Sciencemadness Discussion Board

Total synthesis for beginner

Random - 15-4-2011 at 09:22

I want to attempt some total synthesis of some chemical but I need a suggestion that would be easy to do with OTC chemicals. If there are so much drug total syntheses with OTC chemicals, I am sure there should be something legal that would be easy to do.

ScienceSquirrel - 15-4-2011 at 09:34

What do you have in the way of glassware and chemicals and more importantly experience?
This is my procedure for making ferric ammonium sulphate, it is OTC in most places and requires very little in the way of equipment.


Preparation of Ammonium Iron (III) Sulphate (Ferric Alum)

Experimental

Ferrous sulphate heptahydrate (11.1g, 40mM) was weighed into a 50ml flask. Deionised water (10mL) was added and the mixture was stirred magnetically with gentle warming until the salt had dissolved. Sulphuric acid (90%, 1.8mL, 30mM) was added dropwise and the mixture was placed in a water bath. Hydrogen peroxide (35%, 2.9mL, 30mM) was added dropwise to the stirred mixture. The reaction is vigorous and the reaction mixture goes a muddy brown, clearing to a bright orange as it nears completion.
After the addition the water bath was removed and the mixture was heated for 5 - 10 minutes until effervescence ceased. A solution of ammonium sulphate (2.6g, 20mM) in deionised water (5mL) was added in one portion and the mixture was filtered. The filter paper was washed with deionised water (5mL) and the solution was cooled in an ice salt bath. Pale lilac crystals gradually formed from the deep brown solution. The crystals were filtered off, pressed dry and then allowed to dry in the air. The solid is a pale amethyst in the mass but colourless as small. single crystals. Yield 12.7g, 66%. mp 39-40.5C, Sigma Aldrich catalogue 37-41C.

Discussion

The reaction gives good yields of the alum and could easily be scaled up to produce sufficient material to grow a large single crystal.
It is an advantage to keep the mixture slightly acid to avoid the precipitation of ferric hydroxide.

http://www.sciencemadness.org/talk/viewthread.php?tid=5650#p...

Random - 15-4-2011 at 10:14

Thanks for that suggestion, maybe I will try something similar like ferric ammonium citrate which is photosensitive. Though I am looking for some organic total syntheses more than inorganic.

Well, I have some chemicals, phenol, formaldehyde, can make ketones by dry distilation of calcium carboxylates, get some common solvents and some more otc things, all those basic inorganic chemicals (except sulfuric, I could make some weak acid like 3% from so2 and h2o2 or about 10% by electrolysis of copper sulfate)...

Also I can make amides and from them amines from all those easily available carboxylic acids like citric, acetic, fatty acids, benzoic acid..

I could gain experience by trying that reaction in test tubes in small quantities then move to bigger scale.

[Edited on 15-4-2011 by Random]

[Edited on 15-4-2011 by Random]

cyanureeves - 15-4-2011 at 10:31

excuse me ,but what exactly is a water bath? the sulphate and water was warmed then placed in water bath after adding sulfuric acid? i will be trying this all with homemade chemicals except sulfuric acid. i want to see if my ammonium sulfate i made with ammonium hydroxide and epsom salt will work. i followed a method a girl on youtube used to precipitate magnesium hydroxide with ammonium hydroxide and epsom salt. i got about 8 parts ammonium sulfate after i dried solution to 1 part magnesium hydroxide precipitate.my ammonium hydroxide was probably weak and think i got manesium sulfate still because the solution was really heavy.

"Open your eyes and look around some time."

Bot0nist - 15-4-2011 at 10:32

There are many very workable synths on this forum if you look. Since coming here I have made, copper sulfate, nitric acid, cellulose nitrate, peroxides, picric acid, diethyl ether, and many more interesting things. All of these came with help from this forum and its library.

What you can do is only limited to your equipment and your creativity and willingness to learn and research.

ScienceSquirrel - 15-4-2011 at 12:18

Quote: Originally posted by cyanureeves  
excuse me ,but what exactly is a water bath? the sulphate and water was warmed then placed in water bath after adding sulfuric acid? .


