CA1082192A

CA1082192A - Process for the preparation of an n,n'-dimethyl- perylene-3,4,9-10-tetracarboxylic acid diimide pigment

Info

Publication number: CA1082192A
Application number: CA244,944A
Authority: CA
Inventors: Siegfried Schiessler; Ernst Spietschka; Reinhard Zunker
Original assignee: Hoechst AG
Current assignee: Hoechst AG
Priority date: 1975-02-04
Filing date: 1976-02-03
Publication date: 1980-07-22
Also published as: BR7600681A; US4153602A; IT1055858B; CH588530A5; DE2504481B2; JPS51103127A; FR2300115A1; GB1511751A; FR2300115B1; DE2504481A1; JPS5847425B2

Abstract

Abstract of the Disclosure:
N,N'-dimethyl-perylene-3,4,9,10-tetracarboxylic acid di-imide is obtained as a valuable pigment of a pure red shade, by reacting perylene-3,4,9,10-tetracarboxylic acid anhydride at low temperatures with a dilute aqueous solution of at least the four-fold molar amount of methylamine. The so-obtained bis-ammonium salt of the bis-N-methyl amide is then heated without isolation to effect ring closure while spiitting off two mols of water and two mols of methyl amine. The product can be used without any finish operation or cah be after-treated to yield a pigment of an exceptionally high trans-parency or of a good hiding power.

Description

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~a~ z The present invention ~eiates to a process for the pre-paration of N,N'-dimethyl-perylene-3,4,9,10-tetracarboxylic acid diimide (hereinafter also called "N,N'-dimethyl-peryl-imide") in -the form o~ a valuable red pigment ha~ing a high transparency, and to its use for pigmenting colorless sub-strates.
It is known that N,N'-dimethyl-perylimide can be prepared by reacting perylene-3,4,9,10-tetracarboxylic acid dianhydride with 2 mols of methyl amine in an aqueous medium. As results, howe~er, from German Offenlegungsschrift No. 1,963,728, this reaction yields crude products which do not yet possess pigment properties. For this reason, the crude dyestuff has to be converted into a pigment by grinding it with salts, as taught for example in German Offenlegungsschrift No. 1,914,208, No. 1,963,728 or No. 2,153,087. Moreover, German Auslege-schrift No. 1,272,270 teaches that the crude N,N'-dimethyl-perylimide can also be converted into a pigment by dissolving the dyestuff in sul~uric acid and introducing the solution into a large excess of water. Both finishing methods require a great economic expenditure, especially due to the necessary purification of waste water.
It has now been ~ound that N,N'-dimethylperylimide can be obtained in a single step as a brilliant pigment ha~ing a high tinctorial strength and transparency by reacting perylene-; 25 3~4,9,10-tetracarboxylic acid dianhydride with at least 4 mols of methyl amine per mol of dianhydride in a dilute aqueous medium at a low temperature to yield the bis-(methylammonium) salt o~ perylene-3,4,9,10-tetracarboxylic acid bis-(methyl amide), and then heating this salt to form the N9N'-dimethyl-perylimide.

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~t has further been found that pigments ha~ing an especially high tinctorial strength and transparency are ob-tained by carrying out this reaction in the presence of sur-face-active compounds, preferably of resin acids.
The reaction of perylene-3,4,9,10-tetracarbox~lic acid di-anhydride with at least 4 mols of methyl amine splits the anhydride rings to yield the bis-(methylammonium) salt of perylene-3,4,9,10-tetracarboxylic acid bis-(methylamide).
This compound is readily soluble in water and sufficiently stable at low temperatures. While 2 mols of methyl amine and

2 mols of water are split off therefrom, this compound is cyclized - at a slow rate at low temperatures and more speedily upon heating - to yield the N,N'-dimethylperylimide which is obtained in the form of a brilliant pigment of high tinctorial strength.
The reaction is advantageously carried out by introducing the perylene-3,4,9,10-tetracarboxylic acid dianhydride into an aqueous solution of methyl amine, since the methyl amine is then always available in excess. ~
The dianhydride may be used both in a solid form and in the form of an aqueous filter cake as obtained by the synthesis.
The amount of methyl amine advantageously ranges from 4 to 8 mols per mol of perylene-3,4,9,10-tetra-carboxylic acid di-anhydride, although an amount exceeding this quantity is possible b~t not economical. ~hen the amount of methyl amine used is reduoed to less than 4 mols per mol of perylene-3,4,9, 10-tetracarboxylic acid dianhydride, the pigment quality of the N,N'-dimethylper-ylimide obtained is impaired considerably. ~ -29 The amount of water, in which the reaction is carried out, ~- ' -,, ., . - - . - -.. ,: ., .' - ~

