| Pages:
1
..
28
29
30 |
the Z man
Harmless
Posts: 28
Registered: 13-6-2010
Member Is Offline
Mood: No Mood
|
|
Is it possible to make lead nitrate by adding NH4NO3 to lead acetate solution, boiling down to destroy the ammonium acetate into acetamide and
precipitate the Pb nitrate with alcohol? Then what is a way to destroy acetamide with simple chemicals as I don't want to throw down the drain a
carcinogen? I know it's a weird way to Pb(NO3)2 but i couldn't get other methods to work.
|
|
|
JohnWW
International Hazard
Posts: 2849
Registered: 27-7-2004
Location: New Zealand
Member Is Offline
Mood: No Mood
|
|
Being an oxidizing acid, HNO3 should be able to dissolve Pb metal, in spite of being below H in the electrochemical series. Have you tried that?
|
|
|
the Z man
Harmless
Posts: 28
Registered: 13-6-2010
Member Is Offline
Mood: No Mood
|
|
It would be much easier if I could get nitric acid  I also tried to precipitate it
as hydroxide and react with ammonium nitate solution but I got a very little yield of white precipitate, even if I used large excess of hydroxide and
when I tried to dissolve the precipitate in the boiling AN solution it didn't want to dissolve 
|
|
|
d010060002
Harmless
Posts: 11
Registered: 5-7-2010
Member Is Offline
Mood: No Mood
|
|
I've been doing some simple electrolysis of water, with a PC power suppply giving 6 volts at 1.3 amps DC. I've been using spectroscopic carbons as
both the anode and the cathode, and it takes me about a day to get one bottle of hydrogen (15 hours or so). I asked by physics teacher what i could
do to increase the speed of the electrolysis, and he said that I could either increase the current or that I might have reached the limit of the
surface area on the rods, and should add more. I'm just wondering if it's possible to run out of surface area on a rod/ if there's a way or finding
out if i have.
Thanks
|
|
|
solo
International Hazard
Posts: 3975
Registered: 9-12-2002
Location: Estados Unidos de La Republica Mexicana
Member Is Offline
Mood: ....getting old and drowning in a sea of knowledge
|
|
In the Study posted they use THF as the solvent....first of all what is it's purpose in the reaction and can it be substituted by Chloroform or
benzene or suggest something else, since i have no source of THF for this exploratory reaction.....thanks
Reductive Dehalogenation of Arylhalides and Alkylhalides with Zinc in
THF Saturated Aqueous Ammonium Chloride
Rahim Hekmatshoar,* Sodeh Sajadi and Majid M. Heravi
Journal of the Chinese Chemical Society
2008, 55, 616-618
Abstract
Alow-cost and highly effective zinc/THF-saturated aqueous ammonium chloride has been developed
for dehalogenation of arylhalides and alkylhalides in aqueous systems.
Keywords: Reductive dehalogenation; Zinc; Aqueous ammonium chloride.
Excerpt
Reductive dehalogenation: General procedure Compound 1-12 (1 mmol) was added to an excess
amount of zinc powder (0.260 g, 4 mmol) in saturated aqueous ammonium chloride (4 mL) and THF (2 mL) and
the mixture was stirred at room temperature; after 3-5 h the Zn powder had disappeared (Table 1). Unreacted zinc was separated and washed with water.
Two phases of solution were extracted and then the solvent was evaporated and further purification was performed by flash chromatography to yield
products.
[Edited on 15-7-2010 by solo]
Attachment: Reductive Dehalogenation of Arylhalides and Alkylhalides with Zinc ....pdf (60kB)
This file has been downloaded 976 times
It's better to die on your feet, than live on your knees....Emiliano Zapata.
|
|
|
jokull
National Hazard
Posts: 506
Registered: 22-2-2006
Location: Everywhere
Member Is Offline
Mood: Ice glassed
|
|
In general terms, THF acts as a nucleophile in dehalogenation reactions. For the system you are interested in, THF is highly miscible with water
(intended as protic solvent). Maybe you can use a mixture of short alcohols and ethers.
|
|
|
mewrox99
Hazard to Others
Posts: 321
Registered: 7-6-2010
Location: New Zealand
Member Is Offline
Mood: No Mood
|
|
Is there any easy way to turn perchlorate into chlorate
|
|
|
JohnWW
International Hazard
Posts: 2849
Registered: 27-7-2004
Location: New Zealand
Member Is Offline
Mood: No Mood
|
|
Why would you want to reduce perchlorate to chlorate, when the latter is so much more dangerous to handle, and perchlorate is more powerful as an
explosive when it is detonated? Or perhaps you want to use some chlorate as an herbicide, especially to kill stubborn spreading grasses like kikuyu?
