A Quick Note On Sulphur

Sulphur is a nonmetallic chemical element that belongs to the periodic table’s oxygen group and is among the highly reactive elements. Pure sulphur is an odourless, fragile and dull yellow solid that is a poor conductor of electricity and poorly soluble in water. It generates sulphides when it mixes with all metals but gold and platinum. It also forms compounds with numerous nonmetallic elements. Every year, millions of tonnes of Sulphur are extracted, primarily for the production of sulfuric acid, which is widely utilised in commercial industries.

Allotropic forms of sulphur

Sulphur has many allotropes, the most prominent being yellow rhombic (ɑ-sulphur) and monoclinic (β-sulphur).

ɑ-sulphur

At ambient temperature, rhombic sulphur is stable. Still, it changes to monoclinic sulphur when heated at over 369K. This allotrope has a yellow colour, a melting point of 385.8K, and a specific gravity of 2.06. When the roll sulphur solution in CS2 evaporates, rhombic sulphur crystals emerge. It is not soluble in polar solvents like water but somewhat soluble in organic solvents like benzene, alcohol, and ether.

β-sulphur

It has a melting point of 393K and a specific gravity of 1.98. This type of sulphur is made by melting rhombic sulphur in a dish and chillin it until a crust forms. The leftover liquid is poured out through two holes in the crust. When the crust is removed, colourless needle-shaped crystals of sulphur develop.

 It is stable at 369K and converts to ɑ-sulphur below this temperature.

 ɑ-sulphur, on the other hand, is stable below 369K and converts into β-sulphur beyond this temperature. 

Both types are stable at around 369K. This is referred to as the transition temperature.

Uses of Sulphur

Sulphur is utilised so extensively in industrial processes that its consumption is frequently viewed as a trustworthy indication of industrialisation and the status of the country’s economy.

• Roughly more than half of all sulphur generated is turned into sulphuric acid, the primary usage of which is in the production of fertilisers.
• Other notable applications include the manufacture of dyes, surfactants, textiles, petrochemical products, metal sheets, explosives, and energy storage systems.
• Sulphur that has not been turned into sulfuric acid is required to make paper, pesticides, antimicrobials, colouring agents, and various other goods.

Compounds of Sulphur

Here are a few compounds of sulphur:

Sulphur Dioxide

When sulphur is burned in air or oxygen, it produces sulphur dioxide and a little sulphur trioxide (6-8%). It is easily produced in the laboratory by processing sulphites with weak sulphuric acid. It is manufactured commercially as a byproduct of the heating of sulphide ores. After drying, the gas is liquefied, compressed  and contained in steel cylinders.

Sulphur dioxide is a colourless gas with a strong odour and is extremely water-soluble. It liquefies at ambient temperature under two atmospheres of pressure and boils at 263K.

When sulphur dioxide is transported through water, it generates a sulphurous acid solution. It quickly interacts with sodium hydroxide solution to generate sodium sulphite, which reacts with additional sulphur dioxide to produce sodium hydrogen sulphite.

In the presence of charcoal (which acts as a catalyst), sulphur dioxide combines with chlorine to form sulphuryl chloride, SO2Cl2. Oxygen oxidises it to sulphur trioxide in the presence of a vanadium(V) oxide catalyst.

Uses of Sulphur Dioxide

Sulphur dioxide (SO2) is an inorganic chemical that is a heavy, colourless, and toxic gas.

• Its primary application is as a starter for sulphur trioxide, SO3, and sulfuric acid, H2SO4.
• It is also used as bleach and a reducing agent in manufacturing.
• It is used in food preservation and fruit ripening.
• It is used to preserve wine from bacteria and other microbes.
• It functions as both a bleaching agent and a disinfectant to eliminate extra chlorine.
• Sulphuric acid is often used as a disinfectant, anti-chlorinator, and preservative.
• Sulphur dioxide makes industrial chemicals such as sulphuric acid, sodium hydrogen sulphite, and calcium hydrogen sulphite.
• Various organic and inorganic compounds are dissolved in liquid sulphur dioxide as a solvent.

Sulphuric Acid

Sulphuric acid is among the world’s most significant industrial compounds.

The contact process consists of three steps:

• burning sulphur or sulphide ores in the air to generate SO2,
• converting SO2 to SO3 by reaction with oxygen in the existence of a catalyst (V2O5), and
• absorption of SO3 in H2SO4 to produce Oleum (H2S2O7)

Purification of the SO2 generated includes the removal of dust and other contaminants such as arsenic compounds. The catalytic oxidation of SO2 with O2 to yield SO3 in the presence of V2O5 is a critical step in the production of H2SO4.

The reaction is exothermic and reversible, and the advanced reaction causes a volume drop. As a result, low temperature and high pressure are the best conditions for the highest yield. However, the temperature should not be too low, or the reaction would be too sluggish.

Conclusion

Sulphur exists in a variety of allotropes. The most prominent of them are alpha and beta forms of sulphur. Sulphur reacts with oxygen to form oxides like SO2 and SO3. The exact combination of sulphur and oxygen produces SO2. SO2 is used in the production of H2SO4. Sulphur may be converted into a variety of oxoacids. The most significant of these is H2SO4. A contact technique produces it. It acts as a dehydrator and an oxidiser. It is utilised in the production of a variety of chemicals.