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woelen
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The propylene for me is a nice starter for doing somewhat more organic chemistry. Making the oxide sounds interestng, but as a starter, I can make a
mix of the two stereo isomers of 1,2-dichloropropane. Separating the two enantiomers probably is not within reach of my homelab.
Another interesting direction could be some polymerization experiments.
[Edited on 1-6-13 by woelen]
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plante1999
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Polymerisation of propylene require zieter nigga catalyst, which is out of reach of most member here. I believe only one compound form with chlorine,
however, when you react with water and chlorine. the two variant of chloropropanol are made, which, upon basification and distillation will yield
propylene oxide.
I never asked for this.
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binaryclock
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:/
It doesn't help the fact that I don't know what a nigga catalyst is..
Current Project: Playing with my new Laboy advanced distillery kit!
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plante1999
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What a typo! It is ziegler natta catalyst, sorry.
I never asked for this.
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The_Davster
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Quote: Originally posted by Intergalactic_Captain  | | The only thing I've done with it chemically was an attempt at a mapp vs. acetylene AgNO3 double salt which never worked - And it seems that Axt is
the only one here who ever even attempted that much. |
The silver methylacetylide worked for me as well with MAPP, but it was a very poor energetic.
| Quote: Originally posted by woelen |
I also found quite a few torches, with built in piezo igniter and flame regulator, but I did not yet find a simple regulator, which allows the gas to
flow out of the cylinder into a rubber or PVC tube. I do not want to pay for all the bells and whistles which are on a complete torch system, so I'll
look further.
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When I was playing with MAPP, I used a regular torch head (no piezo) and regulation was by a twistable head. The head could be twisted off
completely, and a tube stuck over it for a perfect fit.
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vmelkon
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They use to sell propylene in one of those small tanks and it was expensive. It was a 300 mL tank and I only saw it at Home Depot (Canada).
I guess MAPP gas is dead. It is now just a marketing term for pure propylene and other gas mixes.
So, how about making some 2-propanol?
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plante1999
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I could easily do that with sulphuric acid and the propylene. I was making, lets say, harder to find compounds...
And also, I runned out of H2SO4 yesterday
I never asked for this.
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woelen
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| Quote: Originally posted by plante1999 | | Polymerisation of propylene require zieter nigga catalyst, which is out of reach of most member here. I believe only one compound form with chlorine,
however, when you react with water and chlorine. the two variant of chloropropanol are made, which, upon basification and distillation will yield
propylene oxide. |
I did not yet study the chemistry of the polymerization reaction. It might indeed be beyond
reach of home chemistry, it just came to mind to me to try that kind of experiments.
With chlorine, I expect two different stereo isomers to form of 1,2 dichloropropane. After addition of chlorine (or bromine) you have a molecule,
which can be written as
CHCl(CH2Cl)(CH3) (or Cl replaced with Br if Br2 is used).
The central C-atom has 4 different groups (H, Cl, CH2Cl, and CH3) attached to it and then there are stereo isomers (think of these isomers as left and
right hand, which are very similar, but are not the same).
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turd
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This does not mean anything as it depends on what you consider as same and similar.
The correct word is enantiomers, which perfectly describes the situation at hand: The molecules are related by isometry (a distance
preserving function), but not by proper rotations. That means that the molecules have exactly the same inter-atomic distances, angles and in
consequence energy and therefore - in an anisotropic environment - behave exactly the same and therefore you could say they are the same.
Now if you put them in a chiral environment, like let's say a polarimeter, then yes, they will behave differently. So you could say they are
different. But you could bring the same argument for two molecules of the same enantiomer with different orientations with respect to for example an
electric field.
So why differentiate between proper rotations (same enatiomer) and improper rotations (different enantiomer). Because to map two molecules of the same
enantiomer onto each other you can slowly rotate them while keeping all interatomic distances the same. To map molecules of different enantiomers at
some point you have to invert one molecule which cannot be decomposed into infinitesimal steps that preserve the molecular geometry.
Conclusion: what is same and what is similar depends heavily on context (and prejudice!) but is never useful to describe anything in itself.
