Dr. Bob helped me with this issue and sold me a large pressure equalized powder addition funnel, well worth the cost and for what it was a very
reasonable deal. I don't know if he has any more but for sensitive reactions that require intermittent powder addition they are awesome. I tried the
way of adding powder by connecting a flask buy a large diameter flex. tube I found the addition often became difficult to control as the reaction
progressed especially if the reaction was heated. The powder would become stuck together and as I said controlling addition when the powder is no
longer free flowing is like tossing acetic acid in a jar of baking soda, much more fun to watch than to clean up. |