| Pages:
1
..
16
17
18
19
20
..
28 |
Sedit
International Hazard
Posts: 1939
Registered: 23-11-2008
Member Is Offline
Mood: Manic Expressive
|
|
That was perfect Not_important thanks
|
|
|
Klute
International Hazard
Posts: 1378
Registered: 18-10-2006
Location: France
Member Is Offline
Mood: No Mood
|
|
appetsbud,
I have prepared paraformaldehdye from 37% formalin several times, by just vacuum distilling the solution until water distillate slowls down
consoderably, and cooling the resulting thick limpid syrup, which slowly sets to waxy paraformaldehyde. tricky to get out of the flask at first, it
cna be worth directly pouring it hot on a cool thick pyrex dish, and "crushing" it with a spatula tot acheive the granulometry you want. Once cold, it
is very hard to further "grind" or cut up.
I finished by drying it over NaOh or P2O5 to get a very hard white material, which cna then be powdered with a pestle and mortar, but this isn't
practical and it flies everywhere..
here is a picture of the produced paraformaldehdye:
\"You can battle with a demon, you can embrace a demon; what the hell can you do with a fucking spiritual computer?\"
-Alice Parr
|
|
|
sparkgap
International Hazard
Posts: 1234
Registered: 16-1-2005
Location: not where you think
Member Is Offline
Mood: chaotropic
|
|
Apparently my question was missed, so I'm gonna post it again:
| Quote: | | Alright, I will have to ask something after all. I am far away from my Merck Index, so could someone be so kind as to post the whole Merck Index entry
for the antihyperlipidemic acipimox? I am especially looking for synthesis-related references. |
I can't use my Merck Index on a Linux machine  so could someone be so kind?
sparky (~_~)
"What's UTFSE? I keep hearing about it, but I can't be arsed to search for the answer..."
|
|
|
smuv
National Hazard
Posts: 842
Registered: 2-5-2007
Member Is Offline
Mood: Jingoistic
|
|
Acipimox; Merck Index 14th Edition
Monograph Number: 0000111
Title: Acipimox
CAS Registry Number: 51037-30-0
CAS Name: 5-Methylpyrazinecarboxylic acid 4-oxide
Additional Names: 2-carboxy-5-methylpyrazine 4-oxide
Manufacturers' Codes: K-9321
Trademarks: Olbemox (Pharmacia); Olbetam (Pharmacia)
Molecular Formula: C6H6N2O3
Molecular Weight: 154.12
Percent Composition: C 46.76%, H 3.92%, N 18.18%, O 31.14%
Literature References: Prepn: V. Ambrogi et al., DE 2319834; eidem, US 4002750 (1973, 1977 both to Carlo Erba). Prepn and toxicology: eidem, Eur.
J. Med. Chem. 15, 157 (1980). Pharmacological profile: P. P. Lovisolo et al., Pharmacol. Res. Commun. 13, 151, 163 (1981). Pharmacokinetics: L. M.
Fuccella et al., Clin. Pharmacol. Ther. 28, 790 (1980); L. Musatti et al., J. Int. Med. Res. 9, 381 (1981). Mechanism of action: K. Aktories et al.,
Arzneim.-Forsch. 33, 1525 (1983).
Properties: Crystals from water, mp 177-180°. LD50 orally in mice: 3500 mg/kg (Ambrogi).
Melting point: mp 177-180°
Toxicity data: LD50 orally in mice: 3500 mg/kg (Ambrogi)
Therap-Cat: Antilipemic.
Keywords: Antilipemic; Nicotinic Acid Derivatives.
"Titanium tetrachloride…You sly temptress." --Walter Bishop
|
|
|
Sauron
International Hazard
Posts: 5351
Registered: 22-12-2006
Location: Barad-Dur, Mordor
Member Is Offline
Mood: metastable
|
|
Recently someone posted about a chemical-equation writing utility software or applet,
I have tried UTFSE without avail.
Can some one point me to the proper place?
Sic gorgeamus a los subjectatus nunc.
|
|
|
UnintentionalChaos
International Hazard
Posts: 1454
Registered: 9-12-2006
Location: Mars
Member Is Offline
Mood: Nucleophilic
|
|
Sauron, do you mean for drawing out organic reactions? I personally use this freeware: http://www.acdlabs.com/download/chemsk.html
Department of Redundancy Department - Now with paperwork!
'In organic synthesis, we call decomposition products "crap", however this is not a IUPAC approved nomenclature.' -Nicodem
|
|
|
Sauron
International Hazard
Posts: 5351
Registered: 22-12-2006
Location: Barad-Dur, Mordor
Member Is Offline
Mood: metastable
|
|
No, not a 2D structure drawing app. I use MDL ISISDraw for that.
