| Titre : |
Superheated alcohols : lipids from plants |
| Type de document : |
texte imprimé |
| Auteurs : |
Tony Clifford, Auteur |
| Année de publication : |
2014 |
| Article en page(s) : |
p. 26-27 |
| Note générale : |
Bibliogr. |
| Langues : |
Anglais (eng) |
| Catégories : |
Alcool
Extraction (chimie)
Extraits de plantes:Extraits (pharmacie)
IsopropanolL'isopropanol ou alcool isopropylique est le nom commun pour le propan-2-ol, composé chimique sans couleur et inflammable dont la formule chimique est CH3CH(OH)-CH3. C'est l'un des deux isomères du propanol (l'autre étant le propan-1-ol). Il est aussi connu sous son nom abrégé IPA (acronyme de l'anglais IsoPropyl Alcohol). Il est obtenu à partir de la réduction de l'acétone par le tétrahydruroborate de sodium.
Un autre procédé de fabrication consiste en une hydratation indirecte du propylène par l'acide sulfurique à 70 %, suivie d'une hydrolyse qui conduit à l'isopropanol.
|
| Index. décimale : |
668.5 Parfums et cosmétiques |
| Résumé : |
Superheated alcohols are liquid alcohols under pressure above their boiling points. They are much less polar than they are at room temperature. As a result they can extract lipid materials from biomass. This is often carried out by industrial organic solvents such as hexane. Instead the extraction can be carried out using benign solvents, both from the point of view of the environmental impact and solvent residues in the product. In addition novel compounds of interest can be obtained from a particular biomass. The motivation behind this development was to find environmental solvents, which can extract lipid materials from plant materials. We have experience using superheated water (lqiquid water under pressure above 100 °C) and wrote an article for Personal Care in February 2012. Molecular association by hydrogen bond increases the polarity of a solvent. This is particular the case in liquid water where there is an extensive intermolecular structure. When water is heated, this hydrogen-bond structure breaks up causing a reduction in polarity as measured by the dielectric constant strictly called nowadays the relative permeability. We will call it here by the older term: dielectric constant. The dielectric constant of water is 78 at room temperature and falls to 35 at 200°C. This enables it to dissolve organic molecules if they are slightly polar or polarizable. However, it will not dissolve completely non-polar molecules. We therefore decided to carry out research on superheated alcohols. Alcohols from dimers by hydrogen bonding and these break up at about 125 °C. The break-up of hydrogen bonding is also expected to cause the polarity of ethanol and other alcohols to fall in this temperature region. Thus we would expect some anomalous behaviour in the dielectric constant of alcohols in the region 100 °C to 150 °C. |
| Note de contenu : |
- System for measurement of the dielectric constant
- Dielectric constant of ethanol
- Dielectric constant of isopropanol
- Laboratory and pilot-scale experimental studies |
| En ligne : |
https://drive.google.com/file/d/1RSRM7KUpjv7gfMUACx4LP1JQhw9r68dR/view?usp=drive [...] |
| Format de la ressource électronique : |
Pdf |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=22013 |
in PERSONAL CARE EUROPE > Vol. 7, N° 5 (09/2014) . - p. 26-27
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