JP2003267984A - Pentaerythritol diphosphonate compound and method for producing the same - Google Patents

Abstract

(57) [Summary] To provide a resin with high flame retardancy.
New pentaerythritol diphosphonate compound
Is provided in an industrially advantageous manner with excellent productivity. SOLUTION: Pentaeri represented by the following general formula (1)
Thritol diphosphonate compound. Embedded image (Where R¹And R^FourMay be the same or different
And a hydrogen atom or a monovalent compound represented by the following general formula (2)
It is an aromatic group. R^Two, R^Three, R^FiveAnd R⁶Are the same or
May be different and 1 represented by the following general formula (2)
Is a valent aromatic group. ) Embedded image (Where Ar is a phenyl group, a naphthyl group, an anthryl
, Pyridyl and triazyl groups
Represents one group, and n is an integer of 0 to 5. R ⁷Is
Each may be the same or different, and on Ar
Other than the moiety attached to the phosphorus via the carbon atom of
Moieties, methyl, ethyl, propyl
Butyl, or its bonding group to Ar is an oxygen atom
Child, sulfur atom or aliphatic hydrocarbon group having 1 to 4 carbon atoms
Represents an aryl group having 5 to 14 carbon atoms. )

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a pentaerythritol diphosphonate compound having a specific structure and a method for producing the same. More specifically, it relates to a novel pentaerythritol diphosphonate compound which can be used as an additive such as a flame retardant, a crystal nucleating agent, a plasticizer and an antioxidant, and has an excellent effect as a flame retardant for resins, and a method for producing the same.

[0002]

2. Description of the Related Art Resins such as polycarbonate resin, polyphenylene oxide resin, polyester resin, ABS resin, styrene resin, epoxy resin and polyamide resin are widely used in mechanical parts, electric parts, automobile parts, etc. by utilizing their excellent physical properties. It is used in the field. On the other hand, since these resins are inherently flammable, in addition to the balance of general chemical and physical properties for use in the above applications,
In many cases, flame safety, that is, high flame retardancy is required.

As a method of imparting flame retardancy to a resin, a method of adding a halogen compound as a flame retardant and an antimony compound as a flame retardant aid to the resin is generally used.
However, this method has a problem that a large amount of corrosive gas is generated during molding or combustion. Moreover, in recent years, in particular, there is a concern about environmental impact at the time of product disposal. Therefore, flame retardants and flame retardant formulations that do not contain halogen at all have been strongly desired.

As a method of making a thermoplastic resin flame-retardant without using a halogen-based flame retardant, aluminum hydroxide,
It is widely known to add metal hydrates such as magnesium hydroxide. However, in order to obtain sufficient flame retardancy, it is necessary to add a large amount of the above metal hydrate, which has a drawback that the original characteristics of the resin are lost.

Aromatic phosphoric acid esters of triaryl phosphoric acid ester monomers and condensed phosphoric acid ester oligomers have also been frequently used as flame retardants for imparting flame retardancy to thermoplastic resins. However, the triaryl phosphate ester monomer typified by triphenyl phosphate significantly reduces the heat resistance of the resin composition, and since it has high volatility, a large amount of gas is generated during extrusion and molding, There was a problem in handling. Further, this compound has a problem that when the resin is heated to a high temperature, at least a part thereof is volatilized or is lost from the resin by bleeding or the like. Further, although the condensed phosphoric acid ester oligomer has improved volatility, since most of it is liquid, a liquid injection device is required for kneading with the resin, and there is a problem in handleability during extrusion kneading. It was

On the other hand, various studies have been made on disubstituted pentaerythritol diphosphonates centering on flame retardants for resins. By blending this compound with a thermoplastic resin, flame retardancy of the thermoplastic resin can be achieved. The thermoplastic resin composition in which the phosphonate compound is compounded does not deteriorate the properties such as heat resistance and impact resistance due to the compounding of the flame retardant, and the compound is volatilized during kneading, or bleeding occurs in the resin. It has features that cannot be lost from.

Several methods for producing the above-mentioned disubstituted pentaerythritol diphosphonate have been disclosed. For example, JP-A-5-163288 describes a production example in which diphenylpentaerythritol diphosphonate is obtained by reacting pentaerythritol with phenylphosphonic acid dichloride. In U.S. Pat. No. 4,174,343 there is a description of a preparation example in which the corresponding disubstituted pentaerythritol diphosphonate is obtained by reaction of diethyl pentaerythritol diphosphite with a halogenated derivative (eg benzyl chloride).

However, with respect to the pentaerythritol diphosphonate compound having a specific structure of the present invention, there has been a problem that such a target product cannot always be recovered in a high yield by a conventional production method.

[0009]

SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned problems of the prior art and to provide an industrially advantageous method with excellent productivity, in particular, a resin having a high flame retardancy. It is to provide a novel pentaerythritol diphosphonate compound that can be added.

The present inventor has conducted sincere investigations to achieve the above object, and as a result, the novel pentaerythritol diphosphonate compound can impart a high degree of flame retardancy to a resin and is industrially advantageous in production. The present inventors have found that such a compound can be produced by a method having excellent properties and have reached the present invention.

[0011]

That is, according to the present invention, a pentaerythritol diphosphonate compound represented by the following formula (1) is provided.

