CA1068265A

CA1068265A - Highly sulfonated triphenylmethane compounds, process for their preparation and their use as dyestuffs

Info

Publication number: CA1068265A
Application number: CA245,113A
Authority: CA
Inventors: Gunther Hencken; Manfred Hahnke
Original assignee: Hoechst AG
Current assignee: Hoechst AG
Priority date: 1975-02-06
Filing date: 1976-02-05
Publication date: 1979-12-18
Also published as: DE2504893A1; FR2300118B1; JPS51138722A; FR2300118A1; IT1054838B; GB1534752A; DE2504893C2

Abstract

Abstract of the disclosure:
New high-sulfonated triphenylmethane compounds had been found which are especially well suitable for the use as writ-ing ink dyestuffs. They possess a high solubility in water over a wide pH-range and are stable also in a prolonged storage.

Description

HOE 75/F ~6 10682t;S

The present invent~on relates to highly sulfonated tri-phenylmethane compounds, a process for preparing them and their use as dyestuffs.
Dyestuff inks which contain sulfonated triphenylpararos-anilines have been used for manv decades as blue writing inks.
The basic triphenylpararosaniline is obtained by a melting together of pararosaniline with aniline; the subsequent sul-fonation with concentrated sulfuric acid at elevated tempera-tures leads essentially to the formation of trisulfonic acid derivatives which are converted into the sodium salts (cf.
Ink Blue, C.I. 42,780). But only small yields are obtained in this reaction, and considerable amounts of undesired by-products are necessarily obtained.
. .
As triphenylmethane dyestuffs capable of being sulfonat-ed which may ser~e as substitutes, there may be used the tri-phenylmethane dyestuffs which can be prepared with little ex-penditure according to the process described in German Patent Specification No. 1.098.652 by the reaction of triphenylcar-binols or the salts thereof, which contain exchangeable sub-stituents in the p-position to the central C-atom, with aro-matic amines. However, it becomes evident that the sulfon-ation of such dyestuffs which are always substituted in the - phenyl rings far from the central C-atom in the m- or p-posi-t$on to the amino group, with concentrated sulfuric acid does not yield dyestuffs which are suitable for the preparation of blue dyestuff inks, as they do not meet the necessary require-~3 ments. Important criteria for dyestuff inks of this kind are~
among others, a high fluidity, a high tinctorial strength as 29 well as a good fastness to storage, i.e. the appearance of a

2 -! _ . . . ~

" ' ' : , ' ' " ' '` ~ ~ `

HOE 75/F O~
- ~068'~65 bottom or wall deposit , even after a long time of storage~is to be avoided.It has to be ensured in any case that there is an e~en flow of ink through the channel in the fountain pen. .
It has now been found that compounds of the general for-mula I

[ ~ ~ ;3 ]
HR5 ( S03A )n .,: , .
::, wherein R1 stands for a hydrogen or halogen atom, such as chlorine or bromine, or for a lower alkyl or lower alkoxy radical;
~ R2, R3 and R4 each~different or identical, represents hydrogen .i or a halogen atom, such as chlorine or bromine, a lower alkyl, lower alkoxy, phenyl, phenoxy, phenyl-amino, benzyl .i or phenethyl radical, or two of the radicals R2, R3 and R4, together with the benzene nucleus to which they are bound, j represe~t a naphthyl or an anthraquinone radical;
R5 ~snds for a hydrogen atom ~r the group $

i~ which R2, R3 and R4 are defined as above, the radicals .,, ~
R1 to R4 optionally being ~dentical or different in each case, howerer at least one of the radicals R2 or R3 being other:than hydrogen;
~ 3 -:'1,~ .

." . - ~ ' .
.' . . . : .
~ ., , , - . . . .
,.- .. ~ ~ , ` , . . . . .
'~, `:, ,. . : ''' ,' ' . ' .

