JPH11322771A - Production of zinc dithiophosphate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing in a high yield and purity zinc dithiophosphate free from offensive odor such as hydrogen sulfide odor and copper plate corrosiveness and excellent in storage stability and lubricity. SOLUTION: This method for producing zinc dithiophosphate comprises the following two processes: (1) a dithiophosphoric acid is prepared by reaction between (A) a Cn alcohol or phenol and (B) pentaphosphorus disulfide, and (2) the reaction between the dithiophosphoric acid and (C) zinc oxide is conducted; wherein the acid value (Av: mgKOH/g) of the dithiophosphoric acid to be used in the 2nd process is characterized by satisfying the relationship: 1,400<=Av(n+4.6) <=2,000.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing zinc dithiophosphate.

[0002]

2. Description of the Related Art In recent years, high performance and high output of automobiles and various industrial machines have been advanced. Along with this, the performance required for lubricating oils used for them has also been advanced. In particular, from the background of environmental problems and resource saving, there is a strong demand for a long drain that can lengthen the lubricating oil refining period. Various additives are blended in these lubricating oils. Among them, there is a great demand for load-bearing additives, detergents / dispersants, viscosity index improvers, antioxidants, pour point depressants and the like. Therefore, in order to improve the performance of the lubricating oil, it is necessary to improve the performance of each of these additives. Under these circumstances, zinc dithiophosphate, which has antioxidant properties, corrosion inhibitory properties and abrasion resistance, is widely used as a multifunctional additive. There is a need for improved performance.

[0003] Usually, zinc dithiophosphate is produced by neutralizing dihydrocarbon-substituted dithiophosphoric acid obtained from phosphorus pentasulfide and alcohol with zinc oxide. For example, Japanese Patent Publication No. 48-37251 discloses that dihydrophosphoric acid-substituted dithiophosphoric acid and zinc oxide obtained by removing water generated by blowing an inert gas into a small amount of zinc nitrate,
There is described a method of obtaining zinc dithiophosphate by reacting in the presence of a zinc salt selected from zinc chloride and zinc sulfate. JP-A-47-32005 discloses that dithiophosphoric acid produced from alcohols and phosphorus pentasulfide is dissolved in an aqueous alkali metal solution such as sodium hydroxide and the like, and a zinc salt such as zinc chloride is added thereto to form a basic compound. Methods for obtaining zinc dithiophosphate are described. Also, U.S. Pat.
No. 6,243, discloses a dihydrocarbyl-substituted dithiophosphoric acid and a basic zinc selected from zinc oxide, zinc hydroxide and zinc carbonate in a closed system in the presence of water and heptane to produce zinc dithiophosphate. Are described.

[0004]

However, in the conventional method for producing zinc dithiophosphate represented by the above, the purity of the final product and the performance when used as a lubricant greatly vary depending on the production conditions. Had a problem. In particular, it was not possible to obtain a product having excellent lubricity in high purity and high yield without having an odor such as hydrogen sulfide odor or a copper plate corrosiveness in the final product.

[0005] The inventors of the present invention have conducted intensive studies and found that the acid value of dithiophosphoric acid reacted with zinc oxide depends on the yield, purity and performance of the final product zinc dithiophosphate when used as a lubricant. It was discovered that it had a significant effect, and the present invention was reached. Accordingly, an object of the present invention is to provide a production method capable of obtaining zinc dithiophosphate having high storage stability and lubricity in high purity and high yield without any unpleasant odor such as hydrogen sulfide odor or copper plate corrosiveness. Is to provide.

[0006]

That is, the present invention comprises, as a first step, a step of producing (A) an alcohol or phenol having n carbon atoms and (B) phosphorus pentasulfide to produce dithiophosphoric acid; In the method for producing zinc dithiophosphate having a step of reacting the dithiophosphoric acid produced in the first step and zinc oxide (C) as a step, the acid value of the dithiophosphoric acid used in the second step Av (mg KOH
/ G)

(Equation 2) In which zinc dithiophosphate is produced. or,
The present invention is a lubricating oil or grease composition containing zinc dithiophosphate produced by the above method.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION R ¹ and R ^{2 in} the general formula (1) are determined by (A) the alcohol or phenol having n carbon atoms used in the first step of the production method of the present invention. Examples of the alcohol or phenol that can be used include various alcohols or phenols having a straight, branched, saturated, unsaturated, aliphatic, alicyclic, or aromatic carbon chain. (A) Even if the alcohol or phenol having n carbon atoms is one kind,
Two or more types may be used in combination. When two or more alcohols or phenols are used in combination, the carbon number n is an average value.

