Membrane-based processes for selectively fractionating essential oils

Patent metadata

Field	Value
Publication number	US-10934501-B2
Application number	US-201816209009-A
Country	US
Kind code	B2
Filing date	Dec 4, 2018
Priority date	May 7, 2012
Publication date	Mar 2, 2021
Grant date	Mar 2, 2021

Abstract

The present disclosure in general relates to a process for (1) reducing impurities, i.e. undesirable natural components such as waxes and undesirable synthetic materials such as agrochemicals and other environmental pollutants, or (2) fractionation of natural components present in an essential oil using at least one selective membrane.

First claim

The invention claimed is:

1. A process for separating components in an essential oil, comprising:
providing an essential oil or a solution comprising an essential oil and at least one organic solvent as a nanofiltration feed, wherein
the essential oil is obtained from a natural raw material of plant origin by a process chosen from:
a) steam distillation followed by separation of the aqueous phase, if any, by physical processes,
b) mechanical processes from the epicarp of Citrus fruits followed by separation of the aqueous phase, if any, by physical processes,
c) dry distillation followed by separation of the aqueous phase, if any, by physical processes,
d) mechanical expression from a natural raw material of plant origin other than Citrus fruits,
e) extraction of the natural raw material of plant origin with a supercritical solvent, and
f) extraction of the natural raw material of plant origin with a non polar solvent with a dielectric constant, measured as the ratio of the electrical capacity of a capacitor filled with the solvent to the electrical capacity of the evacuated capacitor at room temperature, of less than or equal to 15;

(ii) providing a selectively permeable nanofiltration membrane having a first surface and a second surface opposite to said first surface and having a molecular weight cut-off ranging from about 150 g/mol to about 1,500 g/mol;
(iii) contacting the nanofiltration feed with the first surface of the selectively permeable nanofiltration membrane to separate components in the nanofiltration feed by allowing one or more components of the nanofiltration feed to transfer from the first surface to the second surface across the membrane,
wherein the essential oil or solution comprising an essential oil and at least one organic solvent in contact with the first surface after transfer of the one or more components of the nanofiltration feed forms a retentate and the one or more components of the essential oil or the solution comprising an essential oil and at least one organic solvent contacting the second surface forms a permeate,
wherein pressure at the first surface is greater than pressure at the second surface,
and wherein a concentration of the one or more components of the essential oil or of the solution comprising an essential oil and at least one organic solvent is reduced in the retentate compared to the nanofiltration feed.

2. The process of claim 1 , further comprising recovering any solvent content from the permeate and the retentate.

3. The process of claim 2 , further comprising recovering any solvent content from the permeate and the retentate.

4. The process of claim 1 , further comprising contacting the retentate and/or the permeate with at least one additional nanofiltration membrane.

5. The process of claim 1 , wherein the essential oil derives from plants and is selected from oils produced from berries, seeds, bark, wood, rhiozome, leaves, resin, flowers, peel and root,
essential oil from the genus Citrus,
oils deriving from sweet orange, orange, lemon, lime, grapefruit, bergamot, key lime, pomelo, citron, mandarin, tangerine, bitter orange, rangpur, Persian lime, Clementine, yuzu, kaffir lime, or ugli,
and
allspice oil, juniper oil, cumin oil, cinnamon bark oil, camphor oil, rosewood oil, ginger oil, basil oil, eucalyptus oil, lemongrass oil, peppermint oil, rosemary oil, spearmint oil, tea tree oil, frankincense oil, chamomile oil, clove oil, jasmine oil, lavender oil, rose oil, ylang ylang oil, bergamot oil, grapefruit oil, lemon oil, lime oil, orange oil, and valerian oil.

6. The process of claim 5 , wherein contacting the nanofiltration feed and contacting the retentate and/or the permeate are carried out with two different nanofiltration membranes, one nanofiltration membrane having a molecular weight cut-off between 400 g/mol and 1,500 g/mol and the other nanofiltration membrane having a different molecular weight cut-off between 150 g/mol and 600 g/mol.

