WO2016189330A1 - Procédé d'élimination de contaminants métalliques d'huile de glycéride et procédé de raffinage d'huile de glycéride le comprenant - Google Patents

Procédé d'élimination de contaminants métalliques d'huile de glycéride et procédé de raffinage d'huile de glycéride le comprenant Download PDF

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WO2016189330A1
WO2016189330A1 PCT/GB2016/051562 GB2016051562W WO2016189330A1 WO 2016189330 A1 WO2016189330 A1 WO 2016189330A1 GB 2016051562 W GB2016051562 W GB 2016051562W WO 2016189330 A1 WO2016189330 A1 WO 2016189330A1
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Prior art keywords
oil
ionic liquid
glyceride oil
glyceride
process according
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PCT/GB2016/051562
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English (en)
Inventor
Peter Goodrich
Eoghain O'HARA
Martin Philip Atkins
Christopher Klatt HAMER
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The Queen's University Of Belfast
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Priority to JP2017561966A priority Critical patent/JP2018517037A/ja
Priority to CN201680044213.1A priority patent/CN107922881A/zh
Priority to BR112017025448A priority patent/BR112017025448A2/pt
Publication of WO2016189330A1 publication Critical patent/WO2016189330A1/fr
Priority to PH12017502156A priority patent/PH12017502156A1/en

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    • C—CHEMISTRY; METALLURGY
    • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
    • C11B—PRODUCING, e.g. BY PRESSING RAW MATERIALS OR BY EXTRACTION FROM WASTE MATERIALS, REFINING OR PRESERVING FATS, FATTY SUBSTANCES, e.g. LANOLIN, FATTY OILS OR WAXES; ESSENTIAL OILS; PERFUMES
    • C11B3/00—Refining fats or fatty oils
    • C11B3/02—Refining fats or fatty oils by chemical reaction
    • C11B3/06—Refining fats or fatty oils by chemical reaction with bases
    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23D—EDIBLE OILS OR FATS, e.g. MARGARINES, SHORTENINGS, COOKING OILS
    • A23D9/00—Other edible oils or fats, e.g. shortenings, cooking oils
    • A23D9/02—Other edible oils or fats, e.g. shortenings, cooking oils characterised by the production or working-up
    • C—CHEMISTRY; METALLURGY
    • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
    • C11B—PRODUCING, e.g. BY PRESSING RAW MATERIALS OR BY EXTRACTION FROM WASTE MATERIALS, REFINING OR PRESERVING FATS, FATTY SUBSTANCES, e.g. LANOLIN, FATTY OILS OR WAXES; ESSENTIAL OILS; PERFUMES
    • C11B3/00—Refining fats or fatty oils
    • C11B3/02—Refining fats or fatty oils by chemical reaction
    • C—CHEMISTRY; METALLURGY
    • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
    • C11B—PRODUCING, e.g. BY PRESSING RAW MATERIALS OR BY EXTRACTION FROM WASTE MATERIALS, REFINING OR PRESERVING FATS, FATTY SUBSTANCES, e.g. LANOLIN, FATTY OILS OR WAXES; ESSENTIAL OILS; PERFUMES
    • C11B3/00—Refining fats or fatty oils
    • C11B3/10—Refining fats or fatty oils by adsorption
    • C—CHEMISTRY; METALLURGY
    • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
    • C11C—FATTY ACIDS FROM FATS, OILS OR WAXES; CANDLES; FATS, OILS OR FATTY ACIDS BY CHEMICAL MODIFICATION OF FATS, OILS, OR FATTY ACIDS OBTAINED THEREFROM
    • C11C3/00—Fats, oils, or fatty acids by chemical modification of fats, oils, or fatty acids obtained therefrom

Definitions

  • the present invention is directed to a process for removing metal contaminants from glyceride oil and a refining process incorporating the same.
  • the present invention is directed to a process wherein certain basic ionic liquids are used for treating glyceride oil.
  • the present invention also relates to uses of the basic ionic liquid and to glyceride oil compositions obtained from the ionic liquid treatment.
  • Crude glyceride oils extracted from natural sources typically undergo a variety of refining processes in order to improve the organoleptic properties of the oil or other quality parameters depending on the intended use.
  • oil refining processes extract lipids, pigments, volatile odiferous compounds and other components which either negatively impact upon the oil's stability or present potential toxicity issues.
  • Glyceride oils are known to find use in biodiesel production as well as for human consumption and healthcare products. One issue affecting these applications is the metal content of crude glyceride oil.
  • a principal metal contaminant of crude glyceride oil is iron, which is thought to derive from the machinery and tanks used during processing and storage. Iron, zinc and copper are known to be pro-oxidant metals which can catalyse the oxidation process and contribute to oxidative deterioration of glyceride oil. It is also known for crude glyceride oil to have appreciable quantities of sodium, potassium, calcium, magnesium, chromium, nickel and aluminium metals. Potassium, calcium and magnesium are known to be the most abundant metal constituents in plant material and therefore these metals may be carried forward endogenously to vegetable oils extracted from them.
  • glyceride oil can also be used for the production of biodiesel using a transesterification process whereby triglyceride components of the oil are converted into Fatty Acid Methyl Esters (FAME) by contact with an alcohol in the presence of a catalyst.
  • FAME Fatty Acid Methyl Esters
  • Metal contaminants in the oil can have a detrimental effect on the performance of the transesterification catalyst and it is preferable that the oil have a low metal content in order to mitigate catalyst deactivation in the biodiesel production process. Consequently, there is a need for removing metal contaminants of glyceride oil for both food and biodiesel applications.
  • Glyceride oil refining typically includes a degumming step involving a water wash and/or treatment with aqueous acid (phosphoric acid and/or citric acid). Water washing removes hydratable phosphatides and the acid treatment is used to remove non-hydratable phospholipid components. The degumming step removes sources of phosphorus as a result of removing phospholipid components. Degumming is also known to simultaneously remove metal ions from the oil which form salts of phosphatidic acid in the non-hydratable phosphatides. Refining also typically includes bleaching (e.g. with bleaching earth) which is used not only to improve colour but to also remove contaminants, including trace metals. Degumming and bleaching may not however be completely sufficient for removing metal contaminants, particularly iron, to an adequate extent, especially for biodiesel applications.
  • bleaching e.g. with bleaching earth
  • US 4,629,588 discloses a method for refining glyceride oils using amorphous silica for the removal of phospholipids and associated metal ions from glyceride oils. This method relies on the presence of phospholipids in order for the metal ions to be removed and effectively corresponds to a degumming process.
  • US 3,634,475 discloses a method for removing metals from vegetable oils which comprises washing, in a countercurrent multistage manner, vegetable oil with water which has been pretreated to remove cations therefrom by contacting with a cation exchange resin.
  • WO 2003/075671 discloses a method for removing contaminants including polar materials, free fatty acids, metals, colour bodies, and soaps by treating the oil with a composition containing effective amounts of silica, acidic alumina, clay and optionally citric acid.
