EP0005251B1 - Process for the preparation of sulfinates of 4,4'-diaminobenzhydrol and of its substituted products, and copying paper containing these compounds - Google Patents

Description

in welcher

• A und B unabhängig voneinander einen gegebenenfalls substituierten 1,4-Arylenrest und R_1' R₂, R₃ und R₄ unabhängig voneinander Wasserstoff oder einen gegebenenfalls substituierten Alkyl-, Cycloalkyl-, Aralkyl- oder Arylrest bedeuten, oder
• R₁ und R₂ bzw. R₃ und R₄ gemeinsam mit dem benachbarten Stickstoffatom einen heterocyclischen Ring bilden, oder
  einer oder mehrere der Reste
• R_1' R₂, R₃ und R₄mit dem Stickstoff und einem benachbarten Kohlenstoffatom des Restes A bzw. B einen heterocyclischen Ring bilden, und D für einen gegebenenfalls substituierten Alkyl-, Aryl-, Aralkyl-, Cycloalkyl- oder Hetarylrest steht. durch Umsetzung von 4,4'-Diaminobenzhydrolen der allgemeinen Formel
  
• in welcher die Reste R_1' R₂, R₃, R₄, A und B die gleiche Bedeutung wie in Formel I haben, mit Verbindungen der Formel
  
• in welcher der Rest D die gleiche Bedeutung wie in Formel hat, oder deren Alkali- bzw. Erdalkalisalzen unter wasserfreien Bedingungen in aliphatischen Mono- oder Dicarbonsäuren und gegebenenfalls anderen organischen Lösungsmitteln, dadurch gekennzeichnet, dass die Sulfinate durch Verdünnen mit wasserfreien organischen Lösungsmitteln ausgefällt werden.

The invention relates to a process for the preparation of sulfinates of the general formula

in which

• A and B independently of one another represent an optionally substituted 1,4-arylene radical and R _{1 '} R ₂ , R ₃ and R ₄ independently of one another are hydrogen or an optionally substituted alkyl, cycloalkyl, aralkyl or aryl radical, or
• R ₁ and R ₂ or R ₃ and R ₄ together with the adjacent nitrogen atom form a heterocyclic ring, or
  one or more of the residues
• R _{1 '} R ₂ , R ₃ and R ₄ form a heterocyclic ring with the nitrogen and an adjacent carbon atom of the radicals A and B, and D represents an optionally substituted alkyl, aryl, aralkyl, cycloalkyl or hetaryl radical. by reacting 4,4'-diaminobenzhydroles of the general formula
  
• in which the radicals R _{1 '} R ₂ , R ₃ , R ₄ , A and B have the same meaning as in formula I, with compounds of the formula
  
• in which the radical D has the same meaning as in formula, or the alkali metal or alkaline earth metal salts thereof under anhydrous conditions in aliphatic mono- or dicarboxylic acids and optionally other organic solvents, characterized in that the sulfinates are precipitated by dilution with anhydrous organic solvents.

The alkyl radicals mentioned in the formulas (I) and (11) are generally those having 1-6 C atoms. The alkyl radicals mentioned under D can have up to 20 carbon atoms. Particularly suitable substituents of the alkyl radicals are, for example, halogen, hydroxy, C ₁ -C ₄ alkoxy or cyano.

Aryl is preferably understood to mean phenyl or 1- or 2-naphthyl and aralkyl is benzyl and β-phenyl-C ₁ -C 4 -alkyl. The phenyl rings can be substituted, for example, by 1-4 radicals such as halogen, C ₁ -C ₄ alkyl, hydroxy, C ₁ -C ₄ alkoxy, C ₁ -C ₄ alkoxycarbonyl, carboxyl, amidocarbonyl, cyano, nitro, amidosulfonyl, C ₁ -C ₃ alkylcarbonylamino or benzoylamino.

Cycloalkyl is especially cyclopentyl and cyclohexyl, e.g. can be substituted by 1-4 radicals, in particular methyl.