[0012]

[Chemical 8]

(In the formula, R ¹ and R ^{4, which} may be the same or different, are a hydrogen atom or a monovalent aromatic group represented by the following general formula (2). R ² , R ³ , R ⁵ and R ⁶
May be the same or different and may be represented by the following general formula (2)
It is a monovalent aromatic group represented by. )

[0014]

[Chemical 9]

(In the formula, Ar is a phenyl group, a naphthyl group,
Select from anthryl, pyridyl and triazyl groups
Represents any one of the groups described above, and n is an integer of 0 to 5
It R ⁷May be the same or different
, A portion bonded to phosphorus via a carbon atom on Ar
It may be attached to any moiety other than methyl, ethyl
Ru, propyl, butyl, or a linking group to Ar
Is an oxygen atom, a sulfur atom or an aliphatic group having 1 to 4 carbon atoms
Shows an aryl group having 5 to 14 carbon atoms through a hydrocarbon group.
You ) Pentaerythritol diphosphor represented by the above formula (1)
The nate compound is R in the formula (1).¹, R²And R³But,
Each R^Four, R^FiveAnd R⁶Must be the same substituent as
Is preferred. Among them, R¹And R^FourIs a hydrogen atom
It is preferable. Also, R², R³, R^FiveAnd R⁶But fe
It is preferably a nyl group.

As the above-mentioned pentaerythritol diphosphonate compound, specifically, 3,9-di ((diphenyl) methyl) -2,4,8,10-tetraoxa-3,
9-diphosphaspiro [5,5] undecane-3,9-
Dioxide, 3,9-di ((phenyl, 2-methylphenyl) methyl) -2,4,8,10-tetraoxa-
3,9-diphosphaspiro [5,5] undecane-3,
9-dioxide, 3,9-di ((phenyl, 2,4-dimethylphenyl) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide , 3,9-di ((phenyl,
2,6-Dimethylphenyl) methyl) -2,4,8,1
0-tetraoxa-3,9-diphosphaspiro [5,
5] Undecane-3,9-dioxide, 3,9-di ((phenyl, 2,4,6-trimethylphenyl) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5 ] Undecane-3,9-dioxide, 3,9-di ((phenyl, 3-methylphenyl) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3, 9-dioxide, 3,9-di ((phenyl, 3,5-dimethylphenyl) methyl) -2,4,8,10-tetraoxa-
3,9-diphosphaspiro [5,5] undecane-3,
9-dioxide, 3,9-di ((phenyl, 4-methylphenyl) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-
3,9-dioxide,

3,9-di ((di (2-methylphenyl)) methyl) -2,4,8,10-tetraoxa-
3,9-diphosphaspiro [5,5] undecane-3,
9-dioxide, 3,9-di ((di (2,4-dimethylphenyl)) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-
3,9-dioxide, 3,9-di ((di (2,6-dimethylphenyl)) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3, 9-dioxide, 3,9-di ((di (2,4,
6-trimethylphenyl)) methyl) -2,4,8,1
0-tetraoxa-3,9-diphosphaspiro [5,
5] Undecane-3,9-dioxide, 3,9-di ((di (3-methylphenyl)) methyl) -2,4
8,10-Tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide, 3,9-
Di ((di (3,5-dimethylphenyl)) methyl)-
2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide,
3,9-di ((di (4-methylphenyl)) methyl)-
2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide,

3,9-di ((phenyl, 2-iso-butylphenyl) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide, 3,9-di ((phenyl, 2,
4-di-iso-butylphenyl) methyl) -2,4
8,10-Tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide, 3,9-
Di ((phenyl, 2,6-di-iso-butylphenyl) methyl) -2,4,8,10-tetraoxa-3,
9-diphosphaspiro [5,5] undecane-3,9-
Dioxide, 3,9-di ((phenyl, 2,4,6-tri-iso-butylphenyl) methyl) -2,4,8,
10-Tetraoxa-3,9-diphosphaspiro [5,
5] Undecane-3,9-dioxide, 3,9-di ((phenyl, 3-iso-butylphenyl) methyl)
-2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide,
3,9-Di ((phenyl, 3,5-di-iso-butylphenyl) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-
3,9-dioxide, 3,9-di ((phenyl, 4-i
so-butylphenyl) methyl) -2,4,8,10-
Tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide,

3,9-Di ((di (2-iso-butylphenyl)) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-
3,9-dioxide, 3,9-di ((di (2,4-di-
iso-butylphenyl)) methyl) -2,4,8,1
0-tetraoxa-3,9-diphosphaspiro [5,
5] Undecane-3,9-dioxide, 3,9-di ((di (2,6-di-iso-butylphenyl)) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [ 5,5] undecane-3,9-dioxide, 3,9-di ((di (2,4,6-tri-iso-butylphenyl)) methyl) -2,4,8,10-tetraoxa-3, 9-diphosphaspiro [5,5] undecane-3,9-dioxide, 3,9-di ((di (3-is
o-butylphenyl)) methyl) -2,4,8,10-
Tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide, 3,9-di ((di (3,5-di-iso-butylphenyl)) methyl)-
2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide,
3,9-di ((di (4-iso-butylphenyl)) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide,

3,9-di ((phenyl, 2-tert-
Butylphenyl) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide, 3,9-di ((phenyl,
2,4-di-tert-butylphenyl) methyl)-
2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide,
3,9-Di ((phenyl, 2,6-di-tert-butylphenyl) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-
3,9-dioxide, 3,9-di ((phenyl, 2,
4,6-Tri-tert-butylphenyl) methyl)-
2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide,
3,9-di ((phenyl, 3-tert-butylphenyl) methyl) -2,4,8,10-tetraoxa-3,
9-diphosphaspiro [5,5] undecane-3,9-
Dioxide, 3,9-di ((phenyl, 3,5-di-t
ert-Butylphenyl) methyl) -2,4,8,10
-Tetraoxa-3,9-diphosphaspiro [5,5]
Undecane-3,9-dioxide, 3,9-di ((phenyl, 4-tert-butylphenyl) methyl) -2,
4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide,

