In this repository there is a file (Macro.txt) that when used in vba it lets you select a word document, choose a page to start extracting information, choose a number of pages to extract, turn those pages into pdf, repeat. When you extracted all the pages you needed, write 0 to stop the loop.
I did this code as I couldn't find myself a solution on the web, so I hope other people that have the same problem, can use it without problems.