JPH0641561A - Fluoroalkylsuccinic diester and its production and magnetic recording medium bearing the same - Google Patents

Abstract

PURPOSE:To provide a new compound excellent in lubricity even under circumstances of low to high humidity, useful for magnetic recording media, etc. CONSTITUTION:The compound of formula I (R1 is an aliphatic alkyl or aliphatic alkenyl; R2 and R3 are such that one of them is a fluoroalkyl ether, the other being a fluoroalkyl, fluoroalkenyl, fluorophenyl, aliphatic alkyl or aliphatic alkenyl), e.g. a compound of formula II. The compound of the formula I can be obtained by addition reaction between (A) an aliphatic alkyl succinic anhydride or aliphatic alkenyl succinic anhydride and (B) a fluoroalkyl ether group- bearing alcohol in the presence of an acid catalyst to form a monoester, which is then esterified with either fluoroalkyl group-bearing alcohol, fluoroalkenyl group-bearing alcohol, fluorophenyl group-bearing alcohol, aliphatic alkyl alcohol or aliphatic alkenyl alcohol in the presence of an acid catalyst.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel fluorine-containing compound useful as a precision machine, a lubricant for precision parts, a surfactant, a release agent, an anticorrosive agent, etc., which requires high-precision lubricity. The present invention relates to a manufacturing method and a magnetic recording medium having the same.

[0002]

2. Description of the Related Art With the miniaturization and high precision of mechanical devices and parts, the lubrication mode of their sliding parts has been shifting from fluid lubrication to boundary lubrication. In particular, in electronic equipment such as VTRs and magnetic disks, and electronic parts, the use of a ferromagnetic metal thin film for the purpose of improving the recording density ensures high-precision lubrication for sliding between the magnetic tape or magnetic disk and the magnetic head. It has become necessary. For example, in the case of vapor-deposited tapes and hard disks, there are only a few lubricant layers on the magnetic layer surface in order to minimize the spacing loss between the magnetic recording medium and the magnetic head while achieving high output while ensuring durability and reliability. It is formed to have a thickness of 10Å. Therefore, development of an organic compound having excellent lubricity has become an important issue as a material for forming the lubricant layer.

As a lubricant for a metal thin film type magnetic recording medium, a fluoroalkyl ether group-containing monocarboxylic acid represented by the chemical formula 2 has excellent compatibility with a metal thin film.
Many proposals have been made (for example, JP-A-58-41).
438, JP-A-59-127230, JP-A-62-58414).

[0004]

[Chemical 2]

As a recent conventional example, there is a perfluoropolyether ester of monocarboxylic acid represented by the chemical formula 3 (Japanese Patent Laid-Open No. 2-49218).

[0006]

[Chemical 3]

[0007]

However, the lubricant of the monocarboxylic acid having a fluoroalkyl ether group represented by the above (Chemical formula 2) or the perfluoropolyether ester of the monocarboxylic acid represented by the (Chemical formula 3) is lubricated. The agent has a problem that the lubricity is deteriorated in an environment of high humidity.

The present invention solves the above-mentioned conventional problems, and an object thereof is to provide a substance which does not deteriorate in lubricity even in an environment of low humidity to high humidity.

[0009]

The substance of the present invention for achieving the above object is a fluorine-containing alkyl succinic acid diester represented by the general formula (Formula 4).

[0010]

[Chemical 4]

The aliphatic alkyl group or the aliphatic alkenyl group (R ₁ ) has 6 to 30, preferably 10 carbon atoms.
-24 are suitable, and if the carbon number is less than 6 or more than 30, the lubricity decreases. Fluoroalkyl ether group (R
₂ or R ₃ ) has 5 to 5 carbon atoms bonded to fluorine.
0, preferably 8 to 30, is suitable, and if the carbon number is less than 5 or exceeds 50, the lubricity decreases. A fluoroalkyl group, a fluoroalkenyl group, a fluorophenyl group, an aliphatic alkyl group, and an aliphatic alkenyl group (R ₂ or R ₃ ) suitably have a carbon number of 30 or less, preferably 20 or less. If it exceeds the limit, lubricity decreases.

In the magnetic recording medium of the present invention, a ferromagnetic film is provided on a non-magnetic support, and a fluorine-containing alkyl compound represented by the general formula (Chem. 4) is directly formed on the ferromagnetic film or through a protective film. A lubricant layer containing one or more succinic acid diesters is provided.