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may be varied greatly. Optimum pigment qual tJ is obtained when using 10 to 25 times the weight of water, calculated on the perylene~3,~,9,10-tetracarboxylic acid dianhydride.
The reaction of the perylene-3,4,9,10-tetracarboxylic acid dianhydride with methyl amine to yield the bis-(methylammonium) salt of the perylene-3,4,9,10-tetracarboxylic acid bis-(methyl-amide) is favorably carried out at temperatures of from O to 30C, preferably from O to 10C, a temperature of essentially less than 0C, though possible, is not suitable for economical reasons.
It is most advantageous to add the perylene-3,4,9,10-tetra-carboxylic acid dianhydride at O - 5C, whereupon a solution of the above bis-(methylammonium) salt is formed. This solution-is relatively stable at this temperature. Cyclization yielding the N,N'-dimethylperylimide is extremely slow at O - 5C. A reaction of perylene-3,4,9,10-tetracarboxylic acid dianhydride at higher temperatures prevents the formation of the above bis-(methyl-ammonium) salt since it causes simul-taneous cyclization yielding the N,N'-dimethylperylimide. Thers-~ore, with the reaction temperature increasing, the products obtained have a higher degree of opacity and a poorer tinc-torial strength.
- - To shorten the reaction time and ensure a quantitative reaction, the conversion of the bis-(methylammonium) salt into the N,N'-dimethylperylimide is completed at higher temperatures, for example by an aftertreatment at 70 - 150C, advantageously performed in a closed vessel to avoid losses in methyl amine.
~he pigments obtained have an especially high tinctorial 2g ~trength and brilliancy if the pigment ~ormation is carried out 4~

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in the presence of surface-~ctive compounds. As such sur-factants, ~hich allow pigment formation in the alkaline medium, anionic and nonionic compounds or mixtures thereof are pre-ferably used. The amount of surfactants used may be varied greatly, but amounts of from 0;5 to 5 %, calculated on the weight of perylene-3,4,9,10-tetracarboxylic acid dianhydride, are preferably added. As anionic compounds to be used ac-cording to the invention, there are mentioned, for example, salts of fatty acids having more than 10 carbon atoms, salts 10 of naphthenic acids, sulfated aliphatic alcohols having from 8 to 20 carbon atoms, sulfa~ed unsaturated higher fatty acids or the ~ters thereof, sulfated addition products of 1 to 30 mols of ethylene oxide on compounds containing preferably long-chained aliphatic radicals and reactive hydrogen atoms, such as fatty acidsS fatty acid amides, amines, aliphatic alcohols or alkylphenols, sulfates of N-acylated alkanolamines, alkyl-sulfonates, alkylaryl-sulfonates or sulfonates of polycarb-oxylic acid esters.
As nonionic compounds to be used according to the invention, there may be mentioned addition products of 1 to 30 mols of ethylene oxide on higher fatty acids, fatty acid amides, ali-phatic alcohols, aliphatic amines or alkylphenols, mono-glycerides of fatty acids or N-acylated alkanol-amines.
Especially valuable pigments having a high transparency are obtained if their formation is carried out in the presence of resin acids or salts thereof.
As resin acids, there are mentioned any natural or syn-thetic resi~ types containing one or more acid groups in the 2g ~olecule, for example colophony (rosin) or resins having a ', ' . -, .
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~8;~192 substantial percentage of colophony; hydrogenated or dimerized colophony r~sins~ hydrolyzable maleinate resins, hydrolyzable alkyd resins ~hich are free of oil, and phenol resins which are modified by colophony. The resin acids are preferably added in amounts of from 2 to 20 % by weight, especially from 5 to 10 % by weight, calculated on the perylene-3~4,9,10-tetra-carboxylic acid dianhydride.
The resin acids or the salts thereof are preferably added to the reaction mixture after the formation of the bis-(methyl-ammonium) salt of perylene-3,4,9,10-tetracarboxylic acid bis-(methylamide), but they may also be added with good success at an earlier or later moment during the reaction. It is also possible not to add the resin acids or the salts thereof until the condensation of the N,N'-dimethylperylimide is complete.
After the pigment has formed, the resin acids may be con-verted into insoluble resinates by adding appropriate metal ~- ~ 9/~,~ ~
; A salts, preferably calcium, barium or alifflinum salts or the aqueous solutions thereof, thus fixing them on the pigment.
This method provides pigments of a particularly high trans-parency. Transparent pigments are also obtained when the resin acids are not precipitated but predominantly washed off when isolating the pigment by f.iltration.
; The reaction may be carried out in the presence of a small amount of a condensation agent which promotes the formation of the imide, for example hydrochloric acid or suifuric acid.
According to an especially advantageous method for the pre-paration of the N,N'-dimethylperylimide, the perylene-394,9,10-tetracarboxylic acid dianhydride is introduced while stirring 29 into a dilute solution of methyl amine at a temperature of ., . . ~ . . - - , . , . - -~.

