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ChemicalBook CAS DataBase List Propylparaben
94-13-3

Propylparaben synthesis

6synthesis methods
Produced by esterfying p-hydroxybenzoic acid with n-propanol, using an acid catalyst such as sulfuric acid and an excess of propanol. The materials are heated in a glass-lined reactor under reflux. The acid is then neutralized with caustic soda and the product is crystallized by cooling. The crystallized product is centrifuged, washed, dried under vacuum, milled and blended, all in corrosion-resistant equipment to avoid metallic contamination.
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Yield:94-13-3 93.4%

Reaction Conditions:

with methanesulfonic acid;trimethyl-(2-hydroxyethyl)ammonium chlorideReflux;

Steps:

3.1; 3.2; 3.3 Example 3 Preparation of parabens:

In the first step, 1 mol of choline chloride and 2 mol of methanesulfonic acid were added to the reaction vessel, and the mixture was stirred at 80 ° C until the total dissolution was low. Co-melting solvent;In the second step, after cooling the reaction system to room temperature, 1 mol of p-hydroxybenzoic acid and 1.2 mol of n-propanol are added, the temperature is slowly raised, and the reaction is refluxed, and TLC is monitored until the end of the reaction;In the third step, the reaction solution is cooled to room temperature, a solid is precipitated, suction filtration, and the filter cake is washed with a small amount of water.The paraben was obtained, the yield was 93.4%, m.p. 96-97 ° C; the filtrate was recovered to obtain a eutectic solvent.

References:

CN109970557,2019,A Location in patent:Paragraph 0042; 0043; 0044; 0045; 0046; 0047; 0048

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