Sciencemadness Discussion Board

OC Synthesis Candidate

aga - 3-5-2016 at 11:22

I'm imagining something WAY over my level of expertise and think i need a relatively simple organic synthesis that generally ends up as a fairly predictable mixture of ortho/para/meta products to test the idea with.

Preferably nothing lethally toxic, also some reaction where it is relatively easy to determine the % of products in the end result, e.g. colouration, solubility. M.P. etc - basically something i can possibly Do to test the results (i.e. Not GC, Not MS).

Would anyone know of a suitable reaction ?

It's a little bit of an idea in which i Think i can affect the outcome of such a reaction by some nifty electron jiggling with my new-found Quantum-Fu.

[Edited on 3-5-2016 by aga]

Metacelsus - 3-5-2016 at 11:27

Nitration of toluene is pretty simple.

Can you describe more about what you plan to do? (U2U is OK). If it sounds promising enough, I can offer to run a GC-MS on a sample of your product. As it is now, "electron jiggling" "quantum-fu" is very vague, and smells fishy (and I don't mean like amines).

aga - 3-5-2016 at 11:31

At this point it is ground-state-less speculation, so not much to really discuss.

I like the nitration of toluene idea, as i have toluene and nitric acid.

Is it possible to distinguish meta, para and ortho products ?

Edit:

Hang on : this could end up as TNT, which is kinda Toxic, as in Death results if it explodes, same as a Toxin when metabolised.

Death would not help research this idea much.

I'm a TNT virgin, so forgive me if i'm a bit prudish about it.

[Edited on 3-5-2016 by aga]

aga - 3-5-2016 at 12:09

No point being vague i guess. It's not as if i'll ever win the Knobly or anything.

The idea is simply to rig up a reaction vessel with as a strong a magnet as is available at each side, suck the air out, then shove a 25kV charge accross them and continuously strobe the reaction mixture with a low powered laser.

All that whilst doing the normal heating, stiring, reflux etc.

My twisted imagination says that it should lead to some Polarisation of the reacting species, leading to a differential in the proportion of the Products.

No firm idea, just i'd like to try it.

unionised - 3-5-2016 at 12:29

It's certainly possible to get isomers by using polarised light
http://orca.cf.ac.uk/55653/

aga - 3-5-2016 at 12:34

Cool ! So a polarised laser then ...

unionised - 3-5-2016 at 12:45

Circularly polarised...
Good luck.

aga - 3-5-2016 at 12:51

I got to spin it at a consistent frequency ?

Damn.

I'll give it a try anyway, once i have some OC synth i could actually physically do.

blogfast25 - 3-5-2016 at 13:40

I'd warmly recommend a Fischer esterification on maybe 100 - 200 ml scale. Ethyl acetate, e.g.: anh. EtOH + glacial acetic acid + conc. H2SO4 as catalyst.

Not hugely exciting but requires some skill, work-up and yield determination.

a nitrogen rich explosive - 3-5-2016 at 13:52

Ortho-DDNP and para-DDNP?

Volanschemia - 3-5-2016 at 14:10

How about making Phthalic Acid?

You can quite easily end up with all three isomers by oxidizing Xylene (see my OTC Lab Competition entry), and they have an appreciable difference in melting point (207C, 300C, 347C).

[Edit] And it's quite a safe procedure overall.

[Edited on 3-5-2016 by Volanschemia]

j_sum1 - 3-5-2016 at 17:24

Alternatively, nurdrage has just recently posted a vid on chlorotoluene. He says he will follow up soon with a technique for separating the isomers. If you like playing "follow the leader" then you could copy his procedure. And after the first run you could try your polarised light idea to see if you get a different isomer ratio.

XeonTheMGPony - 3-5-2016 at 20:38

Quote: Originally posted by aga  
At this point it is ground-state-less speculation, so not much to really discuss.

I like the nitration of toluene idea, as i have toluene and nitric acid.

Is it possible to distinguish meta, para and ortho products ?

Edit:

Hang on : this could end up as TNT, which is kinda Toxic, as in Death results if it explodes, same as a Toxin when metabolised.

Death would not help research this idea much.

I'm a TNT virgin, so forgive me if i'm a bit prudish about it.

[Edited on 3-5-2016 by aga]


You can burn TNT like a candle, and or drop a anvil on it from 20 feet and it don't go boom, needs a very good kick to pop it off.

The production can have some nasty by products depending on the methods of production.

aga - 3-5-2016 at 22:33

Quote: Originally posted by Volanschemia  
How about making Phthalic Acid?

You can quite easily end up with all three isomers by oxidizing Xylene (see my OTC Lab Competition entry), and they have an appreciable difference in melting point (207C, 300C, 347C).

Good idea. Melting stuff sounds do-able.

The write up of your competition entry is awesome !

Sorry that i had not read it before. Here it is for anybody else who missed it:

http://www.sciencemadness.org/talk/viewthread.php?tid=64317&...

chemplayer... - 4-5-2016 at 03:19

Nitration of toluene is very satisfying (our first ever video). Just be patient, slow and keep it cool. And keep stirring for a while with cooling once the acid is all added!

If you do it properly the chances of forming even di-nitrated products are small.

Separation is done by freezing the washed and dried crude product down. Crystals of p-isomer separate, and you can filter these off and get them quite dry as a fairly pure p-nitrated product.

Only catch is that the p-isomer is soluble to some extent in the o-isomer, so after 3-4 runs of freezing and filtering you'll get few crystals forming but there's still a bit of p-isomer remaining dissolved in the liquid along with the small amount of m-isomer formed.

What is also interesting is the noticeable aroma difference between the p- and o- isomers.