In this lubricant layer, the fluorine-containing alkyl succinic acid diester represented by the general formula (Formula 4) is used alone or in the form of a thin layer by adding other lubricants, rust preventives and the like. A suitable amount thereof is in the range of 0.05 to 100 mg, preferably 0.1 to 50 mg per 1 m ² of the surface. As the other lubricant and rust preventive, a fluorine-containing compound is preferable, and a liquid type fluorine-containing compound is more preferable. The suitable amount of addition is 0 to 80%, preferably 0 to 70%. If the content of the fluorine-containing alkyl succinic acid diester represented by the general formula (Formula 4) is less than 20%, the effect of the present invention is difficult to obtain.

As the protective film, a carbon thin film obtained by a method such as sputtering or plasma CVD in an amorphous form, a graphite form, a diamond form or a mixed state or a laminated state thereof can be applied, and the thickness thereof is 5
0 to 500Å is preferable.

[0015]

The fluorine-containing alkyl succinic acid diester of the present invention has one fluoroalkyl ether end group and two aliphatic hydrocarbon end groups, that is, an aliphatic alkyl end group or an aliphatic alkenyl end group in the same molecule. Structure or structure having one fluoroalkyl ether end group and one fluorocarbon end group in the same molecule, that is, a fluoroalkyl end group or a fluoroalkenyl end group or a fluorophenyl end group and an aliphatic hydrocarbon end group Is. Here, the fluoroalkyl ether group and the fluorocarbon group are exposed on the surface of the metal thin film, the surface of the protective film, or the surface of the magnetic head to contribute to lowering the energy of the surface and form a non-adhesive surface. As a result, the fluoroalkyl ether group and the fluorocarbon group exert a protective effect on the surface of the metal thin film and the surface of the magnetic head under a low humidity environment, but this effect is stronger in the fluoroalkyl ether group than in the fluorocarbon group. However, since the fluoroalkyl ether group has a large number of hydrophilic ether bonds in its molecule, it has a property of absorbing water in a high humidity environment. On the other hand, since the fluorocarbon group and the aliphatic hydrocarbon group are hydrophobic, the hydrophilicity of the fluoroalkyl ether group can be masked by allowing them to exist in the same molecule as the fluoroalkyl ether group.
In order to make this masking effect effective, it is necessary that the fluorocarbon group and the aliphatic hydrocarbon group be present at the ends of the molecule and have a molecular structure that wraps the fluoroalkyl ether group from both sides. By the way, the aliphatic hydrocarbon group is a flexible carbon-carbon bond chain, and exhibits good lubricity because it is oriented by an appropriate intermolecular interaction with a hydrocarbon chain of another adjacent molecule.

Therefore, the presence of each of these terminal groups in a well-balanced manner exhibits excellent lubricity in all environments from a low humidity environment to a high humidity environment due to their synergistic effect.

[0017]

【Example】

(Embodiment 1) Hereinafter, the first embodiment of the present invention will be specifically described.

The chemical formula of the substance of this embodiment is represented by (Chemical Formula 5).

[0019]

[Chemical 5]

The above substance will be explained in comparison with the general formula of (Chemical Formula 4). As the aliphatic alkyl group R ₁ , C ₁₈ H ₃₇
(Octadecyl), R ₂ has a fluoroalkenyl group having 6 carbons bonded to fluorine, and R ₃ has a fluoroalkyl ether group having 20 carbons bonded to fluorine.

Next, a method for producing the substance represented by Chemical formula 5 will be described. Starting materials were octadecyl succinic anhydride 35.3 g (0.10 mol) represented by (Chemical Formula 6) and (Chemical Formula 7).
Fluoroalkyl ether group-containing alcohol 11
It is 4.6 g (0.10 mol).

[0022]

[Chemical 6]

[0023]

[Chemical 7]

The above raw material, 4.5 g of paratoluenesulfonic acid (hereinafter abbreviated as PTS) as an acid catalyst (3% based on the weight of the raw material) and 500 ml of normal heptane were collected in a 1 liter flask equipped with a stirring blade. Then, the reaction was carried out under reflux for 24 hours. After completion of the reaction, the reaction solution was repeatedly washed with distilled water until the pH reached 7, and then dried over anhydrous sodium sulfate. Next, normal heptane was distilled off, the reaction mixture was dissolved in benzene, and cooled to -10 ° C to remove unreacted octadecyl succinic anhydride. Further, the reaction mixture was treated with a methanol solution in the same manner to remove unreacted fluoroalkyl ether group-containing alcohol to obtain 102 g of the monoester of (Chemical Formula 8).

