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Author: Subject: How to remove salt from putrescine dihydrochloride?
Freddyhampt
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[*] posted on 18-9-2017 at 04:20
How to remove salt from putrescine dihydrochloride?


What is a simple method to remove the dihydrochloride from putrescine dihydrochloride? In other words, if we begin with putrescine dihydrochloride in solid form what steps are involved in conversion to just putrescine?

I have been experimenting with sodium hydroxide and ethanol but my procedure must be wrong because the putrescine seems to stay in salt form. I am a complete novice however.

A step by step description of any ideas would be greatly appreciated. Thank you in advance.

[Edited on 18-9-2017 by Freddyhampt]

[Edited on 18-9-2017 by Freddyhampt]
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[*] posted on 18-9-2017 at 16:06


Treatment with sodium hydroxide should work fine. When you attempted it before, what procedure did you follow, specifically?



As below, so above.
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[*] posted on 18-9-2017 at 17:17


Quote: Originally posted by Metacelsus  
Treatment with sodium hydroxide should work fine. When you attempted it before, what procedure did you follow, specifically?


Thanks for the reply. I have sincerly tried to find the process online but have had little luck so I hoped random experimenting would work. It did not.

I dissolved the putrescine dihydrochloride in ethanol, then added sodium hydroxide powder. The NaOH did not disolve, so...

I did the same as above but first put the NaOH in solution. Still nothing. So...

I tried to get the pH of the putrescine/NaOH mixture to 11 or 12 by using an electronic pH meter but had strange results. I added a little NaOH and the pH went up to 10, so I added more NaOH but the more NaOH I added the pH would not climb to 11 or 12. The meter did not max out, it bounced around the 9 or 10 range, but never got pinned to a max pH.

Why the pH meter did this I do not understand. Must I use only pH test strips?

I believe I should create a 6M solution of NaOH and it dropwise to the putrescine dihydrochloride, correct? Until it reaches a pH of 11 or 12, correct? Will this cause the dihydrochloride to separate from the putrescine? But should ethanol be mixed with the NAOH solution before adding to the putrescine dihydrochloride? Is that 'basified ethanol'? Should that ethanol/NaOH mixture be 11 or 12 pH first before adding to the putrescine dihydrochloride? Or a different way? I have not measured quanties yet, but do have the capability to do so. If I had more info I will do just that.

Thank you again.


[Edited on 19-9-2017 by Freddyhampt]
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[*] posted on 18-9-2017 at 17:24


Putrescine dihydrochloride should be readily soluble in water, no?
I don't see why ethanol should be necesary, the procedure you say you think you should use (without ethanol) seems fine. Perhaps gentle heat might help in forming the freebase amine.
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[*] posted on 19-9-2017 at 00:35


The pH effect you got is simply the trimming/buffer effect.
Putrescine is 1,4-diamino-butane... it display two basic groups per molecules
H2N-CH2-CH2-CH2-CH2-NH2 + HCl <--==> ClH3N-CH2-CH2-CH2-CH2-NH2 (or H2N-CH2-CH2-CH2-CH2-NH2.HCl) (monohydrochloride)
ClH3N-CH2-CH2-CH2-CH2-NH2 + HCl <--==> ClH3N-CH2-CH2-CH2-CH2-NH3Cl (or H2N-CH2-CH2-CH2-CH2-NH2.2 HCl - dihydrochloride)

The buffer effect is expressed when you have a free base and its salt together into solution (or a free acid and its salt together into solution); it expresses when the concentration ratio salt/base or salt/acid ranks from 1/10 to 10/1; usually the pH is "blocked" arround the value of the pKa (thus + or - 1 with regard to the 1/10 (0,1) to 10/1 (10) ratio).

