JPH0317040A - Solution of rare earth soap and production thereof - Google Patents

Abstract

PURPOSE:To obtain a solution of rare earth soap capable of reducing viscosity without adding a specific additive, hardly having admixture of water by increasing more an amount of organic acid based on rare earth element than a fixed amount and dissolving rare earth soap in an organic solvent. CONSTITUTION:An aqueous solution of rare earth element such as cerium, neodymium, lanthanum or praseodymium and an aqueous solution of alkali soap of organic acid containing an organic acid (e.g. caprylic acid, lauric acid or naphthenic acid) having >=3.2 acid equivalents based on atoms of the rare earth element in the aqueous solution of the rare earth element are subjected to double decomposition reaction in the presence of an organic solvent (preferably higher flash point in terms of handleability and preferably rich in aromatic property in terms of solubility) to give a solution of rare earth soap. The soap solution has a new composition which will neither settle nor separate for a long period of time and can extremely decrease water content. The soap solution is useful as a combustion improver for fuel oil, etc., and a drying agent for paint, etc.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to an organic solvent solution of a rare earth soap as a new composition and a method for producing the same. Organic solvent solutions of rare earth soaps are mainly used as combustion improvers for fuel oil and the like, paint drying agents, and the like. [Prior Art] Oil-soluble rare earth element compounds, especially rare earth soap solutions in organic solvents are mainly used as combustion improvers for fuel oil and paint drying agents to improve combustion efficiency. Rare earth elements generally have a trivalent valence, so organic acid salts of rare earth soaps have a stoichiometric acid equivalent of 3.0 to the number of rare earth atoms. Equivalent amounts were used. On the other hand, in order to increase the metal concentration and reduce the amount used, a basic, oil-soluble cerium soap with a ratio of the number of acid equivalents to the number of cerium atoms of 3 or less has been proposed (JP-A-53 -129
Publication No. 07). However, rare earth soaps made of organic acids with a stoichiometric amount or less, that is, an acid equivalent of 3.0 or less, have a high viscosity and form an emulsion during the manufacturing process, resulting in a large amount of water being mixed into the product. There was a problem. For this reason, methods using additives such as glycols, alcohols, aldehydes, ketones, or ethers have been disclosed (the same publication and Japanese Patent Application Laid-Open No. 61-225282). This additive has the effect of lowering the viscosity of rare earth soaps and can prevent water from entering the product. However, when this type of soap is stored for a long period of time, it becomes micelles, and a portion of the soap may settle and separate.

