Method for enriching a polyglycerol fatty acid ester with a defined degree of esterification and polymerization

Abstract

The invention relates to a method for enriching a polyglycerol fatty acid ester with a defined degree of esterification and polymerization as the target product of an untreated or pre-treated starting mixture which has a polyglycerol fatty acid ester with a different degree of esterification and / or polymerization, wherein three known solubility parameters are associated with the target product, and in a first step, the starting mixture is mixed with a solvent or a solvent mixture, the target product-related relative energy difference, RED for short, of which does not equal more than 1; in a second step, the solids content or a newly formed phase is separated from the target product remaining in the solvent or solvent mixture by means of filtration, centrifugation, or other known separating steps; and in a third step, the solvent or solvent mixture is separated from the remaining target product in the form of an isolate.

Description

Process for the enrichment of a polyglyceryl fatty acid ester with a defined degree of esterification and polymerization

[0001] A process is presented for the provision of polyglyceryl fatty acid esters with a defined degree of esterification and polymerization on an industrial scale, in which a polyglyceryl fatty acid ester is enriched from a starting mixture of polyglyceryl fatty acid esters with different degrees of esterification and / or polymerization, which may also contain free polyglycerol due to the synthesis.

[0002] After synthesis, polyglyceryl fatty acid esters exist as a mixture of molecules with varying degrees of esterification. However, different degrees of polymerization, i.e., a different number of glyceryl units, are also possible. The synthesis starts with polyglycerols, which are esterified with fatty acids, regardless of whether they are saturated or unsaturated, branched or unbranched. Esterifications with both saturated and unbranched fatty acids, which usually have 6 to 22 carbon atoms, are common. The simplest polyglycerols that can be used as starting materials are linear or branched diglycerols with the molecular formula C6O5H 14which are produced synthetically in a known manner industrially, for example by reacting glycerol with 2,3-epoxy-1-propanol under base catalysis to form ether bonds or by thermal condensation under base catalysis, whereby the fraction containing mainly diglycerols can be subsequently separated.

[0003] Diglycerols can occur in three different structural isomers: the linear form, in which the ether bridge is formed between the first carbon atoms of the two glycerol molecules used; the branched form, in which the ether bridge is formed between the first carbon atom of the first and the second carbon atom of the second glycerol molecule used; and the nucleodentrimeric form, in which the ether bridge is formed between the second carbon atoms of the second glycerol molecule used. In the alkali-catalyzed condensation of two glycerol molecules, approximately 80% of the linear form is formed, and approximately 20% of the branched form, while the nucleodentrimeric form is formed only to a very small extent.

[0004] Likewise, polyglycerols with more than two and preferably up to ten glyceryl units can be used in the esterification of fatty acids. Polyglycerols are polymers and therefore exhibit a polymer distribution. This means that polyglycerols exist as mixtures. Nevertheless, polyglycerols are generally abbreviated to "PG" and provided with a subscript natural number n, which indicates the number of Polyglyceryl units of the main fraction of the mixture, i.e. "PG n ". For example, triglycerols would be given as PG3 and would have the molecular formula C9O7H20. Complete esterification with a fatty acid, for example with stearic acid, would now occur at all free hydroxyl groups of the PG n-molecule, in the case of a linear PG3, at the first and second carbon atoms of the first glyceryl unit, at the second carbon atom of the second glyceryl unit, and at the second and third carbon atoms of the third glyceryl unit. The molecular formula for this example could therefore be given as CgO H^Rs, where R would represent a fatty acid residue, in the chosen example with the molecular formula C 18 OH35.

[0005] However, the abbreviation PG(n)-Cm full ester or, where appropriate, PG(n)-Cm partial ester has also been established for the abbreviation of polyglycerols esterified with saturated unbranched fatty acids. The "n" in parentheses, similar to the name of polyglycerols, indicates the number of glyceryl units contained in the molecule, and m stands for the number of carbon atoms of the saturated fatty acid used for the esterification reaction. The n thus stands for the number of glyceryl units with the molecular formula C3O2H5R, where R can stand for a fatty acid residue or the hydrogen atom of a free hydroxyl group. PG(2)-C18 full ester would thus be polyglyceryl fatty acid full ester with the molecular formula C7809H 15o. In the case of PG partial esters, the number of fatty acid residues is averaged, with the molecular formula also indicating the fraction with the most frequently occurring esterification variants. A more precise designation for polyglyceryl fatty acid partial esters results from the additional specification of the hydroxyl number, which is a measure of the content of unesterified hydroxyl groups and thus provides information about the degree of esterification of the partial ester. The esterification reactions preferably proceed from the outside in, presumably for steric reasons. Thus, the hydroxyl groups that allow the fatty acid residue the greatest degree of freedom are esterified first.The first esterification reaction on a linear polyglycerol therefore preferably takes place at the hydroxyl group of a first carbon atom of a peripheral, one-end polyglyceryl unit, while the second esterification reaction then takes place at a hydroxyl group of a first carbon atom of a peripheral, other-end polyglyceryl unit. Subsequently, the hydroxyl groups at already esterified positions are esterified at immediately adjacent carbon positions, and so on.