  • US 8,764,967 discloses a method for regenerating used cooking oil using an electrochemical device comprising a proton exchange membrane disposed between an anode and cathode, wherein hydrogen gas produced as a result of water hydrolysis reacts with metal ions present in the oil to facilitate their removal.
  • US 6,407,271 describes a process for removing phospholipids and/or polyvalent metals from vegetable oil by emulsifying the oil with an aqueous solution of a salt of a polycarboxylic acid, preferably tetrasodium EDTA, to form a fine suspension of micelles, followed by centrifuging or ultrafiltration.
  • the EDTA salt is said to chelate metallic polyvalent cations (e.g. Fe(ll), Fe(lll), Ca(ll) and Mg (II)) to form complexes which are more stable than the salts of the metal cations and phosphatidic acid or phosphoric or citric acids used in degumming.
  • W01994/021765 describes a process for simultaneously neutralising FFA in glyceride oils and removing contaminants including trace metals.
  • the oil is contacted with a solid alkali metal silicate, such as sodium metasilicate pentahydrate and hydrous sodium polysilicate, before heating and filtering.
  • WO 2012/004810 discloses a process for removing metals in oils and fats by treating with clay followed by an ion exchange resin. This process relies on both adsorbant and resin materials which increases both materials and equipment costs associated with the refining process, particularly if regeneration steps are integrated into the process in order to recycle clay and/or ion exchange resin.
  • Liquid-liquid extraction techniques with polar solvents have previously been disclosed as oil treatments, for instance for the removal of FFA, operating on the basis of the solubility differences of the contaminant and the oil effecting separation by selective partitioning into a particular solvent phase.
  • Meirelles et al. Recent Patents on Engineering 2007, 1 , 95-102, gives an overview of such approaches to the deacidification of vegetable oils.
  • Liquid-liquid extraction methods are generally considered to be advantageous on the basis that they may be performed at room temperature, they do not generate waste products and they benefit from low neutral oil losses.
  • Meirelles et al. observe that there are significant capital costs associated with the implementation of a liquid-liquid extraction process and there remain doubts as to the overall benefits.
  • the polar solvents used in these liquid-liquid extraction techniques are also capable of removing mono- and di- glycerides from the oil in addition to FFA, which may not be desirable.
  • the present invention is based on the use of specifically selected basic ionic liquids comprising a basic anion for extracting metals from glyceride oil, which treatment can be readily integrated into the overall glyceride oil refining process.
  • Treatment of glyceride oil with the basic ionic liquid has been found to at least partially remove pigments and odiferous compounds which are typically removed in a separate bleaching step and a high temperature (for example, 240 °C to 270 °C) deodorization step respectively during conventional refining processes.
  • Treatment with the basic ionic liquid has also been found to at least partially degum glyceride oil.
  • treatment of glyceride oil with the basic ionic liquid means that lower temperatures and/or time periods can be used for the deodorization step as part of the overall refining process and less extensive degumming and/or bleaching may be required, if at all. This has the advantage of reducing energy requirements and materials costs associated with the refining process.
  • the present invention provides a process for removing metal from a metal-containing glyceride oil comprising the steps of: (i) contacting metal-containing glyceride oil comprising a total metal concentration of 10 ppm to 10,000 ppm with a basic ionic liquid to form a treated glyceride oil; wherein the basic ionic liquid comprises a basic anion selected from hydroxide, alkoxide, alkylcarbonate, hydrogen carbonate, carbonate, serinate, prolinate, histidinate, threoninate, valinate, asparaginate, taurinate and lysinate; and a organic quaternary ammonium cation; and
  • step (i) separating the treated glyceride oil from an ionic compound comprising the organic quaternary ammonium cation after contacting the glyceride oil with the basic ionic liquid; wherein the treated glyceride oil has a reduced metal concentration compared to the glyceride oil contacted in step (i);
  • the glyceride oil which is contacted does not comprise palm oil.
  • the total concentration of metal in the glyceride oil prior to contact in step (i) is 50 ppm to 5,000 ppm, for example 100 ppm to 2,000 ppm.
  • the basic ionic liquid treatment according to the process of the present invention may be suitably applied to crude metal-containing glyceride oil which has not undergone any previous refining steps.
  • the above process may be applied to metal-containing glyceride oil which has undergone one or more additional refining steps prior to treatment with the basic ionic liquid.
  • the treatment with basic ionic liquid can therefore be integrated into a glyceride oil refining process at several stages.
  • the treatment can be implemented at a stage which precedes exposure to high temperatures so as to reduce the amount of metal contaminants, particularly iron, that would otherwise lead to darkening of the glyceride oil, negatively impact upon organoleptic properties.
  • the treatment can be implemented towards the end of the refining process as a means for reducing the level of metal contaminants after contact with metal vessels or machinery associated with processing where metal leaching into the oil, particularly at high temperature, may be more likely. This flexibility makes the treatment with basic ionic liquid in accordance with the present invention particularly attractive for integrating into pre-existing refining processes and systems.
  • the present invention also provides a process for refining metal-containing glyceride oil, said process comprising the steps of: contacting metal-containing glyceride oil with a basic ionic liquid to form a treated glyceride oil; wherein the basic ionic liquid comprises a basic anion selected from hydroxide, alkoxide, alkylcarbonate, hydrogen carbonate, carbonate, serinate, prolinate, histidinate, threoninate, valinate, asparaginate, taurinate and lysinate; and a organic quaternary ammonium cation;
  • step (i) separating the treated glyceride oil from an ionic compound comprising the organic quaternary ammonium cation after contacting the glyceride oil with the basic ionic liquid, wherein the treated glyceride oil has a reduced metal concentration compared to the glyceride oil contacted in step (i);
  • the glyceride oil which is contacted does not comprise palm oil.
  • the total concentration of metal in the glyceride oil prior to contact in step (i) is 10 ppm to 10,000 ppm, preferably 50 ppm to 5,000 ppm, most preferably 100 ppm to 2,000 ppm.
  • glycolide oil refers to an oil or fat which comprises triglycerides as the major component thereof.
  • the triglyceride component may be at least 50 wt.% of the glyceride oil.
  • the glyceride oil may also include mono- and/or di-glycerides.
  • the glyceride oil is at least partially obtained from a natural source (for example, a plant, animal or fish/crustacean source) and is also preferably edible.
  • Glyceride oils include vegetable oils, marine oils and animal oils/fats which typically also include phospholipid components in their crude form. Vegetable oils include all plant, nut and seed oils.
  • suitable vegetable oils which may be of use in the present invention include: agai oil, almond oil, beech oil, cashew oil, coconut oil, colza oil, corn oil, cottonseed oil, grapefruit seed oil, grape seed oil, hazelnut oil, hemp oil, lemon oil, macadamia oil, mustard oil, olive oil, orange oil, peanut oil, pecan oil, pine nut oil, pistachio oil, poppyseed oil, rapeseed oil, rice bran oil, safflower oil, sesame oil, soybean oil, sunflower oil, walnut oil and wheat germ oil.
