Sciencemadness Discussion Board

Reaction Ideas

Chemistry Outreach - 26-3-2012 at 23:42

Dear all,

I'm affiliated with the School of Chemistry at the University of Southampton.

What I'm particularly interested in is obtaining some idea of the kinds of reactions (synthesis or otherwise) that you might be interested in seeing put up on Youtube.

If anyone has any suggestions, please don't hesitate to post them up/ message me and if we get the go-ahead, they'll be uploaded soon.

Thanks in advance!

AndersHoveland - 27-3-2012 at 00:10

Here is one:
http://www.youtube.com/watch?v=gHgyn-wsxFw&list=UUIgKGGJ...
https://www.sciencemadness.org/whisper/viewthread.php?tid=14...
Elemental potassium is made using magnesium powder as the reducing agent. The interesting thing is that magnesium is usually considered to be a less reactive (and weaker reducing agent) than potassium.

You could show a demonstration showing that sulfur is a stronger oxidizing agent than iodine, but then add water and the reaction reverses itself:
http://www.sciencemadness.org/talk/viewthread.php?tid=17604

Or making nitrosyl perchlorate:
http://www.sciencemadness.org/talk/viewthread.php?tid=196

Or if explosives are acceptable, you might try this idea for an interesting possible reaction:
http://www.sciencemadness.org/talk/viewthread.php?tid=19106
(RDX is not really dangerous to make, it is not very sensitive)

AJKOER - 27-3-2012 at 12:26

I think an interesting reaction would be to demonstrate the power of UV light to move the reaction of H2 and Cl2 forward.

http://www.youtube.com/watch?v=NN82GoBG98s

On ignition with a Mg strip:

http://www.youtube.com/watch?v=S0eKJZKfMBg

A reaction that I (and perhaps others interested in alternative fuels for our cars) would find interesting involves bringing NH3 (a suggested alternative fuel with unfortunately lower power than conventional gas) together with Dichlorine Mono-oxide (caution: Cl2O is more toxic than Chlorine and is mildly explosive upon exposure to sunlight, organic compounds, shock and heat). The combination may have the power approaching some conventional employed fuels and requires no ignition mechanism as the gases explode on contact. The exhaust product is potentially recyclable.

The reaction is interesting in the relative amounts of ammonia consumed (or, Cl2O required):

3 Cl2O + 10 NH3 --> 6 NH4Cl + 2 N2 + 3 H2O

Or, with less NH3 available, I would expect:

3 Cl2O + 4 NH3 --> 6 HCl + 2 N2 + 3 H2O

Or, even less:

3 Cl2O + 2 NH3 --> 3 Cl2 + N2 + 3 H2O

as compared to:

3 O2 + 4 NH3 --> 2 N2 + 6 H2O

One method to prepare Cl2O is to add anhydrous Ca(NO3)2 to concentrated Hypochlorous acid (HOCl) thereby extracting water and liberating Cl2O gas as:

Cl2O + H2O <---> 2 HOCl

There are Patents that you can find on the preparation of concentrated HOCl.


[Edited on 27-3-2012 by AJKOER]

Hexavalent - 27-3-2012 at 13:40

I would quite like to see, if possible, lab syntheses of common pharmaceuticals such as, for example, N-(4-hydroxyphenyl)ethanamide (paracetamol) etc., perhaps even from fairly common lab reagents if possible.


Structure of paracetamol, for everybody's reference;




[Edited on 27-3-2012 by Hexavalent]

DJF90 - 27-3-2012 at 15:17

There are plenty of pharmaceuticals that one could make at home if you're interested Hexavalent. Aspirin is the common A-Level synthesis in the UK, as is methyl salicylate (oil of wintergreen) but it isnt much of a far push to make paracetamol if you wish to - the hardest part is obtaining benzene or nitrobenzene to start with, the latter of which is reduced with Zinc and acetic acid (TLC to prevent over-reduction - I have details if you want), treatment of the resulting N-phenylhydroxylamine with acid to effect the Bamberger rearrangement (giving p-aminophenol) and finally acetylation affords paracetamol (this latter step requires acetic anhydride but anilines can be acetylated a more "green" way - I'm sure you'll find something agreeable if you search. A racemic preparation of ibuprofen is a little more tricky and reagent intensive but possible.

I have a digital copy detailing preparation of active ingredients in pharmacueticals (its quite old...) and I'm sure it could be dug out and emailed to you if you'd bother to check your U2U sometime.

GreenD - 27-3-2012 at 18:10

extract eugenol from eugenol with pressurized (liquid) CO2! Nobody seems to know how easy this is.

DJF90 - 28-3-2012 at 02:57

You mean eugenol from cloves with supercritical CO2? This is how alot of coffee is decaffeinated these days, being green and all..

Hexavalent - 28-3-2012 at 07:44

Quote: Originally posted by DJF90  
This is how alot of coffee is decaffeinated these days, being green and all..


It is also used as concerns arise about the use of organic solvents with food and drink, such as DCM.

Chemistry Outreach - 28-3-2012 at 10:01

There's a small selection of videos (including small-scale scCO2 extraction) on our current youtube: http://www.youtube.com/watch?v=o2aIUemy9Xw

I'll get these ideas checked out as soon as possible and hopefully get some stuff uploaded soon! Please keep the ideas coming.

neptunium - 28-3-2012 at 10:43

i`d like to see the isolation of hard to get elements like white phosphorus (in large quantities) or Thallium and of course F2...

