| Pages:
1
..
3
4
5
6
7
..
10 |
gardul
HAZARD TO TEH CATZ!
Posts: 256
Registered: 18-10-2014
Location: Under the Sun in a beaker
Member Is Offline
Mood: Vivified!
|
|
I think I'll be backing outof this since I am far to underskilled for this I Think. Though I will still be donating shortly on payday.
A) I just dont seem to have the time
B) Well I don't think my skills are grand enough to come up with something above the 500g mark. Though I am looking forward in seeing people results.
I just made you read this very pointless signature. How does it feel?
|
|
|
deltaH
Dangerous source of unreferenced speculation
Posts: 1663
Registered: 30-9-2013
Location: South Africa
Member Is Offline
Mood: Heavily protonated
|
|
First off, I would like to state that this is my own personal opinion, I am merely publishing it as food for thought by the judges and for debate.
I think the question of what is a polymer or not deserves closer attention. IUPAC's gold book defines it as:
| Quote: | polymer
A substance composed of macromolecules.(1) |
Now that may seem rather unhelpful and broad. Let's dig further, the word macromolecule in this context is hyperlinked to its own definition, so let's
see what is IUPAC's says about macromolecules?
| Quote: | macromolecule (polymer molecule)
A molecule of high relative molecular mass, the structure of which essentially comprises the multiple repetition of units derived, actually or
conceptually, from molecules of low relative molecular mass.
Notes:
1. In many cases, especially for synthetic polymers, a molecule can be regarded as having a high relative molecular mass if the addition or removal of
one or a few of the units has a negligible effect on the molecular properties. This statement fails in the case of certain macromolecules for which
the properties may be critically dependent on fine details of the molecular structure.
2. If a part or the whole of the molecule has a high relative molecular mass and essentially comprises the multiple repetition of units derived,
actually or conceptually, from molecules of low relative molecular mass, it may be described as either macromolecular or polymeric, or by polymer used
adjectivally.(2) |
Now polymers are disqualified from this contest (and I actually that that was a good idea), but implies that maromolecules are also disqualified.
So there's two parts, it may not be of high relative molecular mass while simultaneously having repeating molecular units. The problem is, what
exactly a high relative molecular mass is, is left undefined 
Let's consider an example: heteropolyacids are built-up of repeating molecular units, for example phosphotungstic acid has 24 tungstate units linked
up in a regular pattern called a keggin structure. It is definitely potentially a macromolecule, but does its molecular mass of 2880.2g/mol
(anhydrous) seal its fate because it is of "high relative molecular mass"?
Also, molecules with some repeating molecules, so long as they are not of "high relative molecular mass" are NOT polymers.
So are oligomers, for example, allowed? Again, at what molecular mass is the cuttoff where repetition puts it into the category of being a
polymer/macromolecule.
I urge the judges to make a cuttoff of some sort.
Since we live in a aspiring metric world of base ten, I suggest that 10 repeating units is the cutoff for where something transcends being oligomeric
to polymeric.
However, me need to translate this to a molecular mass somehow, because that is what IUPAC states it should be based on. Here I suggest we use
tungstate, because it's the heaviest repeating unit that occurs in macromelcules that I know of (as heteropoly acids), that would mean that the
cuttoff should be something like 2500amu (WO4 = 247 *10 = 2470~2500)
That would mean that things like cyclodextrins are in, but heteropolyacids are out.
References:
(1) IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific
Publications, Oxford (1997). XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8.
doi:10.1351/goldbook.
Last update: 2014-02-24; version: 2.3.3.
DOI of this term: doi:10.1351/goldbook.P04735.
(2) IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific
Publications, Oxford (1997). XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8.
doi:10.1351/goldbook.
Last update: 2014-02-24; version: 2.3.3.
DOI of this term: doi:10.1351/goldbook.M03667.
[Edited on 19-11-2014 by deltaH]
|
|
|
j_sum1
Administrator
Posts: 6320
Registered: 4-10-2014
Location: At home
Member Is Offline
Mood: Most of the ducks are in a row
|
|
I thought it was pretty well defined for the purpose of this comp. But maybe it's just my interpretation.
I thought that the synthesis was of a molecule of known molecukar mass. Polymers have indeterminate molecular mass - there is no sense in which all
the molecules are identical mass.
I for one would be impressed if someone synthesised a linear alkane C200H402 and could demonstrate that the product was pure. Now, you could call
that a polymer if you like but if you could show constant molecular mass then I would expect it to qualify (and be a significant challenge.)
Anyway, that's just how I interpreted the challenge.
Watching with interest.
|
|
|
blogfast25
International Hazard
Posts: 10562
Registered: 3-2-2008
Location: Neverland
Member Is Offline
Mood: No Mood
|
|
Not really, and they're not salts in the commonly understood meaning of the term, because they hydrolyse like mad. Certainly SbCl3 can not be seen as
a salt, with an MP of 73 C and a BP of 225 C.