Here NH2-CH2-CH2-CH2-CH2-NH2 is the free base of NH2-CH2-CH2-CH2-CH2-NH2.HCl
NH2-CH2-CH2-CH2-CH2-NH2.HCl is the free base of NH2-CH2-CH2-CH2-CH2-NH2.2 HCl

conversely
NH2-CH2-CH2-CH2-CH2-NH2.2 HCl is the acidic form of NH2-CH2-CH2-CH2-CH2-NH2.HCl

So you must have a trimming effect/buffer effect for both pKa's of the diaminobutane...
==> The second one should be (I don't have the precise value but it must be 3 to 4 pKa units lower than the first one) arround 6 (+/-1 that is pH 5-7);
==> The first one should be arround 10,8 (+/-1 thus pH 11,8-9,8... what you observed)

Note that pH-meters/ metry is usually done into water alone... into a mix of water/ethanol or ethanol alone the measures may provide strange readings.

NaOH is quite soluble into ethanol...
I suspect your procedure calls for addition of saturated NaOH/ethanol solution to a saturated diaminobutane dihydrochloride/ethanol; in principle when stoechiometric amounts are used, one should get the free base in solution into ethanol and a precipitate of solid NaCl (plus a little water formed into the neutralization process).

***********
To me it would be best (although stinky... putrescine smell like dead meat/zombie (just like cadaverine (diaminopentane; hence their special alchemist names):
Do this into an expandable recipient/reactor (NaOH will ruin any glassware upon heating; the glass will be corroded and become opaque/white); the distillation device must be hermetically closeable (except if you wish to get all dead meat eater arround and smell like the morgue/mortuary.
1°) Add DAB (diaminobutane) dihydrochloride to warm water (about 1g/10 ml)
2°) Add excess saturated NaOH/H2O solution and mix the two (it should warm up a little since it is a neutralization and this produces a lot of heat tempered a little by the initial water
3°) Distil... only DAB and water will pass over (no need of a multiple step/plate distillator... only one plate (a tube) is sufficient (like an alchemistry horn / retort)... water, NaOH and NaCl will remain into the initial flask (aside with Na silicate from dissolving the glassware).

Enjoy ;)


[Edited on 19-9-2017 by PHILOU Zrealone]




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[*] posted on 19-9-2017 at 02:56


Quote: Originally posted by Elemental Phosphorus  
Putrescine dihydrochloride should be readily soluble in water, no?
I don't see why ethanol should be necesary, the procedure you say you think you should use (without ethanol) seems fine. Perhaps gentle heat might help in forming the freebase amine.


Yes, definintely soluble in water. I will try gentle heat and report my findings, thank you.

[Edited on 19-9-2017 by Freddyhampt]
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[*] posted on 19-9-2017 at 03:03


Quote: Originally posted by PHILOU Zrealone  
The pH effect you got is simply the trimming/buffer effect.
Putrescine is 1,4-diamino-butane... it display two basic groups per molecules
H2N-CH2-CH2-CH2-CH2-NH2 + HCl <--==> ClH3N-CH2-CH2-CH2-CH2-NH2 (or H2N-CH2-CH2-CH2-CH2-NH2.HCl) (monohydrochloride)
ClH3N-CH2-CH2-CH2-CH2-NH2 + HCl <--==> ClH3N-CH2-CH2-CH2-CH2-NH3Cl (or H2N-CH2-CH2-CH2-CH2-NH2.2 HCl - dihydrochloride)

The buffer effect is expressed when you have a free base and its salt together into solution (or a free acid and its salt together into solution); it expresses when the concentration ratio salt/base or salt/acid ranks from 1/10 to 10/1; usually the pH is "blocked" arround the value of the pKa (thus + or - 1 with regard to the 1/10 (0,1) to 10/1 (10) ratio).

Here NH2-CH2-CH2-CH2-CH2-NH2 is the free base of NH2-CH2-CH2-CH2-CH2-NH2.HCl
NH2-CH2-CH2-CH2-CH2-NH2.HCl is the free base of NH2-CH2-CH2-CH2-CH2-NH2.2 HCl

conversely
NH2-CH2-CH2-CH2-CH2-NH2.2 HCl is the acidic form of NH2-CH2-CH2-CH2-CH2-NH2.HCl

So you must have a trimming effect/buffer effect for both pKa's of the diaminobutane...
==> The second one should be (I don't have the precise value but it must be 3 to 4 pKa units lower than the first one) arround 6 (+/-1 that is pH 5-7);
==> The first one should be arround 10,8 (+/-1 thus pH 11,8-9,8... what you observed)

Note that pH-meters/ metry is usually done into water alone... into a mix of water/ethanol or ethanol alone the measures may provide strange readings.

