JPH04161496A - Production of perbasic alkaline earth metal salt - Google Patents

Abstract

PURPOSE:To obtain the title slat having excellent performances as additive for lubricant and inexpensive manufacturing cost by neutralizing a specific alkyl group-containing hydroxybenzoic acid with an alkaline earth metal compound and then subjecting the neutralized substance to perbasic salt forming treatment. CONSTITUTION:(A) alkyl group-containing hydrobenzoic acid containing inorganic acids such as acid or hydrochloric acid having >=70mol% (preferably 80-85mol%) purity is neutralized with (B) an alkaline earth metal compound preferably comprising calcium oxide or calcium hydroxide, having >=100 mesh particle diameter and subjected to perbasic salt forming treatment to give a perbasic alkaline earth metal salt.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for producing an overbased alkaline earth metal salt, and more specifically, an alkyl group that has excellent performance as an additive for lubricants and is inexpensive to produce. The present invention relates to a method for producing an overbased alkaline earth metal salt of hydroxybenzoic acid.

[Problems to be solved by conventional technology and inventions] Modern automobiles have been equipped with reduction catalysts such as three-way catalysts to counteract exhaust gases, and as a result, emphasis has been placed on high-speed running and high output, and internal combustion Engines are being operated more harshly.

On the other hand, with the aim of improving combustion from the perspective of energy conservation,
BACKGROUND OF THE INVENTION As automobile bodies are becoming lighter, crankcases are also becoming smaller, and the amount of crankcase oil (internal combustion engine oil) is also decreasing. As a result, the amount of heat added per unit amount of oil is increasing, and oil temperature increases significantly with high-speed driving and high output, and there is a strong tendency for high oil temperatures to persist for a long time. For this reason, various additives are added to the lubricant base oil in an effort to improve the performance of the lubricant. In particular, additives have become useful to prevent lack of cleanliness due to lack of heat resistance and to prevent emulsification when water is mixed into lubricating oil. Among these additives, detergent dispersants are commonly used in lubricants for various internal combustion engines, and their importance as lubricants has become particularly high.

Conventional detergents and dispersants are mainly oil-soluble metal salts, such as basic alkyl salicylate additives whose main component is a polyvalent metal salt of alkyl salicylic acid (Japanese Patent Publication No. 48-3).
5325, British Patent No. 795,657, and British Patent No. 786,167).

Examples of the method for producing the above-mentioned basic alkyl salicylate additive include the following methods (1) to (2).

■After reacting alkylphenol with an alkali metal compound, it is carboxylated by reacting with carbon dioxide gas, and then hydrolyzed with mineral acid to obtain alkylsalicylic acid.After converting the alkylsalicylic acid into an alkali metal salt, a polyvalent metal chloride is obtained. Method for obtaining basic alkyl salicylate additives by metathesis using
(See Japanese Patent Publication No. 48-35325, etc.).

■A method of reacting the alkyl salicylic acid obtained by the above hydrolysis with a polyvalent metal compound (British Patent No. 786167)
(Refer to the publication number, etc.)

■A method of reacting an alkyl salicylic acid obtained by alkylating salicylic acid with a polyvalent metal compound (Japanese Patent Publication No. 48-3532
(See Publication No. 5, etc.)

However, as detailed in JP-A-60-101196, unreacted alkylphenol and its metal salts reduce thermal stability, so purification treatments such as water washing and extraction of alkylsalicylic acid are required. In addition, complicated operations such as converting unreacted alkylphenol into a derivative by sulfurizing, sulfonating, or condensing the unreacted alkylphenol with aldehyde have been required.

Therefore, the present inventors solved the problems of the above-mentioned conventional method for producing basic alkyl salicylate additives, and developed alkyl group-containing hydroxybenzoic acid, which is inexpensive to produce and is useful as an additive for lubricants. We conducted extensive research to develop a method for producing overbased alkaline earth metal salts.

[Means to solve the problem]

As a result, alkyl group-containing hydroxybenzoic acid with a purity of 70 mol% or more, obtained by separating and removing the aqueous layer in the reaction product hydrolyzed with an inorganic acid (mineral acid), was used as a raw material, and the inorganic acid contained was It has been found that the above problems can be solved by neutralizing with a compound. The present invention was completed based on this knowledge. That is, the present invention provides an overbased hydroxybenzoic acid containing an inorganic acid and a purity of 70 mol% or more, which is characterized by neutralizing it with an alkaline earth metal compound and then subjecting it to an overbased salting treatment. A method for producing an alkaline earth metal salt is provided.

