An unsuccessful search for methyl ketene (CH₃CHCO) was reported in 2018 by Bermúdez at al. Using a newly measured rotational spectrum, the molecule was sought in line lists of a number of the most prolific interstellar molecule factories: Orion KL, Sgr B2, TMC-1, and Barnard 1 (B1-b). No lines could be assigned to methyl ketene. Methyl ketene is the second most stable isomer of C₃H₄O compounds. The most stable isomer, propenal (CH₂CHCHO), was detected in 2004. Ketene was discovered in the late 1970s.

Methyl ketene or 1-propen-1-one, is stable enough that a number of its properties have been measured, including its infrared spectrum. It does not appear to be widely used in terrestrial chemistry.