How Is Carbon Disulfide Manufactured? Step-by-Step Process & Reactions
Sulphide is a sulphur inorganic anion with the chemical formula S-2, as well as a compound having one or more S-2 ions. Sulphide salt solutions are corrosive. Large families of inorganic and organic substances, such as lead sulphide and dimethyl sulphide, are classified as sulphides. The conjugate acids of sulphide are hydrogen sulphide (H2S) and bisulfide (SH).
Carbon disulfide was first prepared by a German chemist named Wilhelm August Lampadius in 1796. When pyrite was heated with moist charcoal carbon disulfide was formed, which he first called “Liquid Sulphur”. Then the composition was later found out by several other chemists.
What is Carbon Disulfide?
Carbon disulfide is a neurotoxic and colourless organic compound that is volatile in nature. Small amounts of carbon disulfide are released into the atmosphere during volcanic eruptions and marshes. It can also be manufactured by combining carbon and sulfur at high temperatures. The reaction would be:
C + 2S →CS2
Formula of Carbon Disulphide
CS2 is the formula for carbon disulfide. It can also be called Dithio Methane, Carbon bisulfide, Carbon sulphide, Sulfo Carbonic anhydride and Dithiocarbamic anhydride. This compound is frequently used in the field of organic chemistry and industries.
For the production of rayon fibre, about 13% of carbon disulfide is consumed in India. Carbon disulfide is used as a solvent for the production of selenium, bromine, iodine, rubber, fats, resins, and phosphorus. It is also used in the purification process of single tubed carbon nanotubes.
More concepts of carbon disulfide formula are discussed in this article.
Properties of Carbon Disulfide
Physical Properties:
The chemical formula for carbon disulfide is CS2 where the molecular weight is said to be 76.14 g mol-1.
Pure and impure carbon disulfide occurs in the form of a colourless liquid and yellowish respectively. It is not easily soluble in water.
Carbon disulfide is highly flammable and can evaporate rapidly at room temperature.
Pure carbon disulfide odour is similar to the sweet and pleasant smell of chloroform. Whereas the commercial grades of CS2 give a foul odour that smells like rotten eggs.
Carbon disulfide structure is linear in nature.
Chemical Properties:
The vapour pressure of carbon disulfide at 25oC is 352.6 mm Hg.
The boiling point of CS2 is 46.24 celsius.
The melting point of CS2 is -111.61oC.
The density of CS2 is 1.539 g cm-3.
It can be soluble in alcohol, benzene, ether, and oil.
Concepts of Carbon Disulfide Formula
Carbon disulfide can react with other elements and it is highly flammable:
Since it is flammable it can undergo the process of combustion and form sulphur dioxide.
CS2 + 3O2 CO2 + 2SO2
Reaction with nucleophiles: CS2 is a weaker electrophile when compared to isoelectronic carbon dioxide. When nucleophiles are reacted with CO2 the reactions are said to be highly reversible and the produced products can be isolated with strong nucleophiles. Where reactions with CS2 are more favoured where the products are formed with less reactive nucleophiles.
Reaction with amines produces dithiocarbamates.
2R2NH + CS2 → [R2NH2+][R2NCS2-]
Reaction with alkoxides forms xanthates.
RONa + CS2 → [Na+][ROCS2-]
Reaction with sodium sulphide produces trithiocarbonate.
Na2S + CS2 → [Na+]2[CS32-]
Reduction: When carbon disulfide undergoes a reduction process with sodium it produces sodium 1,3-dithiole-2-thione-4,5-dithiolate and sodium trithiocarbonate.
4Na + 4CS2 → Na2C3S5 + Na2CS3
Chlorination: The chlorination of CS2 provides carbon tetrachloride.
CS2 + 3Cl2 → CCl4 + S2Cl2
Carbon Disulfide Uses
Due to the properties of carbon disulfide, it can be found used in a few applications.
The industrial uses are the manufacture of viscose rayon and cellophane film.
It is used as an intermediate in the chemical synthesis of carbon tetrachloride.
It is used in the production of organosulfur compounds like xanthates and dithiocarbamates. These are widely used in extractive metallurgy and rubber chemistry.
Preparing soil disinfectants.
Used as a solvent for fats, resins, sulphur, bromine, iodine, phosphorus, etc.
In the manufacture of electronic vacuum tubes.
Health Hazards
Acute Effects
Acute inhalation exposure of humans caused changes in breathing and some chest pains during an accidental release of carbon disulfide.
Nausea, vomiting, dizziness, fatigue, headache, mood changes, lethargy, blurred vision, delirium, and convulsions have also been reported in humans acutely exposed by inhalation.
convulsions have also been reported in humans acutely exposed by inhalation.
Brain chemistry changes and sensory and motor nerve conduction alterations were observed in rats acutely exposed to carbon disulfide by inhalation.
Animal studies show transitory effects associated with the target organ toxicity (central nervous system (CNS), blood, liver, eyes) seen from chronic exposure.