In the method of the present invention, an alkyl group-containing hydroxybenzoic acid having a purity of 70 mol % or more and containing substantially an inorganic acid as an impurity is used as a raw material. The raw materials used in the method of the present invention can, of course, be of high purity, but they can also be used even if they contain a considerable amount of impurities. As a guideline for its purity, it should be as low as 70 mol%, but 80 to 85 mol% is preferable in consideration of economic efficiency and practicality.As a result, purification such as water washing and extraction as post-treatment Since no processing is required, it can be manufactured at low cost.

The alkyl group-containing hydroxybenzoic acid has various types, but usually has 8 to 36 carbon atoms, preferably 1
It has at least one, preferably 1 to 2 alkyl groups of 2 to 24, more preferably 14 to 18. Furthermore, due to the positional relationship between the hydroxyl group and the carboxyl group in the alkyl group-containing hydroxybenzoic acid, o +
, m-, and p-, but as the alkyl group-containing hydroxybenzoic acid used in the present invention, 0-
Those containing a large amount of salicylate having substitution positions are preferred.

Note that the inorganic acid (mineral acid) contained in the alkyl group-containing hydroxybenzoic acid, which is the raw material, is the acid used in the process of preparing the alkyl group-containing hydroxybenzoic acid, and is usually sulfuric acid, hydrochloric acid, etc. It is.

Although there are various methods for producing an alkyl group-containing hydroxybenzoic acid containing an inorganic acid and having a purity of 70 mol% or more, it is generally produced by the following method.

First, a raw material alkylphenol containing at least one alkyl group, preferably one or two alkyl groups, is reacted with an alkali metal salt hydroxide to form a metal salt, and then carbon dioxide is blown into the alkylphenol to carboxylate it. The number of carbon atoms in the alkyl group is generally 8 to 36, preferably 12 to 24,
More preferably, it is 14-18. For alkyl groups with carbon atoms of 7 or less, the obtained overbased alkaline earth metal salt of hydroxybenzoic acid containing an alkyl group has good compatibility with lubricant additives used together and oil solubility with lubricant base oil. There is a disadvantage that it is inferior. Furthermore, those having an alkyl group having 37 or more carbon atoms have the disadvantage that the base value of the salt decreases.

Furthermore, various alkylphenols can be used as the alkylphenol, such as monoalkylphenol, dialkylphenol, or a mixture thereof, but usually the monoalkylphenol content is 80% by weight or more, preferably 90% by weight or more. belongs to.

Moreover, the alkali metal hydroxide used here is preferably sodium hydroxide or potassium hydroxide.

The operation in this process is, for example, by adding an alkali metal hydroxide to alkylphenol heated to 60 to 80°C, and bubbling inert gas (nitrogen, argon, etc.).
The alkylphenol is heated to 60"C or higher, preferably 190 to 200°C, to convert the alkylphenol into a metal phenoxylate and remove by-product water. This reaction can be carried out without a solvent, but mineral oil or aromatic oil can be used as a diluent. A group solvent may also be used.Then, this metal phenoxide is heated under pressure (5 to 15 kg/
Carboxylation is carried out under the action of carbon dioxide (1 to 3 hours) at 140 to 180 degrees Celsius (cm2). Among the products in this reaction are unreacted alkylphenols.

It contains a metal salt of alkylphenol and an alkali metal salt of hydroxybenzoic acid containing an alkyl group. The yield of the alkali metal salt of the alkyl group-containing hydroxybenzoic acid at this time is preferably 80 to 85 mol%.

