Process for producing thiourea dioxide

A technology for thiourea dioxide and thiourea dioxide, applied in the direction of organic chemistry, can solve the problems of reduced purity, large solvent loss, low purity, etc., and achieve the effects of overcoming small crystal particle size, improving crystalline state and simple production process

Inactive Publication Date: 2003-10-15
陶华西
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The preparation method of existing thiourea dioxide mainly contains two kinds: a kind of is non-aqueous solvent method: namely add chlorinated hydrocarbons such as carbon tetrachloride, 1-2-dichloroethane, trichloromethane and methyl alcohol, ethanol in the reactor , acetone and other fatty alcohols or ketones, and then add thiourea and hydrogen peroxide, because the reaction product is insoluble in the solvent, so the yield is higher, but because the reaction between thiourea and hydrogen peroxide is not a homogeneous reaction, there are many by-products And it is insoluble in solvent and mixed into the product, which reduces the purity, and at the same time, the large loss of solvent also causes high cost and cannot realize industrial production
The other is the water solvent method: thiourea is dissolved in water first, then hydrogen peroxide is added dropwise for reaction, and thiourea dioxide is obtained by filtration and drying. This method can dissolve thiourea in water to form a homogeneous phase, and the reaction speed is fast. , less by-products, but due to the influence of control conditions, additives and other factors, the product has poor crystallization, low purity and poor stability

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] Add 2.0 g of 30% sodium polyacrylate as a crystal habit modifier to 800 g of deionized water, and stir thoroughly to prepare an aqueous solution containing the crystal habit modifier for later use.

[0016] Take 358g of 50% hydrogen peroxide solution, add 1g of trisodium citrate and 2.5g of 50% ATMP, stir thoroughly to dissolve, and prepare a stabilizer-containing hydrogen peroxide solution for later use.

[0017] Weigh 200g of thiourea and appropriate amount of baking soda or ammonium bicarbonate for later use.

[0018] Add the aqueous solution to a 2000ml jacketed and stirred reaction kettle, first put 40g of thiourea and stir fully to dissolve it, open the freezing valve, pass in frozen brine at -15°C, cool to about 0°C, and start dripping 50% hydrogen peroxide solution containing stabilizer, the temperature is controlled at 0~5℃, the stirring speed is 100 rpm, the PH value is controlled at 3~5, when it is lower than 3, use baking soda or ammonium bicarbonate to adjust t...

Embodiment 2

[0021] Add 2.0 g of 30% sodium polyacrylate and 1.0 g of polyacrylic acid to 800 g of deionized water, and stir thoroughly to prepare an aqueous solution containing crystal habit modifier for later use.

[0022] Take 500 g of 35% hydrogen peroxide solution and add 2.5 g of 50% ATMP, stir thoroughly and prepare a stabilizer-containing hydrogen peroxide solution for later use.

[0023] Weigh 200g of thiourea and appropriate amount of baking soda or ammonium bicarbonate for later use.

[0024] The following operation steps are the same as in Example 1, and finally 228.5 g of thiourea dioxide crystal powder is obtained, and the yield is 80.3%.

Embodiment 3

[0026] Add 2.0 g of 30% polymaleic acid to 800 g of deionized water, and stir thoroughly to prepare an aqueous solution containing crystal habit improver for later use.

[0027] Take 358 g of 50% hydrogen peroxide solution, dissolve in 1 g of trisodium citrate, and stir thoroughly to prepare a stabilizer-containing hydrogen peroxide solution for later use.

[0028] Weigh 200g of thiourea and appropriate amount of baking soda or ammonium bicarbonate for later use.

[0029] The following operation steps are the same as in Example 1, except that 25 g of thiourea is added at regular intervals. After the injection is completed in 8 batches, 231.6 g of thiourea dioxide crystal powder is finally obtained, and the yield is 81.4%.

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PUM

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Abstract

The present invention belongs to the field of peroxide preparing technology in organic chemistry. Into reactor, water is added in advance, thiourea is thrown in batches and hydrogen peroxide solution containing stabilizer is dripped to produce thiourea dioxide. After finishing the reaction, thiourea dioxide is filtered and stoved to obtain crystallized thiourea dioxide powder. The added amountof the stabilizer is 0.1-5 wt% of thiourea and crystal habit modifier in 0..005-2 wt% of thiourea may be also added into water. The improved thiourea dioxide producing process has improved crystal state of thiourea dioxide and raised product purity and is suitable for industrial production in large scale.

Description

Technical field [0001] The invention relates to a preparation method of thiourea dioxide, belonging to the technical field of peroxide preparation in organic chemistry. Background technique [0002] Thiourea dioxide, its molecular formula is CH 4 N 2 O 2 S, white crystalline powder. Thiourea dioxide is a new type of reducing agent with strong reducing ability, good stability, safer transportation and storage. It is not only widely used in the printing and dyeing industry to replace the insurance powder, but also in the bleaching of wool and paper pulp, as a photosensitizer for photographic and copying materials. Molecular synthesis, fiber and resin catalysts, detergents and treatment of three wastes have a wide range of uses. [0003] There are two main methods for preparing thiourea dioxide: one is the non-aqueous solvent method: that is, adding carbon tetrachloride, 1-2-dichloroethane, trichloromethane and other chlorinated hydrocarbons, methanol, and ethan...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C335/04C07C381/00
Inventor 陶华西郑龙罗力军杨国南
Owner 陶华西
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