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Intercalation of fatty acids into layered double hydroxides
Dissertation (MSc)--University of Pretoria, 2008.
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University of Pretoria
2013
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| _version_ | 1867613646693072896 |
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| access_status_str | Open Access |
| author2 | Focke, Walter Wilhelm |
| author_browse | Focke, Walter Wilhelm |
| author_facet | Focke, Walter Wilhelm |
| collection | Thesis |
| dc_rights_str_mv | © 2008, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Dissertation (MSc)--University of Pretoria, 2008. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/28361 |
| institution | University of Pretoria (South Africa) |
| last_indexed | 2026-06-10T12:39:27.772Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2013 |
| publishDateRange | 2013 |
| publishDateSort | 2013 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/28361 Intercalation of fatty acids into layered double hydroxides Focke, Walter Wilhelm s26501822@tuks.co.za Nhlapo, N.S. (Nontete Suzan) Layered double hydroxide (LDH) Fatty acids Surfactants UCTD Dissertation (MSc)--University of Pretoria, 2008. Surfactant-mediated intercalation of aliphatic fatty acids into a commercial,layered double hydroxide (LDH) with the approximate composition of [Mg0.689Al0.311(OH2)] (CO3)0.1569nH2O was explored. The reactions were conducted at elevated temperatures with the LDH powder suspended in a fatty acid oil-water emulsion. The acidic fatty acid, e.g. stearic acid, reacts with the basic carbonate anions from LDH-CO3. In the process, CO2 is released as a gas and the fatty acids are intercalated as a bilayer. A high concentration of anionic or non-ionic surfactants, i.e. sodium dodecylsulphate or Tween 60, facilitates the intercalation process by emulsifying the molten fatty acids and dispersing the LDH particles. The presence of carboxylate anions in the interlayer region was confirmed by the carboxylate absorption peaks observed in the region 1700–1000 cm-1 on Fouriertransform infrared spectroscopy (FT-IR). Several bands were observed, i.e. ionised and non-ionised. An increase in the d-spacing of the d003 plane of the brucite-like LDH layers was observed on X-ray diffraction (XRD) analysis of all the LDH intercalates. The d-spacing increased linearly with the length of the carboxylic acid chain. Sharp reflection peaks were obtained on XRD, showing the high crystallinity of the LDH intercalates. The thermal decomposition of these materials was explored on thermogravimetric or differential thermogravimetric analysis (TGA/DTA) and temperature-scanned XRD. The mole ratio of Mg to Al was obtained by XRF and the morphology by scanning electron microscopy (SEM). The present method works well with long-chain aliphatic fatty acids at temperatures above or at the melting point of the desired acid. Temperature proved to be the most important parameter to control during the preparation process, i.e. at low temperatures incomplete reactions were obtained. The method is convenient, economical and environmentally friendly. It employs the readily available carbonate form of LDH as a starting reagent, water is used as medium rather than organic solvents, there are no high-temperature calcinations, and an inert atmosphere is not required. Copyright Chemistry unrestricted 2013-09-07T13:22:28Z 2009-11-05 2013-09-07T13:22:28Z 2009-04-17 2008 2009-10-02 Dissertation Nhlapo, NS 2008, Intercalation of fatty acids into layered double hydroxides, MSc dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://hdl.handle.net/2263/28361 > E1384/gm http://hdl.handle.net/2263/28361 http://upetd.up.ac.za/thesis/available/etd-10022009-193152/ © 2008, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | Layered double hydroxide (LDH) Fatty acids Surfactants UCTD Intercalation of fatty acids into layered double hydroxides |
| title | Intercalation of fatty acids into layered double hydroxides |
| title_full | Intercalation of fatty acids into layered double hydroxides |
| title_fullStr | Intercalation of fatty acids into layered double hydroxides |
| title_full_unstemmed | Intercalation of fatty acids into layered double hydroxides |
| title_short | Intercalation of fatty acids into layered double hydroxides |
| title_sort | intercalation of fatty acids into layered double hydroxides |
| topic | Layered double hydroxide (LDH) Fatty acids Surfactants UCTD |
| url | http://hdl.handle.net/2263/28361 http://upetd.up.ac.za/thesis/available/etd-10022009-193152/ |