KR100265922B1 - Process for preparing alpha-carbonyl-phospine oxides - Google Patents

Abstract

The present invention provides a process for the preparation of alpha-carbonylphosphine oxides by oxidizing alpha-hydroxyalkyl phosphine oxides with organic hydroperoxides or organic peroxide acids in the presence of compounds of Groups IV to VIII metals of the periodic table. And novel alpha-hydroxy benzyl phosphine oxides.

Alpha-carbonylphosphine oxide is used as photoinitiator for polymerizable compositions.

Description

Method for preparing carbonylphosphine oxide

The present invention New Production Method and Novel Method of Carbonylphosphine Oxide -Hydroxyalkylphosphine oxide.

Carbonylphosphine oxide is used as photoinitiator in polymerizable compositions.

EP-A 007,508 discloses the reaction of carboxylic acid chlorides with alkoxyphosphines A method for preparing carbonylphosphine oxide is described. The reaction produces stoichiometric amounts of alkyl chlorides as undesirable byproducts. In addition, some acid chlorides may be difficult to obtain. For example, 0,0-disubstituted benzoic acid can be prepared only by complex methods, ie by haloform reaction of the corresponding acetophenones (see EP-A 046,194). However, such benzoic acids are particularly preferred starting materials of photoinitiators which are of great industrial importance.

The disubstituted phosphine oxide is reacted with aldehydes and ketones in the presence of a base The production of hydroxyalkylphosphine oxides is described in J. Am. Chem. Soc., 79, 424 (1957). Phenyl-substituted compounds on carbon atoms are prepared.

Some para-substituted from diphenyl chlorophosphine, aqueous inorganic acids and aromatic aldehydes Preparation of hydroxybenzyldiphenyl phosphine oxide is described in J. Chem. Org. Chem., 34, 748 (1969), wherein para-substituents include methyl, methoxy, chlorine and nitro groups.

Also, as described in Tetrahedron Lett., 24, 5009 (1983), tertiary-butylhydroperoxide is used as a selective oxidizing agent for aliphatic and cycloaliphatic secondary alcohols in the presence of vanadil acetylacetonate. Methods of making are known.

It is an object of the present invention to use compounds which are readily available as starting materials It is to find a novel method for producing carbonylphosphine oxide. Another object is to have a particularly important primary product, namely With 2,6-disubstituted phenyl radicals on carbon atoms To prepare hydroxyphosphine oxide, To provide a method that can be converted to carbonyl phosphine oxide.

Therefore, the present inventors -Hydroxyalkyl phosphine oxide is oxidized to organic hydroperoxide or organic peroxy acid in the presence of Group IV to Group VI metal compounds of the periodic table, A method of preparing carbonylphosphine oxide has been found.

In addition, the present inventors,

(a) reacting a disubstituted phosphine oxide with an aldehyde Producing hydroxyalkylphosphine oxide, and

(b) oxidizing the reaction product with an organic hydroperoxide or organic peroxy acid in the presence of a Group IV to Group VIII metal compound of the periodic table, A method of preparing carbonylphosphine oxide has been found.

We also find new Hydroxybenzyl phosphine oxide was found.

The first mentioned method Hydroxyalkyl phosphine oxide Conversion to carbonylphosphine oxide. This reaction can be represented by the following scheme:

As observed by the inventors, the properties of the substituents R and R 'have little effect on the results of the process.

Some of the starting materials are known in the art or can be prepared by known techniques. Houben-Weyl, Methoden der organischen Chemie, Vol. 12/1, pp. 154, 260, 475 (1963).

In view of the mainly required end products, compounds having the following substituents on the phosphorus atom are preferred:

C ₁ -C ₁₀ -alkyl, preferably C ₆ -C ₈ -alkyl, in particular n-octyl, such as methyl, ethyl, isopropyl, butyl and hexyl;

-C ₃ -C ₈ -cycloalkyl, preferably cyclopentyl and cyclohexyl;

-benzyl;

-C ₆ -C ₁₀ -aryl and preferably phenyl, wherein the phenyl radical is preferably chlorine, dichlorine, methyl, ethyl, isopropyl, tert-butyl, dimethyl, methoxy, ethoxy Or may be substituted by dimethoxy);

C ₁ -C ₆ -alkoxy, preferably ethoxy such as -methoxy, ethoxy, isopropoxy and butoxy;

Aryloxy, such as phenoxy or methylphenoxy;

Ethyloxyethoxy;

Benzyloxy;

S- or N-containing five or six membered rings, such as thienyl or pyridyl.

