| 摘要 |
<p>A process for producing a polyester which comprises reacting a ketene with crotonaldehyde having a purity of 95 wt.% or higher. The unreacted crotonaldehyde remaining in the resultant reaction mixture may be recovered from the mixture and recycled to the reaction system. The crotonaldehyde to be fed to the system has an α-vinylcrotonaldehyde content of, e.g., below 0.5 wt.%, and a paraldehyde content of, e.g., below 5 wt.%. The polyester obtained by the process is decomposed with, for example, hydrochloric acid to efficiently obtain sorbic acid having an excellent hue.</p> |
