DIY Kitty Crack: ultra-potent catnip extract

Step 13 Optional sodium bicarbonate wash

This step is optional but it's easy and will further increase the purity of your nepetalactone. When you steam distill catnip, one of the side reactions is that some of the nepetalactone gets hydrolyzed to nepetalic acid. Nepetalic acid is not harmful, but it has no effect on cats so it's considered an impurity. Separating it out is a piece of cake, by virtue of the fact that it is an acid. When it reacts with a base, like sodium hydroxide or sodium bicarbonate (baking soda) it turns into its sodium salt, which is water soluble. So all you have to do is wash your toluene extract with a solution of baking soda in water and the desired nepetalactone will be left behind in the toluene layer. See the third picture below for a schematic of what's going on.

Prepare a base solution by dissolving 1 tbsp of baking soda in 1 cup of water. Add a volume of this approximately equal to the amount of toluene you have. Stir it or shake it up really well for a minute, then allow the layers to separate. Use the eye dropper to remove the bottom water layer, which contains the impurities. Repeat the wash with a fresh portion of base-water and again remove the bottom layer.

The toluene solution that you're left with after this washing sequence now has a little bit of water in it, so we'll need to clarify it again, as in steps 11 and 12.

Comments

[Ugifer]

Great method and a very fine instructable.

Just wondering whether you could omit this step by including some base in the initial salt-out. I guess the nepetalate salt might emulsify the mixture a bit more but it would save the extra step and the losses in washing & drying again if you could avoid the separate washing step.

Just a thought.