Substituents may be the same or different.

Particular preference is given to diphenyl phosphine oxide, phenylethoxy phosphine oxide and diethoxy phosphine oxide.

Preferred compounds are On the carbon atom have the following substituents:

Ethyl, isopropyl, n-propyl, n-butyl, tert-butyl, isoamyl, n-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, isononyl, dimethylheptyl, lauryl and stearyl C ₁ -C ₁₈ -alkyl such as;

C ₃ -C ₈ -cycloalkyl, preferably C ₅ -C ₇ -cycloalkyl, such as cyclopentyl, cyclohexyl and methylcyclohexyl;

C ₆ -C ₁₂ -aryl, such as naphthyl, preferably phenyl (the phenyl ring is for example halogen, such as chlorine or bromine, alkyl such as methyl, ethyl, isopropyl and tert-butyl, methoxy and Alkoxy, hydroxy, nitro, dimethylamino, such as isopropoxy, more preferably 2,6-disubstituted phenyl, such as 2,6-dimethylphenyl and 2,6-dichlorophenyl, and 2,4,6-tri May have one or more substituents, such as methylphenyl);

Heteroaryl such as furfuryl.

-Hydroxyalkyl phosphine oxide is reacted with organic peroxy acid or organic hydroperoxide.

Suitable organic peroxy acids are, for example, peracetic acid, perbenzoic acid and o-chloroperbenzoic acid. Organic hydroperoxides are preferred.

Preferred suitable compounds are tert-butylhydroperoxide and cumene hydroperoxide. All hydroperoxides used can be used commercially, ie in the form of hydrates or anhydrides which are diluted with an inert solvent such as tert-butanol, toluene or cumene. Generally, 1 to 3 moles, preferably 1 to 1.6 moles of hydroper oxide are used per mole of hydroxyalkyl phosphine oxide.

Suitable catalysts for the reaction are Group IV to Group VIII transition metal compounds. Basically IUPAC nomenclature is used herein. Transition metals include titanium, vanadium, chromium, manganese and iron. Among the metal compounds, compounds of vanadium, molybdenum and tungsten are preferable. More specifically, vanadium pentoxide, vanadil (IV) bis (diphenylphosphinate) and especially vanadil (IV) bis-acetylacetonate can be used. Generally, the amount of catalyst used 0.1 to 10 mole%, preferably 0.5 to 5 mole%, based on hydroxyalkyl phosphine oxide.

The reaction is advantageously carried out in an inert solvent. Suitable examples of inert solvents are tert-butanol, acetic acid, acetonitrile, methylene chloride, methyl tert-butyl ether, benzene, toluene and chlorobenzene. Generally, the amount of solvent is 50 to 90% by weight of the total batch.

All components may be mixed or, in a preferred embodiment, hydroperoxide may be added to the remaining components, optionally with cooling to 0-10 ° C. The temperature generally does not increase above 100 ° C., even at room temperature, because it is usually sufficient to complete the reaction in a few hours. Since pressure hardly affects the reaction, the reaction is generally carried out under standard pressure conditions.

Isolation of the product is carried out by known techniques, for example by distillation or crystallization.

Since hydroxyalkyl phosphine oxides are not commercially available, they must be prepared, starting from aldehyde The following two steps overall process is used to prepare carbonylphosphine oxide:

(a) reacting a disubstituted phosphine oxide with an aldehyde Producing hydroxyalkylphosphine oxide and

(b) oxidizing the reaction product with organic hydroperoxide or organic peroxy acid in the presence of Group IV-Group VI metal compounds of the periodic table.

Step (b) has already been described above fully.

Partial reaction (a) can be described by the scheme according to the following scheme:

The above description with regard to hydroxyalkyl phosphine oxides also suitably applies to substituents on phosphorus atoms and aldehydes.