3,9-Di ((di (2-tert-butylphenyl)) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-
3,9-dioxide, 3,9-di ((di (2,4-di-
tert-butylphenyl)) methyl) -2,4,8,
10-Tetraoxa-3,9-diphosphaspiro [5,
5] Undecane-3,9-dioxide, 3,9-di ((di (2,6-di-tert-butylphenyl)) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [ 5,5] undecane-3,9-dioxide, 3,9-di ((di (2,4,6-tri-tert
-Butylphenyl)) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide, 3,9-di ((di (3-
tert-butylphenyl)) methyl) -2,4,8,
10-Tetraoxa-3,9-diphosphaspiro [5,
5] Undecane-3,9-dioxide, 3,9-di ((di (3,5-di-tert-butylphenyl)) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [ 5,5] Undecane-3,9-dioxide, 3,9-di ((di (4-tert-butylphenyl)) methyl) -2,4,8,10-tetraoxa-
3,9-diphosphaspiro [5,5] undecane-3,
9-dioxide,

3,9-di ((phenyl, 1-biphenyl) methyl) -2,4,8,10-tetraoxa-3,
9-diphosphaspiro [5,5] undecane-3,9-
Dioxide, 3,9-di ((phenyl, 1- (2
2 ', 6,6'-Tetramethylbiphenyl)) methyl)
-2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide,
3,9-di ((phenyl, 4- (2-phenylpropyl) phenyl) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide, 3,9-di ((phenyl, 1-
Naphthyl) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-
3,9-dioxide, 3,9-di ((phenyl, 2-naphthyl) methyl) -2,4,8,10-tetraoxa-
3,9-diphosphaspiro [5,5] undecane-3,
9-dioxide, 3,9-di ((phenyl, 1-anthryl) methyl) -2,4,8,10-tetraoxa-
3,9-diphosphaspiro [5,5] undecane-3,
9-dioxide, 3,9-di ((phenyl, 2-anthryl) methyl) -2,4,8,10-tetraoxa-
3,9-diphosphaspiro [5,5] undecane-3,
9-dioxide, 3,9-di ((phenyl, 9-anthryl) methyl) -2,4,8,10-tetraoxa-
3,9-diphosphaspiro [5,5] undecane-3,
9-dioxide,

3,9-di ((phenyl, 1-pyridyl))
Methyl) -2,4,8,10-tetraoxa-3,9-
Diphosphaspiro [5,5] undecane-3,9-dioxide, 3,9-di ((phenyl, 2-pyridyl) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] Undecane-3,9-dioxide, 3,9-di ((phenyl, 3-pyridyl) methyl)
-2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide,
3,9-di ((phenyl, triazyl) methyl) -2,
4,8,10-Tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide, 3,9
-Di ((phenyl, 4-phenoxyphenyl) methyl)
-2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide,
3,9-di ((phenyl, 4-thiophenoxyphenyl) methyl) -2,4,8,10-tetraoxa-3,
9-diphosphaspiro [5,5] undecane-3,9-
Dioxide 3,9-di ((phenyl, 4- (2-phenylpropyl) phenoxyphenyl) methyl) -2,4
8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide,

3,9-di ((di (1-biphenyl)) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide, 3,9 9-di ((di (1- (2,2 ', 6,6'-
Tetramethylbiphenyl))) methyl) -2,4,8,
10-Tetraoxa-3,9-diphosphaspiro [5,
5] Undecane-3,9-dioxide, 3,9-di ((di (4- (2-phenylpropyl) phenyl)) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5 , 5] Undecane-3,9-dioxide, 3,9-di ((di (1-naphthyl)) methyl)-
2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide,
3,9-di ((di (2-naphthyl)) methyl) -2,
4,8,10-Tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide, 3,9
-Di ((di (1-anthryl)) methyl) -2,4
8,10-Tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide, 3,9-
Di ((di (2-anthryl)) methyl) -2,4,8,
10-Tetraoxa-3,9-diphosphaspiro [5,
5] Undecane-3,9-dioxide, 3,9-di ((di (9-anthryl)) methyl) -2,4,8,1
0-tetraoxa-3,9-diphosphaspiro [5,
5] undecane-3,9-dioxide,

3,9-di ((di (1-pyridyl)) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide, 3, 9-di ((di (2-pyridyl)) methyl)-
2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide,
3,9-di ((di (3-pyridyl)) methyl) -2,
4,8,10-Tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide, 3,9
-Di ((ditriazyl) methyl) -2,4,8,10-
Tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide, 3,9-di ((di (4
-Phenoxyphenyl)) methyl) -2,4,8,10
-Tetraoxa-3,9-diphosphaspiro [5,5]
Undecane-3,9-dioxide, 3,9-di ((di (4-thiophenoxyphenyl)) methyl) -2,4
8,10-Tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide, 3,9-
Di ((di (4- (2-phenylpropyl) phenoxyphenyl)) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-
3,9-dioxide,

3- (diphenyl) methyl, 9- (di (2
-Methylphenyl)) methyl-2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide, 3- (diphenyl) methyl, 9- (di (4-methyl) Phenyl)) methyl-2,
4,8,10-Tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide, 3-
(Diphenyl) methyl, 9- (di (2,6-dimethylphenyl)) methyl-2,4,8,10-tetraoxa-
3,9-diphosphaspiro [5,5] undecane-3,
9-dioxide, 3- (diphenyl) methyl, 9- (di (2,4,6-trimethylphenyl)) methyl-2,
4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide,

