Industrial propylene hydroformylation (PHF) to produce butyraldehyde uses polymer-grade propylene (99.99 wt% purity) obtained from propane dehydrogenation (PDH) followed by separation of the propylene/propane mixture by distillation. Recently, it was shown that the effluent from a PDH reactor (60–70% propylene in propane) can be directly used for PHF over Rh-based complexes, eliminating the energy intensive C3 distillation step. Because only propylene reacts in the PHF reactor, an enriched propane stream results and is recycled back to the PDH reactor. At industrial conditions (2.5 MPa, 90°C), hydroformylation with mixed propylene/propane feedstock occurs in a propane-expanded liquid (PXL) phase. The capital investment for the PXL process is approximately 20% lower than the conventional process. The production cost in the PXL process is also lower, resulting in an annual savings of nearly $12M for a 300 kt/y plant. Comparative gate-to-gate environmental impact analyses shows that the PXL process results in reduced environmental impacts (greenhouse gas emission by 20%, air pollutants emission by 22% and toxic release by 21%) compared to the conventional process.