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

Abstract

Gamma cyclodextrin (CD) metal organic frameworks (CDMOFs) were synthesized by coordinating γ-CDs with potassium hydroxide (KOH), referred hereafter as CDMOF-a, and potassium benzoate (C 7 H 5 KO 2), 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 γ-CD based MOF structures where the Langmuir specific surface areas (SSA) of CDMOF-a and CDMOF-b were determined as 1,376 m 2 .g-1 and 607 m 2 .g-1 ; respectively. The dehydrated CDMOF structures demonstrated good thermal stability up to 250 o 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 μg of acetaldehyde per g of CDMOF-b, which was 100 times greater than previously reported encapsulation in β-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 CDMOFb, and their associated release for applications including food, pharmaceuticals and packaging.

Role of package headspace on multilayer films subjected to high hydrostatic pressure

“…White spot and transparent film colour values ( L *, a *, b *) were measured using a colorimeter (Minolta CR 200, Konica Sensing America Inc., Ramsey, NJ). Lightness ( L *) values of the white spots and the pouch were also compared with a white standard printing paper (lightness value was 92), illustrating the severity of the process on the transparent packages . The film thickness of unprocessed and processed pouches and at white spot defects were measured using an electronic disc micrometer (model 15769, Flexbar Machine Co. Islandia, NY).…”

Stability and Phase Transitions of Nontoxic γ-Cyclodextrin-K+ Metal-Organic Framework in Various Solvents

“…According to the DSC curves, the onset temperatures of decomposition are as follows: T δ = 270 • C, T ε = 292 • C, and T α = 275 • C (however, the exact limits of the heat flow peak are difficult to define). The weight loss for εand α-phases is 48%-49% and 42% for δ-phase, and it can be related to the elimination of hydroxyl groups present in γ-CD and further destruction of glucose units [29][30][31][32]. The decomposition of δ-phase occurs at a higher temperature compared to that of εand α-phases.…”

Metal‐Organic Coordination Polymers Formed from γ‐Cyclodextrin and Divalent Metal Ions

“…Metal‐organic frameworks (MOFs) formed from cyclodextrins (CDs) and alkali metal ions have been widely described in the literature . The functional properties of CD‐MOFs obtained from γ‐cyclodextrin and alkali metal hydroxides have been studied in detail for a number of applications , . For example, the framework obtained from RbOH and γ‐CD has a high specific surface area and an exellent sorption capacity for carbon dioxide,, and it demonstrates a considerable decrease in its conductivity upon CO 2 sorption .…”