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HOE 7~,/F 030 ~ ~ Zi~ 2 fro~ O to 10C, stirring is -then continued for some time to complete ~he-formation of the bis-(methylammonium) salt o~
perylene-3,4,9,10-tetracarboxylic acid bis-(methylamide), then resin acid is added and finally the ~uantitative formation of N,N'-dimethylperylimide is brought about by heating the mixture to a temperature of from 70 to 150C. When the reaction is complete, the pigment is isolated by filtration in an almost quantitative yield. The pigment may then be freed from ad-herent traces of perylene-tetracarboxylic acid dianhydride or of incompletely condensed products by aftertreating it with dilute sodium hydroxide solution and subsequently washing it with hot water.
The advantage of the process of the invention is its~ood economy due to a single-step reaction that ~ields a valuable pigment without any finishing operation. Another substantial advantage of this process is that it does not pollute the water, since the almost quantitative reaction of perylene-

3,4,9,10-tetracarboxylic acid dianhydride with methyl amine provides a filtrate that contains only excess methyl amine.
Hence, after the consumed amount of methyl amine has been re- -placed, this filtrate can be used for further reaction~. It is, however, also possible to separate the exces.s methyl amine, ~or example by means of steam, and absorb it in the amount of water intended for further reactions.
The N,N'-dimethylperylimide obtained according to the invention is a brilliant red pigment having a high tinctorial strength and transperency as well as an outstanding fastness to light and weatheringO ~he pigment so obtained i~ much ~9 purer than the products obtained b~ methylation of perylene-, ' ' ' ' ' ' ' .
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HOE 75/~ ~30 1~8~192 3,4,9,10_tetracarboxylic acid diimide.
In some cases, the transparency of the N,N'-dimethyl-peryl-imide can be increased by aftertreating the aqueous suspension of the pigment in the presence of resin acids by means of an apparatus that causes mechanical fine division, for example bead mills, vibratory mills, roller mills or agitating mills, or high-speed agitators having a grinding effect.
An aftertreatment of the transparent pigments obtained by the condensation with organic solvents at an elevated temper-ature may also yield pigments having a good hiding power.
The pigment obtained according to the invention is suitable for pigmenting any kind of lacqu~r or varnish, for producing printing pastes, dis~empel or ernulsion paints, for the mass dyeing and coloration o~ synthetic, semi-.synthetic or natural macromolecular substances, such as for example polyvinyl chloride, polystyrene, polyamides or polyethylene. It may also be used for the spin-dyeing of natural, regenerated or man-made fibers as well as for the printing of textiles and paper.
It is especially suitable for pigmenting metal effect lac~uers.
The following Examples illustrate the invention, the par-ts and percentages being by weight unless stated otherwise.
E X A M P L E 1:
137 Parts vf perylene-3,4,9,10-tetracarboxylic acid di-anhydride were introduced while stirring at 0 - 5C within ~ hour into a mixture of 2,800 parts of -~7ater, 172 parts of a 50.2 % aqueous methyl amine solution and 2 parts of 96 %
sulfuric acid. Stirring was continued for 1 hour at 0 - 5C.
Ths temper~ture was ~hen evenly raised to the boil ~or 3 hours.
29 m e N,N'-dimethylperylimide ~ormed was then suction-filtered.

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~ 2 The filter-cake was i.ntroduced into 2,000 parts of a 3 %
potassium hydroxide solution and stirred for 1 hour at 90 _ 100C. The mixture was then suction-filtered and washed wi-th hot water until the filtrate remained colorless. The residue was dried at 60C in vacuo to yieid 143 parts of pigment.
The pigment thus prepared can be used to color stoved enamels brilliant intensive red shades according to known methods.
When the condensation reaction was carried out using 2 parts of sodium salt of octadecane-sulfonamidoacetic acid or 1 part of oxethylated nonylphenol, valuable pigments having a higher transparency were also obtained.
When the moist residue obtained by filtration was stirred ; into 2,000 parts of water, an aqueous solution o~ 11 parts of 1S the sodium salt of abietic acid was added and then, at 80 -90C,an aqueous solution of 21 parts of anhydrous calcium chloride was admixed, the pigment obtained after isolation and drying had a high tinctorial strength and an improved trans-parency.