  • vegetable oils are those selected from coconut oil, corn oil, cottonseed oil, groundnut oil, olive oil, rapeseed oil, rice bran oil, safflower oil, soybean oil and sunflower oil.
  • Suitable marine oils include oils derived from the tissues of oily fish or crustaceans (e.g. krill).
  • suitable animal oils/fats include pig fat (lard), duck fat, goose fat, tallow oil, and butter.
  • FFA which may be present in the glyceride oils include monounsaturated, polyunsaturated and saturated FFA.
  • unsaturated FFA include: myristoleic acid, palmitoleic acid, sapienic acid, oleic acid, elaidic acid, vaccenic acid, linoleic acid, linoelaidic acid, a-linolenic acid, arachidonic acid, eicosapentaenoic acid, erucic acid and docosahexaenoic acid.
  • saturated FFA examples include: caprylic acid, capric acid, undecylic acid, lauric acid, tridecylic acid, myristic acid, palmitic acid, margaric acid, stearic acid, nonadecylic acid, arachidic acid, heneicosylic acid, behenic acid, lignoceric acid and cerotic acid.
  • the glyceride oil used in the present invention is a vegetable oil. More preferably, the glyceride oil is a vegetable oil selected from coconut oil, corn oil, cottonseed oil, groundnut oil, olive oil, rapeseed oil, rice bran oil, safflower oil, soybean oil and sunflower oil.
  • rapeseed oil used herein includes oil extracted from the seeds of the soybean (Glycine max).
  • rapeseed oil used herein is synonymous with canola oil and refers to the oil derived from a species of rape plant, for example rapeseed (Brassica napus L.) or field mustard/turnip rape (Brassica rapa subsp. oleifera, syn. B. campestris L).
  • the process for refining glyceride oil in accordance with the present invention does not extend to glyceride oils which comprise palm oil.
  • palm oil used herein includes an oil at least partially derived from a tree of genus Elaeis, forming part of the Arecaceae genera, and including the species Elaeis guineensis (African oil palm) and Elaeis oleifera (American oil palm), or hybrids thereof. Reference to palm oil herein therefore also includes palm kernel oil, as well as fractionated palm oil, for example palm oil stearin or palm oil olein fractions.
  • crude glyceride oil is intended to mean glyceride oil which has not undergone refining steps following oil extraction.
  • crude glyceride oil will not have undergone degumming, deacidification, winterisation, bleaching, depigmentation or deodorization.
  • refined used herein in reference to glyceride oil is intended to mean a glyceride oil which has undergone one or more refining steps, such as degumming, deacidification, winterisation, bleaching, depigmentation and/or deodorization.
  • metal used herein in reference to the metal-containing glyceride oil is intended to refer to metal-containing compounds or complexes, as well as free metal ions.
  • Metal-containing compounds include metal salts, metal oxides or metal sulphides and the like, whilst metal complexes include, for example, coordination complexes.
  • metals that may be removed as part of the basic ionic liquid treatment of the present invention include alkali metals (such as lithium, sodium and potassium) alkaline earth metals (such as beryllium, magnesium, calcium, strontium and barium) transition metals (such as chromium, manganese, iron, cobalt, nickel, copper, zinc, cadmium and mercury) and post-transition metals (such as aluminium, tin and lead).
  • alkali metals such as lithium, sodium and potassium
  • alkaline earth metals such as beryllium, magnesium, calcium, strontium and barium
  • transition metals such as chromium, manganese, iron, cobalt, nickel, copper, zinc, cadmium and mercury
  • post-transition metals such as aluminium, tin and lead.
  • a preferred class of metals for removal from the glyceride oil is transition metals.
  • preferred metals for removal by the basic ionic liquid treatment in accordance with the present invention include sodium, potassium, calcium, magnesium, strontium, barium, iron, zinc, nickel, copper, chromium and aluminium.
  • Particularly preferred metals for removal from the oil include, strontium, barium, iron, copper, nickel and chromium.
  • Most preferred metals for removal from the oil are iron and copper.
  • ionic liquid refers to a liquid that is capable of being produced by melting a salt, and when so produced consists solely of ions.
  • An ionic liquid may be formed from a homogeneous substance comprising one species of cation and one species of anion, or it can be composed of more than one species of cation and/or more than one species of anion.
  • an ionic liquid may be composed of more than one species of cation and one species of anion.
  • An ionic liquid may further be composed of one species of cation, and one or more species of anion.
  • an ionic liquid may be composed of more than one species of cation and more than one species of anion.
  • ionic liquid includes compounds having both high melting points and compounds having low melting points, e.g. at or below room temperature.
  • many ionic liquids have melting points below 200 °C, preferably below 150 °C, particularly below 100 °C, around room temperature (15 to 30 °C), or even below 0 °C.
  • Ionic liquids having melting points below around 30 °C are commonly referred to as "room temperature ionic liquids".
  • room temperature ionic liquids the structures of the cation and anion prevent the formation of an ordered crystalline structure and therefore the salt is liquid at room temperature.
  • ionic liquid as used herein also includes "non-classical" ionic liquids which exhibit ionic liquid properties but exist stably only in the presence of a solvent or on a support.
  • basic ionic liquids used in accordance with the present invention also include quaternary ammonium hydroxide ionic liquids. These ionic liquids are typically considered to be “non-classical” ionic liquids because Hofmann elimination can make them unstable in neat form. Nevertheless, such ionic liquids are known to exist stably when immobilized on a support (see, for instance, Chem. Commun., 2004, 1096-1097) or in the presence of a solvent, for example an aqueous co-solvent.
  • Basic ionic liquids used in accordance with the present invention also include quaternary ammonium bicarbonate ionic liquids. These ionic liquids are also typically considered to be "non-classical" ionic liquids because they may also suffer from Hofmann elimination (although to far less an extent than hydroxide based ionic liquids) as well as thermal decomposition of the bicarbonate anion to the carbonate form. Nevertheless, such ionic liquids are known to exist stably in the presence of a solvent, for example an aqueous solvent.
  • a liquid may be used which includes the basic ionic liquid together with a solvent, such as an aqueous solvent. Additional co-solvents, such as an alcohol co- solvent, may also be present.
  • a solvent such as an aqueous solvent.
  • co-solvents such as an alcohol co- solvent
  • Ionic liquids are most widely known as solvents, because of their negligible vapour pressure, temperature stability, low flammability and recyclability, which also make them environmentally friendly. Due to the vast number of anion/cation combinations that are available it is possible to fine-tune the physical properties of the ionic liquid (e.g. melting point, density, viscosity, and miscibility with water or organic solvents) to suit the requirements of a particular application.
  • an "ionic compound comprising the organic quaternary ammonium cation" in step (ii) it is intended to refer to an ionic compound which derives from the basic ionic liquid contacted in step (i), at least by virtue of the organic quaternary ammonium cation present in the ionic compound separated in step (ii).
  • the glyceride oil contains FFA and the ionic compound comprising the organic quaternary ammonium cation also comprises an anion of a fatty acid.
