JP2938586B2 - Method for producing α-sulfofatty acid ester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a .alpha.-sulfofatty acid ester having a good hue, which is useful in the field of laundry and detergents, especially detergents for washing textiles. The present invention relates to a method for producing an α-sulfofatty acid ester having good hue from a basic oil or fat.

[0002]

2. Description of the Related Art Methods for producing .alpha.-sulfofatty acid esters from fats and oils, especially natural fats and oils, have been studied for many years, and the quality of fatty acid esters to be sulfonated has been improved.
Many documents and patents have been reported on sulfonation conditions, purification conditions, and the like.

[0003] It is well known that the quality of fatty acid esters correlates with the coloration of the sulfonated reactants. That is, it is required that the fatty acid ester to be sulfonated at the α-position has no double bond or contains a small amount thereof, and does not contain other reactive groups, especially hydroxyl groups. For example, Tokuhei 01
According to -50223, the iodine value of the fatty acid ester is required to be 5 or less, preferably 2 or less.

[0004] Therefore, a method of selecting an oil or fat as a raw material of a fatty acid ester and hydrogenating and / or distilling a fatty acid ester used as a raw material for a sulfonation reaction is usually performed.

According to Japanese Patent Publication No. 50223/1990, the following two methods are disclosed for obtaining an α-sulfofatty acid ester from vegetable oils and / or animal oils and fats.

A method of hydrogenating an oil or fat to obtain a hardened oil, then obtaining a saturated fatty acid ester from the hardened oil or fat, and sulfonating the ester.

[0007] In this method, a fatty acid ester is obtained from fats and oils, and then the fatty acid ester is hydrogenated to obtain a saturated fatty acid ester, which is sulfonated.

[0008]

However, according to the above-mentioned method and method, when the unsaturated bond is completely saturated by hydrogenating the fat or oil or the fatty acid ester, the catalyst used for this is the starting oil or fat or the fatty acid ester. It is poisoned by impurities contained therein (for example, sulfur, nitrogen, and phosphorus-containing compounds), which leads to an increase in the amount of catalyst used or a problem that it cannot be completely saturated. For this reason, a purification step such as clay treatment is required in advance, and as a result, in order to obtain an α-sulfofatty acid ester having good hue, there is a great disadvantage that the production cost is increased.

[0009]

Means for Solving the Problems The present inventors have made intensive studies in order to achieve the above object, and as a result, have found that in a method for producing an α-sulfofatty acid ester from fats and oils, a fatty acid ester to be subjected to sulfonation is obtained. A fatty acid is obtained by hydrolysis of fats and oils, and then hydrogenated to substantially completely saturate the double bond, and then further esterified with a monohydric alcohol to obtain the fatty acid ester thus obtained. On the other hand, it has been found that when the fatty acid ester is subsequently sulfonated by adding an alkali substance and then distilling the fatty acid ester, an α-sulfo fatty acid ester having an extremely good hue can be produced, thereby completing the present invention.

That is, the present invention is characterized in that the following steps (a) to (e) are carried out in producing an α-sulfofatty acid ester from vegetable oils and / or animal oils and fats.
-To provide a method for producing sulfo fatty acid esters.

Step (a) Step of hydrolyzing vegetable and / or animal fats and oils to fatty acids Step (b) Step of hydrogenating the fatty acids obtained in step (a) Step (c) In step (b) Esterification step of the obtained hydrogenated fatty acid Step (d) Step of distilling the fatty acid ester obtained in the step (c) in the presence of an alkali substance Step (e) Distilled fatty acid ester obtained in the step (d) The present invention is described in more detail below.

As described above, in the method for producing an α-sulfofatty acid ester of the present invention, a fatty acid is obtained by hydrolysis of fats and oils, and then this is hydrogenated to completely saturate the double bond, and then further monovalent. The method comprises esterification with an alcohol, addition of an alkali to the obtained fatty acid ester and distillation, followed by sulfonation and bleaching of the fatty acid ester. At this time, the fatty acid obtained by hydrolysis is
It is preferred to distill before hydrogenation into a distilled fatty acid having a low fatty acid glyceride content.

In the process of the present invention, to obtain a fatty acid ester, the fatty acid glyceride is removed to the extent that the fatty acid glyceride is hardly contained in an amount of 0.2% by weight or less based on the weight of the fatty acid ester to be sulfonated, and the iodine value is 0.1 or less. The process is characterized in that a nearly completely saturated fatty acid ester is introduced into the sulfonation step.

In order to obtain a fatty acid ester satisfying the above conditions, a method of transesterifying a vegetable oil and / or animal fat and oil with a lower alcohol (hereinafter referred to as a transesterification method) is a method of obtaining a fatty acid ester. It is difficult to reduce fatty acid glyceride to a level of 0.2% by weight or less even by distilling the ester, and if it is attempted to reduce the level to this level, precision distillation must be repeated many times, which is extremely economical in production. It turned out to be disadvantageous.