Examples of the alcohol include methanol, ethanol, propanol, 2-propanol, butanol, pentanol, 2-methyl-4-pentanol, hexanol, heptanol, octanol, 2-
Ethylhexanol, nonanol, 1-decanol, isodecyl alcohol, 2-methyldecanol, lauryl alcohol, 1-tridecanol, isotridecyl alcohol, myristyl alcohol, cetyl alcohol, palmityl alcohol, stearyl alcohol, behenyl alcohol, eicosanol (C ₂₀ ), docosanol (C _22), tetracosanol (C _24), hexacosanol (C _26), octacosanol (C _28), myricyl alcohol, Lasse roll, tetra triacontanol, allyl alcohol, oleyl alcohol, isostearyl Alcohol, cyclopentanol, cyclohexanol, 2-butyloctanol, 2-butyldecanol,
2-hexyloctanol, 2-hexyldecanol,
2-hexyldecanol, 2-octyldecanol,
2-octyldodecanol, 2-octyltetradecanol, 2-decyldodecanol, 2-decyltetradecanol, 2-decylhexadecanol, 2-dodecyltetradecanol, 2-dodecylhexadecanol, 2-
Dodecyl octadecanol, 2-tetradecyl octadecanol, 2-tetradecyl icosanol, 2-hexadecyl octadecanol, 2-hexadecyl icosanol and the like can be mentioned.

Examples of the phenol include phenol, cresol, ethyl phenol, tert-butyl phenol, octyl phenol, nonyl phenol,
Dodecylphenol, styrenated phenol, paracumylphenol, benzylphenol and the like can be mentioned.

In particular, when zinc dithiophosphate produced by the production method of the present invention is used as a lubricant,
From the viewpoint of oil solubility and lubricity, 1-decanol, isodecyl alcohol, 2-methyldecanol, lauryl alcohol, 1-tridecanol, isotridecyl alcohol,
Alcohols having 10 to 18 carbon atoms such as myristyl alcohol, cetyl alcohol, palmityl alcohol, stearyl alcohol and oleyl alcohol are preferred, and lauryl alcohol, 1-tridecanol and myristyl alcohol are more preferred.

In the production method of the present invention, as the first step, the above-mentioned (A) alcohol or phenol having n carbon atoms is reacted with (B) phosphorus pentasulfide to produce dithiophosphoric acid. This reaction generates dithiophosphoric acid and produces hydrogen sulfide as a by-product according to the following reaction formula (a).

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The reaction conditions are not particularly limited. Usually, while blowing nitrogen gas from the liquid bottom and at normal pressure, the temperature is preferably the melting point of the (A) alcohol or phenol having n carbon atoms used, which is more preferably from 200 ° C. to 200 ° C. Is 60 to 160
C., most preferably at 80 to 140.degree. C. for 3 to 12 hours to obtain dithiophosphoric acid while by-producing hydrogen sulfide. The resulting dithiophosphoric acid is usually
It is a colorless to dark green oily liquid.

[0013] The dithiophosphoric acid obtained in the above first step is acidic. Accordingly, the acid value can be measured by performing a neutralization titration with an aqueous alkali hydroxide solution using a phenolphthalein indicator in a suitable organic solvent such as 2-propanol. In the production method of the present invention, the acid value (Av: mgKOH / g) of dithiophosphoric acid produced in the first step and used in the second step is as follows:

(Equation 3) Must be in the range. Here, n is the carbon number of the alcohol or phenol (A). Furthermore, preferably

(Equation 4) Range, most preferably

(Equation 5) It is good to be in the range. The acid value is 1,400 / (n +
If dithiophosphoric acid is used in an amount less than 4.6), not only the yield of zinc dithiophosphate, which is the final product, will decrease, but it will be difficult to separate by-products, and as a result, the purity of zinc dithiophosphate will decrease. .