This is something that automatically handles chemical EQUATIONS:
NaOH + HCl -> NaCl + H20
It puts these in bold and subscripts the numbers automatically
Apparently it is a TSR applet.
Sic gorgeamus a los subjectatus nunc.
|
|
|
DJF90
International Hazard
Posts: 2266
Registered: 15-12-2007
Location: At the bench
Member Is Offline
Mood: No Mood
|
|
I am currently stuck on a question I have come up with. If I were to dehydrate ethanol to ethene using conc. sulphuric acid then what kind of
elimination would this be (E1/E2)?
I dont think it would be E1 because the primary carbocation isn't stable enough, and I dont think E2 can occur because that only happens in basic
conditions (and we need the acid so that the hydroxyl group becomes a good leaving group; water). The only base that could be present is the HSO4-
ion, which I understand works for the case of t-BuOH (its a poor base but an even worse nucleophile), but I E2 needs a strong base to deprotonate a
carbon atom.
After attempting a google search I have come across pages saying the mechaism is E2 (ie. via the carbocation) but these are GCSE help guides and I
dont think that the carbocation is stable enough to be formed.
|
|
|
sparkgap
International Hazard
Posts: 1234
Registered: 16-1-2005
Location: not where you think
Member Is Offline
Mood: chaotropic
|
|
Well, you have to take into account that your concentrated sulfuric acid actually transforms your ethanol first into ethyl hydrogen sulfate,
CH<sub>3</sub>CH<sub>2</sub>-O-SO<sub>2</sub>-OH . So your idea of transforming the -OH group into a better
leaving group is correct.
sparky (~_~)
"What's UTFSE? I keep hearing about it, but I can't be arsed to search for the answer..."
|
|
|
DJF90
International Hazard
Posts: 2266
Registered: 15-12-2007
Location: At the bench
Member Is Offline
Mood: No Mood
|
|
Right, you got a mechanism for the production of the bisulphate ester? I tried to draw it starting with nucleophilic attack of the acid by the alcohol
(like in a fischer esterification) and I had little luck creating a mechanism that seemed likely. From the bisulphite I assume E2 elimination to
occur, with a H being removed off of the methyl group causing creation of the double bond and departure of the bisulphate ion? What is the base that
removes the proton?
Is this the reaction mechanism solely because its a primary alcohol (the sterics of a sec/tert alcohol prevent ester formation?)? I know elimination
from t-BuOH isn't via the bisulphate ester because protonation of OH allows it to leave as water and create a carbocation, which then is deprotonated
by the bisulphite ion thus producing isobutene.
[Edited on 21-1-2009 by DJF90]
|
|
|
raiden
Harmless
Posts: 38
Registered: 4-2-2008
Member Is Offline
Mood: Curious
|
|
Is it possible to dehydrate Aluminium Chloride Hexahydrate by resubliming it?
|
|
|
Sauron
International Hazard
Posts: 5351
Registered: 22-12-2006
Location: Barad-Dur, Mordor
Member Is Offline
Mood: metastable
|
|
Maybe I should move my post to the Short Unanswered Questions thread?
Sic gorgeamus a los subjectatus nunc.
|
|
|
DJF90
International Hazard
Posts: 2266
Registered: 15-12-2007
Location: At the bench
Member Is Offline
Mood: No Mood
|
|
Not something I've seen Sauron. Although it would be a really useful app, especially when you have to write a document with 10^n equations in it.
|
|
|
not_important
International Hazard
Posts: 3873
Registered: 21-7-2006
Member Is Offline
Mood: No Mood
|
|
| Quote: | Originally posted by raiden
Is it possible to dehydrate Aluminium Chloride Hexahydrate by resubliming it? |
No, you can't even just plain sublime it; it loses HCl to form basic chlorides and then Al(OH)3, Al(O)OH, and Al2O3 as heating is continued.
|
|
|
Sauron
International Hazard
Posts: 5351
Registered: 22-12-2006
Location: Barad-Dur, Mordor
Member Is Offline
Mood: metastable
|
|
I saw this on the forum just 3-4 days ago and it appeared to be a fresh post. But I have tried and tried to find it via FSE and nothing turns up.
I search on
writing chemical equations
chemical equation writing
equation writing
writing equations
and each of those appended by "software" or "program"
No results.
Sic gorgeamus a los subjectatus nunc.
|
|
|
DJF90
International Hazard
Posts: 2266
Registered: 15-12-2007
Location: At the bench
Member Is Offline
Mood: No Mood
|
|
http://www.sciencemadness.org/talk/viewthread.php?tid=4268&a...