NaOH is quite soluble into ethanol...
I suspect your procedure calls for addition of saturated NaOH/ethanol solution to a saturated diaminobutane dihydrochloride/ethanol; in principle when stoechiometric amounts are used, one should get the free base in solution into ethanol and a precipitate of solid NaCl (plus a little water formed into the neutralization process).

***********
To me it would be best (although stinky... putrescine smell like dead meat/zombie (just like cadaverine (diaminopentane; hence their special alchemist names):
Do this into an expandable recipient/reactor (NaOH will ruin any glassware upon heating; the glass will be corroded and become opaque/white); the distillation device must be hermetically closeable (except if you wish to get all dead meat eater arround and smell like the morgue/mortuary.
1°) Add DAB (diaminobutane) dihydrochloride to warm water (about 1g/10 ml)
2°) Add excess saturated NaOH/H2O solution and mix the two (it should warm up a little since it is a neutralization and this produces a lot of heat tempered a little by the initial water
3°) Distil... only DAB and water will pass over (no need of a multiple step/plate distillator... only one plate (a tube) is sufficient (like an alchemistry horn / retort)... water, NaOH and NaCl will remain into the initial flask (aside with Na silicate from dissolving the glassware).

Enjoy ;)


[Edited on 19-9-2017 by PHILOU Zrealone]


Very good, thank you. I will try your suggestions.

The problem with pH hitting a wall was just NaOH and water - no diaminobutane. Is there a method to create the 'excess saturated NaOH solution'? A specific formula?

I am somewhat familiar with distilation apparatus, but not with a closed or 'hermetically' sealed type. How is this made, or what is it called? I am most curious how it copes with changing volume of distillation.

EDIT: Is the sealed distillation just as simple as this? I would expect it to develop pressure if the erlenmeyer and all junctions were airtight, no?


image001.jpg - 120kB

Would not #9 need to lead to some type of expansion chamber capable of expanding to meet the changing volume? If so, what is suitable as an expansion chamber for this purpose?







[Edited on 19-9-2017 by Freddyhampt]
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[*] posted on 19-9-2017 at 10:40


Have number nine lead to a trap with some acid in it, to catch any zombie juice trying to escape. And put crushed ice and salt into 16, to keep it from evaporating.



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[*] posted on 19-9-2017 at 12:52


@Freddyhampt,

You got it :D

It can be hermetical if you have a cold trap as the end recipient; then no pressure build up can occure (assuming you have enough cooling fluid)... with an efficient cooling the all system can't display any overpressure since any vapour forming is condensing into the cold trap... the pressure into the system remains thus close to constant.

Exces means what it means...
==> over the stoechiometric amount...
If you know how much DBA dihydrochloride you put into your reactor in grams; then you know the number of moles of DBADHC and because of the 1/2 ratio for neutralization (1 DBA.2HCl needs 2 NaOH); then you find by conventional stoechiometric calculations how much g of NaOH you would need... any quantity above this is exces... since NaOH is the cheap reactant... you can work on a 1,5 to 2 fold exces.

[Edited on 19-9-2017 by PHILOU Zrealone]




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[*] posted on 19-9-2017 at 13:04


Quote: Originally posted by DraconicAcid  
Have number nine lead to a trap with some acid in it, to catch any zombie juice trying to escape. And put crushed ice and salt into 16, to keep it from evaporating.


Thank you, will do!
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[*] posted on 19-9-2017 at 13:05


Quote: Originally posted by PHILOU Zrealone  
@Freddyhampt,

You got it :D

It can be hermetical if you have a cold trap as the end recipient; then no pressure build up can occure (assuming you have enough cooling fluid)... with an efficient cooling the all system can't display any overpressure since any vapour forming is condensing into the cold trap... the pressure into the system remains thus close to constant.

Exces means what it means...
==> over the stoechiometric amount...
If you know how much DBA dihydrochloride you put into your reactor in grams; then you know the number of moles of DBADHC and because of the 1/2 ratio for neutralization (1 DBA.2HCl needs 2 NaOH); then you find by conventional stoechiometric calculations how much g of NaOH you would need... any quantity above this is exces... since NaOH is the cheap reactant... you can work on a 1,5 to 2 fold exces.

