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Interfacial Physiochemical Properties Of Nonylcyclohexanol Ethoxylate Surfactant And Its Application

Posted on:2021-03-27Degree:MasterType:Thesis
Country:ChinaCandidate:C L RenFull Text:PDF
GTID:2381330611973031Subject:Chemical Engineering and Technology
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For more than 40 years,nonylphenol ethoxylate?NPEOn?,as the second largest amount of non-ionic surfactants in the world,has been widely used in many fields such as pesticides,textiles,detergents and chemical fiber oil agents.However,due to the poor degradability and high biological toxicity of NPEOn,since the 1990s,many countries have banned or restricted the use and production of NPEOn.Therefore,it is necessary to find a green alternative to NPEOn.The nonylcyclohexanol ethoxylates?NCEOn?studied in this paper were designed by replacing the cyclohexyl to the benzyl residue in NPEOn,which could be hypothesized to provide lower biotoxicity and better biodegradability than NPEOn.In this work,the toxicity,interfacial physicochemical properties of NCEOn were evaluated and compared with the NPEO10,AEO,SAE and TO series surfactants,in order to investigate whether NCEOn can solve the ecological safety problem of NPEOn,and whether its performance is close or even better than NPEOn.In addition,the interaction and thermodynamic properties between NCEOn and SDBS molecules were studied.The main contents of this paper are as follows:1.The purification of NCEOn and the effect of its unreacted material and by-products on the interfacial physicochemical properties of NCEOn.The production process of the NCEOn is ethoxylation of nonylcyclohexanol catalyzed by potassium hydroxide,which belongs to the ethoxylation of secondary alcohol.This procedure is prone to remain more unreacted secondary alcohol?NC?and yield more polyethylene glycol?PEG?compared to that of NPEOn production,which would affect the product performance.Therefore,in this work,the industrial NCEOn product was extracted to reduce the PEG and NC content first;and then the impact of PEG and NC on the performance of NCEO9 products were explored by adding different amounts of PEG?0-100%?and NC?0-5%?to the extracted product.The results show that the addition of PEG has no significant effect on the properties of NCEO9,and the addition of a small amount of NC?5%?can greatly reduce the cloud point and foaming power of NCEO9 and improve the wetting properties and emulsifying properties to liquid paraffin of NCEO9.2.Based on a comparative study on fish toxicity,the biotoxicity of NCEOn and its structure-activity relationship were preliminarily evaluated.In order to investigate whether NCEOn has lower biotoxicity than NPEO10,the toxicity of NCEOn?n=7,9,11?and NPEO100 were investigated.The results showed that the biological toxicity of NCEOn to zebrafish embryos decreases with the increase of the EO chain in the molecule:the LC50 values of NCEOn were5.98-7.04 mg/L,which is the 0.81,0.78 and 0.69 folds of that of NPEO10,showing that replacing benzyl with cyclohexyl can indeed reduce the biological toxicity of surfactants.3.Based on a comparative study with other non-ionic surfactants,the physicochemical properties of NCEOn and its structure-activity relationship were investigated.In order to investigate whether NCEOn can perform similar or better physicochemical properties than NPEO10 does,the interfacial physiochemical properties and structure-activity relationship of NCEOn?n=7,9,11?were studied and compared with NPEO10,AEO,SAE and TO series surfactants.The experimental results indicates that with the increase of the EO chain in the NCEOn,the cloud point,critical micelle concentration?cmc?,?cmc,foaming ability and detergency of NCEOn increase,and the emulsifying and wetting capacities decrease.Compared with NPEO10,AEO,SAE and TO series surfactants,NCEO11 has the best cleaning ability on carbon black oil,sebum and protein stains which superior to several other surfactants.And NCEO7 has the best emulsifying performance.The emulsifying ability of NCEO7 for olive oil,liquid paraffin,biodiesel and dimethyl silicone oil is 0.98-1.15 times of NPEO10;And the emulsifying ability to dimethylbenzene of NCEO9 is close to NPEO10.Although the wetting and foaming properties of NCEOn are slightly deficient,but the differences with other surfactants are not obvious.4.Synergistic effect of NCEOn and typical anionic surfactant on interface physicochemical properties.Therefore,based on the aforementioned results,that is,the biotoxicity of NCEOn which is lower than NPEOn and the application performance is close to NPEOn;NCEOn could be expected to become a green substitute for NPEO10 in many application fields.In order to study the application prospect of NCEOn and provide the theoretical support for the application of NCEOn in possible formulations,the anionic surfactant sodium dodecylbenzene sulfonate?SDBS?is selected as the representative surfactant to mix with NCEOn,and the intermolecular interaction and thermodynamic properties is studied using the regular solution theory.The results show that all NCEOn-SDBS systems have synergistic effects on micelle performance,and the strongest synergistic effect on the micelle formation is achieved when?1=0.4-0.6.Yet the interaction between NCEOn and SDBS increases with the increase of the hydrophilic chain of NCEOn.However,in nonane-aqueous solution,the synergistic effect between NCEOn and SDBS decreases with the increase of the EO chain in NCEOn,and the increase of SDBS in the system is conducive to the decrease of interfacial tension.The test of the critical micelle aggregation number and micropolarity proof that the critical micelle aggregation number of all NCEOn/SDBS systems decreases first and then increases with the increase of SDBS.And the micropolarity of the system decreases with the increase of SDBS.
Keywords/Search Tags:nonylcyclohexanol ethoxylates, nonylphenol ethoxylates, application performance, synergistic effect
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