Synthesis And Online FTIR Spectrophotometric Investigation Of Novel Asphalt Emulsifiers

A novel cationic asphalt emulsifier, a betaine-type asphalt emulsifier and a modified lignin amine were synthesized in this paper. The optimum reaction conditions were obtained by the investigation of various factors that influenced the reaction yield. The synthesis process was monitored by online FTIR technique. The chemical structure of the product was confirmed by FTIR,1H NMR and elemental analysis. The performance tests of emulsifiers were investigated in the mixing text.A novel cationic asphalt emulsifier N,N-dimethyl-N-(oxiran-2-ylmethyl)octadecan-l-aminium chloride was synthesized by the reaction of epichlorohydrin and N,N-dimethyloctadecylamine. The optimum reaction condition was obtained. The reaction yield reached98.0%at the optimum conditions of reaction time5h, reaction temperature50℃, feedstock mole ratio of epichlorohydrin to N,N-dimethyloctadecylamine1.2. The chemical structure of the product was confirmed by FTIR,1H NMR and elemental analysis. The synthesis process was monitored by online FTIR technique. The by-product was detected by the online FTIR analysis. Based upon the experimental data, a plausible reaction mechanism was proposed for the reaction. The CMC of the emulsifier has a lower value of4.35×10-4mol/L. The surface tension at CMC is28.51mN/m. The emulsifier has satisfactory emulsification. The prepared bituminous emulsion showed higher storage stability. The emulsifier belongs to medium-set asphalt emulsifier.A novel betaine-type asphalt emulsifier3-(N,N,N-dimethyl acetoxy ammonium chloride)-2-hydroxypropyl laurate was synthesized after three steps by the reaction of epichlorohydrin, lauric acid, dimethylamine and sodium chloroacetate. The optimum reaction conditions were obtained for the synthesis of the first step of3-chloro-2-hydroxypropyl laurate. The esterification yield reaches97.1%at the optimum conditions of reaction time6h, reaction temperature80℃, feedstock mole ratio of epichlorohydrin to lauric acid1.5, mass ratio of catalyst to lauric acid2%. The structures of the three products were identified by FTIR. The first synthesis step of3-chloro-2-hydroxypropyl laurate was monitored by online FTIR technique. The by-product was detected by the online FTIR analysis. Based upon the experimental data, a plausible reaction mechanism was proposed for the reaction. The CMC of the objective product has a lower value of7.4×10-4mol/L. The surface tension at CMC is30.85mN/m. The emulsifier of the objective product has excellent emulsifying ability to asphalt. The prepared bituminous emulsion showed higher storage stability. The emulsifier belongs to a rapid-set asphalt emulsifier.A novel cationic asphalt emulsifier of tetraethylenepentamine/formaldehyde modified lignin amine was synthesized by tetraethylenepentamine, alkali lignin and formaldehyde. The optimum reaction condition was obtained. The yield reaches50.88%at the optimum conditions of the amount of lignin32g, the amount of tetraethylenepentamine0.1mol, mass ratio of NaOH to lignin2.15%, feedstock mole ratio of formaldehyde to tetraethylenepentamine2.0, reaction time2.5h and reaction temperature80℃. The structure of the target product was identified by FTIR. The synthesis process was monitored by online FTIR technique and the intermediate was detected. Based upon the experimental data, a plausible reaction mechanism was proposed for the reaction. The target product has good surface activity and satisfactory emulsification effect. The prepared bituminous emulsion showed higher storage stability. The emulsifier belongs to slow-set asphalt emulsifier.