- 1~68265 A represents hydrogen, sodium, potassium, calcium, magnesium, NH4 or N(R~4, wherein R stands for identical or different lower alkyl radicals optionally substituted by hydroxy, lower alkoxy radicals, two radicals R together with the nitrogen atom optionally forming a piperidine or morpholine radical, and n stands for an integer of from 3 to 6, are extremely suitable as dyestuffs, in particular for the preparation of blue inks.
Preference is given in particular to those dyestuffs of the formula I, 1~ in which Rl stands for hydrogen atoms, R2 and R3 are different and e~ch represents hydrogen, chlorine or bromine atoms, lower alkyl or lower alkoxy radicals, and wherein at least one radical R2 or R3 is other than hydrogen, R4 stands for hydrogen, A represents hydrogen, sodium, potassium or ammonium or an equivalent of calcium or magnesium, and n is an integer of from 3 to 6.
The meaning of n as an integer is calculated on 1 molecule of the ~' dyestuff. However, in most cases it may be any figure between 3 and 6, due ., v to the presence of a sulfonic acid mixture on a statistical average.

In the alkaline medium, the dyestuffs of the invention may also be ;
7, present in the form of the colorless or red carbinol or anhydro base, in which case all the sulfo groups introduced are at the same time present as metal or , ammonium salts.
iJ
The highly sulfonated triphenylmethane dyestuffs of the invention are obtained by way of the sulfonation of the corresponding triphenylmethane ~ dyestuff bases or salts by means '~

.
. ~
. " :
;.
,~
. ~

~:

~~ 75LF ~5 106826`S
of oleum or chlorosulfonic acid at an elevated temperature. In this way it is also possible to introduce se~eral sulfo groups into those dyestuffs, in which a m- and/or p-position of the aniline used for the dyestuff formation has been substituted.
Xt is of course also possible to sulfonate starting compounds having but a small number of sulfo groups (n ~ zero, but less than 3) in accordance with the invention. The sulfonation is effected partially at the inner benzene rings which are bound to the central C-atom. According to the invention, the sul-fonation is carried out using at least 4 times the amount ofoleum9 calculated on the non-sulfonated dyestuff, at a tem-perature in the range of from about 40 to 120C, preferably between about 60 to 100C. The concentration of the oleum is . .
in the range of from 5 to 40%~ preferably from 10 to 25% of S03. According to the invention, the sulfonation may also be carried out with a corresponding amount and concentration of chlorosulfonic acid in monohydrate. After the sulfonation, the product is worked up in known manner by dissolving it in ' water, by eliminating the sulfuric acid in the form of calcium ~i sulfate by means of calcium hydroxide, as well as by optional-;; ly precipitating the calcium which is bound to the sulfonated' dyestuff, with an appropriate precipitating agent, such as Na-, E-, NH4-carbonate, -oxalate, -sulfàte or -phosphate or ~i`l ~;, via a Gation exchanger resi~ (Na-, K-, N~4- or H-form), and ~!: 25 by subsequently evaporating the water to dryness of the product.
`l .
The triphenylmethane dyestuffs used as starting compounds can be obtained in known manner by mel~ing rosaniline or para-,` ro~aniline with an aniline which has been substituted accord-i ~g ~ ingly, ln the presence of acid catalysts (cf. Fierz-Davi~
~ 5 -,- ~ , - - , . . . - - . . -., ~ . : . ~ . . ., : , . . . . ..
- , ~ - , ~ . . . .. .. .

HOE i5/F 036 10~8265 E~nstliche organische Farbstoffe (1926j, pages 262 et seq., and BIOS Final Report, 1433, pages 30, 31 and 36). They can be prepared in a more advantageous manner, however, by react-ing triphenylcarbinols or the salts thereof, which contain ex~ha~g~bie subslit~enls in ihe p-position to the central C-atom, with aromatic amines carrying a substituent preferably in the m- or p-position to the amino group (see German Patent Specification No. 1,098,652).
The hlghly sulfonated triphenylmethane dyestuffs of the . 10 general formula (I) of the invention are extremely well soluble `
in water at a pH value in the range o~ from 1 to 10. They are thus clearly distinguished from the dyéstuffs of minor water-. solubility which can be obtained by way of the sulfonation .
:.1 with concentrated~ulfuric acid which has usually been applied ,~ .
so far: .
Dyestuff Sulfo groups per mole-: cule (n ~ 1) ,;,' 1) Triphenylpararosaniline, ~ 3 :.. ; sulfonated with 98% ~2S04 2) triphenylpararosaniline, ~ 4.5 sulfonated with 100~ H2S04

3) tris-(m-tolylamino)-trityl-sulfate ~ 3.5 .~ (or-alcohol), sulfonated with 1~0% H2S04

