Yes he does have the authority to adjourn congress.
If they do not agree to come into session, or agree to adjourn, he may do so and run the country under existing laws afforded to him.
It has never been done before, but it is high time it is done now since the scum bitch from the Frisco area is playing her little cute games.
Yeah, and also the jackass from Kentucky. Mitch always puts the Senate into a pro forma session specifically to prevent recess appointments. A lot of this bull crap plays right at the feet of Republicans