CuReUS - 4-5-2016 at 07:49

why not nitrate aniline with a conc H2SO4/HNO3 mixture ? You would get 2% ortho ,51% para and 47% meta isomers.

aga - 4-5-2016 at 10:19

The key things are these :

1. I'm pretty much a total noob at OC, so it should be an entry-level synth.

2. It should have a predictable range of distinguishable Products.

3. The Products must be separable, again, relatively easily.

4. The Products must be indentifiable/quantifiable by a relative noob.

OK. I've done the wintergreen and ethyl acetate synths, phenolpthalein and other stuff, but very little in total.

Nitrotoluene still sounds scary, mostly because i have Zero experience with it.

Volanschemia's synth looks like a good candidate, although i got no Xylenes.

Guess i could distill some petrol.

[Edited on 4-5-2016 by aga]

Texium - 4-5-2016 at 15:55

Nitration of toluene is actually quite easy, and you can at least purify the p isomer simply by freezing it, which leaves behind roughly 90% o isomer (about 4% m, and some p that will inevitably not freeze) as described by ChemPlayer upthread. Both the p and the o isomers are useful for making other compounds, including a wide range of dyes. It's a good place to start. Also, there's no need to fear TNT being produced. To make TNT, you'd need fuming nitric acid, oleum, and heat. It's certainly not something that you'll make without trying to. Mononitration is done in an ice bath with less concentrated acid, and it's very easy to control.

AvBaeyer - 4-5-2016 at 18:18

aga,

Have look at this site for a list of organic synthesis experiments which range from easy to difficult. I stumbled across this looking for a particular compound preparation. Perhaps it has been posted before but here it is:

http://www.oc-praktikum.de/nop/index.php?page=experiments&am...

Click on the box "show all experiments."

AvB

j_sum1 - 4-5-2016 at 19:18

That looks like a great list. Thanks AvBayer.
I am going to have to peruse that one more closely myself. There will be quite a few that I do not have reagents for but I bet there are some that will be great to push me up the learning curve. And I am pretty confident that aga will feel the same way.

How essential is a rotovap? It seems to be standard equipment for many of these.



[edit]
Hey -- that was my 2000th post!
I guess I should celebrate by posting a question related to the above but still betraying my status as a noob...

I have access to some interesting chemicals that I can save from being thrown out -- some hydroquinone and some metol. I guess they had their origins in photo developing. Now they are destined for the shelf in my lab. I am seeing some interesting phenols in there. With even less OC experience than aga, what kinds of interesting things can I do with these two?

[Edited on 5-5-2016 by j_sum1]

aga - 5-5-2016 at 06:55

Awesome find AvBaeyer !

A quick skim through the synths and i recognise some words ...

... Black Pepper.

Certainly plenty of synths there to have a try at in the near future.

Today's shopping expedition discovered 1litre of Xylenes, some acetone and lots of hypochlorite, so think i'll give Volanschemia's suggestion a try.

Perhaps nitrotoluene after that.

blogfast25 - 5-5-2016 at 07:16

Quote: Originally posted by aga  
discovered 1litre of Xylenes,


xylenes being the operative word:

https://en.wikipedia.org/wiki/Xylene

For Volans' synth you need ortho-xylene, NOT the mixture of three isomers usually sold.

chemplayer... - 5-5-2016 at 07:26

Worth noting that commercial xylene usually also has an appreciable amount of ethylbenzene in as well as the various xylene isomers. We wanted to see if we could prepare phthalic acid in this way (via oxidation) and had a shock on reading the detailed analysis for the commercial material...

aga - 5-5-2016 at 07:39

Mine's probably the same.

The B.P.s are too close for fractional distillation (136 vs 140) although freezing out the p-Xylene looks do-able.

I'll stick some in a flask and bung it in the fridge to find out.

blogfast25 - 5-5-2016 at 08:03

Quote: Originally posted by aga  
Mine's probably the same.

The B.P.s are too close for fractional distillation (136 vs 140) although freezing out the p-Xylene looks do-able.

I'll stick some in a flask and bung it in the fridge to find out.


I'm pessimistic about that. This mixture is a solution of all three components into each other. The very high volubilities make it unlikely that the p-isomer would freeze out.

aga - 5-5-2016 at 11:36

Pessimism may well be appropriate.

I stuck around 200ml in a stoppered FBF, then put it in the 'lab fridge' with a thermocouple taped to the flask.

12.4 C, no change.

Gently agitated the liquid a few times (kicked the fridge) and still nothing.

It's in the freezer at the moment, next to the mini veg spring rolls at about 2 C and still nothing.

aga - 5-5-2016 at 23:29

200ml of mixed xylenes in a domestic freezer (about -4 C) overnight does absolutely nothing.

The water clear liquid appears exactly the same as at room temperature.

Volanschemia - 5-5-2016 at 23:54

Quote: Originally posted by blogfast25  
Quote: Originally posted by aga  
discovered 1litre of Xylenes,


xylenes being the operative word:

https://en.wikipedia.org/wiki/Xylene

For Volans' synth you need ortho-xylene, NOT the mixture of three isomers usually sold.


I thought the point of aga's synthesis was to end up with multiple isomers?
Quote:
i need a relatively simple organic synthesis that generally ends up as a fairly predictable mixture of ortho/para/meta products to test the idea with.


And I did use mixed isomers in my synth, they were separated in converting to Phthalic Anhydride.

[Edited on 6-5-2016 by Volanschemia]

aga - 6-5-2016 at 00:13

Oh !

OK. I'll use this stuff as-is and see what happens.

Volanschemia - 6-5-2016 at 00:29

If you run the Double Benzylic Oxidation on the mixed isomers you will get roughly 20% o-Phthalic Acid, 70% m-Phthalic Acid, 9% p-Phthalic Acid and possibly 1% Benzoic Acid, depending on your source.

Those figures are based on the brand I can buy, so they may vary.