The active ingredient of the accelerator is usually some kind of tertiary amine. The amine attacks the double bond in the cyanoacrylate molecule that then initiates the polymerization of the surrounding molecules. Water will also initiate the polymerization but not as effectively as the amines and is why we use CA glues to glue up wood since wood always has some water in it. Almost any amine or base will act to initiate these reactions but because many of the amines have unpleasant smells the ones they use have higher molecular weights so they don't stink as much. My experience is that most of the accelerators use either methanol or ethanol as a solvent.
I don't know how long CA glue is good for but we used some for a demonstration that was at least a year old (maybe two) and it was very brittle and the turnings kept flying off the lathe. Fresh CA didn't have the same problem. I also know that refrigerating a bottle will preserve it longer than if it is sitting on the bench.
Can you guess who was trained as a chemist?
Cheers,
David