| Pages:
1
..
5
6
7
8
9
..
30 |
Formula409
Hazard to Others
Posts: 129
Registered: 13-12-2008
Member Is Offline
Mood: No Mood
|
|
Imines form water-soluble hydrochlorides, don't they?
Formula409.
Edit: Yes they can : http://www.journalarchive.jst.go.jp/english/jnlabstract_en.p...
[Edited on 20-6-2009 by Formula409]
|
|
|
Sedit
International Hazard
Posts: 1939
Registered: 23-11-2008
Member Is Offline
Mood: Manic Expressive
|
|
Organic Hypochlorites like EtOCl are effective chlorinating agents for the conversion of toluene to Benzyl Chloride.
They are synthesised in a cold dim enviroment to prevent explosion risk from R-OH + NaOH + Cl2 = R-OCl + NaCl + H2O
My question is could this possibly be used insitu to chlorinate Toluene or is purification a must? My logic is the faster it is used for chlorination
and turned back into EtOH the less one risk the explosion from it. The main problem I see here is the water formed interfering with the conversion of
BnCl by Hydrolysis to HCl + BnOH. Drying with MgSO4 I guess would be possible but would also take a large amount of drying agent I would think.
Even if BnOH was the main product this still would not pose a problem since BnO is the final target compound to begin with. I know of all the other
ways to get there so lets not make it a discussion on that please. Just curious about this reaction in general.
Knowledge is useless to useless people...
"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
|
|
|
UnintentionalChaos
International Hazard
Posts: 1454
Registered: 9-12-2006
Location: Mars
Member Is Offline
Mood: Nucleophilic
|
|
Quote: Originally posted by Sedit  | Organic Hypochlorites like EtOCl are effective chlorinating agents for the conversion of toluene to Benzyl Chloride.
They are synthesised in a cold dim enviroment to prevent explosion risk from R-OH + NaOH + Cl2 = R-OCl + NaCl + H2O
My question is could this possibly be used insitu to chlorinate Toluene or is purification a must? My logic is the faster it is used for chlorination
and turned back into EtOH the less one risk the explosion from it. The main problem I see here is the water formed interfering with the conversion of
BnCl by Hydrolysis to HCl + BnOH. Drying with MgSO4 I guess would be possible but would also take a large amount of drying agent I would think.
Even if BnOH was the main product this still would not pose a problem since BnO is the final target compound to begin with. I know of all the other
ways to get there so lets not make it a discussion on that please. Just curious about this reaction in general. |
consider perhaps tert-butyl hypochlorite which is more stable and somewhat less suicidal to work with.
do you have a reference for the conversion of toluene to benzyl chloride?
Department of Redundancy Department - Now with paperwork!
'In organic synthesis, we call decomposition products "crap", however this is not a IUPAC approved nomenclature.' -Nicodem
|
|
|
Sedit
International Hazard
Posts: 1939
Registered: 23-11-2008
Member Is Offline
Mood: Manic Expressive
|
|
Yes, It was posted by SC Wack some time back in the organic hypochlorite threed. Its the first post on the second page.
http://www.sciencemadness.org/talk/viewthread.php?tid=1896&a...
Link to the file: http://www.sciencemadness.org/talk/files.php?pid=47308&a...
Suicidal don't even appear to be the word for these compounds and its mostly just for academia at the moment.
Im curious of BnCl or more then likely BnOH could be formed directly after the EtOCl or which ever organic hypochlorite thats used does. Excess NaOH
could be used to neutralize the formed HCl I would think and more then lead to Benzyl Alcohol. But since BnOH in concentrated acid is suppose to give
BnCl also im a little lost as to the product of performing this in one pot if its at all possible.
[Edited on 22-6-2009 by Sedit]
Knowledge is useless to useless people...
"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
|
|
|
The_Davster
A pnictogen
Posts: 2861
Registered: 18-11-2003
Member Is Offline
Mood: .
|
|
I looked for a hypochlorite chlorination of toluene (only google) and my cursory results only turned up ring chlorination (attachment)
EDIT: Ah, excellent I knew I had seen the sidechain chlorination reaction somewhere before.