Examples of heterocyclic rings which are formed by R ₁ and R ₂ or by R ₃ and R ₄ with the adjacent nitrogen atom are the piperidine, N-methylpiperazine and the morpholine ring. Examples of heterocyclic rings which are formed by R ₁ and / or R _{2 being} bound to the aromatic radical A or by R ₃ and / or R _{4 being} bound to the aromatic radical B are julolidine, lilolidine, N- Methyltetrahydroquinoline and 1,2-dimethylindoline called.

A and B preferably represent a 1,4-phenylene or 1,4-naphthylene radical. These radicals can be substituted by 1-4 substituents such as C ₁ -C ₄ alkyl, C ₁ -C ₄ alkoxy or halogen.

Halogen is understood to mean in particular fluorine, chlorine and bromine.

Suitable hetaryl residues D are e.g. the quinoline (5), quinoline (6) and indazole (7) residues.

in welcher

• R₅, R₆, R₇ und Ra unabhängig voneinander für Wasserstoff oder einen Alkylrest mit 1-4 Kohlenstoffatomen stehen, und
• Rg und R₁₀ unabhängig voneinander Wasserstoff, Methyl, Äthyl, Methoxy, Äthoxy, Chlor oder Brom bedeuten, mit Verbindungen der Formel
  
  in welcher
• R für gegebenenfalls durch Halogen substituiertes Alkyl mit 1-18 Kohlenstoffatomen oder für gegebenenfalls durch Halogen, Methyl, Äthyl, Hydroxy, Methoxy, Äthoxy, Nitro, Carboxyl oder Acetylamino substituiertes Phenyl steht, und Alkyl vorzugsweise durch 1 dieser Reste und Phenyl durch 1 oder 2 dieser Reste substituiert sein können,
• oder deren Alkalimetallsalzen in Gegenwart von aliphatischen Monocarbonsäuren und gegebenenfalls anderen organischen Lösungsmitteln unter Ausschluss von Wasser zu Verbindungen der Formel
  
• umsetzt, und die Verbindungen (VI) durch Verdünnen mit wasserfreien organischen Lösungsmitteln ausfällt.

A preferred procedure is that 4,4'-diaminobenzhydroles of the general formula

in which

• R ₅ , R ₆ , R ₇ and Ra independently of one another represent hydrogen or an alkyl radical having 1-4 carbon atoms, and
• Rg and R _{10 are} independently hydrogen, methyl, ethyl, methoxy, ethoxy, chlorine or bromine, with compounds of the formula
  
  in which
• R represents alkyl optionally substituted by halogen with 1-18 carbon atoms or phenyl optionally substituted by halogen, methyl, ethyl, hydroxy, methoxy, ethoxy, nitro, carboxyl or acetylamino, and alkyl preferably by 1 of these radicals and phenyl by 1 or 2 these radicals can be substituted,
• or their alkali metal salts in the presence of aliphatic monocarboxylic acids and optionally other organic solvents with the exclusion of water to give compounds of the formula
  
• converts, and the compounds (VI) precipitates by dilution with anhydrous organic solvents.

The process according to the invention is very particularly suitable for the production of sulfinates of Michler's hydrol (4,4'-tetramethyldiaminobenzhydrol).

Suitable solvents are monohydric and polyhydric alcohols, and also their ethers, for example methanol, ethanol, propanol, methyl glycol, ethyl glycol, butyl glycol, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, ethylene glycol, methyl glycol acetate, ethylene glycol nitrile diacetate, ethylene glycol nitrile diacetate, and ethylene glycol nitrile diacetate, ethylene glycol nitrile acetic acid, ethylene glycol nitrile acetic acid, ethylene glycol nitrile acetic acid, ethylene glycol nitrile acetic acid, ethylene glycol nitrile acetic acid, ethylene glycol nitrile acetic acid, acetylene glycol acetylene diacetate, acetylene glycol acetylene diacetate, acetic acid acetylene glycol acetic acid, acetylene glycol acetylene acetic acid, acetylene glycol acetylene acetylene, acetylene glycol acetic acid,

