Huge 301 Redirect list breaks .htaccess file

So I’m working on this site for a woman who recently decided to delete a ton of her older posts because she was going a new direction with her blog.

She talked with an SEO expert who pulled a list of fourteen thousand 404 errors from Google Analytics, and we decided the best course of action was to 301 redirect them all to the homepage. Because there were 1400 of them.

So… I’ve never really done this before, so what I tried was to do a series of importing the list to excel, copying it into plain text and doing find replacing until every single link was in this format:

Redirect 301 /old-link http://newurl.com

HUGE list. Just massive. I’ll attach the file in comments.

Of course it breaks the site. Can someone please advice what on earth I should do?