Significant Heterogeneous Carbonate Salt Catalyzed Acetylation of Alcohols via a Transesterification Process with Carbonate Salt-activated Alcohol ¹ H NMR Evidence

Abstract

Heterogeneous carbonate salt catalyzed acetylation of alcohols via a transesterification process has been developed. Various esters are furnished up to 97% yield. Established procedure is simple and air-tolerant with readily available reagents. Ethyl acetate and isobutyl acetate are used as not only acetylating agents, but also reaction solvents in transesterification. Aliphatic linear alcohols, allylic alcohols and benzyl alcohols show high reactivities in the presence of 1 or 5 mol% Cs 2 CO 3 at 125 ℃. Cesium carbonate can be recycled by pumping liquid phase out of reactor after reaction. During four cycle runs for reaction of 2-phenylethanol and ethyl acetate, high yields of phenethyl acetate are provided (＞60% yield). Based on experiments and 1 H NMR investigation, bifunctional catalysis is proposed, alcohol activated by carbonate ion is confirmed, and higher activity of catalytic amount than stoichiometric cesium carbonate is interpreted.

Preconcentration of Synthetic Phenolic Antioxidants in Instant Noodle Samples by Alcohol-Based Vortext-Assisted Liquid-Liquid Microextraction and Determination by High-Performance Liquid Chromatography

“…Reversed-phase HPLC provides high selectivity for the separation of synthetic antioxidants under chromatographic conditions [4][5] . Other methods including thin-layer chromatography (TLC) 6 , gas chromatography (GC) 7 , GC-MS 8,9 , gas liquid chromatography (GLC) 10 , micellar electrokinetic capillary chromatography 11 and spectrophotometry 12 have also been used for determination of synthetic phenolic antioxidants.…”

Highly Diastereoselective [3 + 2] Cycloaddition of Aziridines with Difluorinated Silyl Enol Ethers: Divergent Synthesis of 4,4-Difluoropyrrolidines and 4-Fluoropyrroles

“…Then, in the presence of Cs 2 CO 3 , lactone III was generated. 20 The subsequent decarboxylative/dehydrofluorinative aromatization 11d of intermediate III delivered product 8.…”

“…The following nucleophilic attack of C­(α) in difluorinated silyl enol ether 2a at the N –Ts iminium carbon formed the difluoroalkylated intermediate II , which underwent a subsequent intramolecular aldol process to led to the formation of product 3a and the regeneration of catalyst Sc­(OTf) 3 . Then, in the presence of Cs 2 CO 3 , lactone III was generated . The subsequent decarboxylative/dehydrofluorinative aromatization of intermediate III delivered product 8 .…”

Ethyl acetate as an acetyl source and solvent for acetylation of alcohols by KOH

“…The substrates containing halogen substituent also gave excellent yield of according products while no dehalogened compounds were produced (Table 3, entries 8-12). For the substrates with various electron-withdraw group (-CF 3 or -NO 2 or -CN or -C^C) also could be smoothly reacted under the standard condition, giving 87%, 83% and 84% yield of the desired products, respectively (Table 3, entries [13][14][15][16]. In which, the -CN and -C^C groups could be tolerated under the reaction condition.…”

“…The metal-based catalysts including dilithium tetra- tert -butylzincate (TBZL), 8 LiClO 4 /In(OTf) 3 , 9 Y 5 (O i Pr) 13 O, 9 ZrCl 4 -Mg(ClO 4 ) 2 , 10 CoCl 2 ·6H 2 O, 10 heterogeneous zinc/imidazole, 11 Zn 4 (OCOCF 3 ) 6 O, 12 InI 3 /I 2 , 13 Zn reagent. 14 And some transesterification of alcohols under metal-free conditions were reported, such as Cs 2 CO 3 , 15 I 2 , 16 KO t Bu, 17 K 2 CO 3 , 18 Novozyme-435, 19 TsOH, 20 ( Table 1 ).…”