Synthesis of alcohol ester 12 in 1, 8‐diazabicyclo [5.4.0] undec‐7‐ene (DBU)‐based Self‐separation catalytic system

Abstract

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.

Degradation of Poly(ethylene terephthalate) Catalyzed by Nonmetallic Dibasic Ionic Liquids under UV Radiation

“…The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/ma17071583/s1, Figure S1: FT-IR spectrum of [HDBU][Im] [35,50,51]; Figure S2: 1 H NMR spectrum of [HDBU][Im] [34,52]; Figure S3: 1 H NMR spectrum of BHET [16]; Figure S4: HPLC spectrum of BHET; Figure S5: TGA curves of PET raw material and BHET [16]; Figure S6: DSC curves of BHET [21]; Figure S7: FTIR spectrum of BHET [22,40,53]; Figure S8: The TGA curve of [HDBU][Im]; Figure S9: FT-IR spectra of DBU/EG mixtures; Table S1: The changes in PET crystallinity during the degradation reaction [54][55][56][57][58].…”

Synthesis of 2, 2, 4‐trimethyl‐1, 3‐pentaerediol monoisobutyrate catalyzed by homogeneous catalysis‐liquid/liquid separation catalytic system based on Bibasic sites Ionic Liquids

“…[3][4][5] More recently, we reported a kind DBUfunctionalized monbasic site ionic liquids (MSILs) with a room temperature ILs/H 2 O-IBD phase transition characteristic. [6,7] The MSILs catalyst system can be recycled for 5 times, and the yield of CS-12 is 66.17%. [[8] This has been touched on to provide potential insights for higher alkaline density and structural strength bibasic sites ionic liquid (BSILs) by modification of cations and anions to bind specific functional group.…”