The answer is yes you can have 2 separate circuits in the same box (they can have a splice also but not needed in your case). The only concern would be the total box fill. 0 for each conductor for 14 gauge wire and 2. This approach can save space and simplify your electrical layout, making it a practical choice for various settings. There are ways to split a receptacle so that the top and bottom sockets are on separate circuits, it used to be a thing where one was tied to a switch and the other was constant, so you can plug in a lamp to the switched socket and turn it on / off via the wall switch (and if you have a mystery. I have a box with a double outlet on one circuit and a light switch on a separate circuit (both 15 amps), all within the same box - is this permissible? Owner of independent electrical contracting company.