In the second step of the production method of the present invention, the above dithiophosphoric acid having a specific acid value is reacted with zinc oxide (C). This reaction generally produces zinc dithiophosphate and by-produces water according to the following reaction formula (b).

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In order for the above reaction to proceed efficiently, dithiophosphoric acid is preferably added in an amount of 1.0 mol per 1 mol of zinc oxide.
〜2.0 mol, more preferably 1.1-1.9 mol, most preferably 1.2-1.8 mol. There are no particular restrictions on the choice of zinc oxide to be used, but from the viewpoint of reaction activity and filterability, the specific surface area is 4 to 5 m.
It is preferable to use zinc oxide having a particle size of ² / g and an average particle size of 0.4 to 0.5 μm.

The reaction conditions in the second step are not particularly limited, but are usually at normal pressure and the temperature is preferably 20 to 120.
° C, more preferably 40-100 ° C, most preferably 6 ° C.
By reacting at 0 to 80 ° C for 3 to 12 hours, zinc dithiophosphate, which is the object of the production method of the present invention, can be obtained. In the second step, a reaction accelerator such as water and zinc nitrate can be added. The by-produced water may be distilled off under reduced pressure, and unreacted solids such as zinc oxide may be removed by filtration. The zinc dithiophosphate obtained by the production method of the present invention is usually liquid or solid at normal temperature.

According to the production method of the present invention, in addition to the zinc dithiophosphate neutral salt represented by the following general formula (1),

Embedded image The following components are called basic and overbased salts:

[0018]

Embedded image

Embedded image This component is formed according to the following reaction formula when water is present in the reaction system:

Embedded image

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The basic salt and the overbased salt are components having excellent lubricity, and are not impurities in producing zinc dithiophosphate. Therefore, the zinc dithiophosphates of the general formulas (1) to (3) do not need to be separated into a single component:

Embedded image

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Further, as is apparent from the above formula, the presence of zinc ions and hydroxide ions affects the formation of basic salts and overbased salts, so that by-product water is immediately removed during the reaction. No need. In addition, if water is appropriately added in the second step, it is possible to control the formation ratio of the generated basic salt and overbased salt.

According to the production method of the present invention, zinc dithiophosphate can be obtained with higher purity and higher yield than the conventional production method. In addition, since the amount of by-products is small, zinc dithiophosphate having no unpleasant odor such as hydrogen sulfide odor or copper plate corrosiveness and excellent storage stability can be obtained. In particular, the production method of the present invention is effective in that it is not restricted by the chain length or structure of the alcohol or phenol used. Further, the zinc dithiophosphate produced by the production method of the present invention is excellent in lubricity and antioxidant properties because it has high purity and few by-products.

The zinc dithiophosphate obtained by the production method of the present invention is excellent and useful as a lubricant, and in particular, has excellent friction reducing ability and antioxidant ability. When the zinc dithiophosphate obtained by the production method of the present invention is used as a lubricant additive, it is preferably 0.01 to 5% by weight, more preferably 0.05 to 5% by weight based on the lubricant base oil.
To 1% by weight, more preferably 0.1 to 0.5% by weight. When used as a grease additive, it is preferably added in an amount of 0.1 to 10% by weight, more preferably 0.5 to 7% by weight, and still more preferably 1 to 5% by weight, based on the base grease. The lubricating base oil that can be used may be any of mineral oil, synthetic oil or a mixture thereof. The kinematic viscosity of the lubricating base oil is not particularly limited, but is preferably 1 to 50 cSt at 100 ° C and 10 to 1 at 40 ° C.
000 cSt, and the viscosity index (VI) is preferably 70
The number is more preferably 100 or more.

Mineral oil is separated from natural crude oil, and is produced by appropriately distilling, refining, and the like.
Main component of mineral oil is hydrocarbon (mostly paraffins)
And further contains a naphthene component, an aromatic component, and the like. Base oils which have been subjected to hydrorefining, solvent dewaxing, solvent extraction, solvent dewaxing, hydrogen dewaxing, catalytic dewaxing, hydrocracking, alkali distillation, sulfuric acid washing, clay treatment, etc. are also preferably used. be able to.

