Guy
For the MAX232, I think any capacitor of the correct value and voltage rating will be OK.
However, for other circuits, paricularly those with high frequencies, the construction of the capacitor becomes critical.
Some capacitors have inductance due to the wires connecting them to the circuit and the way they are made, they are rolled up like toilet paper! :lol:
These types are very poor at high frquencies.
What is a "high frequency"?
We could argue about this for pages on here, but I am going to say anything above 50kHz is high for the purpose of this discussion.
JimB