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A kind of dilute sulfuric acid recycling method

A technology of dilute sulfuric acid and sulfuric acid, which is applied in the preparation of sulfonic acid and organic chemistry, and can solve problems such as waste of resources, serious environmental pollution, and difficulty in separation and removal

Active Publication Date: 2017-07-11
SHAOXING UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

If these dilute sulfuric acid is discharged into the environment without treatment, it will cause water or soil acidification, endanger the ecological environment, and waste a lot of resources
Patents such as CN102951627A use methods such as production of gypsum or phosphate fertilizer to process dilute sulfuric acid, but with the development of the chemical industry and the needs of environmental protection, this treatment method can no longer meet the demand. Therefore, dilute sulfuric acid needs to be concentrated and recycled
The naphthalene-based water-reducing agent obtained by this method has a low concentration and contains about 20-25% of sodium sulfate (accounting for powder), which increases the loss of concrete slump and is not suitable for self-flowing grouting and preparation of pumped concrete, which affects construction progress and quality
Na in low-concentration naphthalene-based superplasticizer products 2 SO 4 Crystallization will occur below 15°C, seriously affecting the accuracy of concrete metering pumps and water-reducing effect
Separation of Na 2 SO 4 The method of CN103755203A is to dilute the product with water, add lime to make excessive sulfuric acid produce calcium sulfate, and separate through filtration, separation and removal are difficult, and the separated waste acid or salt has problems such as large environmental pollution

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Embodiment 1: Preparation of β-naphthalenesulfonic acid.

[0029] Add 134g of industrial naphthalene (purity ≥ 95%, 1.0mol), 121g of sulfuric acid (mass concentration: 85%, 1.05mol) into the reaction flask, with a 20cm rectification column on the reaction flask, and raise the temperature to 160-170°C to react the refined After distillation for 1.5h, 16g of water was produced during the period. After the reaction, the sample was analyzed by liquid chromatography to obtain 8.51% of α-naphthalenesulfonic acid and 88.3% of β-naphthalenesulfonic acid.

Embodiment 2

[0030] Example 2: Preparation of naphthalene-based cement water reducer.

[0031] Add 134g industrial naphthalene (purity ≥ 95%, 1.0mol) and 178.0g sulfuric acid (mass concentration: 55%, 1.0mol) to the reaction flask, heat up to 135°C and start back distillation, produce water, continue to rectify and heat up to 165~ React at 175°C for 9 hours. After the reaction, the measured acidity is 26%; cool down to 95°C, add 30.7g of paraformaldehyde (purity ≥ 99%, 1mol is calculated as formaldehyde) and 54.0g of water, and gradually heat up to 100-110°C , keep warm for 8h, add water to control the polymerization under proper viscosity during the keep warm process. After the reaction is finished, add liquid caustic soda to adjust the pH=6-8, and dry to obtain the naphthalene-based cement water-reducer. The sodium sulfate content is 8.7%.

Embodiment 3

[0037] Example 3: Preparation of MF dispersant.

[0038]Add 150g industrial methylnaphthalene (purity ≥95%, 1.0mol), 196.0g sulfuric acid (mass concentration: 55%, 1.1mol) to the reaction flask, heat up to 135°C and start back distillation, produce water, continue to rectify and heat up to React at 160-170°C for 9 hours. After the reaction, the measured acidity is 28%. Cool down to 95°C, add 30.7g of paraformaldehyde (purity ≥ 99%, 1mol is calculated as formaldehyde) and 54.0g of water, gradually raise the temperature to 100-110°C, keep warm for 8 hours, add water during the heat preservation process to control polymerization at an appropriate viscosity. After the reaction is finished, add liquid caustic soda to adjust pH=6-8, and dry to obtain MF dispersant.

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Abstract

The invention discloses a recycling method for dilute sulphuric acid. The recycling method is characterized by including the following steps that dilute sulphuric acid and dicyclic aromatic hydrocarbon or / and polycyclic aromatic hydrocarbon are rectified in a reaction still with a rectification function, in the rectification process, water serves as a light component and is extracted from the top of a rectifying tower, the concentration of sulphuric acid in the still is increased, and the temperature of the still is increased; when the mass concentration of the sulphuric acid in the still is larger than 63%, the temperature in the still ranges from 150 DEG C to 175 DEG C, the sulphuric acid and dicyclic aromatic hydrocarbon or / and polycyclic aromatic hydrocarbon are subjected to a sulfonation reaction, meanwhile, water is generated, the concentration of the sulphuric acid is decreased, the water is extracted through rectification, and circulation is conducted in this way till the sulphuric acid in the still reacts and is consumed completely. Rectification, concentration and utilization of the dilute sulphuric acid and sulfonation of dicyclic / polycyclic aromatic hydrocarbon are combined, and concentration and utilization of the dilute sulphuric acid can be achieved without high temperature.

Description

[0001] Technical field: [0002] The invention belongs to the field of chemical industry, and in particular relates to a recycling method for preparing related sulfonic acid products by combining concentration and sulfonation of dilute sulfuric acid. [0003] Background technique: [0004] Sulfuric acid is widely used in chemical, steel and other industries. However, during the application process of sulfuric acid in catalysis and dehydration, it becomes dilute sulfuric acid due to water absorption or reaction to generate water. The whereabouts of dilute sulfuric acid after losing dehydration and catalytic ability is a very thorny issue at present. If the dilute sulfuric acid is discharged into the environment without treatment, it will cause water or soil acidification, endanger the ecological environment, and waste a lot of resources. Patents such as CN102951627A use methods such as production of gypsum or phosphate fertilizer to process dilute sulfuric acid, but with the d...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C303/06C07C309/35
CPCC07C303/06C07C309/35
Inventor 季根忠章思怡戚天木李俊
Owner SHAOXING UNIVERSITY
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