Synthesis Of 2-ethylhexyl Glucoside And Its Grinding Aid Properties

With the continuous improvement of human environmental awareness,the development of new green surfactants has received extensive attention.Alkyl glycoside?APG?is a new type of green nonionic surfactant produced by dehydration condensation of naturally renewable sugars and fatty alcohols under acidic catalysis.APG products have been applied to many fields such as daily chemicals,phar-maceuticals,petrochemicals,metallurgy,etc.in recent years due to their good compatibility,small human stimulation,environmental friendliness and biodegrad-ability.In this study,2-ethylhexyl glucoside?isomeric alkyl glycoside,APG-IC8?was synthesized by direct glycosidation using anhydrous glucose and 2-ethylhexanol?isooctanol?as raw materials.Dodecylbenzenesulfonic acid?DBSA?as the main catalyst was optimized,and the mixed acid prepared had better catalytic effect than the single acid DBSA with shorter reaction time.The self-made mixed acid was selected as the catalyst,and the catalyst addition amount,the alcohol sugar ratio,the reaction temperature and the reaction pressure were taken as the investigation targets,and the time required for the reaction,the polymerization degree of the reaction product and the transparency?side reaction?were taken as indicators.The single factor influence experiment results of the glycosidation reaction show that the higher the reaction vacuum degree,the shorter the reaction time required;Under the condition of vacuum degree 0.07?0.08 MPa,the preferred process parameters are:temperature 95?,catalyst dosage is 3%of glucose mass,molar ratio of alcohol to sugar is 5:1,and APG-IC8 yield is 156%,the reaction time was 10 h,the average degree of polymerization was 1.3,and the product transparency and color were good.Response surface optimization experiment design takes self-made mixed acid as catalyst,reaction temperature,molar ratio of alcohol and sugar,catalyst dosage as interactive influencing factors.The box-behnken central combined response surface method was established with the optimal parameters obtained by the single factor influence experiment as the central value.Optimize validation results show that in the vacuum degree is 0.08?0.09 MPa,the reaction temperature is 98?,alcohol sugar,mole ratio of 5.24:1,catalyst dosing amount is 3.63%of the quality of glucose,reaction time needed for 6.7 h,APG-IC8 production rate was 162%,the average degree of polymerization is 1.51,the product transparency and color are good.The infrared spectrum analysis of the synthesized products showed that the C-O-C stretching vibration peak with asymmetric ether at 1250 cm^-11 and 1030 cm^-1was the characteristic absorption peak of glycosides.After derivatization,the retention time of the product was consistent with that of the 2-ethylhexyl glucoside gas chromatogram,and it could be determined as the target product APG-IC8.The results of performance studies show that the surface tension of APG-IC8 decreases with increasing temperature.The surface tension is 29.0 mN/m at 20?,and the criti-cal micelle concentration?CMC?is 0.046%,It belongs to a kind of alkyl polyglycosides non-ionic surfactant with high activity,low foam type and strong emulsifying ability;It can be compounded with typical cationic,anionic and nonionic surfactants in any proportion to achieve synergistic effect.The pH,color,solid content and sulfated ash content of the self-made APG-IC8 product all meet the requirements of the standard grade I alkyl glycosides.Grinding is a high energy consumption and high material consumption section in the industrial production of alumina.Adding grinding aids is conducive to energy saving.In this study,the self-made APG-IC8 was applied to the simulation of the grinding of bauxite for the first time.When the grinding aid was not added:the grinding effect was the best when the mass ratio of the ash was 10%,the grinding time was 20 min,and the rotation speed was 100 r/min;Under the same grinding conditions,adding a certain amount of APG-IC8 as grinding aid has obvious grinding effect on the slurry with a solid-liquid ratio of 1.27,1.50 and particle size of d1?3mm bauxite,the particle content in the slurry with particle size?63?m can be increased by 6.29%compared with the blank;Infrared spectroscopy and scanning electron microscopy analysis showed that APG-IC8 adsorbed on the surface of bauxite particles and the surface roughness decreased.Thermogravimetric analysis showed that the glycoside was thermally decomposed by about 10%at 260?,and a large amount of pyrolysis at 360?.In summary,the addition of APG-IC8 is helpful for grinding,but the impact on the alumina melting and decomposition section needs further study,This study can provide basic data for future applications in industrial production.