[0006] Fatty acids are understood here to mean preferably aliphatic monocarboxylic acids with 6 to 22 carbon atoms, which are preferably unbranched and saturated and have an even number of carbon atoms, but also odd-numbered, branched and / or may be unsaturated. Preferred starting mixtures are those containing polyglyceryl fatty acid esters obtained from esterification with unbranched, saturated fatty acids having 14, 16, 18, 20, or 22 carbon atoms, i.e., palmitic, stearic, arachidic, or behenic acid, but also, for example, those obtained from esterification with oleic acid. The starting mixtures for the enrichment described here can be present as a direct synthesis product or as a post-synthetically created mixture of different polyglyceryl fatty acid esters.

[0007] Polyglyceryl fatty acid monoesters have become the primary focus of isolation and enrichment efforts. For example, CN 11 1233 637 A describes a method for obtaining polyglyceryl monolaurate, which involves the use of a special catalyst, Lipase 435, during the synthesis, combined with extraction with ethyl acetate. JP 2001 139679 A also discloses a combined synthesis and purification method using temperatures between 100°C and 180°C and the addition of glycidol.Despite the numerous mentions of the advantageous properties of polyglyceryl monofatty acid esters in particular as surface-active substances, such as in DE 19949 518 A1 , no general process is known to date by means of which polyglyceryl fatty acid esters with a defined degree of esterification and / or polymerization can be purified or isolated, apart from preparative chromatographic methods which are too complex to carry out for the recovery of larger quantities.

[0008] The objective is therefore to provide an enrichment process that is effective for polyglyceryl fatty acid esters with a defined degree of esterification and polymerization, preferably for polyglyceryl fatty acid esters with 2 to 10 glyceryl units and fatty acid residues with 6 to 22 carbon atoms each, regardless of the respective synthesis route. The process is considered effective if the fraction of the target product is at least 65 A% or, with pretreatment of the starting mixture, at least 80 A%. The A% specification here refers to area percentages derived from the method for determining the proportion of individual fractions of a polyglyceryl fatty acid ester mixture, which is preferably carried out using size-exclusion chromatography.Furthermore, the task is to design the process in such a way that as few practical work steps as possible are required and that an application on a scale that exceeds the quantities of preparative chromatographic processes is economically possible.