7. The process of claim 1 , wherein the retentate has a reduction in at least one chosen from
wax content,
colour, and
a natural and/or synthetic impurity chosen from environmental pollutants, agrochemical residues, extractables from packaging, waxes, plant sterols, lipophilic hormones, colored components, oxidation products, components that create unwanted smell and/or taste in the oil mixture, and vitamins, as compared to the nanofiltration feed.

8. The process of claim 7 , wherein the natural and/or synthetic impurity is an agrochemical residue.

9. The process of claim 1 , wherein the retentate comprises an increased concentration of at least one component chosen from vitamins, plant sterols, lipophilic hormones, colored components, furanocoumarins, and sesquiterpines, relative to the nanofiltration feed.

10. The process of claim 1 , wherein the organic solvent is chosen from
aromatic hydrocarbons, aliphatic hydrocarbons, ketones, glycols, chlorinated solvents, esters, ethers, amines, nitriles, aldehydes, phenols, amides, carboxylic acids, alcohols, furans, lactones, dipolar aprotic solvents, toluene, xylene, benzene, styrene, anisole, chlorobenzene, dichlorobenzene, chloroform, dichloromethane, dichloroethane, methyl acetate, ethyl acetate, isopropyl acetate, butyl acetate, methyl ether ketone (MEK), methyl isobutyl ketone (MIRK), acetone, ethylene glycols, ethanol, methanol, isopropanol, propanol, butanol, hexane, heptane, cyclohexane, dimethoxyethane, methyl tert butyl ether (MTBE), diethyl ether, adiponitrile, N,N-dimethylformamide, dimethylsulfoxide, N,N-dimethylacetamide, dioxane, nitromethane, nitrobenzene, pyridine, carbon disulfide, tetrahydrofuran, methyl-tetrahydrofuran, N-methyl pyrrolidone, N-ethyl pyrrolidone, acetonitrile, and mixtures thereof.

11. The process of claim 1 , wherein the selectively permeable nanofiltration membrane comprises a material chosen from polyethylene, polypropylene, polytetrafluoroethylene (PTFE), polyvinylidene difluoride (PVDF), polysulfone, polyethersulfone, polyacrylonitrile, polyamide, polyimide, polyamideimide, polyetherimide, cellulose acetate, polyaniline, polypyrrole, polyetheretherketone (PEEK), polybenzimidazole, and mixtures thereof.

12. The process of claim 11 , wherein the selectively permeable nanofiltration membrane comprises a polyimide.

13. The process of claim 1 , wherein the selectively permeable nanofiltration membrane is a composite material comprising a support and a selectively permeable layer, wherein the selectively permeable layer comprises a material chosen from-polydimethylsiloxane (PDMS) based elastomers, ethylene-propylene diene (EPDM) based elastomers, polynorborene based elastomers, polyoctenamer based elastomers, polyurethane based elastomers, butadiene and nitrile butadiene rubber based elastomers, natural rubber, butyl rubber based elastomers, polychloroprene (Neoprene) based elastomers, epichlorohydrin elastomers, polyacrylate elastomers, polyethylene, polypropylene, polytetrafluoroethylene (PTFE), polyvinylidene difluoride (PVDF) based elastomers, polyetherblock amides (PEBAX), polyurethane elastomers, crosslinked polyether, polyamide, polyaniline, polypyrrole, and mixtures thereof.

14. The process of claim 1 , wherein the selectively permeable nanofiltration membrane comprises an inorganic material chosen from silicon carbide, silicon oxide, zirconium oxide, titanium oxide, and zeolites.

15. The process of claim 1 , wherein the selectively permeable nanofiltration membrane comprises a polymer membrane with dispersed organic or inorganic matrices in the form of powdered solids present in amounts up to about 20 wt % of the p

Assignees

• Evonik Operations Gmbh

Inventors

• Boam Andrew
• Meniconi Andrea
• Wu Xiaoping

Classifications

• B01D71/701

  Polydimethylsiloxane · CPC title

• B01D69/141

  Heterogeneous membranes, e.g. containing dispersed material; Mixed matrix membranes · CPC title

• Y02W30/74

  Recovery of fats, fatty oils, fatty acids or other fatty substances, e.g. lanolin or waxes · CPC title

• B01D61/027

  Nanofiltration · CPC title

• C11B9/025 Primary

  Recovery by solvent extraction · CPC title