Comment · Fri, February 14, 2014
Issue with Caffeine HCL Solution
Original post in this thread
MisterYouAreSoDumb · 7 points
I am not a chemist by any means, so I am a little unclear about a couple things. I am trying to make a solution of caffeine HCL by doing an acid/base reaction with anhydrous caffeine and hydrochloric acid. I am doing this to increase the solubility of caffeine in water, as this is really the only way to get it in the concentrations I need.
So I slowly add 24 grams of caffeine to 30ml of 38% hydrochloric acid. Then I add water till the solution reaches a total volume of 120ml. At that point, it clears up and forms a perfect solution with no caffeine left suspended. I checked the pH of the solution, and it is neutral at 7. At this point I figure it worked properly, since the pH is neutral. However, the solution is super sour/acidic in taste. I double checked my pH test strips in pure water and a solution of citric acid and water, and they seem to be fine. The pure water gives the same reading as my caffeine HCL solution.
So a couple questions. First, is a solution of caffeine HCL going to be stable at room temperature, and be safe to consume? Two, why is it sour if the pH is neutral?
What they were answering
Borax · 4 points
I checked the pH of the solution, and it is neutral at 7.
Something has gone wrong here, but there is no WAY 24g of anything other than NaOH or a similar strong base will neutralise that much conc. HCl.
Use half or a quarter of that amount of HCl.
Not sure what's wrong with your pH strips but they're not working.
u/MisterYouAreSoDumb
That's exactly what I was thinking. That is why I tried to test the strips with other neutral and acidic solutions to see how they reacted. I was dumbfounded when the pure water result showed the same pH as the caffeine HCL solution. What do you think is up with that?
I thought it was weird that a weak base was neutralizing a strong acid in those ratios.