[0009] To achieve this object, a process according to claim 1 is proposed, with advantageous additions and specifications of the process emerging from the subclaims, for enriching a polyglyceryl fatty acid ester with a defined degree of esterification and polymerization as the target product from an untreated or pretreated starting mixture of polyglyceryl fatty acid esters with different degrees of esterification and / or polymerization. The starting mixture can be the product of a synthesis process or a postsynthetically produced mixture of various synthesis products. Three previously known solubility parameters are assigned to the target product, and the number of glyceryl units is preferably limited to 2 to 10, and the number of carbon atoms per fatty acid residue to 6 to 22.The process comprises three steps 1), 2) 3), in which first the starting mixture is mixed with a solvent or solvent mixture, preferably under laboratory conditions, i.e. at 20°C and a constant air pressure between 780 hPa and 1070 hPa, preferably 1013.25 hPa. The solvent or solvent mixture has solubility properties that are characterized by Hansen parameters and are known as 8D. LM , ÖP LM and 8H LM. In the solvent or solvent mixture, various bonding forces between the molecules contribute to the cohesive energy, namely dispersion forces or London interactions SD, dipolar interactions 8P and hydrogen bonds 8H. Each solvent or solvent mixture can be assigned individual Hansen parameters as values ​​for the energy density, which have already been determined for very many individual solvents and are therefore previously known, for example from Charles M. Hansen: "Hansen Solubility Parameters - A Users Handbook", Second Edition 2007, Crc Press Inc, ISBN 978-0-8493-7248-3. For solvent mixtures, the individual Hansen parameters of the solvents involved are weighted according to their volume fraction in the solvent mixture and then summed. For a mixture (G) of 70% vol. solvent 1 (LM1) with 8D L Wed | 8p L Wed | 8am LMI and 30% vol. solvent 2 (LM2) with 8D LM 21 8P LM 2 I 8H LM 2 the following Hansen parameters result for the mixture: 8D G = 0.7 x 8D L MI ■*" 0.3 x 8DLM2 SPG = 0.7 x 8P|_MI + 0.3 x 8PLM2 8HG = 0.7 x 8H|_MI + 0.3 x 8HLM2 A mixture of 70% Vol. Water with 8D W = 15.5 MPa 0,5 1 8P W = 16.0 MPa 0,5 1 8H W = 42.3 MPa 0 ' 5 and 30% vol. acetone with 8D A = 15.5 MPa 0 5 , 8P A = 10.4 MPa 0 ' 5 , and 8H A = 7.0 MPa 0 ' 5 has therefore the following Hansen parameters, which are generally given without a unit, since the unit MPa 0,5 is unnecessary in the given context: 5D G = (0.7 x 15.5) + (0.3 x 15.5) = 15.5 8P G = (0.7 x 16.0) + (0.3 x 10.4) = 14.3 8HG = (0.7 x 42.3) + (0.3 x 7.0) = 31.7 The three Hansen parameters of a solvent or solvent mixture can be represented in a three-dimensional coordinate system as a point (8D LM | 8P L M | 8H LM ). The same applies to the three solubility parameters of the target product to be enriched, (8D Z | 8P Z | 8H Z ). The solvent or solvent mixture used in step 1) of the proposed enrichment process has Hansen parameters that result in a relative energy difference, abbreviated RED, of no more than 1 with respect to the target product. The RED in this process is: with P Z 2 + 8H Z 2 ) 0,5 and Ra = (4 x (8D Z - 8D L M) 2 + (5P Z - 8P L ) 2 + (8H Z - 8H L ) 2 ) 0,5, where the solubility parameters of the target product are denoted by the index Z and the Hansen parameters of the solvent or solvent mixture are denoted by the index LM. As illustrated, point A, representing the target product, forms z the center of a sphere with radius R o , within which the point ALM representing the solvent or solvent mixture lies, where the factor 4 by which the square of the difference of the respective 8D values ​​in the expression for the R a value is multiplied, a deviation from the mathematically correct calculation of the distance between A z and A LThis deviation, which requires a stronger emphasis on the London interactions involved in the dissolution process, is preferred for the proposed enrichment process according to claim 1 based on the theoretical considerations and empirical investigations of Hansen (Charles M. Hansen, "The Three Dimensional Solubility Parameter and Solvent Diffusion Coefficient", Copenhagen, Danish Technical Press, 1967, 8.5, pages 88-90, in particular page 90, equation 8.2). Provided that a solvent or solvent mixture whose RED based on the target product is not more than 1 is mixed with the starting mixture according to claim 1, the target product, possibly alongside other components of the starting mixture, dissolves in the solvent or solvent mixture, so that the insoluble components of the starting mixture either precipitate as solids and / or form a second phase.The mixing is advantageously carried out in a reactor with a partial condenser and at. Temperatures between 10°C and 80°C, preferably between 25°C and 60°C, are stirred for up to one hour. Both the solids and the newly formed second phase are separated from the first phase in a subsequent step 2) after tempering, preferably under laboratory conditions, by means of filtration, centrifugation, or another separation method known to those skilled in the art. Finally, in step 3), the target product is separated from the solvent or solvent mixture in which it is dissolved immediately after step 2), preferably by distillation, and can remain as an isolate. The isolate can be analyzed, for example, by size exclusion chromatography for its individual components, in particular for the proportion of the target product.

[0010] The probability of increasing the yield of target product in the isolate can be increased if the solvent or solvent mixture used in step 1) has an RED based on the target product of not more than 0.5. With a constant R depending on the solubility parameters of the target product o is the probability for a smaller distance between A L M and A z is thus increased and thus ensures increased solubility of the target product in the solvent or solvent mixture used, since the solubility of the target product in the solvent or solvent mixture increases the closer the values ​​of the solubility parameters of the target product are to the values ​​of the Hansen parameters of the solvent or solvent mixture.

[0011] The process yield can be further increased by pretreating the starting mixture according to claim 3 before carrying out the process steps according to claim 1. For this purpose, the untreated starting mixture is mixed with water in a first step I), preferably under laboratory conditions. In the subsequent step II), the mixture prepared in step I) is stirred at 10°C to 80°C, advantageously for one hour. In the subsequent third step III), the mixture is heated to 10°C to 30°C and then, in step IV), is separated by centrifugation, filtration, or other methods known to those skilled in the art into a solids fraction or a newly formed second phase, on the one hand, and an aqueous phase, on the other hand. The separated solids fraction or the newly formed second phase is then subjected to the process steps according to claim 1 as a pretreated starting mixture.

