A preparing method of 2-nitrobenzaldehyde

Abstract

The invention discloses a preparing method of 2-nitrobenzaldehyde. 2-nitrotoluene is adopted as a raw material and is brominated with bromine under catalytic function of azo-bis alkyl nitrile to generate 2-nitrobenzyl bromide and hydrogen bromide. The 2-nitrobenzyl bromide is hydrolyzed under catalytic function of an aqueous carbonate solution to generate 2-nitrobenzyl alcohol. The 2-nitrobenzyl alcohol is oxidized with hydrogen peroxide under catalytic function of sodium hydroxide to generate the objective compound, namely the 2-nitrobenzaldehyde. A hydrogen peroxide oxidation manner is adopted by the method, thus improving cleanliness of industrial preparation reactions, and reducing environment pollution. Oxidation is catalyzed by adopting the inorganic solid alkali catalyst and no metal organic complex catalyst is used, thus improving reaction stability and greatly reducing the cost of industrial preparation. An azo-bis alkyl nitrile solid catalyst in place of a peroxydicarbonate liquid catalyst is adopted to catalyze the bromination, thus improving reaction operation safety of industrial preparation. The method increases the product yield. The yield of the method is increased by about 5% than that of traditional industrial methods at present. The total yield can reach 77% and product purity is higher than 99%.

Description

technical field [0001] The present invention relates to a kind of preparation method of known compound, specifically a kind of industrial clean preparation method of o-nitrobenzaldehyde. Background technique [0002] O-Nitrobenzaldehyde is a yellowish solid with a melting point of 41-43°C, insoluble in water, and easily soluble in organic solvents such as alcohols, ethers, aromatic hydrocarbons, halogenated hydrocarbons, and esters. The molecular formula of o-nitrobenzaldehyde is C 7 h 5 NO 3 , the relative molecular mass is 151.1. The chemical structural formula of o-nitrobenzaldehyde is: [0003] [0004] O-nitrobenzaldehyde is a class of important pharmaceutical intermediate organic functional materials, mainly used for the preparation of nifedipine and other drugs for the prevention and treatment of hypertension and cardiovascular diseases, as well as for the preparation of expectorant and anti-inflammatory drugs such as ambroxine. O-nitrobenzaldehyde is also an ...

AI Technical Summary

Problems solved by technology

This method requires the application of chlorine, and benzyl chloride has a lacrimal effect; the second-step nitration reaction uses a mixture of nitric acid and niobium pentoxide solid superacid as a nitrating agent, and the selectivity of ortho-position nitration is poor, but still forms o-nitrobenzyl chloride, meta The three isomers of nitrobenzyl chloride and p-nitrobenzyl chloride are difficult to separate, and they also have a strong lachrymatory effect, and metal oxides are difficult to recycle.

[0008] (3) Using o-nitrotoluene as a raw material, react with bromine to form o-nitrobenzyl bromide, then catalyze hydrolysis with sodium carbonate to form o-nitrobenzyl alcohol, and further synthesize o-nitrobenzene through metal-organic complex catalyzed oxygen oxidation Formaldehyde, although significantly improved reaction selectivity, has improved productive rate, but the organic peroxide liquid catalyst of bromination reaction procedure, its thermal stability of industrial application is poor; The used metal organic complex catalyst of the 3rd step oxidation reaction procedure is difficult Regeneration, and oxygen oxidation is a gas-liquid phase reaction system, which needs to be reacted under certain pressure conditions. Therefore, there is no obvious advantage in production costs and industrial operations.

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