Design, Synthesis And Basic Application Research Of Amino Acid-based Oil Flooding Surfactants

Petroleum plays a strong supporting role in national economic development during the process of China's modern industrialization.It is an objective fact that our country's oil depend on imports,due to the energy structure of"more coal,less oil,and poor gas".In addition,high temperature,high salt,low permeability,high viscosity reservoir environment,and environmental pollution caused by tertiary oil recovery also increase challenges to oil exploitation.Therefore,the performance requirements for the surfactants of tertiary oil recovery are gradually increasing.It is necessary to comprehensively consider the properties of antibacterial,easily degradable,high surface activity,and so on.This subject conducts in-depth research of amino acid surfactants and their application prospects in tertiary oil recovery,intending to further industrial application.In this work,first,long-chain fatty alcohols are used as raw materials to prepare long-chain fatty aldehydes through Collins reagent.Then,triethyl phosphite and ethyl chloroacetate are used to prepare phosphoryl ylide intermediates that react with aliphatic aldehydes through Wittig-Horner reaction to obtain?,?-unsaturated carbonyl compounds.A series of single-chain N-alkyl amino acid surfactants connected by C-N bonds are obtained by aza-Michael reaction using seven amino acids as raw materials.Finally,two Gemini amino acid surfactants are obtained by bimolecular nucleophilic substitution and Kabachnik-Fields reaction,which 1,4-dibromobutane and glutaraldehyde as bridging groups are used.The results of performance tests of a series of amino acid surfactants demonstrate that oil-displacing agents based on different amino acid residues show different properties.Among them,histidine-based surfactants have the best performance with the lowest surface tension and critical micelle concentration.In addition,the contact angle of the histidine-based surfactants is the smallest and the equilibrium time of the contact angle is the shortest.The single-chain amino acid surfactant aqueous solution can reach ultra-low interface tension(10^-3m N/m)with Shengli crude oil under the condition of 50000 ppm Na Cl solution.Gemini amino acid surfactants have better performance than single-chain amino acid surfactants.They have lower surface tension,critical micelle concentration,good thermal stability and salt resistance(non-calcium and magnesium ions),and universality.