JP5238147B2 - Tall fatty acid ester, method for producing the same, and use thereof - Google Patents

Description

  The present invention relates to a tall fatty acid ester that can be used for biodiesel fuel and the like and a method for producing the same, and further relates to a biodiesel fuel using the tall fatty acid ester.

  In recent years, as awareness of global environmental conservation has increased, it is particularly necessary to implement measures to prevent global warming. Specifically, at the Kyoto Conference on Global Warming Prevention held in 1997, Japan has made an international commitment to reduce high-carbon dioxide emissions by 6% compared to the 1990 level. To achieve this, legislation has been enacted to further promote energy conservation and promote the development and use of new energy.

  Plant-derived biomass is an energy resource defined by the New Energy Law based on the concept of carbon neutral, and fatty acid methyl esters produced from vegetable oils and fats are being put into practical use as biodiesel fuel. For example, for the effective use of resources, the use of fatty acid methyl esters obtained by reacting fats and oils mainly composed of fatty acid glycerin esters with methanol in the presence of a catalyst has been studied. Yes. When biodiesel fuel is used as the fuel oil, the carbon dioxide emission reduction effect, the particulate (PM) / black smoke reduction effect, the sulfur oxide reduction effect, etc. are expected as advantages.

  Conventionally, it is known that a fatty acid ester is obtained by a direct esterification reaction between a free fatty acid and a lower alcohol (see Non-Patent Document 1). Such esterification reaction is a reversible reaction due to hydrolysis by the water produced, and in order to shift the chemical equilibrium to the production system side, the amount of alcohol used as a raw material is excessive, It is necessary to devise such as efficiently removing the product from the reaction system. In the esterification reaction between a free fatty acid and a lower alcohol, an acid or an alkali is generally used as a reaction catalyst. In order to simplify the separation step after the reaction, an ion exchange resin or a heteropolyacid-supported silica gel is used. A solid acid catalyst such as, or an enzyme (lipase) may also be used.

  However, when producing a fatty acid ester from a free fatty acid and a lower alcohol, it is difficult to complete the esterification reaction 100% under general conditions. For example, even if the reaction catalyst as described above is used and the generated water is discharged from the reaction system, a long reaction time is required to complete the reaction 100%. Furthermore, as a method for purifying the resulting ester, a method of removing unreacted fatty acids by washing with an aqueous alkaline solution is known, but in this case, alkaline waste water is generated, and the purification process requires a large amount. There was a problem that labor was required. In addition, the reaction catalyst is often in a uniform state in the reaction solution, and there is a problem that a complicated process for separation is required. All of these problems cause a rise in the cost of fatty acid esters. For practical use of biodiesel fuel, it is indispensable to realize low cost in order to ensure general quality as well as to ensure quality.

  By the way, crude tall oil generated in the kraft pulping process includes fatty acids produced by hydrolyzing wood fats and oils in the pulp cooking process, rosin acid present in the form of free acid in wood, and various types of oils. Contains sexual substances. These tall oil components are separated by continuous rectification operation, and rosin (pine resin) and tall fatty acid are produced. Therefore, tall fatty acids are cheaper than general fatty acids obtained by hydrolysis of natural fats and oils (vegetable fats, animal fats, fish oils, etc.) and can be said to be useful as raw materials for fatty acid esters used in biodiesel fuels. .

However, since kraft process pulping uses sodium sulfide during cooking, plant components and sulfur react to produce organic sulfur compounds. This organic sulfur compound is not completely separated by rectification of crude tall oil, and as a result, the sulfur content usually remains in the order of several hundred ppm in tall fatty acids. When subjected to such a sulfur concentration in biodiesel fuels still contains sulfur compounds, will generate sulfur oxides (SO _X) by combustion. Therefore, it has been difficult to use tall fatty acids as raw materials for fatty acid esters used in biodiesel fuels.

