JPH0341520B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for saponifying organic acids or their esters, particularly fatty acid glyceride esters. More specifically, the present invention provides free fatty acids, fats,
The present invention relates to a method for producing soaps and lubricating greases from oils and other lipid materials.

As in traditional soap making processes, the preparation of alkali metal salts of organic acids by saponification of the organic acid esters is usually carried out using an alkali metal hydroxide base, an organic acid ester, and water as the reaction medium. Such methods require thermal energy to initiate and sustain the saponification reaction and to remove excess water from the saponification product (soap); furthermore, the saponification product is usually sticky and It is difficult to handle and cannot be recovered by simple methods.

It is quite possible that energy costs in any industrial process can account for a large portion of the total cost of producing the final product. Therefore, a method that can relatively reduce energy costs without compromising the quality or yield of the final product could benefit the above method. This also applies to soap production.
The reduction in thermal energy usage would then translate significantly into overall cost savings in soap production.

Saponification of lipids using solid caustic soda finely dispersed in a polar aprotic organic solvent such as acetone to obtain soap powder, glycerin and unsaponifiables remaining in the solvent is a Seifen-Ole-
Ivanov in Fetle-Wasche 102 (1976) No. 16, page 459.
proposed by et al. Ivanov requires that saponification involves phase separation of fatty acids as soap soda from glycerin and unsaponifiables without the need for additional liquid-liquid or liquid-solid extraction.

In a liquid reaction mixture containing an alkyl nitrile,
Soda of organic carboxylic acids can be prepared by saponifying the corresponding organic carboxylic esters with concentrated aqueous solutions of caustic soda or lithium hydroxide, separating the salts thus formed from the reaction mixture, and removing excess alkylnitrile from these salts. and producing lithium salts is a U.S. Patent No.
No. 4,075,234 (assigned to Procter & Gamble Co., Ltd. by Peterson).

We saponified organic acids or their esters with concentrated aqueous alkaline solutions in the presence of water-miscible organic solvents other than alkyl nitriles and inorganic salts at lower temperatures than those used in conventional soap making. It has been discovered that by doing so, the soap produced can be obtained in the form of a finely divided dry powder without the need for dehydration before conversion into a soap product.

The expressions "saponification" and "saponification" are commonly used to describe the process of reacting an organic acid ester with an alkali metal hydroxide to form the corresponding alkali metal salt of the organic acid, i.e., a soap. should be explained. However, as explained herein below, soaps can also be produced by reacting organic salts with alkali metal hydroxides; this latter reaction is thus also referred to as "saponification" and "saponification". The expression is described herein.

Therefore, the new method can significantly save energy costs compared to the traditional method. Additionally, soaps made by the new process have been found to be easier to produce soap products, such as soap tablets, than is experienced with traditional soap tablet manufacturing.
For example, dry soap powder can be readily deodorized by vacuum heating if desired, or in some cases bleached by moderate heat without adversely affecting the soap itself. Traditionally produced "wet" soaps cannot be deodorized or bleached this easily.

By using a concentrated aqueous solution of an alkaline base instead of the solid base proposed by Ivanov et al.
The speed and control of the saponification process becomes much easier to adjust, and more importantly, the resulting soap
It was found that there is no contamination with solid bases, as was seen from experience when testing the method proposed by Ivanov et al. under practical conditions. The presence of inorganic salts also results in unexpectedly high yields of soap powder.

It has also been noted that fats, fatty acids and other lipid materials that can be used in soap making dissolve more easily in acetone than in alkyl nitriles such as acetonitrile advocated by Peterson. Acetone therefore provides a better medium for carrying out the saponification process.

The present invention provides a method for producing an alkali metal salt of an organic carboxylic acid. The process involves saponifying the corresponding organic carboxylic acids, their esters or mixtures thereof with concentrated aqueous solutions of alkali metal hydroxides in the presence of inorganic salts in a liquid reaction medium consisting of acetone, and removing the organic salts from the reaction medium. separating and removing excess acetone from the organic salt.

Organic Carboxylic Acids The organic carboxylic acids that can be saponified according to the present invention will typically be straight or branched chain fatty acids having from 6 to 24 carbon atoms in the molecule. Usually mixtures of two or more such acids will be used, such as free fatty acid mixtures produced by distillation or decomposition of natural fats and oils.

