US 11,655,209 B2
Process for synthesizing azo compounds
Jean-Marc Sage, Pierre-Benite (FR); and Jean-Michel Bossoutrot, Pierre-Benite (FR)
Assigned to Arkema France, Colombes (FR)
Appl. No. 16/979,582
Filed by Arkema France, Colombes (FR)
PCT Filed Mar. 14, 2019, PCT No. PCT/FR2019/050565
§ 371(c)(1), (2) Date Sep. 10, 2020,
PCT Pub. No. WO2019/175510, PCT Pub. Date Sep. 19, 2019.
Claims priority of application No. 1852264 (FR), filed on Mar. 16, 2018.
Prior Publication US 2020/0407312 A1, Dec. 31, 2020
Int. Cl. C07C 253/30 (2006.01); C07C 255/65 (2006.01); B01J 27/053 (2006.01); B01J 27/18 (2006.01)
CPC C07C 253/30 (2013.01) [B01J 27/053 (2013.01); B01J 27/1802 (2013.01)] 7 Claims
 
1. A process for synthesizing an azo compound, the process comprising the steps of:
a) reacting an oxidizing agent with a hydrazo compound, at least one catalyst comprising a water-soluble compound chosen from alkali metal or ammonium salts of molybdenum, alkali metal or ammonium salts of tungsten, phosphomolybdic acid and alkali metal or ammonium salts thereof, phosphotungstic acid and alkali metal or ammonium salts thereof, molybdosulfates and mixtures thereof, and at least one compound of formula (I):
(R1)(R2)C(PO3(R3)2)2  (I)
so as to form a solution containing an azo compound,
wherein:
R1 and R2, which may be identical or different, are chosen independently of each other from a hydrogen atom, a saturated or unsaturated, linear, branched or cyclic, optionally substituted hydrocarbon chain, —OH and —O-alkyl, where “alkyl” represents a saturated, optionally substituted, linear or branched hydrocarbon chain comprising from 1 to 6 carbon atoms; and
R3 is chosen from a hydrogen atom and metal or ammonium ions;
b) recovering all or part of the reaction mixture obtained in step a);
c) separating the reaction mixture recovered into a fraction containing the azo compound and a fraction of residual aqueous liquors; and
d) recovering, and optionally washing and drying, the azo compound obtained.