  Further, tall fatty acids usually contain about 1 to 5% by mass of rosin acid in the composition. Since the carboxylic acid group of this rosin acid has a secondary structure, the reactivity is low, and when esterifying a tall fatty acid and a lower alcohol, most of them remain unreacted, and the acid value of the resulting ester is reduced. This is the cause of further increase. If it is used for fuel with a high acid value (ie, with many carboxylic acid groups remaining), it will cause undesirable phenomena such as corrosion of combustion equipment. It was impossible to use as a raw material for the fatty acid ester used. In addition, tall fatty acids usually contain about 1 to 10% by mass of a neutral substance such as steroid, diterpene, triterpene, wax alcohol, prenol, polyphenol, stilbene in addition to rosin acid.

In general, as a method for purifying fats and oils and fatty acid esters, a method for purifying fats and oils with clay (see Non-patent Document 2), a method for adsorbing and purifying fatty acid esters with clay, alumina, silica gel, activated carbon, and the like (Patent Documents 1 and 2). For example). However, no examples of applying these purification methods to toluic acid esters have been reported so far.
JP-A-6-65591 JP 7-233121 A "New Edition Fatty Acid Chemistry" p161, Koshobo (1981) “New Edition Fatty Acid Chemistry” p13, Koshobo (1981)

  An object of the present invention is to provide a tall fatty acid ester that has characteristics suitable for biodiesel fuel with a low acid value and low sulfur content and is inexpensive, and the tall fatty acid ester can be easily operated without using a special apparatus. The manufacturing method to manufacture and the biodiesel fuel using this tall fatty acid ester are provided.

  As a result of intensive studies to solve the above problems, the present inventors have a possibility of being widely used as a biodiesel fuel if relatively inexpensive tall fatty acids and lower alcohols are used as raw materials for fatty acid esters. I thought that I could achieve the low cost. However, since the tall fatty acid ester made from tall fatty acid has insufficient quality (specifically, acid value and sulfur content) as a biodiesel fuel, a method for improving this without increasing the cost. It was investigated. Impurities consisting of unreacted tall fatty acids, rosin acids, lower alcohols, neutral substances, etc. (especially rosin acids and sulfur components that increase the acid value) from the reaction products obtained by esterification of tall fatty acids and lower alcohols In order to efficiently remove the impurities, etc. without cost, there are various purification methods utilizing the difference in polarity between the tall fatty acid ester and the impurities described above, and adsorbing these impurities etc. on an inorganic adsorbent. The present invention was completed by finding the most effective method.

That is, the present invention has the following configuration.
(1) A tall fatty acid ester obtained from tall fatty acid and a lower alcohol as raw materials, having an acid value of less than 0.5 mg KOH / g and a sulfur content of 50 ppm by mass or less.
(2) A tall fatty acid ester reaction solution is obtained by esterification using tall fatty acid and lower alcohol as raw materials, and the reaction solution is passed through an adsorption column filled with an inorganic adsorbent. Ester production method.
(3) The said tall fatty acid ester reaction liquid is made to flow at a rate of 100 parts by mass or less with respect to 100 parts by mass of the inorganic adsorbent and at an elution rate of 0.01 to 1.00 mL / cm ² · min. (2) The manufacturing method of the tall fatty acid ester as described.
(4) A method for producing a tall fatty acid ester, comprising using a tall fatty acid and a lower alcohol as raw materials to obtain a tall fatty acid ester reaction liquid by an esterification reaction, adding an inorganic adsorbent to the reaction liquid and stirring the reaction liquid.
(5) The method for producing tall fatty acid ester according to (4), wherein the inorganic adsorbent is added at a ratio such that the tall fatty acid ester reaction solution is 100 parts by mass or less with respect to 100 parts by mass of the inorganic adsorbent.
(6) The said tall oil fatty acid used as a raw material is a manufacturing method of the tall fatty acid ester in any one of said (2)-(5) which contains 1-5 mass% rosin acid.
(7) The method for producing a tall fatty acid ester according to any one of (2) to (6), wherein the lower alcohol used as a raw material is an alkyl alcohol having 1 to 4 carbon atoms.
(8) The inorganic fatty adsorbent according to any one of (2) to (7), wherein the inorganic adsorbent is at least one selected from the group consisting of activated carbon, zeolite, activated alumina, activated clay, and silica gel. Production method.
(9) A biodiesel fuel comprising the tall fatty acid ester according to (1).