Examples of commercially available free fatty acid mixtures that can be used effectively are: cracked and distilled tallow fatty acids, cracked and distilled palm fatty acids, cracked and distilled coconut fatty acids, acidic oils of nut, vegetable and fish origin, cracked and distilled tallow fatty acids. Volatile short chains (C ₆ ~
_C10 ) acid concentrates, and undistilled residues from vacuum distillation cracked fatty acids.

Organic Carboxylic Acid Esters The organic acid esters that can be saponified according to the present invention will usually be simple alkyl or aryl esters, or mixtures thereof. or particularly high grade materials, typically glycerin esters such as triglycerides, as well as mono- or di-glycerides or triglycerides and mixtures thereof, which constitute the major proportion of the material contained in fats and oils of animal or vegetable origin. Something can happen. Specific non-limiting examples of animal or vegetable oils include lard, tallow, coconut oil, palm oil,
Various by-products from animal fat melting operations, oils from oilseeds such as soybeans, sunflower seeds, cottonseed, and other fats and oils with unusually high acid values due to the oxygen and microbial changes that occur. including.

Furthermore, examples of commercially available sources of fats and oils are
Bailey's "Industrial Oil and Fat Products";
3rd edition, edited by D. Swern (1964), pp. 153-164.

According to one aspect of the invention relating to soap production for use in lubricating greases, the organic acid ester is preferably a _C6 to _C24 alkyl organic acid ester.

According to another aspect of the invention relating to the production of industrial or domestic soaps, the organic acid ester is preferably a _C6 - _C20 , most preferably _C12 - _C18 alkyl organic acid ester.

The reaction does not appear to depend on the nature of the organic acids or their esters used. Therefore, alkali metal salts of organic acids or branched or aryl organic acids with chain lengths shorter or longer than those mentioned above can be prepared by the process of the invention by saponification of the corresponding organic acids or their esters. You can also.

Inorganic Salts Inorganic salts are used in the process of the invention to increase saponification rate and soap yield. Preferred salts are alkali metal halides, sulfates, or phosphates.

Preferred salts useful in increasing the percent yield of the resulting soap are lithium chloride, sodium acetate, sodium tripolyphosphate, common salt, sodium sulfate, and sodium iodide.

Preferred salts are sodium tripolyphosphate, common salt and sodium sulfate for reasons of economy and the need to bleach the soap.

Other inorganic salts or mixtures of the above salts with other inorganic salts can also be used.

The amount of inorganic salt used is usually expressed in terms of the organic acids or their esters to be saponified.
It will consist of 0.01M to 2M. In practical terms, the amount of inorganic salt used is typically 1-10% by weight of the organic acid or ester thereof to be saponified;
Preferably it will consist of 2-5%.

Alkali Metal Hydroxide The alkali metal hydroxide used may be caustic soda or caustic potash or lithium hydroxide or mixtures thereof. The amount of hydroxide added to the reaction mixture will depend on the amount of organic acid included and its acid value, or the amount of organic acid ester included and its saponification value.

Acid value is defined as the exact number of mg of caustic potassium required to neutralize the free acidity of 1 g of organic acid ester. The acid value is determined by Hilditch's “The Industrial
It can be determined by the method described in "Chemistry of the Fats and Waxes", p. 43 (1949).

The saponification value is defined as the number of mg of caustic potassium required to completely saponify 1 g of organic acid ester. The saponification value is determined by Hilditch's "The Industrial Chemistry".
of the Fats and Waxes", p. 42 (1949).

The amount of alkali metal hydroxide used to completely saponify an organic acid or ester can therefore be calculated from the acid number of the acid or the saponification number of the ester, respectively, and is calculated from the theoretical stoichiometric amount. Probably. However, it is preferred to use slightly less than the stoichiometric amount of hydroxide to ensure that the soap actually formed is not contaminated with unused hydroxide. Ideally, the amount of hydroxide used is significantly less than the stoichiometric amount. Any unsaponifiable organic acid or ester remaining in the acetone solution, which can be as little as 50% of the stoichiometric amount, for example, is separated, recovered and, if desired, separated into another for subsequent saponification. Added to organic acids or esters. However, amounts of alkali base in excess of the stoichiometric amount, for example up to 10% more than the stoichiometric amount, can be used if complete oxidation of the organic acid or ester is to be achieved.

The concentration of the aqueous alkali metal hydroxide solution used depends on the solubility of the selected base in water. For example, if the hydroxide is caustic soda, the concentration of the aqueous caustic soda solution used should be at least 20% by weight, preferably as high as 50% by weight or more. The ideal solution to use contains about 40% caustic soda by weight. On the other hand, if the hydroxide is lithium hydroxide, the concentration of the aqueous lithium hydroxide solution used should be at least 7% by weight, preferably as high as 17% by weight. It is close to a saturated aqueous solution of lithium hydroxide.