Next, the obtained product is cooled to room temperature to 60°C, and an inorganic acid (30% sulfuric acid or hydrochloric acid) is added to adjust the pH to 2 to 3 acidic. If the acidity is not adjusted here, problems such as the subsequent separation treatment not being carried out well or metal salts of alkylphenol remaining will occur. 1 at room temperature to 60°C
After reacting for ~2 hours, the aqueous layer is separated off. In order to perform this separation completely, it is preferable to dilute with an aromatic hydrocarbon such as toluene or xylene. The purpose of the present invention can be achieved if the purity of the alkyl group-containing hydroxybenzoic acid in the hydrolyzate thus obtained is 70 mol% or more, but if the purity is less than 70 mol%, the purity of the alkyl group-containing hydroxybenzoic acid can be achieved. This is not preferred because the performance of the overbased alkaline earth metal salt, ie, thermal stability, cleaning dispersibility, and demulsifying property, is significantly reduced.

The present invention involves neutralizing the alkyl group-containing hydroxybenzoic acid containing an inorganic acid and having a purity of 70 mol% or more with an alkaline earth metal compound, and then subjecting it to an overbased salting treatment. This is a method for producing an overbased alkaline earth metal salt.

The neutralization treatment in the method of the present invention involves reacting the hydrolyzate obtained above (i.e., alkyl group-containing hydroxybenzoic acid containing an inorganic acid) with an alkaline earth metal compound to form a salt. .

For example, an alkaline earth metal compound is added to a solution of the alkyl group-containing hydroxybenzoic acid containing the inorganic acid obtained above diluted with a solvent such as an aromatic hydrocarbon at room temperature to 60°C. A method for neutralizing the remaining inorganic acid and alkyl group-containing hydroxybenzoic acid is mentioned.

In addition, in the overbased salting treatment after the neutralization treatment in the method of the present invention, an alkaline earth metal compound is added in a stoichiometrically excess amount as a metal salt, and a solvent and carbon dioxide are added and heated. Then, it is reacted with the above-mentioned neutralized product. For example, to the product obtained by the neutralization treatment of the present invention, an alkaline earth metal compound, alcohol (preferably methanol) as a solvent, and water are added, carbon dioxide is blown into the product, and then heated to 120 to 160°C and alcohol is added. After removing water and water, the pressure was reduced to remove the aromatic hydrocarbons used as a diluent in the neutralization treatment, and the mixture was heated at 120 to 160°C for 1 to 4 hours.
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The alkaline earth metal compounds used in the above neutralization treatment and overbased chlorination treatment may be the same or different, and are, for example, alkaline earth metal oxides or hydroxides, preferably calcium.

These are oxides or hydroxides of barium, magnesium, etc. A more preferable example of this compound is calcium oxide or calcium hydroxide, and its particle size is not particularly limited, but it is 100 mesh or more, especially 10
It is desirable that the 0 mesh sieve residue is 0.1% by weight or less. This is because if the mesh size is less than 100, it is assumed that there is a high probability of the presence of impurities.

〔Example〕

Next, the present invention will be explained in more detail with reference to production examples, examples, and comparative examples. However, the present invention is not limited to these Examples.

Production Example 1 80 g of 48% sodium hydroxide was added to 318 g of alkylphenol having 16 carbon atoms, and 200 ml/nitrogen was added.
After bubbling at min., the mixture was heated at 190 to 200°C for 2 hours to remove by-product water. The obtained metal phenoxide was cooled to 140°C, nitrogen was stopped, and carbon dioxide was constantly supplied at 8 kg.
/cm" and held for 1 hour to perform carboxylation. The product was cooled to 80°C, depressurized, and 220g of xylene was added to prepare a xylene solution. This solution was Cooled to °C, 199 g of 30% sulfuric acid
was added over 30 minutes, reacted for 1 hour, and the aqueous layer was separated and removed. The pH value of the aqueous layer at this time was 2.

The results of structural analysis of the obtained product by C1Cl2-N and 'H-NMR are as follows.

〇 unitary (55%), p unitary (15%), 〇-unit (15%), alkylphenol (15
%) [R in the formula is an alkyl group having 16 carbon atoms] The purity of the alkyl group-containing hydroxybenzoic acid in the product is 85 mol%
Met.

Example I Calcium hydroxide (JI
S special issue) 20.9g was added and stirred for 30 minutes to neutralize the remaining sulfuric acid.

31 g of calcium hydroxide (100 mesh sieve residue 3.8%) to 307 g of the product obtained.