3- (diphenyl) methyl, 9- (di (1
-Naphthyl)) methyl-2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-
3,9-dioxide, 3- (diphenyl) methyl, 9-
(Di (2-naphthyl)) methyl-2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide, 3- (diphenyl) methyl, 9- (di ( 1-anthryl)) methyl-2,4
8,10-Tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide, 3- (diphenyl) methyl, 9- (di (2-anthryl)) methyl-2,4,8,10 -Tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide,

3- (diphenyl) methyl, 9- (di (1
-Pyridyl)) methyl-2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-
3,9-dioxide, 3- (diphenyl) methyl, 9-
(Di (2-pyridyl)) methyl-2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide, 3- (diphenyl) methyl, 9- (di ( 3-pyridyl)) methyl-2,4,8,
10-Tetraoxa-3,9-diphosphaspiro [5,
5] Undecane-3,9-dioxide, 3- (diphenyl) methyl, 9- (di (triazyl)) methyl-2,
4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide,

3,9-di ((triphenyl) methyl)-
2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide,
3,9-di ((tri (2-methylphenyl)) methyl)
-2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide,
3,9-di ((tri (4-methylphenyl)) methyl)
-2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide,
3,9-di ((tri (2,6-dimethylphenyl)) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide, 3, 9-di ((diphenyl, 2-methylphenyl) methyl) -2,4,8,10-tetraoxa-3,
9-diphosphaspiro [5,5] undecane-3,9-
Dioxide, 3,9-di ((diphenyl, 4-methylphenyl) methyl) -2,4,8,10-tetraoxa-
3,9-diphosphaspiro [5,5] undecane-3,
9-dioxide, 3,9-di ((diphenyl, 2,4-
Dimethylphenyl) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide and the like can be mentioned.

Among them, 3,9-di ((diphenyl) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide, 3,9- Di ((di (2-methylphenyl)) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide, 3,9-di ((di (2,4-dimethylphenyl))
Methyl) -2,4,8,10-tetraoxa-3,9-
Diphosphaspiro [5,5] undecane-3,9-dioxide, 3,9-di ((di (2,6-dimethylphenyl)) methyl) -2,4,8,10-tetraoxa-
3,9-diphosphaspiro [5,5] undecane-3,
9-dioxide, 3,9-di ((di (2,4,6-trimethylphenyl)) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3, 9-dioxide, 3,9-di ((di (3,5
-Dimethylphenyl)) methyl) -2,4,8,10-
Tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide, 3,9-di ((di (4
-Methylphenyl)) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide,

3,9-di ((di (2-iso-butylphenyl)) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-
3,9-dioxide, 3,9-di ((di (2,4-di-
iso-butylphenyl)) methyl) -2,4,8,1
0-tetraoxa-3,9-diphosphaspiro [5,
5] Undecane-3,9-dioxide, 3,9-di ((di (2,6-di-iso-butylphenyl)) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [ 5,5] undecane-3,9-dioxide, 3,9-di ((di (2,4,6-tri-iso-butylphenyl)) methyl) -2,4,8,10-tetraoxa-3, 9-diphosphaspiro [5,5] undecane-3,9-dioxide, 3,9-di ((di (3,5-
Di-iso-butylphenyl)) methyl) -2,4
8,10-Tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide, 3,9-
Di ((di (4-iso-butylphenyl)) methyl)-
2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide,

3,9-Di ((di (2-tert-butylphenyl)) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-
3,9-dioxide, 3,9-di ((di (2,4-di-
tert-butylphenyl)) methyl) -2,4,8,
10-Tetraoxa-3,9-diphosphaspiro [5,
5] Undecane-3,9-dioxide, 3,9-di ((di (2,6-di-tert-butylphenyl)) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [ 5,5] undecane-3,9-dioxide, 3,9-di ((di (2,4,6-tri-tert
-Butylphenyl)) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide, 3,9-di ((di (3,3
5-di-tert-butylphenyl)) methyl) -2,
4,8,10-Tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide, 3,9
-Di ((di (4-tert-butylphenyl)) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide is preferred.

Particularly preferred is 3,9-di ((diphenyl) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide.

The pentaerythritol diphosphonate compound represented by the above formula (1) of the present invention is obtained by diluting pentaerythritol and a phosphonic acid dihalide represented by the following general formula (3) with an organic solvent if necessary. Then, it can be obtained by reacting for 30 minutes to 30 hours in the presence of alkali, usually under the temperature condition of 0 ° C to 150 ° C.

[0035]

[Chemical 10]

(In the formula, R ⁸ is a hydrogen atom or a monovalent aromatic group represented by the following general formula (4). R ⁹ and R ¹⁰ may be the same or different, and A monovalent aromatic group represented by the general formula (4), wherein X represents Cl or Br.)

[0037]

[Chemical 11]

(In the formula, Ar is a phenyl group, a naphthyl group,
Select from anthryl, pyridyl and triazyl groups
Represents any one of the groups described above, and n is an integer of 0 to 5
It R ¹¹May be the same or different
, A portion bonded to phosphorus via a carbon atom on Ar
It may be attached to any moiety other than methyl, ethyl
Ru, propyl, butyl, or a linking group to Ar
Is an oxygen atom, a sulfur atom or an aliphatic group having 1 to 4 carbon atoms
Shows an aryl group having 5 to 14 carbon atoms through a hydrocarbon group.
You ) As the phosphonic acid dihalide represented by the above formula (3),
Specifically, (diphenyl) methylphosphonic acid diester
Chloride, (diphenyl) methylphosphonic acid dibroma
Id, (di (2-methylphenyl)) methylphosphonic acid
Dichloride, (di (4-methylphenyl)) methylpho
Sulfonic acid dichloride, (di (2,6-dimethylphenyl
)) Methylphosphonic acid dichloride, (di (2,4,
6-Trimethylphenyl)) methylphosphonic acid dichlora
Id and the like are mentioned and are preferably used.

