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Mixell
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When a bond is created, it releases the equivalent energy of the bond to the environment, right?
So for the reaction to be thermodynamically favorable, the energy of the bonds that are created should exceed the energy of the bonds that are broken?
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Morgan
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Plastics Ben
I have a heavy box of quarter inch thick 6 X 24 inch sheets of a milky white plastic with a glossy surface and paper coating each side to protect from
scratches. But I don't know what kind of plastic it is. It is unaffected by acetone. Any ideas what tests I could do to determine the plastic?
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watson.fawkes
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Quote: Originally posted by Morgan  | | I have a heavy box of quarter inch thick 6 X 24 inch sheets of a milky white plastic with a glossy surface and paper coating each side to protect from
scratches. But I don't know what kind of plastic it is. It is unaffected by acetone. Any ideas what tests I could do to determine the plastic?
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It's most likely to be an acrylic polymer, as that's the bulk of tinted sheet plastic out there. Second most
likely is polycarbonate, but I don't often see it tinted in trade.
Do you want to know the chemical composition for using it as a reagent, or do you want to select an adhesive, or something else?
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Morgan
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It was just some plastic leftover from a photography business where they would mount pictures to it and then cut around the figures with a bandsaw
making little statues of a sort of people, pets, etc.
I thought I might find some use for it but wanted to know if it was acrylic or polycarbonate, my two guesses as well. I have been playing around with
electrostatics lately and might use it in some way.
I could make one of these only 6 inches instead of CD size.
http://www.youtube.com/watch?v=R9JVSWfgleg
Or perhaps as a plastic base for an electrophorus if it is a good plastic for that.
http://www.youtube.com/watch?v=TO95iGtRVv0
Or maybe I could employ it as an insulator or structural component It's funny how sneaky high voltage is, how it can crawl over surfaces. I
experienced that with this device I made a few weeks ago. It's odd how entertaining two thin streams of water can be.
http://www.youtube.com/watch?v=h4WvZAVQtjk
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watson.fawkes
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Whatever the chemical
composition, it should be just fine for this. While you'll likely get better performance out of a specialty material, what you've got is good enough
for basic experiments. My only advice is to clean the surfaces carefully before putting the material into service, in case there's a more-conductive
surface coating or residue from the protective paper.
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Mixell
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What is the best way to reduce a solution of palladium nitrate to metallic palladium? May be aluminium metal in conjunction with chloride ions?
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Picric-A
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Benzhydrol Refusing to Crystallise
I reduced 8g of benzophenone with 3g sodium borohydride (1g excess- the borohydride was old and i though better excess than not enough) in 50ml of
methanol. Refluxed for 2 hours then boiled off 25ml of methanol. The remainding cloudy solution was added to 200ml of ice cold water with 50ml of 20%
HCl in.
At this point the benzhydrol should crystallise, instead i got a very slightly yellow oil remaining at the bottom and the aqeous layer went opaque
white.
What is going on here and why is the benzhydrol not crystallising?
I tryed the reaction again on smaller scale and the exact same happened, no crystallisation at all 
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bbartlog
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| Quote: Originally posted by Mixell | | What is the best way to reduce a solution of palladium nitrate to metallic palladium? May be aluminium metal in conjunction with chloride ions?
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I would suggest ascorbic acid. But I don't know what the best way is and suspect it will depend on what you're trying to do. I suspect aluminium might
have problems, either due to passivation or because aluminium nitrate is itself an oxidiser (but this I assume could be addressed by using enough
elemental aluminium).
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Mixell
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Anybody knows what is the color of bismuth nitrate solution?
I would have expected it to be yellow/colorless, bur for some reason mine is green (made from nitric acid and bismuth, which was sold as 99.9%
purity).
I added the nitric acid to the bismuth, and surely, a vigorous reaction has started (, I continued adding nitric acid when the vigorous bubbling had
stopped (at this phase the solution was yellow), then I left it for 10-15 minutes and when I came back, the solution turned green. At the moment a
small amount of bismuth is still dissolving in it, but it has retained its green color.
[Edited on 31-8-2011 by Mixell]
[Edited on 31-8-2011 by Mixell]
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Picric-A
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Green is probably dissolved NO2. This can be dealt by adding small quantities of urea which causes it to give off nitrogen forming the colourless
solution. Alternativly passing a warm stream of air through the solution works.
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Mixell
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After passing large amounts of warm air through the solution, it is still quite yellow-green...
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solo
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Sodium Cyanoborohydride- A highly selective reducing agent for Organic functional groups
Cinto F.Lane
Synthesis
1975; 1975(3): 135-146
DOI: 10.1055/s-1975-23685
.....on page 144 the study talks about the dehalogenation while showing inertness to towards almost all functional groups, I'v iodated my primary
alcohol with Hpo and I2 and resulted with an iodated OH as an HI salt , insoluble in water ....now DMSO can substitute Hexamethylphosphori triamide
(HMPA), ....finally my question how is the w/u with NaCNBH4 not familiar with it , but sure its not the same as with NaBH4....Trying not to kill
myself doing this procedure.....some have suggested using using ammonium chloride to kill the reaction while I thought of using Na2CO3.....I have
searched but not found anything to satisfy me to go on.....thanks....solo
P.S.
