I have a video file that I want to split the audio form it and create a separate audio file. Is this is possible with KDEnlive? Thanks for the help.

Yes you can. In the Render dialogue, open the Destinations drop down menu and select Audio Only.

Depending on your Kdenlive version, you might also have an "Extract audio" entry in the context menu of the project tree that will create a wav file out of your clip audio

Thanks for the answer. that solves my problem.