Research Of Thermal Stability Of Salt Resisting Surfactant And Its Adsorption Law In The Solid-liquid Interface

For the use of surfactants under the condition of high temperature and high salt reservoir,related properties of the alkyl phenol polyoxyethylene ether carboxylate and betaine surfactant were studied.With alkyl phenol polyoxyethylene ether and methyl chloroacetate as raw material,alkyl phenol polyoxyethylene ether carboxylate was synthesized through the method of carboxy methylation.The product yield was determinated by high performance liquid chromatography(HPLC).Preliminary synthetic conditions were determined as follows: reaction with sodium hydroxide to an hour at 40?,drops of chlorine methyl acetate between 65? and 70? and reaction with about 6 h,molar ratio of NP–7,NaOH and ClCH2COOCH3 as 1:2.2:1.2.The structures of the products were measured by IR and NMR.The thermal stability of alkyl phenol polyoxyethylene ether carboxylate was determinatied under different acid and alkaline conditions in simulation of high salinity formation water at 130?.When simulated formation water is neutral condition and PH of 5,it has good thermal stability.But under the condition of PH of 11 of simulated formation water its thermal stability overall declines significantly.In order to determinate the concentration of long carbon chain carboxyl betaine,its high performance liquid chromatography(HPLC)was established.The style of chromatographic column isr the SHIM-PACK VP-ODS C18 reversed phase chromatographic column(4.6mm*250 mm).The mobile phase consists of methanol and water(methanol/water =80:20~70:30 by volume).The column temperature is set at 40?.The flow rate is 1ml/min and the sample size is 20?L.Thermal stability of the dodecyl dimethyl carboxyl betaine(CBET-12)and dodecyl trimethyl ammonium chloride(1231)under the different condition of acid,alkalinity and salinity were determined.The result is that both of their thermal stability are good.The adsorption performance of dodecyl dimethyl carboxyl betaine(CBET-12)on carbonate rock surface were studied.The results showed that the adsorption quantity increases with the increase of NaCl content,and in different concentration of CaCl2 solution its the adsorption quantity(more than 4.0 mg/g)is larger than in NaCl solution,close to 2 times.