  According to the present invention, a tall fatty acid ester having characteristics suitable for biodiesel fuel having a low acid value and low sulfur content and being inexpensive can be produced by a simple operation without using a special apparatus. There is an effect that. In addition, the biodiesel fuel of the present invention can achieve low cost to the extent that it can be widely used, and has characteristics suitable for biodiesel fuel with low acid value and low sulfur content.

Hereinafter, an embodiment of a tall fatty acid ester, a method for producing a tall fatty acid ester, and a biodiesel fuel according to the present invention will be described in detail.
The tall fatty acid ester of the present invention is obtained using a tall fatty acid and a lower alcohol as raw materials. Specifically, it can be obtained by the method for producing the tall fatty acid ester of the present invention described later. However, the tall fatty acid ester of the present invention is not limited to those obtained by the production method of the present invention described later.

  The tall fatty acid ester of the present invention has an acid value of less than 0.5 mg KOH / g and a sulfur content of 50 mass ppm or less. The sulfur content is preferably 40 ppm by mass or less, and more preferably 10 ppm by mass or less. If the acid value is 0.5 mgKOH / g or more, it will cause corrosion of combustion equipment over a long period of use. On the other hand, if the sulfur content exceeds 50 mass ppm, the JIS standard value of light oil will be exceeded. In addition, the acid value and sulfur content in this invention are measured by the method mentioned later in an Example.

  The tall fatty acid in the present invention is obtained as a fraction when crude tall oil is subjected to rectification. Tall fatty acids usually have an acid value (neutralization value) of 180 to 195 mg KOH / g, and the composition is mainly composed of aliphatic carboxylic acids (oleic acid, linoleic acid, etc.), and some rosin acids and neutrals. Ingredients included. In particular, in the present invention, it is preferable to use a tall fatty acid containing 1 to 5% by mass of rosin acid as a raw material. This is because, in this case, the acid value usually increases, but in the present invention, the effect that the acid value within the above range can be maintained becomes significant. Only one type of tall fatty acid may be used, or two or more types may be used. In addition, the field | area which isolate | separates the fatty acid and rosin acid contained in crude tall oil by vacuum distillation, and utilizes each as an industrial raw material is called naval store.

Although there is no restriction | limiting in particular as a lower alcohol in this invention, For example, C1-C4 alkyl alcohols, such as methanol, ethanol, propanol, butanol, are mentioned preferably at the point of the fuel characteristic of the obtained tall fatty acid ester. Only one type of lower alcohol may be used, or two or more types may be used.
In particular, the alcohol having 1 to 3 carbon atoms of the lower alcohol is mixed with water in a wide proportion, so that it is difficult to separate the reaction product water, and since the boiling point is low, the reaction temperature becomes low and the reaction rate becomes insufficient. . Increasing the number of carbon atoms is advantageous in terms of separation of produced water and reaction rate, but also increases the price of itself. For these reasons, the carbon number of the lower alcohol is preferably 4 (butanol) when performing the esterification reaction in a batch reaction at normal pressure.

  The proportion of tall fatty acid and lower alcohol used as raw materials in the present invention is not particularly limited, but it is desirable that the lower alcohol be excessive. Specifically, tall fatty acid: lower alcohol = 1: 1 to 1. A range of 5 (molar ratio) is preferred. When the proportion of the lower alcohol is lower than the above range, the achievement rate of the reaction may be insufficient. On the other hand, when the proportion of the lower alcohol is higher than the above range, the amount of alcohol distilling during the reaction increases. As a result, even if alcohol is recovered and reused, it is economically disadvantageous, and the effect of the present invention that low costs can be realized by using tall fatty acid as a raw material tends to be impaired.