The synthetic oil is a chemically synthesized lubricating oil, for example, poly-α-olefin, polyisobutylene (polybutene), diester, polyol ester, phosphate ester, silicate ester, polyalkylene. Glycols, polyphenyl ethers, silicones, fluorinated compounds, alkylbenzenes and the like can be mentioned. Among them, poly-α-olefin, polyisobutylene (polybutene), diester, polyol ester, polyalkylene glycol, and the like can be used for general purposes, and can be preferably used for internal combustion engine oil, processing oil, and the like.

When used as a grease, zinc dithiophosphate is added to a base grease obtained by adding a thickener to a base oil composed of mineral oil or synthetic oil. As the thickener, for example, a soap-based or complex soap-based thickener,
Examples include terephthalate-based thickeners, urea-based thickeners, organic non-soap-based thickeners such as polytetrafluoroethylene and fluorinated ethylene-propylene copolymer, and inorganic non-soap-based thickeners.

The zinc dithiophosphate produced by the production method of the present invention can be used in combination with other lubricating oil additives as required. Representative lubricating oil additives include, for example, oiliness agents, friction modifiers, extreme pressure agents, antioxidants, detergents, dispersants, viscosity index improvers, defoamers, rust inhibitors, pour point depressants And the like. Among them, sulfurized oxymolybdenum dithiophosphate and oxymolybdenum dithiocarbamate are excellent in antioxidant ability and friction reducing ability, and can be preferably used in combination with zinc dithiophosphate obtained by the production method of the present invention.

The zinc dithiophosphate produced by the production method of the present invention can be added to lubricating oils for various uses. For example, industrial lubricating oil, turbine oil, machine oil,
Bearing oil, compressor oil, hydraulic oil, hydraulic oil, internal combustion engine oil, refrigeration oil, gear oil, oil for automatic transmission, transaxle fluid, metalworking oil, various greases, and the like. Among them, it is suitable as an antioxidant for internal combustion engine oils such as vehicle engines, two-cycle engines, aircraft engines, marine engines, and locomotive engines. Examples of the internal combustion engine include a gasoline engine, a diesel engine, a jet engine, a gas turbine engine, an alcohol engine, and the like.

[0027]

EXAMPLES The present invention will be described more specifically with reference to the following examples. In the following examples, parts and percentages are by weight unless otherwise specified. <Example 1> (Production of di-1-octyldithiophosphoric acid) A stirring rod, a stirring seal, a thermometer, a Dimroth reflux cooling tube and a nitrogen introducing tube were attached to a flask connected to a hydrogen sulfide absorbing caustic soda water trap bottle. 521 g of 1-octanol (4.
0 mol) and then 222 g (1.0 mol) of phosphorus pentasulfide under ice-cooling. The mixture was heated to 100 to 110 ° C. while paying attention to foaming due to generation of hydrogen sulfide, reacted for 5 hours while blowing nitrogen, and then cooled. A calculated amount of hydrogen sulfide was generated, giving 694 g (1.96 mol) of dark green di-1-octyldithiophosphoric acid. This was dissolved in 2-propanol adjusted to neutrality in advance, and neutralized and titrated with a phenolphthalein indicator and an aqueous solution of potassium hydroxide. As a result, the acid value was 148 mgKOH / g.

(Production of zinc di-1-octyldithiophosphate) To 355 g (1.0 mol) of di-1-octyldithiophosphoric acid produced by the above reaction was added 40.7 g of zinc oxide.
(0.5 mol) and reacted at normal pressure for 2 hours at 60-80 ° C. while paying attention to the heat generated during the reaction. Subsequently, the pressure was reduced, and dehydration was performed at 100 to 110 ° C. and 10 Torr or less for 1 hour. This was filtered using diatomaceous earth as a filter aid to obtain 375 g of zinc di-1-octyldithiophosphate as a yellow liquid. The yield regarded as a neutral salt was 97%, the ratio of the neutral salt was 72%, and the purity was 95% by ³¹ P-NMR analysis.
As a result of elemental analysis, the powder contained 8.4% of zinc, 16.8% of sulfur, and 7.9% of phosphorus. Kinematic viscosity at 40 ° C is 80m
m ² / sec.

