Should I submit a conference paper (extended abstract) to this chemical engineering conference?
As a chemical engineer, I would recommend against submitting an extended abstract. The primary reason for this is that, unlike proceedings of the Materials Research Society, the extended abstracts of the AIChE annual meeting are not peer-reviewed. Therefore, any such publication will automatically be of lower weight than something that has been published in a venue that provides peer review.

In addition, because the work has effectively been "published," you will find it harder to secure publication for fuller versions of this work later on, as many journals could view the extended abstract as a "prior publication" and reject a paper on those grounds. 

Moreover, as David Ketcheson suggests in his answer, the dissemination of your research will be greatly hampered by the relatively low circulation of the extended abstracts. 

So, for this conference in particular, and more generally for any conference whose proceedings are not peer-reviewed, I would avoid submitting extended abstracts and conference proceedings.