Sulphonation: Definition, Reaction, Sulfonation of Benzene, Uses and Application

Sulphonation Overview

Sulfonation, also referred to as sulphonation in chemistry, is any of many processes that can result in the synthesis of sulfuric acids. The reactions of natural halogen compounds with inorganic sulfites, the oxidation of specific classes of organs containing thiols, and the reaction of aromatic hydrocarbons with sulfuric acid or chlorosulphonic acid are all examples of sulfuration processes.

What is Sulphonation?

Sulphonation is the process of substituting a hydrogen atom for the SO3H sulfonic acid group. A typical alkane can be sulphonated by treating it with oleum (fuming sulfuric acid), starting with hexane. When replacing a hydrogen atom, the process is very slow because the tertiary value is much higher than the secondary value, and the primary value is much slower. Tertiary hydrogen atoms in isobutane make it simple to sulfonate and produce t-butyl sulfuric acid:

                              H2SO4/SO3 → (CH3)3CSO3H + H2SO4

Sulphonation of Other Compounds

Given below are sulphonation of other compounds:

Benzene Sulphonation 

Benzene is heated with fuming sulfuric acid (H2SO4+ SO3) during the sulfonation Process to produce benzenol. The nature of the effect, shown below, is reversible.

Sodium Xylenesulfonate

A hydrotrope is an organic compound that enhances the capability of water to dissolve other molecules. Sodium xylenesulfonate is a hydrotrope.  The risk of negative health effects from consumer and occupational use of sodium xylene sulfonate is predicted to be negligible because it is a low hazard compound.

Mechanism of Sulphonation

It is not settled, due in part to the challenges in determining the sulfonating species nature (cf. nitration). As a result, there are numerous options for sulphonation with concentrated sulphuric acid, each resulting from a different equilibrium, e.g.,

• 2H2SO4 -> SO3 + H3O+ +HSO4-
• SO3 + H2SO4 -> H2SO4(SO3) or H2S2O7
• 3H2SO4 -> SO3H+ + H3O+ + 2HSO4-

Uses and Applications of Sodium Xylenesulfonate

Sodium xylenesulfonate, also known as sodium xylene sulfonate or SXS, is a versatile chemical compound that finds application in various industries. Here are some common uses and applications of sodium xylenesulfonate:

1. Surfactant: Sodium xylenesulfonate is primarily used as a surfactant, which means it reduces the surface tension of liquids and helps in the dispersion of substances. It is widely employed in the production of various household and industrial cleaning products, such as detergents, liquid soaps, dishwashing liquids, and industrial cleaners.
2. Emulsifier: SXS can act as an emulsifier, facilitating the mixing of immiscible substances like oil and water. It is utilized in emulsion polymerization processes, where it aids in the formation and stabilization of emulsions. This property makes it useful in the manufacture of adhesives, coatings, and paints.
3. Textile industry: Sodium xylenesulfonate is employed in the textile industry as a leveling agent and dye dispersant. It helps ensure uniform dyeing of fibers by preventing uneven coloration and facilitating the dispersion of dyes.
4. Oil and gas industry: SXS is used in the oil and gas industry as a component of drilling muds and completion fluids. It helps reduce the friction between the drilling equipment and the borehole walls, enhancing the efficiency of drilling operations.
5. Agriculture: Sodium xylenesulfonate can be used as a wetting agent and dispersant in agricultural formulations such as herbicides, insecticides, and fungicides. It aids in the even spreading and effective distribution of these formulations on plant surfaces.
6. Construction industry: SXS is employed in the production of cement and concrete as a plasticizer and dispersant. It helps to improve the workability and flow properties of concrete mixes, making them easier to handle and reducing the water content required for a given consistency.
7. Personal care products: Sodium xylenesulfonate is sometimes used in personal care products like shampoos and conditioners as a cleansing and foaming agent. It contributes to the formation of lather and aids in the removal of dirt and oils from the hair and scalp.

It's worth noting that the specific applications of sodium xylenesulfonate may vary depending on the formulation and requirements of different industries and products.

Sulphonation Reaction

Sulphonation is the process of substituting a hydrogen atom for the SO3H sulphonic acid group.

Sulfonation is the process of incorporating a sulphonic acid group into an aromatic compound.

Dodecylbenzenesulfonic Acid:

Dodecylbenzenesulfonic Acid is a dense liquid ranging in color from light yellow to brown. It falls under the category of dodecylbenzene and is used in detergent production. It is listed as a Hazardous Substance due to citations by the EPA and DOT. Specifically, it is on the Special Health Hazard Substance List due to its corrosive nature.

Sulphonation of Phenol:

The chemical reaction between phenol and concentrated sulfuric acid is known as the sulphonation of phenol. The resulting sulphonation product depends on the operating temperature.

At lower temperatures, phenol reacts with concentrated H2SO4 to form o-phenol sulphonic acid. The interaction between the neighboring SO3H group and OH group predominates at lower temperatures, leading to ortho isomers.

However, at higher temperatures, these interactions do not occur, and steric repulsion overcomes the attraction. Consequently, p-phenol sulphonic acid is obtained, as represented in the figure above.

The reason behind the rate of reaction difference between benzene and hexadeuterobenzene during sulphonation lies in the isotopes of hydrogen.

Protium contains one proton and zero neutrons, while Deuterium has a neutron, making it twice as heavy. This mass difference results in smaller vibrations or a stronger, shorter bond. As a result, a Carbon-Deuterium bond is stronger compared to a Carbon-Protium bond.

Sulphonation: Things to Remember

1. The process by which a hydrogen atom is replaced with a sulfonic acid group, SO3H, is named sulphonation.
2. In the instance of hydrogen atom substitution, secondary is much higher than primary, and tertiary is much higher than secondary substitution of a primary hydrogen atom in sulphonation, which is highly slow.
3. The Idea that sulfur trioxide is an active species is supported by external research based on kinetic measurements in concentrated sulfuric acid and oleum. For aqueous sulfuric acid, this is also believed to be the case.
4. Heating benzene with fuming sulphuric acid (H2SO4 + SO3) to generate benzenesulfonic acid is the process of sulphonation of benzene. This reaction, depicted below, is reversible in nature.
5. Dodecylbenzene is a particular kind of drug. Sulfonic acid is a liquid that is thick and can be anywhere from light brown to yellow in color. It might be used to make detergents in the future.

The interaction of phenol with strong sulphuric acid refers to the sulphonation of phenol. The sulphonation product can be determined by the operating temperature.

The interaction of phenol with strong sulphuric acid refers to the sulphonation of phenol. The sulphonation product can be determined by the operating temperature.