In the method for producing a tall fatty acid ester of the present invention, a tall fatty acid ester reaction solution is obtained by an esterification reaction using tall fatty acids and lower alcohols as raw materials.
The tall fatty acid and lower alcohol used in the production method of the present invention are as described above. Further, the use ratio of tall fatty acid and lower alcohol is as described above.

  The esterification reaction is carried out by first mixing tall fatty acid, lower alcohol and, if necessary, a solvent (for example, toluene, xylene, etc.) at a predetermined ratio, adding an appropriate reaction catalyst and heating.

  The catalyst used in the esterification reaction is not particularly limited, and may be appropriately selected from known catalysts such as acids and alkalis, and further solid catalysts and enzymes (lipases). In the present invention, paratoluenesulfonic acid is preferred when the esterification reaction is carried out in a batch system described later, particularly from the viewpoint of easy reaction activity and separation after the reaction. When carried out by the formula, sulfated zirconia is preferred.

  As a type of the reaction apparatus for the esterification reaction, a batch type (batch type) or a continuous type using a flow type reactor can be adopted. When the esterification reaction is carried out batchwise, the higher the reaction temperature, the faster the reaction rate and the better. However, in the batch operation at normal pressure, the reaction temperature is limited by the boiling point of the refluxing lower alcohol or solvent. On the other hand, for the continuous esterification reaction, a continuous reaction under pressure is usually selected when producing a known fatty acid methyl ester as a biodiesel fuel. In this case, a special dehydrator is required to efficiently discharge the produced water out of the reaction system, which is disadvantageous in terms of equipment cost burden. However, in the present invention, by performing a two-stage reaction using a continuous reactor filled with a solid catalyst, the residual acid value of the tall fatty acid ester can be within a purifiable range in the next step.

In the method for producing a tall fatty acid ester of the present invention, the tall fatty acid ester reaction solution obtained by the esterification reaction is subjected to (I) a treatment for passing through an adsorption column filled with an inorganic adsorbent. Or (II) An inorganic adsorbent is added and stirred. By this (I) or (II), polar substances (unreacted fatty acid / resin acid, neutral component and reaction catalyst) contained in the tall fatty acid ester reaction liquid are adsorbed and removed by the inorganic adsorbent. Regardless of (I) or (II), since the difference in polarity between the tall fatty acid ester and the polar substance is utilized, the tall fatty acid ester is produced by a simple operation without using a special apparatus. can do.
When performing (I) or (II), it is preferable to remove the remaining lower alcohol by distillation operation or the like in advance after the ester reaction. This is because if the lower alcohol remains, the polar substance in the ester reaction solution is prevented from being adsorbed by the inorganic adsorbent.

  The inorganic adsorbent is not particularly limited as long as it is an inorganic adsorbent capable of adsorbing a polar substance, but at least selected from the group consisting of activated carbon, zeolite, activated alumina, activated clay and silica gel. One type is preferable in terms of adsorptivity to polar substances. Among these, porous silica gel is particularly preferable in terms of separation performance and yield with respect to polar substances. The physical properties of the silica gel preferably used include, for example, a pore diameter of 5 to 10 nm, a pore volume of 0.1 to 2.0 mL / g, a specific surface area of 300 to 600 m <2> / g, and a particle size of 45 to 75 [mu] m of 65 to 85%. As described above, the 75 μm residue is about 1 to 10% or less. As a specific example of the porous silica gel having such physical properties, for example, trade name “Wakogel C300” manufactured by Wako Pure Chemical Industries, Ltd. may be mentioned.

