There are numerous uses and application of Sulfolane. Few of the most prominent are mentioned here.

• Acid Gas Treatment
• Aromatic Extraction
• Reaction Solvent
• Fractionization
• Extractive Distillation
• Polymerization Solvent
• Dyestuffs
• Printing Ink
• Agrochemicals
• Pharmaceutical
• Electronics

 Acid Gas Treatment

Acid gas Treatment or Gas Sweetening is a process in which acidic gases are removed from the natural gas. Acidic gases such as Hydrogen Sulfide, Carbon dioxide, Carbon Oxysulphide, carbon disulphide and mercaptans.

This treatment is done trough shell licensed process called Sulfinol process. In this process, Sulfolane is the main ingredient and component. This process is explained in brief details in the Sulfinol section of this report.

 Aromatic Extraction

Because Sulfolane has the properties of high solvency, it plays a vital role in the liquid-liquid extraction of benzene-toluene-xylene aromatics from reformate or hydro treated pyrolysis naphtha.

Using Sulfolane for this process yields a >99.9% purity in the final product. After the separation of the products, sulfolane can easily be recovered for other uses. This results in decreasing the operational costs and increases the plant productivity while achieving the highest purity product achievable.

Extractive Distillation

Extractive distillation is a process which is only used when the separation of two fluids with very close boiling points is required to be separated. A point in case would be of the Separation n-propyl alcohol and sec-butyl alcohol, butane and 2-butene.

SULFOLANE effectively separates n-propyl alcohol from sec-butyl alcohol (2- butanol). These alcohols cannot be separated easily by fractional distillation as both their anhydrous and water binary azeotrope boiling points are within 1.7°C of each other. The separation is readily accomplished by extractive distillation with SULFOLANE as a reflux liquid. Since the SULFOLANE depresses the vapour pressure of the secbutyl alcohol, n-propyl alcohol distils overhead and the sec-butyl alcohol/SULFOLANE is recovered as a bottoms product. This procedure is of use in separating mixtures of these and other close-boiling alcohols.

  Fractionation

The process of the breakdown or separation of fatty acids into saturated and unsaturated components is called Fractionization

With the help of Sulfolane, the Preliminary liquid phase extraction allows the fractionation of fatty acids into saturated and unsaturated components.

 Reaction Solvent

The chemical properties of Sulfolane make it an excellent solvent for chemical reactions, particularly those where anhydrous and polar solvents are required. Some examples of these reactions are listed below.

• Quantitative quaternisation of Pyridine, 4-picoline and 4-isopropylpyridine in Sulfolane with n-butyl bromide. Use of SULFOLANE eliminates the side reactions which may be experienced when other reactions solvents are used.
• Olefin isomerisation, Friedel-Crafts alkylations, carbonium ion rearrangement and hydrogen transfer processes with hydrofluoboric acid and many more.

 Polymerization Solvent

SULFOLANE is used as a polymerisation solvent for various systems. These systems may include but are not confined to: water soluble polysaccharide polymers prepared from glucose solution in SULFOLANE with a phosphoric acid catalyst.

Apart from the above mentioned uses of Sulfolane in polymerization, following are some other uses of Sulfolane in this category.

• Co-polymerisation of aromatic polycarboxylic acids with polyisocyanates, polycarboxylic acids with partially acylated diamines and/or aminocarboxylic acids, aromatic diamines with a tricarboxylic acid or anhydride and trimellitic anhydride with 4,4′ – diphenylmethane diisocyanate.
• Polyether polyols have been prepared from 1,3,5-triazines and oxirane compounds.
• Linear aromatic polyethers have been produced by the condensation of 4,’ – dihydroxybiphenyl, or hydroquinone, with 4,4′ – dichlorodiphenyl sulphone.
• Sulfolane can be used in separation and recovery of polysulphone resins

Dyestuffs

An added application of SULFOLANE is to be used as an intensifier for increasing the colourfastness of dispersed dyes which are applied to hydrophobic synthetic fibres. Aqueous SULFOLANE combined with concentrated solutions of basic dyes are useful for dyeing acrylic fibres.

Sulfolane has good storage capabilities due to the aqueous compositions of dyes which prove a great combination for dyeing and printing materials with a  high colour build-up.

Printing Ink

The use of Sulfolane for the production of Jet printing ink formulations containing SULFOLANE have develops the inks ability to have good storage stability, does not clog printer nozzles, and give high quality prints, with good fixation on substrates.

SULFOLANE has also been used in ink compositions to provide good water resistance and develop good writing properties especially after the pens have been left uncapped for long periods. Approximately 15% Sulfolane is used in the mixture.

Direct printing, photographic silver halides emulsions containing SULFOLANE have been developed with the advantages conferred are sensitivity, stability and appearance. A stripping composition containing SULFOLANE for the removal of unexposed areas of photo resist from a support in lithographic imaging processes has been developed. Non-woven adsorbents for writing units and cosmetic solutions have been made by treating a mixture of crimped acrylic fibres and, for example, polyester fibres with SULFOLANE.

Agrochemical

The high chemical stability and thermal stability of Sulfolane makes it the best raw material for the production and formation of insecticides, herbicides, fungicides. The advantage of using Sulfolane is that it does not react due to thermal and chemical stability.

Other advantages included the miscibility of Sulfolane with water, Recoverable and recyclable nature of the product and many more.

Pharmaceutical

T can be used as an intermediate or as a process solvent in the pharmaceuticals applications. Advantages of using Sulfolane are the thermal and chemical stability, miscibility in water, high boiling point, versatile in use with a wide range and many others.

Electronics

Sulfolane, due to its high solvency property, is used as a solvent in Lithium Ion Batteries between the anodes. Sulfolane provides higher efficiency in performance than the old use of electrolytes.