For the latter purpose, farm supplies stores, such as RD1 and Wrightsons and CRT in New Zealand, may have a "technical grade" of it; I remember my
father buying some around 1960 to kill some kikuyu, but that was before Roundup (which is not completely effective against kikuyu) became widely
available.
[Edited on 16-7-10 by JohnWW]
|
|
|
mewrox99
Hazard to Others
Posts: 321
Registered: 7-6-2010
Location: New Zealand
Member Is Offline
Mood: No Mood
|
|
It's a fairly atypical thing to want since most people would much rather have perchlorate than chlorate.
Just wanna play around with it and possibly make a tetraminocopper(II) complex.
Searched there (agricultural suppliers), found nothing
[Edited on 16-7-2010 by mewrox99]
|
|
|
Jimmymajesty
Hazard to Others
Posts: 153
Registered: 9-7-2009
Member Is Offline
Mood: No Mood
|
|
Hi folks!
I want to make acetyl sulphuric acid.
Now the question is not how to make it, rather what properties it has? What can be done with that apart from making diethyl sulphate. Can it be
isolated?
I am planning to lead ketene into sulphuric acid to prepare it. Any info on the substance would be very appreciated, I searched around the net but
found nothing valuable..
|
|
|
Panache
International Hazard
Posts: 1290
Registered: 18-10-2007
Member Is Offline
Mood: Instead of being my deliverance, she had a resemblance to a Kat named Frankenstein
|
|
Is silver powder really a risk to spontaneously combust in air, ie pyrophoric?
|
|
|
watson.fawkes
International Hazard
Posts: 2793
Registered: 16-8-2008
Member Is Offline
Mood: No Mood
|
|
It depends on how small the
particles are. Plenty of metals become pyrophoric when the ratio of surface area to volume is high enough.
|
|
|
12AX7
Post Harlot
Posts: 4803
Registered: 8-3-2005
Location: oscillating
Member Is Offline
Mood: informative
|
|
For a noble metal like silver, that seems rather remarkable. However, several PGMs are also known to be pyrophoric. Supposedly, the high surface
area combined with their catalytic nature makes them particularly reactive; osmium forms the tetroxide spontaneously, though in bulk form, it's inert
as anything.
Nickel is another one, though not a noble metal per se, it's not very reactive in bulk form. This is fairly important because it's pretty easy to
make (thermolysis of the oxalate IIRC) and an important hydrogenation catalyst.
Tim
|
|
|
IrC
International Hazard
Posts: 2710
Registered: 7-3-2005
Location: Eureka
Member Is Offline
Mood: Discovering
|
|
I have to doubt that for silver, I still have an oz of silver dust. No idea particle size but it looks finer than my 500 mesh Al dust. I can pour it
over a table and wait till hell froze over. Sure it will slowly turn black I imagine especially if in an area with H2S or something yet I never saw
any fires. Bought it trying to build a neutron detector using the borated paraffin and GM tube (which has yet to work). I must have a few dozen
neutron emitters I built experimenting around mostly using Be plates and strong alpha emitters yet never have I detected a neutron. Fortunately I know
they do emit neutrons so I store them pointed towards outside walls. You never know sitting in a room for years with these devices in storage right?
Never got into it enough to buy a real detector as those things are expensive. Ni I know also will not go off on it's own as I have 10 pounds of the
dust and it never did anything out of the ordinary either.
Possibly if you created conditions similar to a dust explosion and gave it a match but I would rather not burn my face off nor would I care to waste
valuable madsci materials.
"Science is the belief in the ignorance of the experts" Richard Feynman
|
|
|
chemoleo
Biochemicus Energeticus
Posts: 3005
Registered: 23-7-2003
Location: England Germany
Member Is Offline
Mood: crystalline
|
|
Is there a way to achieve the following reaction
Phe-CHO + X-CH2-CHR2 --> Phe-CH2-O-CH2-CHR2
Note this is formation of a benzyl ether from benzaldehyde... can it be done?
Alternatively, is there good way to start form the benzylalcohol to form the ether? I'd really rather not do the Na salt, that reacts with the halogen
derivative (substitute X for Cl, Br etc).
