Ammonium Picrate Recipe

Ammonium Picrate Recipe

by fellow_researcher

<ol> <li>2,4,6-Trinitrophenol ammonium salt is formed when the ammonium ion, NH4+, attaches itself to the phenol group, OH, of picric acid. <li>I suppose the H from OH is stripped away making O- that balances the positive ammonium ion. <li>To make, dissolve picric acid in excess ammonium hydroxide. <li>Add 1 g of picric acid to a 250-mL beaker then add 100 ml of hot concentrated ammonium hydroxide. <li>Once the picric acid has dissolved, some will precipitate out of solution upon cooling. <li>The liquid must be evaporated to fully precipitate the crystals. <li>Evaporation can be accelerated by heating the solution on a hotplate or in a heated pan of water. <li>More ammonium picrate can be prepared at once by using the same 1:100 ratio of grams picric acid to milliliters ammonium hydroxide. <li>You will need a graduated cylinder to measure the liquid. <li>The pure substance occurs in two forms, a stable form which is bright yellow and a less stable form which is bright red. <li>The crystals, which separate here, are the red form. <li>The yellow form can be procured by recrystallizing the red several times from water. <li>The red form will eventually change into the yellow form if stored as a concentrated solution. <li>Keep this material as dry as possible. </ol>