Disubstituted phosphine oxides are known in the art or may be prepared by conventional techniques [see; Houben-Weyl, Methoden der organischen Chemie, Vol. 12/1 (1963), pp. 193-199, 321; Vol. E1 (1982), pp. 240-245, 274. In particular, it is economically important to prepare the compound in situ from the corresponding disubstituted phosphine chloride and at least stoichiometric amounts of water, preferably up to 2 moles of water per mole of phosphine chloride:

The acid liberated during the reaction can be neutralized by the addition of an aqueous base such as alkali metal carbonate, alkali metal bicarbonate or alkali metal hydroxide, with double sodium compounds being preferred. Neutralization can be carried out briefly, especially if the reaction is carried out in an inert organic solvent, since it is only necessary to mix the aqueous base and the organic phase and then continue the reaction.

Disubstituted phosphine oxides and aldehydes can be used in a 0.5: 1 to 1: 1 molar ratio, but they will generally react in stoichiometric amounts. Particularly useful is the conversion of chlorophosphine to phosphine oxide by carrying out the reaction in an organic solvent such as toluene, cyclohexane or petroleum ether. The process is generally carried out at room temperature because the reaction time is sufficient for several minutes to several hours. Of course, it can also be operated at elevated temperatures. To simplify the operation on an industrial scale, the process is generally carried out under standard pressure conditions.

It has been found that the reaction is advantageously carried out in the presence of a catalyst. Catalysts include alcoholates such as methylate, ethylate or isopropylate, with sodium alcoate being preferred. Alkali metal fluorides such as sodium fluoride and potassium fluoride are also suitable compounds. The catalyst may be used in an amount of 0.01 to 10 mol%, preferably 0.1 to 1 mol% based on the aldehyde. Isolation of the compound is carried out by known methods, preferably by crystallization.

Modifications of the reactions described above are carried out in which the hydrolysis of disubstituted phosphine chlorides is carried out in the presence of aldehydes and immediately after neutralization of the resulting reaction mixture, in the presence of group IV to Group VIII metal compounds of the periodic table. Reacting with peroxide or organic peroxy acid.

By the partial process step (a) described above, the new formula (I) Hydroxybenzyl phosphine oxide can be prepared:

Where

R ¹ and R ² are C ₁ -C ₁₈ -alkyl, preferably C ₆ -C ₈ -alkyl, such as hexyl and octyl; C ₅ -C ₈ -cycloalkyl, such as cyclohexyl; In particular C ₆ -C ₁₂ -aryl such as phenyl which may be mono- or polysubstituted by alkyl groups such as methyl, ethyl or isopropyl or alkoxy groups such as methoxy or ethoxy; Or C ₁ -C ₈ -alkoxy, preferably C ₁ -C ₄ -alkoxy, such as methoxy, ethoxy, isopropoxy or n-butoxy,

R ³ and R ⁴ are C ₁ -C ₆ -alkyl, preferably methyl and ethyl; C ₁ -C ₆ -alkoxy, preferably methoxy and ethoxy; Or halogen, preferably chlorine and bromine;

X is C ₁ -C ₆ -alkyl, preferably methyl; C ₁ -C ₆ -alkoxy, preferably methoxy; Halogen, preferably chlorine; Nitro; C ₁ -C ₄ -dialkylamino, or cyano;

n is 0 to 3, where n 1 may be the same or different), preferably 0 or 1.

Of the present invention Preferred examples of hydroxybenzyl phosphine oxide (I) are as follows:

-Hydroxy- (2,6-dimethylbenzyl) -diphenyl phosphine oxide

-Hydroxy- (2,6-dichlorobenzyl) -diphenyl phosphine oxide

-Hydroxy- (2,6-dimethoxybenzyl) -diphenyl phosphine oxide

-Hydroxy- (2,4,6-trimethylbenzyl) -diphenyl phosphine oxide

-Hydroxy- (3-chloro-2,4,6-trimethylbenzyl) -diphenyl phosphine oxide

-Hydroxy- (2,6-dimethylbenzyl) -bis (2,5-dimethoxyphenyl) -phosphine oxide

-Hydroxy- (2,6-dimethylbenzyl) -bis (4-methylphenyl) -phosphine oxide

-Hydroxy- (2,4,6-trimethylbenzyl) -bis (2,5-dimethylphenyl) -phosphine oxide

-Hydroxy- (2,4,6-trimethylbenzyl) -phenylepoxy phosphine oxide

The method of the present invention Preparation of hydroxyalkyl phosphine oxides, and their corresponding Provides simple oxidation to carbonylphosphine oxide. In addition, from readily available starting materials Particularly useful with 2,6-disubstituted phenyl groups on carbon Hydroxyalkyl phosphine oxides can be prepared.

