video tutorial Citrazinic acid from citric acid and urea

Name: video tutorial - Citrazinic acid from citric acid and urea
Uploaded: 2025-12-11T09:03:44.085Z
Duration: 5 min 28 s
Description: We will be making citrazenic acid. The yields are not so good but the raw materials are very cheap and easy to come by....Start off with 75 grams of citric acid. Our citric acid claimed to be pure acid but was in fact the monohydrate so try to find out what it is you have.

Objective: synthesize citrazenic acid;低 yields but raw materials are cheap and readily available.
Starting materials: 75 g citric acid (likely monohydrate), 60 g urea; urea is OTC in some cold packs; other salts (e.g., ammonium chloride) can be used.
Procedure (condensed): grind and mix urea with citric acid, heat to about 70°C until liquefaction and ammonia evolution (above 130°C); color deepens to caramel; after about 50 minutes at ~150°C a thick syrup forms; cooling yields a glassy solid; dissolve in 150 mL boiling water; solution turns dark brown-yellow; adjust pH from ~6 to 9 with NaOH to form soluble salts; filter slowly; acidify with concentrated HCl to precipitate the product as a free acid (orange-yellow precipitate after ~20 mL HCl); filter and dry; wash with ice-cold water.
Purification steps: optionally dry the solid in a desiccator (unclear necessity); wash with 30 mL NaOH, then 30 mL methanol, chill to reduce solubility; filter to remove darker color; wash with 10 mL cold methanol and 20 mL dichloromethane; dry under vacuum.
Product and yield: golden yellow fine powder; ambiguity whether free acid or amide; obtained 7.73 g from 75 g citric acid (~14% yield); recrystallization attempts failed due to lack of suitable solvent; used as is for further experiments.