  • the ionic compound which is separated from the treated glyceride oil may also be an ionic liquid as defined herein, which is different to the basic ionic liquid which is used for contacting the glyceride oil initially.
  • the ionic compound comprising the organic quaternary ammonium cation comprises the same anion as the ionic liquid used for contacting the glyceride oil initially, in other words the ionic compound separated from the treated glyceride oil is the same as the ionic liquid used for contacting the glyceride oil initially.
  • the ionic liquids used in the process of the present invention are based on organic quaternary ammonium cations.
  • Organic quaternary ammonium cation used herein is intended to refer to a positively charged ammonium cation wherein the nitrogen atom is bonded only to substituted or unsubstituted Ci to C 12 hydrocarbyl groups.
  • hydrocarbyl group refers to a univalent or multi-valent radical derived from a hydrocarbon and may include alkyl, cycloalkyi, alkenyl, alkynyl, or aryl groups.
  • the organic quaternary ammonium cation of the basic ionic liquid is selected from: [N(R a )(R b )(R c )(R d )] + , wherein: R a , R b , R c and R d are each independently selected from a Ci to Cs, straight chain or branched alkyl group or a C 3 to C 6 cycloalkyi group; or any two of R a , R b , R c and R d combine to form an alkylene chain -(CH 2 ) q - wherein q is from 3 to 6; and wherein said alkyl or cycloalkyi groups may optionally be substituted by one to three groups selected from: Ci to C 4 alkoxy, C 2 to Cs alkoxyalkoxy, C3 to C & cycloalkyi, -OH, -SH, -00 2 (0 !
  • the organic quaternary ammonium cation of the basic ionic liquid is selected from:
  • R a , R b , R c and R d are each independently selected from a Ci to Cs, straight chain or branched alkyl group; and wherein said alkyl group may optionally be substituted by one to three groups selected from: Ci to C 4 alkoxy, C2 to Cs alkoxyalkoxy, C 3 to C 6 cycloalkyl, -OH, -SH , -C0 2 (Ci to C 6 )alkyl, and -OC(0)(Ci to C6)alkyl, for example by one to three -OH groups.
  • organic quaternary ammonium cation is selected from:
  • R a , R b , R c and R d are each independently selected from a Ci to C 4 , straight chain or branched alkyl group, including C-i , C2 and C 4 alkyl, wherein at least one of R a , R b , R c or R d is substituted by a single -OH group.
  • organic quaternary ammonium cation is choline:
  • the basic ionic liquids used for the present invention incorporate basic anions selected from hydroxide, alkoxide, alkylcarbonate, hydrogen carbonate, carbonate, serinate, prolinate, histidinate, threoninate, valinate, asparaginate, taurinate and lysinate. These anions are not merely spectator anions selected by virtue of their ability to confer a certain melting point on the resulting ionic liquid.
  • the basicity of the anions forming part of the ionic liquids used in conjunction with the present invention is believed to contribute to their ability to remove chloropropanol and glycidol, or their fatty acid esters, from glyceride oil.
  • the term "basic” used herein refers to Br0nsted bases having the ability to react with (neutralise) acids to form salts.
  • the pH range of bases is from above 7.0 to 14.0 when dissolved or suspended in water.
  • the basic anion is selected from alkylcarbonate, hydrogen carbonate, carbonate, hydroxide and alkoxide; preferably hydrogen carbonate, alkylcarbonate and carbonate; and more preferably hydrogen carbonate.
  • the alkyl group may be linear or branched and may be substituted or unsubstituted. In one preferred embodiment, the alkyl group is unsubstituted. In another preferred embodiment, the alkyl group is unbranched. In a more preferred embodiment, the alkyl group is unsubstituted and unbranched.
  • the alkyl group may comprise from 1 to 10 carbon atoms, preferably from 1 to 8 carbon atoms and more preferably form 1 to 4 carbon atoms.
  • the alkyl group may thus be selected from methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl and/or decyl.
  • branched alkyl groups such as iso-propyl, iso- butyl, sec-butyl and/or tert-butyl may also be used.
  • Especially preferred are methyl, ethyl, propyl and butyl.
  • the alkyl group is selected from methyl and ethyl.
  • the basic anion is selected from serinate, prolinate, histidinate, threoninate, valinate, asparaginate, taurinate and lysinate.
  • the basic anion is selected from serinate, lysinate, prolinate, taurinate and threoninate, more preferably from lysinate, prolinate and serinate, most preferably the basic anion is lysinate.
  • the basic ionic liquid used for contacting the glyceride oil in step (i), as well as the ionic compound comprising the organic quaternary ammonium cation separated in step (ii), should have little or no toxicity and/or be readily and substantially separable from the treated oil.
  • a basic ionic liquid comprising a choline cation is particularly suitable for use with the process of the present invention.
  • Choline is a water soluble essential nutrient grouped with the B- complex vitamins which is a precursor to acetylcholine, involved in numerous physiological functions. Choline has particularly low toxicity and excellent biodegradability, making it a natural ingredient that is capable of forming an ionic liquid which is particularly useful in the process of the present invention.
  • the basi liquid is selected from choline bicarbonate:
  • alkyl group is an alkyl group as described hereinbefore; or choline hydroxide:
  • Basic ionic liquids comprising a basic anion selected from serinate, prolinate, histidinate, threoninate, valinate, asparaginate, taurinate and lysinate are also particularly suitable in the process of the present invention due to the particularly low toxicity of these amino acid derivatives.
  • the basic ionic liquid is choline bicarbonate:
  • the basic ionic liquid used in contacting step (i), as well as the ionic compound comprising the organic quaternary ammonium cation separated in step (ii), preferably have low oil solubility and preferentially partition into a non-oil phase, such as an aqueous phase, facilitating their removal from the treated oil. More preferably, the basic ionic liquid is immiscible with the oil. By immiscible with the oil it is meant that the ionic liquid is soluble in the glyceride oil at a concentration of less than 50 ppm, preferably less than 30 ppm, more preferably less than 20 ppm, most preferably, less than 10 ppm, for example, less than 5 ppm. Thus, the solubility of the basic ionic liquid may be tailored so that the basic ionic liquid is immiscible with the oil.
  • the contacting step (i) of the process of the present invention is carried out at a temperature of less than 80 °C, preferably from 25 to 65 °C, more preferably from 35 to 55 °C, for example, 40 °C.
  • a temperature of less than 80 °C preferably from 25 to 65 °C, more preferably from 35 to 55 °C, for example, 40 °C.
  • the contacting step (i) is carried out at a pressure of from 0.1 MPa absolute to 10 MPa absolute (1 bar absolute to 100 bar absolute).
  • the contacting step may be carried out by contacting glyceride oil with the basic ionic liquid in a vessel wherein the resulting mixture is stirred using, for example, a mechanical stirrer, an ultrasonic stirrer, an electromagnetic stirrer or by bubbling an inert gas through the mixture.
  • the basic ionic liquid and the glyceride oil may be contacted in a volume ratio of from greater than 1 :40 to 1 :300, and may be contacted in a mass ratio of from 1 :50, preferably from 1 : 100.