[Edited on 19-9-2017 by PHILOU Zrealone]


Excellent! Again, thank you. Will report findings.
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[*] posted on 26-9-2017 at 07:04


I did not perform distillation because it appears I did not remove the DHC (dihydrochloride). To a solution of DABDHC (diaminobutane dihydrochloride aka putrescine dihydrochloride) I very slowly added a solution of NaOH. I did this dropwise while stirring and checking pH frequently. At no point did I get the odor of DAB. I took pH from 7 to 13 using test strips. Because I never acheived the odor I did not attempt distillation.

The NaOH is to liberate the dihydrochloride from the putrescine, correct? Distillation is merely to concentrate the final product and has nothing to do with the salt removal and conversion to putrescine, correct? My understanding is that the odor should be present once the DHC is liberated from the DAB. Am I mistaken in any of this?

Please, any suggestions?

[Edited on 27-9-2017 by Freddyhampt]
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[*] posted on 27-9-2017 at 03:57


The distillation step allows you to leave the salt behind because non volatile.

If your reactants were cold enough... the volatility is less... so should the smell... mild heating should reveal if free DAB base is present or not.

If the pH changed from 7 to 13 then your NaOH is efficient and still active; so you should have smell at ambiant temperature, unless very dilluted solution or if the DABDHC is not DABDHC but something else?

Edit:
Last option... you are imune to the smell of putrescine and cadaverine... I think it is possible that a genetical modification of the smell receptors may induce such effect... rare but possible...
==> Ask other people to smell ;o)

[Edited on 27-9-2017 by PHILOU Zrealone]




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[*] posted on 27-9-2017 at 15:37


Quote: Originally posted by PHILOU Zrealone  
The distillation step allows you to leave the salt behind because non volatile.

If your reactants were cold enough... the volatility is less... so should the smell... mild heating should reveal if free DAB base is present or not.

If the pH changed from 7 to 13 then your NaOH is efficient and still active; so you should have smell at ambiant temperature, unless very dilluted solution or if the DABDHC is not DABDHC but something else?

Edit:
Last option... you are imune to the smell of putrescine and cadaverine... I think it is possible that a genetical modification of the smell receptors may induce such effect... rare but possible...
==> Ask other people to smell ;o)

[Edited on 27-9-2017 by PHILOU Zrealone]



Okay thank you. Will try this and report back the results.
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[*] posted on 10-10-2017 at 23:39


Quote: Originally posted by Freddyhampt  
Okay thank you. Will try this and report back the results.

Are you sure that you have what you think you have? Where did you get it? What you did is essentially a test for this compound, and if it actually existed in significant quantities, you'd DEFINITELY be aware of it by now.




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[*] posted on 13-10-2017 at 17:38


Quote: Originally posted by Melgar  
Quote: Originally posted by Freddyhampt  
Okay thank you. Will try this and report back the results.

Are you sure that you have what you think you have? Where did you get it? What you did is essentially a test for this compound, and if it actually existed in significant quantities, you'd DEFINITELY be aware of it by now.


A chemical supplier. It has a definite semen smell. It is a yellowish crystalline powder. It is putrescine dihydrochloride, not putrescine.

[Edited on 14-10-2017 by Freddyhampt]
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[*] posted on 16-10-2017 at 14:08


Try adding a small amount to a hot saturated solution of sodium or potassium carbonate, perhaps? There should be be CO2 bubbles visible, and a strong smell accompanying it. Failing that, try adding it to a saturated solution of NaOH or KOH in hot methanol or ethanol that contains about 25% water by volume. Test-tube quantities are sufficient. These are just wild guesses, though.

You really should test the melting point and compare it to literature, just to be certain.




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[*] posted on 16-10-2017 at 18:04


Thank you for the ideas.

I will test the melting point with capilary tube in oil. Melt point is specified as just under 300 deg C. Should I use silicone oil, or another bath oil?


Also, to acheive a saturated solution what is the approx ratio (by mass or volume, mg : ml)?....
Na2CO3 : water
NaOH : ethanol
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