Suitable starting materials of the general formula are: 4,4'-diaminobenzhydro !, 4,4'-tetramethyldiaminobenzhydrol, 4,4'-tetraethyldiaminobenzhydrol, 4,4'-tetramethyldiamino-2,2'-dimethoxybenzhydrol, 4,4'-tetramethyldia- mino-2,2'-dimethylbenzhydrol, 4,4'-Bisbenzylmethylaminobenzhydrol, 4,4'-Bisbenzyläthylaminobenzhydrol, 4,4'-Bisdibenzylaminobenzhydrol, 4,4'-Bisphenylmethylaminobenzhydrol, 4,4 _'-bis- phenyläthylaminobenzhydrol, 4,4' -Bisäthyloxäthylaminobenzhydrol, 4,4'-Tetrachloräthyldiaminobenzhydrol, 4,4'-Bispiperidinobenzhydrol, 4,4'-Bismorpholinobenzhydrol, 4,4'-Bis-N-methylpiperazinobenzhydrol, Bis- (N-methyl-6-tetrahydroquinolyl) -methanol.

Examples of suitable low-molecular organic mono- or dicarboxylic acids are formic acid, acetic acid, propionic acid, glycolic acid, methoxyacetic acid, ethoxyacetic acid, oxalic acid, maleic acid and succinic acid. Acetic acid is preferred among these carboxylic acids.

Suitable sulfinic acids of the formula 111 are, for example, methanesulfinic acid, ethanesulfinic acid, propanesulfinic acid, butanesulfinic acid, decanesulfinic acid, dodecanesulfinic acid, octadecansulfinic acid, benzylsulfinic acid, 4-methylbenzylsulfinic acid, 4-chlorobenzylsulfinic acid, cyclohexylsulfinsulfonic acid, 2-chlorobenzene acid, benzene , 2-methylbenzenesulfinic acid, 4-ethylbenzenesulfinic acid, 4-methoxybenzenesulfinic acid, 4-ethoxybenzenesulfinic acid and 4-acetylaminobenzenesulfinic acid. Among these sulfinic acids, 4-methylbenzenesulfinic acid is particularly preferred. The reaction can be carried out at a temperature of 20-100 ° C, the preferred temperature range is 20-40 ° C.

A process for the preparation of sulfinates of 4,4'-diaminobenzhydrols by reacting these hydrolyses with sulfinic acids is already known (US Pat. No. 3,193,404). In this process, the sulfinate is precipitated by pouring the condensation solution into cold water or cold ammonium hydroxide solution, suction filtered and washed with water. According to this process, technically usable sulfinates are only obtained when starting from very pure diaminobenzhydrol. The common process for making Michler's hydrol (4,4'-tetramethyldiaminobenzhydrol) is to oxidize 4,4'-tetramethyldiaminodiphenylmethane with lead dioxide. This process produces dark-colored by-products, which dissolve in glacial acetic acid and, when diluted with water, precipitate together with the sulfinate and give it a dark, unsightly shade. Surprisingly, it has now been found that if the condensation solution is diluted exclusively with organic solvents, these impurities are kept in solution and a sulfinate is deposited which can be used without further purification to produce colorless copy papers. Working with water-containing organic solvents up to a water content of about 5% already leads to noticeably darker products, which, however, can still be used industrially. Solvents with a water content of more than 5% lead to a color number of 7 according to the iodine scale and are no longer suitable for the production of colorless copy papers.

example 1

170 g of Michler's hydrol (4,4'-tetramethyldiaminobenzhydrol), technical quality obtained by oxidation of 4,4'-tetramethyldiaminodiphenylmethane with lead dioxide, are dissolved in 700 g of glacial acetic acid at room temperature. 101.5 g of sodium p-toluenesulfinate are added to the dark blue solution. After 5 minutes, the crystallization of PTSMH (p-toluenesulfinate from Michlers Hydrol) begins. It is then diluted with 240 g of alcohol, the crystal suspension is left to stir for 4 hours at room temperature, filtered off with suction and the reaction product is washed with 400 g of alcohol in small portions until the crystals have a light color. Yield: 181.4 g; Melting point: 192-194 ° C; Color number of a 2.5% solution in dibutyl phthalate: 2-4.

