Glycin Synthesis/Production

[brianmquinn]

A dermatologist knows a lot better how to apply this stuff safely than the bottle you accidently drop on your legs. According to Wikipedia, covering 6% of your skin in Chloroacetic Acid can kill you. Another thing that concerns me in these synthesis steps is the need for boiling Ether in sealed glass tubes. If one of these breaks for whatever reason, you might well have an uncontrolled fuel-air explosive going off right in your lab.

Trichloroacetic Acid and Chloroacetic Acid are very similar in name. But as pointed out earlier do not confuse the two when it comes to how toxic they are. I am a scientist and work in a lab with Trichloroacetic Acid and by the name alone I would have thought that Chloroacetic Acid would be less toxic. That would be wrong. I normally consider the MSDS sheets that come with chemicals to be a joke in that they make everything, including sodium chloride, sound super toxic and dangerious. If this case it would be good to read it.

Oh and ether explosions. I've been in a lab for one of those. Glad I was on the other side of the large room when it happened. Nobody hurt except the pride of the one who caused it. He thought he knew what he was doing when it happened.

Just storing a bottle of ether can cause an explosion when the either forms peroxides that are shock sensitive. Sometimes that old bottle of either can explode when you unscrew the lid. That is because the peroxides can form on the underside of the cap. Turning the cap can set them off. If you see any white solid in a bottle of either that has been stored for any amount of time don't open it. Remember sometimes it is under the cap and can't be seen. At least in the USA the more dangerous ethers are stored in metal bottles to lessen the peroxide risk not to make then easier to be seen but because less peroxides from in metal bottles.

 

[Nikola Dulgiarov]

Yes, ether is a b*tch to keep, but commercial ether is supplied with stabilizers added, and up to 5% ethyl alcohol greatly lessens the chance of peroxide formation. Nonetheless, it's not something to fool around with, and even I don't store large samples in my lab.
Now, on to the topic. I have firm reason to believe that the test tube I have with me contains a sample of glycin I only have qualitative tests that may or may not prove to be sufficient to say. What I've done so far is compared paraaminophenol and the sample that I have in the following manner:
Resistance to oxidation: the same amount of material is dissolved in 10% sodium hydroxide and shaken. The pAP quickly turns purplish to brown, whilst mty sample remains in a clear solution with a yellowish tinge.
Treatment with an oxidizer: 50% HNO3 quickly oxidizes the pAP, whilst my sample seems less affected, color indication the same as in the above test
If you have ideas for any other test that can be carried out, I'd be glad to hear you out
Edit: I also ran a melting point/boiling point test that puts the chemical I have within the range of glycin and also accurately defines its behavior at elevated temperatures, i.e: browns at 200C, begins to melt at 220, completely melted at 247-8, decomp.

 

[brianmquinn]

I have not looked up what the melting point should be but if you have crystals and they melt at the proper temp then I say you have a pure and correct product.

Another simple test you could do is TLC (if there is a published method)

 

[Photo Engineer]

Yes, please do not confuse chloroacetic acid with trhchloroacetic acid. Two different beasts.

And be careful in the lab. For those who have seen my lab coat and lab shirt, you know that the coat is NOT good protection. I have holes burned through both of them in the same spot. Also, explosions have a far reach throwing material dozens to hundreds of meters. And fires are rather final as well.

Take care.

PE

 

[Hexavalent]

Just to add to the cautions already mentioned, formulae often omit the side-reactions and by-products, which can be toxic, unstable etc., etc., etc., and not suitable for pouring down the drain.

 

[brianmquinn]

Just to add to the cautions already mentioned, formulae often omit the side-reactions and by-products, which can be toxic, unstable etc., etc., etc., and not suitable for pouring down the drain.

Good point. I remember one side product that caused a lot of trouble when it was released into the enviroment, DIOXIN.

 

[Photo Engineer]

And again, similarities of names should be observed and checked carefully, namely glycin and glycine and dioxin and dioxane. Very different pairs of chemicals with similar names.

PE

 

[Hexavalent]

Ron,

What's that wonderful rhyme about "thought was H20.... no 'mo"?

 

[kb3lms]

Little Willie was a Chemist
but Little Willie is no more
For what he thought was H2O
was H2SO4

 

[brianmquinn]

Yes, ether is a b*tch to keep, but commercial ether is supplied with stabilizers added, and up to 5% ethyl alcohol greatly lessens the chance of peroxide formation. Nonetheless, it's not something to fool around with, and even I don't store large samples in my lab.
Now, on to the topic. I have firm reason to believe that the test tube I have with me contains a sample of glycin I only have qualitative tests that may or may not prove to be sufficient to say. What I've done so far is compared paraaminophenol and the sample that I have in the following manner:
Resistance to oxidation: the same amount of material is dissolved in 10% sodium hydroxide and shaken. The pAP quickly turns purplish to brown, whilst mty sample remains in a clear solution with a yellowish tinge.
Treatment with an oxidizer: 50% HNO3 quickly oxidizes the pAP, whilst my sample seems less affected, color indication the same as in the above test
If you have ideas for any other test that can be carried out, I'd be glad to hear you out
Edit: I also ran a melting point/boiling point test that puts the chemical I have within the range of glycin and also accurately defines its behavior at elevated temperatures, i.e: browns at 200C, begins to melt at 220, completely melted at 247-8, decomp.

In spite of all of the cautions thrown out here I am quite impressed with this post. It really does show intelligence and understanding of chemistry and earlier he listed the safety precautions he was using. How often have we read, “Only do this in a fume hood kids.” Well how many of us actually have access to one? (or a melting point device). Most people that try it would probably just do it in a garage with the door open and maybe a fan on. On line it is hard to tell if someone is competent or not, so I always urge caution. I still do here.

