The punctuation of Reunion movies is different, and the time points of Reunion 1/2 and Iron Man 1/2 are very different. It can be said that it happened at the same time, but the development story is different, the order is different, and the film release date is different. Therefore, according to the release time of the film, it cannot be considered as the existence time of the character. After all, in many famous movies, there are some.
Iron Man 3 and previous versions of the reactor can be said to be built-in, that is, installed in your chest, not only to provide energy for armor, but also to maintain life. However, in the movie "Reunion" series, you were asked to use an external reactor inserted in armor, just as Tony's black brother installed an external reactor in the war machine just to provide energy for armor. And when attacking the Hydra base, Tony didn't see the reactor on his chest when he left the armor in the sentry mode of armor, but the armor had energy activities!
Iron man had an operation. In Iron Man's last movie, Stark had an operation in China and took out shrapnel. Stark no longer uses the Ark reactor for energy supply and life extension, but the reactor on the new spacesuit only exists on the spacesuit, not on Stark. This can be seen from Stark's coming out of the steel suit.
However, The Avengers 1 didn't tell the story of Iron Man 3, and it didn't operate at that time, so the upgraded palladium element reactor was used, but it didn't exist in The Avengers 2.