US 9,809,526 B2
Method for the continuous dehydration of 3-hydroxypropionic acid to form acrylic acid
Tim Blaschke, Ekeren (BE); Ortmund Lang, Quirnbach (DE); Marta Zajaczkowski-Fischer, Neuhofen (DE); and Marco Hartmann, Jockgrim (DE)
Assigned to BASF SE, Ludwigshafen (DE)
Appl. No. 15/311,541
Filed by BASF SE, Ludwigshafen (DE)
PCT Filed May 13, 2015, PCT No. PCT/EP2015/060639
§ 371(c)(1), (2) Date Nov. 16, 2016,
PCT Pub. No. WO2015/177029, PCT Pub. Date Nov. 26, 2015.
Claims priority of application No. 14168770 (EP), filed on May 19, 2014.
Prior Publication US 2017/0081268 A1, Mar. 23, 2017
Int. Cl. C07C 51/46 (2006.01); C07C 51/377 (2006.01); C07C 51/43 (2006.01)
CPC C07C 51/46 (2013.01) [C07C 51/377 (2013.01); C07C 51/43 (2013.01)] 12 Claims
 
1. A process for continuously dehydrating aqueous 3-hydroxypropionic acid to acrylic acid, which comprises, in a first step i), converting an aqueous mixture of 3-hydroxypropionic acid and oligomeric 3-hydroxypropionic acid to acrylic acid in the liquid phase and at a pressure of less than 900 mbar and separating aqueous acrylic acid from the liquid phase by distillation and, in a second step ii), separating the aqueous acrylic acid obtained in step i) at a pressure of less than 900 mbar, by distillation into a crude acrylic acid phase and a water phase.