KR900004586B1 - Preparation of trisphenol methanes - Google Patents

Abstract

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Description

Method for producing trisphenol methane

The present invention relates to a process for producing trisphenol methane.

Certain pharmaceutical hydroxy-containing triaryl methanes and methods for their preparation are described in US Pat. No. 31,467. Other general references to triaryl methane compounds include US Pat. Nos. 877,053: 3,449,418: 3,739,000: and 4,048,200. It is generally known that trisphenolic compounds can be prepared by condensation of alkoxy-substituted aromatic aldehydes or alkoxy-substituted aromatic ketones with excess substituted or unsubstituted phenols. See US Pat. No. 2,116,827: 3,787,451 and 4,394,496. US Patent No. 3,579,542 discloses a process for condensing P-hydroxyacetophenone with phenol using metal halides or acid catalysts to produce 4,4 ', 4' '-trihydroxytriphenylmethyl methane. It is also known to react salicylicaldehyde with certain phenolic compounds to give 4,4 ', 2' '-trihydroxyphenyl methanol. See Beilstein EII6, pp, 1111-2; EIV 6, pp.7630-1; And EIV 6, pp. 7643-4].

Ethyl orthoformate (triethoxymethane) is reacted with magnesium bromide Grignard reagent of 2,6-dimethylphenol to give 4,4 ', 4' '-methylidine tris (2,6-dimethylphenol). It is known to make [Chemical Abstracts 68: 12811g]. The process requires relatively expensive starting materials and requires special attention because the Grignard reagent reacts rapidly with water and oxygen.

To date, 4,4 ', 4' '-methylidine tris- (2,6-dimethylphenol) and related tris (p-hydroxyphenyl) methanol have been prepared from relatively expensive salicylates and derivatives thereof.

The present invention relates to a process for producing trisphenol methane of the general formula characterized by reacting 2,6-disubstituted phenol with salicylicaldehyde under reaction conditions to produce the product of the general formula:

Wherein each R is independently hydrogen, halogen or alkoxy, aryloxy or alkyl having up to 10 carbon atoms.

Surprisingly, tris (p-hydroxyphenyl) product is obtained without using p-hydroxyphenylketone or aldehyde as starting material. Tris- (4-hydroxy-3,5-disubstituted phenyl) methane is useful as a chemical intermediate and can be converted to tris epoxy resin using known methods.

The process of the present invention utilizes usefully 2,6-disubstituted phenols and salicyaldehyde.

2,6-disubstituted phenols having a boiling point which is preferably higher than that of phenol are usefully used in the process of the invention. 2,6-disubstituted phenols can have a wide variety of substituent changes as long as they do not inhibit the reaction. Examples of typical substituents include hydrogen, halogen, hydrocarbyl, substituted hydrocarbyl, alkoxy up to 10 carbon atoms, and aryloxy. Preferred substituents include alkyl having up to 10 carbon atoms. More preferred substituent is n-alkyl. Most preferred 2,6-disubstituted phenol is 2,6-dimethylphenol. Mixtures of the above phenols may be used and the 2- and 6-substituents may be different. Substituents are preferably such that phenol can be easily separated from the reaction mixture using known separation techniques (eg distillation).

2,6-disubstituted phenols can be used in specific amounts to yield the desired product. Typically, the molar ratio of 2,6-disubstituted phenol to salicyaldehyde is 3 to 10, preferably 4 to 6.

Contacting salicylicaldehyde and 2,6-disubstituted phenol can be carried out under a set of reaction conditions to yield the desired product. Preferably, the reactants are contacted in a distillation column reactor under certain combinations of conditions sufficient to distill the phenols above. Typical temperature ranges are 42 ° C to 120 ° C, preferably 60 ° C to 90 ° C. The pressure is typically between 2 mmHg and 100 mmHg, preferably between 6 mmHg and 30 mmHg.

The catalyst is optionally used in the process of the present invention and may be a specific material that catalyzes the reaction. Exemplary catalysts include acidic catalysts such as inorganic acids, organic acids (such as p-toluenesulfonic acid) and solid acids (such as acidic ion-exchange resins). Catalytic compounds can be used. When used, the catalyst is used in catalytic amounts. Preferably, the catalyst uses an amount such that the ratio of acid equivalents to the starting material salicyaldehyde is from 0.05 to 0.2.

When salicylicaldehyde and 2,6-disubstituted phenol are contacted as described above, tris (4-hydroxy-3,5-disubstituted phenyl) methane is produced. Preferred product compounds are represented by the general formula:

Wherein each R is independently halo, hydrocarbyl or substituted hydrocarbyl. R residues are defined as substituents on 2,6-disubstituted phenols.

The following examples are presented to illustrate the present invention.

Example 1

A mixture of 188.8 g of 2,6-dimethylphenol and 69.5 g of salicyaldehyde is stirred and heated at 118 ° C. for 24 hours in the presence of 3.0 g of toluene sulfonic acid monohydrate. Then, additionally 2,6-dimethylphenol 30.4 was added to the mixture, and the resulting mixture was distilled under a pressure of 180 to 200 mmHg in a 20-plate distillation column having a diameter of 1 inch (2.5 cm) to 35 g of the above phenol. Remove it. The material in the distiller is poured into 600 ml of room temperature methanol. The methanol solution is seeded with pure 4,4 ', 4' '-methylidine tris (2,6-dimethylphenol) and left to stand overnight. The resulting crystals were collected by filtration, washed with fresh methanol and dried in air to yield 25 g of orange crystals, which were identified as pure samples by nuclear magnetic resonance spectra.

Claims (10)

A process for preparing a compound of the general formula wherein the 2,6-disubstituted phenol is reacted with salicylic acid under reaction conditions to produce a product of the general formula

Wherein R is independently hydrogen, halogen or alkyl, alkoxy or aryloxy having 10 or less carbon atoms. The process of claim 1 wherein the reaction is carried out at a temperature of 42 ° C. to 120 ° C. 3. The process of claim 1 wherein the reaction is carried out in the presence of a catalyst. The process according to claim 1, wherein 3 to 10 moles of 2,6-disubstituted phenol are used per mole of salicyaldehyde. The method of claim 1 wherein each R is independently alkyl having up to 10 carbon atoms. The method of claim 5, wherein at least one R is methyl. 7. The process of claim 6 wherein each R is methyl and the reaction is carried out under distillation reaction conditions in the presence of an acidic catalyst. 8. The process of claim 7, wherein the catalyst is toluene sulfonic acid or a hydrate thereof. The method of claim 3, wherein the catalyst is an acidic catalyst. 10. The process of claim 9, wherein the catalyst is toluene sulfonic acid or a hydrate thereof.