The molar amount of the phosphonic acid dihalide used in this reaction is preferably in the range of 1.8 to 2.5 times the molar amount of pentaerythritol.

As the organic solvent, benzene, toluene,
Xylene, ethylbenzene, chlorobenzene, dichlorobenzene, 1,4-dioxane, tetrahydrofuran,
Examples thereof include those inert to the reaction such as dichloromethane, dichloroethane and chloroform, and among them, toluene, dichloromethane, dichloroethane and chloroform are preferable.

The alkali has an effect of smoothly proceeding this reaction and neutralizing the hydrogen halide generated in this reaction, for example, sodium hydroxide,
Sodium carbonate, sodium hydride, potassium hydroxide,
Examples thereof include inorganic substances such as potassium carbonate and organic substances such as pyridine and triethylamine, and among them, pyridine and triethylamine are preferable. These are used by counting the solubility in the above organic solvent. The molar amount of alkali is preferably 0.1 to 40 times, and more preferably 4 to 10 times, the molar amount of pentaerythritol.

The pentaerythritol diphosphonate compound of the present invention can be obtained from the reaction mixture after completion of the above reaction by a general separation means. For example, it can be obtained by removing most of the solvent, catalyst, salt and the like from the reaction mixture, followed by washing or recrystallization.

The phosphonic acid dihalide represented by the above formula (3) is obtained by adding the phosphonic acid diester represented by the following general formula (5) and a halogenating agent in the presence of a basic catalyst, if necessary with an organic solvent. It can be obtained by diluting and reacting for 30 minutes to 100 hours, usually under a temperature condition of 10 to 150 ° C.

[0044]

[Chemical 12]

(In the formula, R ⁸ , R ⁹ , and R ¹⁰ have the same meanings as defined in the above formula (3), and R ¹² represents an alkyl group having 1 to 4 carbon atoms.) Specific examples of the phosphonic acid diester represented by 5) include dimethyl (diphenyl) methylphosphonate, diethyl (diphenyl) methylphosphonate, di (n-propyl) (diphenyl) methylphosphonate and di (diphenyl) methylphosphonate di ( iso-propyl),
Diethyl (di (2-methylphenyl)) methylphosphonate, diethyl (di (4-methylphenyl)) methylphosphonate, diethyl (di (2,6-dimethylphenyl)) methylphosphonate, (di (2,4,6- Examples include diethyl (trimethylphenyl)) methylphosphonate, and among them, diethyl (diphenyl) methylphosphonate is preferably used.

As the halogenating agent, SOX ₂ , CO
X ₂ , PX ₃ , PX ₅ (X represents Cl or Br)
Are preferably used, specifically, SOCl ₂ , SOB
r ₂ , COCl ₂ , PCl ₃ , PBr ₃ , PCl ₅ , PBr ₅
Etc., among which SOCl ₂ is preferably used.

The molar amount of the halogenating agent used in this reaction is preferably 2.0 to 50 times the molar amount of the phosphonic acid diester represented by the above formula (5), and 2.1. The range of 10 times is more preferable.

In order to smoothly carry out such a reaction,
A basic catalyst is used. Specific examples of the basic catalyst include pyridine, triethylamine, pyridine hydrochloride, triethylamine hydrochloride, sodium methoxide, sodium ethoxide, N, N-dimethylformamide and the like, and particularly pyridine, triethylamine, pyridine hydrochloride, triethylamine. The hydrochloride salt is preferably used.

The molar amount of the basic catalyst used in this reaction is in the range of 0.001 to 0.3 times the molar amount of the phosphonic acid diester represented by the above formula (5). The range of 0.01 to 0.1 times is more preferable.

As the organic solvent, benzene, toluene,
Examples of xylene, ethylbenzene, chlorobenzene, dichlorobenzene, dichloromethane, dichloroethane, chloroform, N, N-dimethylformamide, pyridine and the like which are inert to the reaction are preferably used.

The alkyl halide generated by the reaction between the phosphonic acid diester represented by the above formula (5) and the halogenating agent is preferably removed from the reaction system during the reaction. As a specific method, a method of introducing an inert gas into the reaction solution and reacting while removing the generated alkyl halide outside the reaction system, or 0.013 to 80
A method in which the reaction is carried out under a reduced pressure condition of kPa and the reaction is carried out while removing the generated alkyl halide outside the reaction system is preferably adopted.

When these reaction conditions are satisfied, the desired phosphonic acid dihalide can be obtained in a high yield and a short reaction time.

The phosphonic acid diester represented by the above formula (5) comprises a trialkylphosphite represented by the following general formula (6) and a halogenated compound represented by the following general formula (7). It can be obtained by diluting with an organic solvent, if necessary, and usually reacting for 30 minutes to 100 hours under a temperature condition of 40 to 200 ° C.

[0054]

[Chemical 13]

(In the formula, R ¹² has the same meaning as defined in the formula (5).)

[0056]

[Chemical 14]

(In the formula, R ⁸ , R ⁹ and R ¹⁰ are the same as those in the above formula (5).
X means Cl or B
Indicates r. ) Specific examples of the trialkylphosphite represented by the above formula (6) include trimethylphosphite, triethylphosphite, tri (n-propyl) phosphite,
Examples thereof include tri (iso-propyl) phosphite and tri (n-butyl) phosphite. Among them, triethylphosphite is preferably used.

The halogenated compound represented by the above formula (7) is specifically diphenylmethane chloride, diphenylmethane bromide, di (2-methylphenyl) methane bromide, di (4-methylphenyl) methane bromide. , Di (2,6-dimethylphenyl) methane bromide, di (2,4,6-trimethylphenyl) methane bromide and the like, among which diphenylmethane bromide is preferably used.