[Edited on 28-3-2012 by neptunium]

phlogiston - 28-3-2012 at 14:06

I would also enjoy isolation of certain elements. F2, in particular.

AndersHoveland - 28-3-2012 at 16:32

Reaction of dry ozone with chlorine dioxide. It should form oily red droplets of dichlorine hexoxide.
(ClO2 can be made by passing chlorine gas into sodium chlorite solution)
It is important that both reactant gases be completely free from moisture, otherwise only perchloric acid would form.

AJKOER - 30-3-2012 at 12:09

Quote: Originally posted by AndersHoveland  
Reaction of dry ozone with chlorine dioxide. It should form oily red droplets of dichlorine hexoxide.
(ClO2 can be made by passing chlorine gas into sodium chlorite solution)
It is important that both reactant gases be completely free from moisture, otherwise only perchloric acid would form.


Per Wikipedia:

"High purity chlorine dioxide gas (7.7% in air or nitrogen) can be produced by the Gas:Solid method, which reacts dilute chlorine gas with solid sodium chlorite.

2 NaClO2 + Cl2 → 2 ClO2 + 2 NaCl"

So, since the ClO2 should be dry, perhaps the Gas:Solid method is better starting point for the preparation of the dry ClO2.

Nicodem - 30-3-2012 at 12:29

Quote: Originally posted by DJF90  
There are plenty of pharmaceuticals that one could make at home if you're interested Hexavalent. Aspirin is the common A-Level synthesis in the UK, as is methyl salicylate (oil of wintergreen) but it isnt much of a far push to make paracetamol if you wish to - the hardest part is obtaining benzene or nitrobenzene to start with, the latter of which is reduced with Zinc and acetic acid (TLC to prevent over-reduction - I have details if you want), treatment of the resulting N-phenylhydroxylamine with acid to effect the Bamberger rearrangement (giving p-aminophenol) and finally acetylation affords paracetamol (this latter step requires acetic anhydride but anilines can be acetylated a more "green" way - I'm sure you'll find something agreeable if you search.

A joke-reaction would be the synthesis of paracetamol from aspirin! It is a totally viable reaction, because aspirin can be used for the N-acetylatation of p-aminophenol:
https://www.sciencemadness.org/whisper/viewthread.php?tid=11...
(a bit kewlish perhaps, but those with some sense of irony would appreciate such an experiment)

AJKOER - 30-3-2012 at 14:40

Quote: Originally posted by AJKOER  

A reaction that I (and perhaps others interested in alternative fuels for our cars) would find interesting involves bringing NH3 (a suggested alternative fuel with unfortunately lower power than conventional gas) together with Dichlorine Mono-oxide (caution: Cl2O is more toxic than Chlorine and is mildly explosive upon exposure to sunlight, organic compounds, shock and heat). The combination may have the power approaching some conventional employed fuels and requires no ignition mechanism as the gases explode on contact. The exhaust product is potentially recyclable.

The reaction is interesting in the relative amounts of ammonia consumed (or, Cl2O required):
.......................
Or, even less:

3 Cl2O + 2 NH3 --> 3 Cl2 + N2 + 3 H2O

as compared to:

3 O2 + 4 NH3 --> 2 N2 + 6 H2O


I thought I should add an energy generated by combustion comment. If ones rewrites the last equation quoted above as:

1.5 O2 + 2 NH3 --> N2 + 3 H2O

then the energy released difference between these two reactions is simply the energy produced by the decomposition of 3 moles of Cl2O. This, per my calculations, translates to an increase over the pure oxygen combustion of ammonia reaction by some 31%. Also, one could add a further excess of Cl2O, say 1 mole, and then the reaction produces an energy increase of 42%, 2 moles 52%, 3 moles 63%,...

On the recycling comment, exiting Cl2 can be passed over heated NaOH or Na2CO3 to form more Cl2O, which is then condensed into HOCl (to supply Cl2O).

AndersHoveland - 31-3-2012 at 20:14

You could dissolve gold with a mixture of highly concentrated sulfuric and nitric acids. After all the gold has "disappeared", the dissolved gold in the acid can be transfered and diluted into water, whereupon the gold will reappear back in metallic form! This is much more interesting than aqua regia.
http://www.sciencemadness.org/talk/viewthread.php?tid=17164
(see the thread "dissolving gold in nitric/sulfuric acids")

Eddygp - 1-4-2012 at 05:45

Making salt out of sugar!
3NaClO4 + C6H12O6 = 6H2O + 6CO2 + 3NaCl

EDIT: In aqueous solution

[Edited on 1-2012-4 by Eddygp]

annaandherdad - 1-4-2012 at 05:55

Quote: Originally posted by Chemistry Outreach  
Dear all,

I'm affiliated with the School of Chemistry at the University of Southampton.

What I'm particularly interested in is obtaining some idea of the kinds of reactions (synthesis or otherwise) that you might be interested in seeing put up on Youtube.

If anyone has any suggestions, please don't hesitate to post them up/ message me and if we get the go-ahead, they'll be uploaded soon.

Thanks in advance!


It depends on what kind of audience you're trying to reach. Most of the suggestions I see here would be for a more sophisticated audience. Are you trying to reach high school kids? College students? Amateur chemists?

Eddygp - 1-4-2012 at 08:16

2Na + Cl2 = 2NaCl

'Activate' the reaction by adding a drop of water on the sodium in a chlorine athmosphere.