How to make thiourea | Lime nitrogen method has become the mainstream production process of thiourea.

Producing thiourea from lime nitrogen involves several steps and chemical reactions. Lime nitrogen typically refers to calcium cyanamide (CaNCN), which can be used as a starting material for thiourea synthesis. Here's a method for producing thiourea from calcium cyanamide:

Materials Needed: 

- Calcium cyanamide (CaNCN)

- Sulfuric acid (H₂SO₄)

- Water (H₂O)

- Hydrogen peroxide (H₂O₂)

- Distilled water

- Glassware (beakers, flasks, stirring rod)

- Heating source (hot plate or Bunsen burner)

- Filtration setup (filter paper, funnel)

- pH paper or pH meter

Procedure:

1. Hydrolysis of Calcium Cyanamide:

Dissolve calcium cyanamide (CaNCN) in water (H₂O) to form calcium hydroxide (Ca(OH)₂) and calcium cyanamide hydrolysis byproduct.

CaNCN + 3H₂O → Ca(OH)₂ + NH₄SCN

2. Formation of Thiourea:

React the ammonium thiocyanate (NH₄SCN) obtained from the hydrolysis with sulfuric acid (H₂SO₄) to form thiourea (NH₂CSNH₂).

NH₄SCN + H₂SO₄ → NH₂CSNH₂ + H₂O + NH₄HSO₄

3. Purification of Thiourea:

After the reaction, filter the mixture to separate the solid thiourea from the solution containing ammonium sulfate (NH₄HSO₄).

Wash the collected thiourea crystals with distilled water to remove any impurities.

4. Oxidation of Thiourea:

Oxidize the thiourea obtained in the previous step to form urea by treating it with hydrogen peroxide (H₂O₂).

NH₂CSNH₂ + H₂O₂ → NH₂CONH₂ + S + H₂O

5. Neutralization and Crystallization:

Neutralize the solution by adjusting the pH using a suitable base (e.g., sodium hydroxide, NaOH) until the pH reaches around 7.

Crystallize urea (NH₂CONH₂) from the solution by cooling or evaporating the solvent.

6. Separation and Drying:

Filter the urea crystals and wash them with distilled water to remove any residual impurities.

Dry the purified urea crystals either by air-drying or by using a desiccator.

7. Collection and Storage:

Once dried, collect the urea product and store it in a clean, dry container for further use.

This process involves multiple chemical reactions and purification steps to obtain thiourea from calcium cyanamide. It's crucial to handle chemicals safely and conduct reactions in a well-ventilated laboratory environment. Additionally, precise control of reaction conditions and proper purification techniques are necessary to obtain high-purity thiourea.

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Sinhon Chemical focuses on high-quality thiourea production and manufacturing.  The thiourea we produce has high purity, good quality and stable product performance. The annual production capacity is 20,000 tons, the inventory is sufficient, and the supply is stable. We also trade other products, such as molecular sieves, silica gel desiccant, aniline, methylene chloride, chloroform, sodium hydroxide, propylene oxide, etc. 

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