Responsive Systems Fabricated By Polyetheramine-fatty Acid Ion Pairs And Their Applications

Dr.Zhang proposed amphiphiles fabricated by non-covalent bond,which also named as supramphiphile.In recent years supramphiphile was attractive for its easy preparation,unique self-assembly behaviors and readily dissociation,which can be used to fabricate stimuli-responsive systems.The super molecules prepared by electrostatic interaction,usually called as ion pairs,can be easily prepared by mixing cations and anions,which was even more simple than other super molecules.The polyetheramine was amine with EO or PO groups introduced to its backbone,which has lower bio-toxicity and has been widely applied.The ion pair can be prepared by mixing them with fatty acids,which can be served as surfactants with high surface activity.The electrostatic interaction between cations and anions,the EO or PO groups at the backbone of polyetheramine endow these ion pairs unique stimuli responsive behaviours.As a result,research in these ion pairs can achieve a better knowledge of responsive systems,and their application in the production like EOR was also attractive.There are three parts in this article based on the research in ion pairs formed by polyetheramine and fatty acids.The first is using such ion pairs as surfactants and prepare stimuli responsive aqueous foams.The second is fabricate the bio-safe alkali/surfactant/polymer flooding systems,based on the properties of polyetheramines in-situ soap generation with the fatty acids in crude oil.The thrd is serving the surfactants prepared by polyetheramine and fatty acids as ionic liquids,and their unique temperature phase behavior was also investigated.There are four parts of outline and contents in total.The first part is the comprehensive introduction of research background.Information provided in this chapter was listed as follows:The basic concept of surfactant and colloidal chemistry;The background of supramolecular surfactants(or named as supramphiphile);The properties of fatty acids neutralized by counter-ions,and their corresponding assemblies;The basic concept of responsive foams and mechanisms of their responsive behaviour;The introduction of alkali/surfactant/polymer flooding and the difficulties brought by conventional chemicals;The basic information of protic ionic liquids,and the impact of the type of cations and anions.The objective and the scientific significance of the article are also listed at the end of this part.The second part is about one series of "pseudogemini" surfactants(short for D-LCFA)with superior surface activity and responsive behavior,which are synthesized by mixing long chain fatty acids(LCFA)and polyetheramine D 230 at fixed molar ratio(2:1).Non-covalently bonded building blocks indicate that CO2-responsive aqueous foams can be obtained by utilizing such pseudogemini surfactants.1H NMR and FT-IR characterizations prove that the building blocks of these surfactants are associated by electrostatic interaction.The synthesis(Bronsted acid-base reaction)is simple and eco-friendly."Pseudogemini" structure enables D-LCFA to reduce surface tension of aqueous solution effectively,thus facilitating foam generation.Rheograms,FF-TEM and Cryo-TEM results prove that different aggregates in D-LCFA aqueous solutions lead to different foam properties.Bubbling of CO2 for about 30 s leads to the rupture of aqueous foams generated by D-LCFA,while removing CO2 by bubbling of N2 at 65℃ for 10 min enables re-generation of foams.The CO2-responsive foaming properties can be attributed to dissociation of D-LCFA upon bubbling of CO2 and re-association upon removal of CO2.The effective CO2-responsive foams can be applied to many areas,such as foam fracturing,foam enhanced oil recovery or recovering of radioactive materials.The third part is the investigation of the feasibility of D 230 to displace the crude oils in reservoirs.The application of conventional alkalis(NaOH or Na2CO3)in alkali/surfactant/polymer(ASP)flooding is rather limited due to their intrinsic drawbacks,including precipitating during injection into formation water with a high divalent ion concentration and enhancing the dispersibility of clays(e.g.,montmorillonite(MMT)or kaolinite)in water,which lead to damage to reservoir formations and bring about difficulties in treating produced fluids.Here,we propose polyetheramine D 230 as an alternative alkali to avoid these problems.D 230 is a diamine linked by poly(oxypropylene)backbones.Interfacial tension and emulsification measurements proved that D 230 can neutralize the acidic components in crude oil to generate surface-active soaps,which facilitate oil emulsification in water.Contact angle measurements indicated that an oil-contaminated quartz surface treated with D 230/SP blends was successfully altered from oil-wet to water-wet.Sand pack flooding measurements demonstrated that a D 230/SP injection was able to mobilize 19.23%of the original oil in place(OOIP)after thorough water flooding.Rheograms of alkali/polymer blends showed a reduced impact of D 230 on viscosity.Static bottle tests indicated that no precipitation occurred after D 230 was injected into formation water with a high Ca2+concentration.Colloidal stability measurements of clay dispersions suggested that D 230 can inhibit clay dispersibility.As an alternative alkali in ASP flooding,D 230 not only facilitates enhanced oil recovery(EOR)but also solves problems such as precipitation,high biotoxicity,reduced fluid viscosity and enhanced clay dispersibility brought about by conventional inorganic and organic alkalis.These advantages make D 230 an eco-friendly choice as an alkali for ASP flooding.The fourth part is the investigation of using surfactants in second part as protic ionic liquids.Ionic liquids can be served as entrainer or activator of catalysts while it is hard to separate and reuse them after the reaction.Using ionic liquid with properties of reversible phase transfer is a good choice.In this work,a series of room temperature ionic liquids named PEA-FA were prepared by simply mixing polyetheramines(PEA)and fatty acids(FA).1H NMR and FT-IR tests proved that amines and fatty acids are associated by electrostatic interaction and PEA-FA can be regarded as protic ionic liquids.Rheograms further proved it and showed PEA-FA has relatively low viscosity.TGA and DSC tests indicated the melting point of PEA-FA was lower than room temperature,and it’s thermo stability was poor.Partition coefficients tests proved that the PEA-FA can transfer between the EtOAc phase and aqueous phase reversibly.As qualified protic ionic liquids,PEA-FA can be used as the entrainer or activator of organic reaction.Its temperature sensitive behavior makes it possible to be easily reused after the reaction.