PS: Diasteroemers are also stereo isomers but are not isometric and thus have different interatomic distances and geometries. Yet another level of
similar/same. Thus, stereo isomers is formally correct, but too imprecise in this case.
</rant> 
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woelen
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It is just a matter of semantics. Fact remains that different enantiomers are not the same. A left hand never can be changed into a right hand in 3D
space. You need to mirror the object and such an operation is not possible by allowing translations and rotations only.
Of course, things like boiling point, melting point, color, chemical reactivity are the same for enantiomers, but if you make crystals of different
enantiomers, then these also are mirror objects of each other (unless they have some plane of symmetry, then you cannot distinguish crystals of
different enantiomers).
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unionised
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I don't.
And I think some people have believed that in the past and have been woefully mistaken.
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woelen
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You indeed need protection from suckback. For experiments, the gas flow is adjusted to a very low rate (e.g. in the order of 100 ml per minute) and at
such low rates, suckback is possible. You don't want traces of chlorine or bromine in your gas container. It contaminates your gas and if a little
more is sucked back, then it leads to corrosion of your regulator and possible leaking of the gas from the container.
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vmelkon
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I checked and looks like I have an old cylinder of MAPP gas (propyne and propadiene). What interesting experiments can be done with it? If I pass the
gas through some KMnO4, would propyne turn into a diol?
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plante1999
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I guess it could be brominated and chlorinated in a solvent, but such reactions might be quite dangerous due to the trible bond. Probably not in a
diol, because it have a trible bond, and not a doble bond.
Be safe.
I never asked for this.
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Salmo
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there's something about acetylene iodination in publication, propyne should react in the same way..
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plante1999
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Propylene oxide
Propylene oxide was attempted, but due to the serious lack of suitable distillation equipment, was only partially successful. Pictures were taken, but
found to be quite uninteresting.
50 ml of 10% NaOCl was added in a flask and a propylene flow was passed in it. Time to time, concentrated hydrochloric acid was added in the NaOCl
sol.. At some point, the chlorine produced was all absorbed by the solution, at this point the solution was quite cloudy, mostly all propylene was
absorbed in the solution. When clhlorine was not anymore produced, and the yellow color persisted, the mixture was distilled in a very improvised
ground glass set-up consisting of a short path condenser filled with cold water, a rubber glove as the thermometer stopper and a 50 ml receiving
flask.
After few second of distilliation, a whitish liquid was collected. When the first water clear drop was obtained, the distillation was stopped. The
liquid collected had a alkene smell. The milkish liquid had a lower uncolored layer. The whitish layer dissolved all the way in water to give a clear
solution.
It is believed, that most of the propylene oxide/chloropropanol was distilled while there were produced, lowering the yield.
More work needed.
I never asked for this.
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woelen
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I received my 2 bottles of Map Pro gas and I received the regulator, but unfortunately they do not match. I cannot use the combination. The regulator
is for another type of connection, which is fairly common where I live, but the Map Pro cylinders' connection appears to be very special. I could not
find any place where I live, which carries gas cylinders with that kind of connection, although CGA 600 is supposed to be quite common.
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garage chemist
chemical wizard
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That's unfortunate woelen. I initially also bought two cylinders from this seller but canceled my order when I saw that he wanted EUR 20 for shipping.
I will order from another supplier.
When I find out what kind of regulator fits these bottles I will let you know.
For now, the most obvious solution would be to buy a cheap torch which fits this cylinder.
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woelen
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The only 100% sure source of pure propene is that Italian seller and sellers in the USA and the UK. The problem with pressurized gas is that shipping
is troublesome and this Italian shipper can use road transport. Air-transport of pressurized gas is not possible and none of these UK-based suppliers
ships to locations outside the UK.
The bottles I have from the Italian seller state that the sole ingredient is CAS no. 115-07-1, which indeed is pure propylene. The trouble with all
these hardware-store things is that the true properties of the materials are so uncertain. I now know that Rothenberger's cylinders are pure
propylene, but this need not be the case for other brands who sell similar cylinders with similar names.