4) tris-(m-tolylamino)-trityl-sulfate ~ 5.5 `1 .
.l ~ (or-alcohol), sulfonated uith 20% oleum 1:
.j l~ - 6 --.
., ., . . . . ~. - . . , ~ . .. . -~0~ 75/F 0~6 1 ~ ~ 2~ 5 It is clearly evident that the dyèstuff No. 4 of the invention is sulfonated to a considerably higher degree and that therefore it shows the highest water-solubility. This is why it is suitable for the preparation of hi~her concen-tratR~ ~nk~ whi~h thuc show a ~gh~r tinçtorial s~reng~h; Be-sides it is possible to use this dyestuff for the preparation of highly concentrated stock solutions which may be diluted for further use.
By way of preparing aqueous or aqueous-organic solutions of the dyestuffs of the invention in a wide concentration range, preferably of from 0.5 to 3% by weight, optionally while also using an antibacterial additive as well as, option-ally, further additives, and by ad~usting the pH value with an acid in the range of from 0.5 to 5, preferably from 1 to 3, deep blue and brilliant wrlting inks are obtained. In cont~adistinction to the inks obtained from the lower sulfo-nated known blue ink dyestuffs, these inks are distinguished by an increased solution stability. Even after a prolonged ~, .
time of storage there is no formation of wall or bottom de-~, 20 posits, and the viscosity is not increased, either.
j Besides, in contradistinction to the known ink dyestuffs, -! the dyestuffs of the lnvention sho~ a reduced sensitivity to-wards hydrolysis and alkalie, due to the partial sulfonation of the inner phenyl rings next to the central C-atom so that i 25 an unob~ectionable stroke is obtained even on strongly alka-line papers with slightly acid inks. Only slightly acid aque-ous inks avoid corrosion at fountain pens made of steel.
1 The dyestuffs of the invention may be used as individual ! 29 dyestu~f3 as well as in mixturesO Besides, they may be used ... :... , .. . . . -. . ., ,. . . -, .
.. ,,., . : . ,, . .. :. . .:. . . .

in order to brighten and to tone inks containing other dye-stuffs, such as, for example, iron gallate inks.
The following Examples serve to`illustrate the invention.
The parts are parts by weight, the percentage figures are per cent b~ weight .
E X A M P ~ E 1:
36 Parts of a dyestuff having the formula ~ ~ 0~ ~ ~1 S04æ
~ ' ` ' . '~ . ' . ' ~ ' . NH
.~ . . l ~ - ~ ~ C~3 _ 2 .. .. . .. .. .

~, were introduced, with the exclusion of moisture, within 2 hours at a temperature of from 30 to ~5C, while stirring, into 110 parts of oleum of 20~ strength. The mixture was continued ;~
~, to be stirred for 30 minutes, was heated within 1 hour at a temperatureof from 85 to 90C, and the stirrlng was continued ~t for another 5 hours. The deep blue sl~lfonation mixture was !~ .
then introduced, while stirring, into 450 parts of water hav-~-~ ing room temperature. The blue solut~on obtained was heated at 80 to 90C, and a ~uspension of 95 parts of calcium hydroxide and 250 parts of water was slowly added, until a pH value of -i 4 was obtained. The mixture was heated to the boil, was con-~- tinued to be stlrred for 1 hour, the precipitated calcium sul-ate was filtered off, and the solution was then washed with ~ - 8 -'~:

~ ., . . , ... ,. , : ... , .~ . . .

OE 75/F 0~6 1~6826~

5~0 parts of water having a temperature of from 70 to 80C.
The combined filtrates were concentrated by distilling off water, to about ~00 parts, then 30 parts of ammonium carbonate were slowly added, the mixture was continued to be stirred fcr 1 hou~ Ln the vûiling state ~nd was fiilered w~ile hot.
The filtrate was evaporated to dryness i~ the drying closet at a temperature of from 80 to 100C. The dry product (72 parts) could be comminuted easily into granules. It was pre-sent in the form of the NH4 salt. If part of this dyestuff was dissol~ed in 100 parts of demineralized water, and the ; pH value was ad~usted to 2 by means of sulfuric acid, a bril-liant deep blue writing ink was obtained which had an excel-lent solution stability. Small amounts of a preservative, ~, ror example phenol or sorbic acid, or other additi~es could also be added to the ink.
Instead of the ammonium carbonate used, ammonium hydro-genocarbonate, -carbaminate, -oxalate,-phosphate or another precipitating agent could also be applied.
The an~sis showed an average content of 5.8 sulfo groups in the molecule.
`i E X A M P Il E 2:
35 Parts of a dyestuff of the formula .. _ . . . .
,,1, ~ ' ~ ~0_~ ~ ' SO~

3 ~ CH3 , ~ - g (,~ . .