If one of the following solvents is added to the condensation solution instead of ethanol and the procedure is otherwise the same, the p-toluenesulfinate from Michlers Hydrol is also obtained in very good quality and yield. Suitable solvents are: methanol, isopropanol, ethylene glycol, methyl glycol, ethyl glycol, butyl glycol, methyl glycol acetate, ethylene glycol diacetate, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, dioxane, tetrahydrofuran and acetonitrile.

Example 2

85 g of Michler's hydrol are dissolved in a mixture of 350 ml of propionic acid and 150 ml of alcohol, and 50.8 g of sodium p-toluenesulfinate are then added. The temperature is rising to 31 ° C and the p-toluenesulfinate from Michler's hydrol crystallizes. After 4 hours of stirring at room temperature, the reaction product is suctioned off and washed with 300 ml of alcohol in small portions until the filtrate runs off brightly. Yield: 90.4g; Melting point: 188-190 ° C. If the same amount of ethoxyacetic acid is used instead of the propionic acid and the procedure is otherwise the same, the p-toluenesulfinate from Michlers Hydrol is also obtained in good yield and quality.

Example 3

85 g of Michler's hydrol are dissolved in a mixture of 200 ml of glycolic acid and 150 ml of alcohol and 50.8 g of sodium p-toluenesulfinate are added. After stirring for 4 hours at room temperature, the reaction product is suctioned off and washed in small portions with a total of 300 ml of alcohol. Yield: 100.9 g; Melting point: 182-186 ° C.

Lactic acid can be used instead of glycolic acid with the same good result.

Example 4

85 g of Michler's hydrol are dissolved in a mixture of 50 ml of formic acid and 200 ml of ethanol and 50.8 g of sodium p-toluenesulfinate are added. After 10 minutes the sulfinate of Michler's hydrol crystallizes out. The suspension is allowed to stir for 4 hours at room temperature, is filtered off with suction and the reaction product is washed in small portions with 400 ml of alcohol until the filtrate is light, then with 0.5 l of a 1% aqueous sodium sulfinate solution.

Yield: 101.1 g; Melting point: 189-193 ° C

Example 5

40 g of Michler's hydrol are dissolved in 190 ml of glacial acetic acid. 15.5 g of sodium methanesulfinate are added to the solution. After 15 minutes, the methane sulfinate from Michler's Hydrol crystallizes out. The suspension is diluted with 100 ml of methanol, the mixture is stirred for a further 3 hours and the reaction product is filtered off with suction. 40.4 g of methanesulfinate are obtained. Melting point: 171-172 ° C. A sample recrystallized from methyl glycol acetate melts at 182-183 ° C.

Example 6

170 g of Michler's hydrol are dissolved in 700 ml of glacial acetic acid at room temperature and 104 g of sodium benzenesulfinate are added. After a few minutes, the Michlers Hydrol's benzenesulfinate crystallized out. The suspension is diluted with 200 ml of alcohol, stirred for a further 4 hours at room temperature and the reaction product is filtered off with suction. It is washed first with 500 ml of alcohol in small portions and then with 1 liter of water in which 20 g of sodium bicarbonate have been dissolved. After drying in vacuo, 192 g of benzenesulfinate from Michlers Hydrol, melting point 209-211 ° C.

If 146.4 g of sodium 4-chlorobenzenesulfinate are used instead of the sodium benzenesulfinate and the procedure is otherwise the same, 216.1 g of 4-chlorobenzenesulfinate from Michler's Hydrol, melting point 197-198 ° C.

