Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
1999-10-27
2002-02-19
Rotman, Alan L. (Department: 1612)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
active
06348595
ABSTRACT:
SUMMARY
The invention relates to a process for preparing bis(hydroxymethyl) perylene-3,4,9,10-tetracarboximide wherein perylene-3,4,9,10-tetracarboximide is reacted with formaldehyde to yield the title compound, which is isolated or further reacted to form perylene derivatives which are useful as colorants for pigmenting high molecular weight organic materials.
BACKGROUND
Compounds from the class of the perylenetetracarboximides, or peryleneimides for short, have long been known in the art and are produced on an industrial scale. The compounds are recognized as being valuable colorants for high molecular weight organic materials.
U.S. Pat. No. 4,762,569 discloses N-substituted derivatives of perylene which are useful as dispersing agents for various pigments in non-aqueous media. The derivatives are prepared by reacting an amine, such as dimethylaminopropylamine, methylaminopropylaniine and the like, with tetracarboxylic acid dianhydnde of per-substituted condensed benzene ring of perylene. JO 1217056 discloses N-substituted derivatives of a perylene which are useful as dispersing agents for diketopyrrolopyrrole pigments in inks and paints obtained by a dispersion method. Perylene, for example, is reacted with dimethylbenzoguanamine, followed by reaction with tetrachlorophthalimide.
The present invention relates to a process for preparing a variety of N-substituted derivatives of perylene pigments wherein the N-substituted are linked to the perylene moiety by —CH
2
— or —O—CH
2
— linkages. The inventive process involves reacting perylene-3,4,9,10-tetracarboximide with formaldehyde to yield a bis(hydroxymethyl) perylene-3,4,9,10-tetracarboximide intermediate and further reacting the intermediate, with or without isolation, with a second reactant which reacts with the hydroxymethyl groups. The products of the reaction are useful as colorants for a variety of organic materials of high molecular weight. The bis(hydroxymethyl) perylene-3,4,9,10-tetracarboximide intermediate is useful as a colorant and as a synthon for the preparation of a variety of perylene derivatives and as a stabilizer for polymers.
DETAILED DESCRIPTION
The process according to the invention relates to a process of preparing a perylene derivative of the formula (I)
wherein X
1
and X
2
, each independently of the other, are organic radicals, D is chlorine or bromine, and n is an integer from 0 to 4; which perylene derivative contains from 0 to 6 moles of —SO
3
M per mole of the perylene derivative, wherein M is hydrogen or a metal or ammonium cation, which process comprises reacting perylene-3,4,9,10-tetracarboximide of the formula
in a first step with formaldehyde to yield a sulfonated or non-sulfonated form of bis(hydroxymethyl) perylene-3,4,9,10-tetracarboximide of the formula
which intermediate reacts in a second step with a precursor of the organic radicals, X
1
and X
2
, to yield the sulfonated or non-sulfonated form of the perylene derivative of formula (I). In general, the second reactant reacts with the bis(hydroxymethyl) perylene-3,4,9,10-tetracarboximide by a substitution reaction or by forming an —O— linkage.
The first step is preferably carried out by adding the perylene-3,4,9,10-tetracarboximide to a solution of paraformaldehyde in oleum (fuming sulfuric acid), concentrated sulfuric acid or polyphosphoric acid. The perylene-3,4,9,10-tetracarboximides of the above formula are known in the art and are commercially available.
When the reaction is carried out in concentrated sulfuric acid, some sulfonation occurs depending on the reaction temperature: the higher the temperature, the higher the degree of sulfonation. Reaction products containing very low to no sulfonation can be obtained under controlled conditions. The degree of sulfonation may be deliberately increased by using oleum, and the degree of sulfonation can be varied by using different reaction temperatures. Sulfur-free compounds can be easily prepared by employing polyphospheric acid as the reaction medium.
In general, a stoichiometic amount of formaldehyde is used in the first step. It is convenient to use paraformaldehyde although anhydrous formaldehyde also serves the purpose. Thus, the molar ratio of the perylene-3,4,9,10-tetracarboximide to the formaldehyde during the first step is preferably 1:2.
After the first step is complete, the resulting bis(hydroxymethyl) intermediate is reacted with the precursor or a different substrate to yield the perylene derivative of formula (I).
Preferably, both steps are carried out at a temperature of from 20 to 100° C. If a high degree of sulfonation is desired, the process is carried out at high temperatures, for example above 40° C., preferably using fuming sulfuric acid. If it is desirable to have a low degree of sulfonation, the reaction is maintained at a lower temperature, preferably 40° C. or below, preferably using concentrated sulfuric acid.
When using polyphosphoric acid as the reaction medium, it is advantageous to run the reaction at a temperature of between about 50 and 180° C., preferably between about 60 and 150° C., and most preferably between about 80 and 130° C. It is advantageous to employ a ratio of 1:4 of perylene diimide to polyphosphoric acid on a weight basis, with higher ratios, i.e., 1:20 or 1:10, also being possible if necessary.
After the reaction is complete, the perylene derivative is isolated by procedures conventionally used in the art for isolating perylenes, in particular by pouring the acid solution onto ice water while maintaining the temperature below 10° C., stirring the resulting aqueous slurry, followed by filtration, washing with water and drying to yield the perylene derivative in solid form.
Since it is not necessary to isolate the intermediate, the process according to the invention is preferably a one pot process. However, it is possible to isolate the intermediate prior to carrying out the second step, especially, for example, in those instances where it is desirable to carry out the second step in a solvent other than the solvent used in the first step.
Suitable solvents for the second step include concentrated sulfuric acid, fuming sulfuric acid, polyphosphoric acid and organic solvents which do not react with the bis(hydroxymethyl) perylene-3,4,9,10-tetracarboximide intermediate, especially polar organic solvents such as acetonitrile, benzonitrile, dimethylformide, dimethylsulfoxide, tetramethylenesulfone and the like.
It is also possible to carry out the second step in a solvent which reacts with the bis(hydroxymethyl) perylene-3,4,9,10-tetracarboximide intermediate to yield the desired product. For example, C
1
-C
10
alcohols are suitable solvents if the compound of formula (I) is the ether obtainable by reacting the bis(hydroxymethyl) perylene-3,4,9,10-tetracarboximide intermediate with the alcohol.
Preferably, the perylene derivatives of formula (I) contain from 0 to 4 moles of —SO
3
M per mole of the perylene derivative; most preferably from 0 to 2 moles per mole of perylene derivative. In general, if the reaction is carried out at about 40-50° C. in concentrated sulfuric acid, the product contains about 0 to 1.5 moles of —SO
3
M per mole of the perylene derivative. If the reaction is carried out at about 40-60° C. in fuming sulfuric acid, the product contains about 1 to 6 moles of —SO
3
M per mole of the perylene derivative, depending on the structural features of the second reactant.
M is preferably hydrogen, or an alkali metal, such as sodium or potassium, an alkaline earth metal, such as magnesium, an aluminum, a zinc or an ammonium cation. Examples of suitable ammonium cations include quaternary ammonium cations, such as trimethylcetylammonium or tributylbenzylammonium.
The organic radicals X
1
and X
2
are derivable from a precursor which reacts with the hydroxy groups of the bis(hydroxymethyl) perylene-3,4,9,10-tetracarboximide either by a substitution reaction or to form an —O— linkage.
Precursors which react with a hydroxyl group by a substitution reaction are generally compounds which comprise an aromatic radical, a heteroaromati
Ciba Specialty Chemicals Corporation
Crichton David R.
Rotman Alan L.
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