Fractional separation of crude tall oil

Abstract

The present invention relates to the fractionation of crude tall oil derived from sulfate process black liquor. In the process according to the invention, fractions are effectively separated from crude tall oil using at least two (two) strongly basic anion exchange resins.

Description

Technical Field

[0001] The present invention relates to the fractionation of crude tall oil, which is derived from Kraft liquor. In the method according to the present invention, at least two strong basic anion exchange resins are used to effectively separate fractions from the crude tall oil. Background Art

[0002] During the production of sulfate pulp, black liquor is formed and removed from the produced pulp. The removed black liquor contains soaps that need to be separated from the black liquor because the soaps contain valuable raw materials. Then, the water from the black liquor is evaporated, and the black liquor soap is skimmed off and acidified to prepare crude tall oil (CTO). Another reason for separating the soap from the black liquor is that the soap may cause problems during subsequent processing steps of the black liquor.

[0003] The separated soap contains extracts, water, lignin, inorganic compounds, fibers, and some black liquor. The fatty acids and rosin acids of crude tall oil (CTO) are in the form of sodium salts in the soap. The amount of each component in the soap depends on the raw materials and their seasonal variations, the pulping method used, and the method of separating the soap from the black liquor, i.e., the soap skimming process. CTO mainly consists of fatty acids (TOFA), rosin acids (TOR), and unsaponifiables.

[0004] Crude tall oil is a valuable raw material, and it is important to recover as much crude tall oil as possible from the soap. Crude tall oil can be used as a raw material for various chemicals and other products, such as biodiesel or detergents.

[0005] CTO can be separated from the soap by adding acid to the soap at a certain temperature. After the soap and the added acid are mixed, tall oil is formed, and then due to the density difference of the phases, it separates into three main phases; the CTO phase, the lignin phase, and the spent acid phase (also called brine). The lignin and the spent acid phase are waste in the production of CTO, and they need to be well separated from the CTO phase during the recovery of CTO.

[0006] The amount of acid required to separate the optimal amount of CTO from the soap depends on the quality of the soap, such as the CTO content, the water content, the fiber amount, the lignin content, and / or the black liquor content. Currently, the density of the soap and the pH and density of the spent acid are usually measured as a measure of the amount of acid and water that need to be added to separate the optimal amount of CTO from the soap. These measurements are carried out online, and then the required amounts of acid and water are adjusted, i.e., feedback control.

[0007] Traditionally, CTO has been fractionated into fractions such as head cut (low boiling point compounds), fatty acids, rosin acids, and pitch (distillation residue) using vacuum distillation. In addition, since the boiling points of fatty acids and rosin acids are similar, an intermediate fraction can be collected to prevent contamination of the fatty acid and rosin acid fractions. During the distillation of CTO at high temperature, the alcohol is esterified by the carboxylic acid, resulting in a lower yield of the free acid fraction and an increase in the lower value pitch fraction. In addition, thermal decomposition of the compounds can occur during high temperature distillation.

[0008] As described above, CTO can be used to produce several different products. Alternatively, CTO can first be separated into unsaponifiables and tall oil with high acid value. The tall oil with high acid value can be further separated into rosin acid and fatty acids. The unsaponifiable fraction contains i.a. phytosterols.

[0009] Phytosterols have several uses, including as food additives and precursors for steroids. Several methods for separating sterols from tall oil soap have been reported, such as extracting pure soap with various organic solvents.

[0010] Currently, phytosterols are commercially produced, for example, from tall oil pitch. Due to the ester formation during distillation, if the goal is to produce free phytosterols, the phytosterol esters must be hydrolyzed. This requires additional process steps.

[0011] There is a need for an easier and more efficient method for producing phytosterols from crude tall oil and preferably also producing tall oil with high acid value. SUMMARY OF THE INVENTION

[0012] It has surprisingly been found that the method according to the invention can be used to more efficiently separate CTO into a neutral fraction and a neutral depleted fraction. The neutral fraction mainly contains components that are generally described as unsaponifiables. The neutral depleted fraction mainly contains components such as sodium salts of fatty acids and rosin acids.

[0013] Accordingly, the present invention relates to a method for separating components from crude tall oil, comprising the steps of:

[0014] a) providing a mixture comprising crude tall oil and an alcohol selected from methanol, ethanol, and / or isopropanol,

[0015] b) contacting the mixture from step a) with a strongly basic anion exchange resin, and

[0016] c) collecting at least a first fraction and a second fraction, wherein each fraction contains at least one component, and

[0017] d) contacting the first fraction collected in step c) with a second strongly basic anion exchange resin, and

[0018] e) collecting a neutral fraction and a neutral depleted fraction.

[0019] The present invention also relates to the fractions collected in step c) of the method of the present invention. In particular, the present invention relates to a composition comprising sodium salts of fatty acids and rosin acids and a composition comprising phytosterols. After additional process steps, a composition comprising tall oil with a high acid value can be obtained. Description of the Drawings

[0020] Figure 1 : Schematic diagram of a method for separating components from crude tall oil. The figure shows providing a mixture (1) comprising crude tall oil and an alcohol, contacting the mixture (1) with a strongly basic anion exchange resin (2), collecting a first fraction (3) and a second fraction (7), contacting the first fraction (3) with a second strongly basic anion exchange resin (4), and collecting a neutral fraction (5) and a neutral depleted fraction (6). The neutral depleted fraction (6) can optionally be combined with the second fraction (7). Detailed Description

[0021] During the production of sulfate pulp, black liquor is formed and removed from the produced pulp. The removed black liquor contains soaps that need to be separated from the black liquor because the soaps contain valuable raw materials. Then the water from the black liquor is evaporated, and the black liquor soap is skimmed off and acidified to prepare crude tall oil. Thus, crude tall oil can be derived from the pulping of softwood, hardwood, or a mixture thereof.

[0022] The mixture (1) used in step a) preferably contains at least 1% by weight of an alcohol selected from methanol, ethanol, and / or isopropanol, based on the total weight of the mixture. The alcohol is a solvent in which tall oil is soluble and also enables the function of a strongly basic anion exchange resin. More preferably, the mixture used in step a) contains at least 5% by weight of an alcohol selected from methanol, ethanol, and / or isopropanol, such as at least 10% by weight of an alcohol selected from methanol, ethanol, and / or isopropanol or at least 15% by weight of an alcohol selected from methanol, ethanol, and / or isopropanol or at least 20% by weight of an alcohol selected from methanol, ethanol, and / or isopropanol or at least 25% by weight of an alcohol selected from methanol, ethanol, and / or isopropanol, based on the total weight of the mixture. Preferably, the mixture used in step a) contains less than 75% by weight of an alcohol selected from methanol, ethanol, and / or isopropanol, based on the total weight of the mixture. More preferably, the mixture used in step a) contains less than 60% by weight of an alcohol selected from methanol, ethanol, and / or isopropanol, such as less than 50% by weight of an alcohol selected from methanol, ethanol, and / or isopropanol, based on the total weight of the mixture. The mixture used in step a) may contain other components in addition to crude tall oil and an alcohol selected from methanol, ethanol, and / or isopropanol. However, based on the total weight of the mixture, the mixture used in step a) preferably contains at least 40% by weight of crude tall oil. More preferably, based on the total weight of the mixture, the mixture contains at least 50% by weight of crude tall oil, such as at least 60% by weight of crude tall oil or at least 70% by weight of crude tall oil, at least 80% by weight of crude tall oil or at least 90% by weight of crude tall oil or at least 95% by weight of crude tall oil. Preferably, the alcohol used in the mixture used in step a) is methanol.

[0023] In one embodiment, the mixture used in step a) is prepared by mixing an alcohol selected from methanol, ethanol, and / or isopropanol with crude tall oil. In one embodiment of the invention, before step b), the mixture of an alcohol selected from methanol, ethanol, and / or isopropanol and crude tall oil is contacted with a strong acid cation exchange resin. The benefit of performing this strong acid cation exchange step before step b) is that alkali metal salts can be removed from the mixture and the residual soap can be at least partially converted to a neutral form before step b), which results in higher yields and higher purities of the components in the first and second fractions.

[0024] The strongly basic anion exchange resin (2) used in step b) is preferably an anion exchange resin having quaternary ammonium groups incorporated into the polymer framework.

[0025] In step b), it is preferred to bring the mixture (1) of step a) into contact with a strongly basic anion exchange resin (2) in a column. In step b), the mixture of step a) is added to the strongly basic anion exchange resin. As it passes through the strongly basic anion exchange resin, the acidic components of the mixture attach to the strongly basic anion exchange resin, while the neutral components of the mixture flow out of the resin and are collected as a first fraction (3). The flow rate through the strongly basic anion exchange resin is preferably 4 to 15 bed volumes per hour, such as 5 to 10 bed volumes per hour or 5 to 8 bed volumes per hour. Based on the capacity of the strongly basic anion exchange resin, the amount of CTO loaded onto the resin is preferably 0.5 - 1 acid equivalent. The temperature used in step b) is preferably in the range of 10°C to 80°C, more preferably in the range of 20°C to 60°C, such as 30°C to 60°C, such as 40°C to 60°C or 30°C to 50°C.

[0026] During step c), the first fraction (3) is collected. After the mixture of step b), an additional alcohol selected from methanol, ethanol, and / or isopropanol (optionally mixed with water) is optionally added to the column to elute the remaining neutral components collected as the first fraction (3). The flow rate through the column is preferably 4 to 15 bed volumes per hour, such as 5 to 10 bed volumes per hour or 5 to 8 bed volumes per hour. Preferably, the additional alcohol added is methanol.

[0027] Subsequently, as part of step c), the acidic components that have attached to the strongly basic anion exchange resin are preferably released from the strongly basic anion exchange resin by adding a mixture containing sodium hydroxide and an alcohol selected from methanol, ethanol, and / or isopropanol. The concentration of sodium hydroxide in the mixture is preferably 0.05M - 6.0M. The mixture of sodium hydroxide and an alcohol selected from methanol, ethanol, and / or isopropanol optionally contains 0 wt% to 25 wt% of water, such as 0 - 10 wt% or 1 - 10 wt% water or 5 - 10 wt% water. Preferably, the alcohol is methanol.

[0028] When the acidic components that have attached to the strongly basic anion exchange resin are released from the strongly basic anion exchange resin, they are collected as a second fraction (7) that is depleted of neutral compounds.

[0029] After the second fraction has been collected, the strongly basic anion exchange resin is preferably regenerated using methods known in the art before repeating step b). Generally, the strongly basic anion exchange resin is regenerated while the acidic components are being released from the strongly basic anion exchange resin. When the acidic components have been released from the strongly basic anion exchange resin, the excess base can be removed from the strongly basic anion exchange resin by adding a pure alcohol selected from methanol, ethanol, and / or isopropanol. Preferably, the alcohol is methanol. When the second strongly basic anion exchange resin is regenerated in step e), the excess base can be collected and reused, thereby maximizing the use of the base.

[0030] The second strongly basic anion exchange resin (4) used in step d) is preferably an anion exchange resin having quaternary ammonium groups incorporated into the polymer framework.

[0031] In step d), the first fraction (3) collected in step c) is added to the second strongly basic anion exchange resin (4). In step d), it is preferred that the first fraction collected in step c) is brought into contact with the second strongly basic anion exchange resin in a column. When passing through the second strongly basic anion exchange resin, the remaining acidic components of the first fraction adhere to the strongly basic anion exchange resin, while the remaining neutral components of the mixture flow out of the resin and are collected as the neutral fraction (5), thereby maximizing the yield and purity of phytosterols and also increasing the purity of the second fraction as well as the neutral-depleted fraction. The flow rate through the second strongly basic anion exchange resin is preferably 4 to 15 bed volumes per hour, such as 5 to 10 bed volumes per hour or 5 to 8 bed volumes per hour. Based on the capacity of the second strongly basic anion exchange resin, the amount of the first fraction loaded onto the second resin is preferably 0.1 - 1 acid equivalent. The temperature used in step d) is preferably in the range of 10°C to 80°C, more preferably in the range of 20°C to 60°C, such as 30°C to 60°C, such as 40°C to 60°C or 30°C to 50°C.

[0032] In step e), the neutral fraction (5) is collected. After the mixture of step d), an additional alcohol selected from methanol, ethanol, and / or isopropanol (optionally mixed with water) is optionally added to the column to elute the remaining neutral components collected as the neutral fraction (5). The flow rate through the column is preferably 4 to 15 bed volumes per hour, such as 5 to 10 bed volumes per hour or 5 to 8 bed volumes per hour. Preferably, the additional alcohol added is methanol.

[0033] As part of step e), it is preferred to release the acidic components that have adhered to the strongly basic anion exchange resin from the strongly basic anion exchange resin by adding a mixture comprising sodium hydroxide and an alcohol selected from methanol, ethanol, and / or isopropanol. The concentration of sodium hydroxide in the mixture is preferably 0.05 M - 6.0 M. The mixture of sodium hydroxide and an alcohol selected from methanol, ethanol, and / or isopropanol optionally contains 0 wt% to 25 wt% of water, such as 0 - 10 wt% or 1 - 10 wt% water or 5 - 10 wt% water. Preferably, the alcohol is methanol.

[0034] When the acidic components that have adhered to the second strongly basic anion exchange resin are released from the strongly basic anion exchange resin, they are collected as the neutral-depleted fraction (6), which may optionally be combined with fraction (7).

[0035] After step e), the second strongly basic anion exchange resin is preferably regenerated in the same manner as the first strongly basic anion exchange resin.

[0036] Thus, the method according to the invention comprises the following steps:

[0037] - Providing a mixture (1) comprising crude tall oil and an alcohol selected from methanol, ethanol and / or isopropanol;

[0038] - Optionally contacting the mixture comprising crude tall oil and an alcohol selected from methanol, ethanol and / or isopropanol with a strong acid cation exchange resin;

[0039] - Contacting the mixture comprising crude tall oil and an alcohol selected from methanol, ethanol and / or isopropanol with a strongly basic anion exchange resin (2); and

[0040] o Collecting at least a first fraction (3) comprising at least one component;

[0041] o Releasing the acidic components that have adhered to the strongly basic anion exchange resin from the strongly basic anion exchange resin, preferably by adding a mixture comprising sodium hydroxide and an alcohol selected from methanol, ethanol and / or isopropanol; and

[0042] o Collecting a second fraction (7) comprising at least one component and depleted in neutral compounds

[0043] - Contacting the first fraction (3) with a second strongly basic anion exchange resin (4), and

[0044] o Collecting a neutral fraction (5) and

[0045] o Releasing the acidic components that have adhered to the second strongly basic anion exchange resin from the second strongly basic anion exchange resin, preferably by adding a mixture comprising sodium hydroxide and an alcohol selected from methanol, ethanol and / or isopropanol, and

[0046] o Collecting a neutral depleted fraction (6), which may optionally be combined with the second fraction (7).

[0047] The first fraction (3) is the first fraction exiting the first strongly basic ion exchange resin. The first fraction is partially acid-depleted. The first fraction contains components that are generally described as unsaponifiables, as well as fatty acids and rosin acids and solvents. The first fraction also contains phytosterols.

[0048] Contact the first fraction with a second strongly basic anion exchange resin (4).

[0049] After contacting the first fraction (3) with the second strongly basic anion exchange resin (4), collect the neutral fraction (5) and the neutral depleted fraction (6).

[0050] From the neutral fraction (5), the phytosterols are preferably separated from other neutral compounds. It has surprisingly been found that the phytosterols can crystallize spontaneously in the neutral fraction. Advantageously, the phytosterols obtained are not esterified, which is usually the case with prior art methods. If this spontaneous crystallization cannot be achieved, methods known in the art can generally be used to separate the phytosterols from other neutral compounds, for example by crystallization, such as evaporation crystallization, static crystallization or cooling crystallization. The alcohol selected from methanol, ethanol and / or isopropanol can be distilled off or alternatively be part of a precipitation / crystallization solvent system. The alcohol selected from methanol, ethanol and / or isopropanol is preferably recycled in the process according to the invention. The precipitate / crystals produced can be further purified by vacuum distillation or recrystallization or a combination thereof, optionally followed by washing and drying.

[0051] The yield and purity of the phytosterols are maximized by contacting the first fraction (3) with a second strongly basic anion exchange resin.

[0052] One aspect of the invention is a composition comprising phytosterols, wherein the composition comprises less than 0.5 wt-% of tall oil and wherein the composition comprises less than 1 wt-% of esterified phytosterols.

[0053] The neutral depleted fraction (6) withdrawn is a soap fraction. The neutral depleted fraction (6) can be combined with the second fraction (7) withdrawn from the first strongly basic ion exchange resin (2). The neutral depleted fraction (6), optionally combined with the second fraction (7), contains components such as sodium salts of fatty acids and rosin acids. It has surprisingly been found that the acid salts can crystallize / precipitate spontaneously in the neutral depleted fraction as a white precipitate / crystals. It has surprisingly been found that the color remains in the liquid phase. The crystallized / precipitated material can optionally be purified by subsequent recrystallization.

[0054] The neutral depleted fraction (6), optionally combined with the second fraction (7), can also be dried by evaporating the alcohol selected from methanol, ethanol and / or isopropanol using methods known in the art to produce a dry mixture of fatty acid and rosin acid salts. The dry material can also be washed or repulped, for example washed with water or repulped in water, to remove excess sodium hydroxide from the dry material. Preferably, washing is carried out with water, wherein the temperature of the water is preferably in the range of 20 °C to 80 °C, such as 40 °C to 60 °C. Preferably, when the wash liquid is removed from the slurry, the slurry has a temperature in the range of 15 °C to 25 °C. The sodium hydroxide removed can be recycled in the process.

[0055] Mixtures of fatty acids and rosinates can be further fractionated, for example, using precipitation / crystallization methods or converted into high-quality tall oil using methods known in the art. The high-quality tall oil can be further fractionated into tall oil fatty acids and tall oil rosin acids using a chromatographic system or by standard vacuum distillation. In one embodiment, the high acid value tall oil is first converted into a mixture of fatty acid methyl esters and rosin acids by esterification. Subsequently, the fatty acid methyl esters and rosin acids can be separated from each other using methods known in the art.

[0056] One aspect of the invention is a composition comprising tall oil having an acid value of at least 175, which composition comprises less than 0.5 wt-% phytosterols, based on the total weight of the composition. The composition preferably has a Gardner Color Number of less than 14, more preferably less than 9, as determined according to ASTM D1544-04.

[0057] The acid value of tall oil can be determined using methods known in the art. One way to evaluate the quality of tall oil is to describe its acid value, which is the amount (in milligrams) of potassium hydroxide required to neutralize 1 g of CTO. As used herein, the term "high acid value tall oil" refers to tall oil having an acid value of at least 175, such as at least 180 or at least 185 or at least 188.

[0058] The term "phytosterol" is intended to mean sterols derived from plants and encompasses all phytosterols and their saturated forms of phytosterols (i.e., phytostanols). Phytosterols belong to one of the following three classes: 4-demethylsterols (lacking a methyl group); 4-monomethylsterols (one methyl group); and 4,4-dimethylsterols (two methyl groups), and include but are not limited to sitosterols (e.g., [α] and [β] sitosterols), campesterol, stigmasterol, taraxasterol, and brassicasterol. The term "phytostanol" is intended to mean saturated phytosterols and encompasses but is not limited to sitostanol (e.g., [α] and [β] sitostanol), campestanol, stigmasterol, clionastanol, and brassicastanol. The phytosterols isolated as described herein can be quantified by any method known in the art.

[0059] Phytosterol crystallization can be carried out using methods known in the art, including cooling, concentration by removing some solvent by distillation, evaporation to dryness, and then introducing a solvent or solvent mixture in which the phytosterols dissolve only at elevated temperatures, followed by cooling or by inoculating with phytosterol crystals or by adding an anti-solvent. Precipitation or crystallization can occur after a step of evaporating (e.g., distilling off) some or all of the solvent. Alternatively, an additional solvent, such as an anti-solvent, can be added to promote precipitation or crystallization of the phytosterols, optionally in combination with inoculation.

[0060] The method according to the invention can be carried out in a batch process. However, by using more than one strongly basic anion exchange column, the method can be run continuously by switching the flow of the mixture of step a) from the first strongly basic anion exchange column to the second strongly basic anion exchange column. In such a continuous process, the first fraction is thus withdrawn from the first strongly basic anion exchange column while the mixture of step a) flows through the first strongly basic anion exchange column. When the flow of the mixture of step a) is switched to flow through the second strongly basic anion exchange column, the second fraction can be withdrawn from the first strongly basic anion exchange column. This enables the method steps a) to c) to be carried out continuously. In the same way, steps d) and e) can be carried out continuously.

[0061] Preferably, the crude tall oil is pretreated before the strongly basic anion exchange. The pretreatment preferably includes removing fibers and any other components that may cause clogging of the strongly basic anion exchange column system.

[0062] Examples

[0063] Materials

[0064] A small-scale preparation column of 1X (ion exchange) resin was constructed using standard Luer fittings from a Biotage ISOLUTE single frit reservoir. A syringe pump (Harvard Apparatus 11S) was used to pump the solutions.

[0065] Preparation of solutions

[0066] A 1.75 M sodium hydroxide solution for activating the ion exchange resin was prepared by dissolving solid sodium hydroxide (70 g / L) in a 4 / 1 mixture of methanol and deionized water at room temperature.

[0067] A methanol solution of 0.67 M sodium hydroxide was prepared by dissolving solid sodium hydroxide (26.8 g / L) in methanol at room temperature.

[0068] A methanol solution of 75 wt.% CTO was prepared by mixing crude tall oil (217 g) with methanol (72 g). The resulting solution (289 g) was used for each separation cycle.

[0069] A 1.5 M sodium hydroxide methanol solution was prepared by dissolving sodium hydroxide (60 g) in methanol in a 1 L volumetric flask at room temperature.

[0070] 0.67 M sodium hydroxide in methanol was prepared by diluting an aqueous sodium hydroxide solution (53.6 g, 50 wt% aq.) with methanol in a 1 L volumetric flask at room temperature.

[0071] A 50 wt.% CTO solution in methanol was prepared by dissolving crude tall oil (100 g) in methanol (100 g). The resulting solution was dark-colored.

[0072] Preparation of strongly acidic cation exchange resin (SAC)

[0073] Purolite PPC100H (22 mL) was loaded into a column (Ø 22 mm, length 65 mm) between 10 μm polyethylene filter disks and swollen overnight in methanol. The methanol was drained, and fresh methanol (50 mL) was pumped through the resin bed (upflow 45 mL / h). Sulfuric acid (70 mL, 4 vol% in water) was pumped through the resin bed (100 mL / h upflow), and then deionized water (150 mL, 45 mL / h) was pumped. The SAC-resin was then rinsed with methanol (50 mL, 45 mL / h).

[0074] Demineralization of 75 wt.% CTO in methanol using SAC-resin

[0075] The CTO-solution (200 ml, 182 g, 75 wt.% in MeOH) was pumped through the SAC-resin bed (upflow 20 ml / h) and the demineralized product was collected. ICP was used to analyze the metal content of the samples before and after demineralization. The data are the average of three separate samples

[0076]

[0077] Small-scale separation experiment:

[0078] Preparation of strongly basic anion exchange resin (SBA)

[0079] Purolite A500OHPlus (12.4 g / 20 mL) was loaded into a column (Ø22mm, length 65 mm) between 10 μm polyethylene filter disks and swollen overnight in methanol. The SBA-resin was drained, and sodium hydroxide (20 mL, 1.75M, in a 4 / 1 mixture of methanol and water) was pumped through the resin bed (upflow 40 mL / h). The SBA-resin was then rinsed with methanol (110 mL) until the conductivity < 10 μS / cm.

[0080] Separation of sterols using 50 or 75 wt.% CTO in methanol

[0081] Add the CTO-solution (10 mL, 8.74 g, 50 wt.% in MeOH, or 6.66 mL, 6.05 g, 75 wt.% in MeOH) to the SBA-resin (upflow 10 - 40 mL / h), followed by addition of methanol (50 mL, 40 mL / h). Crystallization of the white solid occurred in the early fractions (0.4 - 1.0 bed volumes) consisting mainly of sterols. Cooling the early fractions to 4 °C gave a greater amount of crystalline material.

[0082] Separation of fatty acids and rosinates and regeneration of the IX-resin

[0083] Add a methanol solution of sodium hydroxide (1.5 M, 40 mL) to the SBA-resin, then add methanol (120 mL, flow rate 40 mL / h) until the conductivity < 10 μS / cm. At ambient temperature, soap precipitation as a white solid occurred in the early fractions (0.4 - 1.4 bed volumes). Cooling to 4 °C caused a large precipitation of the white material.

[0084] Large-scale separation experiments:

[0085] Preparation of strongly basic anion exchange resin (SBA)

[0086] Load the Purolite A500OHPlus resin (620 g) into a jacketed stainless-steel column (ID 50 mm, length 500 mm, volume 1 L) between 10 μm polyethylene filter discs and seal both ends of the column with end caps having inlets and outlets connected to Teflon tubes for injection and collection. Add demineralized water from the top and allow the resin to swell overnight. Drain the water and pump sodium hydroxide (2 L, 1.5 M in water) through the resin bed (downflow 2 L / h). Then rinse the IX-resin first with demineralized water (4 L) and then with methanol (1 L) until the conductivity < 10 μS / cm.

[0087] First column:

[0088] Separation of the first fraction (3) using 75 wt.% CTO in methanol

[0089] Heat the resin column to 50 °C using a hot water circulation bath through the heating jacket of the column and maintain the temperature throughout the separation.

[0090] Add the CTO-solution (1,289 g, 75 wt.% in MeOH) to the IX-resin column (133 mL / h, 8 BV / h). Elute the neutral compounds with methanol (1 L, 133 mL / h, 8 BV / h) and collect as the first fraction (3). Keep the collected fraction at 50 °C to prevent precipitation.

[0091] Separate the second fraction (7) and regenerate the IX-resin

[0092] Elute the acidic compounds from the IX-resin column using a solution of sodium hydroxide in methanol (0.67 M, 1.0 L, 133 mL / min, 8 BV / h) and collect as the second fraction (7). Then regenerate the IX-resin using a solution of sodium hydroxide in methanol (0.67 M, 1.0 L, 133 mL / min, 8 BV / h), and collect the effluent and use it as the eluent for the acidic compounds in the second column below.

[0093] The second fraction (7) may optionally be combined with the neutral depleted fraction (6) described below. Evaporate the combined saponified fraction to dryness under reduced pressure and collect the evaporated methanol for optional solvent recovery.

[0094] Using procedures known in the literature, the separated and dried sodium soap can be directly converted to a neutral depleted tall oil with a high acid value using concentrated H2SO4 and water, yielding a brown oily substance with an increased acid value.

[0095] Conditioning of the IX-resin column

[0096] After eluting and regenerating the resin column with a methanol solution of sodium hydroxide, rinse the column with methanol (1.5 L, 133 mL / min, 8 BV / h). Collect the methanol for optional solvent recovery and now condition the IX-resin column for a new separation cycle.

[0097] Second column:

[0098] Separation of the neutral fraction (5)

[0099] Heat the second resin column to 50 °C using a hot water circulating bath through the heating jacket of the column and maintain the temperature throughout the separation.

[0100] Add the first fraction (3) collected from the first column to the resin column (133 mL / min, 8 BV / h) at 50 °C. Elute the neutral compounds with methanol (1 L, 133 mL / h, 8 BV / h) and collect as the neutral fraction (5). Cool the neutral fraction to 4 °C, precipitate the solid material and separate by filtration. Wash the filter cake with cold methanol (50 mL) and dry under reduced pressure to obtain crude phytosterols as a light yellow solid.

[0101] Separation of the neutral depleted fraction (6) and regeneration of the IX-resin

[0102] The acidic compounds are eluted from the IX-resin column using the regenerated effluent of the first column, which is a solution of sodium hydroxide in methanol (<0.67 M, 1.0 L, 133 mL / min, 8 BV / h) with some residual soap from the first column, and collected as the neutral depleted fraction (6). The IX-resin is then regenerated using a solution of sodium hydroxide in methanol (0.67 M, 1.0 L, 133 mL / min, 8 BV / h), and the effluent is collected and can be used as the eluent for the acidic compounds in the first column during the next cycle. The neutral depleted fraction (6) can be combined with the second fraction (7) described above or, optionally, processed separately as described for the second fraction to obtain a neutral depleted tall oil with a high acid value.

[0103] Conditioning of the IX-resin column

[0104] After eluting and regenerating the resin column with a methanol solution of sodium hydroxide, the column is rinsed with methanol (1.5 L, 133 mL / min, 8 BV / h). The methanol is collected for optional solvent recovery, and the IX-resin column is now conditioned for a new separation cycle.

[0105] Analytical methods

[0106] According to known procedures, the identity and purity of individual components or groups of components are determined using GC / FID after silylation with BSTFA (N,O-bis(trimethylsilyl)trifluoroacetamide) in pyridine or using 31 P-NMR after derivatization with 2-chloro-4,4,5,5-tetramethyl-1,3,2-dioxaphospholane in deuterated chloroform / pyridine.

[0107] In view of the foregoing detailed description of the invention, other modifications and variations will be apparent to those skilled in the art. However, it is apparent that such other modifications and variations can be effected without departing from the spirit and scope of the invention.

Claims

1. A method for separating components from crude tall oil, comprising the following steps a) providing a mixture comprising crude tall oil and an alcohol selected from methanol, ethanol, and / or isopropanol, b) contacting the mixture from step a) with a strongly basic anion exchange resin, and c) collecting at least a first fraction and a second fraction, wherein each fraction comprises at least one component, and d) contacting the first fraction collected in step c) with a second strongly basic anion exchange resin, and e) collecting a neutral fraction and a neutral-depleted fraction.

2. The method according to claim 1, wherein one of the fractions is a fraction mainly comprising unsaponifiables.

3. The method according to claim 1 or 2, wherein one of the fractions is a fraction mainly comprising sodium salts of fatty acids and rosin acids.

4. The method according to claims 1-3, wherein the alcohol used in step a) is methanol.

5. The method according to any one of claims 1 to 4, wherein phytosterols are separated from the neutral fraction.

6. The method according to any one of claims 1-5, wherein step b) is carried out at a temperature of 30°C to 60°C.

7. The method according to claim 4, wherein based on the total weight of the mixture in step a), the amount of methanol in the mixture in step a) is at least 10% by weight.

8. The method according to any one of claims 1-2 or 4-7, wherein phytosterols spontaneously crystallize in the neutral fraction.

9. The method according to claim 8, wherein the spontaneously crystallized phytosterols mainly consist of β-sitosterol.

10. The method according to any one of claims 1 or 3-7, wherein tall oil having an acid value of at least 175 is produced from the neutral-depleted fraction.

11. A fraction separated and collected by the method according to any one of claims 1-10.

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