A kind of method prolonging the shelf-life of thiourea dioxide product

A technology of thiourea dioxide and shelf life, applied in organic chemistry and other directions, can solve the problems of difficult temperature control of reaction system, uneven particle size distribution, uneven local supersaturation, etc., to avoid simultaneous crystallization, improve mother liquor occlusion phenomenon, prolong The effect of product shelf life

Inactive Publication Date: 2016-04-20
WUHAN UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since the reaction rate of hydrogen peroxide oxidizing thiourea in the water phase is very fast and the heat of reaction is very large, the temperature of the reaction system is difficult to control, resulting in a fast reaction crystallization rate of thiourea dioxide and uneven local supersaturation. The crystal particle size of thiourea dioxide product is small, the particle size distribution is uneven, the crystal surface is rough, and it is easy to coalesce and contain the crystallization mother liquor, so that the residual reaction raw materials (hydrogen peroxide, thiourea) and side reaction impurities in thiourea dioxide product are relatively high.
The thiourea dioxide product with small particle size, uneven distribution and rough surface has a large specific surface area, which makes it easier to absorb moisture, while the residual hydrogen peroxide and thiourea in the product will undergo deep oxidation in the presence of water, and the large amount of heat generated by the reaction will also Decompose thiourea dioxide to generate sulfur, which makes the product prone to yellowing and quality degradation during storage and transportation.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] A method for prolonging the shelf life of thiourea dioxide products, the specific steps are: at 0-10°C and at a rotational speed of 300-400r / min, first prepare a thiourea dioxide aqueous solution with a concentration of 1-3wt%; Add crystal seeds, heat and stir to grow crystals for 15-30 minutes to obtain a suspended crystal slurry; then add a solvent to the suspended crystal slurry, filter, wash, and dry the filter cake under reduced pressure at 40-50°C to obtain sulfur dioxide Urea crystals.

[0018] The seed crystals refer to thiourea dioxide crystals, and the seed crystals are added in an amount of 0.1-3wt% of the total amount of thiourea dioxide crystal products.

[0019] The eluting agent is methanol, and the amount of the eluting agent added is 3 to 4 times of the amount of water used when preparing the thiourea dioxide aqueous solution, and the feeding time of the eluting agent is 3 to 4 hours.

[0020] The thiourea dioxide product obtained in this example meets...

Embodiment 2

[0022] A method for prolonging the shelf life of thiourea dioxide products, the specific steps are: at 10-20°C and at a speed of 400-500r / min, first prepare a thiourea dioxide aqueous solution with a concentration of 2-4wt%; Add crystal seeds, heat and stir to grow crystals for 15-30 minutes to obtain a suspended crystal slurry; then add a solvent to the suspended crystal slurry, filter, wash, and dry the filter cake under reduced pressure at 40-50°C to obtain sulfur dioxide Urea crystals.

[0023] The seed crystals refer to thiourea dioxide crystals, and the amount of seed crystals added is 1-4 wt% of the total amount of thiourea dioxide crystal products.

[0024] The dissolving agent is ethanol, and the amount of the dissolving agent added is 4 to 5 times of the amount of water used when preparing the thiourea dioxide aqueous solution, and the feeding time of the dissolving agent is 3.5 to 4.5 hours.

[0025] The thiourea dioxide product obtained in this example meets the h...

Embodiment 3

[0027] A method for prolonging the shelf life of thiourea dioxide products, the specific steps of which are as follows: at 20-30°C and at a rotational speed of 500-600r / min, first prepare a thiourea dioxide aqueous solution with a concentration of 3-5wt%; Add crystal seeds, heat and stir to grow crystals for 15-30 minutes to obtain a suspended crystal slurry; then add a solvent to the suspended crystal slurry, filter, wash, and dry the filter cake under reduced pressure at 40-50°C to obtain sulfur dioxide Urea crystals.

[0028] The seed crystals refer to thiourea dioxide crystals, and the amount of seed crystals added is 2-5 wt% of the total amount of thiourea dioxide crystal products.

[0029] The eluting agent is isopropanol, the amount of the eluting agent added is 4 to 5 times of the amount of water used when preparing the thiourea dioxide aqueous solution, and the feeding time of the eluting agent is 4 to 5 hours.

[0030] The thiourea dioxide product obtained in this e...

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PUM

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Abstract

The invention specifically relates to a method for prolonging the shelf life of thiourea dioxide products. The technical plan is: under the conditions of 0~30°C and 300~600r / min rotating speed, add crystal seeds to the saturated aqueous solution of thiourea dioxide, grow the crystals, and obtain a suspended crystal slurry; then add and dissolve the suspended crystal slurry Analyzing agent, elution crystallization, filtration and drying to obtain thiourea dioxide crystals, the crystal product meets HG? High stability requirements in the 3258-2010-T industrial thiourea dioxide standard, and its thermal stability ≥ 60min. The thiourea dioxide crystal product produced by the invention has the advantages of concentrated particle size distribution, crystalline luster on the surface, high purity, good thermal stability, etc., can effectively improve the quality of the thiourea dioxide product, improve the safety performance of its transportation and storage, and prolong the shelf life of its product.

Description

technical field [0001] The invention belongs to the technical field of industrial crystallization, and in particular relates to a method for extending the shelf life of thiourea dioxide products. Background technique [0002] Thioureadioxide (TD for short) is a new, environmentally friendly and powerful reducing agent that can replace sodium hydrosulfite. Its reducing ability is 5 times that of hydrosulfite, and it has non-toxic, tasteless, good stability, safe transportation, and high reduction potential. Advantages, it is widely used in textile, paper, photosensitive materials, cosmetics and other industrial fields. In recent years, its application in organic synthesis and analysis, medicine, spices and precious metal recovery and separation has also been continuously developed. At present, the annual demand for thiourea dioxide is about 200,000 tons. Although the production scale of my country's thiourea dioxide enterprises (accounting for about 70% of the world's total ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C381/14
Inventor 张春桃刘帮禹王鑫王海蓉
Owner WUHAN UNIV OF SCI & TECH
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