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The manufacturing method
of benzaldehyde
Benzaldehyde is an important organic chemical raw material, which is widely used in medicine, pesticides, spices, plastics and dyes. This article will introduce the manufacturing methods of benzaldehyde, including chemical synthesis and biological methods.
1. Chemical Synthesis
1. Benzyl Alcohol Oxidation
Benzyl Alcohol Oxidation is one of the commonly used benzaldehyde manufacturing methods. The method uses benzyl alcohol as raw material to produce benzaldehyde through oxidation reaction. Commonly used oxidants include potassium permanganate, potassium dichromate, hydrogen peroxide, etc. Among them, the acidic potassium permanganate oxidation method is more commonly used, and the reaction formula is as follows:
reaction conditions: under acidic conditions, the temperature is controlled at 60-80°C, and the reaction time is about 2-3 hours.
advantages: easy access to raw materials, simple operation and low cost.
Disadvantages: a large amount of waste water is produced, the environment is polluted, and the yield is not high.
2. Methyl Benzoate Reduction
The methyl benzoate reduction method is to use methyl benzoate as raw material to produce benzaldehyde through reduction reaction. Commonly used reducing agents include lithium aluminum hydride, sodium borohydride, and the like. Reaction formula is as follows:
reaction conditions: under the protection of inert gas, heating to 80-120 DEG C, reaction time is about 2-4 hours.
advantages: higher yield, better product quality.
disadvantages: high cost of raw materials, the operation is more complex.
2. biological method
biological method is a method of converting benzyl alcohol or benzoic acid into benzaldehyde by the action of microorganisms or enzymes. Compared with the chemical synthesis method, biological method has the advantages of environmental protection, energy saving and high efficiency, and has gradually become a research hotspot.
1. Microbial oxidation
Microbial oxidation is the use of certain microorganisms to oxidize benzyl alcohol to benzaldehyde. Commonly used microorganisms are Pseudomonas, Alcaligenes and so on. The reaction conditions of this method are mild, but it takes a long time to cultivate and adapt, and the type and activity of microorganisms have a great influence on the reaction.
2. Enzyme-catalyzed
Enzyme-catalyzed method is a method of using specific enzymes to catalyze the conversion of benzyl alcohol or benzoic acid to benzaldehyde. Commonly used enzymes are alcohol dehydrogenase, aldehyde dehydrogenase, etc. The method has high stereoselectivity and regioselectivity, and high purity benzaldehyde can be obtained. However, the source and stability of the enzyme are the key factors restricting the application of the method.
To sum up, there are many manufacturing methods of benzaldehyde, including chemical synthesis and biological method. Different methods have different advantages and disadvantages and scope of application, and suitable methods should be selected according to specific production needs and conditions. At the same time, with the continuous improvement of environmental awareness and the continuous development of biotechnology, the application prospect of biological method in the manufacture of benzaldehyde will be more broad.