The molar amount of the trialkylphosphite represented by the above formula (6) used in this reaction is based on the molar amount of the halogenated compound represented by the above formula (7).
The range of 1.0 to 10 times is preferable, and the range of 1.1 to 3 times is more preferable.

The alkyl halide generated by the reaction between the trialkyl phosphite and the halogenated compound is preferably removed to the outside of the reaction system during the reaction. By removing it to the outside of the reaction system, the trialkyl phosphite and the halogenated compound are removed. Side reactions with alkyl can be suppressed.
As a specific method, a method in which an inert gas is introduced into the reaction solution and the generated alkyl halide is removed from the reaction system to carry out the reaction, or 0.013 to 80 kPa
It is preferable to employ a method in which the reaction is carried out under reduced pressure conditions, and the reaction is carried out while removing the generated alkyl halide from the reaction system.

When these reaction conditions are satisfied, the desired phosphonic acid diester can be obtained in high yield and in a short reaction time.

The pentaerythritol diphosphonate compound of the present invention can be used, for example, as an additive such as a flame retardant, a crystal nucleating agent, a plasticizer and an antioxidant.

Further, the pentaerythritol diphosphonate compound of the present invention has an effect of imparting high flame retardancy to a resin, and can be preferably used as a flame retardant for a resin.

At this time, the blending amount of the pentaerythritol diphosphonate compound depends on the kind of the target polymer,
It depends on the required characteristics, required level, etc. and cannot be specified unconditionally, but it is preferably selected appropriately in the range of usually 1 to 50 parts by weight with respect to 100 parts by weight of the resin. When the amount is less than 1 part by weight, the flame retarding effect on the resin is insufficient, and when the amount is more than 50 parts by weight, the physical properties of the resin may be impaired or the cost may be disadvantageous. A more preferable blending amount is in the range of 3 to 30 parts by weight. The pentaerythritol diphosphonate compound may be used alone or in combination of two or more.

Examples of the resin flame retarded by the pentaerythritol diphosphonate compound of the present invention include polyolefin resins such as polyethylene and polypropylene, styrene resins such as polystyrene, high-density polystyrene, AS resin and ABS resin, and nylon. Polyamide resin such as 6, nylon 6/6, polyester resin such as polyethylene terephthalate, polybutylene terephthalate, polycarbonate resin, polyphenylene ether resin, polysulfone resin, polyphenylene sulfide resin, polyalkyl methacrylate resin, thermoplastic polyurethane elastomer, thermoplastic Examples thereof include polyester elastomers and epoxy resins.

When the pentaerythritol diphosphonate compound of the present invention is used as a flame retardant for thermoplastic resins in various applications, other halogen-based flame retardants may be added, if necessary.
A phosphorus-based flame retardant, a silicon-based flame retardant, a flame retardant aid such as antimony oxide or molybdenum oxide, and a filler such as aluminum hydroxide, silica, or polytetrafluoroethylene may be used in combination.

In addition, various additives, for example, antioxidants, ultraviolet absorbers, deterioration inhibitors such as light resistance stabilizers, lubricants,
Antistatic agent, release agent, plasticizer, sliding agent, reinforcing fiber such as glass fiber, carbon fiber, aramid fiber, aromatic polyester fiber, filler such as talc, mica, wollastonite, glass flake, pigment, etc. You may add the coloring agent of this.
The amount of the additive used is appropriately selected according to the kind of the additive within a range that does not impair mechanical strength such as heat resistance and impact resistance.

[0068]

EXAMPLES The present invention will be described below with reference to examples. These examples do not limit the scope of the invention to these examples.

[Example 1] (1) Production of diethyl (diphenyl) methylphosphonate Triethyl phosphite 1594 was placed in a 5-liter three-necked flask equipped with a stirrer, stirrer blade, generated gas collector, gas inlet tube, and thermometer. Into the reaction liquid was charged 100 g of 0.3 g (9.60 mol) and diphenylmethane bromide (1977.1 g, 8.00 mol).
And stirred for 30 hours. Ethyl bromide generated by the progress of the reaction was collected in a collector cooled to −78 ° C. through a fractionating pipe and a cooling pipe. After completion of the reaction, the reaction mixture was cooled to room temperature, and the generated ethyl bromide, excess triethyl phosphite, and by-produced diethyl ethylphosphonate were added at a temperature of 25 to 150 ° C., 0.013 to 4
It was distilled off under a reduced pressure condition of kPa to obtain 2312.8 g (7.60 mol) of diethyl (diphenyl) methylphosphonate.

(2) Production of (diphenyl) methylphosphonic acid dichloride A 5 liter three-necked flask equipped with a stirrer, stirring blades, reflux condenser, generated gas collector, gas inlet tube, and thermometer was added to the above (1). Diethyl (diphenyl) methylphosphonate obtained by the reaction 2312.8 g (7.60 mo)
l), thionyl chloride 2712.5 g (22.8 mol)
Then, 60.1 g (0.76 mol) of pyridine was charged, and while introducing nitrogen gas into the reaction solution, the mixture was heated to 90 ° C. and stirred for 30 hours. Ethyl chloride generated by the progress of the reaction was passed through a fractionating pipe and a cooling pipe to
It was collected in a collector cooled to 78 ° C. After completion of the reaction, the reaction mixture was cooled to room temperature, and the generated ethyl chloride and excess thionyl chloride were distilled off under a reduced pressure condition of 0.13 to 4 kPa at a temperature of 25 to 120 ° C. to obtain (diphenyl) methylphosphonic acid dichloride 2058. 5 g (7.22 mol) was obtained.