I found a German supplier who sells Map/Pro gas and ships to German locations without cost. It might be interesting for you.
http://www.ebay.de/itm/MapGas-Pro-Kartusche-Map-Gas-Mapp-Gas...
It appears to be some Greek source of Map/Pro gas or some similar gas which is marketed as such and I'm not sure about the contents of this gas. The
form factor is the same and it is called Map/Pro, but I cannot find any information on the precise contents of the gas mix in this bottle. Maybe it is
pure propylene, but I'm not sure. Probably it is some low price no-name brand, which tries to mimic Rothenberger and sells cylinders for lower prices,
but these need not be inferior.
For now, I have sufficient of the gas, now I need to find a suitable regulator, but this is harder than I first expected. Unfortnately that same
German seller does not sell torches or regulators for the Map/Pro bottles.
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garage chemist
chemical wizard
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Yes, that's the seller from which I ordered. Free shipping in Germany.
When I have access to the gas I will condense some of it into a cold trap and record a boiling curve during subsequent evaporation. This will tell
without any doubt whether this is pure propylene.
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woelen
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For me there will be no experimenting with the gas for the time being  . I'll keep
the gas bottles and maybe next month or the month after that I'll buy a regulator when I have some budget for scientific stuff again. These regulators
are very expensive and amazingly hard to get where I live.
[Edited on 8-6-13 by woelen]
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Magpie
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The link below shows a regulator that screws onto a CGA-600 male end such as those found on the 400g disposable propane cylinders in the US:
http://www.propane-products.com/index.php?l=product_detail&a...
I have one of these and I use it for my bunsen burner when using propane or MAPP gas. Although I haven't seen a MAP-Pro cylinder end yet I'm betting
it is the same. My particular regulator is stamped "model 6000 Precimex LP gas regulator." It was likely sold under the Mr. Heater brand and I
remember buying it in a BBQ supplies store. Mine has a brass hose barb outlet, however. I'm guessing that the one shown in the link has a brass
orifice. If desired this orifice could likely be removed and replaced with a hose barb. This would take a little handyman work, however.
Also, Avogadro's Lab Supply has one at $45.
The single most important condition for a successful synthesis is good mixing - Nicodem
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woelen
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I finally found a good regulator at the Greek company Tepse. It is a STK-R regulator, sold as part of a kit, called STK-9, which includes the
regulator and torch. The price (incl. 23% VAT) of the regulator plus torch is just below EUR 45 + shipping, which is very cheap compared to other
places, which sell the STK-9 kit.
The STK-R regulator is great. It allows very precise control, you can have a flow of only a fraction of 1 ml per second and you can have a very high
flow and everything in between.
Service of the company is good. Something went wrong during the ordering process (technical issues with the website during order registration), but
after sending a message to the company the issues were resolved immediately. This is the web address:
http://www.tepse.gr/root.en.aspx
The issues may have been caused by my setup (popup blocker in webbrowser).
The regulator and torch are heavy! They are massive brass and together they are at least as heavy as a full cylinder of propylene. The torch is useful
for me as well. It produces a very nice hot flame, ideal for glass blowing, e.g. making ampoules.
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plante1999
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So, you are going to experiment with propylene gas?
I is much harder in europe to get regulators, here it is all the same regulator for non explosive combustible gas such as propylene, propane etc...
I never asked for this.
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Magpie
lab constructor
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| Quote: Originally posted by woelen |
The regulator and torch are heavy! They are massive brass and together they are at least as heavy as a full cylinder of propylene. The torch is useful
for me as well. It produces a very nice hot flame, ideal for glass blowing, e.g. making ampoules.
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I saw this same torch/regulator in use yesterday! I am having my kitchen rebuilt and a plumber was using just such a torch on MAP/Pro gas. The
swiveling and fine pressure regulation were impressive. This is what it looked like although I neglected to look at it closely to get brand/model:
http://www.grainger.com/Grainger/LENOX-Swivel-Torch-4NE79?Pi...
The plumber was very skilled. Here's a picture of his work:
[Edited on 19-6-2013 by Magpie]
The single most important condition for a successful synthesis is good mixing - Nicodem
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