Synthesis of nanoporous carbohydrate metal-organic framework and encapsulation of acetaldehyde

Gamma cyclodextrin (gamma-CD) metal organic frameworks (CDMOFs) were synthesized by coordinating gamma-CDs with potassium hydroxide (KOH), referred hereafter as CDMOF-a, and potassium benzoate (C7H5KO2), denoted as CDMOF-b. The obtained CDMOF structures were characterized using nitrogen sorption isotherm, thermo-gravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). High surface areas were achieved by the gamma-CD based MOF structures where the Langmuir specific surface areas (SSA) of CDMOF-a and CDMOF-b were determined as 1376 m(2) g(-1) and 607 m(2) g(-1); respectively. The dehydrated CDMOF structures demonstrated good thermal stability up to 250 degrees C as observed by the TGA studies. XRD results for CDMOF-a and CDMOF-b reveal a body centered cubic (BCC) and trigonal crystal system; respectively. Due to its accessible porous structure and high surface area, acetaldehyde was successfully encapsulated in CDMOF-b. During the release kinetic studies, we observed peak release of 53 mu g of acetaldehyde per g of CDMOF-b, which was 100 times greater than previously reported encapsulation in beta-CD. However, aldol condensation reaction occurred during encapsulation of acetaldehyde into CDMOF-a. This research work demonstrates the potential to encapsulate volatile organic compounds in CDMOF-b, and their associated release for applications including food, pharmaceuticals and packaging. (C) 2016 Elsevier B.V. All rights reserved.