[Problems to be Solved by the Invention] As a result of intensive research to solve the above problems, the present inventor found that when the amount of organic acid relative to the rare earth element is increased,
We have discovered that it is possible to produce a rare earth soap solution that does not cause soap to settle and separate over a long period of time, can lower its viscosity without adding any of the additives mentioned above, and has almost no water in it. The present invention has been made based on this knowledge, and an object of the present invention is to provide a rare earth soap solvent having a novel composition that does not cause soap to settle and separate even after long-term storage, and which can have an extremely low water content. Our objective is to provide this manufacturing method. [Means for Solving the Problems] That is, the present invention provides the following: In a rare earth soap solution in which a rare earth soap is dissolved in an organic solvent, the number of acid equivalents of the organic acid relative to the number of rare earth atoms is 3.
A rare earth soap solution and a rare earth salt aqueous solution consisting of 2 or more and an alkali soap aqueous solution of an organic acid containing an organic acid with an acid equivalent number of 3.2 or more relative to the number of rare earth atoms in the aqueous solution in the presence of an organic solvent. This is a method for producing a rare earth soap solution, which is characterized by carrying out a double decomposition reaction. Examples of the organic acids include fatty acids, alicyclic carboxylic acids, aromatic carboxylic acids, etc.
In order to be easy to handle, it is preferable to use an organic acid with a not very high molecular weight, and an organic acid with a carbon number of 6 to 1°4, especially 8 to 1.
2 fatty acids or alicyclic carboxylic acids are preferred. In the case of fatty acids, either straight chain or branched fatty acids can be used. Both saturated carboxylic acids and unsaturated carboxylic acids can be used, but saturated carboxylic acids are more preferred. Specifically, for example, cabrylic acid, 2-octylic acid, 2-
Ethylhexylic acid, pelargonic acid, cabric acid, lauric acid, naphthenic acid, methylcyclohexanoic acid, methylcyclohexenoic acid, cyclohebutanoic acid, etc. can be used. On the other hand, examples of rare earth elements include cerium, neodymium, lanthanum, praseodymium, samarium, promethium, eurobium, gadolinium, terbium, dysbrosium, holmium, erbium, thulium, ytterbium, and lutetium. , lanthanum, and praseodymium are preferred. These rare earth elements may be used alone or in combination of two or more. In particular, mixed rare earth soaps containing two or more of cerium, neodymium, lanthanum, and praseodymium are suitable for the purpose of the present invention. 1
One mole corresponds to one acid equivalent, and in the case of an organic acid having two hydroxyl groups, one mole corresponds to two acid equivalents. Since rare earths are trivalent, stoichiometrically, the number of acid equivalents to the number of rare earth atoms is 3.0, and if a rare earth soap is an organic acid with one carboxyl group, it has 3 moles bonded to it. It turns out. On the other hand, in the present invention, the organic acid has an acid equivalent number of 3.2 or more relative to the number of rare earth atoms, and the organic acid is contained in a stoichiometric ratio or more. If the acid equivalent number is less than 3.2, there is a disadvantage that water and emulsion form during the manufacturing process, resulting in a large amount of water being mixed into the product.To solve this problem, ketones, alcohols, etc. When additives are added, problems such as micellization and sediment formation occur during storage, but the rare earth soap of the present invention was able to solve these problems all at once. In order to improve the above-mentioned drawbacks, it is preferable that the amount of this organic acid is as large as possible with respect to the rare earth, but on the other hand, if the amount is too large, it is not preferable because it will only unnecessarily lower the metal concentration of the rare earth soap. For this reason, the organic acid is selected in the range of 3.2 to 9.6, more preferably 3.3 to 6.6, particularly preferably 3.3 to 4.0 in acid equivalent number relative to the number of rare earth atoms. It is better. In addition, this rare earth soap is in the form of a solution dissolved in an organic solvent, and the organic solvent in this case may include aliphatic, alicyclic, aromatic hydrocarbons, or a mixture thereof.
For example, naphtha, petroleum ether, white spirit,
Mineral turpentine, kerosene, diesel oil, hexane, hebutane,
Octane, nonane, decane, dodecane, tetradecane,
Cyclohexane, cyclohebutane, cyclepenkune, cyclooctane, cyclohexene, benzene, toluene,
Generally widely used organic solvents such as xylene and ethylbenzene can be used. In particular, from the viewpoint of handling, those with a high flash point are preferred, and from the viewpoint of solubility, those that are aromatic-rich are preferred. In addition, it is preferable for the concentration of the rare earth soap to be dissolved in the organic solvent to be as high as possible for handling purposes, but the solubility differs depending on the type of organic solvent and the type of rare earth, so the concentration of the rare earth soap dissolved in the organic solvent should be determined as appropriate, taking into account this solubility and the intended use. However, when used as a fuel additive or paint drying agent, the concentration of the rare earth element may be adjusted to a range of 1 to 7% by weight. Generally, if it is less than 1% by weight, the amount added to the fuel will be large, making transportation and addition work complicated, and if it is more than 7% by weight, fluidity will decrease, making it difficult to add or adjust the amount added. This is not very desirable as it may result in The rare earth soap solution of the present invention can be prepared by directly reacting fine pieces of rare earth metal with a heated organic acid, by reacting a salt of a rare earth element with the organic acid, or by preparing an alkali soap solution of the organic acid from an aqueous solution of a rare earth salt. It can be obtained by a method of precipitation, etc., but a method of manufacturing using an alkaline soap is preferred because it causes less contamination of impurities. That is, in the present invention regarding the production of rare earth soap solution,