-, . . . , ~ .. .. . .

HOE ?5/F ~6 1(~68265 were introduced, with the exclusion of moisture, within 2 hours at a temperature of from 35 to 40C while stirring, in-to 110 parts of oleum of 25% strength. The mixture was conti-nued to be stirred for ~0 minutes, was then slowly heated to 5 95 to 1~~ ad ;:as ^^r.tinue~ to b~ st~rred f^r 5 h^urs. The sulfonation mixture was introduced, while stirring, into 500 parts of water having a temperature of about 20C. A suspen-sion of 100 parts of calcium hydroxide and 250 parts of water was slowly added to the blue solution obtained, at a tempera-ture in the range of from 80 to 90C, until a pH value of 4 ;~ was obtained. The mixture was brought to the boil, was con-;~ tinued to be stirred for 1 hour, was filtered off from the pre-cipitated calcium sulfate and was washed with 500 parts of water having a temperature of from 70 to 80C. The combined filtrates were concentrated by distillation to about 250 parts, then 32 parts Or sodium carbonate were slowly added, the mix-ture was continued to be stirred for 1 hour in the boiling state and was filtered while hot. The filtrate was e~aporated to dryness in the drying closet at a temperature of from 80 to i 20 100C. The dry product (70 parts) was ground. It represented the sodium salt. If the pH value was ad~usted to 4 with sul-.j . .
furic acid, before evaporating to dryness, an e~ually good dyestuff was obtained.
The analysis showed an a~erage content of 5.7 sulfo groups in the molecule. An aqueous solution of 1% strength ha~ing a pH value of 2 had a deep blue color shade and was completely ~ ~ fast to storage.-`~ In~tead of sodium carbonate, use could also be made of so-., .
29 dium oxalate,-phosphate, -hydrogenocarbonate, or other precipl-~ ~ - 10 -. . . . .
', ~

- - ~ . - .
. . .. . : . -. . .

106~265 tating agents.
E X A M P ~ E 3 If instead of the sodium carbonate mentioned in Example 2, the same amount of anhydrous sodium sulfate was used, the mi~ed Ca, ~Ja-salt û the blue dyestuf was ~bta .. ed, *~.ich yielded also a blue ink having a high tinctorial strength as well as an excellent fastness to storage.
If instead of the dyestuff ~ulfate mentioned in Example 2, the free base of the same dyestuff (in carbinol or anhydro form) was used, an ink dyestuff was obtained which had the same good qualities.
E X A M P ~ E 4:
.
7 Parts of a 1:1 mixture of the dyestuffs of the formulae . ~
0' `13 so",~
' ~J
. NHR _ 2 .,, (R = H, ~

were introduced, while stirring, into 22 parts of oleum of 20~ strength during 2 hours, at a temperature of ~rom 20 to 30C. The mixture was heated within 1 hour to a temperature of from 80 to 85C, was continued to be stirred for 5 hours at this temperature and was finally introduced, while stir-ring, in~o 100 parts of water having room temperature. A mix-ture of 20 parts of calcium hydrsxide and 50 parts of water i , . . . . . .:
,. .: ~, , '. ' , ' '''~-'- " ' '. .

': `. ~ : ' , .

1CN68Z~5 HOE 75/F 036 was slowly added to the deep blue solution obtained, at a temperature of from 80 to 90C, in which process a p~ value of from 8 to 9 was established. The mixture was continued to be stirred for 1 hour in the boiling state, then the solu-t~on was ~iltelcu o~l from t~e precipitated calci-~m ~ulf~te and was then washed with 100 parts of warm water. The com-bined filtrate was passed over a column consisting of a commerc~al cation exchanger (H-form) and was then evaporated to dryness in the drying closet at a temperature of from 80 to 100C; subsequently it was pulverized. The product re-presented the free acid of the blue dyestuff.
The analysis showed an average content of 5.5 sulfo - groups in the molecule. The product yielded an ink having a very high tinctorial strength and a reddish blue color shade.
E Y. A M P ~ E 5:
If the 20% oleum used in Example 1 was replaced by a `` mixture of 32 parts of chlorosulfonic acid and 75 parts of ..i 100% sulfurlc acid, a blue dyestuff was obtained which had ~; an equally good quality.
According to the specifications given in Examples 1 through 5, the following dyestuffs could also be prepared, which also ylelded inks having a high tinctorial strength:
. ,~ .

