General procedure for the synthesis of 2-methylene-1,3-dioxane from 2-chloromethyl-1,3-dioxane (cas:54237-96-6) and sec-butanol: In a four-necked, 1-liter round-bottomed flask fitted with a thermometer, a reflux condenser, a pressurized dosing funnel, and a mechanical stirrer, 62.5 g of potassium hydroxide and 47 g of sec-butanol were added. The mixture was heated to 125 °C until all potassium hydroxide particles were completely dissolved. Subsequently, 37.5 g of 2-chloromethyl-1,3-dioxane synthesized according to the method of Example 1 was slowly added dropwise through the addition funnel. After the dropwise addition was completed, the reaction was continued for 2 hours. After completion of the reaction, the heating was stopped and 100 g of distilled water and 50 g of toluene were added to the reaction mixture. The mixture was transferred to a separatory funnel and the organic phase was separated. A sample of the reaction mixture was analyzed by gas chromatography to confirm that 2-chloromethylidene-1,3-dioxepane was completely converted and that the crude yield of 2-methylidene-1,3-dioxepane was 72%.