[0025]

[Chemical 8]

Next, 75.0 g (0.
05 mol) and PTS 1.4 g (1.5% by weight of raw material)
%), 300 ml of benzene, and 20.9 g (0.05 mol) of a fluoroalkenyl group-containing alcohol represented by the chemical formula 9 in a 1 liter flask equipped with a water separator and a stirring blade,
The reaction was carried out under reflux for 24 hours.

[0027]

[Chemical 9]

After completion of the reaction, the reaction solution was adjusted to pH 7 with distilled water.
It was repeatedly washed until it became, and dried over anhydrous sodium sulfate. Next, benzene was distilled off, the reaction mixture was dissolved in methanol and cooled to -10 ° C to remove unreacted monoester. Further, the reaction mixture was treated with isopropyl alcohol (IPA) in the same manner,
Unreacted fluoroalkyl ether group-containing alcohol was removed to obtain 68 g of a colorless transparent liquid. This colorless and transparent liquid was analyzed by infrared spectroscopy (IR), gel permeation chromatography (GPC) and organic mass spectrometry (FD-M).
From S), it was found that the substance does not contain reaction raw materials and byproducts and is a substance represented by the formula (Formula 5).

IR: Absorption peak at 1,775 cm ^-1 of acid anhydride, disappearance of absorption peak of 3,330 cm ^-1 of alcohol, appearance of absorption peak of 1,760 cm ^-1 of ester.

GPC: Alcohol with fluoroalkyl ether group, alcohol with fluoroalkenyl group, octadecyl succinic anhydride and monoester Not detected.

FD-MS; major peak at m / e 1,899. In this example, octadecyl succinic anhydride was used as the aliphatic alkyl succinic anhydride, but an aliphatic alkenyl succinic anhydride may be used instead of octadecyl succinic anhydride to produce the same. Further, as the substance to be reacted with the monoester, a fluoroalkyl group-containing alcohol, a fluorophenyl group-containing alcohol, an aliphatic alkyl alcohol, or an aliphatic alkenyl alcohol may be used in place of the fluoroalkenyl group-containing alcohol.

Further, in this embodiment, normal heptane was used for the monoesterification and benzene was used for the diesterification as the reaction solvent, but the reaction raw material and the monoester were dissolved,
Reaction temperature is 40 to 150 ° C, preferably 60 to 120 ° C
Any hydrophobic solvent other than alcohols and esters can be used. As the acid catalyst, those commonly used for esterification, for example, mineral acids such as sulfuric acid and hydrochloric acid, organic acids such as aromatic sulfonic acid, and Lewis acids such as boron fluoride etherate can be applied.

This is the same in the other embodiments. (Embodiment 2) Next, a second embodiment of the present invention will be specifically described.

The substance of this example is the same as that of (Example 1) and is different in the manufacturing method. The starting materials used in this example were 35.3 g (0.10 mol) of octadecyl succinic anhydride represented by (Chemical formula 6) and 41.8 g (0.1% of an alcohol with a fluoroalkenyl group represented by (Chemical formula 9).
0 mol). The above raw materials and 300 ml of benzene were collected in a 1 liter. Flask equipped with a stirring blade, and the mixture was refluxed for 24 hours.
A time reaction was performed. After completion of the reaction, benzene was distilled off from the reaction solution, and the reaction mixture was mixed with isopropyl ether (IP
It was dissolved in E) and cooled to -10 ° C to remove unreacted octadecyl succinic anhydride. Further, the reaction mixture was treated with a methanol solution in the same manner to remove the unreacted fluoroalkenyl group-containing alcohol to obtain 54 g of the monoester of (Chemical Formula 10).

