Preparation method of higher safety for solid cyanamide

Abstract

The invention discloses a preparation method of higher safety for solid cyanamide. The method comprises the following steps that liquid cyanamide is driven into a crystallizer, after freezing and cooling, coarse cyanamide crystals are obtained, and the coarse cyanamide crystals are spin-dried by a centrifugal machine and then dissolved in water; after the crystals are dissolved completely, impurities in the crystals are removed by filtering equipment, filtered liquid is frozen and cooled to obtain crystals, and the crystals are separated out and dried at the low temperature to obtain the high-purity solid cyanamide; the filtered liquid flows into a dissolution kettle again for dissolving the coarse crystals and can be repeatedly used. The preparation method for the solid cyanamide has theadvantages that the technology is simple, the yield is high, the cost is low, the obtained cyanamide crystals are high in purity, and solves the problem that the solid cyanamide produced by adopting an alcohol separation method is difficult to store and transport, water as a solvent for recrystallization, and the hidden safety danger and pollution on air in the production process adopting dangerous chemicals of alcohol and the like as the solvent are eliminated.

Description

technical field [0001] The invention relates to a preparation method of solid cyanamide, in particular to a preparation method of solid cyanamide with safer process. Background technique [0002] Cyanamide, English name Cyanamide, also known as cyanamide, cyanamide, carbamamide, is a raw material for organic synthesis. Cyanamide contains cyano group and amino group, both of which are active groups. They have the multiple reactivity of the above-mentioned functional groups, and are prone to reactions such as addition, substitution, and condensation. When the purity of solid cyanamide is less than 95% and the moisture content is high, its performance is extremely unstable, and it is prone to polymerization or decomposition reactions during storage and transportation, and it may burn or explode when violent. [0003] The existing high-purity solid cyanamide production method is the alcohol analysis method, and its specific process is: high-concentration liquid cyanamide is cry...

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Problems solved by technology

[0004] The purity of the product obtained by the above method can reach more than 99%, but the organic solvent becomes a new impurity, and there are safety hazards and air pollution problems in the production process. At the same time, the product performance is still unstable, and it is prone to polymerization or Decomposition, even spontaneous combustion or explosion, resulting in unsafe products during production, storage, transportation and use

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