Synthesis And Application Of New Surfactants Of Hydroxy-ethylenediphosphonic Acid Homologues

In the first part of this paper,the hydroxyl value of industrial fatty alcohol polyoxyethylene ether（AEO-n,n=3,5,7,9,10,15）was measured and its average molecular weight was corrected.Then,AEO,sodium chloroacetic acid and Na OH were used as raw materials and ethanol was used as solvent.A series of fatty alcohol polyoxyethylene ether carboxylate sodium（AEC-n,n=3,5,7,9,10,15）was synthesized by carboxymethylation,and then dodecyl epoxide carboxylic acid（AEC-COOH-n,n=3,5,7,9,10,15）was synthesized by hydrochloration.After characterization of the intermediate product,the homolog of hydroxy-ethylenediphosphonic acid-series dodecyl epoxyldiphosphonic acid（AEDP-n,n=3,5,7,9,10,15）was synthesized by phosphorous trichloride-hydrolysis method with xylene as solvent and the optimum process conditions of the reaction were determined.The acyl chlorination reaction temperature was 115℃and the reaction time was 2 h.The hydrolysis temperature was 80℃and the reaction time was 0.5h.The synthetic yield was up to67.1%.The product was characterized by infrared spectroscopy and hydrogen NMR spectroscopy to determine the synthesis of target products.In the second part,the critical micellar concentration,surface tension,temperature and salt resistance,emulsification and foaming property,wettability and other surface properties of the synthesized series AEDPs were tested,and the influence of EO group number on the surface properties was explored.The critical micellar concentration（cmc）of six AEDPs was determined by platinum ring method.The cmc values were between 1.95×10^-4mol/L and 1.01×10^-4 mol/L,and the number of EO groups was directly related to cmc values.The larger the number of EO,the smaller the cmc.In addition,a series of experiments have been conducted to explore the influence of EO group on other surface properties.The results show that the increase of EO number decreases the emulsifying power,and the foam and wettability are worse.Overall,AEDP-3 has the best performance as a conventional surfactant.By simulating high temperature and hard water conditions,the temperature and salt tolerance of AEDPs under harsh conditions were tested.By analyzing the slope of gamma-t curve,it can be seen that the critical micellar concentration and surface tension of AEDPs with more EO number changed less with temperature,and the AEDPs were more stable at high temperature and had better temperature resistance.The results of salt tolerance test showed that AEDP-15 had the best salt tolerance,and the tolerance concentration of Na⁺was 160mg/L,and the tolerance concentration of Ca²⁺was up to 260mg/L,and the tolerance ability of AEDP-n to Ca²⁺was greater than that of Na⁺.In the third part,the properties of a series of AEDPs as scale inhibitor and corrosion inhibitor are tested,in which the phosphate base group plays a leading role.In terms of scale inhibition,EDTA titration was used to evaluate its scale inhibition performance.The results show that EO number affects molecular scale inhibition performance,and the scale inhibition rate is A-3>A-5>A-7>A-9>A-10>A-15,showing A trend of decreasing scale inhibition performance with the increase of EO number.Except for the low concentration of A-15,the scale inhibition rate of AEDP is higher than that of HEDP under the same conditions.Scanning electron microscopy directly shows that the addition of AEDP changes Ca CO₃ crystal from dense calcite to irregular aracharite,spheroarazite and snowflake deposits,resulting in the fracture of Ca SO₄ crystal growth,indicating that series AEDPs have excellent scale inhibition/inhibition performance.In addition,AEDP also has a certain corrosion inhibition ability,which is realized through the two principles of intermolecular adsorption plating protective film and weakening the reaction of battery in water with complexing Fe²⁺.The experimental results show that the influence of EO number on corrosion inhibition performance shows that the more EO group number,the stronger the intermolecular force and the better the corrosion inhibition effect.