the reaction mixture is held at 10 u00b0 c for 2 hours upon warming up to 1 u00b0 c the reaction mixture is neutralized with a mixture of concentrated hcl 60 ml and water 150 ml the phases are separated and the organic phase is transferred to another reactor the reaction mixture is concentrated by distillation sodium ethylate 46 g is added after cooling down to 75 u00b0 c the reaction mixture is heated to 120 u00b0 c and the remaining dimethoxymethane and the formed ethanol is distilled off upon cooling down to 20 u00b0 c the reaction mixture is neutralized with a mixture of concentrated hcl 60 ml and water 150 ml the phases are separated and the organic phase is dried with magnesium sulfate and concentrated in vacuo to yield the crude product 128 g 80 yield analogously to example 1 2 chloro 6 fluorobenzylchloride cfbc is treated with magnesium a carbonylation reagent and sodium ethylate as base in different solvents and at different temperatures the relative amounts of the reactands and solvents the reaction temperature of the carbonylation step and yields are shown in the following table i table i__________________________________________________________________________examples 2 to 15 carbonyl carbonylation temperature yieldexampleinitiator solvent mg cfbc ation agent agent cfbc naoet cfbc u00b0 c __________________________________________________________________________2 dbe tba 5 dec 5 1 8 10 313 dbe dmm 2 dec 5 1 5 10 754 dee mtbe 2 dec 5 1 8 10 755 dee tba 2 dec 5 2 4 10 53 tol6 dbe dmm 2.