After adding 70 g of methanol and 11 g of water and stirring at room temperature for 30 minutes, 11.1 g of carbon dioxide was blown into the mixture over 30 minutes. Next, methanol and water were removed by heating to 140°C, and xylene was further removed by reducing the pressure.
It was kept at 0°C for 1 hour. After adding 100 g of xylene and filtration, 119 g of paraffinic mineral oil was added to remove the xylene, and the overbased alkaline earth metal salt 340
I got g.

The kinematic viscosity of the obtained product was 31.29 cSt (100°
C), the base value was 169 mgKOH/g (perchloric acid method), and the calcium content was 5.8% by weight.

Example 2 Calcium hydroxide (100 mesh sieve residue 0.1%
The same operation as in Example 1 was performed except that 31 g of the following) was used. As a result, 340 g of an overbased alkaline earth metal salt product was obtained.

The kinematic viscosity of the obtained product was 32.92 cSt (100°
C), base value is 170 mgKOH/g (perchloric acid method).

The calcium content was 5.8% by weight.

Comparative Example 1 C16 alkylphenol 9 was added to the product of Production Example 1.
7.8 g was added to adjust the purity of the alkyl group-containing hydroxybenzoic acid to 65 mol %, and 60 g of xylene was added thereto. Calcium hydroxide (JIS special number) was added to the xylene solution of this alkyl group-containing hydroxybenzoic acid at 40°C.
20.9 g was added and stirred for 30 minutes to neutralize the remaining sulfuric acid. 51 g of calcium hydroxide (100 mesh sieve residue 3.8%), 74 g of methanol, and 11 g of water were added to 307 g of the obtained product, and after stirring at room temperature for 30 minutes, 14.4 g of carbon dioxide was used. , in the same manner as in Example 1. As a result, 344 g of an overbased alkaline earth metal salt was obtained.

The kinematic viscosity of the obtained product was 34.20 cSt (I Q
OoC), base number 172 mgKOH/g (perchloric acid method).

The calcium content was 6.1% by weight.

In addition to those obtained in Example 1.2 and Comparative Example 1 above, a commercially available basic alkyl salicylate additive (base number 16
5 mgKOH/g, calcium 5.7% by weight, and kinematic viscosity 29.01 cSt (100°C) as Comparative Example 2, and a performance test was conducted under the following conditions. The results are shown in Table 1.

The test oil used in this test was 81.5% by weight of paraffinic mineral oil, 18.5% by weight of each lubricant additive, and 0.0% antifoaming agent. A mixture containing 4% by weight of OO was used. The properties of each sample oil are shown in Table 2.

(Panel coker test) Fed 791B Method 3462 (1969
), panel temperature 300°C1 oil temperature 160.3
It was done under the time constraints.

(Hot tube test) Sample oil 0.3 ml/hr in a glass tube with an inner diameter of 2 mm
, .

Air 10ml/mjn, glass tube temperature 320°C
The water was kept flowing for 16 hours while maintaining the temperature. A score was given by comparing the lacquer deposited in the glass tube with a color sample (10 points for transparent, 0 points for black).

(Demulsifying property test) It was conducted in accordance with JISK2520.

(Oxidation stability test) A continuous test was conducted at 165.5°C for 172 hours in accordance with JISK2514.

(The following is a blank space) [Effects of the Invention] As described above, the method of the present invention is an excellent method for producing an overbased alkaline earth metal salt with excellent lubricity and low production cost, and its practical use is The value is high.

In addition, the overbased alkaline earth metal salt produced by the method of the present invention can be used as a lubricant additive for various internal combustion engines (gasoline engines, diesel engines, gas engines, etc.), as well as various additives or reagents. Widely and effectively used.

Patent applicant: Idemitsu Kosan Co., Ltd. Agent Patent Attorney Tamotsu Otani

Claims (3)

[Claims] (1) An overbased alkaline earth characterized by neutralizing an alkyl group-containing hydroxybenzoic acid containing an inorganic acid and having a purity of 70 mol% or more with an alkaline earth metal compound and then subjecting it to an overbased chlorination treatment. Method for producing similar metal salts. (2) The method for producing an overbased alkaline earth metal salt according to claim 1, wherein the alkaline earth metal compound is calcium oxide or calcium hydroxide. (3) The method for producing an overbased alkaline earth metal salt according to claim 1, wherein the alkaline earth metal compound has a particle size of 100 mesh or more.