Synthesis And Performance Of Caboxylic Acid-type Imidazoline Amphoteric Surfactant

Carboxylic acid-type imidazoline amphoteric surfactant exploited by Hans. S. Mannheimer in 1950s has the significant status in the imidazoline-type surfactants (IAS) because of its excellent performance such as non-toxicity, non-stimulataion to eys and skin, good biological degradability, good foam stabilization, fine miscibility to other surfactant (cation, anion and noionic), sterilization and restraining ability for mildew. It is used as the indispensable compotent in the baby-shampoo and baby-cleansing cosmetic while applied in the fielid of detergent, fiber pliancy agent, assistant agent in weave industry, metal polishing agent and corrosion inhabitor.Using fatty acid andβ-hydroxyethyl ethylenediamine as raw materials, the series of carboxylic acid-type IAS were synthesized by two routes. The better synthesis condition for the intermediate in route 1 was confirmed by orthogonal experiments: the molecular ratio of fatty acid andβ-hydroxyyethyl ethylenediamine, reaction time, reaction temperature and degree of operation vacuum were 1:1.2, 4.5-5h, 154°C and 0.075MPa. The structure of amide intermediate and imidazoline intermediate was charactered by IR and the performace of products (surface tension, foaming power and penetrating power) was also determined. Despite the trend of the performance of product, the influence of the dosage of chloroactic acid, water-added sequence and pH value of intermediate were studied and the measuration of total solid content and NaCl content were also carried out while the effective substance being calculated.It has shown that the carboxylic acid-type IAS can be prepared without ring-closure step and the the dosage of chloroactic acid, water-added sequence and pH value of intermediate have significate effect on the performance of product. According to the result of the determination, the performance of oleic acid product was better than the performance of stearic acid product due to the double bond. Eventually, the better synthesis condition for the series of IAS was given according to the comparison of the performace.