Example 7

65.2 g of 4,4'-tetraethyldiaminobenzhydrol are dissolved in 150 ml of glacial acetic acid and 100 ml of alcohol. 32.4 g of sodium p-toluenesulfinate are added to this solution. As the temperature rose to 35 ° C., the p-toluenesulfinate of the tetraethyldiaminobenzhydrol slowly crystallized out. The mixture is left to stir for 22 hours at room temperature, the reaction product is filtered off and washed in small portions with 150 ml of alcohol until the filtrate runs off brightly and then with 500 ml of a 1% aqueous solution of p-toluenesulfinic sodium. After drying in vacuo, 61.1 g of p-toluenesulfinate of 4,4'-tetraethyldiaminobenz hydrol, melting point 146-148 ° C.

If you replace the 4,4'-tetraethyldiaminobenzhydrol in this example with one of the hydroles listed below and otherwise proceed in the same way, the sulfinates of these hydrols are also obtained in good yield and quality.

Suitable hydroles are: 4,4'-tetramethyldiamino-2,2'-dimethoxybenzhydrol, 4,4'-tetramethyl-diamino-2,2'-dimethylbenzhydrol, 4,4'-bisbenzylmethylaminobenzhydrol, 4,4'-bisbenzylethylaminobenzhydrol, 4,4'-Bisdibenzylaminobenzhydrol, 4,4'-Bisphenylmethylaminobenzhydrol, 4,4 _{'-Bisphenyläthylaminobenzhydrol, 4,4'} -bis- äthyloxäthylaminobenzhydrol, 4,4'-Bischloräthyl- äthylaminobenzhydrol, 4,4'-Bispiperidinobenzhydrol, 4,4 ' -Bismorpholinobenzhydrol, 4,4 _' -Bis-N-methylpiperazinobenzhydrol, bis- (N-methyl-6-tetrahydroquinolyl) -methane.

Claims (3)

1. Process for the preparation of sulphinates of the general formula

in which

A and B independently of one another denote an optionally substituted 1,4-arylene radical and R_1' R₂, R₃ and R₄ independently of one another denote hydrogen or an optionally substituted alkyl, cycloalkyl, aralkyl or aryl radical, or

R₁ and R₂, and R₃ and R₄, together with the adjacent nitrogen atom, form a heterocyclic ring or one or more of the radicals R₁, R₂, R₃ and R₄, with the nitrogen and an adjacent carbon atom of radical A or B, form a heterocyclic ring, and

D represents an optionally substituted alkyl, aryl, aralkyl, cycloalkyl or heteryl radical,

by reacting 4,4'-diaminobenzhydrols of the general formula

with compounds of the general formula

or alkali metal salts or alkaline earth metal salts thereof under anhydrous conditions in aliphatic monocarboxylic or dicarboxylic acids and optionally other organic solvents, characterised in that the sulphinates are precipitated by diluting them with anhydrous organic solvents.

2. Process according to Claim 1 for the preparation of sulphinates of the general formula

in which

R₅, R₆, R₇ and R₈ independently of one another represent hydrogen or an alkyl radical with 1-4 carbon atoms,

Rg and R₁₀ independently of one another denote hydrogen, methyl, ethyl, methoxy, ethoxy, chlorine or bromine and

R represents alkyl with 1-18 carbon atoms which is optionally substituted by halogen, or phenyl which is optionally substituted by halogen, methyl, ethyl, hydroxyl, methoxy, ethoxy, nitro, carboxyl or acetylamino,

by reacting 4,4'-diaminobenzhydrols of the general formula

with compounds of the formula

or alkali metal salts thereof, in the presence of aliphatic monocarboxylic acids and optionally other organic solvents with the exclusion of water, characterised in that the sulphinates are precipitated by diluting them with anhydrous organic solvents.

3. Colourless copying paper containing, as the colourforming agent, sulphinates which have been prepared by one of the processes of Claims 1 and 2.