Production method for naphthalene high-concentration water reducer

Abstract

The invention discloses a production method for a naphthalene high-concentration water reducer. The production method comprises the following steps: (1), preparing industrial naphthalene, 98% concentrated sulfuric acid and 37% formaldehyde in a weight ratio being 1:0.889:0.598; (2), adding the industrial naphthalene; (3), sulfonating, namely adding the concentrated sulfuric acid within 25-30 minutes while rising a temperature of the naphthalene to 150 DEG C; after adding the acid, carrying out sulfonation reaction at 160-165 DEGC; increasing steps of circulating a solvent and removing residual solvent in the sulfonating process, and controlling acidity to 26-27%; (4), hydrolyzing, namely adding water into reaction liquor and hydrolyzing for 15 minutes at 110-125 DEG C; (5), condensing, namely adding the formaldehyde within 2 hours when the temperature is 102 +/-2 DEG C, condensing and preserving the heat to react for 3 hours, and controlling the temperature to 115-125 DEG C and controlling the pressure to 0.10-0.15MPa; and (6), neutralizing. According to the production method, a conversation ratio of a beta-naphthalenesulfonic acid-formaldehyde condensation compound is greatly increased, the time is shortened, the energy consumption is lowered, and the discharge of waste gas is reduced.

Description

technical field [0001] The invention relates to a production method of a naphthalene-based high-concentration product, in particular to a production method of a naphthalene-based high-concentration water-reducing agent. Background technique [0002] With the rapid development of my country's economy and the improvement of construction level, the requirements for concrete quality are getting higher and higher. High-efficiency water-reducing agent is a kind of high-efficiency water-reducing agent commonly used in the current domestic construction industry, especially naphthalene-based high-efficiency water-reducing agent is one of the important components widely used in the preparation of high-performance concrete. The normal pressure production process in the prior art is: 1) sulfonation reaction of industrial naphthalene and concentrated sulfuric acid; 2) hydrolysis; 3) condensation; 4) neutralization; 5) filtration. This technique has the following shortcomings: 1. In the ...

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Problems solved by technology

This technique has the following disadvantages: 1. In the sulfonation reaction, naphthalene and the vitriol oil generate β-naphthalene sulfonic acid and water, and the generated water will dilute the vitriol oil, thereby affecting the continuation of the reaction, reducing the rate of sulfonation reaction and the sulfonic acid. In the prior art, either adopt benzene with water to remove the water generated by the reaction, so that the reaction can proceed smoothly; or, feed sulfur trioxide into the reactor so that the concentration of the concentrated sulfuric acid does not decrease; However, the toxicity of benzene is relatively high, which is unfavorable to the environment, and the post-treatment is cumbersome and high in cost; and the introduction of sulfur trioxide makes the reaction not mild enough, and the operation risk is relatively large; there is another kind of water absorption by using anhydrous sodium sulfate. The water generated by the reaction is adsorbed to ensure the smooth progress of the reaction and improve the sulfonation efficiency

But still need to add anhydrous sodium sulfate, increased waste residue

2. In the condensation process, because formaldehyde is volatile, a part of formaldehyde is volatilized with water vapor during the condensation reaction of the atmospheric pressure process, which causes waste of raw materials on the one hand, and is discharged as waste gas on the other hand, polluting the environment. And its strong irritant will cause harm to the human body

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