Synthesis And Property Of Fluorocarbon Surfactant

Foaming agents is a key factor to optimize the nitrogen foam fracturing technique, whichis a kind of critical technology in coal-bed gas exploitation. So far, no one surfactant can meetthe requirements of foaming agents’ performance. Amide fluorocarbon surfactant hasadvantages of fluorocarbon surfactant and amide surfactant. It can meet the nitrogen foamfracturing’s needs for foaming agents’ performance. Synthesis and performance of amidefluorocarbon surfactant is systematically investigated in this paper.Amide fluorocarbon surfactant is synthesized via fatty acid process and ester-interchangemethod, respectively using perfluorooctanoic acid and diethanolameine, isopropanolamine,diisopropanolamine, diglycolamine. The chain structure of the products was characterized byinfrared spectra (IR) and foam performance was also monitered. The results showed thatisopropanolamine is the optimum synthetic monmer and N-(2-hydroxy ethyl) perfluorooctaneamide is a optimum foaming agent.The synthesis parameters such as reaction temperature, reaction time, catalyst content,ratio of reactants on the chain structure, foam property and surface tension had beeninvestigated by single factor method. The results indicated that temperature and time are themain parameters. Furthermore, orthogonal experiment has been carried out to optimize theexperimental conditions for N-(2-hydroxy ethyl) perfluorooctane amide synthesis. The resultsexhibited that synthesis temperature of amide esters is the main factors using fatty acidmethod, while synthesis temperature of amide esters and perfluorooctane amide is the mainfactor for ester-interchange method.In addition, the structure, performance and synthesis mechanism had been investigated.The results showed that structure, expanding property, surface tension, acidic and alkaliresistances, salt resistance, temperature resistance and compatibility of the samplessynthesized with different methods are nearly same. In addition, the synthesize samples havebetter foaming performance and surface activity than the commercial sodium dodecyl sulfate(SDS), especially using them in the severe conditions. The in-situ IR spectra indicated fattyacid process meant amide esters was acquired by amidation and esterification, then ittansfered to perfluorooctane amide by ammonolysis; while ester-interchange method meantperflurooctanoic acid methyl was acquired by amidation, then it tansfered to perfluorooctane amide by ammonolysis.