[0029] <Example 2> - (the dilauryl / myristyl / manufacture of cetyl mixed dithiophosphoric acid) same reaction apparatus as in Example 1, lauryl / myristyl / cetyl alcohol mixture (C ₁₂ min 75%, n = 1
2.7, hydroxyl value 291 mg KOH / g) 771 g (4.
0 mol) was charged with 222 g (1.0 mol) of phosphorus pentasulfide. While paying attention to the heat generated by the reaction,
The mixture was heated to 0 ° C., reacted for 5 hours while blowing nitrogen, and then cooled. Theoretical amount of hydrogen sulfide is generated and a dark green di-lauryl / myristyl / cetyl mixed dithiophosphoric acid 94
0 g (1.96 mol) were obtained. As a result of the neutralization titration, the acid value was 113 mgKOH / g.

(Production of mixed di-lauryl / myristyl / cetyl zinc dithiophosphate) Di-lauryl / myristyl / cetyl mixed dithiophosphate 4 prepared by the above reaction
80 g (1.0 mol) was charged with 42.7 g (0.53 mol) of zinc oxide, and reacted and treated in the same manner as in Example 1.
496 g of yellow liquid di-lauryl / myristyl / cetyl mixed zinc dithiophosphate were obtained. The yield regarded as a neutral salt was 97%. According to ³¹ P-NMR analysis, the ratio of the neutral salt was 77%.
% And purity was 93%. As a result of elemental analysis, zinc 6.
It contained 0%, 12.2% sulfur and 6.2% phosphorus.

<Example 3> (Production of di-1-octyldithiophosphoric acid) In a reactor similar to that in Example 1, 521 g (4.0 mol) of 1-octanol was added to 222 g (1.0 mol) of phosphorus pentasulfide. )
The mixture was reacted at 110 to 120 ° C. for 5 hours while blowing nitrogen, and then cooled. Calculated amount of hydrogen sulfide is generated and di-1
694 g (1.96 mol) of -octyldithiophosphoric acid were obtained. As a result of the neutralization titration, the acid value was 116 mgKOH / g.

(Production of zinc di-1-dioctyldithiophosphate) To 355 g (1.0 mol) of dioctyldithiophosphoric acid produced by the above reaction was added 40.7 g (0.4 mol) of zinc oxide.
5 mol), and the reaction and treatment were carried out in the same manner as in Example 1 to obtain a yellow liquid of zinc di-1-octyldithiophosphate 37
5 g were obtained. 96% yield as neutral salt, ³¹ PN
According to MR analysis, the ratio of the neutral salt was 75%, and the purity was 93%. Elemental analysis revealed that zinc was 8.1% and sulfur was 16.3.
%, 8.0% phosphorus.

<Example 4> (Production of dilauryl dithiophosphoric acid) Lauryl alcohol (C ₁₂ min. 98% or more) 7 was reacted in the same reactor as in Example 1.
To 45 g (4.0 mol) were charged 222 g (1.0 mol) of phosphorus pentadisulfide, and 120 to 130 ° C. while blowing nitrogen.
, And then cooled. The calculated amount of hydrogen sulfide is generated and 915 g of dark green dilauryl dithiophosphoric acid
(1.96 mol). As a result of the neutralization titration, the acid value is 10
It was 5 mgKOH / g.

(Production of zinc dilauryl dithiophosphate)
70.7 g (1.0 mol) to 40.7 g (0.5 mol) of zinc oxide
And the reaction and treatment were carried out in the same manner as in Example 1 to obtain 478 g of zinc dilauryl dithiophosphate as a yellow liquid. The yield, which was regarded as a neutral salt, was 96%, the ratio of the neutral salt was 77%, and the purity was 95% by ³¹ P-NMR analysis. As a result of elemental analysis, 7.1% of zinc, 13.3% of sulfur, and 6.5% of phosphorus
Was included. The kinematic viscosity at 40 ° C. is 140 mm ² /
Seconds.

