Preparation method of n-butyl benzoate

Abstract

The invention discloses a preparation method of n-butyl benzoate. The preparation method mainly comprises the following steps of: taking benzoic acid as a raw material, enabling the benzoic acid to react with n-butyl alcohol under the existence of a solid acid catalyst to obtain a crude product, then neutralizing the crude product by using solid alkali, and then rectifying and purifying to obtain the finished product, namely the n-butyl benzoate. The preparation method disclosed by the invention is simple, convenient and stable in operation process, little in three-waste pollution and suitable for industrial production.

Description

technical field [0001] The present invention relates to the manufacture method of chemical product, particularly a kind of manufacture method of n-butyl benzoate. Background technique [0002] N-butyl benzoate is a colorless, transparent liquid with a fruity aroma. It is mainly used as a solvent for resins, paints, etc., and as a raw material for spices. It has a wide range of uses. [0003] At present, n-butyl benzoate is produced by the esterification reaction of benzoic acid and n-butanol with concentrated sulfuric acid as a catalyzer. This method has disadvantages such as large consumption of sulfuric acid, many side reactions, serious corrosion, troublesome post-processing and environmental pollution. In recent years, people have used various solid superacids, heteropolyacids, activated carbon immobilized heteropolyacids, some Lewis acids or immobilized Lewis acids as esterification catalysts and achieved good results. Among them, p-toluenesulfonic acid (Fujian Chemic...

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Problems solved by technology

[0005] 1, because the unreacted benzoic acid content in the material after the reaction affects the acid value of the finished product after rectification, so the literature adopts the method for washing the organic layer after the reaction with water, dilute sodium carbonate solution and water to remove the unreacted benzoic acid. Benzoic acid, which will generate a large amount of wastewater, and n-butanol in the organic layer will also be washed into the wastewater, resulting in increased consumption of n-butanol and difficulties in wastewater treatment

According to the actual production situation, every 1 ton of finished products will produce 4 tons of waste water, and the COD value of the waste water is about 40,000, which brings huge pressure on environmental protection.

[0006] 2. N-butanol is put into the reaction kettle at one time for reflux and water separation reaction, resulting in too fast reaction speed and excessive reflux in the early stage; it is difficult to heat up in the later stage reaction and the reaction time is prolonged

The amount of n-butanol used in the literature is much more than the theoretically required amount of the reaction. The excess n-butanol increases the concentration of the reactants, and at the same time acts as a solvent and takes out the water generated by the reaction, so the early stage of the reaction is very fast , the return flow is very large, so there are potential safety hazards in industrial production, and safety accidents such as flushing are prone to occur

And when the benzoic acid concentration in the late stage of the reaction decreases and causes the reaction speed to decline, there is still a large amount of n-butanol in the reaction system, which makes it difficult to increase the reaction speed, thereby prolonging the reaction time

In addition, investing too much n-butanol will reduce the utilization rate of equipment, increase energy consumption, and etherification reaction will easily occur to increase the consumption of n-butanol

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