Carbonylphosphine oxide is used as photoinitiator in polymerizable compositions such as recording compositions or coating materials (see EP-A 007,508).

EXAMPLE

One. Preparation of hydroxyalkyl phosphine oxide (process step (a))

Example 1

From chlorodiphenyl phosphine Preparation of -hydroxy- (2,4,6-trimethylbenzyl) -diphenyl phosphine oxide

To a mixture of 9 g (0.5 mole) water and 200 ml toluene, 110 g (0.5 mole) diphenyl chlorophosphine in 200 ml toluene is added. After 1 hour the reaction mixture was extracted with 90 ml of 20 wt% caustic soda solution and its organic phase was 74 g (0.5 mole) of 2,4,6-trimethylbenzaldehyde and 0.5 g 30% strength sodium methyl in methanol. Add late solution. The product begins to crystallize after 10 minutes and then isolated in the usual way. Yield: 95%, mp: 152-153 ° C.

Example 2

From diphenyl phosphine oxide Preparation of -hydroxy- (2,4,6-trimethylbenzyl) -diphenyl phosphine oxide

To a solution of 101 g (0.5 mole) diphenyl phosphine oxide in 150 ml toluene and 74 g (0.5 mole) 2,4,6-trimethylbenzaldehyde are added 0.5 g of a 30% by weight concentration of sodium methylate solution. After 10 minutes the product starts to crystallize and is isolated in the usual way. Yield: 98%

Example 3

Preparation of -hydroxy- (2,6-dichlorobenzyl) -diphenyl phosphine oxide

87.5 g (0.5 mole) of 2,6-dichlorobenzaldehyde is reacted in the same manner as described in Example 1.1. Yield: 96%, mp: 205-209 ° C

2. Preparation of Carbonylphosphine Oxide (Process Step (b))

Example 4

Preparation of 2,4,6-trimethylbenzoyl diphenyl phosphine oxide

Of 31.5 g (0.1 mol) in 150 g of chlorobenzene 15 g (0.12) of hydroxy- (2,4,6-trimethylbenzyl) -diphenyl phosphine oxide and 0.9 g (3.4 mmol) of vanadyl (IV) -bis-acetylacetonate over 30 minutes at 5 ° C Mole) and 70% by weight aqueous tert-butylhydroperoxide and stirred at room temperature for 20 hours. The product is isolated by crystallization. Yield: 82%, mp: 92-94 ° C.

When 17.2 g (0.10 mol) of m-chloroperbenzoic acid was used instead of tert-butylhydroperoxide, the yield was 49%.

Example 5

Preparation of 2,6-dichlorobenzoyl diphenyl phosphine oxide

15 g (0.04 mol) in 100 g chlorobenzene 12.9 g (0.1 mole) of 70% by weight aqueous 3 in -hydroxy- (2,6-dichlorobenzyl) -diphenyl phosphine oxide and 0.4 g (1.5 mmol) of vanadil (IV) bis-acetylacetonate Tea-butylhydroperoxide is added and the mixture is kept at 70 ° C. for 5 hours. Crystallization isolates the product. Yield: 64%, mp: 156-158 ° C.

Example 6

Preparation of (3-chloro-2,4,6-trimethylbenzoyl) diphenylphosphine oxide

15.4 g (0.04 mol) in 100 g chlorobenzene 8.2 g (0.06 mol) of -hydroxy- (3-chloro-2,4,6-trimethylbenzyl) -diphenyl phosphine oxide and 0.4 g (1.5 mmol) of vanadil (IV) bis-acetylacetonate 70 wt% concentration aqueous tert-butylhydroperoxide is added and crystallized after 20 hours to isolate. Yield: 81%, mp: 125-126 ° C.

