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Process for producing thiourea dioxide

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

Inactive Publication Date: 2005-03-16
陶华西
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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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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  • Process for producing thiourea dioxide

Examples

Experimental program
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Effect test

Embodiment 1

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

[0016] Get 358g of 50% hydrogen peroxide solution, add 1g of trisodium citrate and 2.5g of 50% ATMP, after fully stirring and dissolving, make hydrogen peroxide solution containing stabilizer for subsequent use.

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

[0018] Add the aqueous solution into a 2000ml jacketed and stirring reaction kettle, first put 40g of thiourea into it and stir thoroughly to dissolve it completely, open the freezing valve, pour in frozen brine at -15°C, cool down to about 0°C, and start adding dropwise 50% hydrogen peroxide solution containing stabilizer, the temperature is controlled at 0-5°C, the stirring speed is 100 rpm, the pH value is controlled at 3-5, if it is lower than 3...

Embodiment 2

[0022] Add 2.0 g of 30% sodium polyacrylate and 1.0 g of polyacrylic acid into 800 g of deionized water, and stir well to prepare an aqueous solution containing a crystal habit modifier for future use.

[0023] Get 500g of 35% hydrogen peroxide solution and add 2.5g of 50% ATMP, stir well and make hydrogen peroxide solution containing stabilizer for subsequent use.

[0024] Weigh 200g of thiourea, appropriate amount of baking soda or ammonium bicarbonate for later use.

[0025] The following operation steps are the same as in Example 1, and 228.5 g of thiourea dioxide crystalline powder are finally obtained, with a yield of 80.3%.

Embodiment 3

[0027] Add 2.0 g of 30% polymaleic acid into 800 g of deionized water, stir well and make an aqueous solution containing the crystal habit modifier for later use.

[0028] Get 358g of 50% hydrogen peroxide solution, dissolve in 1g of trisodium citrate, stir well and make hydrogen peroxide solution containing stabilizer for subsequent use.

[0029] Weigh 200g of thiourea, appropriate amount of baking soda or ammonium bicarbonate for later use.

[0030] The following operation steps are the same as in Example 1, except that 25g of thiourea is dropped into at regular intervals. After 8 times of throwing, finally 231.6g of thiourea dioxide crystalline powder is obtained, and the yield is 81.4%.

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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 amount of 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, which belongs 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, which has strong reducing ability, good stability, and relatively safe transportation and storage. It is not only widely used in the printing and dyeing industry to replace hydrosulfite, but also used in wool and pulp bleaching, photosensitizers for photography and copying materials, high It is widely used in molecular synthesis, fiber and resin catalyst, detergent and treatment of three wastes. [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, trichlorom...

Claims

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Application Information

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