However ethyl hypochlorite is not too bad, at least Axt and myself have made it without incident. Smells horrible though, perhaps tBu would stink
less with its lower vapour pressure. Of course, tBu also offsets the explosion risk 
Attachment: ref1 chloro.pdf (599kB)
This file has been downloaded 726 times
[Edited on 22-6-09 by The_Davster]
|
|
|
Sedit
International Hazard
Posts: 1939
Registered: 23-11-2008
Member Is Offline
Mood: Manic Expressive
|
|
Quote from the paper
| Quote: | Results and Discussion
Reaction with Toluene.
-Toluene was chosen as
an initial substrate for our study since the occurrence
of side chain or ring substitution of halogen
is in general diagnostic for radical or polar processes.
Preliminary experiments at 40' using excew
(3: 1) toluene and azobisisobutyronitrile (AIBN)
or light as initiator showed a rapid reaction after a
variable induction period, complete consumption
of hypochlorite, and the formation of benzyl chloride
and t-butyl alcohol as major products. A more
detailed study of the effect of reaction variables on
rate gave the results appearing in Table I, while |
Knowledge is useless to useless people...
"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
|
|
|
sparkgap
International Hazard
Posts: 1234
Registered: 16-1-2005
Location: not where you think
Member Is Offline
Mood: chaotropic
|
|
I may just not be looking hard enough, but are there any sites like SDBS that have two-dimensional spectra (e.g. COSY, NOESY, HSQC, HMBC)?
sparky (~_~)
"What's UTFSE? I keep hearing about it, but I can't be arsed to search for the answer..."
|
|
|
jokull
National Hazard
Posts: 506
Registered: 22-2-2006
Location: Everywhere
Member Is Offline
Mood: Ice glassed
|
|
Dear sparky,
I don't know such a kind of database, but I do know there is a 2D NMR predictor from ACDLabs, it also have the capability of being tuned to improve
the predictions.
I don't rememeber if this module is included within the acdlabs 11 suite posted somewhere in the forum, but I hope so.
Your question pulled out my curiosity...I found this site:
http://www.ebi.ac.uk/nmrshiftdb/
maybe it would be helpful.
[Edited on 22-6-2009 by jokull]
|
|
|
Sedit
International Hazard
Posts: 1939
Registered: 23-11-2008
Member Is Offline
Mood: Manic Expressive
|
|
Can an enamine reduction using formic acid take place in a highly acidic enviroment of 60% H2SO4?
I see nothing stoping it but then again if I was a good chemist I wouldn't be here asking you folks
Attachment: Formic Reduction.pdf (331kB)
This file has been downloaded 709 times
Knowledge is useless to useless people...
"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
|
|
|
Jor
National Hazard
Posts: 950
Registered: 21-11-2007
Member Is Offline
Mood: No Mood
|
|
IIRC sulfuric acid of such concentration would decompose the formic acid to carbon monoxide.
|
|
|
Sedit
International Hazard
Posts: 1939
Registered: 23-11-2008
Member Is Offline
Mood: Manic Expressive
|
|
Ahh yes good point.
Knowledge is useless to useless people...
"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
|
|
|
Saber
alias Picric-A
Posts: 56
Registered: 6-9-2008
Location: England
Member Is Offline
Mood: vry vry bad mood
|
|
What is the best type of UV light for radical chlroinations?
I understand these work with sunlight however is the UV from blacklights or from those water sterilising tubes better?
thanks,
|
|
|
not_important
International Hazard
Posts: 3873
Registered: 21-7-2006
Member Is Offline
Mood: No Mood
|
|
This has been covered in the threads that discuss making the alpha-chloro-tolulenes. Light in the blue to near UV is the best, for a variety of
reasons. A non-coated (clear bulb) mercury vapor lamp for outdoor lighting applications gives both good wavelengths and high intensity, and is much
more cost effective than the two choices you offered.
|
|
|
Aubrey
Harmless
Posts: 37
Registered: 16-11-2008
Member Is Offline
Mood: No Mood
|
|
Has anyone synthed benzonitrile from benzoic acid and sulphamic acid before? I've not seen this preparation described anywhere and am interested in
learning a little more about it
|
|
|
kclo4
National Hazard
Posts: 916
Registered: 11-12-2004
Location:
Member Is Offline
Mood: No Mood
|
|
What is wrong with sciencemadness? I haven't been able to post anything lately and it takes me too the main screen.. has anyone else had that problem?
