1- Set up your email account on outlook using POP3
2- Then drag and drop the folders from IMAP account in outlook to POP3 account.
Please notice that after this step all the folders will disappear from IMAP and from your webmail, and will only exist on your POP3 account.
3- In order to move the emails from sent folder on (IMAP) to sent Items on (POP3):
a- Open the sent folder on IMAP outlook account.
b- Select all emails.
c- drag and drop them to the sent items on POP3.
4- After dropping all your folders to POP3 account, Delete your IMAP account.