Both are useful, but have their advantages/disadvantages. Chemistry is learning different chemical interactions on a molecular level, and is experimental. You learn chemistry really good, but you only know how to theoretically make stuff in the lab (lab scale). Chemical engineering is more the implementation of already existent chemical processes and scaling them up and optimizing the processes. It also has an economic note to it, as you need to efficiently choose the best equipment for the given process/economic availability of such. As in the contents of the degree, as the name implies, in chemistry you only learn different chemistries, with some exceptions of course. chemical engineering degree consists of 70% physics (engineering) classes such as heat and mass transfer, fluid mechanics etc. but still learn enough chemistry to understand most chemical principles and reactions given. So in conclusion I would say if you are more interested in developing new RC-s, I would suggest chemistry, but if you want to produce existing RC-s and scaling them to industrial scales, ChemE degree will be more useful. More so that you already have a broad understanding of the industry and processes as a whole.
