JPS61183245A - Production of halogen-substituted benzophenone - Google Patents

Abstract

PURPOSE:To obtain the title compound useful as a polymerization inhibitor, ultraviolet light absorber, photopolymerization initiator, or flame retardant or an intermediate for agricultural chemicals, medicines, etc. in high yield, by oxidzing a halogen-substituted diphenylmethane as a raw material with molecular oxygen in the presence of an active cobalt oxide catalyst. CONSTITUTION:A halogen-substituted diphenylmethane expressed by formula I (X1-X5 and X'1-X'5 are H or halogen, provided that two or more may be same but at least one is halogen), e.g. 4, 4'-difluorodiphenylmethane, is oxidized with molecular oxygen in the presence of an active cobalt oxide catalyst (black powdery substance obtained by treating cobalt hydroxide with an oxidizing agent) to give a halogen-substituted benzophenone expressed by formula II, e.g. 4, 4'-difluorobenzophenone. USE:An intermediate for test agents, particularly 4, 4'-difluoro-and 4,4'-dichloro- benzpohenone is a monomer for aromatic polyether ketone based polymers having improved heat and chemical resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for producing halogen-substituted benzophenones. More specifically, the present invention relates to a method for producing halogen-substituted benzophenone by reacting halogen-substituted Schiffenylmethane with all molecular oxygen.

(Prior Art) It is known that the corresponding halogen-substituted benzophenones can be obtained by reacting halogen-substituted diphenylmethane with chemicals that are total oxidizing agents. For example, Mansaku recommends using selenium dioxide (D.S. Tarbell et al.
J, Amer, C'hem, Soc,, vol. 74.

244, 1952) and the method using manganese dioxide (E, F. Pratt et al., J. Org, Cbem.
, Vol. 28, p. 638, 1965), but these reactions are not catalytic reactions and require a stoichiometric amount or more of oxidizing agent, which poses problems for industrial implementation. be.

On the other hand, several methods have been reported for producing benzophenone by oxidizing unsubstituted diphenylmethane with molecular oxygen. For example, a method using activated cobalt oxide (
J. S. Belew et al. Chem, Commun
, .

1970, p. 635), and a method using an alkali catalyst in a special solvent (% 1970-144548).
, or a method of catalytic oxidation in the gas phase using an oxide of lead, vanadium, molybdenum, tungsten, titanium, etc. as a catalyst (JP-A-59-216846, JP-A-59-
2192AB Publication) and the like are known.

However, oxidation of halogen-substituted diphenylmethane with molecular oxygen corresponds to! A method for producing -logen-substituted penzophenones has hardly been proposed, and the influence of halogen as a substituent has not been known at all.

(Means and Effects of the Invention) Therefore, the present inventors conducted repeated studies to find a method for catalytically producing halogen-substituted penzophenone in high yield from halogen-substituted diphenylmethane, and as a result, the present invention was completed.

That is, the present invention provides a compound of the formula ([[
) is a method for producing halogen-substituted benzophenone.

(Tatashi, X, ,X, ,X, ,X4.Xll,X
γ,x; ,X,; ,X.

Moli represents hydrogen or halogen, respectively. Moreover, in these, two or more may be the same, but at least one is halogen. ) The activated cobalt oxide used in the present invention is a black powdery substance obtained by treatment with a cobalt hydroxide total oxidizing agent. Moreover, it is preferable to use cobalt hydroxide immediately after production. Such cobalt hydroxide is usually
It is prepared by adding alkaline earth metal hydroxide to an aqueous cobalt salt solution. The active cobalt oxide can also be prepared directly by simultaneously introducing an alkali hydroxide and an oxidizing agent into a solution of the cobalt salt in water.

Cobalt salts that can be prepared from such active cobalt oxide catalysts include inorganic salts such as cobalt sulfate, cobalt chloride, cobalt bromide, cobalt iodide, cobalt nitrate, cobalt carbonate, cobalt thiocyanate, and cobalt perchlorate. Salts with acids, salts with organic acids such as cobalt oxalate and cobalt acetate, and complex compounds such as tetraethylammonium tetrachlorocobaltate are used. Of course, even if these salts are hydrated salts, the oxidizing agent used in the preparation of the active cobalt oxide catalyst is preferably an ordinary inorganic oxidizing agent. Examples of such oxidizing agents include oxygen, aqueous peroxide beds or persulfuric acid, peroxides such as ozone, chlorine, hypochlorous acid and its salts, perchloric acid and its salts, and periodic acid. Halogen-containing oxidizing agents and the like are preferably used. Ozone and sodium hypochlorite are particularly preferably used.

The halogen-substituted diphenylmethane used as a raw material in the present invention is a compound represented by formula (I), and may be produced by any method.

(x, ,x, ,x, ,x, ,x, ,x; ,
x;
2-, 3-) fluorodiphenylmethane, 4-chlorodiphenylmethane and each 14-mer c2-. 5-) of chlorodiphenylmethane, 4-bromodiphenylmethane and each isomer (2-, S-) of bromodiphenylmethane, 4-iododiphenylmethane and each isomer of K(2-,
3-) such as iododiphenylmethane M, '1'7 fluorodiphenylmethane and each isomer (2,2'-, 2,3'-, 2,4'
−.

