Synthesis Of Deep Eutectic Solvents And Its Application In Esterification Reaction

In the increasingly modern chemical production,volatile organic solvents participate in chemical reactions or as liquid media in the extraction process have attracted more and more attention,because these organic solvents have caused tremendous damage and threat to the ecological environment for the safety of human beings and other organisms.Minimum use of these substances harmful to human living environment has a prominent significance for the development of human society and even economic benefits.The best way to solve this problem is to consider good treatment measures before designing and manufacturing products and before finalizing the initial design and synthesis methods,instead of waiting for pollution to be treated,then modifying to re-polluted,and also to control this vicious circle,which is also the most basic principle of green environmental protection vigorously advocated since the21st century.In order to achieve this goal,it is extremely urgent to find effective green alternatives that do not harm the human environment.Deep eutectic solvents?DESs?,as a kind of greener and environmentally friendly solvents compared with ionic liquids?ILs?,have many advantages,such as low vapor pressure,low toxicity,degradability,readily available raw materials,simple synthesis,simple separation of reaction products,wide solubility,excellent electrochemical performance,etc.Therefore,DESs have good performance in many fields.Application prospect.Choline chloride is a relatively economical,non-toxic and biodegradable quaternary ammonium salt.It belongs to one of the B vitamins.Some of them can be extracted directly from existing organic biomass and can be synthesized by chemical methods,such as trimethylamine and ethylene oxide.Gas-phase reaction of alkane with hydrochloric acid.Choline chloride is rich in sources,widely used,non-toxic and environmentally friendly.Choline eutectic solvents?DES?can be obtained by simply mixing choline salts with ligands.Firstly,different types of cryogenic eutectic solvents were synthesized as catalysts for DES,and then working curves were drawn.Then different types of DES were used to catalyze the esterification of acetic acid with n-butanol.It was found that the cryogenic eutectic[ChCl][CrCl₃ 6H2O]₂ formed by choline chloride?ChCl?and chlorination hexahydrate?CrCl₃ 6H2O?had the highest catalytic efficiency.The esterification rate reached 92.97%by GC analysis.It was confirmed that[ChCl][CrCl₃6H2O]₂ was used as DES catalyst as the research object,and different reaction conditions were changed,such as the molar ratio of catalyst,feed ratio of reactants,reaction temperature,reaction time,number of catalyst recovery,etc.After optimizing the reaction conditions,determining the catalyst and catalytic reaction conditions,and combining with some previous experimental methods,a comparative experiment and enlarged experiment were carried out.The conversion rate reached more than 90%.The innovative experimental method was basically realized.Finally,it was applied to various esterification reactions,and the esterification reaction of different alcohols with acetic acid was studied.It was found that[ChCl][CrCl₃ 6H2O]₂ as DES catalyst has very high catalytic activity,the synthesis is very simple and easy to obtain,and the cost is low,with good economic benefits.