The Catalan will do nothing.

Mainly because Spain has said that whilst it will not interfere in a referendum in another country and is neutral on the aspirations of the UK residents in the Scottish counties, it will however protect its interest regarding setting a precedent for EU entry of breakaways from existing EU states.

Although of course , Salmond reckons that with a mandate from Scottish voters, he can dictate to foreign leaders and for some reason, they have to listen! (See his comments re the pound.)