Tests involving acute exposure of rats, mice, and rabbits have shown carbon disulfide to have low acute toxicity from inhalation and moderate acute toxicity by ingestion.
Reproductive/Developmental Effects
Reproductive effects, such as decreased sperm count and decreased libido in men and menstrual disturbances in women, have been reported from occupational settings involving inhalation exposure to carbon disulfide.
Developmental effects, including skeletal and visceral malformations, embryotoxicity, and functional and behavioural disturbances, have been observed in several animal studies across a wide exposure range.
Pharmacokinetic studies indicate that carbon disulfide and its metabolites cross the placenta and localise in the target organs of the foetus (brain, blood, liver, and eyes).
Cancer Risk
In a study of workers exposed by inhalation to carbon disulfide and other solvents, an increased incidence of lymphatic leukaemia was reported. However, there were many confounding factors in this study, making it difficult to interpret the results.
EPA has not classified carbon disulfide for human carcinogenicity.
Conclusion
In this article, we learnt about liquid sulphur. It has both advantages and disadvantages. Where the advantages include its applications in several industries. Whereas its disadvantages include health hazards, it’s few chemical properties that are dangerous to the living organisms.
FAQs on Carbon Disulfide Explained: Properties, Uses & Preparation
1. What is Carbon Disulfide and what is its chemical formula?
Carbon Disulfide is a colourless, neurotoxic, and highly volatile liquid inorganic compound. Its chemical formula is CS₂. While pure Carbon Disulfide is odourless, the commercial-grade substance often has a foul, unpleasant smell due to impurities like hydrogen sulfide.
2. What are the main uses of Carbon Disulfide in industry and agriculture?
Carbon Disulfide is a versatile chemical with several important applications. Its primary uses include:
- As a solvent for nonpolar substances like fats, oils, resins, rubber, and phosphorus.
- In the manufacturing of viscose rayon and cellophane film.
- As a chemical intermediate in the production of carbon tetrachloride (CCl₄).
- In agriculture, it has been used as a soil disinfectant and a fumigant to control insects and pests in stored grain.
3. Describe the key physical properties of Carbon Disulfide.
The important physical properties of Carbon Disulfide (CS₂) are:
- Appearance: It is a clear, colourless liquid at room temperature.
- Solubility: It is immiscible (does not dissolve) in water but is soluble in many organic solvents like ethanol, ether, and benzene.
- Density: It is denser than water, with a density of approximately 1.26 g/cm³.
- Boiling Point: It has a low boiling point of 46.3 °C, which makes it highly volatile.
- Flammability: It is extremely flammable with a very low autoignition temperature.
4. Why is Carbon Disulfide (CS₂) considered a good nonpolar solvent?
Carbon Disulfide is an excellent nonpolar solvent due to its molecular structure. The molecule has a linear geometry (S=C=S), with the carbon atom in the centre and two sulfur atoms on opposite sides. Although the C=S bonds have some polarity, the symmetrical arrangement causes the individual bond dipoles to cancel each other out. This results in a molecule with a zero net dipole moment, making it nonpolar. According to the principle of "like dissolves like," nonpolar solvents are effective at dissolving other nonpolar or weakly polar substances.
5. What are some important chemical reactions involving Carbon Disulfide?
As per the CBSE syllabus, two key chemical reactions of Carbon Disulfide are:
- Combustion: It burns in the presence of oxygen to produce carbon dioxide and sulfur dioxide. The balanced equation is:
CS₂ + 3O₂ → CO₂ + 2SO₂ - Chlorination: It reacts with chlorine in the presence of a catalyst (like anhydrous aluminium chloride) to form carbon tetrachloride and disulfur dichloride. The balanced equation is:
CS₂ + 3Cl₂ → CCl₄ + S₂Cl₂
6. How does the linear molecular structure of Carbon Disulfide influence its properties?
The linear structure of Carbon Disulfide is fundamental to its physical and chemical properties. Because the S=C=S geometry is perfectly symmetrical, the molecule is nonpolar. This nonpolarity directly explains why it is a good solvent for other nonpolar substances like iodine, sulfur, and fats. Furthermore, the weak intermolecular forces (London dispersion forces) between CS₂ molecules, a consequence of its nonpolar nature, result in its low boiling point and high volatility.
7. Why is Carbon Disulfide considered highly hazardous and what precautions are necessary for handling it?
Carbon Disulfide is considered highly hazardous for two main reasons: its high flammability and its toxicity. It has a very low autoignition temperature (around 90 °C), meaning it can ignite without a spark or flame if it comes into contact with a hot surface. It is also a potent neurotoxin that can cause severe damage to the nervous system upon inhalation or absorption. Therefore, strict safety precautions are essential:
- It should be stored in a cool, well-ventilated area, away from all sources of ignition.
- Containers must be tightly sealed and are often stored under a layer of water or an inert gas to prevent vapours from escaping.
- Handling should always be done in a fume hood while wearing appropriate personal protective equipment (PPE), including gloves and respiratory protection.
