Continuous alkylation of cpds. contg. active methylene gps.

Alkylation with (B) alkyl halides, -mesylates and -tosylates, takes place by passing a gaseous mixt. of cpd. (A) contg. acid CH gp. and (B) through a catalyst bed of alkali carbonate or bicarbonate supporting an adsorbed phase transfer catalyst. The process pref. takes place at 150-200 (170-180) deg. C under pressure ((10-30) x 10 power 5)/760 esp. (20 x 10 power 5)/ 760 Pa. The reaction prods. are recovered by condensation at the outlet of the column contg. the catalyst bed. (A) is esp. a malonate diester, an acetoacetate ester or acetyl acetone. The phase transfer catalyst can be tetrabutyl phosphonium bromide, a polyethylene glycol, esp. Carbowax 6000, or a crown ether, esp. 18-crown-6- or dibenzo-18-crown-6. K2CO3 or NaHCO3 is used as base and catalyst-carrier. Molar ratio base: (A) is 2.5 : 1. Molar ratio (B) : (A) is 1.5-1.; The throughput of reactants through column can be 1-5 ml/hr. vol. of column. The process is carried out without solvents and without stirring. Pure prods. are obtd. at a high reaction rate.