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A kind of preparation method of biurea

A technology of biurea and solution, applied in the direction of organic chemistry, etc., can solve the problems of low purity of biurea, long reaction process, high cost, etc., and achieve the effect of reducing the treatment process and treatment cost, long treatment cycle and improving quality

Active Publication Date: 2017-12-19
QINGHAI SALT LAKE IND
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0014] The purpose of the present invention is to provide a preparation method of biurea, which is used to solve the problem of long reaction process, high energy consumption and high cost in the acid condensation reaction and weak base condensation reaction in the existing preparation method of biurea. The problem of low purity of the produced biurea

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  • A kind of preparation method of biurea
  • A kind of preparation method of biurea
  • A kind of preparation method of biurea

Examples

Experimental program
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Effect test

Embodiment 1

[0047] This embodiment provides a preparation method of biurea, comprising the following steps:

[0048] Step 1: Prepare 20% to 25% hydrazine hydrate solution

[0049] a. The crude hydrazine hydrate solution obtained by the traditional urea method is sampled and analyzed to determine the contents of sodium hydroxide and sodium carbonate in the crude hydrazine hydrate solution respectively, and according to the reaction equation of sodium hydroxide and calcium chloride and sodium carbonate and chlorine The reaction equation of calcium chloride calculates the total mass m of calcium chloride needed to react with sodium hydroxide and sodium carbonate;

[0050] b. input the crude hydrazine hydrate solution into the first stage mixing kettle, and continue to add calcium chloride solid in the first stage mixing kettle, the quality of the added calcium chloride solid is 95% of the total mass m of calcium chloride , the first-stage mixing tank is a mixing tank with a stirrer, the cru...

Embodiment 2

[0064] Prepare biurea according to the steps in Example 1, but add the urea solution according to the following process in step 2: the first section is to add 60% of the total amount of urea solution to the condensation kettle, and the control time is 6h Complete; the second stage is to add 30% of the total amount of urea solution, and the control is completed within 10 hours; the third stage is to add 10% of the total amount of urea solution, and the control time is 6 hours to complete, and the interval between the first stage and the second stage is 2 minutes , the interval between the second section and the third section is 2min.

[0065]After continuing to react for 1 hour through step 3, the concentration of residual hydrazine hydrate in the reaction solution in the condensation tank was sampled and analyzed. After testing, it was 0.92 g / L, and the concentration of residual urea in the reaction solution was 2.57 g / L.

Embodiment 3

[0067] Prepare biurea according to the steps in Example 1, but add the urea solution according to the following process in step 2: the first section is to add 60% of the total amount of urea solution to the condensation kettle, and the control time is 9h Complete; the second stage is to add 30% of the total amount of urea solution, and the control time is 10h to complete; the third stage is to add 10% of the total urea solution, and the control time is 1h to complete, the interval between the first stage and the second stage 0.5min, the interval between the second section and the third section is 1min.

[0068] After continuing to react for 1 hour through step 3, the concentration of residual hydrazine hydrate in the reaction solution in the condensation tank was sampled and analyzed. After testing, it was 0.81g / L, and the concentration of residual urea in the reaction solution was 2.37g / L.

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Abstract

The invention discloses a preparation method of biurea, wherein the preparation method comprises the steps: firstly, preparing a 20%-25% hydrazine hydrate solution as a raw material; followed by, adding a urea solution into a condensation kettle in a successive subsection manner, and carrying out condensation reaction, wherein the mass ratio of hydrazine hydrate to urea is less than or equal to 1:2.55, and the addition way of the urea solution is divided into three sections; after addition of urea is completed, continuing to carry out reaction for a period of time until the concentration of residual hydrazine hydrate in a reaction liquid in the condensation kettle is less than or equal to 1 g / L, stopping heating of the condensation kettle, and then adding water to dissolve sodium chloride precipitated in the condensation reaction process; and cooling, and then successively carrying out discharging, solid-liquid separation, and washing and drying treatment to obtain the diurea product. The preparation method of the diurea makes the preparation process of the diurea more energy saving and more efficient and makes the cost lower, impurities in the prepared diurea are fewer, and the purity is higher.

Description

technical field [0001] The invention relates to a preparation method of biurea, in particular to a preparation method for producing biurea by compressing and compressing a hydrazine hydrate solution containing high-concentration sodium chloride. Background technique [0002] Biurea, the chemical formula is C 2 h 6 N 4 o 2 , mainly used in the production of ADC blowing agent, the demand is very large. Biurea is usually prepared by condensation reaction of hydrazine hydrate and urea as raw materials. [0003] Hydrazine hydrate, also known as hydrazine hydrate, has the chemical formula N 2 h 4 ·H 2 O, the synthesis method commonly used in China is the urea method, and the reaction equation is: [0004] NH 2 CONH 2 +NaClO+2NaOH→N 2 h 4 ·H 2 O+NaCl+Na 2 CO 3 , [0005] Owing to can contain sodium carbonate, sodium chloride and a small amount of sodium hydroxide in the reaction product hydrazine hydrate, so reaction product is thick hydrazine hydrate. For the reac...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C281/06
CPCC07C281/06
Inventor 刘利德向元瑜宁鹏李存善于雪峰俞莅军孙学敏刘林俊董永雷青
Owner QINGHAI SALT LAKE IND
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