Oil Chem Technologies
Anionic surfactants
 
New Arylalkyl Sulfonates (AASA)

Oil Chem Technologies has developed a new family of anionic surfactants (patented) derived from the reaction of olefin sulfonic acids and various aromatic compounds. The new surfactants are different from conventional alkylaryl sulfonates in two important aspects:

The new arylalkyl sulfonates are prepared from the reaction of an aromatic and an olefin sulfonic acid without the need of a conventional alkylation process. The conventional alkylaryl sulfonic acids are prepared by first alkylating an olefin in the presence of a catalyst followed by sulfonating with SO3 to form the alkylaryl sulfonic acid. The scheme of the new process compared to the conventional process is shown below.

new alkylation process

The new arylalkyl sulfonate has the sulfonate group attached to the alkyl chain and the conventional alkylaryl sulfonate has the sulfonate group attached to the aromatic ring as shown in the example below:

Conventional Alkylaryl Sulfonte, New Arylalkyl Sulfonate

The difference in the point of attachment of the sulfonate group accounts for the increased solubility, foaming, detergency, hardness tolerance, skin mildness and other properties as described, for example, in US Patent 6,043,391 and US Patent application 2004/0180805. The elimination of the alkylation process also allows for considerable savings in both the up-front investment for an alkylation plant and the on-going expense of operating the plant as shown below:

Equipment Conventional Process New Process
Alkylation Unit $75-80 million* $0
Sulfonation Unit $16 million $16 million
Neutralization Unit $2 million $2 million

 * Handbook of Petroleum Refining Process (1996) p 1.62

In practice, any aromatic may be used including benzene, toluene, xylene, naphthalene, alkyl naphthalenes, phenol, alkylphenols, alkoxylated phenols and alkoxylated alkylphenols. Alkylbenzenes may also be used to give a product with one sulfonated and one un-sulfonated chain. Also two olefin sulfonic acid groups may be added to give a gemini type surfactant with two anionic centers separated by an alkylated aromatic.

 

U.S Patents 6043391, 7605287