Sciencemadness Discussion Board

Urea Storage

Aqua_Fortis_100% - 15-10-2011 at 00:16

Hi

2 years ago I tried to purify some farm grade urea (contaminated with a few KCl grains and some dirty shit) by dissolving the urea in warm water, filtered and boiled almost all water (some of the ammonia evaporated) then let it crystallysed, squeezed tight the mass of crystals using a clean piece of cloth (cooled the solution to obtain more urea crystals) and repeated all this process more 3 times trying to remove urea tan colour.. Since I think all of this process liberated a lot of ammonia, my product could not be pure urea, but a mix of urea and some cyanuric acid, mellamine, and related compounds...



Today I bought 2 Kg of the very same impure farm grade of urea and Im thinking in store it as solution of know molar/% strenght.. Dissolving the material in water, filtering to remove insoluble material, treat it with some activated charcoal, filter and bottle/lable it in a dark glass container.


Does urea hydrolyze in solution during storage at room temperature?

If this not possible or the degree of hydrolysis is negligible then it would be interesting to me. Unlike previous "purified" material, I will have urea with less organic contaminants, but in other hand I will have more K,Na, chloride, sulfate, etc contaminants..

But that doenst matter, since I will use that solution to generate ammonia (or then chlorinate to get chlorourea then hydrazine)..

Dry ammonia can be made in direct form heating a mix of ammonium chloride and urea with isocyanuric acid as byproduct..

http://www.youtube.com/watch?v=wlnc0tqRkFk

The video above was when I made some cyanuric acid.


Another thing I would like to ask, does reacting urea solution with NaOH and heating produce pure ammonia (without CO2 or other gaseous products), i.e., will work the reactions bellow?

(NH2)2CO + 2 NaOH --aq--> Na2CO3 + 2 NH3
(NH2)2CO + Ca(OH)2 ---aq---> CaCO3 + 2 NH3


Thanks


[Edited on 15-10-2011 by Aqua_Fortis_100%]

bbartlog - 15-10-2011 at 04:28

Quote:
Does urea hydrolyze in solution during storage at room temperature?


I suspect it would. Urine does. Granted there is a lot of other stuff in urine, but the hydrolysis is self-catalyzing since the solution becomes more basic as the urea decomposes into ammonium carbonate.

Magpie - 15-10-2011 at 07:54

I have found that this method of not_important works well:
Quote: Originally posted by not_important  
Crack the prills open, Just crush them some, you don't need to take them to a powder. Extract with near boiling alcohol, filter, cool, and filter to collect the urea. Use the filterate to extract more of the fertilizer.

One gram of urea dissolves in
1 ml H2O
10 ml 95% ethanol
1 ml 95% ethanol boiling
20 ml absolute EtOH
6 ml MeOH

When hot urea slowly reacts with water and alcohols, so try to do the hot stage as quickly as possible. The roughly 10:1 solubility swing gives pretty good recovery.


You don't need pure ethanol. Just use the denatured alcohol available at hardware stores. Good luck.

Aqua_Fortis_100% - 15-10-2011 at 22:28

Thanks bbartlog, Magpie and not_important too.

Took some pictures of my products..

The first I mentioned (recrystallized) which was lying around until today:





Nearly 2 Kg farm grade urea recently acquired:



Some hundred grams of it were dissolved in my ~2 month urine samples (~5L in total), along with a pinch of ammonium sulfate.. After this pic, my first 'ultrapure' recrystallized urea was too all added to urine samples.
[from left to right, the third bottle contains agricultural grade (iron contamined) ammonium sulfate]

bbartlog, I hope the urea does not degrade (only to nitrate, of course :cool:) before addition to nitre-bed..




I will be making some nitre beds with it.. Thinking one (stupid) way is almost like growing your own OXIDIZING mushrooms, but with bacteria kkkkkkk

Im not expecting great yeilds, I may dillute the solution a bit (or not) and pulverize it constantly on very porous and constantly aerated bacteria/lime-containing soil couple of weeks or even months.. Then leach this to obtain calcium nitrate which is converted to KNO3 by K2CO3..

The urea below was purchased today along with a 220°C thermometer in a essence/soap shop. Appear to me as good thing.. :D





[Edited on 16-10-2011 by Aqua_Fortis_100%]

bbartlog - 16-10-2011 at 05:16

The degradation/hydrolysis would not matter if you are adding it to a nitre bed. If you have months-old urine in bottles, the urea there has most likely already been transformed into ammonia or ammonia compounds. But that's OK (desirable even), the nitrifying bacteria act on ammonia.
I also think purification via recrystallization is pretty quixotic given your aim. Your feedstock is going to get mixed with dirt... why clean it beforehand?

Aqua_Fortis_100% - 16-10-2011 at 10:23

No, I wont purify this, since pure urea is somewhat more expensive but still very OTC..
This agricultural urea (in PET bottle) wont be used in nitre-beds (only some of it was dissolved in urine)... I will use it to generate ammonia gas..

The thing is that recrystallizing/cleaning urea before reaction with base would give me purer byproducts (Na2CO3, CaCO3, etc) which could be further purified and used in other projects.