(3) A stirrer for producing 3,9-di ((diphenyl) methyl) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane-3,9-dioxide, In a 10-liter three-necked flask equipped with a stirring blade, a reflux condenser and a thermometer, the (diphenyl) methylphosphonic acid dichloride 205 obtained in the above reaction (2) was obtained.
8.5 g (7.22 mol), pentaerythritol 4
68.1 g (3.44 mol), pyridine 1169.4
g (14.8 mol) and 8200 g of chloroform were charged, and the mixture was heated to 60 ° C. under a nitrogen gas stream and stirred for 6 hours. After the reaction was completed, chloroform was added at 40 ° C for 1.3.
It was distilled off under reduced pressure of kPa, and the residue after distillation was dissolved in 3 L of methylene chloride. Distilled water (6 L) was added to this reaction-treated solution and stirred to deposit a white powder. This was collected by suction filtration, and the obtained white product was washed with methanol. Further, this white product was dried under reduced pressure at 100 ° C. and 0.13 kPa for 10 hours. The obtained solid is ³¹ P N
By MR, ¹ H NMR spectrum, 3,9-di (diphenylmethyl) -2,4,8,10-tetraoxa-
3,9-diphosphaspiro [5,5] undecane-3,
115-g of 9-dioxide (compound (A) in the formula (1), wherein R ¹ and R ⁴ are hydrogen atoms, R ² , R ³ , R ⁵ and R ⁶ are phenyl groups) It was confirmed.

¹ H NMR (chemical shift δ ppm, D
MSO-d6): 4.15 to 4.55 (m, 8H),
5.25 (d, 2H), 7.20 to 7.60 (m, 20
H) ³¹ P NMR (chemical shift δ ppm, DMSO-
d6): 20.9 Melting point by differential scanning calorimeter (DSC) analysis: 265 ° C. HPLC purity: 99% or more, acid value: 0.3 mg KOH / g or less Then, obtained by the above method with respect to 100 parts by weight of polypropylene resin. 30 parts by weight of the obtained compound (A) is added,
After uniformly mixing using a tumbler, pelletized by a 15 mmφ twin-screw extruder (KZW-15, manufactured by Techno Bell Co., Ltd.), injection molding machine (manufactured by Japan Steel Works, Ltd., J75).
A test piece having a thickness of 3.2 mm was molded using Si). The flame retardancy of the obtained test piece was evaluated according to the vertical combustion test specified in UL-94 of the UL standard of the United States, and was V-2 rank.

Reference Example 1 Production of diethyl (diphenyl) methylphosphonate 500 equipped with a stirrer, stirring blades, reflux condenser and thermometer
A milliliter three-necked flask was charged with 159.3 g (960 mmol) of triethylphosphite and 197.6 g (800 mmol) of diphenylmethane bromide, and heated to 100 ° C. and stirred under a nitrogen gas stream. Ethyl bromide generated as the reaction proceeded brought to a reflux state and the reaction temperature decreased. At this time, the generated ethyl bromide continued the reaction without being driven out of the reaction system. Thirty
After stirring for an hour, the progress was monitored using ¹ H NMR and ³¹ P NMR. As a result of analyzing the spectrum, the molar ratio of diethyl (diphenyl) methylphosphonate: diethyl ethylphosphonate was 64:36. Further, 36% of the charged amount of diphenylmethane bromide remained as an unreacted material.

[Reference Example 2] Production of (diphenyl) methylphosphonic acid dichloride In a 1-liter three-necked flask equipped with a stirrer, stirring blades, reflux condenser and thermometer, 229.7 g (755 mmol) of diethyl (diphenyl) methylphosphonate was added. 269.4 g (2265 mmol) of thionyl chloride was charged, and the mixture was heated to 90 ° C and stirred under a nitrogen gas stream. The reaction temperature decreased due to ethyl chloride generated as the reaction proceeded. At this time, the generated ethyl chloride continued the reaction without being driven out of the reaction system. After stirring for 30 hours, ¹
The progress was monitored using 1 H NMR and ³¹ P NMR. As a result of analyzing the spectrum, (diphenyl) methylphosphonic acid dichloride: (diphenyl)
The integration ratio of ³¹ P NMR spectrum of the intermediate to which ethyl methylphosphonate monochloride: thionyl chloride was added was 1:12:79.

Reference Example 3 Production of (diphenyl) methylphosphonic acid dichloride In a 1-liter three-necked flask equipped with a stirrer, stirring blades, reflux condenser and thermometer, 229.7 g (755 mmol) of diethyl (diphenyl) methylphosphonate, 270.5 g (2274 mmol) of thionyl chloride and pyridine 6.
Charge 0 g (7.5 mmol), and under a nitrogen gas stream,
The mixture was heated to 0 ° C and stirred. The reaction temperature decreased due to ethyl chloride generated as the reaction proceeded. At this time, the generated ethyl chloride continued the reaction without being driven out of the reaction system. After stirring for 30 hours, the progress was monitored using ¹ H NMR and ³¹ P NMR. As a result of analyzing the spectrum, the integration ratio of the ³¹ P NMR spectrum of the intermediate to which (diphenyl) methylphosphonic acid dichloride: (diphenyl) methylphosphonic acid ethyl monochloride: thionyl chloride was added was 42:23:
It was 28.

