Sulfonate-type Gemini surfactant has good surface activity, does not produce calcium and magnesium salt precipitation in hard water, and is resistant to acid and alkali. It can be specially designed according to different uses to meet the special requirements of various application fields, and the raw materials can be obtained from a wide range of sources, such as mineral oil or automatic plants, and its uses are very wide. There are three main approaches to the synthesis of sulfonates surnamed Gemini surfactants.
The first synthesis idea: start with the connecting group, directly use the ready-made connecting group or synthesize a specific structure of the connecting group, first introduce two hydrophobic chains on the connecting group, then react with a sulfonation/vulcanization reagent to introduce two hydrophilic chains, and finally through neutralization, purification, and other steps to prepare the finished product.
Sodium dialkyl sulfonated diphenylmethane Gemini surfactant was synthesized from diphenylmethane and α-olefin by alkylation, long-chain alkyl group connected to a benzene ring, sulfonation, and neutralization with chlorosulfonic acid. The product has high surface activity.
(1) Alkylation Reaction
(2) Sulfonation Reaction
(3) Neutralization Reaction
The intermediate product N, N'-dialkyl Ethylenediamine was synthesized from brominated n-alkanes and Ethylenediamine, and the sulfonated Gemini surfactant SGS-n (n=8, 10, 12, 14) with different carbon chain lengths was prepared by the reaction of the synthesized intermediate product with 1,3-propyl Sultone.
The second synthesis approach is to first select hydrophobic groups to react with linkers, or select linkers with hydrophobic groups, and then react with sulfonation/sulfation reagents to introduce hydrophilic groups. After neutralization and purification, the finished product is obtained.
Use 1,2-diepoxydodecyl as raw material, react with bromododecanoic acid to obtain a double-chain compound, and then reduce it with LiAlH4. The action generates a sulfonate-type anionic Gemini surfactant whose linking group is -(CH2CH2O)x (x=0, 1, 2, 3), and its synthetic route is as follows.
The third synthesis idea: directly adopt the conventional sulfonate-type surfactant to react with the linker, breaking the traditional synthesis idea that the sulfonate-type Gemini surfactant must first introduce a linking group or a hydrophobic chain, for the synthesis of a new type of Gemini Surfactants to provide theoretical support. The target product is synthesized by using α-sulfo ester anti-acid and polyethylene glycol, etc., and the synthetic route is:
No matter which synthesis method is adopted, the active site of the reaction between the hydrophobic group, linker, and sulfonic acid / sulfuric acid hydrophilic group determines the arrangement of each group in the molecular structure of Gemini surfactant, which determines the molecular shape of Gemini surfactant, which is the prerequisite for the design and synthesis of Gemini surfactant, and the type of hydrophobic group, linker, and the hydrophilic group determines the reaction site. The variability of group and group arrangement leads to a wide variety of molecular structure changes of Gemini surfactants. How to design Gemini surfactants with excellent properties at molecular level will attract enough attention in the industry.
