Synthesis process of methylparaben

Abstract

The invention relates to a synthesis process of food preservative, and in particular relates to a synthesis process of methylparaben. The synthesis process of methylparaben is simple in operation, short in time consumption and low in pollution. The synthesis process comprises the steps of: adding p-hydroxybenzoic acid and methanol into a round-bottom flask according to the molar ratio of (1: 1.5)-(1: 4.0), and then adding 0.1-0.6g / g of catalyst sodium hydrogen sulfate into the mixture; putting the round-bottom flask into a microwave oven; preheating to dissolve the raw materials, adjusting the microwave output power to 450W after dissolving and further heating; timing when distillate appears in a water separator; carrying out reaction for 3-18minuest, then pouring out reaction liquid, and leaving the catalyst in a solid state in the round-bottom flask; distilling the reaction liquid, evaporating out excessive methanol, pouring 5% of sodium hydrogen carbonate while hot, and separating out ester from water; and filtering, washing and drying to obtain the finished product.

Description

Technical field: [0001] The present invention relates to a kind of synthesis technique of food preservative, more specifically, relate to the synthesis technique of methylparaben. Background technique: [0002] Methylparaben, also known as methyl p-hydroxybenzoate, the molecular formula is C 8 h 8 o 3 , the structural formula is shown in the figure below. [0003] [0004] Methylparaben [0005] Paraben is an internationally recognized broad-spectrum high-efficiency food preservative. The United States, Europe, Japan, Canada, South Korea, Russia and other countries allow paraben to be used in food. It is widely used in condiments such as soy sauce and vinegar, pickled products, baked food, sauce products, beverages, rice wine, and preservation of fruits and vegetables. my country's GB2760 stipulates that ethylparaben, propylparaben and sodium methylparaben, sodium ethylparaben and sodium propylparaben can be used as food preservatives. [0006] Due to its phenolic h...

AI Technical Summary

Problems solved by technology

[0007] The synthesis of parabens is usually based on concentrated sulfuric acid as a catalyst and esterification of alcohol and p-hydroxybenzoic acid as raw materials. This method has the disadvantages of poor product quality, difficult product separation, waste liquid corrosion equipment, and environmental pollution.

In recent years, there has been a method of catalyzing the synthesis of solid superacids and insoluble heteropolyacids, but the preparation of catalysts in this method is complicated and the reaction time is long

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