as as

English as a Second Language English Vocabulary, Grammar and Idioms
1
  1. I would like to use the word as as a preposition.
  2. I would like to use the word as a preposition.
    Are they correct?
    Do they mean the same?
2

Your sentence should be punctuated in a way that indicates the first ‘as’ is separate:
I would like to use the word ‘as’ as a preposition.

The second sentence does not mean the same.
I would like to use the word as a preposition. - here the word that you wish to use is not stated. It will have been made clear prior to this what that word is.