In a solution of SbCl3 the concentration of Sb<sup>3+</sup> is almost infinitesimally small. Unless the alleged Sb ferrocyanide is
extremely insoluble (very low Ks) it would not precipitate in those conditions.
However, the acids of hexacyanoferrate (II) and hexacyanoferrate (III) exist and are water insoluble. The former is
H<sub>4</sub>Fe(CN)<sub>6</sub>, a white insoluble material that precipitates when HCl (e.g.) is added to a solution of
K<sub>4</sub>Fe(CN)<sub>6</sub>.
This is the likely cause of the precipitate: H<sub>4</sub>Fe(CN)<sub>6</sub> formed when you added the acidic
solution of antimony trichloride to the potassium hexacyanoferrate (II) solution.
You can test this with sodium carbonate, maybe even sodium bicarbonate or strong ammonia, which should dissolve the acid (with CO2 evolution in case
of the carbonates).
Quote: Originally posted by deltaH  | Let's consider an example: heteropolyacids are built-up of repeating molecular units, for example phosphotungstic acid has 24 tungstate units linked
up in a regular pattern called a keggin structure. It is definitely potentially a macromolecule, but does its molecular mass of 2880.2g/mol
(anhydrous) seal its fate because it is of "high relative molecular mass"?
|
At 2880 it's a 12W kegging, actually. 12 is the modern understanding. 24 was based on P2O5.24WO3, not PO4.12WO3.
[Edited on 19-11-2014 by blogfast25]
|
|
|
deltaH
Dangerous source of unreferenced speculation
Posts: 1663
Registered: 30-9-2013
Location: South Africa
Member Is Offline
Mood: Heavily protonated
|
|
My bad, you are correct, a little cluck up on my part. It is indeed 12 units.
Actually my brain is soup today because the repeating unit of tungstate is not WO4 but WO3, so that would make my 10 unit molecular weight cut off a
little lower at 10*231.8 = 2318, call it 2300, not 2500.
[Edited on 19-11-2014 by deltaH]
|
|
|
aga
Forum Drunkard
Posts: 7030
Registered: 25-3-2014
Member Is Offline
|
|
I have a feeling that the currently Wining submission may well be disallowed on the same Purity basis that people have mentioned about others.
In the fervent hope that may be the case, i scanned through Brauer's Handbuch and found a couple of big fat candidates on pages 326 and 623, of which
the 326 compound i think i might be able to do...
|
|
|
The Volatile Chemist
International Hazard
Posts: 1981
Registered: 22-3-2014
Location: 'Stil' in the lab...
Member Is Offline
Mood: Copious
|
|
| Quote: Originally posted by aga | I have a feeling that the currently Wining submission may well be disallowed on the same Purity basis that people have mentioned about others.
In the fervent hope that may be the case, i scanned through Brauer's Handbuch and found a couple of big fat candidates on pages 326 and 623, of which
the 326 compound i think i might be able to do... |
Interesting! Looking forward to their posting.
Might do some acetone derivative complex, dunno...
|
|
|
aga
Forum Drunkard
Posts: 7030
Registered: 25-3-2014
Member Is Offline
|
|
Huh ?
No 'dunno', just Do !
If Praxchys's entry gets disallowed, we're in with a chance !
I get the feeling that my first entry could well be disallowed under the rules, so best have a Plan B.
|
|
|
The Volatile Chemist
International Hazard
Posts: 1981
Registered: 22-3-2014
Location: 'Stil' in the lab...
Member Is Offline
Mood: Copious
|
|
| Quote: Originally posted by aga | Huh ?
No 'dunno', just Do !
If Praxchys's entry gets disallowed, we're in with a chance !
I get the feeling that my first entry could well be disallowed under the rules, so best have a Plan B. |
Cool. I've been thinking about some complexig ideas, I'll shoot you some potentially interesting inorganic ligand options.
|
|
|
blogfast25
International Hazard
Posts: 10562
Registered: 3-2-2008
Location: Neverland
Member Is Offline
Mood: No Mood
|
|
Still waiting for Bismuthate's response... 
|
|
|
aga
Forum Drunkard
Posts: 7030
Registered: 25-3-2014
Member Is Offline
|
|
OK.
So are Rador Labs' members allowed to post submissions, despite having Prior Knowledge, and therefore more time, to investigate/research heavy
compounds ?
Surely that would be an Unfair advantage.
|
|
|
blogfast25
International Hazard
Posts: 10562
Registered: 3-2-2008
Location: Neverland
Member Is Offline
Mood: No Mood
|
|
| Quote: Originally posted by aga | OK.
So are Rador Labs' members allowed to post submissions, despite having Prior Knowledge, and therefore more time, to investigate/research heavy
compounds ?
|
I don't really see a problem with it if said member is excluded from adjudication of the winner and if RL in future announces its competition's
subject a fortnight or so before opening the competition. The latter would draw more people in, I think...
[Edited on 22-11-2014 by blogfast25]
|
|
|
bismuthate
National Hazard
Posts: 803
Registered: 28-9-2013
Location: the island of stability
Member Is Offline
Mood: self reacting
|
|
Oh yeah I forgot to post that I decided not to analyze it since I managed to make a larger compound which has been taking quite a while to dry already
so it would be a waste.
Also I'm not in it for the prize.
I can still analyze it later if you want, but I've had my hands full recently.
[Edited on 22-11-2014 by bismuthate]
[Edited on 22-11-2014 by bismuthate]
|
|
|
blogfast25
International Hazard
Posts: 10562
Registered: 3-2-2008
Location: Neverland
Member Is Offline
Mood: No Mood
|
|
If by 'it' you're referring to the alleged 'antimony hexacyanoferrate(II)' I think you should at least test it with a carbonate to see what happens.
SM's pages are google indexed: it's not good to have ambiguous information to allow to stand without corroboration if that information is out there on
the Interwebs.
|
|
|
blogfast25
International Hazard
Posts: 10562
Registered: 3-2-2008
Location: Neverland
Member Is Offline
Mood: No Mood
|
|
| Quote: Originally posted by Oscilllator | Afraid not. That's a polymer with n=10000. Mine is a discrete molecule, 10 points for guessing what it is?
[Edited on 18-11-2014 by Oscilllator] |
I now know what it is. But I'm not telling, there's $19 at stake, ferg-dsake! 
[Edited on 22-11-2014 by blogfast25]
|
|
|
Brain&Force
Hazard to Lanthanides
Posts: 1302
Registered: 13-11-2013
Location: UW-Madison
Member Is Offline
Mood: Incommensurately modulated
|
|
If Rador Labs members win the challenge we're considering rolling the prize over to the next challenge.
Again, this is a test run, so don't be surprised if things get screwy.
At the end of the day, simulating atoms doesn't beat working with the real things...
|
|
|
aga
Forum Drunkard
Posts: 7030
Registered: 25-3-2014
Member Is Offline
|
|
I agree with Blogfast25's comment that so long as any Radar personnel entering the competition are not part of the Judging process, then that would be
fine.
Even Rador people need money,and it;d be a shame to deny them the prize if they won.
|
|
|
Oscilllator
National Hazard
Posts: 659
Registered: 8-10-2012
Location: The aqueous layer
Member Is Offline
Mood: No Mood
|
|
| Quote: Originally posted by blogfast25 | | Quote: Originally posted by Oscilllator | Afraid not. That's a polymer with n=10000. Mine is a discrete molecule, 10 points for guessing what it is?
[Edited on 18-11-2014 by Oscilllator] |
I now know what it is. But I'm not telling, there's $19 at stake, ferg-dsake!
[Edited on 22-11-2014 by blogfast25] |
Shhhhhhhhh
The compound I am thinking of is very easy to make, but I'm finding it nearly impossible to isolate 
|
|
|
Texium
Administrator
Posts: 4580
Registered: 11-1-2014
Location: Salt Lake City
Member Is Offline
Mood: PhD candidate!
|
|
Not
all of us have been considering that...
Sorry people, but if the compound that I've been working on now ends up winning (which is still doubtful), I'm keeping my winnings, because I have no
job and I'm broke! I spent all of my money on chemicals. 
|
|
|
blogfast25
International Hazard
Posts: 10562
Registered: 3-2-2008
Location: Neverland
Member Is Offline
Mood: No Mood
|
|
Yup. To be expected. It's a miracle it crystallises at all.
|
|
|
Texium
Administrator
Posts: 4580
Registered: 11-1-2014
Location: Salt Lake City
Member Is Offline
Mood: PhD candidate!
|
|
If the compound that you're talking about is what I think you're talking about, well, good luck isolating one pure species of it.
|
|
|
Oscilllator
National Hazard
Posts: 659
Registered: 8-10-2012
Location: The aqueous layer
Member Is Offline
Mood: No Mood
|
|
Hmmm, what could it be?
|
|
|
Etaoin Shrdlu
National Hazard
Posts: 724
Registered: 25-12-2013
Location: Wisconsin
Member Is Offline
Mood: Insufferable
|
|
Okay, I get it now. Best of luck with the isolation.
|
|
|
Oscilllator
National Hazard
Posts: 659
Registered: 8-10-2012
Location: The aqueous layer
Member Is Offline
Mood: No Mood
|
|
I know at least one other member is trying to synthesise this compound and so in the interests of fair play I will disclose that I have successfully
used hydrolysed sucrose and sodium metabisulphite to form the complex, forming visually identical products. I don't actually have any of the reagents
that published procedures have used, so at this point I'm just mixing together reagents haphazardly to try and get some results.
|
|
|
bismuthate
National Hazard
Posts: 803
Registered: 28-9-2013
Location: the island of stability
Member Is Offline
Mood: self reacting
|
|
Why not just filter that liquid?
|
|
|
| Pages:
1
..
3
4
5
6
7
..
10 |
![[*]](images/xpblue/default_icon.gif){kind=icon}
