Synthesis Of AGE/PGE-DETA Core Polyamide-amine And Its Demulsification Performance

During the tertiary oil recovery period,injecting a large amount of surfactants during the oil displacement process caused the produced fluid to exist mostly in the form of O/W emulsion.If left untreated,not only will the crude oil be lost,but storage equipment will also be damaged.In the process of petroleum processing,slick oil and dispersed oil are removed through physical and chemical methods,and oil resources are recovered.The emulsified oil content in the produced fluid is relatively high,the particle size is small and stable,and the conventional demulsifier has poor demulsification effect.The multi-branched demulsifier has the characteristics of fast demulsification speed and low demulsification temperature for small particle size emulsions.In this paper,different hydrophobic chains are used as the core to synthesize different polyamide-amines.It was used in the demulsification of emulsified oil emulsions,and the effect of different hydrophobic chains on the demulsification performance was explored,and the demulsification mechanism was studied.The main contents are as follows:(1)Using glacial acetic acid as solvent and toluene as water-carrying agent,1,5-diphthalimido-3-azazopentane(DETA-2PA)was synthesized by nucleophilic substitution-elimination reaction of phthalic anhydride(PA)and diethylene triamine(DETA).The structure was confirmed by FT-IR,1H-NMR,HRMS,HPLC,and elemental analysis.The effects of reaction time,reaction temperature,solvent dosage,and n(PA):n(DETA)on the yield of DETA-2PA were discussed.On this basis,the optimal process parameters obtained through response surface optimization were:n(PA):n(DETA)=2.5:1,reaction temperature 115?,solvent consumption 53 mL,reaction time 1 h,toluene consumption 20 mL.Under these conditions,the yield of DETA-2PA could reach 79.55%.Its thermal decomposition temperature was 157? by thermogravimetric test,and its fluorescence intensity was 4.91×104 a.u.by fluorescence test.(2)Using sodium hydride(NaH)as acid binding agent,DETA-2PA and acryloyl chloride(AC)were synthesized N,N-Bis[2-(1,3-dioxindole-2-yl)ethyl]Acrylamide(AC-DETA-2PA)in dichloromethane(CH2Cl2)through acylation reaction.The structure was confirmed by FT-IR,1H-NMR,HRMS,HPLC,and elemental analysis.The effects of reaction time,reaction temperature,amount of NaH,n(AC):n(DETA-2PA)on the amine value of AC-DETA-2PA were discussed.On this basis,the response surface optimization was used to obtain the best process parameters:The mass NaH of accounts for 7.8%of the total mass of the reactants,the reaction temperature was 25?,n(AC):n(DETA-2PA)=1.60:1.0,and the reaction time was 4 h,the AC-DETA-2PA amine value was 2.96 mgKOH/g.Its thermal decomposition temperature was 275? by thermogravimetric test,and its fluorescence intensity was 4.08×104 a.u.by fluorescence test.In the preliminary study of AC-DETA reaction,excessive hydrazine hydrate led to acylation of acryloyl hydrazine,resulting in a small amount of product.Therefore,no subsequent reaction was performed.(3)The ring-opening reaction of DETA-2PA and AGE(allyl glycidyl ether)was used to synthesize N-(3-allyloxy-2-hydroxypropyl)-bis[ethyl-(2-phthalic acid)formimide)](AGE-DETA-2PA).In ethanol solution,N-(3-allyloxy-2-hydroxypropyl)-bis(ethylamine)(AGE-DETA)was synthesized by hydrazinolysis of AGE-DETA-2PA with hydrazine hydrate.AGE-PAMAM was synthesized by Michael addition and acylation reaction of AGE-DETA with MA(methyl acrylate)and EDA(ethylene diamine).The structure of the product was confirmed by FT-IR,NMR.It was measured that its surface tension was as low as 66.042 mN/m.It was applied to the demulsification of ultrafine oil droplets O/W emulsion(average particle size of 167.6 nm).The study had shown that:under the conditions of AGE-PAMAM concentration of 2.0 g/L,time of 2 h and temperature of 45?,the dehydration rate of AGE-PAMAM was 98.5%,the oil content of the discharged sewage was 5.6 mg/L,and the light transmittance of the discharged water phase was 98.47%.(4)The ring-opening reaction between DETA-2PA and PGE was used to synthesize N-(3-phenoxy-2-hydroxypropyl)-bis[ethyl-(2-phthalimide)](PGE-DETA-2PA).In ethanol solution,N-(3-phenoxy-2-hydroxypropyl)-bis(ethylamine)(PGE-DETA)was synthesized by hydrazinolysis reaction of PGE-DETA-2PA.PGE-PAMAM was synthesized by Michael addition and acylation reaction of PGE-DETA with MA and EDA.The structure of the product was confirmed by FT-IR,NMR,and it was measured that its surface tension was 52.108 mN/m.Applying PGE-PAMAM to the demulsification of O/W emulsions,studies have shown that:under the conditions of PGE-PAMAM concentration of 2.5 g/L,time of 140 min and temperature of 55?,the dehydration rate of PGE-PAMAM demulsifier was 93.7%,the oil content of the discharged sewage was 63.8 mg/L,and the light transmittance of the discharged water phase was 85.56%.(5)Comparing the demulsification performance of AGE-PAMAM and PGE-PAMAM,the results showed that the dehydration rate of AGE-PAMAM exceeds 90%at room temperature(25?)and a short time(20 min).Through the stability test,AGE/PGE-PAMAM had a wider clarification area and a lower scattering area,indicating that the multi-branched demulsifier had better demulsification performance for the emulsion.And the TSI value(16.34)of AGE-PAMAM was greater than the TSI value(7.30)of PGE-PAMAM,indicating that the AGE-PAMAM demulsifier had a greater degree of damage to the emulsion and better demulsification effect.AGE-PAMAM had a dehydration rate of over 70%for emulsions containing KCl and NaCl,and a dehydration rate of over 80%for emulsions with pH=5.4 to 7.0.Through particle size analysis and polarization microscope test,the average particle size of the oil droplets increased from 167.6 nm to about 5000 nm during the demulsification process,indicating that the oil droplets had aggregated.After adding the demulsifier,the zeta potential of the emulsion increased from-40.1 mV to 18.1 mV,and the interfacial tension decreased from 37.841 mN/m to 30.607 mN/m.It was inferred that the demulsification mechanism of the demulsifier was mainly the combined action of the charge neutralization mechanism and the interface membrane replacement mechanism.