In the above (I), the tall fatty acid ester reaction liquid is added at a rate of 100 parts by mass or less with respect to 100 parts by mass of the inorganic adsorbent and at an elution rate of 0.01 to 1.00 mL / cm ² · min. It is preferable to let the liquid pass. Thereby, the polar substance contained in the tall fatty acid ester reaction liquid can be efficiently adsorbed to the inorganic adsorbent. When the amount of the tall fatty acid ester reaction solution exceeds 100 parts by mass with respect to 100 parts by mass of the inorganic adsorbent, the total amount of the polar substance may not be adsorbed by the inorganic adsorbent. In addition, when the elution rate is slower than 0.01 mL / cm ² · min, the working efficiency is lowered. On the other hand, when the elution rate is faster than 1.00 mL / cm ² · min, the polar substance is hardly absorbed by the inorganic adsorbent. Therefore, it is not preferable.

  In the above (I), if necessary, a non-polar solvent (for example, a saturated hydrocarbon solvent such as hexane or heptane) may be mixed with the tall fatty acid ester reaction solution and passed as a mixed solution. Thereby, the effect of promoting the separation and removal of polar substances can be expected.

  In (I) above, after a tall fatty acid ester reaction solution is passed through an adsorption column filled with an inorganic adsorbent, a predetermined amount of a nonpolar solvent (for example, the same as described above) is further passed. Is preferred. Thereby, the tall fatty acid ester remaining in the adsorption column can be eluted from the adsorption column. The amount of the nonpolar solvent to be passed is not particularly limited as long as it is an amount capable of eluting the remaining tall fatty acid ester.

  When performing the above (II), specifically, an inorganic adsorbent, a tall fatty acid ester reaction liquid, and, if necessary, a nonpolar solvent (for example, the same as described above) may be added to the reactor and stirred. . By adding a nonpolar solvent, the effect of promoting the separation and removal of polar substances can be expected.

  In said (II), it is preferable to add an inorganic adsorbent to the said tall fatty acid ester reaction liquid in the ratio used as 100 mass parts or less with respect to 100 mass parts of inorganic adsorbents. Thereby, the polar substance contained in the tall fatty acid ester reaction liquid can be efficiently adsorbed to the inorganic adsorbent. When the amount of the tall fatty acid ester reaction solution exceeds 100 parts by mass with respect to 100 parts by mass of the inorganic adsorbent, the total amount of the polar substance may not be adsorbed by the inorganic adsorbent.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to a following example.
In addition, the acid value and the measuring method of a sulfur content in the following Examples are as follows.
<Acid value> It measured by the potentiometric titration method according to JIS-K0070.
<Sulfur content> Measured by a microcoulometric titration method according to JIS-K2541-2.

Example 1
In a glass four-necked flask equipped with a stirrer, thermometer, nitrogen gas inlet tube, Liebig condenser and drain tube, tall fatty acid ("Hartol FH" manufactured by Harima Kasei Co., Ltd .; from the actual tall oil rectification plant Tall fatty acid produced, acid value: 190 mgKOH / g, sulfur content: 520 mass ppm) 300.0 g, butanol 115.8 g, paratoluenesulfonic acid (reagent special grade) 1.5 g, and xylene 50.0 g And stirred at 100-140 ° C. for 2 hours under reflux of xylene / butanol, and after performing esterification reaction while discharging the generated water through a drain pipe, butanol and xylene were distilled off to give tall fatty acid butyl ester 380.1 g of a reaction solution was obtained. The acid value of this tall fatty acid butyl ester reaction solution was 3.7 mg KOH / g.