Comparative Example 1 355 g (1.0 mol) of di-1-octyldithiophosphoric acid having an acid value of 57 mgKOH / g was reacted with zinc oxide and treated in the same manner as in Example 1. And the filterability of the final product was very poor.
The yield was 232 g, and the yield regarded as a neutral salt was 60%. In addition, the product had a strong mercaptan-like odor.
^{By 31} P-NMR analysis, in addition to zinc dialkyldithiophosphate, peaks derived from many by-products were observed,
The purity was as low as 70%. As a result of elemental analysis, zinc 5.0
%, 14.8% sulfur, and 7.7% phosphorus, indicating a reduction in zinc content.

Comparative Example 2 Using 480 g (1.0 mol) of a mixed di-lauryl / myristyl / cetyl dithiophosphoric acid having an acid value of 70 mg KOH / g, the mixture was reacted with zinc oxide and treated in the same manner as in Example 2. The filtration of the final product was very poor. The yield was 359 g, and the yield regarded as a neutral salt was 70%. In addition, the product had a strong hydrogen sulfide-like odor. ^{By 31} P-NMR analysis, peaks derived from many by-products were recognized in addition to the zinc dialkyldithiophosphate, and the purity was as low as 75%. As a result of elemental analysis, it contained 3.5% of zinc, 11.1% of sulfur, and 6.0% of phosphorus, and a decrease in zinc content was observed.

<Comparative Example 3> Using 467 g (1.0 mol) of dilauryldithiophosphoric acid having an acid value of 54 mgKOH / g, the reaction was carried out by reacting with zinc oxide in the same manner as in Example 4. The filterability of the material was very poor. The yield was 349 g, and the yield regarded as a neutral salt was 70%. In addition, the product had a strong hydrogen sulfide-like odor. ³¹ P-NM
By R analysis, peaks derived from many by-products were recognized in addition to the zinc dialkyldithiophosphate, and the purity was 80%.
% Was low. As a result of elemental analysis, 4.7% of zinc and 1 of sulfur
It contained 1.9% and phosphorus 6.4%, indicating a decrease in zinc content.

<Example 5> (Production of distearyl dithiophosphoric acid) Stearyl alcohol ( _C18 min. 95% or more) instead of 1-octanol
The reaction was carried out in the same manner as in Example 1 except that 1,082 g (4.0 mol) was used, and 1,270 distearyldithiophosphoric acid was used.
g (2.0 mol) were obtained. As a result of the neutralization titration, the acid value was 85.
mg KOH / g.

(Production of zinc distearyl dithiophosphate)
To 635 g (1.0 mol) of distearyl dithiophosphoric acid produced by the above reaction, 48.8 g (0.6 mol) of zinc oxide was added.
Mol), and the reaction and treatment were carried out in the same manner as in Example 1 to obtain zinc distearyldithiophosphate 64 having a melting point of about 50 ° C.
0 g was obtained. 96% yield as neutral salt, ³¹ PN
According to MR analysis, the ratio of the neutral salt was 76%, and the purity was 98%. As a result of elemental analysis, zinc 5.3%, sulfur 9.7%,
It contained 4.7% phosphorus.

Example 6 Production of bis (dodecylphenyl) dithiophosphoric acid
1,050 g of dodecylphenol instead of octanol
(4.0 mol), and the reaction was conducted in the same manner as in Example 1 to obtain 1,23 bis (dodecylphenyl) dithiophosphoric acid.
8 g (2.0 mol) were obtained. As a result of the neutralization titration, the acid value was 8
It was 8 mgKOH / g.

[Production of zinc bis (dodecylphenyl) dithiophosphate] 619 g (1.0 mol) of bis (dodecylphenyl) dithiophosphoric acid produced by the above reaction was added to
48.8 g (0.6 mol) of zinc oxide was charged, and 80 to 90
The reaction was carried out at normal pressure for 10 hours. Subsequently, the solution was heated under reduced pressure and then heated to 120 to 130 ° C. and dehydrated at 10 Torr or less for 3 hours, and then filtered using diatomaceous earth as a filter aid to obtain 618 g of zinc bis (dodecylphenyl) dithiophosphate. The yield regarded as a neutral salt was 95%, the ratio of the neutral salt was 90%, and the purity was 98% by ³¹ P-NMR analysis.
As a result of elemental analysis, zinc was 5.2%, sulfur was 9.5%, and phosphorus was 4.5%.
6%.