  • the contacting step may last from 1 minute to 60 minutes, preferably 2 to 30 minutes, more preferably, 5 to 20 minutes and most preferably, 8 to 15 minutes.
  • the basic ionic liquid is contacted with the glyceride oil.
  • the basic ionic liquid may added in neat form or as part of a liquid additionally comprising a solvent or mixture of solvents which is/are compatible with the basic ionic liquid and the glyceride oil.
  • a solvent or mixture of solvents may be used to modify the viscosity of the basic ionic liquid as desired.
  • use of a solvent may confer desirable properties on the liquid structure of the liquid based reaction that are particularly suitable for promoting the reaction of the basic ionic liquid.
  • Suitable solvents for this purpose include polar solvents, such as water, or alcohol, for example methanol or ethanol.
  • the glyceride oil is contacted with a liquid comprising the basic ionic liquid and a solvent, wherein the concentration of basic ionic liquid in the liquid is from 15 wt.% to 90 wt.%.
  • the solvent is an aqueous solvent, such as deionised water.
  • the glyceride oil is contacted with a liquid comprising the basic ionic liquid and a solvent, such as an aqueous solvent, and the concentration of basic ionic liquid in the liquid is 50 wt.% to 90 wt.%, for example from 75 wt.% to 85 wt.%.
  • the glyceride oil is contacted with a liquid comprising the basic ionic liquid and a solvent, such as an aqueous solvent, wherein the concentration of basic ionic liquid in the liquid is 15 wt.% to 60 wt.%, preferably from 40 wt.% to 50 wt.%.
  • a solvent such as an aqueous solvent
  • additional co-solvents may also be present.
  • alcohol co-solvent(s) may also be present, for example, at between 1 wt.% and 20 wt.% of the liquid comprising the basic ionic liquid and aqueous solvent.
  • additional co-solvents may also be present.
  • alcohol co-solvent(s) may also be present, for example, at between 1 wt.% and 20 wt.% of the liquid comprising the basic ionic liquid and aqueous solvent.
  • Separation of the ionic compound comprising the organic quaternary ammonium cation in step (ii) of the process may be carried out by gravity separation (for example, in a settling unit), where the treated glyceride oil is generally the upper phase and the ionic compound comprising the organic quaternary ammonium cation together with any solvent are incorporated in the lower phase in the settling unit.
  • Separation of the ionic compound comprising the organic quaternary ammonium cation may also be achieved using, for example, a decanter, a hydrocyclone, electrostatic coalesce, a centrifuge or a membrane filter press.
  • the phases are separated using a centrifuge. Contacting and separation steps may be repeated several times, for example 2 to 4 times.
  • the ionic compound comprising the organic quaternary ammonium cation separated in step (ii) is a solid which is precipitated after contacting step (i), for instance, following formation of a quaternary ammonium-FFA salt
  • the solid ionic compound may be separated from the oil by filtration.
  • a polar solvent as described hereinbefore which is immiscible with the oil phase may be added to solubilise the solid salt, following which the salt-containing phase may be separated from the oil by the methods described above.
  • the glyceride oil (hereinafter “oil feed stream”) is generally introduced at or near the bottom of the counter-current reaction column and the basic ionic liquid (hereinafter “ionic liquid feed stream”) at or near the top of the counter- current reaction column.
  • ionic liquid feed stream the basic ionic liquid
  • a treated oil phase (hereinafter “product oil stream”) is withdrawn from the top of the column and a phase containing an ionic compound comprising the organic quaternary ammonium cation and solvent when present (hereinafter “secondary stream”) from at or near the bottom thereof.
  • the counter-current reaction column has a sump region for collecting the secondary stream.
  • the oil feed stream is introduced to the counter-current reaction column immediately above the sump region.
  • More than one counter-current reaction column may be employed, for example 2 to 6, preferably 2 to 3 columns arranged in series.
  • the counter-current reaction column is packed with a structured packing material, for example, glass Raschig rings, thereby increasing the flow path for the oil and basic ionic liquid through the column.
  • the counter- current reaction column may contain a plurality of trays.
  • contacting and separating steps are carried out together in a centrifugal contact separator, for example, a centrifugal contact separator as described in US 4,959, 158, US 5,571 ,070, US 5,591 ,340, US 5,762,800, WO 99/12650, and WO 00/29120.
  • Suitable centrifugal contact separators include those supplied by Costner Industries Nevada, Inc.
  • Glyceride oil and the liquid comprising the ionic liquid may be introduced into an annular mixing zone of the centrifugal contact separator.
  • the glyceride oil and the basic ionic liquid are introduced as separate feed streams into the annular mixing zone.
  • the glyceride oil and the basic ionic liquid are rapidly mixed in the annular mixing zone.
  • the resulting mixture is then passed to a separation zone wherein a centrifugal force is applied to the mixture to produce a clean separation of an oil phase and a secondary phase.
  • a plurality of centrifugal contact separators are used in series, preferably, 2 to 6, for example 2 to 3.
  • the oil feed stream is introduced into the first centrifugal contact separator in the series while the basic ionic liquid feed stream is introduced into the last centrifugal contact separator in the series such that oil of progressively decreasing content of, for instance, FFA or free metal cations is passed from the first through to the last centrifugal contact separator in the series while a basic ionic liquid stream of progressively increasing content of, for instance, quaternary ammonium-FFA salt and/or metal cation content is passed from the last through to the first centrifugal contact separator in the series.
  • a phase containing an ionic compound comprising the organic quaternary ammonium cation is removed from the first centrifugal contact separator and the treated oil phase is removed from the last centrifugal contact separator in the series.
  • residual basic ionic liquid that is present in the treated glyceride may be recovered by passing the product oil stream through a silica column such that the residual ionic liquid is adsorbed onto the silica column.
  • the adsorbed ionic liquid may then be washed off the silica column using a solvent for the ionic liquid and the ionic liquid may be recovered by driving off the solvent at reduced pressure.
  • the treated glyceride oil may also be passed through a coalescer filter for coalescing fine droplets of non-oil phase liquid, for instance liquid comprising an ionic compound comprising the organic quaternary ammonium cation, so as to produce a continuous phase and facilitate phase separation.
  • a coalescer filter for coalescing fine droplets of non-oil phase liquid, for instance liquid comprising an ionic compound comprising the organic quaternary ammonium cation, so as to produce a continuous phase and facilitate phase separation.
  • the basic ionic liquid used for contact step (i) is used in combination with a solvent
  • the coalescer filter is wetted with the same solvent to improve filtration.
  • the basic ionic liquid may be provided on a support material. Suitable supports for use in the present invention may be selected from silica, alumina, alumina-silica, carbon, activated carbon or a zeolite.
  • the support is silica.
  • the supported form may be provided for contact with
  • contacting and separation steps may also be carried out together by passing the oil through a column packed with the supported ionic liquid (i.e. a packed bed arrangement).
  • a column packed with the supported ionic liquid i.e. a packed bed arrangement
  • a fixed-bed arrangement having a plurality of plates and/or trays may be used.