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
|
|
|
entropy51
Gone, but not forgotten
Posts: 1612
Registered: 30-5-2009
Member Is Offline
Mood: Fissile
|
|
This paper seems to indicate that specially prepared Ag is indeed pyrophoric. I have my doubts about run of the mill Ag powder though.
|
|
|
Nicodem
Super Moderator
Posts: 4230
Registered: 28-12-2004
Member Is Offline
Mood: No Mood
|
|
Quote: Originally posted by chemoleo  | Is there a way to achieve the following reaction
Phe-CHO + X-CH2-CHR2 --> Phe-CH2-O-CH2-CHR2
Note this is formation of a benzyl ether from benzaldehyde... can it be done?
Alternatively, is there good way to start form the benzylalcohol to form the ether? I'd really rather not do the Na salt, that reacts with the halogen
derivative (substitute X for Cl, Br etc). |
Not directly in one step from the benzaldehyde.
You need to use benzyl alcohol and alkylate it with your isobutyl halide (assuming R stands for inert alkyls rather than some groups that might have
some neighbouring effects or having other reactive sites). The reaction is called the Williamson ether synthesis, a simple SN2 substitution, and as
such it would be way more effective (higher yielding and less problematic) if you could reverse the roles of the reaction partners. That is, to
benzylate HO-CH2-CHR2:
PhCH2Br + HO-CH2-CHR2 => PhCH2-O-CH2-CHR2
In any case you need the presence of a non-nucleophilic base. Sodium hydride is indeed commonly employed, but other strong bases work as well (t-BuOK,
K3PO4 in DMF, powdered NaOH or KOH in THF, etc.).
PS: The shorthand "Phe" stands for the phenylalanine amino acid residue. The shorthand for phenyl is "Ph", so benzaldehyde would be "PhCHO" (or "BzH"
by using the benzoyl shorthand).
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
|
|
|
The WiZard is In
International Hazard
Posts: 1617
Registered: 3-4-2010
Member Is Offline
Mood: No Mood
|
|
Just passing through on my way to alt.binaries.pictures.nospam.post-yourself-nude
and thought I would mention this publication which can be DL'd gratis.
DOE-HDBK-1081-94
Primer on Spontaneous Heating and Pyrophoricity
Sorry to say it mentions not silver.
|
|
|
mewrox99
Hazard to Others
Posts: 321
Registered: 7-6-2010
Location: New Zealand
Member Is Offline
Mood: No Mood
|
|
Anyone know what the PiHKAL cover is meant to be? Is it like a mountain or something
|
|
|
Random
International Hazard
Posts: 1120
Registered: 7-5-2010
Location: In ur closet
Member Is Offline
Mood: Energetic
|
|
What is the real reaction between Ca(OH)2(aq) + NaHCO3(aq)?
|
|
|
solo
International Hazard
Posts: 3975
Registered: 9-12-2002
Location: Estados Unidos de La Republica Mexicana
Member Is Offline
Mood: ....getting old and drowning in a sea of knowledge
|
|
I need some assistance in selecting an Abbe refractometer to assist me in my studies of phenethylamines mostly .....as there are many types and scale
and ranges......thanks ,....solo
Addendum. ...i found this
Abbe Refractometers ASTM D 1218. ASTM D 1218, ASTM D 1747, ASTM D 2159 (obs. ... hydrocarbon liquids that have refractive indexes in the range from
1.33 to 1.50, ... the refractive index n20D. (i.e. referred to light of the Sodium ...
..so clearly i need to get something in the range covering maybe from 1.3 to 1.7, but then that is why i need some comments on the matter.
Example:
Phenethylamine
Phenethylamine Structure
Phenethylamine
CAS No. 64-04-0
Chemical Name: Phenethylamine
Synonyms: 2-PHENYLETHYLAMINE;2-AMINOETHYLBENZENE;2-PHENETHYLAMINE;1-AMINO-2-PHENYLETHANE;AKOS BBS-00003597;3-AMINOETHYLBENZENE;LABOTEST-BB
LTBB000487;FEMA 3220;BENZENEETHANAMINE;B-AMINOETHYLBENZENE;AURORA
KA-7805;BETA-PHENYLETHYLAMINE;BETA-PHENETHYLAMINE;(BETA-AMINOETHYL)-BENZENE;B-PHENYLETHYLAMINE;RARECHEM AL BW
0047;PHENETHYLAMINE;1-Phenyl-2-amino-athan;1-Phenyl-2-aminoethane;2-Amino-1-phenylethane
CBNumber: CB0738336
Molecular Formula: C8H11N
Formula Weight: 121.18
MOL File: 64-04-0.mol
Phenethylamine Property
mp : -60 °C
bp : 197-200 °C(lit.)
density : 0.962 g/mL at 20 °C(lit.)
vapor density : 4.18 (vs air)
FEMA : 3220
refractive index : n20/D 1.533(lit.)