The oxidation is quite exothermic so placing the flask in a bowl of cold water acts as a thermal buffer keeping the reaction mixture cool, minimising the decomposition of hydrogen peroxide to water and oxygen.
The excess hydrogen peroxide is then decomposed by heating the solution.
The colour changes in this synthesis are good; a pale green solution goes a bright orange and yields pale violet crystals.
A good product is easily characterised by the pale lilac colour and the form of the crystals which are isomorphic with other alums and the sharp low melting point.
The reactions illustrate a lot of chemistry and if you started from sulphuric acid and steel wool it would be even better.
You have changes in oxidation state and also coordination chemistry; the iron II solution is pale green, the iron III solution is orange yellow and the solid alum is pale lilac.
Make the stuff and draw up a poster explaining the chemistry and it could be a good entry in a school science fair.

Nicodem - 17-4-2011 at 07:00

Quote: Originally posted by Random  
Also I can make amides and from them amines from all those easily available carboxylic acids like citric, acetic, fatty acids, benzoic acid..

Seriously? Please post the procedures. I would like to see how it is done.
Quote:
I could gain experience by trying that reaction in test tubes in small quantities then move to bigger scale.

So you have never done any organic syntheses and have no equipment, but you already want to do total syntheses of natural products? Please get serious, before trying to convince us that you are just trolling. How do you expect anybody will bother helping you progress when you post such things?

Random - 19-4-2011 at 13:12

First I would make ammonium salt of said acid and then heat it to get amide. After that I can get amine from amides by hoffman degradation.


Actually, I have done some of them and some failed, also I need to finish some. For equipment I have jam jars and test tubes. With total synthesis I believe you can learn a lot, because every step is one synthesis.

But now I am not interested in trolling

Nicodem - 19-4-2011 at 13:25

Quote: Originally posted by Random  
First I would make ammonium salt of said acid and then heat it to get amide. After that I can get amine from amides by hoffman degradation.


Actually, I have done some of them and some failed, also I need to finish some.

Please, feel free to post the synthesis details, isolation procedures, characterization data and references.

NurdRage - 20-4-2011 at 20:02

total synthesis of luminol with OTC chemicals

http://www.youtube.com/watch?v=58Ve69s0qD0


I lost months of my life i'll never get back working that out. :(

[Edited on 21-4-2011 by NurdRage]

ItalianChemist - 21-4-2011 at 00:58

You can made some ethyl esters, but you need a reflux condenser and some acid (such as acetic acid, phtalic acid, etc.)
Also the procedure posted by Nurdrage is good, but is quite dangerous for a beginner ;)

[Edited on 21-4-2011 by ItalianChemist]

ScienceSquirrel - 21-4-2011 at 03:12

Quote: Originally posted by NurdRage  
total synthesis of luminol with OTC chemicals

http://www.youtube.com/watch?v=58Ve69s0qD0


I lost months of my life i'll never get back working that out. :(

[Edited on 21-4-2011 by NurdRage]


It is a nice bit of chemistry, why don't you write it up properly?

NurdRage - 21-4-2011 at 05:40

I did,
its the video.

ScienceSquirrel - 21-4-2011 at 06:15

I mean a written description with yields, melting points as characterisation, etc.
This is my description of the synthesis of ferric ammonium sulphate, it tells an experienced chemist everything they need to know to repeat the reaction in a succinct way.

Preparation of Ammonium Iron (III) Sulphate (Ferric Alum)

Experimental

Ferrous sulphate heptahydrate (11.1g, 40mM) was weighed into a 50ml flask. Deionised water (10mL) was added and the mixture was stirred magnetically with gentle warming until the salt had dissolved. Sulphuric acid (90%, 1.8mL, 30mM) was added dropwise and the mixture was placed in a water bath. Hydrogen peroxide (35%, 2.9mL, 30mM) was added dropwise to the stirred mixture. The reaction is vigorous and the reaction mixture goes a muddy brown, clearing to a bright orange as it nears completion.
After the addition the water bath was removed and the mixture was heated for 5 - 10 minutes until effervescence ceased. A solution of ammonium sulphate (2.6g, 20mM) in deionised water (5mL) was added in one portion and the mixture was filtered. The filter paper was washed with deionised water (5mL) and the solution was cooled in an ice salt bath. Pale lilac crystals gradually formed from the deep brown solution. The crystals were filtered off, pressed dry and then allowed to dry in the air. The solid is a pale amethyst in the mass but colourless as small. single crystals. Yield 12.7g, 66%. mp 39-40.5C, Sigma Aldrich catalogue 37-41C.

If I wanted to repeat your synthesis of luminol I would have to watch the video taking notes, then do a lot of calculations, look things up, etc before I could start work.

ItalianChemist - 21-4-2011 at 06:26

Quote: Originally posted by NurdRage  
I did,
its the video.