[0012] A good yield of polyglyceryl monoester is achieved if the starting mixture is pretreated according to claim 3, wherein the stirring in step II) takes place at 25°C to 60°C and the mixture is heated to 20°C to 25°C in step III). Thus, in step 3) the separation of the solvent or solvent mixture from the polyglyceryl fatty acid monoester is so successful that the isolate has an area percentage of 80 area percent (80 A%) or more as determined by size exclusion chromatography.

[0013] Pretreatment of the starting mixture has a particularly advantageous effect on the yield of polyglyceryl fatty acid monoesters when the untreated starting mixture has a comparatively high proportion of polyglycerol, since polyglycerols have good water solubility and thus their proportion in the starting mixture is effectively reduced by pretreatment of the starting mixture according to claim 3. The polyglycerols then remain predominantly in the aqueous first phase in step IV).

[0014] Preferably, the solvents acetone, acetonitrile or a mixture of both are used in step 1), if necessary mixed with water, since these three components can cover a wide range of Hansen parameters, either alone or in combination with one or two of the other two.

[0015] The method according to claim 1 can also be successfully applied if the solubility parameters of the target product, i.e., a polyglyceryl fatty acid ester, are not previously known. In this case, before beginning the enrichment according to claim 1, a small amount of the target product is obtained as a test substance in a preliminary step A) using a preparative chromatographic method, as is known to the person skilled in the art. This can be done, for example, using conventional column chromatographic purification. Suitable stationary phases for this purpose are normal phases in combination with mobile phases made of solvents such as methanol, ethyl acetate, hexane, or dichloromethane, which can be used isocratically or as a gradient. The use of automated, preparative high-pressure liquid chromatography (HPLC) to obtain the target product is also possible.Reverse-phase systems can also be used using polar mobile phases such as water, acetonitrile, methanol or isopropanol, isocratic or as a gradient. The test substance thus obtained is then mixed in a step B) in a ratio of 1000 mg / 10 ml with a solvent with previously known Hansen parameters, hereinafter referred to as HP solvent, which comes from a group of HP solvents that contains at least one protic-polar, one aprotic-polar, one aprotic-nonpolar, one halogen-containing, and one aromatic HP solvent. In a step C), The HP solvent used in step B) is assigned a score of 1 if the test substance dissolves completely, for example, by adding the prefix "Score-1" to Score-1 -HP solvent. If the test substance is incompletely dissolved in the HP solvent used, it is assigned a score of 0 in a similar manner. Steps B) and C) are repeated in step D) until the sum of the solubility score values ​​is at least 1. Surprisingly, this simple procedure is already effective if, in a subsequent step E), the respective arithmetic mean of the Hansen parameters of the Score-1 -HP solvent are assigned to the test substance and thus to the target product as the solubility parameter.

[0016] The probability of increasing the yield of the target product can be advantageously increased by repeating steps B) and C) in step D) until the sum of the solubility score values ​​is at least 3.

[0017] A further refinement, accompanied by an increase in the probability of an increased yield of the target product, is also possible if, instead of the arithmetic means of the Hansen parameters of the Score-1 HP solvents in step E), such solubility parameters of the test substance are assigned which correspond to the coordinates of the center of a sphere in Hansen space, which contains at least three of the points representing the Hansen parameters of a Score-1 HP solvent and whose radius R z = (8D Z 2 + 8P Z 2 + 8H Z 2 ) 0,5Preferably, the sphere defined by its center and radius in Hansen space does not contain any point representing the Hansen parameters of a Score-O solvent. Note that the radius R z depends on the solubility parameters. If the position of the sphere's center is changed, this also corresponds to changed solubility parameters and the radius R z changes. Once the center of the sphere is determined, the radius R also changes z no longer and the solubility parameters can be assigned to the target product. The specified radius R z then has as R o Effects on the RED according to claim 1. Even more precise and thus more targeted solubility parameters of the target product are obtained by reducing the size of the sphere by reducing its radius R z is halved.

[0018] The group of solvents with which the test substance is mixed according to step B) contains at least one protic-polar, one aprotic-polar, one aprotic-nonpolar, one halogen-containing, and one aromatic solvent. This group preferably consists of the HP solvents listed below, each of whose Hansen parameters is listed below: 1] 2-Propanol: 8Ü! = 15.8 OP! = 6.1 TBI = 16.4 2] Acetone: 8D2= 15.5 8P2= 10.4 8H2= 7.0 3] Acetonitrile: 8D3= 15.3 8P3= 18.0 8H3= 6.1 4] Diethyl ether: 8D4= 14.5 8P4= 2.9 8H4= 5.1 5] Ethanol: 8D5= 15.8 8P5= 8.8 8H5= 19.4 6] Ethyacetate: 3D6= 15.8 8P6= 5.3 8H6= 7.2 7] Iso-hexane: 8D7= 14.9 8P7= 0.0 8H7= 0.0 8] Methanol: 3D8= 15.1 8P8= 12.3 3H8= 22.3 9] Methylene dichloride: 8D9= 18.2 8P9= 6.3 8H9= 6.1 10] Tetrahydrofuran: 8Dio = 16.8 8P 10 = 5.7 8H 10 = 8.0 11] Toluene: 8Dn = 18.0 8Pn = 1.4 8Hn = 2.0 12] Water: 8D 12 = 15.5 8P12 = 16.0 8H 12 = 42.3 Table 1 This group covers a broad spectrum of solubility for polyglyceryl fatty acid esters, with the result that the target products, whose solubility parameters are not previously known, can be precisely positioned in the Hansen space with little effort based on their solubility parameters, and thus a feature characteristic of the target product is available which enables effective application of the enrichment process presented according to claim 1 or 2, with yields in many cases of 80 A% or more.

[0019] It has proven advantageous not only to use pure solvents in step 1) of the enrichment process, but also to mix solvents with each other to achieve an optimal approximation of the solubility parameters of the target product. For example, by mixing solvents such as acetone and water in a ratio of 80:20 or acetonitrile and water in a ratio of 88:12, based on PG(4)C14 as the target product, it is possible to achieve an RED that is lower than the respective RED of the individual solvents. In this way, the dissolving power of the solvent or solvent mixture for a target product with known solubility parameters can be advantageously optimized without practical effort.

[0020] For example, the target product has the following solubility parameters: 8D Z = 15.0, 8P Z = 16.0, 8H Z = 23.0. Then R o = 31.78. The Hansen parameters of acetone (LM-1), acetonitrile (LM-2) and water (LM-3) are: LM-1 : 8D, = 15.5, SPT = 10.4, SHT = 7.0 with Ra = 16.68 and a RED = 0.5248; LM-2: 8D2= 15.3, 8P2= 18.0, 8H2= 6.1 with Ra = 17.22 and a RED = 0.5419; LM-3: 8D3= 15.5, 8P3= 16.0, 8H3= 42.3 with Ra = 19.35 and a RED = 0.6089. Mixture LM-4 consists of acetone and water in a ratio of 80:20, mixture LM-5 of acetonitrile and water in a ratio of 88:12. This results in the following values: LM-4: 8D4= 15.5, 8P4= 11.5, 8H4= 14.1 with Ra = 9.65 and a RED = 0.3035; LM-5: 8D5= 15.3, 8P5= 17.8, 8H5= 10.4 with Ra = 12.93 and a RED = 0.4067. The solvent mixtures listed here as examples therefore have a smaller RED than the respective REDs of their individual components and are therefore better suited for the enrichment process.

[0021] If the starting mixture comprises one of the following polyglyceryl fatty acid ester mixtures, good results are obtained by applying the process according to claim 1 or one of the subclaims with regard to the enrichment of the respective monoester, wherein polyglyceryl fatty acid esters esterified with three or more fatty acids are marked with the attribute "poly" immediately before the designation of the fatty acid residue: 1. Tetraglyceryl myristate (PG(4)-C14), comprising tetraglycerol, tetraglyceryl monomyristate in a proportion of not more than 10 A%, tetraglyceryl dimyristate, tetraglyceryl polymyristate; 2. Tetraglyceryl myristate (PG(4)-C14), comprising tetraglycerol, tetraglyceryl monomyristate in a proportion of 10 A% to 20 A%, tetraglyceryl dimyristate, tetraglyceryl polymyristate; 3. Tetraglyceryl myristate (PG(4)-C14), comprising tetraglycerol, tetraglycerol monomyristate in a proportion of 20 A% to 30 A%, tetraglyceryl dimyristate, tetraglyceryl polymyristate; 4. Tetraglyceryl stearate (PG(4)-C18) comprising tetraglycerol, tetraglyceryl monostearate in a proportion of 10 A% to 20 A%, tetraglyceryl distearate, tetraglyceryl polystearate; 5. Hexaglyceryl palmitate (PG(6)-C16), comprising hexaglycerol, 10 A% to 20 A% hexaglyceryl monopalmitate, hexaglyceryl dipalmitate and hexaglyceryl polypalmitate; 6. Hexaglyceryl palmitate (PG(6)-C16), comprising hexaglycerol, 30 A% to 40 A% hexaglyceryl monopalmitate, hexaglyceryl dipalmitate, hexaglyceryl polypalmitate; 7. Triglyceryl behenate (PG(3)-C22), comprising triglycerol, triglyceryl monobehenate in a proportion of not more than 10 A%, triglyceryl dibehenate, triglyceryl polybehenate; 8. Tetraglyceryl oleate (PG(4)-C18-1), comprising tetraglycerol, tetraglyceryl monooleate in a proportion of less than 10 A%, tetraglyceryl dioleate, tetraglyceryl polyoleate. 9. Tetraglyceryl oleate (PG(4)-C18-1), comprising tetraglycerol, tetraglyceryl monooleate in a proportion of 10 A% to 20 A%, tetraglyceryl dioleate, tetraglyceryl polyoleate; 10. Tetraglyceryl oleate (PG(4)-C18-1), comprising tetraglycerol, tetraglyceryl monooleate in a proportion of 20 A% to 30 A%, tetraglyceryl dioleate, tetraglyceryl polyoleate. 11. Tetraglyceryl isostearate (PG(4)-C18-iso), comprising tetraglycerol, tetraglyceryl monoisostearate in a proportion of less than 10 A%, tetraglyceryl diisostearate, tetraglyceryl polyisostearate. 12. Tetraglyceryl isostearate (PG(4)-C18-iso), comprising tetraglycerol, tetraglyceryl monoisostearate in a proportion of 10 A% to 20 A%, tetraglyceryl diisostearate, tetraglyceryl polyisostearate.

[0022] The method presented will be explained in more detail below using an example without being limited to this, particularly since one of the strengths of the method lies in its applicability to a wide variety of starting mixtures containing polyglyceryl fatty acid esters:

[0023] Example The target product is tetraglyceryl monomyristate, abbreviated PG(4)-C14 with the lUPAC name 3-(3-(3-(2,3-dihydroxypropoxy)-2-hydroxypropoxy)-2-hydroxypropoxy)-2-hydroxypropyl tetradecanoate, the molecular formula C26H 52 OIO and molecular weight 524.69 as shown in Fig. 1 with structural formula. Fig. 2 shows triglyceryl monostearate, abbreviated PG(3)-C18 with the IUPAC name 3-(3-(2,3-dihydroxypropoxy)-2-hydroxypropoxy)-2-hydroxypropyl stearate, molecular formula C27H54O8 and molecular weight 506.72, to show another molecule that could be subjected to the described enrichment process in a similar manner as explained in more detail here for PG(4)-C14. Assignment of the solubility parameters of the target product according to claim 8: 500 mg of PG(4)-C14 monoester are mixed with 5 ml of the appropriate solvent (Table 2) in a 10 ml Falcon tube. The samples are inverted for 24 h under laboratory conditions in an overhead shaker. The solubility is then determined visually. Solubility is determined with a score of 1 for soluble and a score of 0 for insoluble. Based on the solvent score of 1, the mean of the HSP values ​​and thus the HSP values ​​for the ester to be enriched are determined: Table 2 Based on the mean values, the following solvent mixture was determined for the enrichment of the PG(4)-C14 ester based on acetone and water: Table 3 Enrichment according to claim 1: In a reactor with a condenser, 100 g of PG(4)-C14 ester was suspended in 1000 ml of a 50 / 50 acetone / water mixture and then stirred for 1 h at 50 °C. After the suspension was cooled to room temperature, the solid was removed from the solution by filtration. The solvent / water mixture was removed by vacuum distillation, and the resulting residue was dried under vacuum. The product was obtained as a viscous liquid (20 g). Composition before and after enrichment Table 4 Pretreatment with water according to claim 3: In a reactor with a condenser, 100 g of PG(4)-C14 ester was suspended in 1500 ml of water and then stirred for 1 h at 50 °C. After the suspension was cooled to 20 °C, the solid was removed from the solution by filtration. The solid was dried in vacuo. The product was obtained as a white solid (90 g). Table 5 In a reactor with a condenser, 100 g of the pretreated PG(4)-C14 ester mixture is suspended in 1000 ml of a 50 / 50 acetone / water mixture and then stirred for 1 h at 50 °C. After the suspension is cooled to 20 °C, the solid is removed from the solution by filtration. The solvent-water mixture is removed by vacuum distillation, and the resulting residue is dried under vacuum. The product is obtained as a viscous liquid (20 g). Table 6

Claims

CLAIMS 1. A process for the enrichment of a polyglyceryl fatty acid ester with a defined degree of esterification and polymerization as the target product from an untreated or pretreated starting mixture containing polyglycerol fatty acid esters with different degrees of esterification and / or polymerization, wherein the target product is assigned three previously known solubility parameters, characterized by the following steps: 1) Mixing the starting mixture with a solvent or solvent mixture whose relative energy difference, abbreviated RED, with respect to the target product is not more than 1, 2) Separation of the solid fraction or a newly formed phase from the target product remaining in the solvent or solvent mixture by means of filtration, centrifugation or other known separation steps; 3) Separation of the solvent or solvent mixture from the target product remaining as an isolate.

2. Process according to claim 1, characterized in that the RED of the solvent or solvent mixture in step 1) based on the target product is not more than 0.

5.

3. Process according to claim 1 or 2, characterized by polyglycerols in the untreated starting mixture and the following additional steps for pretreating the starting mixture: I) Mixing the untreated starting mixture with water; II) stirring the mixture prepared in step I) at 10°C to 80°C; III) Tempering the mixture stirred in step II) to 10°C to 30°C; IV) Providing the solids portion of the mixture from step III) or a second phase newly formed in step III) as a pretreated starting mixture for the subsequent steps 1), 2) and 3) after separation of the aqueous first phase.

4. Process according to claim 3, characterized in that the target product is a polyglyceryl fatty acid monoester, that in step II) the stirring of the mixture prepared in step I) takes place at 25°C to 60°C, that in step III) the mixture is heated to 20°C to 25°C, that in step 3) the solvent or solvent mixture is separated from the polyglyceryl fatty acid monoester.

5. Process according to one of claims 3 or 4, characterized in that the untreated starting mixture comprises free polyglycerol, which remains predominantly in the aqueous first phase of step IV).

6. Process according to one of the preceding claims, characterized in that the solvent or solvent mixture in step 1) comprises either acetone or acetonitrile or both.

7. Process according to one of the preceding claims, characterized in that the solvent mixture in step 1) comprises water.

8. A method according to any one of the preceding claims, characterized by the following steps, preceding the remaining steps, for determining the solubility parameters of the target product: A) Isolation of the target product as a test substance by means of a chromatographic preparative procedure or another known method; B) Mixing the test substance in a ratio of 1000 mg / 10 ml with a solvent with previously known Hansen parameters, referred to as HP solvent, from a group containing at least one protic-polar, one aprotic-polar, one aprotic-nonpolar, one halogen-containing and one aromatic HP solvent; C) Assigning a solubility score of 1 to the HP solvent used in step B), hereinafter Score 1 HP solvent, in the case of residue-free dissolution and a solubility score of 0 in the case of incomplete dissolution of the test substance in step B); D) repeating steps B) and C) until the sum of the solubility scores is at least 1; E) Assignment of the respective arithmetic mean of the Hansen parameters of the Score-1 HP solvents to the test substance as the solubility parameter of the target product.

9. The method according to claim 8, characterized in that the repetition of steps B) and C) in step D) takes place until the sum of the values of the solubility scores is at least 3.

10. The method according to claim 9, characterized in that in step E) instead of the arithmetic mean of the Hansen parameters of the Score-1 HP solvents of the test substance, solubility parameters are assigned which correspond to the coordinates of the center of a sphere in Hansen space, which contains at least three points representing the Hansen parameters of the Score-1 HP solvents and whose radius R z = (8D Z 2 + 8P Z 2 + 8H Z 2 ) 0,5 is 8D Z , 8P Z and 8H Z as coordinates of the center of the sphere.

11. Method according to claim 10, characterized in that R z compared to step E) according to claim 10 and thus R z = 0.5 x (5D Z 2 + 8P Z 2 + 8H Z 2 ) 0,5 is.