First, an aqueous alkali hydroxide solution, such as an aqueous solution of sodium hydroxide or potassium hydroxide, with a concentration below the solubility is added to the above organic acid, and the mixture is heated at a temperature of 40 to 90°C.
Stir for a minute to obtain an aqueous solution of alkaline soap. Next, an aqueous solution having a concentration below the solubility of the rare earth salt, such as chloride or sulfate, is added to this aqueous solution in such an amount that the organic acid has an acid equivalent number of 3 to 2 or more relative to the number of atoms of the rare earth. At the same time, add an amount of organic solvent such that the element content is 1 to 7% by weight, allow metathesis reaction at a temperature of 40 to 90°C for 20 to 60 minutes, and separate the organic layer from the aqueous layer to obtain a rare earth soap solution. be able to. In addition, when producing rare earth soap consisting of two or more kinds of rare earths, each individual rare earth salt may be mixed and used, but so-called mixed rare earth salts, which are a mixture of salts before being separated into each element, may be used. It is especially preferable to use soil or concentrated diluted materials because they are inexpensive. The above rare earth soap solution is used as a fuel accelerator or paint drying agent, but in this case, the soap contains 10 to 500% of the rare earth element relative to the fuel oil or paint.
It is appropriately selected and added within the range of 0 ppm. [Example] Jyo & Sho 1 2756 g of a 5% by weight aqueous sodium hydroxide solution was added to 524 g of 2-ethylhexylic acid, and the mixture was heated at about 75°C for 30
The mixture was heated and stirred for a minute to obtain an aqueous sodium 2-ethylhexylate solution. To this sodium 2-ethylhexylate aqueous solution, 2698 g of a mixed rare earth chloride aqueous solution with a concentration of 5% by weight as a rare earth element having a ratio of cerium 48: neodymium 2 liters: lanthanum 23 and 2490 ml light oil were simultaneously added.
A double decomposition reaction was carried out at a temperature of 5°C for 30 minutes with stirring, and the organic layer was separated by standing. Add 1.2 times the amount of 7 to this organic layer.
A 2-ethylhexylic acid rare earth soap solution having an acid equivalent of 3.20 was obtained by adding 5° C. warm water and stirring and washing. This solution was centrifuged at a rotation speed of 300 rpm for 20 minutes, and the water content and sedimented solid content were measured. Also, add this solution to 30
After being left for one day, centrifugation was performed at a rotation speed of 3000 rpm for 20 minutes to measure the amount of sedimented solids. The results are shown in Table 1 together with the number of acid equivalents relative to the number of rare earth atoms in the organic acid. 12-3 1-3 Various 2-ethylhexylic acid rare earth soap solutions having different numbers of acid equivalents relative to the number of rare earth atoms were prepared in the same manner as in Example 1 except that the amount of 2-ethylhexylic acid was changed,
In the same manner as in Example 1, the amount of moisture, the amount of settled solids, and their changes over time were measured. These results are also listed in Table 1. As is clear from the results of the above Examples and Comparative Examples, the rare earth soap solution of the present invention in which the acid equivalent of the organic acid is 3.20 or more has little water contamination even when no additives are used, and immediately after production. Of course, even after long-term storage, solid content is produced in small amounts. Tsuji Comparative Example 1 During the metathesis reaction in Comparative Example 2 above, 1Ovol% of n-hexyl alcohol was added as a solubilizer to the light oil at the same time as the light oil, and the same operation as in Comparative Example 2 was carried out.
A caprylic acid rare earth soap solution containing a solubilizer was obtained. The physical properties of this solution were measured in the same manner. These results are also shown in Table 1. Comparative Example In Comparative Example 4, instead of n-hexyl alcohol, 10 vol% ethyl cellosolve was added to light oil,
A similar operation was performed. These results are also listed in Table 1. In Comparative Examples 4 and 5 above, by adding a solubilizer, it was possible to suppress the incorporation of water and the formation of solid content immediately after production, but when stored for a long time, the formation of solid content due to sedimentation and separation of soap. Admitted. Margin below [Effects of the Invention] The rare earth soap solution of the present invention has an acid equivalent number of 3.2 or more with respect to the number of rare earth atoms in the organic acid, so the soap does not sediment and separate even when stored for a long period of time. Since it has the special effect of extremely reducing the water content without using additives such as alcohol, it is useful as a combustion improver for fuel oil, a paint drying agent, and the like.

Claims (1)

[Scope of Claims] 1. A rare earth soap solution in which a rare earth soap is dissolved in an organic solvent, and the number of acid equivalents of an organic acid to the number of rare earth atoms is 3.2 or more. 2. The rare earth soap solution according to claim 1, wherein the rare earth is a mixture containing two or more of cerium, neodymium, lanthanum, or praseodymium. 3. A rare earth salt aqueous solution and an alkali soap aqueous solution of an organic acid containing an organic acid having an acid equivalent number of 3.2 or more relative to the number of rare earth atoms in the aqueous solution are subjected to a metathesis reaction in the presence of an organic solvent. A method for producing a rare earth soap solution.