3-Amino-4-methoxy acetanilide (II) preparation method

Abstract

The invention relates to a preparation method of organic compounds, and especially relates to a 3-amino-4-methoxy acetanilide (II) preparation method which includes the following steps: 1, mixing 3-nitro-4-methoxy acetanilide (I), a solvent and a catalyst in a reaction kettle, adding an additive or not, heating to 40-80 DEG C, adding a reducing agent within 1-3 hours, and reacting completely; 2, hotly filtering, recycling the additive, and applying mechanically into next batch of reaction; and 3, distilling the filtrate for recovery of methanol, applying mechanically into next batch of reaction, and cooling and filtering residual liquid to obtain 3-amino-4-methoxy acetanilide (II) and a liquid waste. The beneficial effects of the method are mainly as follows: commercialized 40-80 wt % hydrazine hydrate is chosen as the reducing agent, use of high risk hydrogen and generation of a large amount of iron sludge can be avoided, the hydrazine hydrate is convenient to store, transport and accurate to measure; reaction equipment is simple, special equipment and A-class explosion-proof workshops are not needed, and equipment and plant investment is small.

Description

technical field [0001] The invention relates to a method for preparing organic compounds, in particular to a method for preparing 3-amino-4-methoxyacetanilide (II). Background technique [0002] 3-Amino-4-methoxyacetanilide [also known as 2-amino-4-acetamidoanisole, commonly known as "reduced substance", 】It is an important chemical intermediate, which has been widely used as a raw material for the synthesis of disperse blue 79, disperse blue 301, disperse blue 270 and other dyes for a long time. [0003] At present, there are mainly two routes for the production of 3-amino-4-methoxyacetanilide in China: the new process and the old process. Among them, the new process mainly refers to the use of 2,4-dinitrochlorobenzene (III) as raw material to obtain 2,4-dinitroanisole (IV) through etherification, and catalytic hydrogenation reduction to obtain 2,4-dinitroanisole (IV). Aminoanisole (V), acylation process to obtain 3-amino-4-methoxyacetanilide (II) crude product, through ...

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Problems solved by technology

[0005] Although there are some materials [CN103396318, CN103524371, CN1861577] to report the progress status of this technological process, there is no report of large-scale production as yet, and the overall technological conditions are still unstable at present, and the main problems of memory include: (1) etherification reaction process 2,2',4,4'-tetranitrodiphenyl ether is easily produced as a by-product, which not only affects the purity and yield of 2,4-diaminoanisole (V), but also 3-amino-4-methanol The purity of oxyacetanilide (II); (2) the catalytic hydrogenation reduction process is carried out under the hydrogen condition of relatively high temperature and certain pressure, needs Class A explosion-proof workshop and special reaction equipment, and reaction process easily produces a large amount of tar, Leading to the poisoning of noble metal catalysts, resulting in low catalyst application times and high costs; (3) tar produced by catalytic hydrogenation is brought into the acylation reaction, resulting in low purity of 3-amino-4-methoxyacetanilide (II) , needs multiple purifications; (4) 2,4-diaminoanisole (V) will produce about 5% of 2,4-diacetamidoanisole during selective acylation, which also gives 3- The purification of amino-4-methoxyacetanilide (II) increases difficulty; (5) because by-product is many and final product 3-amino-4-methoxyacetanilide (II) crude product needs repeated purification, therefore, the whole article Unstable process yield and large amount of waste water

[0008] The main problem of this process route is that the iron powder reduction step uses a large excess of iron powder. After the reaction is completed, a large amount of hot water needs to be used to wash the iron sludge, which consumes a lot of energy and has a lot of waste water and solid waste. Industrial policy is clearly listed as the process of eliminating or immediately eliminating; Yet, this process route has been the stable process route of long-term production, and the yield and the quality of 3-amino-4-methoxyacetanilide (II) product all have good Reproducibility, especially the acylation and nitration steps basically achieve the same conversion. Therefore, it is necessary to develop a new reduction method to replace the iron powder reduction method. It is of great significance for the stable production of reduced substances and even the entire dye industry.

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