I didn't mean to do so if I did, I just don't like the
blanket use of the word toxic, as it desensitizes people to the real risks. I'll shut up now.
[Edited on 28-6-2010 by peach]
|
|
|
Reference
Anders Hoveland
Posts: 13
Registered: 12-7-2010
Member Is Offline
|
|
Just a thought, if you can get your hands on a Selenium compound,
acetone reacts with selenium dioxide to make an aldehyde.
O=CH-CO-CH3
http://www.transtutors.com/chemistry-homework-help/aldehydes/oxidat...
You could protect the aldehyde by condensing with NH4OH, leaving the ketone vulnerable to be reduced (for example with hydrogen iodide) but then I am
unsure of how to recover the aldehyde again, after it has condensed. Maybe reacting with NaOH will give off ammonia gas and make NaOCH(OH)-CH2-CH3 ,
then acidify to recover the aldehyde.
|
|
|
Melgar
Hazard to Others
Posts: 140
Registered: 23-2-2010
Member Is Offline
|
|
Treating amino acids with bleach does indeed produce aldehydes, for example, alanine + bleach gives acetaldehyde. However, this reaction also
produces CO2 and NH3, and the NH3 is chlorinated into one of the chloramines. Still not entirely sure how to get rid of those...
|
|
|
Jimmymajesty
Hazard to Self
Posts: 78
Registered: 9-7-2009
Member Is Offline
|
|
I never succeeded in recovering the acetaldehyde from dilute solutions, I usually got an unpleasant smell, that is far away from the smell of pure
acetaldehyde. Also the acetaldehyde does not like to be acidified/basified you
will get either a yellow solution with and acrid smell or an orange sticky polymer with an apple like smell, depending on the pH that you disturb poor
little CH3CHO molecule
|
|
|
rrkss
Hazard to Others
Posts: 167
Registered: 18-12-2009
Member Is Offline
|
|
Quote: Originally posted by Hoveland  | What is the reaction with acetaldehyde when the pH goes to high or too low?
I found an excellent explanation about aldehydes: http://www2.chemistry.msu.edu/faculty/reusch/VirtTxtJml/aldket1.htm
which did not seem to tell what these reactions might be, but as a side note, I did learn
"Although the addition of water to an alkene is exothermic and gives a stable product (an alcohol), the uncatalyzed reaction is extremely slow due to
a high activation energy . The reverse reaction (dehydration of an alcohol) is even slower, and because of the kinetic barrier, both reactions are
practical only in the presence of a strong acid." |
Look up aldol condensation for part 1. Part 2 of your response has nothing do do with aldehydes or acetadlehyde.
|
|
|
| Pages:
1
..
8
9
10 |
![[*]](images/xpblue/default_icon.gif){kind=icon}
