摘要:
Methyl 4-pentenoate is isolated from mixtures containing this and methyl 3-pentenoate by a process in which from 0.25 to 0.4 part by weight of water is added per part by weight of methyl 4-pentenoate, and the azeotrope of methyl 4-pentenoate and water is distilled off.
摘要:
Very pure maleic anhydride having a stable color is obtained by fractional distillation of crude maleic anhydride by a method in which the maleic anhydride vapor separated off from low boilers and high boilers is partially condensed so that from 0.5 to 15% by weight of the maleic anydride vapor is separated off from the vapor phase as a liquid precondensate, and the remaining very pure maleic anhydride vapor is then completely condensed.