Reducing sodium benzoate

[willowchar]

Can anyone recommend an easy way to mill sodium benzoate. I find it quickly becomes "sticky" shortly into the milling process even after pre drying it in an oven for a couple of hours . It is also nearly impossible to screen as it clogs up screens. I have access to some stock that is the size of rice grains that I would like to powderize.

Thanks in advance.

[justvisiting]

Some folks have had good luck freezing the jar full of media and benzoate, and then running the mill in a freezer. I would let it warm back up to room temp before opening it though, or you might get condensation on the cold surfaces.

[NeighborJ]

Two words: blade mill

[justvisiting]

Actually, NeighborJ's way might be better. A while back, I found out that ball milling sulfur prills was nowhere near as effective as blade-milling. The blade mill did more in a few seconds than an hour of ball milling. Maybe it works the same with sodium benzoate.

[willowchar]

Thanks for the feed back. Ill try the blade mill and post the results.

Cheers!

[NeighborJ]

The key to using the blade mill is to only fill the jar to 25% volume. Too much and the powder overheats before all the clumps are reduced.

[a_bab]

The *real* key is ethanol.
Soak the granules in rubbing alcohol and see what I mean: you can smear them on your fingers into a very fine dust.

So you have to come up with some wet milling process; a blender does wonders.

If you are at it, add the catalyst in the correct proportion; it will help when the alcohol dries up to avoid clumping.

Edited November 16, 2020 by a_bab

[willowchar]

Thanks for the extra info neighborJ on the blade mill loading capacity recommendations.

For the ethanol route a_bab, what would you recommend the ratio of benny to alcohol be to avoid clumping?

[willowchar]

Could one just use water as the solvent then evaporate and dry in stead of alcohol?

[NeighborJ]

I've done experiments using (hot) saturated solutions of potassium benzoate or sodium salicylate added to perchlorate using water. The solution absolutely required heating to 100C and the benzoate or sali would drop out as extremely fine, well incorporated particles if it was cooled quickly enough. The fuel needs removed from heat before the perc is added then quickly stirred. Makes some wicked whistle fuel. Never tried sodium benzoate with this method. One thing needs mentioned:do not use a copper pan, benzoates, salicylates, pthalates all dissociates in solution and quickly attacks copper.

Was it worth the effort? Meh, it took a day to completely dry and left whistle caked in a pan.It made good fuel every time. It would all depend on how patient you are.

[willowchar]

Turns out neighborJ's method of using a blade mill was spot on. The blade mill method was the most convenient and was more effective than using a ball mill or coffee grinder. Thoroughly drying the sodium benzoate and 25% loading are definitely key.

Thanks to everyone for all the advise:)