<Use Example 1> Zinc dithiophosphate obtained in Examples 1 to 6, zinc dithiophosphate obtained in Comparative Examples 1 to 3, and commercially available zinc dithiophosphate manufactured from isobutanol and 2-ethylhexanol (Commercial item 1) (C ₄ ~
The following tests were carried out for C ₈ ZDTP) and a commercially available zinc bis (dodecylphenyl) dithiophosphate (commercially available product 2) (C ₁₂ φZDTP). Table 1 shows the results.

(Test 1) Copper plate corrosion test JIS-K-2513 without diluting each zinc dithiophosphate
Was subjected to a copper plate corrosion test. However, the test condition is temperature 150
° C and the test time was 1 hour. (Test 2) Load resistance test Each zinc dithiophosphate was subjected to a high-speed four-ball friction tester without dilution, and the seizure load was measured. The test conditions were a rotation speed of 1,500 rpm, a test time of 1 minute, and a test temperature of room temperature. (Test 3) Oxidation stability test 1 part by weight of each zinc dithiophosphate was dissolved in 99 parts of 100N refined paraffin mineral oil, and an oxidization stability test (ISOT) of JIS-K-2514 was performed. The test conditions were 16
At 5.5 ° C., the test time was 24 hours.

[0044]

[Table 1]

<Use Example 2> Kinematic viscosity at 100 ° C. is 1
A base grease obtained by mixing an aliphatic amine-based urea thickener with a paraffin-based refined mineral oil of 5 mm ² / sec, and uniformly dispersing the mixture at 25 ° C. so as to have a mixing consistency of 287,
3% of each of the above zinc dithiophosphates was added and kneaded to prepare samples.

(Test 1) An SRV reciprocating friction tester manufactured by Optimol, Germany was used. Plate (made of SUJ-2 steel, φ
24 × 7.85mm) on a ball (made of SUJ-2 steel, φ10
mm), load 200N, temperature 50 ° C, amplitude 1
It was reciprocated for 2 hours at 50 Hz and a cycle of 50 Hz, and the friction coefficient after 2 hours was measured. (Test 2) Using a high-speed four-ball testing machine, the friction coefficient and the wear scar diameter were measured. The test conditions were 1,800 rpm,
The load was 40 kg, the temperature was 40 ° C., and the test time was 1 hour.

[0047]

[Table 2]

[0048]

The effect of the present invention is to provide a novel method for producing zinc dithiophosphate. When dithiophosphoric acid having a specific acid value is used according to the present invention, zinc dithiophosphate can be produced with high purity and high yield. The zinc dithiophosphate produced according to the present invention has high purity and is not corrosive, and thus can be preferably used as a lubricant.

Continued on the front page (72) Inventor Isao Miyashita Asahi Denka Kako Kogyo Co., Ltd., 7-2-35 Higashiogu, Arakawa-ku, Tokyo (72) Inventor Kazutoshi Morita 7-35, Higashiogu, Arakawa-ku, Tokyo Asahi Denka Industrial Co., Ltd.

Claims (4)

[Claims] 1. a first step of producing dithiophosphoric acid by reacting (A) an alcohol or phenol having n carbon atoms and (B) phosphorus pentasulfide to produce dithiophosphoric acid;
Reacting the dithiophosphoric acid produced in the first step with zinc oxide (C); wherein the acid value of the dithiophosphoric acid used in the second step (Av: mgKOH / g) ) Is A process for producing zinc dithiophosphate. 2. Zinc dithiophosphate is represented by the following general formulas (1) to (3): (In the formula, R ¹ and R ² represent a hydrocarbon group.) (In the formula, R ¹ and R ² have the same meanings as described above.) The method for producing zinc dithiophosphate according to claim 1, wherein the compound is one or a mixture of two or more compounds represented by the formula (wherein, R ¹ and R ² have the same meanings as described above). 3. A lubricating oil composition containing zinc dithiophosphate produced by the production method according to claim 1. 4. A grease composition containing zinc dithiophosphate produced by the production method according to claim 1.