[0035]

[Chemical 10]

Next, 38.5 g (0.
05 mol) and PTS 2.9 g (3.0% by weight of raw material)
%) And 300 ml of normal heptane and 57.3 g of a fluoroalkyl ether group-containing alcohol represented by the chemical formula (7).
(0.05 mol) and 1 lit. equipped with a water separator and a stirring blade.
It was collected in a flask of and the reaction was carried out under reflux for 24 hours. After completion of the reaction, the reaction solution was repeatedly washed with distilled water until the pH reached 7, and then dried over anhydrous sodium sulfate. Then, normal heptane was distilled off, the reaction mixture was dissolved in methanol, and cooled to -10 ° C to remove unreacted monoester. Further, the reaction mixture was treated with isopropyl alcohol (IPA) in the same manner,
Unreacted fluoroalkyl ether group-containing alcohol was removed to obtain 65 g of a colorless transparent liquid. This colorless and transparent liquid was a substance represented by the same formula (Formula 5) as in (Example 1).

(Embodiment 3) Next, a third embodiment of the present invention will be specifically described.

The substance of this Example is the same as that of (Example 1) and is different in the manufacturing method. The starting materials for this example are: 35.3 g (0.10 mol) of octadecyl succinic anhydride represented by (Chemical formula 6) and 114.6 g of a fluoroalkyl ether group-containing alcohol represented by (Chemical formula 7).
(0.10 mol). PTS of the above raw materials and acid catalyst
4.5 g (3% based on the weight of the raw material) and 500 ml of normal heptane were collected in a 1 liter flask equipped with a stirring blade, and reacted under reflux for 24 hours. After the reaction,
The same purification treatment as in (Example 1) was carried out to obtain 102 g of the monoester of (Chemical formula 8). 75.0 g of this monoester
(0.05 mol) and thionyl chloride (60 g) were collected in a 1 lit. flask equipped with a stirring blade and reacted under reflux for 3 hours. After completion of the reaction, excess thionyl chloride was removed from the reaction solution by distillation under reduced pressure, and then 20.9 g of a fluoroalkenyl group-containing alcohol represented by Chemical formula 9 under ice cooling.
A mixed solution of 20 ml of pyridine (0.05 mol) and 300 ml of IPE was added dropwise over 2 hours. After the dropping is completed,
The reaction was completed by continuing stirring at room temperature for 4 hours. After completion of the reaction, the reaction solution was washed with 300 ml of a 5% hydrochloric acid aqueous solution to remove excess pyridine from the reaction solution. Further, this solution was repeatedly washed with distilled water until the pH reached 7, and then dried over anhydrous sodium sulfate. Next, IPE was distilled off, the reaction mixture was dissolved in methanol, and cooled to -10 ° C to remove unreacted monoester. Further, the reaction mixture was treated with IPA solution in the same manner to remove unreacted fluoroalkyl ether group-containing alcohol to obtain 72 g of a colorless transparent liquid. This colorless and transparent liquid was a substance represented by the same formula (Formula 5) as in (Example 1).

The production method of this example is characterized in that after the monoester is produced, it is chlorinated to give a chlorinated carboxylic acid, and then the diester is produced in the presence of a base catalyst. According to this method, the monoester is produced. The yield when the diester is produced is 90% or more. On the other hand, it is about 70% in the direct production methods of (Example 1) and 2.

As the chlorinating agent, inorganic halogen compounds such as phosphoryl chloride, thionyl chloride, phosphorus pentachloride and phosphorus trichloride can be applied. Further, pyridine as a base catalyst,
Triethylamine, zinc chloride, iodine, etc. can be applied.

In this example, the fluoroalkyl ether group-containing alcohol was used when the aliphatic alkyl succinic acid was monoesterified, and the fluoroalkenyl group-containing alcohol was used when the diester was formed. However, the order may be reversed. You get the same.

(Embodiment 4) Next, an embodiment of the magnetic recording medium of the present invention will be specifically described.

In the non-magnetic support of the magnetic recording medium of this example, there were several granular projections (average height 70 Å, diameter 1 μm) with 100 μm ^{2 on the} surface due to silica fine particles added in the polyester film. Moreover, on the surface of the polyester film where the comparatively large projections due to the fine particles due to the polymerization catalyst residue are reduced as much as possible, the silica colloid particles with a diameter of 150Å are used as the core, and the steep mountain-like projections using the ultraviolet curing epoxy resin as the binder Was used to form 1 × 10 ⁷ pieces per 1 mm ² . Then, a Co—Ni ferromagnetic film (Ni content 20%, film thickness 10
00Å) in the presence of a trace amount of oxygen. The oxygen content in the ferromagnetic film was 5% in atomic fraction.