Fp : 195 °F
storage temp. : 2-8°C
form : liquid
color : clear, colorless
Water Solubility : SOLUBLE
Merck : 14,7225
BRN : 507488
Stability:: Stable. Combustible. Incompatible with strong oxidizing agents, strong acids.
CAS DataBase Reference: 64-04-0(CAS DataBase Reference)
NIST Chemistry Reference: Benzeneethanamine(64-04-0)
Attachment: petrotest_product_13-0285_en.pdf (373kB)
This file has been downloaded 5100 times
[Edited on 28-7-2010 by solo]
[Edited on 28-7-2010 by solo]
It's better to die on your feet, than live on your knees....Emiliano Zapata.
|
|
|
Nicodem
Super Moderator
Posts: 4230
Registered: 28-12-2004
Member Is Offline
Mood: No Mood
|
|
Ca(OH)2(aq) + NaHCO3(aq) <=> CaCO3(s) + NaOH(aq) + H2O
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
|
|
|
solo
International Hazard
Posts: 3975
Registered: 9-12-2002
Location: Estados Unidos de La Republica Mexicana
Member Is Offline
Mood: ....getting old and drowning in a sea of knowledge
|
|
| Quote: Originally posted by solo | In the Study posted they use THF as the solvent....first of all what is it's purpose in the reaction and can it be substituted by Chloroform or
benzene or suggest something else, since i have no source of THF for this exploratory reaction.....thanks
Reductive Dehalogenation of Arylhalides and Alkylhalides with Zinc in
THF Saturated Aqueous Ammonium Chloride
Rahim Hekmatshoar,* Sodeh Sajadi and Majid M. Heravi
Journal of the Chinese Chemical Society
2008, 55, 616-618
Abstract
Alow-cost and highly effective zinc/THF-saturated aqueous ammonium chloride has been developed
for dehalogenation of arylhalides and alkylhalides in aqueous systems.
Keywords: Reductive dehalogenation; Zinc; Aqueous ammonium chloride.
Excerpt
Reductive dehalogenation: General procedure Compound 1-12 (1 mmol) was added to an excess
amount of zinc powder (0.260 g, 4 mmol) in saturated aqueous ammonium chloride (4 mL) and THF (2 mL) and
the mixture was stirred at room temperature; after 3-5 h the Zn powder had disappeared (Table 1). Unreacted zinc was separated and washed with water.
Two phases of solution were extracted and then the solvent was evaporated and further purification was performed by flash chromatography to yield
products.
|
I was wondering if i can substitute THF with DMSO since they both have similar properties.....
"DMSO is an important polar aprotic solvent. It is less toxic than other members of this class such as dimethylformamide, dimethylacetamide,
N-methyl-2-pyrrolidone, and HMPA. Because of its excellent solvating power, DMSO is frequently used as a solvent for chemical reactions involving
salts, most notably Finkelstein reactions and other nucleophilic substitutions. It is also extensively used as an extractant in biochemistry and cell
biology.[2] Because DMSO is only weakly acidic, it tolerates relatively strong bases and as such has been extensively used in the study of carbanions.
A valuable set of non-aqueous pKa values (C-H, O-H, S-H and N-H acidities) for thousands of organic compounds have been determined in DMSO solution."
It's better to die on your feet, than live on your knees....Emiliano Zapata.
|
|
|
Nicodem
Super Moderator
Posts: 4230
Registered: 28-12-2004
Member Is Offline
Mood: No Mood
|
|
So, this thread became too huge to handle. I'm therefore closing it and opening the third short questions thread.
@Solo: Using DMSO would not be reasonable given its redox properties. THF was used just a cosolvent so try with something more proper, like ethanol
for example. Also, before wasting any expensive substrate make sure to first verify the method by repeating it with one of the substrates reported in
the paper - I have not yet figured why, but for some reason many Iranian papers are often partly fictional or even complete fiction. Your question
about the refractometer is unlikely to get answered, because I doubt there are many still using refractometers in a chemistry lab. As I see it you
will need two of them if you are unable to find one that covers the whole scale.
I guess all other questions were at least partially answered, but if any one feels it missed anything due to this thread manipulation, it is of course
free to pose the unsatisfactorily answered questions again in the new thread and hope for a better reply.
[Edited on 30/7/2010 by Nicodem]
|
|
|
Nicodem
|
Thread Untopped
29-7-2010 at 23:49 |
Nicodem
|
Thread Closed
29-7-2010 at 23:50 |
| Pages:
1
..
28
29
30 |
![[*]](images/xpblue/default_icon.gif){kind=icon}