  • the ionic liquid may be physisorbed or chemisorbed on the support material, and preferably physisorbed.
  • the ionic liquid may be adsorbed onto the support in a basic ionic liquid:support mass ratio of from 10: 1 to 1 :10, preferably in a basic ionic liquid:support mass ratio of from 1 :2 to 2: 1 .
  • treatment of the metal-containing glyceride oil with basic ionic liquid in accordance with the present invention is capable of reducing the metal content of the glyceride oil.
  • reaction mechanisms are believed to be possible as a result of contacting the oil with the ionic liquid, which are discussed in further detail below.
  • the metal content of glyceride oil is believed to derive from metal vessels and machinery used for extraction, processing and storage of the glyceride oils, as well as from metal contaminants present in ecosystems, such as from fertilizers or contaminated soils, which can be absorbed by vegetation or otherwise enter the food chain.
  • the metal of the metal-containing glyceride oil is present in the form of free metal ions and/or as one or more metal-containing compounds or complexes.
  • the metal-containing glyceride oil contacted in step (i) comprises one or more metals selected from alkali metals, alkaline earth metals, transition metals and post-transition metals; preferably transition metals. In some embodiments, the metal-containing glyceride oil contacted in step (i) comprises one or more metals selected from lithium, sodium, potassium, beryllium, magnesium, calcium, chromium, manganese, iron, cobalt, nickel, copper, zinc, cadmium, mercury, aluminium, tin and lead.
  • the metal-containing glyceride oil contacted in step (i) comprises one or more metals selected from sodium, potassium, calcium, magnesium, iron, zinc, nickel, copper, chromium and aluminium.
  • the metal-containing glyceride oil contacted in step (i) comprises one or more metals selected from iron, copper, chromium, and nickel; most preferably wherein the glyceride oil contacted in step (i) comprises iron and/or copper.
  • one possible reaction mechanism by which the basic ionic liquid treatment of the present invention is thought to extract metals is by forming metal-containing complexes.
  • Such complexes may include ionic complexes, complexes resulting from hydrogen bonding, as well as charge-transfer complexes.
  • Another possible means by which metals may be extracted by the basic ionic liquid treatment is by means of cation exchange with free metal cations to form salts which preferentially partition out of the oil phase.
  • the basicity of the basic ionic liquid used in accordance with the present invention may also modify the proton activity of the oil which may lead to precipitation of metal-containing compounds.
  • the basic ionic liquid used in accordance with the present invention has been found to neutralise FFA present in the oil and form quaternary ammonium-FFA salts. It is possible that these salts formed as a result of the acid-base reaction may also complex metals and contribute to their removal from the oil upon separation of the salt from the treated oil in step (ii). Thus, in some embodiments, where the glyceride oil which is contacted in step (i) comprises FFA, the ionic compound comprising the organic quaternary ammonium cation which is separated in step (ii) may comprise an anion of a fatty acid.
  • the organic quaternary ammonium cation of the basic ionic liquid may have one or more of the hydrocarbyl groups substituted by one to three groups selected from: Ci to C 4 alkoxy, C 2 to Cs alkoxyalkoxy, C 3 to C 6 cycloalkyl, -OH, -SH, -C0 2 (Ci to C 6 )alkyl, -OC(0)(Ci to C 6 )alkyl.
  • polar substituents are present, especially -OH which is capable of hydrogen bonding, such groups may enhance the formation of complexes with metal in the oil.
  • the organic quaternary ammonium cation comprises at least one hydrocarbyl group substituted by a single -OH.
  • Analytical methods suitable for determining the concentration of metals in glyceride oil include high-resolution Inductively Coupled Plasma (ICP) Spectrometry analysis, such as ICP-MS (see, for example, J. Agric. Food Chem. 2013 Mar 6; 61 (9):2276- 83) or with optical emission spectrometry (ICP-OES); plasma emission spectroscopy (A. J. Dijkstra and D. Meert, J.A.O.C.S. 59, 199 (1982)); and X-ray fluorescence analysis.
  • ICP-OES analysis is used to determine the metal concentration in connection with the present invention.
  • the treated glyceride oil separated in step (ii) has a metal concentration which is at least 50 wt.%, preferably at least 75 wt.%, lower than the metal-containing glyceride oil contacted in step (i), for example as determined using ICP-OES analysis.
  • At least one further refining step is conducted after treatment of the glyceride oil with the basic ionic liquid.
  • the skilled person is aware of the different refining steps typically used in edible oil processing, including for example refining steps discussed in: “Practical Guide to Vegetable Oil Processing", 2008, Monoj K. Gupta, AOCS Press, as well as in the Edible Oil Processing section of the "AOCS Lipid Library” website (1ipidlibrary.aocs.org).
  • the at least one further refining step (iii) may, for instance, be selected from: degumming, bleaching, winterization, depigmentation and deodorisation.
  • Metal contaminants, particularly iron, can cause darkening of glyceride oil during exposure to heat such as in the case of the deodorisation step and so the basic ionic liquid treatment preferably precedes deodorisation.
  • the at least one further refining step according to the process of the present invention comprises deodorisation.
  • the at least one further refining step (iii) comprises the steps of degumming, bleaching and deodorization.
  • the at least one further refining step (iii) comprises a deodorisation step and the process does not comprise a step of degumming and/or bleaching. Therefore, in exemplary embodiments, the at least one further refining step comprises the steps of degumming and deodorization, but no bleaching. In other exemplary embodiments, the at least one further refining step comprises the steps of bleaching and deodorization, but no degumming step.
  • An additional advantage of the treatment with basic ionic liquid in accordance with the present invention is that the treatment has also been found to at least partially remove pigments and odiferous compounds which are typically removed in a high temperature (for example, 240 °C to 270 °C) deodorization step during conventional refining processes.
  • Treatment of glyceride oil with the basic ionic liquid means that lower temperatures and/or time periods can be used for the deodorization step as part of the overall refining process. This has the advantage of reducing the energy requirements of the refining process.
  • Degumming typically involves contacting the oil with aqueous phosphoric acid and/or aqueous citric acid to remove both hydratable and non-hydratable phosphatides (NHP).
  • citric acid or phosphoric acid is added as a 50 wt% aqueous solution.
  • the aqueous acid is used in an amount of about 0.02 % to about 0.20 % of acid by weight of oil, preferably 0.05 % to about 0.10 % of acid by weight of oil.
  • the degumming step is carried out at a temperature of from about 50 to 1 10 °C, preferably 80 °C to 100 °C, for example 90 °C.
  • the degumming step may suitably last from 5 minutes to 60 minutes, preferably 15 to 45 minutes, more preferably, 20 to 40 minutes, for example 30 minutes.
  • the aqueous phase is separated before the degummed oil is typically dried. Drying of the degummed oil suitably takes place at a temperature of from 80 to 1 10 °C for a suitable time period, for example 20 to 40 min, at reduced pressure, for instance, at 2 to 3 kPa (20 to 30 mbar).
