Synthesis And Application Of Novel Acid Functionalized Ionic Liquids

Green chemistry has been the research focus currently, which applies innovative scientific solution to real-world environmental situation. However, the use and generation of hazardous and volatile substance in current chemical processes and industrial production is contrary to the concept of green chemistry from beginning to end. In recent years, the ionic liquids, as a new type of reaction solvent or catalyst, presenting many unique physical and chemical properties, such as non-flammable, tunable acidity, high thermal stability and recyclability, has been widely concerned in organic chemistry, materials chemistry, electrochemistry, polymer chemistry, analytical chemistry, as well as separation and purification technology, and many other fields. With the deepening of theoretical research on ionic liquids and the rapid development of applied technology, It’s necessary to design and develop more novel ionic liquids with special function to meet requirement of different areas.In this study a series of dual-core Brφnsted acidic ionic liquids containing imidazole and pyridine cations were designed and synthesized in the aim of developing new functional ionic liquids with prospect application. Seven novel functional ionic liquids including [SO3-pmim][HSO4]、[mim]2C4[HSO4]2and [mim]2C3[HSO4]2、[mim]2C5[HSO4]2[mim]2C6[HSO4]2、[BPy]2C3[HSO4]2、[BPy]2C4[HSO4]2have been synthesized. Their structures were characterized by the FT-IR,’H-NMR. These ionic liquids were then used them as catalysts for transesterification of waste oil to biodiesel and catalyzed hydrolysis of soybean isoflavone glucosides of natural products to prepare soybean isoflavone aglycone. They have been proved to be effective catalysts for transesterification and hydrolysis. This will expand the further application of ionic liquids in catalysis processes.Studies on the waste oil indicated that these acidic ionic liquids performed good catalytic activity in the process of catalyting transesterification of waste oil to biodiesel.The ionic liquid [mim]2C3[HSO4]2has the highest catalytic activity.Thus for the following experiments,[mim]2C3[HSO4]2was used as catalyst.According to the single factor and orthogonal design, four factors including mole rate, time, temperature and dosage of ionic liquid were examined, meanwhile we studied the stability of ionic liquid for reuse. The optimal conditions of the synthesis of biodiesel with catalytic transesterification were methanol:oil=45:l,reaction temperature170℃, time2h and catalyst(8%,wt%).Under the optimal conditions,the biodiesel conversion could reach to95%.And the ionic liquid has good stability,the catalytic activity didn’t dcrease obviously after recycling6times.Acidic ionic liquids performed good catalytic activity for the hydrolysis of soybean isoflavones.Results showed that the ionic liquids of [mim]2C4[HSO4]2has the highest catalytic activity. By single factor design, Three factors of ionic liquid concentration, time, temperature were examined. The results showed the condition should be catalyst dosage1mmol/mL,reaction temperature95℃and time3h. Under the optimal conditions, yield of daidzein could reach to95.9%. and the optimum hydrolysis conditions of genistin show that catalyst dosage1mmol/mL,reaction temperature100℃and time3h. Under the optimal conditions, yield of genistein could reach to92.3%.Otherwise, Study on the recycled ionic liquid showed that after6cycles catalytic activity of ionic liquid has no significant change.