On the other hand, the fats and oils are hydrolyzed, and the obtained unsaturated fatty acids are used as a raw material to esterify with a monohydric alcohol,
The method of obtaining a saturated fatty acid ester and then distilling the saturated fatty acid ester, compared with the transesterification method described above, the fatty acid glyceride amount present in the saturated fatty acid ester,
Although lowering, it was still difficult to reduce the content to 0.2% by weight or less in this method. It is because fatty acid glycerides present in saturated fatty acid esters are mostly fatty acid monoglycerides, and the boiling points of fatty acid esters and fatty acid monoglycerides to be removed by distillation are similar depending on the carbon chain length of fatty acids. This is because it was difficult to separate fatty acid glyceride from fatty acid ester by distillation.

However, the present inventors have conducted intensive studies on a method for efficiently separating and removing fatty acid glycerides from fatty acid esters by distillation. As a result, an appropriate amount of an alkali substance, preferably 5 to 500 ppm of an alkali substance, is present with respect to the fatty acid ester. The present inventors have found that the fatty acid glyceride can be efficiently removed by distilling the fatty acid ester below. Although the details of the reason are not yet clear, the transesterification reaction between the fatty acid ester and the fatty acid glyceride occurs during the distillation by the alkali substance, and the high-boiling long-chain fatty acid monoglyceride is concentrated during the distillation residue. It is presumed that it is possible.

The alkaline substance used in the present invention is not particularly limited, and examples thereof include sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, potassium hydrogen carbonate and the like. The amount of the alkaline substance used in the present invention is preferably 5 to 500 ppm based on the fatty acid ester,
More preferably, it is 15 to 300 ppm. When the amount of the alkaline substance is below this range, the fatty acid monoglyceride cannot be efficiently removed by distillation, while when the amount of the alkaline substance exceeds this range, the resulting α-sulfofatty acid ester has a good hue. Has no effect.

Here, various fats and oils can be used as raw materials. Specific examples include vegetable oils such as palm oil, coconut oil, and palm kernel oil, and animal oils such as beef tallow and lard. The hydrolysis and distillation of fats and oils are carried out in a usual manner. Generally, the fatty acid glyceride content of the distilled fatty acid obtained is 1.0% or less,
Most are less than 0.8%. The distilled fatty acid is then saturated with hydrogen. Hydrogenation is performed by a known method. Typically
At a temperature of 150 to 200 ° C, nickel catalysts such as flake Ni and stabilized Ni are used. The hydrogenated fatty acids have an iodine value of 1 or less, preferably 0.5 or less. Subsequently, esterification is carried out with a lower monohydric alcohol, particularly preferably with methanol or ethanol. The esterification is carried out in a customary manner, for example by distilling fatty acids kept at a temperature of from 90 to 120 DEG C., as a catalyst a mineral acid, preferably a mixture of 0.1 to 0.3% of sulfuric acid and a lower monohydric alcohol with respect to the distilled fatty acid. Esterification is carried out by blowing alcohol at 0.5 to 2.0 moles / distilled fatty acid / 1 hour until the acid value becomes 0.5 or less, preferably 0.3 or less. Thereafter, the sulfuric acid used as the catalyst is removed by washing with water or dry neutralization with sodium methylate or the like. The thus obtained fatty acid ester before distillation is
Contains 0.6-1.0% fatty acid glyceride and has an iodine value
It is about 0.3.

Next, distillation is finally performed to obtain a fatty acid ester having a target quality. According to the present invention, it is preferably 5 to 500 ppm, more preferably 15 ppm to the fatty acid ester.
Distillation is performed by adding ~ 300 ppm of an alkali metal hydroxide, preferably potassium hydroxide. Distillation conditions vary depending on the raw material fat used, for example, when using palm oil,
Vacuum degree 2-5mmHg, tower top temperature 120-198 ℃, tower bottom temperature 1
Distill at 70-240 ° C. The fatty acid ester prepared by this method is then sulfonated in a known manner in a film reactor with a mixture of gaseous sulfur trioxide and an inert gas, for example at a temperature of about 70-130 ° C., The sulfonated product is obtained by aging the product at 60-130 ° C. The degree of sulfonation is preferably 90% or more, more preferably 92% or more, for example, 94% or more;
Particularly, a degree of sulfonation of 95% or more is desirable. The sulfonated product is neutralized with a sodium hydroxide solution, and then bleached with a sodium hypochlorite solution to obtain an intended α-sulfofatty acid ester, which is used as a raw material for a detergent.

