Is there any difference between particularly and in particular?
When should I use each one of them?
"In particular" can be used as a sentential adverb, in the same way that "yesterday" can be.
Particularly can usually be used as a sentential adverb (but "in particular" often sounds better in these situations):
On the other hand, particularly is used to modify an adjective (or adverb) directly, and "in particular" cannot do this. Compare: