Alkyl branched fatty acid separation

Abstract

The present invention relates to a method for separating alkyl branched fatty acids from a fatty acid mixture comprising alkyl branched fatty acids and linear fatty acids. The present inventors have demonstrated that a three-stage separation process is necessary to isolate the alkyl branched fatty acids in sufficient purity and recovery.

Description

PT-2125-WO-PCT ALKYL BRANCHED FATTY ACID SEPARATION CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of European Application No.24179010.4, filed May 30, 2024, which is incorporated by reference herein in its entirety. FIELD OF THE INVENTION

[0002] The present invention relates to a process for separating alkyl branched fatty acids from a fatty acid mixture comprising linear and branched fatty acids. BACKGROUND OF THE INVENTION

[0003] Isostearic acid is a saturated branched fatty acid containing 18 carbons, which, together with its derivatives, are used in multiple sectors such as industrial lubricants, personal care, and home care products. Isostearic acid derivatives have excellent flow properties compared to saturated straight chain fatty acids while being more chemically stable compared to unsaturated fatty acids. Isostearic acid is typically produced from natural oils, such as rapeseed oil or sunflower oil and, since isostearic acid and its derivatives are biodegradable, the market demand for these products has increased in the current push by the chemical industry to transition away from fossil- based products to bio-based products.

[0004] Isostearic acid is produced through a dimerization process followed by a splitting process. After being separated from the dimers, the monomer stream is a mixture of alkyl branched and straight chain fatty acids. These alkyl branched fatty acids, including isostearic acid, need to be separated from the straight chain isomers, including stearic acid, before they can be processed into downstream ester and amide products.

[0005] Commercially, isostearic acid is purified by the so-called Emersol process. In the Emersol process the fatty acid mixture is dissolved in organic solvent and then cooled down using horizontal scraped crystallisers. The linear fatty acid crystals which are formed during cooling are removed from the unsaturated linear fatty acids, unsaturated alkyl branched fatty acids and saturated alkyl branched fatty acids with a rotary drum filter. The solvent is then removed from both the fractions in a distillation step. The Emersol process suffers from many disadvantages. It is energy intensive, has high operational costs, and requires the use of undesirable organic solvent.

[0006] Alternative separation technologies exist for the separation of alkyl branched fatty acids, such as hydrophilization, urea complexation or dry fractionization.PT-2125-WO-PCT

[0007] WO2005 / 030693A1 discloses a dry fractionization process of a mixture comprising linear and branched fatty acids using a single crystallization step.

[0008] EP0332001B1 discloses hydrophilization as separation technique for the isolation of branched fatty acids. However, this requires the addition and subsequent removal of a surfactant and water or another diluent to and from the desired isostearic acid product, which adds complexity to the process design and requires disposal of used surfactant.

[0009] US5347023A1 discloses the use of urea and methanol; The addition and removal of urea creates similar problems to hydrophilization, wherein the waste urea needs to be disposed and adds complexity to the overall process.

[0010] However, none of the aforementioned processes results in the isolation of isostearic acid in the desired purity without the need of an energy intensive process and the use of undesirable organic solvents.

[0011] Hence, there remains a need to provide an efficient process for separating alkyl branched fatty acids from a fatty acid mixture comprising linear and branched fatty acids.

[0012] It is an object of the present invention to provide a multistage separation process for the isolation of alkyl branched fatty acids from a mixture of fatty acids. SUMMARY OF THE INVENTION

[0013] The present invention relates to a process for separating alkyl branched fatty acids from a fatty acid mixture comprising the steps of: a) providing a fatty acid mixture comprising alkyl branched fatty acids and linear fatty acids; b) subjecting the fatty acid mixture to a first crystallization step resulting in a first solid product and a first liquid product, c) subjecting the first solid product and the first liquid product to a first separation step; d) subjecting the first liquid product to a second crystallization step resulting in a second solid product and a second liquid product, and subjecting the first solid product to a stripping step resulting in a third solid product and a third liquid product; e) subjecting the second solid product and the second liquid product to a second separation step, wherein the second liquid product comprises more than 80 wt.% of alkyl branched fatty acids relative to the total weight of the second liquid product, and subjecting the third solid product and the third liquid product to a third separation step,PT-2125-WO-PCT wherein the third solid product comprises less than 35 wt.%, preferably less than 30 wt.% of alkyl branched fatty acids relative to the total weight of the third solid product; and f) recycling of the second solid product and the third liquid product to the fatty acid mixture of step a).

[0014] The present inventors have surprisingly found that a three-stage separation process, wherein each separation step occurs at a specific temperature range, results in the isolation of alkyl branched fatty acids, from a fatty acid mixture comprising linear fatty acids, such as stearic acid, and alkyl branched fatty acids, such as isostearic acid, in similar purity but higher recovery as compared to a conventional solvent separation process, as demonstrated in the appended examples. Moreover, the process of the invention requires less energy since there is no need to recover the organic solvent in a distillation unit. Finally, the need of a refrigeration solvent is reduced significantly.

[0015] Without wishing to be bound by any theory the present inventors believe that the three-stage separation process and recycling of the second solid product and the third liquid product is needed to afford the isolated alkyl branched fatty acids in the required yield and purity.

[0016] Representative features of the invention are set out in the following clauses, which stand alone or may be combined, in any combination, with one or more features disclosed in the text and / or drawings of the specification. 1. A process for separating alkyl branched fatty acids from a fatty acid mixture comprising the steps of: a) providing a fatty acid mixture comprising alkyl branched fatty acids and linear fatty acids; b) subjecting the fatty acid mixture to a first crystallization step resulting in a first solid product and a first liquid product, wherein the first crystallization step occurs between 20 and 40 °C, preferably between 22 and 35 °C, more preferably between 25 and 30 °C; c) subjecting the first solid product and the first liquid product to a first separation step; d) subjecting the first liquid product to a second crystallization step resulting in a second solid product and a second liquid product, wherein the second crystallization step occurs between 5 and 20 °C, preferably between 8 and 18 °C, more preferably between 10 and 15 °C, andPT-2125-WO-PCT subjecting the first solid product to a stripping step resulting in a third solid product and a third liquid product, wherein the stripping step occurs between 35 and 55 °C, preferably between 38 and 52 °C, more preferably between 42 and 50 °C; e) subjecting the second solid product and the second liquid product to a second separation step, wherein the second liquid product comprises more than 80 wt.% of alkyl branched fatty acids relative to the total weight of the second liquid product, and subjecting the third solid product and the third liquid product to a third separation step, wherein the third solid product comprises less than 30 wt.% of alkyl branched fatty acids relative to the total weight of the third solid product; and f) recycling of the second solid product and the third liquid product to the fatty acid mixture of step a). 2. Process according to clause 1, wherein the fatty acid mixture comprises - more than 50 wt.% of alkyl branched fatty acids, more preferably more than 60 wt.%, most preferably more than 65 wt.%, relative to the total weight of the fatty acid mixture, and - less than 40 wt.% of linear fatty acids, more preferably less than 30 wt.%, most preferably less than 20 wt.% relative to the total weight of the fatty acid mixture. 3. Process according to clause 1 or 2, wherein the fatty acid mixture provided in step a) has a temperature between 60 and 80 °C, preferably between 65 and 75 °C, more preferably between 68 and 72 °C. 4. Process according to any one of clauses 1-3, wherein the first crystallization, second crystallization step and / or stripping step occurs in a crystallizer, preferably a solid layer crystallizer or a suspension crystallizer. 5. Process according to any one of clauses 1-4, wherein the crystallizer is a suspension crystallizer being a stirred tank crystallizer or a tubular crystallizer, preferably a stirred tank crystalliser.PT-2125-WO-PCT 6. Process according to any one of clauses 1-5, wherein the first, second and / or third separation step occurs with a filter press, by centrifugation or with a wash column, preferably with a filter press. 7. Process according to any one of clauses 1-6, wherein the first liquid product comprises - between 80 and 99 wt.% of alkyl branched fatty acids, more preferably between 82 and 95 wt.%, most preferably between 85 and 90 wt.%, relative to the total weight of the first liquid product; and - between 5 and 20 wt.% of linear fatty acids, preferably between 10 and 18 wt.%, most preferably between 12 and 15 wt.%, relative to the total weight of the first liquid product. 8. Process according to any one of clauses 1-7, wherein the first solid product comprises - between 25 and 50 wt.% of alkyl branched fatty acids, more preferably between 30 and 45 wt.%, most preferably between 35 and 40 wt.%, relative to the total weight of the first solid product; and - between 50 and 75 wt.% of linear fatty acids, preferably between 55 and 70 wt.%, most preferably between 60 and 65 wt.%, relative to the total weight of the first solid product. 9. Process according to any one of clauses 1-8, wherein the second liquid product comprises - between 80 and 99 wt.% of alkyl branched fatty acids, more preferably between 85 and 95 wt.%, most preferably between 88 and 92 wt.%, relative to the total weight of the second liquid product; and - between 1 and 20 wt.% of linear fatty acids, preferably between 5 and 15 wt.%, most preferably between 8 and 12 wt.%, relative to the total weight of the second liquid product. 10. Process according to any one of clauses 1-9, wherein the second solid product comprises - between 55 and 75 wt.% of alkyl branched fatty acids, more preferably between 60 and 70 wt.%, most preferably between 62 and 65 wt.%, relative to the total weight of the second solid product; andPT-2125-WO-PCT - between 20 and 50 wt.% of linear fatty acids, preferably between 25 and 45 wt.%, most preferably between 30 and 40 wt.%, relative to the total weight of the second solid product. 11. Process according to any one of clauses 1-10, wherein the third liquid product comprises - between 60 and 85 wt.% of alkyl branched fatty acids, more preferably between 65 and 80 wt.%, most preferably between 70 and 75 wt.%, relative to the total weight of the third liquid product; and - between 15 and 40 wt.% of linear fatty acids, preferably between 20 and 35 wt.%, most preferably between 25 and 30 wt.%, relative to the total weight of the third liquid product. 12. Process according to any one of clauses 1-11, wherein the third solid product comprises - between 5 and 30 wt.% of alkyl branched fatty acids, more preferably between 10 and 25 wt.%, most preferably between 15 and 20 wt.%, relative to the total weight of the third solid product; and - between 70 and 95 wt.% of linear fatty acids, preferably between 75 and 90 wt.%, most preferably between 80 and 85 wt.%, relative to the total weight of the third solid product. 13. Process according to any one of clauses 1-12, wherein the alkyl branched fatty acids are C12-C24 alkyl branched fatty acids, more preferably C14-C22 alkyl branched fatty acids, even more preferably alkyl branched C16- C22 fatty acids; and wherein the linear fatty acids are C12-C24 linear fatty acids, preferably C14-C22 linear fatty acids, most preferably C16-C22 linear fatty acids. 14. Process according to any one of clauses 1-13, wherein more than 50%, preferably more than 55%, even more preferably more than 60%, most preferably more than 65% of the second liquid product is recovered, relative to the total weight of the fatty acid mixture. 15. Process according to any one of clauses 1-14 being a continuous process.PT-2125-WO-PCT BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1: Schematic of the single stage separation model with its important inputs and outputs.

