Technique and installation for preparing guaiacol by continuously hydrolyzing diazonium salt of o-amino pheylmethyl ether

Abstract

The invention belongs to the technical field of guaiacol preparation, in particular to a technique and an installation for preparing guaiacol by continuously hydrolyzing diazonium salt of o-amino pheylmethyl ether, which solves the problems of the prior guaiacol production method, including low efficiency, high energy consumption, severe pollution and difficult continuous production. The installation comprises a hydrolysis reactor which consists of a rotating packed bed and a coil, the coil is axially vertically arranged under the rotating packed bed, a liquid outlet of the rotating packed bed is connected with a coil inlet, and a coil outlet is sequentially connected with a stirrer, a condenser and an output liquid storage tank. The method includes the following steps that: hydrolysate and extractant are mixed and preheated, and are then sent into the hydrolysis reactor along with the diazonium salt solution of o-amino pheylmethyl ether at the same time and heated to the hydrolysis temperature, so that the guaiacol is produced. The invention has the following advantages that: the production of by-products can be reduced, the yield is increased to more than 90 percent, the emission of the three wastes is reduced, the production cost is reduced, moreover, the equipment size is small, the startup / shutdown time is short, and mounting, operation and maintenance are convenient.

Description

technical field [0001] The invention belongs to the technical field of guaiacol preparation, and specifically relates to a process and a device for preparing guaiacol by continuous hydrolysis of a diazonium salt of anthranil. Background technique [0002] Guaiacol, scientific name o-hydroxyanisole, colorless or light yellow crystal or colorless to light yellow transparent oily liquid, flammable, has a special aromatic smell, exposed to air or sunlight gradually becomes dark, slightly soluble in water And benzene, easily soluble in glycerin, miscible with ethanol, ether, chloroform, etc. Guaiacol is an important chemical raw material widely used in the synthesis of medicines, spices and dyes. [0003] According to the raw materials, the preparation of guaiacol is divided into: catechol method and anthranil method. The catechol method is to prepare guaiacol by reacting catechol with methylating reagents such as methanol and monohalomethane under the action of a catalyst. Thi...

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Problems solved by technology

[0018] The hydrolysis reaction can only achieve the optimal selectivity of the main reaction in a certain hydrolyzate ratio, but with the evaporation of water, the continuous addition of non-volatile components in the diazonium salt solution and the generation of sulfuric acid in the hydrolysis reaction, It will lead to changes in the initial optimal composition of the hydrolyzate, and the content of the catalyst in the hydrolyzate will change, resulting in a decrease in the selectivity of the main product and an increase in by-products

At the same time, it can be seen from the colligative property of the solution that the boiling point of the hydrolyzed solution will continue to rise, thereby increasing the energy consumption required for evaporation.

[0019] (3), the evaporation of the product is limited

Due to the large volume of the reactor in the industry, coupled with the increase in production efficiency, the volume of the reactor is required to increase, resulting in a decrease in the surface area per unit volume, and the evaporation of the product is limited.

[0021] (4), product quality is not stable

[0022] Since the process is a batch operation, the conditions for producing each batch of products, such as the addition rate of the diazonium salt solution, the composition of the hydrolyzate, and the temperature control, are not exactly the same, which will change the selectivity of the main product, resulting in uneven quality of the product

[0023] In order to increase the yield of guaiacol by hydrolysis of diazonium salt and reduce by-products, Weng Liyong (Zhejiang Chemical Industry, 1992, 23(2): 57-59), Kong Huangkuan (CN02137265.9), Zhang Xiaoxi (CN 97118908.0) , Chen Minheng (CN 03141536.9), etc. have improved the traditional hydrolysis process, mainly optimizing the proportion of the hydrolyzate, improving the hydrolysis equipment, adding a phase transfer catalyst, etc., although the yield of guaiacol has been improved to a certain extent, but still The problems of low production efficiency and high energy consumption in the traditional method have not been completely solved

Yang Yuanyuan (dissertation: Zhejiang University, 2005, 3) prepared guaiacol by hydrolysis of diazonium salt in a pipeline. The inner diameter of the pipeline is 0.004m, the length is 23m, and the material flow rate is 8×10 -5 m 3 / h, under this condition, it can achieve rapid temperature rise, avoid back mixing and maintain the ratio of hydrolyzate, and the product yield has been improved to a certain extent, but with the increase of production capacity, the enlarged pipeline and material flow limit the rapid temperature rise. Thereby affecting the yield of the main product, industrial scale-up is difficult

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