Not that I’ve looked, but I don’t remember reading this rationale for the Obama administration’s efforts to incentivize Syria to accede to the CWC, etc.. Essentially, Derek Chollet told the New Yorker last month that the US needed to prevent ISIS from seizing the weapons and thereby creating the need for a military invasion:
The operation to remove chemical arms from Syria concluded in the summer of 2014, just as isis swept in from the desert. Had those weapons remained, the U.S. might well have felt compelled to send a huge force to seize them. “Obama would have invaded Syria,” Chollet said. “We could not have allowed even the smallest chance that isis could have gotten hold of them.” Instead, Obama dispatched some seven thousand American troops to northeast Syria and to Iraq in order to fight isis. After they arrived, a de-facto no-fly zone was established in Kurdish-controlled northeast Syria. The policy, which remains in effect, has kept Assad and his allies from bombing civilians in the area.