Study On Synthesis,Properties And Application Of Cardanol Sulfonate

To meet the"sustainable"development strategy and the"green chemistry"concept,the surfactant industry is gradually moving toward the development and utilization of safe and environmentally friendly surfactants with excellent overall performance and derived from cheap and renewable raw materials.Cardanol has been proven to be a highly valuable renewable biological resource with low price and wide availability.It has a molecular structure that combines a lipophilic long carbon chain and a hydrophilic active phenolic hydroxyl group,which is expected to replace petroleum phenol and be used to develop green,safe,and low-cost bio-based surfactants.In this work,a biomass anionic surfactant cardanol sulfonate（CDS）,with a similar structure to alkyl benzene sulfonate and excellent comprehensive properties,was synthesized using cardanol as raw material.The surface chemical properties and application properties of CDS were studied,before being mixed with other surfactants and polymers to explore the synergistic effects and interactions of the complex system.Finally,the CDS was applied to the formulation of daily chemicals.The main research contents and results of this study are shown below:Cardanol sulfonate（CDS）was synthesized using cardanol as a raw material,chlorosulfonic acid as a sulfonating agent,and sodium hydroxide as an alkalizing agent.The sulfonation reaction was carried out to introduce sulfonic acid groups onto the cardanol molecule,followed by a neutralization reaction to form the final product.The process involved a single-factor and orthogonal experiment to optimize the conditions,which were determined to be:a molar ratio of 1.3:1 for the reactant chlorosulfonic acid to cardanol,a reaction temperature of 25℃,and a reaction time of 5 hours with trichloromethane as the solvent.The system was neutralized with 10 wt%of sodium hydroxide at low temperature to pH=8～9.The highest sulfonation rate achieved was 99.46%under this optimal condition.The purified product was characterized using FT-IR,MS,and ¹H NMR,which confirmed the formation of the target product.The surface chemical properties and application properties of CDS were also investigated and the application properties were compared with sodium dodecylbenzene sulfonate（SDBS）.The results showed that the Krafft point of CDS was 21.8℃,indicating good water solubility.The critical micelle concentration（cmc）of CDS at 25℃ was 5.13×10^-3mol·L^-1,and the surface tension(γ_cmc)at the critical micelle concentration was 44.40 m N·m^-1.The cmc gradually increased andγ_cmc gradually decreased with the increasing temperature.This also leads to increased adsorption capacity as well as increased efficiency of reducing the surface（boundary）tension at elevated temperatures.The micellization of CDS was a spontaneous exothermic process driven by entropy in the whole studied temperature ranges.Furthermore,the emulsification performance and foam stabilization ability of CDS were better than SDBS,while its wetting performance and foaming ability were slightly worse.However,the decontamination performance of CDS was comparable to SDBS,and its hard water resistance was better.The CDS was mixed with lauramide propyl betaine（LAB）and alkyl glycoside（APG）,respectively.The surface tension,hydrodynamic radius（R_h）,micelle aggregation number（N_m）,and micropolarity of the compound systems were determined by hanging slice method,dynamic light scattering method and steady-state fluorescence probe method.The results showed that both CDS/LAB and CDS/APG systems exhibited non-ideal mixing behavior,indicating mutual attraction between the components.The CDS/LAB compound system has the best synergistic effect when the two components were mixed in a 1:1 molar ratio,corresponding to a cmc of3.06×10^-4 mol·L^-1 and aγ_cmc of 32.60 m N·m^-1.The formation of mixed micelles was a spontaneous exothermic process driven by enthalpy.The CDS/APG compound system at the molar ratio of n（APG）:n（CDS）=9:1 has a more obvious synergistic effect,corresponding to a cmc of 1.13×10^-4 mol·L^-1 and aγ_cmc of 29.10 m N·m^-1.The gradual increase of the molar fraction of CDS（α₁）in the compound system resulted in a gradual decrease in the synergistic effect due to the large difference between the surface properties of CDS and APG.The formation of mixed micelles atα₁=0.1～0.5 was a spontaneous exothermic process driven by enthalpy.The distribution of micelles in the CDS/LAB compound system was wide and unstable due to mutual repulsion and gravitational force,whereas the distribution of mixed micelles in the CDS/APG compound system showed a tendency to concentrate and then converge to a single CDS micelle distribution.The micelle aggregation number（N_m）and application performance of the compound systems were the best at the optimal molar ratio,which confirms the existence of synergistic effect in the compound systems.The interactions between CDS and the neutral polymer PEG and the cationic polymer JR400 were investigated by surface tension,micropolarity and turbidity methods.The results indicated that the interactions between CDS and PEG were weak,while the interactions between CDS and JR400 were strong due to electrostatic interactions.The correlation curves of the CDS-JR400 complex system showed the phenomenon of"three inflection points and double plateau".The addition of inorganic salt Na Cl will have both"salt enhancement"and"salt weakening"effects on the adsorption behavior of the CDS-JR400 complex system.This effect is closely related to the competition between them.Two formulations were prepared using CDS as the active ingredient,namely,concentrated laundry detergent and concentrated laundry detergent with protease.Both formulations were light yellow transparent liquid in appearance,with no odor.All the viscosity,pH and stability test met the standards.The foaming ability and foam stability of both formulations were better than those of the standard laundry detergent and commercially available one.The detergency performance of the concentrated laundry detergent was comparable to that of the standard laundry detergent and commercially available one,while the detergency performance of the concentrated laundry detergent with protease was better than that of the concentrated laundry detergent,and did not show fluctuation with prolonged time and storage conditions.