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Process for preparing hydantoin by one-step method

A hydantoin and process technology, applied in the field of one-step preparation of hydantoin, can solve problems such as lengthy route, discharge of waste acid solution, increased cost, etc., and achieve the effects of reducing cost, avoiding use, and reducing environmental pollution

Inactive Publication Date: 2005-05-18
NANJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Regardless of the high-pressure method or the normal-pressure method, the two preparation processes are two-step reactions: the first step is to synthesize hydantoin acid, and then acidify and close the ring to obtain hydantoin; this process is not only a long route, but also requires the use of a large amount of inorganic acid , which not only increases the cost, but also causes the discharge of a large amount of waste acid solution

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] Prepare 500ml of hydroxyacetonitrile solution of 4mol / L, drop it into the trickle bed reactor from the top at a flow rate of 200mL / h, carbon dioxide and ammonia gas flow from the bottom of the bed at 0.04m 3 / h and 0.02m 3 The speed of / h is passed from the bottom, the bed is heated by the jacket, and the temperature is controlled at 70°C. After the reaction solution is exhausted, the solution obtained after the reaction is collected and concentrated to 1 / 3-1 / 4 of the original volume. , cooled and crystallized to obtain hydantoin, recrystallized and vacuum dried to obtain hydantoin 138g, the purity was 99.5%, and the yield was 68.66%.

Embodiment 2

[0017] Prepare 500ml of hydroxyacetonitrile solution of 4mol / L, drop it into the trickle bed reactor from the top at a flow rate of 200mL / h, carbon dioxide and ammonia gas flow from the bottom of the bed at 0.045m 3 / h and 0.02m 3 The speed of / h is passed from the bottom, the bed is heated by the jacket, and the temperature is controlled at 70°C. After the reaction solution is exhausted, the solution obtained after the reaction is collected and concentrated to 1 / 3-1 / 4 of the original volume. , cooled and crystallized to obtain hydantoin, recrystallized and vacuum dried to obtain hydantoin 142g, the purity was 99.7%, and the yield was 70.79%.

Embodiment 3

[0019] Prepare 500ml of hydroxyacetonitrile solution of 4mol / L, drop it into the trickle bed reactor from the top at a flow rate of 200mL / h, carbon dioxide and ammonia gas flow from the bottom of the bed at 0.045m 3 / h and 0.025m 3 The speed of / h is passed from the bottom, the bed is heated by the jacket, and the temperature is controlled at 70°C. After the reaction solution is exhausted, the solution obtained after the reaction is collected and concentrated to 1 / 3-1 / 4 of the original volume. , cooled and crystallized to obtain hydantoin, recrystallized and vacuum dried to obtain hydantoin 130g, the purity was 99.2%, and the yield was 64.48%.

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Abstract

The one-step process of preparing hydantoin is that in a trickle bed reactor hydroxy methyl cyanide, CO2 and ammonia as material and solid acid as stuffing and catalyst are prepared into hydantoin through one-step process. Hydroxy methyl cyanide is made to flow into the trickle bed from the top in the flow rate of 100-300 ml / hr, CO2 and ammonia are made to flow into the trickle bed from the bottom in the flow rate of 0.01-0.1 cu m / hr and 0.005-0.06 cu m / hr separately, and through reaction at 40-120 deg.c for 2-5 hr, the reaction liquid is collected and processed through concentration, crystallization, filtering to obtain initial crystal, recrystallization and drying to obtain hydantoin. The synthesis yield may reach 74.85 %.

Description

technical field [0001] The invention relates to a technique for preparing hydantoin in a one-step method, that is, in a trickle bed reactor, hydroxyacetonitrile, carbon dioxide and ammonia are used as raw materials, and solid acid is used as a filler and a catalyst to prepare hydantoin in a one-step method. Background technique [0002] Hydantoin, also known as hydantoin, chemically named 2,4-imidazoledione, is an important chemical intermediate widely used in pharmaceutical, pesticide and chemical industries. In recent years, with the deepening of research, the demand for hydantoin in the fields of water treatment, anticorrosion and coatings has increased day by day. [0003] There are many reports on the preparation methods of hydantoin, which are mainly divided into high pressure method and normal pressure method. For example, Japanese patents report that hydantoin can be synthesized from formaldehyde, hydrogen cyanide, ammonia and ammonium carbonate under high pressure ...

Claims

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Application Information

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IPC IPC(8): C07D233/72
Inventor 韦萍周华于荣华欧阳嘉卢定强欧阳平凯
Owner NANJING UNIV OF TECH
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