Final yeld?
I'll try this starting from pthalic anhydride and nitrating it with HNO3 65% and H2SO4 96%

NurdRage - 21-4-2011 at 07:28

@ScienceSquirrel
So you want me to post a slide show of text? I don't think that's the point of youtube video.

But if you really REALLY want it, i'll see what i can do.

@ItalianChemist 200mg


[Edited on 21-4-2011 by NurdRage]

ScienceSquirrel - 21-4-2011 at 08:30

Quote: Originally posted by NurdRage  
@ScienceSquirrel
So you want me to post a slide show of text? I don't think that's the point of youtube video.

@ItalianChemist 200mg

[Edited on 21-4-2011 by NurdRage]


Have alook at this example;

http://www.sciencemadness.org/talk/viewthread.php?tid=14359

If I wanted to repeat that I could.
All the amounts are laid out for me, the products are characterised, etc, etc.
If I wanted to have a go at your synthesis using your video I might as well almost start from scratch.
You tube videos are OK for frying eggs and bacon but I do not see them as cutting the mustard for organic synthesis.
If you have ambitions of being a serious scientist one day then it is time to start learning to write up experiments.
Universities do not accept you tube videos as lab reports to my knowledge!

NurdRage - 21-4-2011 at 08:35

Do you want a slideshow or not?

I don't think universities would take postings on a message board either.

[Edited on 21-4-2011 by NurdRage]

ScienceSquirrel - 21-4-2011 at 08:48

Quote: Originally posted by NurdRage  
Do you want a slideshow or not?

I don't think universities would take postings on a message board either.

[Edited on 21-4-2011 by NurdRage]


He could copy his posting, paste it in to a word processing program, format it and submit it as a lab report.
Try doing that with your video!
If you make up a slideshow I will still have to sit through it taking notes and then figuring it out for myself.
You have no molar ratios, very few yields, no melting points or literature values, sometimes you do not even tell us the amount used.

NurdRage - 21-4-2011 at 08:49

If you don't want a slide show, where i am i supposed to put it? (the write up)
Why am i required to put it on sciencemadness?


[Edited on 21-4-2011 by NurdRage]

bfesser - 21-4-2011 at 09:35

Every time I see the thread title I think to myself, "Ooh! A serious thread on total synthesis." Then I remember that it's really just a flame war with an inappropriate title. Disappointing. Please, look up the term <em>Total Synthesis</em> somewhere. As I understand it, the targets are complex organic molecules (often natural products), not trivial inorganic salts. Then again, I could be totally clueless.

Just an example:
<a href="http://en.wikipedia.org/wiki/Quinine_total_synthesis">Wikipedia article on the total synthesis of Quinine</a>

ScienceSquirrel, are you intentionally trying to come off as a narcissist?

[Edited on 7/9/13 by bfesser]

#maverick# - 21-4-2011 at 11:51

Quote: Originally posted by NurdRage  
If you don't want a slide show, where i am i supposed to put it? (the write up)
Why am i required to put it on sciencemadness?


[Edited on 21-4-2011 by NurdRage]


nah mate what i think he is trying to say is that if you put it in like a word document in a lab report style it would be easier for others to replicate. btw i love your videos they have been really helpful in helping me with some synthesis.


Just My .02 cents

ScienceSquirrel - 21-4-2011 at 12:01

The synthesis of quinine before the existence of much in the way of instrumental analysis involved the efforts of hundreds of chemists over a 150 year period and huge resources.
The final synthesis by Woodward and Doering was part of the US war effort in the 1940's, it built on decades of work and used relay compounds that had been previously characterised by other chemists.
Most home chemists are limited to comparing crystal shape, a melting point if you are lucky and maybe TLC.
They have less in the way of resources than Woodward and Doering in the 1940's.
Making anything in a good yield and showing that you have what you claim to have in reasonable purity can be a challenge.
If bfesser wants a simple problem to show how good he is, he can tell us how a home chemist would show that a sample of potassium chlorate prepared by a home chemist is better than 97% as opposed to 90%.
I said that I thought that NurdRage's chemistry was good but it was let down by the presentation as a video and a lack of experimental detail.
I did not insult or flame him


bfesser - 21-4-2011 at 18:34

Quote: Originally posted by ScienceSquirrel  
If bfesser wants a simple problem to show how good he is, he can tell us how a home chemist would show that a sample of potassium chlorate prepared by a home chemist is better than 97% as opposed to 90%.


I'm sorry, but I have no idea what you're talking about here. Perhaps we could continue this off-topic discussion via PM?