Riel Know：Thiourea - Basic knowledge and application areas

Riel Know —— A chemical encyclopedia column from Riel Chemical.

Thiourea - Basic knowledge and application areas

Basic Information:

Name:  Thiourea / TU
Chinese Name:  硫脲 (Liu Niao)
Cas: 62-56-6
UNII: GYV9AM2QAG
Chemical formula: SC(NH2)2
Molecular formula: CH4N2S
Molar mass: 76.12 g · mole −1
Appearance: White solid
Density: 1.405 g/ml
Melting point: 182 degrees Celsius (360 degrees Fahrenheit; 455 Kelvin)
Water soluble: 142 g/L (25 ° C)
Magnetic susceptibility (χ) : −4.24 × 10 −5 cubic centimeters/mole

Thiourea is an organosulfur compound with the molecular formula SC (NH 2) 2 and the structure H 2 N−C(=S)−NH 2. Its structure is similar to urea (H 2 N−C(=O)−NH 2), except that the oxygen atom is replaced by a sulfur atom (as implied by the thioprefix); However, the properties of urea and thiourea are quite different. Thiourea is an organic synthesis reagent. Thiourea is a broad class of compounds with a universal structure R 2 N−C(=S)−NR 2.

Riel Chemical Thiourea

As an enterprise focusing on the production of chemical raw materials, Riel Chemicals began to be involved in the production of Thiourea (TU) as early as the end of the 20th century. Through continuous technology research and development and equipment upgrading, the company has made breakthroughs in thiourea production process, product quality and capacity. At present, Riel Chemicals has become one of the leading companies in the production of thiourea in the world, providing high-quality thiourea products to a variety of industries.

Key attributes

Products: Thiourea ≥99% , CS ( NH₂) ₂，belongs dangerous chemical.

Physical and chemical properties:

Appearance: white crystal powder; Density: 1.405; Molecular weight: 76.12

Melting point: 171-175℃; Boiling point: 349 to 352°F (NTP, 1992).

Packing: 25kg or 25kg/bag

Production standard

CAS: 62-56-6

Products meets GB/8218-2018：

References: Riel Chemical Lab1&2, National public service platform for standards information.

Riel chemical thiourea production process

Riel Chemical adopts advanced chemical synthesis process and takes environmental protection and high efficiency as the core principle to ensure the green and low carbon emission of thiourea production process.

1. Selection of raw materials
Main raw materials:
  Industrial grade Calcium Cyanamide (CaCN₂)
  Hydrogen Sulfide (H₂S) or Ammonium Sulfate (NH₄)₂SO₄
  Raw materials are rigorously screened and purified to ensure reaction stability and high purity (≥99%) of the final product.
2. Production process
  Thiourea production is divided into the following key steps:
a. Cyanamine reaction:
  Calcium cyanamide (H₂NCN) is formed by hydrolysis reaction.
  Reaction equation:  CaCN₂ + 3H₂O → Ca(OH)₂ + H₂NCN
b. Vulcanization reaction:
  Cyanamide reacts with hydrogen sulfide or ammonium sulfate to form thiourea.
  Reaction equation (taking hydrogen sulfide as an example) : H₂NCN + H₂S → SC(NH₂)₂
c. Product purification and drying:
  After the reaction, the mixture was filtered, washed and dried to obtain white crystalline thiourea with high purity.

Technology and equipment used

Riel Chemical uses industry-leading production technology and modern equipment to ensure the efficiency and stability of the production process.

1. Technology
Continuous production technology: the automatic operation of reaction, separation, purification and drying is realized, and the production capacity and product consistency are improved.

Green chemical technology: the waste gas recovery device was applied to reduce the emission of hydrogen sulfide and achieve environmentally friendly production.
Process optimization: Through precise control of reaction conditions (temperature, pressure, catalyst, etc.), improve reaction conversion rate and product yield.

2: Equipment
Reactor: high temperature and high pressure stainless steel reactor, suitable for continuous reaction and mass production.
Separation and purification equipment: centrifugal separator and multi-stage filtration system to ensure product purity.
Drying equipment: Vacuum dryer is used to protect the physical characteristics of thiourea and prevent thermal decomposition.
Exhaust gas treatment system: includes absorption tower and catalytic unit to recover hydrogen sulfide and reduce environmental impact.

Production capacity and output

Global thiourea production is about 10,000 tons per year. About 40% are produced in Germany and 20% in Japan. The remaining 40 percent is made in China. At present, the market share of thiourea produced by Riel Chemical has reached 61% in China.

Annual output：

Riel Chemicals currently has an annual production capacity of 20,000 tons of thiourea, which can meet the needs of global customers in a variety of fields.

Capacity expansion:

The company plans to increase its production capacity to 30,000 tons in the next three years to meet the growth of market demand.

Field of application

1. Metal plating: used for plating and surface treatment of copper, silver, gold and other metals.
2. Mineral refining: as a key reagent for ore refining and precious metal refining.
3. Chemical catalyst: used in the catalytic process of chemical reaction.
4. Dye and rubber: used in dye production and rubber vulcanization process.
5. Medicine and pesticides: as an important ingredient of pharmaceutical intermediates and pesticide raw materials.

In terms of thiourea production, Riel Chemical continues to explore more environmentally friendly and economical production technologies, and actively develops new products to meet the needs of different markets. In the future, Riel Chemical will provide global customers with better quality thiourea products with more efficient and greener production processes, and contribute to the sustainable development of the chemical industry.

Author: Riel chemical.           Edited July 7, 2023.