Post by ayush, 31-12-2008 at 19:16,
| Quote: |
This multifunctional periodic table is an excellent tool for both students and serious researchers. It has over 20 types of data on each element and
all known isotopes in customizable, user-expandable tables. All sixteen numeric data types (plus any user-added data) can be corelated in particle or
line graphs. Includes a powerful chemical equation balancer that can solve the most complex organic reactions and calculate molecular weights and
amounts of reagents.
|
Not exactly what you describe but along the right lines?
|
|
|
Sauron
International Hazard
Posts: 5351
Registered: 22-12-2006
Location: Barad-Dur, Mordor
Member Is Offline
Mood: metastable
|
|
Sorry, nope, that's not it.
Sic gorgeamus a los subjectatus nunc.
|
|
|
Intergalactic_Captain
Hazard to Others
Posts: 227
Registered: 4-9-2004
Location: somewhere where i don\'t know where i am
Member Is Offline
Mood: frabjous
|
|
This may have been answered before, but it's been nagging at me today so I figured I'd ask. How are superconducting magnets, like those in NMR
machines, magnetized? Once they're cooled to a superconducting temperature, is an external magnetic field applied to induce current flow, or is it
induced by some sort of cryogenic voodoo magic?
If you see me running, try to keep up.
|
|
|
not_important
International Hazard
Posts: 3873
Registered: 21-7-2006
Member Is Offline
Mood: No Mood
|
|
They are DC electromagnets - http://en.wikipedia.org/wiki/Superconducting_magnet#Operatio...
|
|
|
497
National Hazard
Posts: 778
Registered: 6-10-2007
Member Is Offline
Mood: HSbF6
|
|
Sauron, I don't know if this is exactly what you mean, but it will balance equations and has some other nice features. I use it quite a bit.
http://home.c2i.net/astandne/help_htm/dwnload1.htm
Oh, I found it, here near the top: https://sciencemadness.org/talk/viewthread.php?tid=4268&...
Now for a question of mine: Can you make nitrite esters of long chain alkanols like dodecanol or cetyl alcohol the same way you make nitrites like
isopropyl nitrite, NaNO2 + HCl? I wonder how well it would work because they're not soluble in water... Maybe with the addition of another solvent to
increase their solubility?
After looking around some more I've found that lauryl alcohol is like 0.0003% soluble in plain water, but when there is some sodium lauryl sulfate
present, its solubility is greatly increased, up to maybe 1 or 2%, which should be plenty for it to react, considering that is how soluble amyl
alcohol is, and it is known to work with the one-pot NaNO2 + acid route.. Here's the ref. The lauryl sulfate should be stable in the conditions right? Hopefully the foaming doesn't become too problematic... fatty
alcohols are used specifically as defoamers after all..
[Edited on 25-1-2009 by 497]
|
|
|
Sedit
International Hazard
Posts: 1939
Registered: 23-11-2008
Member Is Offline
Mood: Manic Expressive
|
|
Does Hydrogen have a disassociation frequency such as chlorine does?
|
|
|
panziandi
Hazard to Others
Posts: 490
Registered: 3-10-2006
Location: UK
Member Is Offline
Mood: Bored
|
|
What the F**K has been up these past 24hrs or so? Sciencemadness had been down, files deleted from server or something?! I felt like a junkie without
smack! Totally distraught and lost amongst the sea of Roguesci! Thank god this is back up now!
|
|
|
not_important
International Hazard
Posts: 3873
Registered: 21-7-2006
Member Is Offline
Mood: No Mood
|
|
| Quote: | Originally posted by Sedit
Does Hydrogen have a disassociation frequency such as chlorine does? |
Yes, way down in the deep ultraviolet, disassociation happening at 840 A or shorter.
http://www.nature.com/nature/journal/v118/n2973/abs/118592c0...
|
|
|
Sedit
International Hazard
Posts: 1939
Registered: 23-11-2008
Member Is Offline
Mood: Manic Expressive
|
|
Thank you.
Once this was accomplished would this cause the hydrogen to behave as it does in the presents of catylist and be useful for hydronation efforts?
A radical hydrogen seems like it could be very useful if it could be produced from the use of light in a reaction vessle.
|
|
|
not_important
International Hazard
Posts: 3873
Registered: 21-7-2006
Member Is Offline
Mood: No Mood
|
|
This - 840 A, the absorption starts at about 1200 A IIRC - is in the extreme or vacuum UV, although a pure nitrogen atmosphere is transparent in the
range. It's not easy to generate much light in this range, and the photons carry a lot of energy - above 10 eV. I suspect that you'd find that most
organics fragment under the required conditions.
|
|
|
| Pages:
1
..
16
17
18
19
20
..
28 |
![[*]](images/xpblue/default_icon.gif){kind=icon}
