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ChemicalBook CAS DataBase List Ethyl 4,4-difluoro-3-oxobutanoate

Ethyl 4,4-difluoro-3-oxobutanoate synthesis

10synthesis methods
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Yield:352-24-9 95.5%

Reaction Conditions:

Stage #1:ethyl acetate with sodium ethanolate at 25;
Stage #2:ethyl difluoroacetate at 10 - 65;
Stage #3: with sulfuric acid;water at 20 - 25; for 0.333333 h;Product distribution / selectivity;

Steps:

5
45.9 g (0.53 mol) of ethyl acetate were initially charged at 25°C and 14.96 g (0.22 mol) of sodium ethoxide (98%) were added with stirring. After the suspension had been cooled to 5°C, 24.9 g (0.2 mol) of ethyl difluoroacetate (99.88%) were metered in at internal temperature from 10 to 25°C within 2.0 hours. Thereafter, the reaction mixture was heated to 65°C, stirred at this temperature for a further 2 hours and then cooled to 200C. 20.4 g (0.2 mol) of sulfuric acid (98%, comprises 2% water) were metered into the solution (85.6 g) at from 20 to 25°C within 20 minutes, which formed a thick suspension (precipitation of sodium hydrogensulfate). The precipitated salt was also filtered off and the solid was washed with ethyl acetate. The filtrate (166.1 g) comprised 19.1 % by weight of the desired product of value (GC analysis, quantification with internal standard). The yield (based on ethyl difluoroacetate used) was 95.6%.

References:

BASF SE WO2009/106619, 2009, A1 Location in patent:Page/Page column 7

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