[Edited on 25-6-2009 by kclo4]
|
|
|
not_important
International Hazard
Posts: 3873
Registered: 21-7-2006
Member Is Offline
Mood: No Mood
|
|
KCLO4 - I had that problem when I tried to post a reply which included a equation in which I'd made a double headed arrow <=> (lesser
than)(equals)(greater than)
I'm pretty sure the < > combination is behind the problem, I had to use the HTML code "& LT ;" "& GT ;" (without the
internal spaces) to get them in this message.
|
|
|
kclo4
National Hazard
Posts: 916
Registered: 11-12-2004
Location:
Member Is Offline
Mood: No Mood
|
|
That must be something with HTML or something, I was posting a link to a google search, and a link to another sciencemadness thread.
Hope the problem can be fixed soon, but seems like it might be hard to diagnose. I noticed it late last night/early morning.
|
|
|
Saber
alias Picric-A
Posts: 56
Registered: 6-9-2008
Location: England
Member Is Offline
Mood: vry vry bad mood
|
|
Has anybody here attempted the monoethanolamine synthesis?
I understand it is made by reacting ethylene oxide (ethene + O2/Ag) with aqueous ammonia, producing a mix of the amines.
I have also read however monoethanolamine reacts with aqueous ammonia to produce diethylamine… Is there any way I can stop this reaction, or how
long does it take?
I understand to produce mainly monoethylamine I must use an excess of ethene oxide…
As for the intended usage, I plan on making some taurine 
|
|
|
12AX7
Post Harlot
Posts: 4803
Registered: 8-3-2005
Location: oscillating
Member Is Offline
Mood: informative
|
|
The classic monoalkylamine synthesis involves phthalimide as a protecting group. Because the two carbonyls polarize it, the N-H is fairly acidic and
the H can be abstracted with potassium carbonate or hydroxide. An electrophile, like ethyl chloride, can substitute easily. The phthalimide is then
hydrolyzed in acid, leaving the monoalkylamine salt.
Not sure if this will work with your particular alkyl. I would suppose the hydroxyl of 2-chloroethanol would sit still, it's less electrophilic. Not
sure how you get it either, add HCl to ethylene oxide maybe? Also sounds hazardous or noxious...
Tim
|
|
|
sparkgap
International Hazard
Posts: 1234
Registered: 16-1-2005
Location: not where you think
Member Is Offline
Mood: chaotropic
|
|
There's also the variation that replaces phthalimide in the Gabriel synthesis with saccharin; go look for the refs yourself, but I do recall that the
saccharin has to be oven-dried for the reaction to work. Otherwise, there's also Delepine (which uses hexamine).
sparky (~_~)
"What's UTFSE? I keep hearing about it, but I can't be arsed to search for the answer..."
|
|
|
Saber
alias Picric-A
Posts: 56
Registered: 6-9-2008
Location: England
Member Is Offline
Mood: vry vry bad mood
|
|
Sorry just figured out my post would not work
I will do a bit more research
[Edited on 27-6-2009 by Saber]
|
|
|
DJF90
International Hazard
Posts: 2266
Registered: 15-12-2007
Location: At the bench
Member Is Offline
Mood: No Mood
|
|
Wikipedia says that the synthesis of taurine starts with 2-hydroxyethanesulfonic acid, obtained from the reaction of ethylene oxide with sodium
bisulfite. From the intermediate compound you might try alcohol => halide (appel reaction? or Sn2 with HI or possibly HCl/ZnCl...) followed by
gabriel or delepine reaction, or you could go alcohol => aldehyde (PCC, oppenauer oxidation, TEMPO, DMP etc...) and then reductive amination
(leuckart, NH4+ HCO2-?) Or alcohol => acid (jones reagent) and then a schmidt reaction (H2SO4/NaN3). Personally the first idea looks most
attractive (I dont think the appel reaction (Ph3P/CCl4) or gabriel synthesis will cause problems with the sulfonic acid group), although you might
have trouble obtaining the reagents.
|
|
|
Sedit
International Hazard
Posts: 1939
Registered: 23-11-2008
Member Is Offline
Mood: Manic Expressive
|
|
Once again I need the wisdom of you folks here.
I was distilling a small amount of bromoethane maybe about 25-35ml and I allowed it to distill to dryness at which point there was a pop and went over
to find the bottom of the flask went out.