Liquid Reaction Medium The liquid reaction medium in which the saponification reaction is carried out consists of acetone in an amount sufficient to dissolve most or all of the organic acids or esters thereof. The liquid medium will also contain at least a small amount of water. Most of it will come from the aqueous alkali metal hydroxide added to initiate the saponification reaction.
Therefore, the amount of water included in the liquid reaction medium will normally be sufficient to maintain the hydroxide at least in solution while saponification proceeds. It is important to ensure that the hydroxide does not precipitate during this reaction and does not contaminate the soap thus formed. The amount of water contained in the reaction mixture is not excessive, thus ensuring that the soap formed as a result of saponification does not lose its granular, powdery character and does not become sticky and difficult to handle due to overhydration. It is also important.

The amount of water in the reaction mixture will depend on the aqueous solubility of the alkali base used, but generally should not exceed 10% of the total reaction mixture and should not exceed 5% of the total reaction mixture.
Preferably no more than %.

Process When carrying out the process of the invention for preparing alkali metal salts of organic carboxylic acids, the organic carboxylic acids or their esters or mixtures thereof are prepared by mixing alkali metal water in a liquid reaction medium consisting of acetone in the presence of an inorganic salt. It is saponified by a concentrated solution of oxide. The organic salt or salts thus formed, ie the soap or soaps, are separated from the reaction medium and excess acetone is removed from the soap or soaps.

In a preferred method, the organic acids or their esters are first dissolved in acetone and the concentrated aqueous solution of the alkali metal hydroxide and the salt are then added with stirring. The liquid reaction mixture can be heated to a temperature of about 56° C., the boiling point of acetone, without the application of high pressure. The saponification can then be continued until completion, preferably under reflux.

The soap is formed as a finely divided powder solid in the reaction vessel, which is then easily removed, e.g. by filtration, and then desolvated, e.g. by applying heated air or steam, to remove the acetone and dried into finely divided powders. You can get soap powder.

The saponification treatment period will generally depend on the treatment temperature and, if an organic acid ester is used, especially those of natural origin, its acid number, which is a measure of the free fatty acids that may be present. The saponification reaction usually occurs at atmospheric pressure, at about 56%, which is the boiling point of acetone.
It is generally an exothermic reaction, although it is preferred to apply mild heating to allow the reaction to proceed at <0>C. Alternatively, processing can be carried out at higher temperatures, provided that pressures other than normal atmospheric pressure are applied.

In general, it can be stated that the saponification period is shorter when free fatty acids are used than when their corresponding esters are used.

As an example, for a lipid (organic acid ester) sample with an acid number of 99, saponification at 56°C was completed in 30 minutes, whereas for another lipid sample with an acid number of 16, saponification was The mixture was not completed until heated at 56°C for 3 hours. A high acid value results in a short reaction time, whereas a low acid value results in a longer reaction time.

The soap obtained as a result of saponification will usually precipitate as a finely crystalline white powder with an average particle size of a few microns.

Microcrystalline powder soaps, as a result of separation from the liquid reaction medium and drying, will generally assume a granular form with a particle size of 0.05 to 1 mm. In one example, described in greater detail later herein, the average particle size was 0.2-0.3 mm.

The soap powder will generally be substantially anhydrous if the amount of alkali metal hydroxide used for saponification is less than the stoichiometric amount. However, if it is desired to obtain a soap powder with a sufficient amount of water to make soap products such as soap doublets, the soap powder must be desolvated, for example by steam treatment, to drive off any residual acetone and at the same time remove the soap powder from the soap powder. Preferably, the moisture content is adjusted to the desired level.

Soap powders made in this manner will not contain many of the coloring substances normally found in commercial grade animal fats. The colored substance remains in solution in the liquid reaction medium together with any unsaponifiable substances that may have been included in the starting materials.

Typically, soap yields obtained by the process of the present invention can be as high as 90% or higher.

The organic acid salts (soaps) produced according to the invention as finely divided powders can be used in the production of soap powders or flakes, such as those used in textile washing, or for use in mechanical dispensers, such as those used in public toilets. It can be used as Alternatively, finely divided soaps can be used to make shaped soap products such as soap doublets for personal or fabric washing use.