12. The method according to any one of claims 8 to 11, characterized in that the group in step B) comprises the following HP solvents, each of which is assigned the previously known Hansen parameters: [1] 2-Propanol: SDT = 15.8 SPT = 6.1 SHT = 16.4 [2] Acetone: 5D2= 15.5 8P2= 10.4 8H2= 7.0 [3] Acetonitrile: 8D3= 15.3 8P3= 18.0 8H3= 6.1 [4] Diethyl ether: 8D4= 14.5 8P4= 2.9 8H4= 5.1 [5] Ethanol: 8D5= 15.8 8P5= 8.8 8H5= 19.4 [6] Ethyacetate: 8D6= 15.8 8P6= 5.3 8H6= 7.2 [7] Iso-hexane: 8D7= 14.9 8P7= 0.0 8H7= 0.0 [8] Methanol: 8D8= 15.1 8P8= 12.3 8H8= 22.3 [9] Methylene dichloride: 8D9= 18.2 SP9= 6.3 8H9= 6.1 [10] Tetrahydrofuran: 3D 10 = 16.8 8P 10 = 5.7 8H 10 = 8.0 [11] Toluene: 3Dn = 18.0 8Pn = 1.4 SHn = 2.0 [12] Water: 8DI2= 15.5 8P 12 = 16.0 8H 12 = 42.3 13. Method according to one of claims 8 to 12, characterized in that the Hansen parameters of the solvent mixture in step 1) correspond to the sum of the Hansen parameters of the solvents contained, weighted according to their respective volume fraction.

14. Process according to one of the preceding claims, characterized in that the RED of the solvent mixture in step 1) has a lower value than each of the solvents contained in the solvent mixture alone.

15. A process according to any one of the preceding claims, wherein the number of glyceryl units of the target product is limited to 2 to 10 and the number of carbon atoms per fatty acid residue is limited to 6 to 22, characterized in that the starting mixture comprises a polyglyceryl fatty acid partial ester mixture from the following group, wherein polyglycerol fatty acid esters esterified with three or more fatty acids are marked with the attribute "poly" immediately before the designation of the fatty acid residue:

1. Tetraglyceryl myristate (PG(4)-C14), comprising tetraglycerol, tetraglyceryl monomyristate in a proportion of not more than 10 A%, tetraglyceryl dimyristate, tetraglyceryl polymyristate; 2. Tetraglyceryl myristate (PG(4)-C14), comprising tetraglycerol, tetraglyceryl monomyristate in a proportion of 10 A% to 20 A%, tetraglyceryl dimyristate, tetraglyceryl polymyristate; 3. Tetraglyceryl myristate (PG(4)-C14), comprising tetraglycerol, tetraglycerol monomyristate in a proportion of 20 A% to 30 A%, tetraglyceryl dimyristate, tetraglyceryl polymyristate; 4. Tetraglyceryl stearate (PG(4)-C18) comprising tetraglycerol, tetraglyceryl monostearate in a proportion of 10 A% to 20 A%, tetraglyceryl distearate, tetraglyceryl polystearate; 5. Hexaglyceryl palmitate (PG(6)-C16), comprising hexaglycerol, 10 A% to 20 A% hexaglyceryl monopalmitate, hexaglyceryl dipalmitate and hexaglyceryl polypalmitate; 6. Hexaglyceryl palmitate (PG(6)-C16), comprising hexaglycerol, 30 A% to 40 A% hexaglyceryl monopalmitate, hexaglyceryl dipalmitate, hexaglyceryl polypalmitate; 7. Triglyceryl behenate (PG(3)-C22), comprising triglycerol, triglyceryl monobehenate in a proportion of not more than 10 A%, triglyceryl dibehenate, triglyceryl polybehenate; 8. Tetraglyceryl oleate (PG(4)-C18-1), comprising tetraglycerol, tetraglyceryl monooleate in a proportion of less than 10 A%, tetraglyceryl dioleate, tetraglyceryl polyoleate.

9. Tetraglyceryl oleate (PG(4)-C18-1), comprising tetraglycerol, tetraglyceryl monooleate in a proportion of 10 A% to 20 A%, tetraglyceryl dioleate, tetraglyceryl polyoleate; 10. Tetraglyceryl oleate (PG(4)-C18-1), comprising tetraglycerol, tetraglyceryl monooleate in a proportion of 20 A% to 30 A%, tetraglyceryl dioleate, tetraglyceryl polyoleate; 11. Tetraglyceryl isostearate (PG(4)-C18-iso), comprising tetraglycerol, tetraglyceryl monoisostearate in a proportion of less than 10 A%, tetraglyceryl diisostearate, tetraglyceryl polyisostearate; 12. Tetraglyceryl isostearate (PG(4)-C18-iso), comprising tetraglycerol, tetraglyceryl monoisostearate in a proportion of 10 A% to 20 A%, tetraglyceryl diisostearate, tetraglyceryl polyisostearate.

Images