Why does liquid maleic anhydride turn yellow?
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The liquid maleic anhydride didn’t appear yellow when sampled; the sample was left there, and then suddenly it turned yellow – what’s going on? Furthermore, liquid maleic anhydride should theoretically crystallize into a solid state at room temperature; it remains liquid even after being left there for several hours, but it quickly solidifies as soon as the sample container is shaken. What’s going on? Could any senior brother give some advice on the above issues? Thank you
It shouldn’t oxidize that quickly in the air, right?
There’s no one here at all; it seems like everyone is only interested in what interests them, which isn’t conducive to keeping forum users active
The samples that have just been taken are very hot. When left at rest, it remains in a supercooled state; upon being disturbed by external factors, the supercooled liquid rapidly solidifies into a solid. One reason for yellowing is impurities; since these are not visible when the substance is in liquid form, their color becomes apparent after it solidifies. Second, oxidation may occur, but maleic anhydride does not oxidize quickly. I suspect it is a small amount of colored substance produced by the self-polymerization of some maleic anhydride.