Study On The Application Of Ionic Liquids In The Extraction Of Natural Products

Rose essential oil has been widely used in medicine,pharmacy,food and cosmetics.The terpenoids and alcohol compounds are still rich in the rose dregs produced in industrial process.The rose dregs are usually used as agricultural fertilizers or fuels,which can lead to the waste of resources.In order to improve the effective utilization rate of rose resources,it is particularly important to extract rose essential oil from rose dregs.The methods of extracting rose essential oil include steam distillation,ultrasonic extraction,molecular distillation technology,supercritical CO₂ extraction,microwave extraction,and organic solvent extraction.The method of extracting essential oil from rose has been deeply studied,nevertheless the report of extracting rose essential oil from rose dregs are few.On the purpose of improve the utilization rate of rose and reduce the price of rose essential,the rose dregs can used as raw material to extract essential oil.In this study,firstly,organic solvent was used to extract the rose essential from rose dregs.The gas chromatography-mass spectrometry was also applied to analyze the component of rose essential oil,and the extracting condition was optimized.The best extracting condition were as follows:petroleum ether was optimal extracting agent,the ratio of material to liquid was 1:3,reflux time was 4 hours,and distillation temperature was 80?,and in the optimized condition the extraction rate of rose essential oil was up to0.5714%.Citronellol,geranium acetate,the main components of rose essential oil,were present in the product.After determined the ability of scavenging hydroxyl radicals,its ability of scavenging hydroxyl radicals was similar to that of gallic acid.Secondly,several types of ionic liquids(choline chloride ionic liquid,betaine ionic liquid and tetrabutylammonium bromide ionic liquid)were used as solvent in this study,and the tetrabutylammonium bromide-propionic acid ionic liquid was selected as the best solvent.Five factors(feed-liquid ratio,extraction temperature,reflux time,stripping agent amount and repeated extraction times)were considered in the reaction.The results showed that the optimum process conditions were 1:4 mass ratio of material to liquid,the temperature 75?,reflux time 4 hours,and the amount of stripping agent 80 g.The extraction effect did not show obvious decline after repeating extraction for three times.Compared to other organic solvents in the yield,solvent consumption and extraction time,using tetrabutylammonium bromide-propionic acid ionic liquid can effectively reduce energy consumption and reduce environmental burden,which proves that the technology is sustainable.At last,the surface molecularly imprinted polymer was synthesized with silica gel as a carrier,1-vinyl-3-carboxymethyl imidazole chloride as functional monomer and geranyl acetate as a template.The results showed that when KH-570 was used as coupling agent,the reaction temperature was 75?,the molar ratio of geranyl acetate to the crosslinking agent was 1:18,the surface molecularly imprinted polymer had the best adsorption capacity for geranyl acetate.The adsorption model accords with the Langmuir model,and the adsorption kinetics was quasi second order.The equilibrium adsorption was 487.24mg/g,the maximum adsorption capacity was 588.29 mg/g,and the adsorption capacity did not decrease significantly after six times of reuse.Geranyl acetate was isolated from rose pomace by using this surface molecularly imprinted polymer,and the similarity with the pure product was more than 99%.