3,3'-,5,4''-) difluorodiphenylmethane, 4,4'-dichlorodiphenylmethane and each isomer (2,2'-,2,5'-,2,4'-,5,3
'-, 3, 4'-) dichlorodiphenylmethane, 4.
4'-dibromodiphenylmethane and each isomer (2,
2'-, 2, 3'-, 2.

4'-, 3,3'-, 5,4'-) dibromodiphenylmethane, 4.4'-syotodiphenylmethane and each isomer (2,2'-, 2,3'-, 2,4' -, 3
, 3'-, 3, 4'-) short diphenylmethanes with the same halogen fM k, 4-fluoro-4'-chlorodiphenylmethane and each isomeric K (2-fluoro-2'-chloro- 9
2-fluoro-3'-chloro-, 2-fluoro-4'-
Chloro-93-fluoro-27-chloro-53-fluoro-6'-chloro-,3-fluoro-4'-chloro-2
4-fluoro-2'-chloro-14-fluoro-3'-
(2) Dihalogenodiphenylmethane containing all different halogen species such as (fluorophenyl>
1 ' l ” l ” l 5# 4'l 216
+ ” + 3151 ” 12, 3, 2'-
, 2, 4, 2'-, 2, 5, 2'-, 2, 6, 2'-.

5, 5, 2'-, 2, 3, 5'-, 2, 4, 3'
-, 2, 5, 5'-.

2,6,3'-,3,5,3'-) trifluorodiphenylmethane, 4,4'-difluoro-3-chloro-diphenylmethane and each isomer of difluorochlorodiphenylmethane, 4,4'-difluoro-3 - Trihalogenodiphenylmethane M such as bromo-diphenylmethane and difluorodiphenylmethane of each isomer
, 3,4.3',4'-tetrafluorodiphenylmethane and each isomer of tetrafluorodiphenylmethane,
4.4'-difluoro-s, s'-cyclorodiphenylmethane and each isomer of difluorodichlorodiphenylmethane, 4.4'-difluoro-5,3'-dibromodiphenylmethane and each isomer of difluorodibromodiphenylmethane, and other tetrahalogens. Diphenylmethanes, 4,4'-difluoro-3,5,3',5'-tetrachloro-diphenylmethane and each isomer of difluorotetrachlorodiphenylmethane, 4,4'-difluoro-3,5,5',5 '-Tetrabromo-diphenylmethane and difluorotetrabromodi of each isomer7.
Hexahalogenodiphenylmethane of 1-nylmethane, bis(berfluorophenyl)methane.

Bis(barhalogenophenyl) such as bis(barchlorphenyl)methane, bis(barbromophenyl)methane
Methanes etc. are used. Among these, 1.3.3'
- and 4.4'-difluorodiphenylmethane, 3.
Particularly preferred are 3'- and 4,4'-dichlorodiphenylmethane.

Further, the molecular oxygen used in the present invention may be pure oxygen or a substance containing oxygen, and may be air, or other gases that do not inhibit the warping of air or pure oxygen, such as nitrogen, argon, helium, It may be diluted by adding an inert gas such as carbon dioxide. Further, depending on the case, gases such as hydrocarbons and halogenated hydrocarbons may be included.

The reaction of the present invention is represented by the following general formula.

(x, ',x, ,x, ,x, ',x, ,x,
', x; , Shin, xj, Kariu) Although this reaction can be carried out without a solvent, it is a preferable method to use a solvent that does not adversely affect the reaction. Such solvents include hexane, heptane,
Aliphatic hydrocarbons such as octane, nonane, decane, pentadecane, benzene, diphenyl, terphenyl, naphthalene (D aromatic hydrocarbons, chlorobenzene, bromobenzene, dichlorobenzene, dibromobenzene, chlornaphthalene, Halogenated aromatic hydrocarbons such as bromnaphthalene, aromatic nitriles such as IJ, heteroaromatic compounds such as pyridine, N,N-dimethylformamide, N,N-dimethylacetamide, tetramethylurea , amides such as N-methylpyrrolidone and hexamethylphosphoramide, sulfur-containing compounds such as dimethylsulfone, dimethylsulfoxide and sulfolane, organic acids such as acetic acid and propionic acid, esters such as ethyl acetate and ethyl benzoate, water,
and mixtures thereof are preferred.

In carrying out the reaction of the present invention, the amount of activated cobalt oxide catalyst used is not particularly limited, but is usually 0.001 mol per mol of halogen-substituted diphenylmethane.
~10,000 mol, preferably 0.01-1,000
It is in the molar range. Further, the amount of molecular oxygen used is not particularly limited, but is generally 0.1 to 10,000 mol, preferably 0.5 to s, o o o mol per 1 mol of N, rogane-substituted diphenylmethane. is within the range of

The temperature and time for carrying out the entire reaction of the present invention vary depending on the halogen-substituted diphenylmethane used, the type of solvent, the preparation method and amount of the catalyst, etc.
50'C,' 1 minute to 50 minutes for 50 hours, preferably 50 to 250C, 5 minutes to (Effects of the invention) The method of the present invention can convert halogen-substituted diphenylmethane to the corresponding halogen-substituted diphenylmethane in high yield. It became possible to produce benzophenone. Such halogen-substituted benzophenones are important as polymerization inhibitors, ultraviolet absorbers, photopolymerization initiators, flame retardants, etc., or as intermediates for agricultural chemicals, medicines, testing agents, etc. Furthermore, 4,4'-difluorobenzophenone and 0,a,4'-dichlorobenzophenone, which are some of these compounds, are aromatic polyetherketone polymers that have good heat resistance and chemical resistance. There is a demand for the development of an inexpensive manufacturing method for monomers.

