Process for the separation of reaction mixtures and the recirculation of quaternary salts

A process for the removal and recovery of a quaternary salt A corresponding to the formula (Qn+)m(Ym−)n from a reaction mixture that also contains at least one hydroxyaromatic compounds B, one or more reaction products C and an optional solvent, comprising at least one of steps a) to e):

• a.)
• a1) adjusting the mass fractions cA of A and cB of B in the reaction mixture such that 0.001·cA<cB<4·cA, and
• a2) extracting the reaction mixture with water or with an aqueous solution to obtain an aqueous phase that contains A and an organic phase which comprises C and optionally isolating C from the organic phase,
• b.)
• b1) extracting an aqueous phase that contains A with an organic phase that contains 2 to 100 wt. % relative to the weight of the organic phase of B, and
• b2) returning the organic phase into the reaction mixture optionally after isolating the quaternary salts A from the organic phase,
• c.)
• c1) using the aqueous phase following the extraction referred to in b1) in the extraction referred to in a2), to form a closed water loop,
• d.)
• d1) extracting the water phase resulting from the extraction referred to in b1) with an organic phase before the extraction a2) to obtain a water phase having reduced content of B and an organic phase,
• e.)
• e1) adding B to the organic phase obtained in step d1), and using the result in step b1).
• wherein
• Qn+ denotes a hexaalkylguanidium ion or the formula (XR0+)t, wherein X stands for a Group Va or VIa atom, o stands for an integer between 1 and 4, t stands for an integer between 1 and 10, and R stands for C1-C18-alkyl or -cycloalkyl, C7- to C18-aralkyl, C6- to C18-aryl, independently of one another, and two substituent radicals R may in each case be replaced by a ring,
• Ym− denotes one or more members of the group consisting of halides, nitrates, sulfates, hydrogen sulfates, carbonates, hydrogen carbonates, phosphates, hydrogen phosphates, dihydrogen phosphates, tetrafluoroborates, carboxylates or hexafluorophosphates, and m stands for an integer between 1 and 3,
• B is a compound corresponding to the formula R—(OH)p, where R denotes an aromatic radical and p is an integer from 1 to 4, and where
• the solvent has a boiling point of 30 to 200° C.