I smelled no smell but within couple seconds (10 tops)I could taste a funny taste in my mouth simular to when a funky perfume or something gets
sprayed to close possibly bug spray. It is semi indoors without a fume hood but its well ventilated(few feet from a big wide open garadge door) so I
turned it off and am letting it air out and got the hell out of there.
I know Bromoethane is no good for you...
How concerened should I be long term...short term.... over a small exposure.
I expected this to have a smell of some kind and yet there was nothing but the taste is obvious and not placebo effect.
Knowledge is useless to useless people...
"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
|
|
|
crazyboy
Hazard to Others
Posts: 436
Registered: 31-1-2008
Member Is Offline
Mood: Marginally insane
|
|
"8.1 Single exposure
8.1.1 Inhalation
In a single exposure study, groups of five mice and five rats of each sex were exposed to bromoethane at concentrations of 0, 2800, 5700, 11 000, 23
000, or 45 000 mg/m3 (0, 625, 1250, 2500, 5000, or 10 000 ppm) for 4 h (Roycroft, 1989). Mortalities were observed at 5700 mg/m3 (1250 ppm) or more in
mice and only at 45 000 mg/m3 (10 000 ppm) in rats. At 45 000 mg/m3 (10 000 ppm), clinical signs of toxicity prior to death included dyspnoea,
hyperactivity, and incoordination. No further information was available. LC50 values determined from these data were 21 200 mg/m3 (4681 ppm) for rats
and 12 300 mg/m3 (2723 ppm) for mice.
As a comparison, 1-h LC50 values were calculated as 122 000 mg/m3 (26 986 ppm) for rats and 73 500 mg/m3 (16 230 ppm) for mice (MacEwen & Vernot,
1972). The primary response seen in both rats and mice was central nervous system (CNS) depression, although no further details were given. The
authors reported seeing diarrhoea in rats exposed to the highest concentration, 180 000 mg/m3 (40 000 ppm), and in mice exposed to concentrations
ranging from the highest of 90 000 mg/m3 (20 000 ppm) down to 57 000 mg/m3 (12 600 ppm). (The lowest concentrations used were 90 000 mg/m3 [20 000
ppm] for rats and 45 000 mg/m3 [10 000 ppm] for mice.)
Other LC50 values quoted are 53 000 mg/m3 (11 700 ppm) for rats and 36 000 mg/m3 (7950 ppm) for mice following 2-h exposures, with "general damage to
the nervous system" occurring (Izmerov et al., 1977).
Early, generally poorly reported, studies in mice, guinea-pigs, and cats confirm the toxicity of bromoethane by inhalation (Müller, 1925; Bachem,
1927; Glaser & Frisch, 1929; Sayers & Yant, 1929). In guinea-pigs, for example, toxic signs were observed within 1 min of exposure to 45 000
mg/m3 (10 000 ppm) (Leuze, 1922; Sayers & Yant, 1929; Abreu & Emerson, 1940).
8.1.2 Oral
An oral LD50 of 1350 mg/kg body weight in rats has been listed with no further details (Izmerov et al., 1977), although in another study, Miller &
Haggard (1943) observed "no serious ill effects" in rats from an oral dose of 1200 mg/kg body weight in olive oil.
8.1.3 Dermal
Schwander (1936) reported no signs of toxicity following a study in which an unspecified quantity of liquid bromoethane was placed in direct contact
with the skin of one rabbit for 6 h. "
|
|
|
manimal
Hazard to Others
Posts: 180
Registered: 15-1-2008
Member Is Offline
Mood: ain't even mad
|
|
Since concentrated ammonia solution is so useful but rather scarce, I was thinking that a promising way to prepare it would be to heat intimately
mixed ammonium sulfate and calcium hydroxide in a metal can and pipe the fumes into water.
Any thoughts on this?
Apparently it is possible, but as for yields, I haven't an idea. An interesting Popular Science article recommends it for experimental preparation. http://books.google.com/books?id=mCYDAAAAMBAJ&pg=RA1-PA1...
Reading that, I can see that Popular Science has gone downhill since 1944.
[Edited on 3-7-2009 by manimal]
[Edited on 3-7-2009 by manimal]
|
|
|
| Pages:
1
..
5
6
7
8
9
..
30 |
![[*]](images/xpblue/default_icon.gif){kind=icon}