Reference Example 4 Production of (diphenyl) methylphosphonic acid dichloride In a 1-liter three-necked flask equipped with a stirrer, stirring blades, reflux condenser, generated gas collector, and thermometer, diethyl (diphenyl) methylphosphonate 229 0.7 g (755 m
mol), 269.3 g (2264 mmo) of thionyl chloride.
1) and 6.0 g (7.5 mmol) of pyridine,
The mixture was heated to 90 ° C. and stirred under a nitrogen gas stream. Ten hours after starting the reaction, the reaction mixture was cooled to 20 ° C., and the generated ethyl chloride was distilled out of the reaction system under reduced pressure. again,
The mixture was heated to 90 ° C. and stirred for 20 hours. ¹ H N
The progress was monitored using MR and ³¹ P NMR. As a result of analyzing the spectrum, (diphenyl)
Methylphosphonic acid dichloride: (diphenyl) methylphosphonic acid ethyl monochloride: The integral ratio of ³¹ P NMR spectrum of the intermediate to which thionyl chloride was added was 9
It was 0: 4: 4.

[0077]

The novel pentaerythritol diphosphonate compound of the present invention comprises a flame retardant, a plasticizer, an antioxidant,
It can be used as an additive such as a crystal nucleating agent, has a particularly high effect of imparting a high degree of flame retardancy to resins, and can be preferably used as a flame retardant for resins. The resin molded product containing the pentaerythritol diphosphonate compound has a high flame retardancy, a decrease in the heat resistance inherent to the resin is small, and is extremely useful for applications such as OA equipment and home electric appliances.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4H028 AA35 AA42 BA06                 4H050 AA01 AA02 AA03 AB80 BA69                       BD20 WA13 WA15 WA24 WA25                 4J002 AA001 BB031 BB121 BC031                       BC061 BG051 BN151 CD001                       CF001 CF061 CF071 CG001                       CH071 CK021 CL011 CL031                       CN011 CN031 EW126 FD136

Claims (9)

[Claims] 1. Pentaeri represented by the following general formula (1):
Thritol diphosphonate compounds. [Chemical 1] (In the formula, R¹And R^FourMay be the same or different
A hydrogen atom or a monovalent group represented by the following general formula (2)
It is an aromatic group. R², R³, R^FiveAnd R⁶Are the same or
May be different, and 1 represented by the following general formula (2)
It is a valent aromatic group. ) [Chemical 2] (In the formula, Ar is a phenyl group, a naphthyl group, or anthryl.
Selected from a group, a pyridyl group and a triazyl group
It represents one of these groups, and n is an integer of 0-5. R ⁷Is
Each may be the same or different and on Ar
Which is not attached to phosphorus via the carbon atom of
May be attached to a moiety, such as methyl, ethyl, propyl
Ru, butyl, or its linking group to Ar is an oxygen source.
Child, sulfur atom or aliphatic hydrocarbon group having 1 to 4 carbon atoms
Is an aryl group having 5 to 14 carbon atoms. ) 2. Pentaerythritol and the following general formula:
One or more kinds of phosphonic acid diha represented by (3)
Characterized by being produced by reaction with a rogenide
Pentaerythritol diphosphor represented by the above formula (1)
A method for producing a nate compound. [Chemical 3] (In the formula, R⁸Is a hydrogen atom or is represented by the following general formula (4).
Is a monovalent aromatic group. R⁹, And R^TenIs the same
It may be one or different and is represented by the following general formula (4).
It is a monovalent aromatic group. X represents Cl or Br
You ) [Chemical 4] (In the formula, Ar is a phenyl group, a naphthyl group, or anthryl.
Selected from a group, a pyridyl group and a triazyl group
It represents one of these groups, and n is an integer of 0-5. R ¹¹Is
Each may be the same or different and on Ar
Which is not attached to phosphorus via the carbon atom of
May be attached to a moiety, such as methyl, ethyl, propyl
Ru, butyl, or its linking group to Ar is an oxygen source.
Child, sulfur atom or aliphatic hydrocarbon group having 1 to 4 carbon atoms
Is an aryl group having 5 to 14 carbon atoms. ) 3. The phosphonic acid dihalide represented by the formula (3) according to claim 2, wherein the phosphonic acid diester represented by the following general formula (5) and a halogenating agent are present in the presence of a basic catalyst. The method for producing a pentaerythritol diphosphonate compound according to claim 2, which is produced by reacting. [Chemical 5] (In the formula, R ⁸ , R ⁹ , and R ¹⁰ have the same meanings as defined in the above formula (3), and R ¹² represents an alkyl group having 1 to 6 carbon atoms.) 4. The method according to claim 3, wherein the alkyl halide generated by the reaction between the phosphonic acid diester represented by the formula (5) and the halogenating agent is removed while being removed from the reaction system. 1. A method for producing a pentaerythritol diphosphonate compound according to claim 1. 5. The phosphonic acid diester represented by the formula (5) according to claim 3, is represented by a trialkylphosphite represented by the following general formula (6) and a following general formula (7). The method for producing a pentaerythritol diphosphonate compound according to claim 3, which is produced by a reaction with a halogenated compound. [Chemical 6] (In the formula, R ¹² has the same meaning as defined in the above formula (5).) (In the formula, R ⁸ , R ⁹ and R ¹⁰ have the same meanings as defined in the formula (5), and X represents Cl or Br.) 6. The alkyl halide generated by the reaction of the trialkyl phosphite represented by the formula (6) with the halogenated compound represented by the formula (7) is removed from the reaction system according to claim 5. The method for producing a pentaerythritol diphosphonate compound according to claim 5, wherein the reaction is carried out while removing the pentaerythritol diphosphonate compound. 7. The R in the formula (1) according to claim 1.
The pentaerythritol diphosphonate compound according to claim 1, wherein ¹ and R ⁴ are hydrogen atoms. 8. The R in the formula (1) according to claim 1.
The pentaerythritol diphosphonate compound according to claim 1, wherein ² , R ³ , R ⁵ and R ⁶ are phenyl groups. 9. A flame retardant for resins comprising the pentaerythritol diphosphonate compound according to claim 1.