Next, on the above-mentioned ferromagnetic film, 10 mg of fluorine-containing alkyl succinic acid diester of Chemical formula 5 was added per 1 m ^2.
Was applied to form a lubricant layer and then cut into a predetermined width to produce a magnetic tape. The magnetic tape was hung on a commercially available VCR in an environment of 23 ° C., 10% RH, 40 ° C. and 80% RH, and the output characteristics during repeated running were measured, and the RF output decreased by 3 dB from the initial value, or The number of runs until the start of output fluctuation was calculated.

(Example 5) In the magnetic tape of (Example 4), a magnetic tape using (Chemical formula 11) instead of (Chemical formula 5) was prepared and the same test was conducted.

[0046]

[Chemical 11]

(Example 6) In the magnetic tape of (Example 4), instead of (Chemical formula 5), (Chemical formula 5) and a known lubricant C _{7 were used.}
A similar test was carried out by making a magnetic tape using a mixture of F ₁₅ C ₂ H ₄ NHC ₁₄ H ₂₉ in a weight ratio of 2: 1.

(Example 7) In the magnetic tape of (Example 4), instead of (Chemical formula 5), (Chemical formula 11) and a known lubricant C were used.
_A similar test was carried out by making a magnetic tape using a mixture of ₁₇ H ₃₅ COOC ₂ H ₄ C ₈ F ₁₇ in a weight ratio of 1: 1.

The test results of the above examples are shown in (Table 1). Lubricants of (Conventional Example 1), (Conventional Example 2) and (Conventional Example 3) in the table are shown in (Chemical Formula 12), (Chemical Formula 13) and (Chemical Formula 14), respectively.

[0050]

[Chemical 12]

[0051]

[Chemical 13]

[0052]

[Chemical 14]

[0053]

[Table 1]

From Table 1, all the magnetic tape samples provided with the lubricant layer containing one or more fluorine-containing alkyl succinic acid diesters of the present invention are excellent in the number of repeated runnings in low humidity and high humidity. It is clear.
On the other hand, it is clear that the conventional magnetic tape provided with a lubricant layer consisting of only a lubricant has poor running durability in low humidity or high humidity.

(Embodiment 8) Next, an embodiment of another magnetic recording medium of the present invention will be specifically described.

The non-magnetic support of the magnetic recording medium of the present example was formed by applying a non-magnetic Ni-P alloy plating of 25 μm thickness on the surface of an Al alloy plate having a diameter of 95 mm and a thickness of 1.2 mm, and averaging by texturing. A protrusion having a roughness of 50Å and a maximum height of 300Å was used. 1300Å Cr with a thickness of 1300Å by sputtering on non-magnetic Ni-P alloy plating
Form a 600 Å thick Co-Ni ferromagnetic film on the base,
Further, a sample A is formed by forming a graphite protective film having a thickness of 200Å on the ferromagnetic film by a sputtering method. Sample B is formed by forming a diamond-like carbon protective film having a thickness of 50Å by the plasma CVD method instead of the graphite protective film. Next, the fluorine-containing alkyl succinic acid diester represented by Chemical formula 5 was applied on the protective films of these samples so that the amount thereof was 10 mg per 1 m ² , and a lubricant layer was provided to prepare a magnetic disk. The magnetic disk is at 23 ° C, 10% RH and 40
A CSS (contact start stop) test was conducted in an environment of ℃ and 80% RH, and the number of CSSs at the time when the friction coefficient exceeded 1.0 or C at the time of head crash
The durability was judged by the number of SSs.

(Example 9) In the magnetic disk of (Example 8), a magnetic disk using (Chemical Formula 11) in place of (Chemical Formula 5) was prepared and the same test was conducted.

(Example 10) In the magnetic disk of (Example 8), a magnetic disk using the same lubricant as in (Example 6) in place of (Chemical formula 5) was prepared and the same test was conducted.

(Example 11) In the magnetic disk of (Example 8), a magnetic disk using the same lubricant as in (Example 7) in place of (Chemical formula 5) was prepared and the same test was conducted.

The test results of the above examples are shown in (Table 2). Lubricants of (Conventional example 4), (Conventional example 5) and (Conventional example 6) in the table are shown in (Chemical formula 12), (Chemical formula 13) and (Chemical formula 14), respectively.