Acidification of the soap also makes it possible to recover free organic acids (free fatty acids), for example for use in animal feed, and for other purposes. As an example, the residue from the vacuum distillation of degraded tallow fatty acids as a crude source of organic acids and esters can be treated according to the present invention and, after acidification, provide an inexpensive source of free fatty acids for use in the production of animal feed. can.

The organic acid lithium salts produced according to the invention as finely divided powders can be used in the production of lubricating greases.

The following examples illustrate the implementation of the invention.

Example 1 Production of soap powder from triglycerides and concentrated caustic soda 50% of tallow and coconut fat at a temperature of 56°C:
To a solution of 50 g of the 50 mixture in 250 ml acetone were added 8.15 g of caustic soda dissolved in 8.15 g of water along with 2.5 g of common salt. The reaction was started with gentle warming.
Once started, the reaction mixture was kept at reflux temperature with stirring for a total of 3 hours. During this time a layer of fine white solid powder material formed within the reaction vessel.

The solid material was thickened by straining and passed through steam (to remove the acetone) to give a free-flowing sodium carboxylate (soap) corresponding to the fatty acids of the starting triglycerides in a yield of approximately 90%.

Manufacture of Bar Soap The hydrated soap powder produced by the method described above has the following formulation: Ingredients wt % Soda soap ^* 89.75 Coconut oil fatty acids 7.0 Salt 1.0 TiO ₂ 0.25 Fragrances, colorants, fragrance stabilizers 1.75 It can be used to form *Manufactured as above (approximately 10
(wt% water).

Compositions of the type described above can be extruded through standard soap making extruders and formed into bars using commercial bar soap processing techniques. An excellent bar soap product can be obtained that compares favorably with commercially available soaps.

Example 2 Production of soap powder from lower tallow 100 g of rejected tallow having a saponification value of 158 and an acid value of 84 and containing 2.5% by weight of unsaponifiables is dissolved in 500 ml of anhydrous acetone and heated to 56°C under reflux. did. To this mixture was added 31 ml of 40% W/V caustic soda aqueous solution, then 5 minutes of anhydrous sodium chloride solution was added over 5 minutes.
g was added to form a second liquid phase.

The mixture is stirred well and heated to approximately 56°C under reflux.
heated for 30 minutes. Fine particles of soap,
It was formed with a single liquid phase reaction medium containing water, glycerin, acetone, common salt, unsaponifiables and a small amount of unsaponifiable fat.

The soap powder was filtered and washed with 500 ml of acetone at 56°C. The granular soap thus obtained was free-flowing and contained less than 5% by weight of water.

Later recovered from granular soap (by acidification)
The oxidation value and acid value of the fatty acid were both 204, indicating that the ester did not precipitate with the soap at all.

The acetone reaction phase and wash phase were evaporated together until no acetone remained. Residual unsaponifiable matter contains 1.1g fatty acids, 98.8% of fatty substances
indicates that it has been converted.

In a similar test in which salt was omitted, the corresponding conversion of fatty organisms was 94%.

The soap powder thus obtained was graded and the following particle size distribution was recorded. Soap powder % particle size (mm) 2.58 1 7.6 0.71 18.3 0.5 32.4 0.36 68.5 0.18 87.6 0.11 97.5 0.053 2.5 0.053 Example 3 Production of lithium carboxylate 50 g of hydrogenated castor oil at a temperature of 56°C in 250 ml of acetone suspension; 3g of 3.9 g of anhydrous lithium hydroxide dissolved in 26 ml of water was added along with sodium tripolyphosphate. The reaction was initiated with gentle heating. Once started, the reaction mixture has a total of 21
The mixture was kept at reflux temperature (56° C.) with stirring for an hour.

The product that precipitated out of solution was isolated by vacuum filtration of the hot reaction medium and the solvent was stripped off in a vacuum desiccator. The product was a solid lithium peroxycarboxylate, with the majority being 12-hydroxycytearate lithium salt.

This lithium salt (soap) can be used in the production of industrial lubricants.

Example 4 Production of soap from rice bran oil A mixture of 20 g rice bran oil and 100 ml acetone was cooled from the boiling point and filtered at 10° C. to remove wax. The liquid was heated to 56° C. and 0.2 g of common salt was added with stirring, followed by 9.5 ml of 30% W/V caustic soda over 15 minutes. The reaction mixture is further 15
It was held at 56°C for minutes.

The soap powder was allowed to settle out of the solution and recovered by vacuum filtration. The powder was finally stripped of solvent in a vacuum desiccator and then deodorized by heating at 100° C. in vacuo. The soap powder retained its free-flowing properties when cooled.