Next, silica gel (“Wakogel C300” manufactured by Wako Pure Chemical Industries, Ltd .; pore diameter: 7 nm, pore volume: 0.8 mL / g, specific surface area: 450 m ² / g, particle size: 45) is placed on a glass adsorption column having a diameter of 50 mm. ˜75 μm is 75% or more and 75 μm residue is 5% or less) 30.0 g was filled by a hexane wet filling method. Through this adsorption column, 300.0 g of the tall fatty acid butyl ester reaction solution obtained above was passed at an elution rate of 0.25 mL / cm ² · min, and the eluate eluted from the bottom of the adsorption column was recovered. Further, 900.0 g of hexane was passed through at the same elution rate as described above, and the eluent eluted from the bottom of the adsorption column was recovered and mixed with the previously recovered eluent. From this mixed eluent, hexane was distilled off by distillation to obtain 282.3 g of tall fatty acid butyl ester. The acid value of the obtained tall fatty acid butyl ester was 0.4 mgKOH / g, and the sulfur content was 37 mass ppm.

(Example 2)
In a glass four-necked flask equipped with a stirrer, thermometer, nitrogen gas inlet tube, Liebig condenser and drain tube, tall fatty acid ("Hartol FH" manufactured by Harima Kasei Co., Ltd .; from the actual tall oil rectification plant The produced tall fatty acid was charged with 100.0 g of acid value: 190 mg KOH / g, sulfur content: 520 mass ppm), 541.9 g of methanol, and 5.0 g of paratoluenesulfonic acid, and 65-70 under methanol reflux. After stirring for 16 hours at 0 ° C. and carrying out an esterification reaction, methanol and product water were distilled off to obtain 1050.9 g of a tall fatty acid methyl ester reaction solution. The acid value of this tall fatty acid methyl ester reaction solution was 8.4 mgKOH / g.

Next, silica gel (“Wakogel C300” manufactured by Wako Pure Chemical Industries, Ltd .; pore diameter: 7 nm, pore volume: 0.8 mL / g, specific surface area: 450 m ² / g, particle size: 45) is placed on a glass adsorption column having a diameter of 50 mm. ˜75 μm is 75% or more and 75 μm residue is 5% or less) 30.0 g was filled by a hexane wet filling method. Through this adsorption column, 100.0 g of the tall fatty acid methyl ester reaction solution obtained above was passed at an elution rate of 0.25 mL / cm ² · min, and the eluate eluted from the bottom of the adsorption column was recovered. Further, 600.0 g of hexane was passed at the same elution rate as described above, and the eluent eluted from the bottom of the adsorption column was recovered and mixed with the previously recovered eluent. From this mixed eluent, hexane was distilled off by distillation to obtain 90.5 g of tall fatty acid methyl ester. The acid value of the obtained tall fatty acid methyl ester was 0.2 mgKOH / g, and the sulfur content was 39 mass ppm.

(Example 3)
A stainless steel cylindrical tube having an inner diameter of 15 mm and a length of 250 mm was charged with 100.0 g of sulfated zirconia (pellet-like reagent) to obtain a flow reactor. Stainless steel tubes (outer diameter: 1.58 mm, inner diameter: 1.0 mm) for supplying raw materials and flowing out the reaction solution were attached to both ends of the reactor, and the entire cylindrical tube was immersed in a constant temperature oil tank set at 180 ° C. On the other hand, tall fatty acid ("Hartol FA-1" manufactured by Harima Chemicals Co., Ltd .; tall fatty acid produced from an actual tall oil rectification plant, acid value 194 mg KOH / g, sulfur content 100 mass ppm) 552.0 g and methanol A solution in which 305.6 g was mixed was prepared, and this was sent to the flow-through reaction tube at a flow rate of 1 mL / min by a quantitative plunger pump. The reaction liquid flowing out from the flow reactor was collected 2 hours after the start of liquid feeding, and methanol and reaction product water were distilled off from this reaction liquid to obtain 445.0 g of tall fatty acid methyl ester. A one-stage reaction is performed, and the tall fatty acid methyl ester obtained here is referred to as “the first fatty acid methyl ester after the first stage reaction”). After this first stage reaction, the acid value of the tall fatty acid methyl ester was 42.4 mgKOH / g.