(Example) The present invention will be further explained below with reference to Examples.

The present invention is not limited to these examples.

Example 1 (Preparation of activated cobalt oxide) Cobalt sulfate door H, 0140 p'i was dissolved in 2 t of water,
An aqueous solution of 30.89 m of sodium hydroxide dissolved in 400 ml of water was slowly added dropwise to the solution under stirring. Next, ozone-oxygen mixed gas-t (100N
It was blown at t/hr for 20 hours. The produced black precipitate kF was separated, washed with distilled water, and then dried under reduced pressure to obtain active cobalt oxide as a black powder.

(Oxidation reaction) 4.4'-difluorodiphenylmethane 2.17. Benzene 100'm7! The above-mentioned activated cobalt oxide 121 was added, stirred under reflux of benzene, and oxygen gas was introduced at a rate of 4501 Rt/mnI. After 2 hours, the reaction rate of 4.4'-difluorodiphenylmethane was 85%, and 4.4'-difluorobenzophenone was produced at a yield of 80%. As a result of continuing the reaction for an additional 4 hours, 4.4'-difluorodiphenylmethane (D anti-G ratio reached 96%) and 4.4'-difluorobenzophenone was produced at a yield of 91% and a selectivity of 95%.

Example 2 (Preparation of active cobalt oxide) Cobalt sulfate 1σD・7H,028,1y'Ir water 60
6% aqueous solution of sodium hypochlorite in which 8.47f of sodium hydroxide was dissolved was added dropwise over about 20 minutes with stirring. Next, after stirring was continued for 10 minutes, the generated black precipitate was separated from P, washed with distilled water, and dried under reduced pressure to obtain active cobalt oxide as a black powder.

(Oxidation reaction) The oxidation degree I'5' of 4.4'-difluorodiphenylmethane was carried out in the same manner as in Example 1 except that this activated cobalt oxide 122 was used. After 5 hours, the oxidation degree was %4.
．． 4'-difluorodiphenylmethano anti-G ratio u98%
The yield of 4,4'-difluorobenzophenone was 95%.
, was generated with a selectivity of 97chi.

Example 3 4.4'-Dichlorodiphenylmethane 31 and 10 ft of activated cobalt oxide prepared in a similar manner to Example 2
The oxidation reaction was carried out in the same manner as in Example 1 except that . After 3 hours, 4,4'-dichlorobenzophenone was produced at a yield of 90% and a selectivity of 95%.

Example 4 An oxidation reaction was carried out in the same manner as in Example 2 except that 37 pieces of 2-bromodiphenylmethane were used instead of 4.4'-difluorodiphenylmethane. As a result, 2,-bromobenzophenone was selected in a yield of 81-5. I got it at a rate of 90.

Example 5 2.4 instead of 4.4'-difluorodiphenylmethane
．． The oxidation reaction was carried out in the same manner as in Example 2, except that 4ft of 4'-trichlorodiphenylmethane was used.
, 4.4'-trichlorobenzophenone yield 85%,
A selectivity of 91% was obtained.

Example 6 The oxidation degree i k was determined in the same manner as in Example 2, except that 4-fluoro-4/,70 rhodiphenylmethane 67 was used instead of 4.4'-difluorodiphenylmethane. Fluoro-4'-chloro-benzophenone was obtained with a yield of 90% and a selectivity of 96%.

Example 7 The activated cobalt oxide catalyst used in Example 2 was separated by filtration in a total oxygen atmosphere, and the oxidation reaction of 4,4'-difluorodiphenylmethane was repeated 'lts times in the same manner as in Example 1. fl knee 7:)i%4
．． 4'-difluorobenzophenone was obtained with similar results to Hoho.

Claims (3)

[Claims] (1) In the presence of an activated cobalt oxide catalyst, the formula (I)
A method for producing a halogen-substituted benzophenone represented by formula (II), which comprises reacting halogen-substituted diphenylmethane represented by formula (II) with molecular oxygen. ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) (However, X_1, X_2, X_3, X_4, X_5,
X'_1, X'_2, X'_3, X'_4, and X'_5 each represent hydrogen or halogen. Moreover, in these, two or more may be the same, but at least one is halogen. ) (2) The method according to claim 1, wherein the halogen-substituted diphenylmethane is 4,4'-difluorodiphenylmethane or 4,4'-dichlorodiphenylmethane. (3) The method according to claim 2, wherein the halogen-substituted diphenylmethane is 4,4'-difluoromethane.