Method and device for directly synthesizing oxamide granules

A technology of oxamide and granules, which is applied in the preparation of carboxylic acid amide, chemical instruments and methods, and the preparation of organic compounds, etc., which can solve the problem that there is no integrated equipment for ammonolysis reaction and granule forming, and the key technology has not been directly disclosed and has not been industrialized. Application and other issues, to achieve the effect of saving equipment investment and energy consumption, large economic benefits and application prospects, and expanding market share

Inactive Publication Date: 2013-08-14
TIANJIN UNIV
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  • Summary
  • Abstract
  • Description
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Problems solved by technology

The method for synthesizing oxamide with hydrocyanic acid as a raw material is not high due to the high cost of hydrocyanic acid, but the yield and purity of the product are not high, and at the same time, the whole process causes great pollution to the environment, so this method does not get industrial application
Pyrolysis of ammonium oxalate or urea oxalate produces oxamide, with a yield of less than 50%, and the cost of pyrolysis raw materials is high, and there is no large-scale application
At the beginning of the 21st century, Japan's Tomohiko Yamamoto et al first disclosed the research on the preparation of oxalamide by aminolysis of oxalic acid diester in U.S. Patent US6348626. The raw materia

Method used

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  • Method and device for directly synthesizing oxamide granules

Examples

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Effect test

example 1

[0045] As shown in the accompanying drawings of the description, first configure a certain concentration of ammonia methanol solution according to the first step of the implementation mode, control the temperature of the front ammonia absorption tank 7 to 5°C, and start to pass ammonia, and the ammonia flow rate should not be too high quick. Add raw material dimethyl oxalate in the reaction kettle 4 in the process of feeding ammonia gas, after the ammonia gas is passed into, open the pre-ammonia gas absorption tank infusion regulating valve 9, open the refrigeration unit 5 of the reaction kettle simultaneously, the ammonia gas During the addition of the methanol solution, no stirring was performed. Select the mass ratio of methanol to dimethyl oxalate to be 4:1 for addition, and the ammonia gas is excessive. After the addition was completed, the temperature began to rise, and the reaction kettle temperature regulating device 2 was opened to set the reaction temperature to 50°...

example 2

[0047] The operation steps of the whole reaction process are the same as Example 1, and the conditions of the reaction process are changed as follows: the mass ratio of methanol to dimethyl oxalate is 2:1, the reaction temperature is 20°C, the reaction time is 1h, and the yield of oxamide is 13.23 %, the purity is 49.33%, and the total organic nitrogen content is 15.69%. Due to the low yield and purity of the obtained product, no particle molding treatment is carried out.

example 3

[0049] The operation steps of the whole reaction process are the same as in Example 1, and the conditions for changing the reaction process are: the mass ratio of methanol to dimethyl oxalate is 2:1, the reaction temperature is 60°C, and the reaction time is 1h. The particle forming process and conditions are the same as in Example 1 Described, the yield that finally obtains oxamide is 97.49%, and purity is 98.34%, and total organic nitrogen content is 31.27%, and the average particle diameter of oxamide solid particle is 3.89mm, and crushing strength is 2.8Kg / particle, in water two No collapse phenomenon was found in the week, and it has good stability in water.

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Abstract

The invention relates to a method and a device for directly synthesizing oxamide granules. Dimethyl oxalate and ammonia serving as reaction raw materials and methanol serving as a reaction solvent are subjected to an ammonolysis reaction under normal pressure, a stirring system and a cooling system are arranged in the reactor, a jacket temperature control device is arranged at the outer side of the reactor, and a condenser is connected to the upper part of the reactor for regulation. A front ammonia absorption tank is arranged at the front end of the reactor, the front end of the reactor is provided with a cooling system, the outlet of the condenser is respectively connected with the front ammonia absorption tank and the tail gas absorption tank. The reaction process and the granule forming process can be performed in the same reactor, the methanol recycling and tail absorption device are equipped, and the ammonia gas is not discharged into atmosphere. The reaction investment and consumption can be greatly saved, the environmental pollution is reduced, and the product can be produced in a large scale until the product is industrially applied, so that the urea and ammonium bicarbonate are replaced, and the occupancy of oxamide in the nitrogenous fertilizer market is increased.

Description

technical field [0001] The invention belongs to the technical field of chemical industry, chemical fertilizer and environmental protection. It involves the whole integrated process of using dimethyl oxalate and ammonia gas as raw materials and methanol as a reaction solvent to synthesize oxamide as a solid product by ammonolysis under normal pressure and forming oxamide solid particles. Background technique [0002] Oxamide (Oxamide) also known as oxalamide, chemical formula (CONH 2 ) 2 , is a slow-acting nitrogen fertilizer with high nitrogen content, the theoretical nitrogen content is 31.8%. Its solubility in soil water is 0.016%, and it decomposes slowly. After being applied in farmland, it is not easy to be lost along with the water body, which can reduce the air and water pollution caused by nitrogen loss. At the same time, oxamide can be used as a decelerating agent in rocket propellants, as a gas generating agent and cooling agent in gas generating agents, as a s...

Claims

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Application Information

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IPC IPC(8): C07C233/56C07C231/02C05C11/00
Inventor 杨长生曾浩
Owner TIANJIN UNIV
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