The soap yield obtained was 94%.

Rice Bran Oil Fatty Acid Yield Fatty Acid % W/W C ₁₂ 0.5 C ₁₄ 0.8 C ₁₆ 22.8 C ₁₆ : ₁ 0.4 C ₁₈ 2.4 C ₁₈ : ₁ 38.8 C ₁₈ : ₂ 29.1 C ₁₈ : ₃ 1.2 C ₂₀ 0.8 C ₂₀ : ₁ 0.6 C ₂₁ : ₁ 0.3 C ₂₂ 0.8 C ₂₄ 1.5 Acid value 136 Saponification value 186 Unsaponifiable value 5.2% Example 5 Production of soap from palm oil Disperse 30g of palm oil in 150ml of acetone,
passed. The liquid was heated to 56° C. and 0.3 g of common salt was added, followed by 13 ml of 30% W/V caustic soda over 15 minutes. The reaction mixture was held at 56°C for an additional 1.75 hours.

The precipitated soap powder was recovered by vacuum filtration, washed with acetone, and stripped of solvent in a vacuum desiccator. A substantial amount of the yellow color due to carotene is extracted into the acetone phase, and the remaining color in the soap powder is
It was further reduced by anhydrous heating to a temperature of 100°C. The free-flowing properties of the soap powder were retained upon cooling.

The soap yield obtained was 99%.

Analysis of palm oil fatty acids Fatty acid % W/W C ₁₂ 0.1 C ₁₄ 1.0 C ₁₆ 45.7 C ₁₆ : ₁ 0.3 C ₁₇ 0.1 C ₁₈ 5.8 C ₁₈ : ₁ 38.7 C ₁₈ : ₂ 7.3 C ₂₀ 0.4 C ₂₁ : ₁ 0.6 Acid value 18 Saponification value 197 Unsaponifiable matter 0.9% Example 6 Production of potash soap from free fatty acids 1 g of common salt was added to a suspension of 100 g of PRIFAC 7920 in 100 g of acetone at 56°C, and then 50 ml of 40% W/V caustic potash was added over a period of 15 minutes. Added. The precipitated soap was removed by vacuum filtration. The soap powder was fine granular in nature, anhydrous, and white in color.

PRIFAC7920 is a major distillate of degraded tallow fatty acids. Its fatty acid analysis is as follows: Fatty acid %W/W C ₁₄ 2 C ₁₆ 25 C ₁₆ : ₁ 3 C ₁₈ 18 C ₁₈ : ₁ 44 C ₁₈ : ₂ 6 C ₁₈ : ₃ 1 C ₂₀ 1 Saponification value 201 ~207 Acid value 200~206 Iodine value 50~60

Claims (1)

[Scope of Claims] 1. A process for producing an alkali metal salt of an organic carboxylic acid, which comprises treating the corresponding organic carboxylic acid, its ester, or a mixture thereof in a liquid reaction medium containing acetone in the presence of an inorganic salt. , saponifying with a concentrated aqueous alkali metal hydroxide solution, separating an organic salt from the reaction mixture, and removing excess acetone from the organic salt. 2. The method of claim 1, wherein the organic carboxylic acid comprises a mixture of free fatty acids having from 6 to 24 carbon atoms in the molecule. 3. The method according to claim 1, wherein the organic acid ester is a glyceride ester. 4. The method according to claim 1, wherein the organic acid ester is a _C6 to _C24 alkyl carboxylic acid ester. 5. The method according to claim 4, wherein the organic acid ester is a _C12 to _C18 alkyl carboxylic acid ester. 6. The method according to any one of claims 1 to 5, wherein the alkali metal hydroxide is caustic soda or caustic potash. 7. The method according to claim 6, wherein the alkali metal hydroxide is in the form of an aqueous solution containing 20 to 50% by weight of caustic soda or caustic potash. 8. Any one of claims 1 to 5, wherein the alkali metal hydroxide is lithium hydroxide.
The method described in section. 9. The method according to claim 8, wherein the alkali metal hydroxide is in the form of an aqueous solution containing 10 to 17% by weight of lithium hydroxide. 10. The method according to any one of claims 1 to 9, wherein the inorganic salt is an alkali metal halide, sulfate, or phosphate. 11. The method according to claim 10, wherein the inorganic salt is sodium sulfate, common salt, or sodium tripolyphosphate. 12 The inorganic salt is present in claim 1 in an amount of 1 to 10% by weight of the organic acid ester in the reaction medium.
The method according to item 0 or item 11.