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Production technology for synthesizing thiourea by urea method

A technology of thiourea and urea, applied in the direction of organic chemistry, can solve the problems of serious pollution, high pollution, high energy consumption, etc., and achieve the effect of high product yield and high purity

Active Publication Date: 2012-09-05
SHANDONG EFIRM BIOCHEMISTRY & ENVIRONMENTAL PROTECTION CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0013] The development of this process is relatively mature. At present, domestic manufacturers use this method to generate cyanamide. However, because the production of raw material lime nitrogen is a traditional industry with high energy consumption, high pollution and high emissions, it is also the source of pollution in deep processing production.
At the same time, the production of calcium carbide not only produces a large amount of smoke and dust, but also a large amount of available waste heat is discharged with the smoke and dust, which pollutes the environment and wastes resources. The production cost is high, the investment in equipment is large, the pollution is serious, and the process control requirements are strict.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] The technical scheme involved in the invention is described in detail by using calcium oxide as a catalyzed urea to prepare thiourea and taking 10-ton reaction equipment as an example.

[0039] The industrial grade urea and the industrial grade calcium oxide are added into the heating pulverizing mixer at a weight ratio of 5:1, pretreated at 130°C-150°C for 60 minutes, pulverized and mixed evenly. The by-product ammonia gas is absorbed by water, pumped into the liquid ammonia rectification tower to produce liquid ammonia.

[0040] Put 6.6 tons of the pretreated material into the ammonia release sintering furnace and react at 350-400°C for 3 hours to produce a material mainly composed of calcium cyanate. The by-product ammonia gas is absorbed by water, pumped into the liquid ammonia rectification tower to produce liquid ammonia.

[0041] Put the calcium cyanate-based material produced by the first heating reaction into a high-temperature calcination furnace, and carry o...

Embodiment 2

[0046] Taking the preparation of thiourea from urea catalyzed by potassium oxide and the 10-ton reaction equipment as examples, the technical solution involved in the invention is described in detail.

[0047] The industrial-grade urea and industrial-grade potassium oxide weighed in a weight ratio of 3:1 are added to a heating pulverizer, pretreated at 160° C.-180° C. for 10 minutes, pulverized and mixed uniformly. The by-product ammonia gas is absorbed by water, pumped into the liquid ammonia rectification tower to produce liquid ammonia.

[0048] Put 6.5 tons of pretreated materials into the ammonia release sintering furnace, and react at 300-350°C for 1 hour. The main reaction product is potassium cyanate, which condenses into a hard solid substance. The by-product ammonia gas is absorbed by water, pumped into the liquid ammonia rectification tower to produce liquid ammonia.

[0049] Put the potassium cyanate-based material produced through the first heating reaction into a...

Embodiment 3

[0054] Using the mixed system of sodium oxide, barium oxide and magnesium oxide as catalyst to prepare thiourea from urea, and taking 10-ton reaction equipment as an example, the technical scheme involved in the invention is described in detail.

[0055] Use reagent-grade oxides to prepare mixed catalysts in the ratio of sodium oxide, barium oxide and magnesium oxide in a ratio of 1:1:1. High-purity grade urea and mixed catalysts are added to the heating pulverizer in a weight ratio of 8:1. Pretreatment at -160°C for 30 minutes, pulverized and mixed evenly. The by-product ammonia gas is absorbed by water, pumped into the liquid ammonia rectification tower to produce liquid ammonia.

[0056] Put 6.6 tons of the pretreated material into the ammonia release sintering furnace, react at 200-250°C for 8 hours, and generate a material mainly composed of mixed cyanate. The by-product ammonia gas is absorbed by water, pumped into the liquid ammonia rectification tower to produce liqui...

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Abstract

The invention relates to an industrial production technology for synthesizing thiourea by a urea method, which uses urea as a starting material to synthesize the thiourea by two steps of high temperature calcining. In hot environment, the urea generates cyanate and releases ammonia under the action of alkali metals or alkaline earth metal oxides; the cyanate is converted to cyanogen ammonium saltat high temperature; H2S is directly pumped into suspension of the cyanogen ammonium salt to react to synthesize the thiourea and simultaneously produce a byproduct metal hydroxide. The ammonia generated in the synthesis process is absorbed by water for producing liquid ammonia; the metal oxide obtained by dehydrating the byproduct metal hydroxide is reused. The industrial production technology of the invention has low requirements on the raw materials, is widely applicable to the raw materials of different grades, has high product yield and purity, generates no industrial waste gas and waste residues and belongs to the green environmental protection process.

Description

[0001] 1. Field [0002] The invention belongs to the technical field of chemical industry and relates to the synthesis technology of thiourea, in particular to the industrialized production technology of synthesizing thiourea by urea method. 2. Background technology: [0003] Thiourea【CS(NH 2 ) 2 】It is an important raw material for organic synthesis. White shiny orthorhombic granular crystal with bitter taste. The melting point is 176~178°C, and the relative density is 1.405 (20°C). The solubility in water is 5.19% at 6°C, and 14.07% at 20°C. It is soluble in ethanol when heated, slightly soluble in ether, and is easy to deliquescence in air. Mainly used as raw materials for pharmaceuticals (sulfathiazole, methionine, pipemidic acid and fat pig slices), dyes, resins, compressed powders, etc.; also used as vulcanization accelerators for rubber, flotation agents for metal minerals, etc.; photography Developer and toner on materials; metal antirust agent and electroplating...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C335/02
Inventor 马韵升史庆苓郑亭路张建林吴志红曹永芳史鹏韩百涛
Owner SHANDONG EFIRM BIOCHEMISTRY & ENVIRONMENTAL PROTECTION CO LTD