Method for removing 2-mercaptopyridine-N-oxide in wastewater and recycling of 2-mercaptopyridine-N-oxide

A technology of pyrithione and oxide, which is applied to a method of removing 2-pyridine-N-oxide in wastewater and its recycling field, which can solve problems such as pollution and low content of pyrithione zinc, and achieve green process Environmental protection, chromaticity and suspended solids reduction, content reduction effect

Active Publication Date: 2016-05-04
浙江丽晶化学有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] How to remove and utilize 2-mercaptopyridine-N-oxide in wastewater containing 0.3-0.4% has not been reported in the literature, and it can usually be produced by adding zinc sulfate or copper sulfate to wastewater Zinc pyrithione (copper) is precipitated to remove 2-mercaptopyridine-N-oxide, but the content of zinc pyrithione (copper) recovered is low, further purification is required for effective utilization, and new pollution will be generated

Method used

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  • Method for removing 2-mercaptopyridine-N-oxide in wastewater and recycling of 2-mercaptopyridine-N-oxide

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] In a 5L glass reaction bottle, add 0.5 kg of toluene, add 4.5 kg of waste water containing 2-mercaptopyridine-N-oxide whose pH value was adjusted to 3-4 in advance, stir at room temperature for 1 hour, and sample the waste water for analysis. The waste water contains 0.042% of 2-mercaptopyridine-N-oxide, which is allowed to stand still for 0.5 hour, separated into layers, and the waste water layer is separated.

[0023] After the stratification is completed, add 0.01kg of deionized water, add 0.015kg of 30% sodium hydroxide solution dropwise, until the pH value is 9, stir for 0.5 hours, let stand for 0.5 hours, separate layers, separate the water layer 0.039kg, and its 2-mercapto The content of pyridine-N-oxide sodium salt was 40.3%.

Embodiment 2

[0025] In a 5L glass reaction bottle, add 0.6kg of dichloromethane, add 4.5kg of wastewater containing 2-mercaptopyridine-N-oxide with a pH value of 2-3, stir at room temperature for 1 hour, and sample and analyze the wastewater. Contain 0.033% of 2-mercaptopyridine-N-oxide, let stand for 0.5 hour, separate layers, and separate the waste water layer.

[0026] After the stratification is completed, add 0.015kg of deionized water, dropwise add 0.016kg of 30% sodium hydroxide solution, until the pH value is 9, stir for 0.5 hours, let stand for 0.5 hours, separate layers, separate the water layer 0.046kg, its 2-mercapto Pyridine-N-oxide sodium salt content was 35.5%.

Embodiment 3

[0028] In a 5L glass reaction bottle, add 0.5kg of methyl tert-butyl ether, add 4.5kg of waste water containing 2-mercaptopyridine-N-oxide whose pH value was adjusted to 4-5 in advance, stir at room temperature for 1 hour, and the waste water Sampling and analysis showed that the 2-mercaptopyridine-N-oxide contained in the waste water was 0.038%. After standing for 0.5 hour, the waste water layer was separated into layers.

[0029] After the stratification is completed, add 0.01kg of deionized water, dropwise add 0.015kg of 30% sodium hydroxide solution, until the pH value is 9, stir for 0.5 hours, let stand for 0.5 hours, separate layers, separate the water layer 0.04kg, its 2-mercapto The content of pyridine-N-oxide sodium salt was 40.2%.

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Abstract

The invention discloses a method for removing 2-mercaptopyridine-N-oxide in wastewater and recycling of the 2-mercaptopyridine-N-oxide. The method comprises the following steps: (1) mixing the wastewater containing the 2-mercaptopyridine-N-oxide and an organic solvent at a room temperature according to a ratio of (7:1) to (12:1); after stirring for 1 to 2 hours, standing for 0.5 to 1 hour; layering and separating and removing a wastewater layer; determining that the content of the 2-mercaptopyridine-N-oxide in the separated and removed wastewater layer is less than 0.05 percent; (2) at the room temperature, adding de-ionized water into the organic solvent layered by the step (1); stirring and dropwise adding a sodium hydroxide solution with the mass concentration of 30 percent until the pH value of the mixed solution is 9 to 10; continually stirring for 0.5 to 1 hour; then standing for 0.5 to 1 hour and layering. With the adoption of the method disclosed by the invention, the content of the 2-mercaptopyridine-N-oxide in the wastewater is effectively reduced, the chroma and suspended matters of the wastewater are reduced, and convenience for treating three wastes is brought.

Description

technical field [0001] The invention belongs to the field of chemistry and chemical engineering, and in particular relates to a method for removing 2-mercaptopyridine-N-oxide in waste water and its recycling. Background technique [0002] 2-Mercaptopyridine-N-oxide is slightly soluble in water, easily soluble in strong alkali, soluble in organic solvents such as halogenated hydrocarbons, aromatic hydrocarbons, ethers and esters, and is used to prepare various pyrithione salts, and pyrithione Salt is widely used as a bactericide in the fields of daily washing cosmetics and paint industry. At present, the preparation of 2-mercaptopyridine-N-oxide in industrial production generally takes 2-chloropyridine as the starting material, and it is obtained through hydrogen peroxide oxidation and mercaptolation reaction. The specific process synthesis route is as follows: [0003] [0004] In actual production, after 2-chloropyridine is oxidized and mercaptolated to obtain 2-mercapt...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/04C02F101/34C02F101/38C02F103/36
CPCC02F1/26C02F1/66C02F9/00C02F2101/34C02F2101/38C02F2101/40C02F2103/36
Inventor 梁建明孙常清张大贵颜国和
Owner 浙江丽晶化学有限公司
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