78.4 Parts of perylene-3,4,9,10-tetracarboxylic acid di-anhydride were introduced while stirring at 0 - 5C within 1 hour into a mixture of 1,600 parts of water and 192 parts of a 27.6 % aqueous methyl amine solution. Stirring was con-tinued for 1 hour at 0 - 5C. Then a solution of 6 parts of - the sodium salt of abietic acid in 40 parts of water was added.
The temperature was then evenly raised to the boil within 1 hour, and the mixture was refluxed for 2 hours. The mixture 29 was then suction-filtered, the filter cake was washed first with _ 9 - - . . : : ' - . ' : ~
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~8Z1~2 a hot 3 % aqueous pot~-sium l;ydroxide solution and then with hot water. The residue was dried at 60C in vacuo.
The yield was 81.8 parts of N,N'-dimethylperylimide.
The pigment thus prepared can be used to color stoved enamels brilliant intense red shades having a high transparency.
Owing to its high transparency and tinctorial strengthS the pigment is excellently suitable for coloring metal effect lacquers.
When, instead of 6 parts of the sodium salt of abietic acid, 6 parts of the sodium salt of a resin mixture consisting of 85 % of abietic acid, 10 % of dihydro-abietic acid and 5 % of tetrahydro-abietic acid were used, a pigment having the same quality was obtained.
E X A M_P L E 3:
39.2 Parts of perylene-3,4,9,10-tetracarboxylic acid di-anhydride were introduced while stirring at O - 5C within 1 hour into a mixture of 850 parts of water and 53 parts of a 50.2 % aqueous methyl amine solution. Stirring was con-tinued for 1 hour at O - 5C. Then a solution of 3 parts of '7Dymerex"(R) (a resin consisting substantially of resin acid dimers, which i~ being commercialized by Messrs. Hercules Powder Company) in 30 parts of water and 5 parts of 2N sodium hydroxide solution was added. The temperature was then evenly raised to the boil within 1 hour, and the mixtu~e was refluxed for 2 hours. It was then suction-filtered while hot, and - the filter cake w~s washed with hot water. The residue was dried at 60C in vacuo to yield 41.3 parts of N,N'-dimethyl-perylimide 29 When used for coloring stoved enamels, the pi~nent obtained -- '10 ' '. , ' - .. ~
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is distinguished by a h gh +ransparency and is excellently suitable ~or coloring metal effect lacquers.
When the solids suspension that had been refluxed for 2 hours was ground for a short time in a disintegrating mill, for example a bead mill, and only then the N,N'-dimethylperyl-imide was isolated by filtration, the pigment obtained had an even higher transparency.
When, instead of 3 parts of "Dymerex", only 2 parts of this resin acid were used, a pigment of also a high transparency was obtained.
E X A M P L E 4:
117.6 Parts of perylene-3,4,9,10-tetracarboxylic acid di-anhydride were introduced while stirring at 25 - 30C within - 15 minutes into a mixture of 1,200 parts of water and 260 parts of a 27.6 % aqueous methyl amine solution. Stirring was con-tinued for 1 hour at 20 - 30C. The temperature in the auto-clave was then raised to 100C, and the mixture was stirred lor ; 2 hours at 100 - 110C. After cooling to 80C, the N,N'-di-methylperylimide was suction-filtered. The filter cake was washed first with a hot aqueous 3 % potassium hydroxide solution and then with hot water. The pigment was dried at 60C in vacuo to yield 123 parts of N,N'~dimethylperylimide.
The so-obtained pigment was used to color stoved enamels brilliant intense red shades according to known methods.
When the condensation reaction was carried out, instead of at 100 - 110C, at 130 to 140C in a closed vessel, the pigment obtained had also a high tinctorial strength.
Excess methyl amine could ~e eliminated from the filtrate 2~ by means of steam and then recovered for further reactions by - 11 _ ., ,, .~ ,. . ... . . . . . . . .. . ..
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E X A M P L E _ 5:
39.2 Pa,ts of perylene-3,~,9,10-tetracarboxylic acid di-anhydride were introduced while stirring at O - 5C within 1 hour into a mixture of 800 parts of water and 107 parts of a 24.7 % aqueous methylamine solution. Stirring was continued for 1 hour at O - 5C. Then a solution of 3.3 parts of the sodium salt of a technical-grade abietic acid (purity: 90 %) in 30 parts of water was added. The mixture was then heated to the boil within 1 hour and refluxed for 30 minutes. After cooling to 90C, a solution of 6 parts of anhydrous calcium chloride in 20 parts of water was added. Refluxing was then continued for another hour. The precipitate was suction-filtered while hot.
The filter cake was washed first with a hot 2 ~ potassium hydroxide solution and then with hot water, and the residue - was dried at 60C in vacuo to yield 44 parts of a pigment con-taining resinate.
The pigment thus prepared was used to color stoved enamels brilliant intense red shades according to known methods.
Owing to its high transparency, the pigment is excellently suitable for coloring metal effect lacquers.
When, instead of an aqueous solution of 3.3 parts of the sodium salt of technical-grade abietic acid, an aqueous ~5 ~olution of 3.3 parts of the sodium salt of tallic resin acid or of 3.3 parts of the sodium salt of colophony were usedt a pigment of comparable quality was obtained. Pigments having a very high transparency were also obtained by replacing the 29 sodium salt of abietic acid by the same amount of the sodi ..
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salt of a maleinate resin wh ch had been obtained by reacting abietic acid with maleic acid anhydride.