  Next, a solution in which 440.0 g of tall fatty acid methyl ester obtained after the first-stage reaction and 244.0 g of methanol were mixed was prepared, and this was added to the 1 mL / mL by a quantitative plunger pump as in the first-stage reaction. The solution was fed to the flow reaction tube at a flow rate of minutes. The reaction liquid flowing out from the flow reactor was collected 2 hours after the start of liquid feeding, and methanol and reaction product water were distilled off from this reaction liquid to obtain 336.5 g of tall fatty acid methyl ester (obtained here). The tall fatty acid methyl ester is referred to as “after the second stage reaction, the tall fatty acid methyl ester”). After this second stage reaction, the acid value of tall fatty acid methyl ester was 24.6 mgKOH / g.

Next, silica gel (“Wakogel C300” manufactured by Wako Pure Chemical Industries, Ltd .; pore diameter: 7 nm, pore volume: 0.8 mL / g, specific surface area: 450 m ² / g, particle size: 45) is placed on a glass adsorption column having a diameter of 50 mm. ˜75 μm is 75% or more and 75 μm residue is 5% or less) 30.0 g was filled by a hexane wet filling method. Through this adsorption column, 60.0 g of tall fatty acid methyl ester after the second stage reaction obtained above was passed at an elution rate of 0.125 mL / cm ² · min, and the eluate eluted from the bottom of the adsorption column was recovered. . Furthermore, 400.0 g of hexane was passed through at the same elution rate as described above, and the eluent eluted from the bottom of the adsorption column was recovered and mixed with the previously recovered eluent. From this mixed eluent, hexane was distilled off by distillation to obtain 51.5 g of tall fatty acid methyl ester. The acid value of the resulting tall fatty acid methyl ester was 0.1 mgKOH / g, and the sulfur content was 9 mass ppm.

Based on the above results, esterification reaction is performed using relatively inexpensive tall fatty acid as a raw material, and if the difference in polarity between tall fatty acid ester and other impurities is used, an adsorption column is used without using a special device. It can be seen that high-quality tall fatty acid esters can be obtained by a simple operation.
Furthermore, when the high-quality tall fatty acid esters obtained in Examples 1 to 3 were respectively used for biodiesel fuel, the environmental load related to the consumption of light oil could be reduced.

Claims (4)

A tall fatty acid ester reaction liquid is obtained by an esterification reaction using tall fatty acid containing 1 to 5% by mass of rosin acid and lower alcohol as raw materials, and this reaction liquid is passed through an adsorption column packed with an inorganic adsorbent. A method for producing a tall fatty acid ester having an acid value of less than 0.5 mg KOH / g and a sulfur content of 50 ppm by mass or less ,
Allowing the tall fatty acid ester reaction solution to flow at a rate of 100 parts by mass or less with respect to 100 parts by mass of the inorganic adsorbent and at an elution rate of 0.01 to 1.00 mL / cm ² · min. A method for producing a tall fatty acid ester. A tall fatty acid ester reaction liquid is obtained by an esterification reaction using 1 to 5% by mass of rosin acid containing rosin acid and lower alcohol as raw materials, and an inorganic adsorbent is added to the reaction liquid and stirred to give an acid value of 0. A method for producing a tall fatty acid ester having a sulfur content of less than 5 mg KOH / g and a sulfur content of 50 mass ppm or less ,
A method for producing a tall fatty acid ester , wherein the inorganic adsorbent is added at a ratio of 100 parts by mass or less with respect to 100 parts by mass of the inorganic adsorbent . The method for producing a tall fatty acid ester according to claim 1 or 2 , wherein the lower alcohol used as a raw material is an alkyl alcohol having 1 to 4 carbon atoms. The method for producing a tall fatty acid ester according to any one of claims 1 to 3 , wherein the inorganic adsorbent is at least one selected from the group consisting of activated carbon, zeolite, activated alumina, activated clay, and silica gel.