Process for production of acrylic acid or its derivatives from hydroxypropionic acid or its derivatives

摘要

Processes for the catalytic dehydration of hydroxypropionic acid, hydroxypropionic acid derivatives, or mixtures thereof to acrylic acid, acrylic acid derivatives, or mixtures thereof with high yield and selectivity and without significant conversion to undesired side products, such as, acetaldehyde, propanoic acid, and acetic acid, are provided.

主权项

1. A process for converting hydroxypropionic acid, hydroxypropionic acid derivatives, or mixtures thereof to acrylic acid, acrylic acid derivatives, or mixtures thereof comprising the following steps:
a) Providing an aqueous solution comprising hydroxypropionic acid, hydroxypropionic acid derivatives, or mixtures thereof, wherein said hydroxypropionic acid is in monomeric form in said aqueous solution; b) Combining said aqueous solution with an inert gas to form an aqueous solution/gas blend; c) Evaporating said aqueous solution/gas blend to produce a gaseous mixture; and d) Dehydrating said gaseous mixture by contacting said gaseous mixture with a dehydration catalyst under a pressure of at least about 80 psig, producing said acrylic acid, acrylic acid derivatives, or mixtures thereof, wherein said catalyst comprises: (a) at least one condensed phosphate anion selected from the group consisting of formulae (I), (II), and (III), [PnO3n+1](n+2)− (I), [PnO3n]n+ (II), [P(2m+n)O(5m+3n)]n− (III), wherein n is at least 2 and m is at least 1, and (b) at least two different cations, wherein said catalyst is essentially neutrally charged, and further wherein the molar ratio of phosphorus to the at least two different cations is between about 0.7 and about 1.7.