	US 11,919,846 B2
	Continuous process for preparing methacrolein
Alexander Lygin, Griesheim (DE); Steffen Krill, Muehltal (DE); Matthias Grömping, Darmstadt (DE); Torsten Balduf, Pfungstadt (DE); and Rudolf Burghardt, Darmstadt (DE)
Assigned to Röhm GmbH, Darmstadt (DE)
Appl. No. 17/269,648
Filed by Röhm GmbH, Darmstadt (DE)
PCT Filed Aug. 1, 2019, PCT No. PCT/EP2019/070784 § 371(c)(1), (2) Date Feb. 19, 2021, PCT Pub. No. WO2020/038696, PCT Pub. Date Feb. 27, 2020.
Claims priority of application No. 18189862 (EP), filed on Aug. 21, 2018.
Prior Publication US 2021/0363089 A1, Nov. 25, 2021
Int. Cl. C07C 45/75 (2006.01); C07C 45/82 (2006.01); C09K 15/08 (2006.01); C07C 47/22 (2006.01)

CPC C07C 45/75 (2013.01) [C07C 45/82 (2013.01); C09K 15/08 (2013.01); C07C 47/22 (2013.01)]

17 Claims

1. A continuous process for preparing methacrolein by a Mannich condensation reaction of formaldehyde with propanal, said comprising:

introducing a methacrolein polymerization inhibitor into a production process system, and

recycling a part of said methacrolein polymerization inhibitor back into a reactor where the Mannich condensation reaction is carried out,

said production process system comprising flow lines, a reactor, a distillation column, a reboiler, a condenser, and a phase separator,

wherein the methacrolein polymerization inhibitor is introduced into the distillation column in the production process system.