[0020]

According to the method for producing an α-sulfofatty acid ester of the present invention, a light-colored α-sulfofatty acid ester required as a detergent can be produced in high yield and the sulfonation rate can be increased. At the same time, it can be used as a useful alternative in modern laundry composition manufacture, and even on a large scale industrial production.

[0021]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples. Unless indicated otherwise,% means% by weight.

Example 1 Palm oil was hydrolyzed and distilled, and palm fatty acid was added to the fatty acid by adding 0.04% (as a nickel component) of a flake nickel catalyst, and the hydrogen pressure was 5 kg / cm ² and the reaction temperature was 150 to 200 ° C.
For 2 hours to obtain a hardened fatty acid having an iodine value of 0.21. Subsequently, esterification is performed with methanol to obtain a fatty acid ester. This fatty acid ester had an iodine value of 0.21 and a fatty acid glyceride content of 0.81%. This fatty acid ester is further added to the fatty acid ester at 30 ppm as potassium hydroxide with a 10% potassium hydroxide-methanol solution, the degree of vacuum is 5 mmHg, the top temperature is 198 ° C or lower, and the bottom temperature is 240 ° C.
Distilled below ℃. Distillation rate 97.9%, distillation residue 1.14
%Met. The distillation residue contained 48.5% of fatty acid glycerides, and the calculation revealed that most of the fatty acid glycerides contained in the distillation raw material were concentrated in the distillation residue. The distillate fraction has the quality shown in Table 1.

The above fatty acid ester was reacted in a laboratory stainless steel film reactor (inner diameter 14 mmφ × 2.3 m) with a reaction molar ratio (sulfur trioxide / methyl ester) = 1.2 and a reaction temperature =
Sulfonation was carried out at 80 ° C, and the resulting sulfonated mixture was heated and aged at 80 ° C for 60 minutes to obtain α-sulfofatty acid methyl ester. This α-sulfofatty acid ester is
The mixture was dropped and mixed in a 3.5% caustic soda solution with stirring, and neutralized at a neutralization temperature of 40 to 60 ° C. so as to have a pH of 7, to obtain an α-sulfofatty acid ester salt solution. The active ingredient in this solution was measured by the Epton method, and 4.0% by weight of sodium hypochlorite was added to the active ingredient, and bleached at 80 ° C for 60 minutes.
The pH was adjusted to 7 with an 85% phosphoric acid solution to obtain a bleached α-sulfofatty acid ester salt. The active ingredient of this bleached product was measured by the Epton method, and the hue of a 10% solution of the active ingredient was measured. The sulfonation reaction rate of the α-sulfofatty acid ester salt solution before bleaching was also measured by a petroleum ether extraction method. Table 1 shows the measurement results.

Comparative Example 1 A fatty acid ester was produced in the same manner as in Example 1 except that the fatty acid ester was distilled without using a 10% potassium hydroxide-methanol solution. The distillation yield of the fatty acid ester is 95.3%, and the distillation fraction has the quality shown in Table 1. The fatty acid ester was subjected to sulfonation-neutralization-hyposub bleaching in the same manner as in Example 1, and the hue was evaluated. Table 1 shows the measurement results.
Shown in

COMPARATIVE EXAMPLE 2 Palm oil was transesterified with methanol, subsequently distilled and hardened, potassium hydroxide was added and distilled as in Example 1. Distillation yield of fatty acid ester is 95.3%
The distillation fraction has the quality shown in Table 1. The fatty acid ester was subjected to sulfonation-neutralization-hyposub bleaching in the same manner as in Example 1, and the hue was evaluated. Table 1 shows the measurement results.

[0026]

[Table 1]

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-57-126895 (JP, A) JP-A-62-298570 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C07C 309/00 C07C 303/00 C11D 1/28 CA (STN)

Claims (3)

(57) [Claims] 1. A method according to claim 1, wherein a vegetable oil and / or an animal oil
-A process for producing an α-sulfofatty acid ester, which comprises performing the following steps (a) to (e) in producing a sulfofatty acid ester. Step (a) Step of hydrolyzing vegetable and / or animal fats and oils to fatty acids Step (b) Step of hydrogenating the fatty acids obtained in step (a) Step (c) Obtained in step (b) Step (d) of distilling the fatty acid ester obtained in step (c) in the presence of an alkaline substance. Step (e) Sulfonation, neutralization and bleaching steps of the distilled fatty acid ester obtained in step (d). 2. The method according to claim 1, wherein the fatty acid to be hydrogenated in the step (b) is a distilled fatty acid obtained by distilling the fatty acid obtained in the step (a). A method for producing a sulfo fatty acid ester. 3. The method according to claim 1, wherein in the step (d) of distilling the fatty acid ester, the alkali substance is present in an amount of 5 to 500 ppm based on the fatty acid ester to be distilled. 2. The method for producing an α-sulfofatty acid ester according to 2.