I saw this ...."Tetrahydrooxazines 6c,h,i; General Procedure Using Method A
NaBH3CN (0.095 g, 1.5 mmol) was added to a stirred soln of oxazine
4c, 4i, or 4h (0.5 mmol) in AcOH (2.2 mL) under argon. The
mixture was stirred at r.t. for 2 h and poured into a mixture of EtOAc
(100 mL) and sat. Na2CO3 (100 mL). The aqueous phase was backextracted
with EtOAc (2 × 50 mL); the combined organic layers
were washed with brine (50 mL) and dried (Na2SO4). The solvent
was evaporated in vacuo and the residue was subjected to column
chromatography (silica gel).
...source,
Diastereoselective Synthesis of γ-Amino Acids and Their Derivatives from Nitroethane via Intermediacy of 5,6-Dihydro-4H-1,2-oxazines Bearing the
CH2CH(CO2Me)2 Substituent at C3
Alexey Yu. Sukhorukov,
Synthesis
2009(5): 741-754
DOI: 10.1055/s-0028-1083360
http://ifile.it/3kzxacy
....although not the same reaction but the work up makes sense, pick up the organic material with the ethylacetate and kill the boro with the
Na2CO3....but then i may be overreading in order to go forward....still need some input....
Attachment: sodium.cyanoborohydride.pdf (662kB)
This file has been downloaded 641 times
[Edited on 3-9-2011 by solo]
It's better to die on your feet, than live on your knees....Emiliano Zapata.
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Mixell
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Anyone knows what is the full reaction mechanism of dissolution of aluminium in the presence of hydroxide ions? A reference would be great.
Never-mind, managed to dig it up myself, if anyone else is interested: http://www.icnet.dk/alhiref/I0009EDC4.0/DOE%20aluminium_wate...
[Edited on 5-9-2011 by Mixell]
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questions
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temp
Hey guys, here's a random question;
If I were to take an ordinary glass jar (not made from pyrex or anything similar) and submerg it into acetone with dry ice in it at the temperature of
around -77C, would it crack?
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Polverone
Now celebrating 21 years of madness
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Threads Merged
6-9-2011 at 18:57 |
Roger86
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I just saw bitter almond aroma in grocery store, is it same stuff as bitter almond oil, and is there benzaldehyde in it?
edit. did some hard searching in english and found that its ethyl alcohol and propylene glycol and almond aroma.So is almond aroma chemically what?
[Edited on 8-9-2011 by Roger86]
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ScienceSquirrel
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It will almost certainly be a weak solution of benzaldehyde.
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Chemistry Alchemist
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How would I oxidize polystyrene to form styrene?
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solo
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Reference Information
Method of reclaiming styrene and other products from polystyrene based materials
US Patent 6018085
Abstract
A method of reclaiming styrene from polystyrene-containing materials contaminated with animal fats and/or vegetable oils. A solution of polystyrene
from such materials in a solvent is heated in distillation equipment to depolymerize the polystyrene and produce a styrene fraction and a heavier
fraction, the styrene fraction being separated from the heavier fraction. Prior to heating, an inert gas is used to purge the distillation equipment
of oxygen. The method preferably is carried out at the lowest temperature which will achieve the desired rate of depolymerization.
Attachment: Method of reclaiming styrene and other products from polystyrene based materials .pdf (250kB)
This file has been downloaded 626 times
It's better to die on your feet, than live on your knees....Emiliano Zapata.
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Morgan
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Anybody have some information on this product, what combination of chemicals might it be made of?
http://www.uksealants.co.uk/product.asp?idproduct=91
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bfesser
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http://lmgtfy.com/?q=calofer&l=1
Looks like it's primarily sodium silicates. More trouble to separate than it's worth.
I wouldn't recommend using the short questions thread as a substitute for Google.
[Edited on 9/10/11 by bfesser]
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Panache
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| Quote: Originally posted by questions | Hey guys, here's a random question;
If I were to take an ordinary glass jar (not made from pyrex or anything similar) and submerg it into acetone with dry ice in it at the temperature of
around -77C, would it crack? |
depends at what temperature the glass jar is at, if its at -77C, no it won't fail, if its at 400C, yes most likely it will fail. At room temperature
its likely to fail depending on its design, cooling it slowly would minimise the chances of it failing, however it would not stop it smoking
cigarettes, and as we all know, these cause cancer.
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Morgan
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| Quote: Originally posted by bfesser | http://lmgtfy.com/?q=calofer&l=1
Looks like it's primarily sodium silicates. More trouble to separate than it's worth.
I wouldn't recommend using the short questions thread as a substitute for Google.
I spent a few hours reading about K and Na silicates and the hardening process using CO2 or other agents. I had already used Google, imagine that.
It's those other proprietary ingredients I was interested in, kind of a materials science point of view. |
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Roger86
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If a reaction requires Raney nickel catalyst, can it be replaced with really fine powder of nickel, if i expect the reaction to need a lot more
hydrogen?
I read somewhere that it should work, but i'd need 75% more hydrogen, but since hydrogen is dirt cheap, it's not really a problem.
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bbartlog
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Probably depends on just what you mean by 'really fine powder'. I would also expect that the first thing you would need more of is time, not hydrogen,
but without a pointer to whatever it is you read I suppose I'm just guessing.
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Picric-A
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| Quote: Originally posted by Roger86 | If a reaction requires Raney nickel catalyst, can it be replaced with really fine powder of nickel, if i expect the reaction to need a lot more
hydrogen?
I read somewhere that it should work, but i'd need 75% more hydrogen, but since hydrogen is dirt cheap, it's not really a problem.
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Depends on how the 'realy fine' powder has been made. Most fine powders bought commercially have an oxide layer which will prevent hydrogen
adsorbtion, rendering it useless for catalylyst use.
If you find a way of making very fine Ni powder under an inert atmosphear/liquid, then that should be usable as a catalyst.
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