I did my graduate level chemistry under a brilliant man who was near retirement. Some of the most important things he taught me had to do with the mistakes he and others had made over his LONG career. While you may be very smart and well educated there is no substitute for experience in life or the lab. Have fun but don’t get over confident in your knowledge and abilities. I don’t really want to admit how many times I was sure of myself until it went very wrong.

 

[Hexavalent]

That's the one!

Little Willie was a Chemist
but Little Willie is no more
For what he thought was H2O
was H2SO4

 

[Photo Engineer]

Nikola;

For a good intro to Organic Chemistry, read Fieser and Fieser.

PE

 

[Nikola Dulgiarov]

double-post

 

[Nikola Dulgiarov]

PE, thank you for the suggestion, as a matter of fact I was just looking up the list of recommended literature and these will make a neat (and substantial - 25 tomes) addition.
I'm not sure how to verify that I indeed have glycin as a product of my tests yet. Mp is accurate, but the product seems to decompose at a lower temperature, presumably due to impurities. Resistance to areal oxidation is my safest bet so far, literature suggests molybdenium nitrate for a qualitative reaction, but that's not exactly something I can ring up a supplier and ask for. Maybe a solubility test, side-by-side, in Na2SO3 and Na2CO3. I'll think of it tomorrow, after school
Well, I may be in luck - gram quantities of Mo are available from a now-defunct steel mill, so I may be able to do the above test in the following days.

 

[Photo Engineer]

Nicola, I think that MP is a good test even with decomp.

Why not just dry making a small batch of developer? Might work.

Are you the chemistry equivalent of Nicola Tesla?

I have many many more synthetic Org. books to suggest such as books on lab technique. You might try Fuson for lab instruction, Fuson and Snyder for Org. Chem.. and the famous Gould "Mechanism and Structure in Organic Chemistry".

I have more but just cannot locate them OTOMH.

PE

 

[brianmquinn]

. Mp is accurate, but the product seems to decompose at a lower temperature, presumably due to impurities.

I don't know about glycin but there are some compounds that do start to decompose before reaching their melting point. This compound is know to decompose quickly at room temp so I would not be so quick as to say your product is not pure.

 

[Nikola Dulgiarov]

It is suggested that it browns at a temperature below mp and decomposes at bp, so I'd call the test valid, too
I forgot to add that I tested the compound and it is a developing agent, but what should I look for when mixing a batch (i.e. activity in a carbonate alkali, relative induction time, image tone or papers) ?
Thank you for your support and concern
Nick

 

[Photo Engineer]

Nick;

Good glycin is a pure white fine powder. It does brown up with keeping. I have no other guideline to suggest.

PE

 

[Relayer]

If you have ideas for any other test that can be carried out, I'd be glad to hear you out

http://books.google.com.ua/books?id...epage&q=hydroxyphenyl glycine soluble&f=false

To few milligram of compoind add FeCl3 solution. A blue coloured solition is obtained.

PS I search any description or ideas for purification of old "brown" glycine

 

[Nikola Dulgiarov]

Yeah, the above test works for most aromatic compounds with a hydroxyl group, so in most cases it gives a "positive"
As to purification, I can see two things working - a simple water recrystallization, but solubility in boiling water is still too low to make it viable. Secondly, dissolve the glycin in any mineral acid, preferably not a strong oxidizer, and neutralize. For example, warm 15% HCl will gladly dissolve all the glycin I try to put in it. Then, either via an indicator, pH meter, test paper, titrate to a neutral reaction with a base of your choice. Try to keep the amount of acid and base to a minimum so that there isn't a lot of salt to get rid of. Leave overnight in cold water, or icebath, or cooler at 5-10C. Filter and wash the precipitate with 2 parts water (you can wash as much as you like, but the minimal amount of salt remaining isn't fatal). Dry and either make up a stock solution in 1% Na2SO3 and 3%Na2CO3, or store in a vacuum-sealed envelope
As to my progress. I feel that I have done what I wanted to, and my last test had a yield of 75% of the theoretical ( the remainder was left in the filtrate, as i hurried too much and shortened crystallization 4x.) The approach I took is analogous to the production of N-phenylglycine from aniline, whereby a derivative of MCA is used to prevent the formation of the pAP.HCl salt. Well, that is all there is to say. Case closed I'd like to thank all of you, who gave me reasonable advice and warning, and in particular to Rudi, who translated Vater's article and referenced me to the German patent I was looking for. Thank you

 

[Nikola Dulgiarov]

PS: Relayer, the above purification procedure is based on my experiences and may not prove useful for old, brown glycin. Try it on a quarter of a gram or so, as a proof of concept, before running a larger batch.

 

[Relayer]

Nikola, thank you. Week ago I was try purification of glycin via dissolve in 20% H2SO4 and titration. Yes, it working, but result isn't have same activity as fresh glycin. I found that glycin soluble in EtOAc (Ethyl acetate). Maybe try this way later.

 

[Nikola Dulgiarov]

You can try the reverse, precipitating it from a basic solution with acetic acid, which doesn't dissolve as much glycin as the mineral acids. Activitywise, I am unable to make a claim.

 

[Photo Engineer]

Here is a thought for testing. Either IR (Infra Red) or NMR (Nuclear Magnetic Resonance) will do the trick. If a local school has either unit, a simple 10 minute test on either will reveal the nature (and possible purity including contaminants) of your material. I can't hurt to ask someone.

There are huge textbooks of spectra out there that will also help.

PE

 

[Athiril]

Edit: Ours is $55/100g I think, I was thinking of catechol before, we have cheap catechol.