A Novel Synthesis Technology of Ethyl-β-Cyclodextrin

Gan Yongjiang,Zhang Yimin,Zhang Bei,Ling Shanfeng

doi:10.11648/j.sjc.20210903.12

Abstract

A novel green synthesis process about ethyl-β-Cyclodextrin have been investigated through the reaction between β-cyclodextrin and diethyl carbonate by used anhydrous potassium carbonate as catalyst in DMF. The influence of experimental factors including reaction time, the molar ratio of β-cyclodextrin to diethyl carbonate, reaction temperature and contents of anhydrous potassium carbonate on the average degree of substitution of ethyl-β-cyclodextrin were carried out by a design method of orthogonal experiments. The results shown that the average degree of substitution of ethyl-β-cyclodextrin can be depend on the reaction temperature and the molar ratio of raw material primarily. The optimal maximum average degree of substitution of ethyl-β-cyclodextrin is 6.0 when the molar ratio of β-cyclodextrin to diethyl carbonate, reaction temperature, reaction time and dosage of catalyst are 1:28, 120°C, 24h and 2.0 g, respectively. The structures of ethyl-β-cyclodextrin were characterized by TLC, IR, MS, <sup>1</sup>H-NMR and <sup>13</sup>C-NMR, and these results are concordant with former ones which synthesized ethyl-β-cyclodextrin by diethyl sulfate or ethyl iodide.

Highlights

Gan Yongjiang et al.: A Novel Synthesis Technology of Ethyl-β-Cyclodextrin research is focused on the need for less hazardous and more effective ethylation regent to replace diethyl sulfate and ethyl iodide
Materials were purchased from Kewei Company of Tianjin University, China. β-CD was re-crystallized and dried before use under vacuum at 80 °C, anhydrous potassium carbonate, Diethyl carbonate (DEC), DMF, acetone, acetonitrile, ethyl acetate, ammonia water, and ether directly used without further treatment
A green synthesis of ethyl-β-CDs is described via DEC and β-CD

Summary

General Methods

FT-IR spectra of the samples pressed with KBr in the framework region (400–4000 cm−1) were recorded at room temperature with a MAGNA-IR 560 spectrometer. Mass spectra were determined on an LCQ Advantage MAX spectrometer (ESI). NMR spectra (1H, 500.13 MHz; 13C, 125 MHz) were recorded on a Varian INOVA 500 MHZ instrument. 30 mg of sample was directly dissolved into the NMR tube in 0.6 mL of solvent. 1H and 13C NMR spectroscopic data were recorded for solns in DMSO, using a Jeol GSX-500 or Jeol JNM-ECP 500 spectrometer (1H: 500 MHz, 13C: 125 MHz). Materials were purchased from Kewei Company of Tianjin University, China. Reactions were monitored by thin-layer chromatography (TLC) on a precoated plate of silica gel 60 F254 (layer thickness 0.2 mm; Haiyang, Qingdao, China) and detection by iodine vapor

General Procedure Ethyl-β-CDs

Results

MS Analysis

Conclusion