Urea: Difference between revisions

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[[Category:NOWA]]
{{Compound|aka=diamino carbonyl|chemf=OC(NH2)2|sol_aq=≥1000|sol_et=50|mp=135|mm=60|density=1.32|pharm=yes|listed_who=yes|decomp={{DecompRow|temp=unk|input=urea|output={{#Chem:  NH3, CO2}}}}|industrial=yes|nowa=yes}}
{{Compound|aka=carbonyl diamine|chemf=OC(NH2)2|struct=Urea.png|sol_aq=≥1000|sol_et=50|mp=135|mm=60|density=1.32|medicine=yes|listed_who=yes|decomp={{DecompRow|temp=unk|input=urea|output={{#Chem:  NH3, CO2}}}}|industrial=yes}}
__TOC__
__TOC__
A major source of organic [[nitrogen]].
A major source of organic [[nitrogen]].
Line 29: Line 28:
# Until nothing but clear crystals remains
# Until nothing but clear crystals remains
The crystals are urea
The crystals are urea
=====further separation=====
<div style='margin-left:1em;'>
;Reactants
* [[Urine]]
* [[Calcium oxide]]
* [[Distilled water]]
* [[Ethanol]]
;Products
* [[Urea]]
* Mineral salts rich in [[Sodium chloride]] (roughly [[sea salt]])
* Organic sludge rich in phosphate and proteins
;Equipment
* Liquid Dryer/Evaporater
* Gas bubbling equipment
* (Optional) Distillation equipment
; Process
# Boil 10L of [[urine]] down to 1L (containing ~93g, 6.6M of [[urea]])
# Filter
# Residue contains organics, calcium and other phosphates, can be retained to produce phosphorus or burned and disposed
# Filtrate contains [[sodium chloride]] and [[urea]]
# Evaporate water by gentle heating (&le; 133&deg;C)
# Residue is mostly [[sodium chloride]] and [[urea]]
# Wash residue with hot concentrated [[ethanol]] several times, combine washings
#: '''NB:''' Urea dissolves easily, salt does not.
# IF (two layers form in the washings)
## Separate the aqueous layer and evaporate separately, producing mineral salts
# ENDIF
# Evaporate ethanol washings
#: '''NB:''' It may be worth condensing the ethanol vapors
# The residue is urea. It should crystallize
</div>


=====via oxalic acid=====
=====via oxalic acid=====
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# Until no further residue is collected and the crystals are as pure as desired
# Until no further residue is collected and the crystals are as pure as desired
===Synthesis===
===Synthesis===
====industial====
* Combine [[carbon dioxide]] with [[ammonia]] <ref>{{Cite patent|4061675A}}</ref>
*: {{#Chem: CO2 + 2NH3 = CO(NH2)2 + H2O}}
====Wohler====
====Wohler====
* Combine '''silver cyanate''' with [[ammonium chloride]].
* Combine '''silver cyanate''' with [[ammonium chloride]].
*: {{#Chem: AgNCO + NH4Cl → CO(NH2)2 + AgCl}}
*: {{#Chem: AgNCO + NH4Cl → CO(NH2)2 + AgCl}}
==See Also==
==See Also==
* [[urease]]
* [[urease]]

Latest revision as of 20:32, 20 October 2023

 
Urea
aka diamino carbonyl
Urea struct.png
Chemical formula OC(NH2)2
Molar Mass(g/mol) 60 
Density(g/cc) 1.32 
Melting Point(°C) 135 
Solubility in water(g/L) ≥1000 
Solubility in ethanol(g/L) 50
NFPA 704
NFPA704.png
0
0
0
 

 

Thermal Decomposition
urea
unk°C
NH3,CO2

A major source of organic nitrogen.

Uses

Primary

  • Industrial chemical
  • Fertilizer (46-0-0)

Secondary

  • Feedstock (through natural decomposition) to ammonia
  • Feedstock for urea nitrate for cold packs
  • Pharm: (ointment) Skin treatment

Natural occurrence

  • Appears naturally in urine and to a lesser degree in compost

Hazards

Production

Extraction

from urine

Approximately 9.3g are expected in a liter of fresh human urine. Delay in processing allows bacteria to convert the urea to ammonia.

simple evaporation
  1. Dry urine to solids
  2. Repeat
    1. Dissolve in ethanol
    2. filter
    3. discard residue
    4. evaporate alcohol
    5. gather crystals
  3. Until nothing but clear crystals remains

The crystals are urea

further separation
Reactants
Products
Equipment
  • Liquid Dryer/Evaporater
  • Gas bubbling equipment
  • (Optional) Distillation equipment
Process
  1. Boil 10L of urine down to 1L (containing ~93g, 6.6M of urea)
  2. Filter
  3. Residue contains organics, calcium and other phosphates, can be retained to produce phosphorus or burned and disposed
  4. Filtrate contains sodium chloride and urea
  5. Evaporate water by gentle heating (≤ 133°C)
  6. Residue is mostly sodium chloride and urea
  7. Wash residue with hot concentrated ethanol several times, combine washings
    NB: Urea dissolves easily, salt does not.
  8. IF (two layers form in the washings)
    1. Separate the aqueous layer and evaporate separately, producing mineral salts
  9. ENDIF
  10. Evaporate ethanol washings
    NB: It may be worth condensing the ethanol vapors
  11. The residue is urea. It should crystallize
via oxalic acid
  • Precipitate from urine using oxalic acid, then extract again using calcium hydroxide. Detoxify the calcium oxalate by thermal decomposition.
    CO(NH2)2 + H2(COO)2 → C3H6N2O5
    C3H6N2O5 + Ca(OH)2 → CO(NH2)2 + Ca(COO)2 + 2 H2O
    Ca(COO)2
    {
    →
    ≥600°C}
    CaCO3 + CO
via nitric acid
  1. Combine urine and nitric acid, producing urea nitrate crystals
  2. Filter
  3. Discard filtrate
  4. Repeat
    1. Prepare a saturated solution of urea nitrate in boiling water
    2. Mix in charcoal fines
    3. Stir
    4. Cool
    5. Filter through charcoal
    6. Discard residue
    7. Dry solution to crystals
  5. Until no further residue is collected and the crystals are as pure as desired

Synthesis

industial

Wohler

See Also

References

  1. ↑ US patent 4061675A
    Link courtesy Google
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