Example 7

Preparation of 2,4,6-trimethylbenzoyl phenylethoxyphosphine oxide

26.5 g (0.08 mol) in 110 g chlorobenzene Hydroxy- (2,4,6-trimethylbenzyl) -phenylethoxy phosphine oxide and 1 g (38 mmol) of vanadil (IV) bis-acetylacetonate at a concentration of 28 g (0.22 mol) of 70% by weight aqueous 3 Tea-butylhydroperoxide is added and the mixture is stirred for 20 hours. The product is isolated by distillation. Yield: 55%, bp: 180 ° C. (0.1 mbar)

Example 8

Preparation of diethyl butyrylphosphonate (butyryl diethoxy phosphine oxide)

16.2 g (77 mmol) diethyl in 100 g chlorobenzene Add 30.4 g (0.24 mole) of 70 wt% concentration aqueous tert-butylhydroperoxide to hydroxybutyl phosphonate and 0.4 g (1.5 mmol) of vanadil (IV) bis-acetylacetonate and mix Stir for 4 days. The solvent is removed in vacuo. Yield (from residues): 25%

3. Preparation of Carbonyl Phosphine Oxides (Process Steps (a) and (b))

Example 9

Preparation of 2,4,6-trimethylbenzoyldiphenyl phosphine oxide

550 g (2.5 moles) of diphenylchlorophosphine are added to 2.2 kg of chlorobenzene, 50 g of water and 370 g (2.5 moles) of 2,4,6-trimethylbenzaldehyde. The mixture is stirred at room temperature for 1 hour, then 500 g of 20% strength caustic soda solution is added.

After addition of 20 g (75 mmol) of vanadil (IV) bis-acetylacetonate, 482 g (3.75 moles) of 70% strength aqueous tert-butylhydroperoxide are added to the reaction mixture at a temperature of 5-10 ° C. . After 6 hours the pH is adjusted to 9 by 20% strength caustic soda solution and the phases are separated. Crystallization isolates the product. Yield: 85%

Claims (11)

-Hydroxyalkyl phosphine oxide is oxidized with organic hydroperoxide or organoperoxy acid in the presence of Group IV to Group VIII metal compounds of the periodic table, A process for preparing carbonylphosphine osides. The process of claim 1 wherein phenyl substituted and / or ethoxy substituted on the phosphorus atom -Oxidizing hydroxyalkyl phosphine oxides. The method of claim 1, With 2,6-disubstituted phenyl radicals on carbon atoms -Oxidizing hydroxyalkyl phosphine oxides. The method of claim 2, With 2,6-disubstituted phenyl radicals on carbon atoms -Oxidizing hydroxyalkyl phosphine oxides. (a) reacting a disubstituted phosphine oxide with an aldehyde Producing hydroxyalkyl phosphine oxide, and (b) oxidizing the reaction product with an organic hydroperoxide or organic peroxy acid in the presence of a Group IV to Group VIII metal compound of the periodic table, A process for preparing carbonylphosphine oxide. 6. Process according to claim 5, characterized in that in step (a) aromatic aldehydes are used. A process according to claim 5, characterized in that in step (a) 2,6-disubstituted benzaldehyde is used. A process according to claim 5, characterized in that in step (a) phenyl substituted and / or alkoxy substituted phosphine oxides are used. Of the following general formula (I) Hydroxybenzyl phosphine oxide: Where R ¹ and R ² are each C ₁ -C ₁₈ -alkyl, C ₅ -C ₈ -cycloalkyl, C ₆ -C ₁₂ -aryl, or C ₁ -C ₈ -alkoxy, R ³ and R ⁴ are C ₁ -C ₆ -alkyl, C ₁ -C ₆ -alkoxy, or halogen, X is C ₁ -C ₆ -alkyl, C ₁ -C ₆ -alkoxy, halogen nitro, C ₁ -C ₁₄ -dialkylamino or cyano, n is 0 to 3, and when n is greater than 1, the substituents may be the same or different. 10. The process of claim 9 wherein R ¹ and R ² are each phenyl or C ₁ -C ₈ -alkoxy, R ³ and R ⁴ are each methyl, methoxy or halogen, X is methyl and n is 1 doing Hydroxybenzyl phosphine oxide. 10. The process of claim 9 wherein R ¹ and R ² are each phenyl or ethoxy, R ³ and R ⁴ are methyl, X is methyl and n is 1 Hydroxybenzyl phosphine oxide.