[0018] Figure 2: Process schematic for a single stage separation process consisting of crystallization and filtration.

[0019] Figure 3: Isostearic product purity and recovery as a function of the target temperature in the single stage process.

[0020] Figure 4: Three process concepts for a 2-stage separation process. a) purification without recycle b) purification with recycle c) stripping with recycle, wherein each stage consists of crystallization and filtration.

[0021] Figure 5: three-stage separation process concept.

[0022] Figure 6: branched fatty acid product recovery as a function of the stripping stage temperature.

[0023] Figure 7: Recycle: fresh feed ratio as a function of the feed stage temperature for stripping stage temperature = 50 °C.

[0024] Figure 8: Process flowsheet of the three-stage separation process showing the flowrates and composition of each stream and the operating temperatures of each stage (BFA = branched fatty acids). DETAILED DESCRIPTION

[0025] The term "comprising", as used herein and in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It needs to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression "a composition comprising components A and B" should not be limited to compositions consisting only of components A and B. It means that with respect to the present invention, the only relevant components of the composition are A and B. Accordingly, the terms "comprising" and "including" encompass the more restrictive terms "consisting essentially of" and "consisting of". Method

[0026] In a first aspect of the invention a process is provided for separating alkyl branched fatty acids from a fatty acid mixture comprising the steps of:PT-2125-WO-PCT a) providing a fatty acid mixture comprising alkyl branched fatty acids and linear fatty acids; b) subjecting the fatty acid mixture to a first crystallization step resulting in a first solid product and a first liquid product, wherein the first crystallization step occurs between 20 and 40 °C, preferably between 22 and 35 °C, more preferably between 25 and 30 °C; c) subjecting the first solid product and the first liquid product to a first separation step; d) subjecting the first liquid product to a second crystallization step resulting in a second solid product and a second liquid product, wherein the second crystallization step occurs between 5 and 20 °C, preferably between 8 and 18 °C, more preferably between 10 and 15 °C, and subjecting the first solid product to a stripping step resulting in a third solid product and a third liquid product, wherein the stripping step occurs between 35 and 55 °C, preferably between 36 and 52 °C, more preferably between 38 and 50 °C; e) subjecting the second solid product and the second liquid product to a second separation step, wherein the second liquid product comprises more than 80 wt.% of alkyl branched fatty acids relative to the total weight of the second liquid product, and subjecting the third solid product and the third liquid product to a third separation step, wherein the third solid product comprises less than 35 wt.%, preferably less than 34 wt.%, more preferably less than 30 wt.% of alkyl branched fatty acids relative to the total weight of the third solid product; and f) recycling of the second solid product and the third liquid product to the fatty acid mixture of step a). Step a)

[0027] The raw materials for the fatty acids present in the fatty acid mixture provided in step a) used in the present invention are preferably naturally occurring materials such as triglyceride oils and can be of animal (e.g., tallow) or preferably of vegetable origin. Such triglyceride oils may be hydrolysed by methods known in the art to make differing mixtures of free fatty acids depending on the fatty acid profile of the starting oil. Suitable fatty acids include sunflower fatty acids, soybean fatty acids, olive fatty acids, rapeseed fatty acids, linseed fatty acids, cottonseed fatty acids, safflower fatty acids, tall oil fatty acids and tallow olein. RelativelyPT-2125-WO-PCT pure unsaturated fatty acids such as oleic acid, linoleic acid, linolenic acid, palmitoleic acid, and elaidic acid may be isolated, or relatively crude unsaturated fatty acid mixtures employed. Suitable unsaturated fatty acids are commercially available. These unsaturated fatty acids may be catalytically isomerized or are subjected to a catalytic or thermal dimerization process. One of the side products of the dimerization process is known as the monomer fraction which is a complex fatty acid mixture of unsaturated alkyl branched fatty acids, saturated alkyl branched fatty acids, saturated linear fatty acids, and unsaturated linear fatty acids. This may be the starting material for the process of the present invention and thus the fatty acid mixture provided step a).

[0028] Preferably, the fatty acid mixture provided in step a) comprises more than 90 wt.% of saturated fatty acids, more preferably more than 93 wt.%, even more preferably more than 95 wt.%, and most preferably more than 97 wt.%; and in the range from 0 to 10 wt.%%, more preferably less than 7 wt.%, even more preferably less than 5 wt.%, most preferably less than 3 wt.% by weight of unsaturated fatty acids, both relative to the total weight of the fatty acid mixture.

[0029] In the process according to the present invention the fatty acid mixture starting material is suitably initially heated so that it is in liquid state. Thus, the fatty acid mixture provided in step a) may have a temperature between 60 and 80 °C, preferably between 65 and 75 °C, more preferably between 68 and 72 °C. The fatty acid mixture may be used directly from a distillation column, in which case the temperature, for example, can be as high as 110 °C, which will require cooling to the aforementioned preferred temperature ranges prior to entering the crystallisers.

[0030] Preferably, the fatty acid mixture comprises more than 50 wt.% of alkyl branched fatty acids, more preferably more than 60 wt.%, most preferably more than 65 wt.%, relative to the total weight of the fatty acid mixture. Preferably, the fatty acid mixture comprises less than 80 wt.% of alkyl branched fatty acids, more preferably less than 75 wt.%, most preferably less than 70 wt.%, relative to the total weight of the fatty acid mixture. Preferably, the fatty acid mixture comprises between 50 and 80 wt.% of alkyl branched fatty acids, more preferably between 60 and 75 wt.%, most preferably between 65 and 70 wt.%, relative to the total weight of the fatty acid mixture.

[0031] Preferably, the fatty acid mixture comprises more than 20 wt.% of linear fatty acids, more preferably more than 25 wt.%, most preferably more than 30 wt.% relative to the total weight of the fatty acid mixture. Preferably, the fatty acid mixture comprises less than 45 wt.% of linear fatty acids, more preferably less than 40 wt.%, most preferably less than 35 wt.% relative to the total weight of the fatty acid mixture. Preferably, the fatty acid mixture comprises betweenPT-2125-WO-PCT 20 and 45 wt.% of linear fatty acids, more preferably between 25 and 40 wt.%, most preferably between 30 and 35 wt.% relative to the total weight of the fatty acid mixture.

[0032] More preferably, the fatty acid mixture comprises - between 50 and 80 wt.% of alkyl branched fatty acids, more preferably between 60 and 75 wt.%, most preferably between 65 and 70 wt.%, relative to the total weight of the fatty acid mixture; and - between 20 and 45 wt.% of linear fatty acids, more preferably between 25 and 40 wt.%, most preferably between 30 and 35 wt.%, relative to the total weight of the fatty acid mixture.

[0033] The weight ratio of the alkyl branched fatty acids to the linear fatty acids, present in the fatty acid mixture provided in step a), may be between 1:2 and 4:1, preferably between 1:1 and 3:1, more preferably between 1.5:1 and 2.5:1, most preferably between 1.9:1 and 2.1:1.

[0034] Preferably, the fatty acid mixture comprises C12-C24 fatty acids, more preferably C14-C22 fatty acids, even more preferably C16-C22 fatty acids, even more preferably C18-C20 fatty acids, most preferably C18 fatty acids.

[0035] In the context of the present invention, the alkyl branched fatty acids are preferably C12-C24 alkyl branched fatty acids, more preferably C14-C22 alkyl branched fatty acids, even more preferably alkyl branched C16-C22 fatty acids, even more preferably alkyl branched C18- C20 fatty acids, most preferably C18 alkyl branched fatty acids.

[0036] In the context of the present invention, the alkyl branched fatty acids are preferably methyl branched fatty acids.

[0037] In the context of the present invention, the linear fatty acids are preferably C12- C24 linear fatty acids, more preferably C14-C22 linear fatty acids, even more preferably C16-C22 linear fatty acids, even more preferably C18-C20 linear fatty acids, most preferably C18 linear fatty acids.

[0038] More preferably, the fatty acid mixture comprises: - between 0 to 5 wt.% preferably between 0 to 4 wt.%, more preferably between 1 to 3 wt.% of C14 fatty acids; and / or - between 5 to 30 wt.%, preferably 10 to 25 wt., more preferably 15 to 20 wt.% of C16 fatty acids; and / or - between 55 to 75 wt.%, preferably 60 to 70 wt.%, more preferably 62 to 68 wt.% of C18 fatty acids; and / orPT-2125-WO-PCT - between 0 to 20 wt.%, preferably 4 to 15 wt.%, more preferably 6 to 10 wt.% of C20 fatty acids; and / or - between 0 to 10 wt.%, preferably 1 to 8 wt.%, more preferably 1 to 4 wt.% of C22 fatty acids; - all relative to the total weight of fatty acids mixture.

[0039] Preferably, the weight ratio of C18 to C16 linear fatty acids is between 3:1 and 1:3, more preferably between 2:1 and 1:2, most preferably between 1:1 and 1:2.

[0040] Preferably, the weight ratio of C18 to C16 alkyl branched fatty acids is between 1:1 and 15:1, more preferably between 5:1 and 12:1, most preferably between 7:1 and 10:1. Step b)

[0041] The fatty acid mixture provided in step a) is subjected to a first crystallization step resulting in a first solid product and a first liquid product. wherein the first crystallization step occurs between 20 and 40 °C, preferably between 22 and 35 °C, more preferably between 25 and 30 °C.

[0042] Crystallisation of the fatty acid mixture is thus achieved by cooling the fatty acid mixture between 20 and 40 °C, preferably between 22 and 35 °C, more preferably between 25 and 30 °C. Cooling may take place in a batch-wise manner, preferably at a rate in the range from 1 to 100 °C, more preferably 2 to 65 °C, even more preferably 3 to 50 °C, and most preferably 4 to 20 °C per hour. The batch-wise cooling process preferably takes place over a time period in the range from 1 to 14, more preferably 2 to 12, even more preferably 6 to 11, and most preferably 8 to 10 hours.

[0043] Alternatively, and preferably, a continuous cooling process is utilized, maintaining a steady state configuration within the preferred temperature range. This continuous cooling approach yields a crystallization process for the fatty acid mixture similar to that achieved through batch-wise cooling.

[0044] The first crystallization step may take place in a crystallizer, preferably a solid layer crystallizer or a suspension crystallizer. Preferably, the crystallizer is a suspension crystallizer being a stirred tank crystallizer or a tubular crystallizer, preferably a stirred tank crystalliser.PT-2125-WO-PCT Step c)

[0045] During the cooling process, crystallization of the saturated linear fatty acids occurs resulting in the first solid product. The first solid product and the first liquid product are then subjected to a first separation step isolating the first solid product and the first liquid product.

[0046] The first separation step may occur with a filter press, by centrifugation or with a wash column, preferably with a filter press.

[0047] Preferably, the first liquid product comprises more than 80 wt.% of alkyl branched fatty acids, more preferably more than 82 wt.%, most preferably more than 85 wt.%, relative to the total weight of the first liquid product. Preferably, the first liquid product comprises less than 99 wt.% of alkyl branched fatty acids, more preferably less than 95 wt.%, most preferably less than 90 wt.%, relative to the total weight of the first liquid product. Preferably, the first liquid product comprises between 80 and 99 wt.% of alkyl branched fatty acids, more preferably between 82 and 95 wt.%, most preferably between 85 and 90 wt.%, relative to the total weight of the first liquid product.

[0048] Preferably, the first liquid product comprises more than 5 wt.% of linear fatty acids, more preferably more than 10 wt.%, most preferably more than 12 wt.%, relative to the total weight of the first liquid product. Preferably, the first liquid product comprises less than 20 wt.% of linear fatty acids, more preferably less than 18 wt.%, most preferably less than 15 wt.% relative to the total weight of the first liquid product. Preferably, the first liquid product comprises between 5 and 20 wt.% of linear fatty acids, preferably between 10 and 18 wt.%, most preferably between 12 and 15 wt.%, relative to the total weight of the first liquid product.

[0049] More preferably, the first liquid product comprises - between 80 and 99 wt.% of alkyl branched fatty acids, more preferably between 82 and 95 wt.%, most preferably between 85 and 90 wt.%, relative to the total weight of the first liquid product; and - between 5 and 20 wt.% of linear fatty acids, preferably between 10 and 18 wt.%, most preferably between 12 and 15 wt.%, relative to the total weight of the first liquid product.

[0050] Preferably, the first liquid product comprises more than 70 wt.% of alkyl branched fatty acids, more preferably more than 75 wt.%, most preferably more than 78 wt.%, relative to the total weight of the first liquid product. Preferably, the first liquid product comprises less than 95 wt.% of alkyl branched fatty acids, more preferably less than 90 wt.%, most preferably less than 85 wt.%, relative to the total weight of the first liquid product. Preferably, the first liquidPT-2125-WO-PCT product comprises between 70 and 95 wt.% of alkyl branched fatty acids, more preferably between 75 and 90 wt.%, most preferably between 78 and 85 wt.%, relative to the total weight of the first liquid product.

[0051] Preferably, the first liquid product comprises more than 5 wt.% of linear fatty acids, more preferably more than 10 wt.%, most preferably more than 12 wt.%, relative to the total weight of the first liquid product. Preferably, the first liquid product comprises less than 30 wt.% of linear fatty acids, more preferably less than 25 wt.%, most preferably less than 22 wt.% relative to the total weight of the first liquid product. Preferably, the first liquid product comprises between 5 and 30 wt.% of linear fatty acids, preferably between 10 and 25 wt.%, most preferably between 12 and 22 wt.%, relative to the total weight of the first liquid product.

[0052] More preferably, the first liquid product comprises - between 70 and 95 wt.% of alkyl branched fatty acids, more preferably between 75 and 90 wt.%, most preferably between 78 and 85 wt.%, relative to the total weight of the first liquid product; and - between 5 and 30 wt.% of linear fatty acids, preferably between 10 and 25 wt.%, most preferably between 12 and 22 wt.%, relative to the total weight of the first liquid product.

[0053] Preferably, the first solid product comprises more than 25 wt.% of alkyl branched fatty acids, more preferably more than 30 wt.%, most preferably more than 35 wt.%, relative to the total weight of the first solid product. Preferably, the first solid product comprises less than 50 wt.% of alkyl branched fatty acids, more preferably less than 45 wt.%, most preferably less than 40 wt.%, relative to the total weight of the first solid product. Preferably, the first solid product comprises between 25 and 50 wt.% of alkyl branched fatty acids, more preferably between 30 and 45 wt.%, most preferably between 35 and 40 wt.%, relative to the total weight of the first solid product.

[0054] Preferably, the first solid product comprises more than 50 wt.% of linear fatty acids, more preferably more than 55 wt.%, most preferably more than 60 wt.%, relative to the total weight of the first solid product. Preferably, the first solid product comprises less than 75 wt.% of linear fatty acids, more preferably less than 70 wt.%, most preferably less than 65 wt.% relative to the total weight of the first solid product. Preferably, the first solid product comprises between 50 and 75 wt.% of linear fatty acids, preferably between 55 and 70 wt.%, most preferably between 60 and 65 wt.%, relative to the total weight of the first solid product.

[0055] More preferably, the first solid product comprisesPT-2125-WO-PCT - between 25 and 50 wt.% of alkyl branched fatty acids, more preferably between 30 and 45 wt.%, most preferably between 35 and 40 wt.%, relative to the total weight of the first solid product; and - between 50 and 75 wt.% of linear fatty acids, preferably between 55 and 70 wt.%, most preferably between 60 and 65 wt.%, relative to the total weight of the first solid product.

[0056] Preferably, the first solid product comprises more than 10 wt.% of alkyl branched fatty acids, more preferably more than 15 wt.%, most preferably more than 20 wt.%, relative to the total weight of the first solid product. Preferably, the first solid product comprises less than 45 wt.% of alkyl branched fatty acids, more preferably less than 40 wt.%, most preferably less than 35 wt.%, relative to the total weight of the first solid product. Preferably, the first solid product comprises between 10 and 45 wt.% of alkyl branched fatty acids, more preferably between 15 and 40 wt.%, most preferably between 20 and 35 wt.%, relative to the total weight of the first solid product.

[0057] Preferably, the first solid product comprises more than 55 wt.% of linear fatty acids, more preferably more than 60 wt.%, most preferably more than 65 wt.%, relative to the total weight of the first solid product. Preferably, the first solid product comprises less than 90 wt.% of linear fatty acids, more preferably less than 85 wt.%, most preferably less than 80 wt.% relative to the total weight of the first solid product. Preferably, the first solid product comprises between 55 and 90 wt.% of linear fatty acids, preferably between 60 and 85 wt.%, most preferably between 65 and 80 wt.%, relative to the total weight of the first solid product.

[0058] More preferably, the first solid product comprises - between 10 and 45 wt.% of alkyl branched fatty acids, more preferably between 15 and 40 wt.%, most preferably between 20 and 35 wt.%, relative to the total weight of the first solid product; and - between 55 and 90 wt.% of linear fatty acids, preferably between 60 and 85 wt.%, most preferably between 65 and 80 wt.%, relative to the total weight of the first solid product.PT-2125-WO-PCT Step d)

[0059] The first liquid product is then subjected to a second crystallization step resulting in a second solid product and a second liquid product; and the first solid product is then subjected to a stripping step resulting in a third solid product and a third liquid product.

[0060] The second crystallization step occurs between 5 and 20 °C, preferably between 8 and 18 °C, more preferably between 10 and 15 °C. Preferably, the second crystallization step occurs between 5 and 14 °C, preferably between 6 and 13 °C, more preferably between 7 and 13 °C.

[0061] Crystallisation of the first liquid product is thus achieved by cooling the first liquid product between 5 and 20 °C, preferably between 8 and 18 °C, more preferably between 10 and 15 °C, thereby affording a second solid product and a second liquid product. Cooling may take place in a batch-wise manner, preferably at a rate in the range from 1 to 100 °C, more preferably 2 to 65 °C, even more preferably 3 to 50 °C, and most preferably 4 to 20 °C per hour. The batch- wise cooling process preferably takes place over a time period in the range from 1 to 14, more preferably 2 to 12, even more preferably 6 to 11, and most preferably 8 to 10 hours.

[0062] Alternatively, and preferably, a continuous cooling process is utilized, maintaining a steady state configuration within the preferred temperature range. This continuous cooling approach yields a crystallization process for the first liquid product similar to that achieved through batch-wise cooling. The second crystallization step may take place in a crystallizer, preferably a solid layer crystallizer or a suspension crystallizer. Preferably, the crystallizer is a suspension crystallizer being a stirred tank crystallizer or a tubular crystallizer, preferably a stirred tank crystalliser.

[0063] The stripping step occurs between 35 and 55 °C, preferably between 38 and 52 °C, more preferably between 42 and 50 °C. The stripping step may also occur between 30 and 50 °C, preferably between 35 and 45 °C, more preferably between 38 and 42 °C. Preferably, the stripping step may also occur between 41 and 48 °C, preferably between 42 and 46 °C, more preferably between 43 and 44 °C. As understood by the skilled person, the stripping step is a recrystallization step of the first solid product.

[0064] The first solid product is thus heated to a temperature as mentioned above thereby affording a third solid product and a third liquid product. Heating may take place in a batch-wise manner, preferably at a rate in the range from 1 to 100 °C, more preferably 2 to 65 °C, even more preferably 3 to 50 °C, and most preferably 4 to 20 °C per hour. The batch-wise heating processPT-2125-WO-PCT preferably takes place over a time period in the range from 1 to 14, more preferably 2 to 12, even more preferably 6 to 11, and most preferably 8 to 10 hours.

[0065] Alternatively, and preferably, a continuous heating process is utilized, maintaining a steady state configuration within the preferred temperature range. This continuous heating approach yields a stripping process for first solid product similar to that achieved through batch- wise heating. The stripping step may take place in a crystallizer, preferably a solid layer crystallizer or a suspension crystallizer. Preferably, the crystallizer is a suspension crystallizer being a stirred tank crystallizer or a tubular crystallizer, preferably a stirred tank crystalliser. Step e)

[0066] The second solid product and the second liquid product are then subjected to a second separation step isolating the second solid product and the second liquid product.

[0067] The second separation step may occur with a filter press, by centrifugation or with a wash column, preferably with a filter press.

[0068] Preferably, the second liquid product comprises more than 80 wt.% of alkyl branched fatty acids, more preferably more than 85 wt.%, most preferably more than 88 wt.%, relative to the total weight of the second liquid product. Preferably, the second liquid product comprises less than 99 wt.% of alkyl branched fatty acids, more preferably less than 95 wt.%, most preferably less than 92 wt.%, relative to the total weight of the second liquid product. Preferably, the second liquid product comprises between 80 and 99 wt.% of alkyl branched fatty acids, more preferably between 85 and 95 wt.%, most preferably between 88 and 92 wt.%, relative to the total weight of the second liquid product.

[0069] Preferably, the second liquid product comprises more than 1 wt.% of linear fatty acids, more preferably more than 5 wt.%, most preferably more than 8 wt.%, relative to the total weight of the second liquid product. Preferably, the second liquid product comprises less than 20 wt.% of linear fatty acids, more preferably less than 15 wt.%, most preferably less than 12 wt.% relative to the total weight of the second liquid product. Preferably, the second liquid product comprises between 1 and 20 wt.% of linear fatty acids, preferably between 5 and 15 wt.%, most preferably between 8 and 12 wt.%, relative to the total weight of the second liquid product.

[0070] More preferably, the second liquid product comprises - between 80 and 99 wt.% of alkyl branched fatty acids, more preferably between 85 and 95 wt.%, most preferably between 88 and 92 wt.%, relative to the total weight of the second liquid product; andPT-2125-WO-PCT - between 1 and 20 wt.% of linear fatty acids, preferably between 5 and 15 wt.%, most preferably between 8 and 12 wt.%, relative to the total weight of the second liquid product.

[0071] The weight ratio of the alkyl branched fatty acids to the linear fatty acids present in the second liquid product may be between 5:1 and 15:1, preferably between 6:1 and 10:1, more preferably between 7:1 and 10:1. More specifically, the weight ratio may be between 7:1 and 8:1 or between 8:1 and 10:1.

[0072] Advantageously, the process of invention results in a recovery of more than 50%, preferably more than 55%, most preferably more than 60% of the second liquid product relative to the total weight of the fatty acid mixture. Thus, more than 50%, preferably more than 55%, even more preferably more than 60%, most preferably more than 65% of the second liquid product relative to the total weight of the fatty acid mixture.

[0073] Preferably, the second solid product comprises more than 55 wt.% of alkyl branched fatty acids, more preferably more than 60 wt.%, most preferably more than 62 wt.%, relative to the total weight of the second solid product. Preferably, the second solid product comprises less than 75 wt.% of alkyl branched fatty acids, more preferably less than 70 wt.%, most preferably less than 65 wt.%, relative to the total weight of the second solid product. Preferably, the second solid product comprises between 55 and 75 wt.% of alkyl branched fatty acids, more preferably between 60 and 70 wt.%, most preferably between 62 and 65 wt.%, relative to the total weight of the second solid product.

[0074] Preferably, the second solid product comprises more than 20 wt.% of linear fatty acids, more preferably more than 25 wt.%, most preferably more than 30 wt.%, relative to the total weight of the second solid product. Preferably, the second solid product comprises less than 50 wt.% of linear fatty acids, more preferably less than 45 wt.%, most preferably less than 40 wt.% relative to the total weight of the second solid product. Preferably, the second solid product comprises between 20 and 50 wt.% of linear fatty acids, preferably between 25 and 45 wt.%, most preferably between 30 and 40 wt.%, relative to the total weight of the second solid product.

[0075] More preferably, the second solid product comprises - between 55 and 75 wt.% of alkyl branched fatty acids, more preferably between 60 and 70 wt.%, most preferably between 62 and 65 wt.%, relative to the total weight of the second solid product; andPT-2125-WO-PCT - between 20 and 50 wt.% of linear fatty acids, preferably between 25 and 45 wt.%, most preferably between 30 and 40 wt.%, relative to the total weight of the second solid product.

[0076] Preferably, the second solid product comprises more than 35 wt.% of alkyl branched fatty acids, more preferably more than 40 wt.%, most preferably more than 42 wt.%, relative to the total weight of the second solid product. Preferably, the second solid product comprises less than 55 wt.% of alkyl branched fatty acids, more preferably less than 50 wt.%, most preferably less than 48 wt.%, relative to the total weight of the second solid product. Preferably, the second solid product comprises between 35 and 55 wt.% of alkyl branched fatty acids, more preferably between 40 and 50 wt.%, most preferably between 42 and 48 wt.%, relative to the total weight of the second solid product.

[0077] Preferably, the second solid product comprises more than 45 wt.% of linear fatty acids, more preferably more than 50 wt.%, most preferably more than 52 wt.%, relative to the total weight of the second solid product. Preferably, the second solid product comprises less than 65 wt.% of linear fatty acids, more preferably less than 60 wt.%, most preferably less than 58 wt.% relative to the total weight of the second solid product. Preferably, the second solid product comprises between 45 and 65 wt.% of linear fatty acids, preferably between 50 and 60 wt.%, most preferably between 52 and 58 wt.%, relative to the total weight of the second solid product.

[0078] More preferably, the second solid product comprises - between 35 and 55 wt.% of alkyl branched fatty acids, more preferably between 40 and 50 wt.%, most preferably between 42 and 48 wt.%, relative to the total weight of the second solid product; and - between 45 and 65 wt.% of linear fatty acids, preferably between 50 and 60 wt.%, most preferably between 52 and 58 wt.%, relative to the total weight of the second solid product.

[0079] The third solid product and the third liquid product are then subjected to a third separation step isolating the third solid product and the third liquid product.

[0080] The third separation step may occur with a filter press, by centrifugation or with a wash column, preferably with a filter press.

[0081] Preferably, the third liquid product comprises more than 60 wt.% of alkyl branched fatty acids, more preferably more than 65 wt.%, most preferably more than 70 wt.%, relative to the total weight of the third liquid product. Preferably, the third liquid product comprises less than 85 wt.% of alkyl branched fatty acids, more preferably less than 80 wt.%, most preferably lessPT-2125-WO-PCT than 75 wt.%, relative to the total weight of the third liquid product. Preferably, the third liquid product comprises between 60 and 85 wt.% of alkyl branched fatty acids, more preferably between 65 and 80 wt.%, most preferably between 70 and 75 wt.%, relative to the total weight of the third liquid product.

[0082] Preferably, the third liquid product comprises more than 15 wt.% of linear fatty acids, more preferably more than 20 wt.%, most preferably more than 25 wt.%, relative to the total weight of the third liquid product. Preferably, the third liquid product comprises less than 40 wt.% of linear fatty acids, more preferably less than 35 wt.%, most preferably less than 30 wt.% relative to the total weight of the third liquid product. Preferably, the third liquid product comprises between 15 and 40 wt.% of linear fatty acids, preferably between 20 and 35 wt.%, most preferably between 25 and 30 wt.%, relative to the total weight of the third liquid product.

[0083] More preferably, the third liquid product comprises - between 60 and 85 wt.% of alkyl branched fatty acids, more preferably between 65 and 80 wt.%, most preferably between 70 and 75 wt.%, relative to the total weight of the third liquid product; and - between 15 and 40 wt.% of linear fatty acids, preferably between 20 and 35 wt.%, most preferably between 25 and 30 wt.%, relative to the total weight of the third liquid product

[0084] Preferably, the third liquid product comprises more than 35 wt.% of alkyl branched fatty acids, more preferably more than 40 wt.%, most preferably more than 45 wt.%, relative to the total weight of the third liquid product. Preferably, the third liquid product comprises less than 65 wt.% of alkyl branched fatty acids, more preferably less than 60 wt.%, most preferably less than 55 wt.%, relative to the total weight of the third liquid product. Preferably, the third liquid product comprises between 35 and 65 wt.% of alkyl branched fatty acids, more preferably between 40 and 60 wt.%, most preferably between 45 and 55 wt.%, relative to the total weight of the third liquid product.

[0085] Preferably, the third liquid product comprises more than 35 wt.% of linear fatty acids, more preferably more than 40 wt.%, most preferably more than 45 wt.%, relative to the total weight of the third liquid product. Preferably, the third liquid product comprises less than 65 wt.% of linear fatty acids, more preferably less than 60 wt.%, most preferably less than 55 wt.% relative to the total weight of the third liquid product. Preferably, the third liquid product comprises between 35 and 65 wt.% of linear fatty acids, preferably between 40 and 60 wt.%, most preferably between 45 and 55 wt.%, relative to the total weight of the third liquid product.PT-2125-WO-PCT

[0086] More preferably, the third liquid product comprises - between 35 and 65 wt.% of alkyl branched fatty acids, more preferably between 40 and 60 wt.%, most preferably between 45 and 55 wt.%, relative to the total weight of the third liquid product; and - between 35 and 65 wt.% of linear fatty acids, preferably between 40 and 60 wt.%, most preferably between 45 and 55 wt.%, relative to the total weight of the third liquid product.

[0087] Preferably, the third solid product comprises more than 5 wt.% of alkyl branched fatty acids, more preferably more than 10 wt.%, most preferably more than 15 wt.%, relative to the total weight of the third solid product. Preferably, the third solid product comprises less than 30 wt.% of alkyl branched fatty acids, more preferably less than 25 wt.%, most preferably less than 20 wt.%, relative to the total weight of the third solid product. Preferably, the third solid product comprises between 5 and 30 wt.% of alkyl branched fatty acids, more preferably between 10 and 25 wt.%, most preferably between 15 and 20 wt.%, relative to the total weight of the third solid product.

[0088] Preferably, the third solid product comprises more than 70 wt.% of linear fatty acids, more preferably more than 75 wt.%, most preferably more than 80 wt.%, relative to the total weight of the third solid product. Preferably, the third solid product comprises less than 95 wt.% of linear fatty acids, more preferably less than 90 wt.%, most preferably less than 85 wt.% relative to the total weight of the third solid product. Preferably, the third solid product comprises between 70 and 95 wt.% of linear fatty acids, preferably between 75 and 90 wt.%, most preferably between 80 and 85 wt.%, relative to the total weight of the third solid product.

[0089] More preferably, the third solid product comprises - between 5 and 30 wt.% of alkyl branched fatty acids, more preferably between 10 and 25 wt.%, most preferably between 15 and 20 wt.%, relative to the total weight of the third solid product; and - between 70 and 95 wt.% of linear fatty acids, preferably between 75 and 90 wt.%, most preferably between 80 and 85 wt.%, relative to the total weight of the third solid product.

[0090] Preferably, the third solid product comprises more than 5 wt.% of alkyl branched fatty acids, more preferably more than 10 wt.%, most preferably more than 15 wt.%, relative to the total weight of the third solid product. Preferably, the third solid product comprises less than 35 wt.% of alkyl branched fatty acids, more preferably less than 34 wt.%, even more preferably less than 33 wt.%, even more preferably less than 32 wt.%, even more preferably less than 31PT-2125-WO-PCT wt.%, most preferably less than 30 wt.%, relative to the total weight of the third solid product. Preferably, the third solid product comprises between 5 and 35 wt.% of alkyl branched fatty acids, more preferably between 10 and 33 wt.%, most preferably between 15 and 30 wt.%, relative to the total weight of the third solid product.

[0091] Preferably, the third solid product comprises more than 55 wt.% of linear fatty acids, more preferably more than 60 wt.%, most preferably more than 65 wt.%, relative to the total weight of the third solid product. Preferably, the third solid product comprises less than 90 wt.% of linear fatty acids, more preferably less than 85 wt.%, most preferably less than 80 wt.% relative to the total weight of the third solid product. Preferably, the third solid product comprises between 55 and 90 wt.% of linear fatty acids, preferably between 60 and 85 wt.%, most preferably between 65 and 80 wt.%, relative to the total weight of the third solid product.

[0092] More preferably, the third solid product comprises - between 5 and 35 wt.% of alkyl branched fatty acids, more preferably between 10 and 33 wt.%, most preferably between 15 and 30 wt.%, relative to the total weight of the third solid product; and - between 55 and 90 wt.% of linear fatty acids, preferably between 60 and 85 wt.%, most preferably between 65 and 80 wt.%, relative to the total weight of the third solid product.

[0093] The weight ratio of the alkyl branched fatty acids to the linear fatty acids present in the third solid product may be between 1:3 and 1:8, preferably between 1:4 and 1:7, more preferably between 1:5 and 1:6.

[0094] As appreciated by the skilled person, the first, second and third separation step may occur with a filter press, by centrifugation or with a wash column, preferably with a filter press. Step f)

[0095] The second solid product and the third liquid product is recycled to the fatty acid mixture of step a). The present inventors have found that this recycling step leads to the isolation of the second liquid product from the fatty acid mixture in a higher recovery, such as more than 50%, preferably more than 55%, even more preferably more than 60%, most preferably more than 65% of the second liquid product relative to the total weight of the fatty acid mixture.

[0096] All steps of the process as defined under the present invention can be carried out in a batch process or as a continuous process. Preferably, the process is according to the invention, wherein the process is a continuous process.PT-2125-WO-PCT

[0097] As appreciated by the skilled person, the process of subjecting the fatty acid mixture, the first liquid product and / or the first solid product to a crystallization step or a stripping step and separating of the resulting liquid and solid product is a dry fractionation step. Product-by-process

[0098] In a second aspect of the invention a second liquid product is provided obtainable from the process as defined under the first aspect of the invention.

[0099] As appreciated by the skilled person all features related to process defined under the first aspect of the invention apply mutatis mutandis to the the second liquid product obtainable by the process as defined under the second aspect of the invention. For example, all features explained under steps a)-f), such as the alkyl branched fatty acid content or the linear fatty acid content of the different products, are equally applicable to the process for producing the fat composition according to the tenth aspect of the invention.

[0100] In a third aspect of the invention a third solid product is provided obtainable from the process as defined under the first aspect of the invention.

[0101] As appreciated by the skilled person all features related to process defined under the first aspect of the invention apply mutatis mutandis to the the third solid product obtainable by the process as defined under the third aspect of the invention. For example, all features explained under steps a)-f), such as the alkyl branched fatty acid content or the linear fatty acid content of the different products, are equally applicable to the process for producing the fat composition according to the tenth aspect of the invention.

[0102] Although certain aspects of the invention have been described, the scope of the appended claims is not intended to be limited solely to these specific aspects. The claims are to be construed literally, purposively, and / or to encompass equivalents. The scope of the present invention is defined by the appended claims. One or more of the objects of the invention are achieved by the appended claims. EXAMPLES Example 1: conditions for 1-stage, 2-stage, or 3-stage separation process Process concept

[0103] The following operating conditions were optimized to maximize the performance of the different evaluated processes on the following metrics.PT-2125-WO-PCT - Purity = 90% branched fatty acids. Thus, each process concept must meet the minimum purity criteria of 90% branched fatty acids in the second liquid product. - Recovery should be between 55 and 65%. The process concepts must meet and possibly exceed this value. The higher the recovery from a process concept, the higher margin for error for kinetic and scale up limitations. - Recycle: fresh feed ratio – minimize; Higher recycle ratios will increase the flowrates to the crystallizer leading to higher crystallizer sizes, which in turn increases the cost for the process concept.

[0104] The performance of all process concepts was compared for the same process technology – suspension crystallization with high performance filtration. The liquid retention in the solid cake in the filtration step was assumed to be 10%. Single stage process model

[0105] The process model took as input the feed flowrate, composition, and the target temperature. The solidus and liquidus curve fit equations were obtained from DSC experimental results on blends of stearic acid and isostearic acid. The output showed the product purity and recovery along with the flowrates of the solid and liquid phase flowrates. The only free input variable controlled was the target temperature. The feed flowrate and composition were also affected by the performance of other stages and the actual process scheme (see Figure 1). Calculation approach Assumptions 1. Single stage operation – No recycle flows 2. Suspension crystallizer + H.P filtration (10% liquid retention) Model inputs 1. Feed composition (branched fatty acids = BFA %) = 68 wt.% 2. Feed flowrate = 100 kg / hr 3. Stage temperature = 25 °C 4. Equilibrium equations a. Solidus eqn1 (up to 72% BFA) – y = 0.0117x2– 1.653x +70 b. Solidus eqn2 – y = 0.0142x2– 3.695x +206.44 c. Liquidus eqn1 (up to 72% BFA) – y = -0.0046x2+ 0.0696x +70PT-2125-WO-PCT d. Liquidus eqn2 – y = -0.0865x2+ 11.945x -360.75

[0106] The equilibrium equations are as follows ^^^^^^^^^^^^^^^ → ^^ ൌ 0.0117^^ଶ െ 1.653^^ ^ 70 ; ^^^^^^ ^^ ^ 72 ^1^^^^^^^^^^^^^^^^^ ଶ^ → ^^ ൌ െ0.0046^^ ^ 0.0696^^ ^ 70; ^^^^^^ ^^ ^ 72 ^2^^^^^^^^^^^^^^^ଶ → ^^ ൌ 0.0142^^ଶ െ 3.695^^ ^ 206.44;^^^^^^ ^^ ^ 72 ^3^^^^^^^^^^^^^^^^^ଶ → ^^ ൌ െ0.0865^^ଶ ^ 11.945^^ െ 360.75 ^^^^^^ ^^ ^ 72 ^4^Calculation procedure Step 1 – reformulate equilibrium equations

[0107] Firstly, the limits for the equilibrium equations have been reformulated in terms of the temperature of the process i.e., limits in x values have to be translated to limits in y values. This was done by substituting the x-limits in eq.1 and eq.2 for the solidus and liquidus lines respectively. This resulted in the following limits: 1. Solidus lines a. Eq.1 for y> 11.64 b. Eq.3 for y<11.64 2. Liquidus lines a. Eq.2 for y>51.16 b. Eq.4 for y<51.16 Step 2 – Calculate the distribution coefficient

[0108] From the assumed target temperature of 25 °C and the limits determined above, it can be inferred that eq.1 and eq.4 will be applicable for the solidus and liquidus curves. The intercept of “y = 25” with these equations was found by the solving for the quadratic roots of the eq.5 and eq.6 using the formula given in eq.7 25 ൌ 0.0117^^ଶ െ 1.653^^ ^ 70 ^5^25 ൌ െ0.0865^^ଶ ^ 11.945^^ െ 360.75 ^6^^^ ൌ െ^^ േ √^^ଶ െ 4^^^^2^^^7^

[0109] Any roots below x=0 are rejected. Similarly, the roots are checked for other constraints set in eq.1-4. For the example used here, eq.5 gives x = 33.8 and eq.6 gives x = 85.7 (see Figure 2).PT-2125-WO-PCT

[0110] 36.8% and 86.6% is the branched fatty acid concentration in the solid and liquid phase respectively, in an ideal separation process. Thus, the ideal distribution coefficient can be calculated as follows. ^^^ௗ ൌ^ி^% ^^ ^^^^ௗ ^^^^^ ^ி^% ^^ ^^^௨^ௗ ^^^^^ൌ ଷ^.଼଼^.^ൌ 0.425Step 3 – calculate

[0111] Based on the assumptions described above, the effective distribution coefficient was calculated in two steps. ^^^^^ௗ^^^ି^^௬^ ൌ^^

[0112] Substituting in the equation resulted in^^^^^ି^^௬^ ൌషళ^^షఱ0.425 ^ ^1 െ 0.425^^^ି^^^^షభబ^^^^^ି^^௬^ ൌ 0.428Step 4 – Calculate ideal and actual solid phase concentration

[0113] The ideal solid phase concentration is calculated from the effective distribution coefficient. ^^^^^^ௗ,^ௗ^^^ ൌ ^^^^^ି^^௬^^^^^^ ൌ 0.428 ∗ 86.6 ൌ 37.06

[0114] Accounting for 10% liquid retention in the filtration step, the actual solid phase concentration was found ^^ ^ 0.1^^^^37.06 ^ 0.1 ∗ 86^^^^ௗ,^^௧௨^^ൌ^^^^ௗ ^^^1 ^ 0.1ൌ.61.1ൌ 41.6Step 5 – calculate recovery of solid and liquid phase

[0115] Using the lever rule the recovery of each phase was calculated. ^^ ^^ி െ ^^^ௌ ൌ^4^^5^

[0116] Substituting xf= 68, xl41.6 we get ^^ ൌ 68 െ 86.6ௌ 41.6 െ 86.6 ൌ 0.413PT-2125-WO-PCT 41.6 െ 68^^^ ൌ41.6െ 86.6 ൌ 0.587

[0117] Thus, at 25 °C with feed flowrate of 100 kg / hr and feed composition of 68%branched fatty acids, a solid of 41.3 kg / hr with 41.6% branched fatty acid content and a liquid phase stream of 58.7 kg / hr with 86.6% branched fatty acid content is obtained. Multi-stage separation approach

[0118] The approach for evaluation is similar in a multi-stage separation. However, it includes an additional step to recalculate the feed flowrate and feed composition according to the recycle flowrates and compositions of the recycle streams. Results One stage separation

[0119] In a single stage separation consisting of crystallization and filtration (see Figure 3), the achievable purity and recovery of the product are coupled. To maximize purity, recovery must be sacrificed. As can be seen in figure 4, for the target purity of 100%, the achievable recovery is <10%. This is more than 6 times lower than the target recovery. Thus, a single stage separation cannot achieve both the purity and recovery targets at the same time. Thus, it can be concluded that multistage separation is a necessity. Two stage separation

[0120] There are three possible process concepts proposed for a two-stage separation process which are (see Figure 4): a) purification of liquid product from feed stage with no recycle b) purification of liquid product from feed stage with recycle of solid phase from purification stage c) stripping of solid phase from feed stage and recycle obtained liquid product.

[0121] Due to the design approach taken in this evaluation, the product purity depends only on the stage temperature of the final stage in the process. From the phase diagram for the fatty acid mixture with increasing amounts of branched fatty acids, it can be determined that the final stage must operate at 12.2 °C or lower to meet the product purity specification. However, lower temperatures reduce the product recovery and hence, to maximize the product recovery thePT-2125-WO-PCT final stage temperature must be fixed at 12.2 °C. Thus, there is only one free variable – the operating temperature of the first stage.

[0122] Process concept b) – purification with recycle of solid phase gives the best performance among the three when considering all three metrics. The maximum recovery obtained without recycling the solid product is 49.5% which is lower than the target recovery of 55 to 65%. With recycling, the maximum recovery achievable increases to ~70%.

[0123] Comparing the purification and stripping process concept shows that while both process concepts can achieve the same purities and recoveries at similar operating temperatures. However, the stripping process concept requires higher recycle ratios (~2-4.5) compared to the purification process concept (~0.5-2), which is undesirable. Three stage separation

[0124] The three-stage separation process concept can be seen in Figure 5 consisting of the feed stage, purification and stripping stage. The three-stage separation allows for more control over the process performance as all three metrics can be decoupled from each other. The purity is controlled by the purification stage temperature and the recovery is controlled by the stripping stage temperature. The recycle ratio is dependent on the operating temperatures of all three stages. However, because the purification and stripping stage temperature are being used to control other metrics, this leaves the feed stage temperature as the only variable to control the recycle ratio. Manipulating the feed stage temperature allows for control over the recycle ratio. The overall product recovery as a function of stripping stage temperature can be seen in Figure 6. The variation in recycle ratio can be seen in Figure 7.

[0125] The optimized stage temperatures obtained from the parametric sweep gives the following results (Table 1). A rigorous numerical optimization is not carried out as these operating conditions will have to be re-optimized based on results from lab scale experimentation. Table 1: optimized stage temperatures for each separation step Stage Stage temperature (°C)PT-2125-WO-PCT Conclusion

[0126] Comparing the two-stage separation concept with either a purification or a stripping process concept shows that while both process concepts can achieve the same purities and recoveries at similar operating temperatures, but the stripping process concept requires higher recycle ratios (~2-4.5) compared to the purification process concept (~0.5-2).

[0127] In the comparison between the two-stage and three-stage separation process concepts, the decisive factor is the total flowrate processed by each concept. This is because the flowrate dictates the crystallizer's size, which subsequently influences the capital investment needed for the process. The comparison is shown in Table 2. A fresh feed flowrate of 100 kg / hr is assumed for ease of calculation. For the target recovery of 55 to 65%, the 2-stage process has a total flowrate of 222 kg / hr compared to 242 kg / hr (9% higher) of the 3-stage process. However, at the maximum recovery achieved in both the processes of 68.9%, the total flowrate in the 2- stage process increases to 575 kg / hr while the 3-stage process operates at only 276 kg / hr (52% lower). Table 2: comparison recovery of the 2-stage and 3-stage process. 2 stage process 3 stage process y

[0128] Thus, the three-stage process (see Figure 8) is more stable in terms of process flowrates for varying recoveries of the product.

[0129] The three-stage separation allows for more control over the process performance as all three metrics can be decoupled from each other. The purity is controlled by the purification stage temperature and the recovery is controlled by the stripping stage temperature. The recycle ratio is dependent on the operating temperatures of all three stages, however because the purification and stripping stage temperature are being used to control other metrics, this leaves the feed stage temperature as the only variable to control the recycle ratio. Manipulating the feed stage temperature allows for control over the recycle ratio.PT-2125-WO-PCT Example 2: composition

[0130] Table 3 shows the composition of the fatty acid mixture, the second liquid product and the third solid product that can be obtained from the aforementioned 3-stage separation process based on the calculations from Example 1. Table 3: composition of the fatty acid mixture, the second liquid product and the third solid product Component Feed Second liquid Third solid product composition product composition composition Ep y p, y p pp g p

[0131] Three different experimental setups were designed to evaluate the efficiency of each process of the first crystallization step, the second crystallization step and the stripping step for separating the alkyl branched fatty acids from the alkyl linear fatty acids. The starting material for each process step was adjusted in a specific ratio to obtain a feed in the required ratio of alkyl branched fatty acids and alkyl linear fatty acids. The crystallization or stripping and separation occurred in a jacketed stirred tank crystallizer and a membrane filter press. The temperature control was achieved using two water baths, one for the crystallizer and one for the filter press.

[0132] The experimental procedure for each process step was the following: - The feed was poured into the crystallizer at 70 °C. - The feed was then cooled down to the target temperature to obtain a crystal slurry. - The crystal slurry was pumped to the filter press using overpressure on the crystallizer. - The filter press was then squeezed to about 25 bar. - The liquid product was filtered through and a solid filter cake was obtained in the filter which is then collected. - Both the liquid and solid products are sent for Gas Chromatography analysis to determine the composition (the fatty acid composition was measured using gas chromatography, using the method ISO 12966-2:2017 and method ISO 12966-4:2015).PT-2125-WO-PCT

[0133] Table 4 shows the result of the first crystallization step at a temperature of 27.5 °C. Table 5 shows the result of the second crystallization step at a temperature of 8 °C, 12 °C and 15 °C. Table 6 shows the result of the stripping step at 42 °C, 43.5 °C and 45 °C. Table 4: Total branched and linear fatty acids for the feed and the 1stsolid product and 1stliquid product Temperature 27.5 °C Feed 1stsolid product 1stliquid producty p liquid product Temperature 8 °C 12 °C 15 °C nd nd nd nd nd ndid tPT-2125-WO-PCT Table 6: Total branched and linear fatty acids for the feed and the 3rdsolid product and 3rdliquid product Temperature 42 °C 43.5 °C 45 °C Feed 3rdsolid 3rdliquid 3rdsolid 3rdliquid 3rdsolid 3rd liquid

Claims

PT-2125-WO-PCT CLAIMS 1. A process for separating alkyl branched fatty acids from a fatty acid mixture comprising the steps of: a) providing a fatty acid mixture comprising alkyl branched fatty acids and linear fatty acids; b) subjecting the fatty acid mixture to a first crystallization step resulting in a first solid product and a first liquid product, wherein the first crystallization step occurs between 20 and 40 °C, preferably between 22 and 35 °C, more preferably between 25 and 30 °C; c) subjecting the first solid product and the first liquid product to a first separation step; d) subjecting the first liquid product to a second crystallization step resulting in a second solid product and a second liquid product, wherein the second crystallization step occurs between 5 and 20 °C, preferably between 8 and 18 °C, more preferably between 10 and 15 °C, and subjecting the first solid product to a stripping step resulting in a third solid product and a third liquid product, wherein the stripping step occurs between 35 and 55 °C, preferably between 38 and 52 °C, more preferably between 42 and 50 °C; e) subjecting the second solid product and the second liquid product to a second separation step, wherein the second liquid product comprises more than 80 wt.% of alkyl branched fatty acids relative to the total weight of the second liquid product, and subjecting the third solid product and the third liquid product to a third separation step, wherein the third solid product comprises less than 35 wt.%, preferably less than 34 wt.%, more preferably less than 30 wt.% of alkyl branched fatty acids relative to the total weight of the third solid product; and f) recycling of the second solid product and the third liquid product to the fatty acid mixture of step a).

2. Process according to claim 1, wherein the fatty acid mixture comprises - more than 50 wt.% of alkyl branched fatty acids, more preferably more than 60 wt.%, most preferably more than 65 wt.%, relative to the total weight of the fatty acid mixture, andPT-2125-WO-PCT - less than 40 wt.% of linear fatty acids, more preferably less than 30 wt.%, most preferably less than 20 wt.% relative to the total weight of the fatty acid mixture.

3. Process according to claim 1 or 2, wherein the fatty acid mixture provided in step a) has a temperature between 60 and 80 °C, preferably between 65 and 75 °C, more preferably between 68 and 72 °C.

4. Process according to any one of claims 1-3, wherein the first crystallization, second crystallization step and / or stripping step occurs in a crystallizer, preferably a solid layer crystallizer or a suspension crystallizer.

5. Process according to any one of claims 1-4, wherein the crystallizer is a suspension crystallizer being a stirred tank crystallizer or a tubular crystallizer, preferably a stirred tank crystalliser.

6. Process according to any one of claims 1-5, wherein the first, second and / or third separation step occurs with a filter press, by centrifugation or with a wash column, preferably with a filter press.

7. Process according to any one of claims 1-6, wherein the first liquid product comprises - between 70 and 95 wt.% of alkyl branched fatty acids, more preferably between 75 and 90 wt.%, most preferably between 78 and 85 wt.%, relative to the total weight of the first liquid product; and - between 5 and 30 wt.% of linear fatty acids, preferably between 10 and 25 wt.%, most preferably between 12 and 22 wt.%, relative to the total weight of the first liquid product.

8. Process according to any one of claims 1-7, wherein the first solid product comprises - between 10 and 45 wt.% of alkyl branched fatty acids, more preferably between 15 and 40 wt.%, most preferably between 20 and 35 wt.%, relative to the total weight of the first solid product; andPT-2125-WO-PCT - between 55 and 90 wt.% of linear fatty acids, preferably between 60 and 85 wt.%, most preferably between 65 and 80 wt.%, relative to the total weight of the first solid product.

9. Process according to any one of claims 1-8, wherein the second liquid product comprises - between 80 and 99 wt.% of alkyl branched fatty acids, more preferably between 85 and 95 wt.%, most preferably between 88 and 92 wt.%, relative to the total weight of the second liquid product; and - between 1 and 20 wt.% of linear fatty acids, preferably between 5 and 15 wt.%, most preferably between 8 and 12 wt.%, relative to the total weight of the second liquid product.

10. Process according to any one of claims 1-9, wherein the second solid product comprises - between 35 and 55 wt.% of alkyl branched fatty acids, more preferably between 40 and 50 wt.%, most preferably between 42 and 48 wt.%, relative to the total weight of the second solid product; and - between 45 and 65 wt.% of linear fatty acids, preferably between 50 and 60 wt.%, most preferably between 52 and 58 wt.%, relative to the total weight of the second solid product.

11. Process according to any one of claims 1-10, wherein the third liquid product comprises - between 35 and 65 wt.% of alkyl branched fatty acids, more preferably between 40 and 60 wt.%, most preferably between 45 and 55 wt.%, relative to the total weight of the third liquid product; and - between 35 and 65 wt.% of linear fatty acids, preferably between 40 and 60 wt.%, most preferably between 45 and 55 wt.%, relative to the total weight of the third liquid product.

12. Process according to any one of claims 1-11, wherein the third solid product comprises - between 5 and 35 wt.% of alkyl branched fatty acids, more preferably between 10 and 33 wt.%, most preferably between 15 and 30 wt.%, relative to the total weight of the third solid product; andPT-2125-WO-PCT - between 55 and 90 wt.% of linear fatty acids, preferably between 60 and 85 wt.%, most preferably between 65 and 80 wt.%, relative to the total weight of the third solid product.

13. Process according to any one of claims 1-12, wherein the alkyl branched fatty acids are C12-C24 alkyl branched fatty acids, more preferably C14-C22 alkyl branched fatty acids, even more preferably alkyl branched C16- C22 fatty acids; and wherein the linear fatty acids are C12-C24 linear fatty acids, preferably C14-C22 linear fatty acids, most preferably C16-C22 linear fatty acids.

14. Process according to any one of claims 1-13, wherein more than 50%, preferably more than 55%, even more preferably more than 60%, most preferably more than 65% of the second liquid product is recovered, relative to the total weight of the fatty acid mixture.

15. Process according to any one of claims 1-14 being a continuous process.

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