Disable Emoji Text Replacement in OS X With a Simple Toggle
If you enter an old emoticon like 🙂 in OS X, many applications will automatically replace it with an emoticon. If you are not a fan of this behavior and prefer to use the old emoji, all you have to do is change the switch in the app.
For most text-entry applications, including messages, click Edit> Lookups. If you do not want the emoticon text to be replaced, make sure the checkbox next to the emoticons is unchecked. That’s all. From then on, this app will not replace these emoji with emoji.
How to Stop Automatically Replacing Emoticons with Emoticons in OS X | OS X Daily