Patent ID: 8779210

Claim:
A process for the preparation of 2-methyl-4-(2,6,6-trimethyl-1-cyclohexene-1-yl)-2-butenal (MTCB) which comprises: (1) providing an aqueous mixture comprised of MTCB and a dipolar aprotic compound which is selected from the group consisting of hexamethylphosphorous triamide (HMPT), 1-methyl-2-pyrrolidone (NMP), 1-ethyl-2-pyrrolidone (NEP) and urea derivatives of the following formula: wherein R 1 , R 2 , R 3 and R 4 may each independently be H or a C 1 -C 4 alkyl group and wherein R 2 and R 3 may be part of a heterocyclic group, and (2) separating MTCB product from the aqueous mixture to form a product stream comprising the MTCB and an aqueous waste stream comprising the dipolar aprotic compound; and (3) treating the aqueous waste stream comprising the dipolar aprotic compound to remove the dipolar aprotic compound therefrom by: a) an adsorption step which comprises bringing the aqueous waste stream into contact with a porous adsorbent, wherein the porous adsorbent is chosen such that the dipolar aprotic compound adsorbs more readily to the porous adsorbent than water; and b) a desorption step which comprises bringing the porous adsorbent into contact with a desorbing agent which comprises methanol to thereby form a recovery solution comprising the desorbing agent and the dipolar aprotic compound.