[0061]

[Table 2]

From Table 2, all the magnetic disks provided with the lubricant layer containing one or more fluorine-containing alkyl succinic acid diesters of the present invention are excellent in CSS durability in low humidity and high humidity. It is clear. On the other hand, it is clear that the conventional magnetic disk provided with a lubricant layer made of only a lubricant has poor CSS durability in low humidity or high humidity.

In the embodiment, (Chemical formula 5) and (Chemical formula 1)
The substance of 1) was explained, but (Chemical formula 15) and (Chemical formula 1)
Similar effects can be obtained with the substances of (6), (Chemical formula 17), (Chemical formula 18) and (Chemical formula 19).

[0064]

[Chemical 15]

[0065]

[Chemical 16]

[0066]

[Chemical 17]

[0067]

[Chemical 18]

[0068]

[Chemical 19]

[0069]

As is apparent from the above description, the fluorine-containing alkyl succinic acid diester of the present invention has one fluoroalkyl ether end group and two aliphatic hydrocarbon end groups, that is, fatty acid, in the same molecule. A structure having a group alkyl end group or an aliphatic alkenyl end group or one fluoroalkyl ether end group and one fluorocarbon end group in the same molecule, that is, a fluoroalkyl end group, a fluoroalkenyl end group or a fluorophenyl end group 1
Due to the structure having individual aliphatic hydrocarbon end groups, it exhibits an excellent effect that the lubricity does not deteriorate even in an environment of low humidity to high humidity.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location G11B 5/71 7215-5D // C07B 61/00 300 C10N 40:14

Claims (6)

[Claims] 1. The general formula is A fluorine-containing alkyl succinic acid diester represented by: 2. A ferromagnetic film is provided on a non-magnetic support, and a fluorine-containing alkyl succinic acid diester represented by the general formula (Chemical Formula 1) is formed on the ferromagnetic film directly or through a protective film. A magnetic recording medium provided with a lubricant layer containing at least one kind. 3. An aliphatic alkyl succinic anhydride or an alkenyl succinic anhydride and an alcohol having a fluoroalkyl ether group are subjected to an addition reaction in the presence of an acid catalyst to give a monoester, which monoester and an alcohol having a fluoroalkyl group. A method for producing a fluorine-containing alkyl succinic acid diester, which comprises esterifying any of a fluoroalkenyl-containing alcohol, a fluorophenyl-containing alcohol, an aliphatic alkyl alcohol, and an aliphatic alkenyl alcohol in the presence of an acid catalyst to form a diester. 4. An aliphatic alkyl succinic anhydride or an aliphatic alkenyl succinic anhydride and an alcohol with a fluoroalkyl group, an alcohol with a fluoroalkenyl group, an alcohol with a fluorophenyl group, an aliphatic alkyl alcohol or an aliphatic alkenyl alcohol. A method for producing a fluorine-containing alkyl succinic acid diester, wherein an addition reaction is performed to obtain a monoester, and the monoester and a fluoroalkyl ether group-containing alcohol are subjected to an esterification reaction in the presence of an acid catalyst to give a diester. 5. An aliphatic alkyl succinic anhydride or an alkenyl succinic anhydride and an alcohol having a fluoroalkyl ether group are subjected to an addition reaction in the presence of an acid catalyst to give a monoester, and the monoester is chlorinated and chlorinated. A carboxylic acid is prepared by reacting the chlorinated carboxylic acid with any of a fluoroalkyl group-containing alcohol, a fluoroalkenyl group-containing alcohol, a fluorophenyl group-containing alcohol, an aliphatic alkyl alcohol and an aliphatic alkenyl alcohol in the presence of a base catalyst. A method for producing a fluorine-containing alkyl succinic acid diester as a diester. 6. An aliphatic alkyl succinic anhydride or an aliphatic alkenyl succinic anhydride and an alcohol with a fluoroalkyl group, an alcohol with a fluoroalkenyl group, an alcohol with a fluorophenyl group, an aliphatic alkyl alcohol or an aliphatic alkenyl alcohol. Fluorine-containing alkyl obtained by addition reaction to give a monoester, and chlorinating the monoester to give a chlorinated carboxylic acid, and reacting the chlorinated carboxylic acid with a fluoroalkyl ether group-containing alcohol in the presence of a base catalyst to give a diester. Process for producing succinic acid diester.