Method and device for directly synthesizing oxamide granules

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...

AI Technical Summary

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 materials used were oxalic acid diester and its corresponding low-chain fatty alcohol, and discussed different reactions The purity and yield of the oxamide product obtained under certain conditions, the reaction process in the patent is only used for laboratory research, and the dosage is small. At the same time, the ammonolysis process is only briefly discussed and its control related factors. Public, it is not known whether it has been industrialized

[0006] So far, there is no report on the preparation of oxamide by the direct aminolysis reaction of dimethyl oxalate and the control of its particle formation, and there is no report on the integration of ammonolysis reaction and particle formation equipment

Images