  • glyceride oils with low phosphatide content for example, less than 20 ppm by weight of phosphorus
  • a dry degumming process may be used in which the phosphoric acid or citric acid is added without significant dilution with water (for example, an 85 % acid solution).
  • NHP are converted into phosphatidic acid and a calcium or magnesium bi-phosphate salt which can be removed from the oil in a subsequent bleaching step.
  • dry degumming is known to be less well suited since excessive amounts of bleaching earth are required.
  • Bleaching is incorporated into an edible oil refining process to reduce colour bodies, including chlorophyll, residual soap and gums, trace metals and oxidation products.
  • Bleaching typically involves contacting the oil with an amount of bleaching clay or earth, for example from 0.5 to 5 wt.% clay based on the mass of the oil.
  • Bleaching clays or earths are typically composed of one or more of three types of clay minerals: calcium montmorillonite, attapulgite, and sepiolite. Any suitable bleaching clay or earth may be used in accordance with the present invention, including neutral and acid activated clays (e.g. bentonite).
  • the oil is suitably contacted with bleaching clay for 15 to 45 minutes, preferably 20 to 40 minutes before the earth is separated, typically be filtratio.
  • the oil is typically contacted with bleaching clay or earth at a temperature of from 80 °C to 125 ° C, preferably at a temperature of from 90 ° C to 1 10 ° C.
  • a second stage of the bleaching process is conducted under reduced pressure (“dry bleaching"), for example at 2 to 3 kPa (20 to 30 mbar).
  • Conventional glyceride oil refining processes typically include a FFA neutralisation step with a strong base, for example sodium hydroxide or potassium hydroxide (corresponding to a so called “chemical refining” process).
  • a strong base for example sodium hydroxide or potassium hydroxide
  • deacidification can be achieved by adjusting the deodorisation parameters accordingly to ensure that volatile FFA is removed in that step (a so called “physical refining” process).
  • a disadvantage of a FFA neutralisation step (“chemical refining”) is that it is accompanied by unwanted saponification, lowering triglyeride content, whilst soap formation can lead to substantial neutral oil losses as a result of emulsification.
  • the basic ionic liquid treatment forming part of the refining process of the present invention is effective at neutralising FFA in the oil and may entirely replace a conventional neutralisation step used in a chemical refining process.
  • treatment with the basic ionic liquid has the benefit that it does not lead to saponification of neutral oil.
  • the refining process does not include a neutralisation step with an inorganic base (e.g. sodium hydroxide).
  • FFA present in the oil may be neutralised upon contact with the basic ionic liquid to form a quaternary ammonium-FFA salt.
  • the amount of basic ionic liquid employed in the contacting step is at least stoichiometric with the molar amount of FFA contained in the oil.
  • the molar ratio of the ionic liquid to FFA in the oil may be from 1 : 1 to 10 : 1 , or from 1 .5 : 1 to 5 : 1 .
  • the content of FFA in the glyceride oil may be determined prior to treatment with basic ionic liquid using common titration techniques, of which the person of skill in the art is aware. For instance, titration with sodium hydroxide using phenolphthalein indicator may be used to determine the FFA content of glyceride oil.
  • the basic ionic liquid is selected to provide low melting fatty acid salts with linear d 2 to Ci 8 FFAs.
  • Particularly preferred basic ionic liquids form salts with such FFAs having melting points of less than 100 °C.
  • Such salts may be conveniently separated from the treated glyceride oil using liquid-liquid separation techniques discussed herein.
  • deodorization corresponds to a stripping process in which an amount of stripping agent is passed through an oil in a distillation apparatus, typically by means of direct injection, at reduced pressure for a period of time so as to vaporize and extract volatile components, such as FFA, aldehydes, ketones, alcohols, hydrocarbons, tocopherols, sterols, and phytosterols.
  • the stripping agent is preferably steam, although other agents such as nitrogen may be used.
  • the amount of stripping agent suitably used is from about 0.5 % to about 5 % by weight of oil.
  • the temperature range of deodorization for the refining process according to the present invention is suitably from 160 °C to 270 °C. Where reference is made herein to the temperature of the deodorization step, this refers to the temperature the oil is heated to before being exposed to the stripping agent.
  • the pressure range of deodorization is suitably from 0.1 to 0.4 kPa (1 to 4 mbar), preferably 0.2-0.3 kPa (2 to 3 mbar). Suitable time periods for deodorization are typically from 30 to 180 minutes, for example 60 to 120 minutes, or 60 to 90 minutes.
  • the skilled person is able to determine a suitable length of deodorization by analysing the appearance and composition of the glyceride oil. For instance, determining the p-anisidine value (AnV) of the oil.
  • the p-anisidine value of an oil is a measure of its oxidative state and, more specifically, provides information regarding the level of secondary oxidation products contained in an oil, although primarily aldehydes such as 2-alkenals and 2,4-dienals.
  • the p-anisidine value (AnV) therefore also gives an indication of the level of oxidation products which are intended to be removed by means of the deodorization step. For instance, satisfactory deodorization may be achieved where, for example, the AnV is less than 10, preferably less than 5, as determined by AOCS Official Method Cd 18-90.
  • the amount of aldehyde and ketone components of the oil can be determined, which are typically associated with a crude oil's odour, to determine whether sufficient deodorization has taken place.
  • Typical volatile odiferous aldehyde and ketone components of crude or rancid palm oil include: acetaldehyde, benzaldehyde, n-propanal, n-butanal, n-pentanal, n-hexanal, n-octanal, n-nananal, 2- butenal, 3-methylbutanal, 2-methylbutanal, 2-pentenal, 2-hexenal, 2E,4E-decadienal, 2E,4Z-decadienal, 2-butanone, 2-pentanone, 4-methyl-2-pentanone, 2-heptanone, 2- nonanone.
  • each of these components is individually present in a deodorized oil in an amount less than 3 mg/kg of
  • the amount of aldehydes and ketones may be readily determined by chromatographic methods, for instance GC-TOFMS or GCxGC-TOFMS.
  • derivatization of aldehydes and ketones may be used to improve chromatographic analysis.
  • aldehydes and ketones may be derivatized with 2,4-dinitrophenylhydrazine (DNPH) under acidic conditions.
  • DNPH 2,4-dinitrophenylhydrazine
  • HPLC-UV analysis can quantify the total amount of aldehydes and ketones which are present in a sample.
  • Conventional deodorisation temperatures are typically in excess of 220 °C, for example 240 °C to 270 °C, and typically operated for 60 to 90 minutes. Where lower than conventional temperatures are used for deodorisation as allowed by the process of the present invention, for example 160 °C to 200 °C, the time periods for deodorization may be lengthened to ensure sufficient deodorization, yet still involve less energy consumption than a conventional deodorization operated at higher temperature, for example 240 °C to 270 °C, for a shorter period. In preferred embodiments, the same or lower than conventional deodorization time periods are used in combination with the lower than conventional deodorization temperature, yet achieve the same extent of deodorization as a result of the preceding basic ionic liquid treatment.
