Synthesis of alcohol ester 12 in 1, 8-diazabicyclo [5.4.0] undec-7-ene (DBU)-based Self-separation catalytic system
The synthesis of alcohol ester 12 is one of the valuable industrial processes, but it was impeded by poor separating property and recycling ability of the catalytic systems. Herein, four novel DBU-based basic ionic liquids (DBILs) of [BDBU]IM, [BDBU]OH, [ODBU]IM, [[ODBU]OH were synthesized successfully by introducing the alkyl chains of 1-bromobutane or 1-bromooctane to 1,8-diazabicyclo [5.4.0] undec-7-ene (DBU), and then, employing imidazole (IM − ) or hydroxide (OH − ) as counter ions. The above obtained four ionic liquids were applied in the synthesis of alcohol ester 12 in isobutyraldehyde (IBD)/aqueous media for the first time. Interestingly, after reaction, production of alcohol ester 12 can be self-separated from ionic liquids/water (ILs/W) catalytic system automatically. Furthermore, the self-separated ILs/W can be recycled and used in next catalytic reaction for at least 5 times without obvious loss of catalytic performance. In this work, the structure, purity, thermal stability and alkalinity of DBILs were characterized systematically. [BDBU]IM shows high alkalinity and thus enhances yield of 66.17%. From thermo gravimetric analyzer (TGA), [BDBU]IM also exhibits excellent thermal stability. So [BDBU]IM was chosen for the further studying. Furthermore, quantum chemistry is applied to calculate the interaction forces and electron energies of reactants by DFT, and the calculation results illustrate the feasibility of synthetic process of DBILs. The self-separation strategy of DBILS in this work may open up a new avenue for the clean synthesis of other industrial products.
危险品化学品经营许可证（带存储）