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ChemicalBook CAS DataBase List 2,2-Dimethyl-1,3-dioxane-4,6-dione
2033-24-1

2,2-Dimethyl-1,3-dioxane-4,6-dione synthesis

3synthesis methods
2,2-Dimethyl-1,3-dioxane-4,6-dione is usually prepared by condensation of malonic acid with acetone in acetic anhydride in the presence of sulfuric acid. Excellent yield of the product was achieved when acetic anhydride was added in a slow, controlled manner to a mixture of acetone, malonic acid and an acid catalyst.
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Yield:2033-24-1 87.2%

Reaction Conditions:

Stage #1: malonic acidwith acetic anhydride;toluene-4-sulfonic acid for 0.5 h;Inert atmosphere;
Stage #2: acetone at 10 - 24; for 3 h;Inert atmosphere;Reagent/catalyst;Temperature;

Steps:

1-2 Preparation Example 2

Under nitrogen protection, in the reaction flask, add 227g of acetic anhydride, 213g of malonic acid and 13g of p-toluenesulfonic acid in sequence, stir for about 30min, control the temperature to 10°C, add 128g of acetone dropwise, and finish dropping in about 2 hours. Incubate the reaction at 24°C for about 1 hour, control in the middle, and the conversion rate of malonic acid is more than 99% as qualified, after passing, cool down to below -5°C, stir for crystallization for 1 hour, suction filter, and dry the filter cake to obtain Michael's acid. The yield was 87.2%.

References:

CN115141147,2022,A Location in patent:Paragraph 0041-0043

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