0.1 M Tetrabutylammonium Hydroxide Solution Preparation and Standardization

Preparation and Standardization of 0.1 M Tetrabutylammonium Hydroxide (C16H37NO) Solution in Pharmaceutical Labs.

Name: 0.1 M Tetrabutylammonium Hydroxide (C16H37NO)

Reagents :

• Tetrabutylammonium iodide
• Methanol
• Dimethylformamide
• Thymol Blue
• Benzoic Acid

Preparation of 0.1 M Tetrabutylammonium Hydroxide:

• Mix 40 grams of Tetrabutylammonium iodide in 90 ml of dry methanol. Then, put in 20 grams of finely powdered Silver Oxide and shake hard for an hour.
• Take a bit of the mix, spin it fast, and test the liquid on top for iodides. If it shows positive, add another 2 grams of silver oxide and shake for 30 minutes. Do this until there are no more iodides.
• Then, strain the mix through a fine filter and wash the container, and filter with three 50 ml amounts of toluene.
• Mix the washings with the strained and add more Toluene to make it 1000 ml.
• Blow dry, carbon dioxide-free nitrogen into the mix for 5 minutes.

Method of Standardization:

• Mix 10 ml of Dimethylformamide with 0.05 ml of a 0.3% solution of Thymol Blue in Methanol. Slowly add Tetrabutylammonium hydroxide solution until you get a clear blue color.
• Now add 0.2 grams of Benzoic acid, stir till it dissolves, and add more Tetrabutylammonium hydroxide solution until the clear blue color comes back.
• Make sure the mix doesn’t touch air throughout this check. The amount of solution used in the second round tells you how much tetrabutylammonium hydroxide you’ve got.
• Remember, each ml of 0.1 M tetrabutylammonium hydroxide equals 12.21 milligrams of C7H6O2.

Storage:

Store below 25°C & store in an amber-colored bottle. Protect exposure from CO₂ & water.

Shelf life:

The shelf life of the above solution shall be one month from the date of preparation. Restandaridize the above solution daily before use.

Calculation:

REFERENCE: Indian Pharmacopoeia