  • the time period for the deodorization may be reduced compared to that which is conventionally used and still achieve a comparable level of deodorization as a result of the preceding basic ionic liquid treatment.
  • the basic ionic liquid treatment therefore also has the advantage that it may reduce energy consumption during a subsequent deodorization step.
  • by reducing either the temperature or time period of exposure to heat during the deodorization step then side reactions that can lead to undesirable organoleptic properties of the oil, or formation of unwanted, potentially harmful by-products, may also advantageously be reduced.
  • the temperature of the deodorization is from 160 °C to 200 °C, more preferably 170 °C to 190 °C.
  • the time periods over which deodorization is conducted at these temperatures is from 30 to 150 minutes, more preferably 45 to 120 minutes, most preferably 60 to 90 minutes.
  • the basic ionic liquid treatment according to the process of the present invention may suitably be applied to crude metal-containing glyceride oil which has not undergone any previous refining steps following oil extraction.
  • the process of the present invention may be applied to glyceride oil which has undergone at least one additional refining step prior to treatment with basic ionic liquid.
  • the at least one additional refining step is selected from bleaching and/or degumming.
  • the basic ionic liquid treatment forming part of the process of the present invention is also capable of at least partially degumming the oil and removing pigments which means that the extent of degumming and bleaching steps can be scaled back, for example, in terms of treatment time or materials.
  • the basic ionic liquid treatment forming part of the process of the present invention obviates a separate FFA neutralisation step used in a chemical refining process.
  • the basic ionic liquid treatment forming part of the process of the present invention may also be capable of reducing energy consumption in a deodorization step.
  • the basic ionic liquid treatment used in accordance with the present invention is intended to obviate the use of ion exchange resins and ultrafiltration membranes and the like for removing metal contaminants which can contribute significantly to the materials costs associated with glyceride oil refining.
  • the refining processes described herein do not comprise treatment of the glyceride oil with ion exchange resins or ultrafiltration membranes.
  • the basic ionic liquid used in contact step (i) may be regenerated from the ionic compound comprising the organic quaternary ammonium cation separated in step (ii) (where these species are different) by means of a regeneration process in order to recycle the basic ionic liquid to the refining process of the invention, if desired.
  • a regeneration process may comprise anion or cation exchange steps to obtain a basic ionic liquid comprising the desired basic anion as described hereinbefore.
  • the regeneration process comprises forming a basic ionic liquid which is choline bicarbonate from a choline-FFA salt; comprising the steps of:
  • step (b) obtaining choline bicarbonate from the reaction mixture.
  • step (a) is performed by contacting an aqueous solution comprising the choline-FFA salt with CO2 (e.g. by bubbling CO2 through the aqueous solution).
  • step (b) is performed by contacting the mixture of step (a) with a solvent which is miscible with choline bicarbonate and separating the solvent from choline bicarbonate.
  • the present invention also provides a composition
  • a composition comprising a metal-containing glyceride oil and a basic ionic liquid as described hereinbefore, with the proviso that the glyceride oil does not comprise palm oil; wherein the total concentration of metal in the composition is from 10 ppm to 10,000 ppm.
  • Preferred embodiments of other aspects of the invention relating to the nature of the anion and cation of the basic ionic liquid equally apply to this aspect of the invention. For instance, it is most that the basic ionic liquid is choline bicarbonate.
  • the present invention also provides a use of a basic ionic liquid as described hereinbefore for reducing the total metal concentration of metal- containing glyceride oil by contacting the oil with the basic ionic liquid; with the proviso that the glyceride oil does not comprise palm oil.
  • the basic ionic liquid may be used in neat form or together with a solvent as described hereinbefore.
  • the basic ionic liquid may be used for reducing the concentration of any of the metals described herein in glyceride oil.
  • the basic ionic liquid is used to treat the metal-containing glyceride oil before the glyceride oil is subjected to a heating step as part of its refining.
  • the heating step may, for instance, correspond to heating the oil to temperatures in excess of, for example, 150 °C, 200 °C or even 250 °C.
  • the heating step may therefore form part of a deodorization step.
  • the presence of iron can have a negative impact on the oil's organoleptic properties if it is present in sufficient quantities during exposure of the oil to heat, such as in a deodorization step. Therefore, it is beneficial to remove a significant amount of iron and other pro- oxidant metals by way of a treatment with the basic ionic liquid prior to the heating step.
  • Embodiments of the invention described hereinbefore may be combined with any other compatible embodiments to form further embodiments of the invention.
  • all aspects of the present invention may be applied to the treatment and refining of palm oil or glyceride oil mixtures comprising palm oil.
  • the present invention also covers processes described herein wherein the glyceride oil comprises or consists of palm oil where the process further comprises a regeneration step as described hereinbefore.
  • Example 2 metal removal by ionic liquid treatment of olive oil
  • Tables 1 and 2 demonstrate that the ionic liquid treatment in accordance with the present invention is capable of substantially reducing the concentration of metal in glyceride oils.
  • the percentage iron reduction is 94 % and 97 % respectively.
  • concentrations of copper, chromium and nickel have been reduced to sub-ppm levels as a result of the ionic liquid treatment.
  • the oils used in the above examples correspond to refined oils which have already been degummed prior to doping with metal. Therefore, although the ionic liquid treatment according to the invention has been found to at least partially degum glyceride oils, the above results demonstrate that metal removal does not rely on degumming as a means for achieving the metal removal.
  • the basic ionic liquid treatment can therefore be applied at a variety of stages in the overall process.

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Abstract

La présente invention concerne un procédé d'élimination de contaminants métalliques d'huile de glycéride et un procédé de raffinage le comprenant. En particulier, la présente invention concerne un procédé dans lequel certains liquides ioniques de base sont utilisés pour traiter l'huile de glycéride. La présente invention concerne également les utilisations du liquide ionique de base et des compositions d'huile de glycéride obtenues à partir du traitement du liquide ionique.
PCT/GB2016/051562 2015-05-27 2016-05-27 Procédé d'élimination de contaminants métalliques d'huile de glycéride et procédé de raffinage d'huile de glycéride le comprenant WO2016189330A1 (fr)

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JP2017561966A JP2018517037A (ja) 2015-05-27 2016-05-27 金属汚染物質をグリセリド油から除去する方法、及びそれを組み込んだグリセリド油を精製する方法
CN201680044213.1A CN107922881A (zh) 2015-05-27 2016-05-27 从甘油酯油中去除金属污染物的方法和包括该方法的甘油酯油精炼方法
BR112017025448A BR112017025448A2 (pt) 2015-05-27 2016-05-27 processo para remover contaminantes de metais de óleo glicerídio e um processo de refinamento de óleo glicerídeo incorporando o mesmo
PH12017502156A PH12017502156A1 (en) 2015-05-27 2017-11-27 Process for removing metal contaminants from glyceride oil and a glyceride oil refining process incorporating the same

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BR112017025448A2 (pt) 2018-08-07
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GB201509089D0 (en) 2015-07-08
GB2538759B (en) 2020-12-16

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