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39.2 Parts of perylene-3,4,9,10-tetracarboxylic acid di-anhydride were introduced while stirring at 0 - 5C uithin 1 hour, into a mixture of 820 parts of water and 80 parts of an aqueous 24.7 ~ methyl amine solution. Stirring was then continued for 1 hour at 0 - 5C. Then a solution of 3 parts of "Dymerex" in 40 parts of water and 5 parts of 2N sodium hydroxide solution together with 1 part of the sodium salt of octadecane-sulfonamidoacetic acid was added. The mixture was then heated to the boil within 1 hour and refluxed for 1 hour.
After cooling to about 90C, a solution of 6 parts of an-hydrous calcium chloride in 20 parts of water was added.
Refluxing was then continued for two hours. The precipitate was suction-filtered while hot and washed with hot water.
The residue was dried at 60C in vacuo.
The pigment thus prepared is very suitable for coloring metal effect lacquers owing to its particularly high trans-parency.
When instead of B0 parts of a 24.7 ~ aqueous methyl amine ; solution, only 52 parts of this solution were used, the pigment obtained had a slightly red~ced transparency.
When, instead of 1 part of the sodium salt of octadecane-sulfonamidoacetic acid, 1 part of an oxethylated colophony was used, a pigment of also a very high transparency was ob-tained.
When the moist filter cake obtained according to this ~9 method was introduced, prior to drying, into isopropanol at ., .: . ..... : . .................. ... .
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20 - 30C, stirred IOï sevoral hours at 20 - 30C, then iso-lated by filtration and dried at 60C in vacuo, the pigment obtained was d.istinguished, besides its high transparency9 by an improved dispersibility in lacquers, ~ ' ~
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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. In a process for preparing a pigmentary form of N,N'-dimethyl-perylene-3,4,9,10-tetracarboxylic acid diimide by reacting perylene-3,4,9,10-tetracarboxylic acid anhydride with an aqueous solution of methylamine the improvement comprising reacting said anhydride with a dilute solution of at least the four-fold molar amount of said amine at a temperature below 30°C, followed by heating to obtain the final product.

2. A process as claimed in claim 1, wherein in a first stage said anhydride and said amine are reacted at a temperature below 30°C to yield the bis-methylammonium salt of perylene-3,4,9,10-tetracarboxylic acid bis-(methyl amide) which then is transformed at a temperature of 70 to 150°C into said diimide.

3. A process as claimed in claim 2, wherein said bis-(methyl amide) is reacted further without isolation.

4. A process as claimed in claim 2, wherein said first stage is performed at 0 to 10°C.

5. A process as claimed in claim 1, wherein per each mol of said anhydride 4 to 8 mols of methylamine are added.

6. A process as claimed in claim 1, wherein the reaction is performed in the 10 to 25-fold amount of water, referred to the weight of said anhydride.

7. A process as claimed in claim 1, wherein to the reac-tion medium a surfactant is added.

8. A process as claimed in claim 7, wherein the surfact-ant is a resin acid or a water-soluble resin soap.

9. A process as claimed in claim 8, wherein the resin acid or resin soap is precipitated onto the reaction product by adding a metal salt capable of forming a resin soap which is sparingly soluble or insoluble in water.

10. A process as claimed in claim 8, wherein 2 to 20% of resin acid or resin soap, referred to the weight of said anhydride, are added to the reaction medium.

11. A process as claimed in claim 10, wherein the amount is 5 to 10%.