. . .
, . .

J
:.
:'~ , ..

~' . , , .. . , , , ~ . .. . . , .... .. - . ,.
, , ~ .

_OE 75/F ~
106~Z~;S

ample Ik d~re~tuff C~l-r ~hade

6 ,~,I;H~ ~ E13i SO ~ blue ~ Cl l -(so3~4)4 . , ' ~
CH~

' _

7 ¢~ NH~3~ E~H~ + blue ,, , , ~, --(S03Na)4 ,'`~,1~ ' ' J~ ' .
` W`C1 -i~ 8 ,~ ._ 5 2 ~ C2H5_--SO3~ redd1sh blue (SO3H)4_5 ~ ~ .

.. . .. . .

HOE 7~/F 036 10~;8265 . .

Example Ink dyestuff Color shàde ~ CH3 ; CH3 . c ~ J - so ~ redd~sh blue (S03NH4)4_5 NX , CH
. , 3 ,. . .
NH ~ ..

C~30 ~ ~ ~ ~ C~3 ~ So30 ` NH _ -(S03K)4_5 ,' ' , ~ .
~.'' ~ ,. .' .
.. OC~3 ,:,'' ' ', .- .
, . .
- 11 3 CH3 -S03~ -- ,J~ NH~ ,~r~
CH3 -(S03H)4 reddish blue ~t ~ C~3 . C~3 , ~
i ~

~ ~ .

.~

.., ~ 1068Z~iS

Example Ink dyestuff Color shade CH3 ~ ~ C ~ 0~ CH3~ 3 bluish violet ¢~ ~ (S03H) 4 ,'.' _ 14 ~NH ~ NH ~ ~ 3 reddish blue .
,''',~
? NH

,. ~ CH3 _ ~!.
i'l, ~f _ Q

~A 15 ~,NH~3~ J3~NH ~ tS03H)3_4 Cl ~ Cl ~tl NH2 '~:

. { -- l 5 :, ~

:. , . : : ,, : , . ,.;: " : .

lC~682~ 5 Exa~ple dyestuff Color ~hade - -~ ~g ~ r 1 t ~3~ gr I b b OCN3 ~ . OCH3 - (S03N(CH3)3~)4 '' ''' ~' '. '-`

OCH

.;` ClCl- `

~n~ -so ~
_ -(S03~1H4)4 reddish blue ': ' ~ .
NH' . -,; 1~1 C~3 _ 18 ~ H ~ ~ S030 _ -(S03Na)5-6 reddish blue $

; .. ~ .
rf ~

,. . .
'~ ':: ' ,~. , ,, . .. , . ., ... , ~ . ., , , . - . . . . . .

HOE 75/~ 0~

E X A M P_~ E 19 - 50 Parts of a dyestuff prepared according to Example 1 - were dissol~ed in 50 parts of water, while slightly heating, in which process a concentrated dyestuff solution was obtain-ed which was fast to storag~
A blue writing ink having a very high tinctorial strength was obtained by diluting 2 parts of this concentrated solu-tion with 98 parts o~ water and by ad~usting the pH ~alue to 2.5 by adding sulfuric acid, which ink could be used for foun-tain pens having a metal tip.
E X A M P ~ E 20-.. . . . . . _ . . . . _ A blue writing ink which was fast to storage was obtain-ed by diluting 2 parts of a concentrated dyestuff solution ..
prepared according to Example 19 with 67.5 parts of water, ~0 parts of triethylene-glycol and 0.5 part of concentrated sulfuric acid, which ink could be used for fountain pens with metal tips as well as for fiber tip and felt tip pens.

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. -~,. . .

Claims

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

1. A compound of the general formula I

, wherein R1 stands for a hydrogen atom or for a lower alkyl or lower alkoxy radical, R2, R3 and R4 each represents a hydrogen or a halogen atom, a lower alkyl, lower alkoxy, phenyl, phenoxy, phenylamino, benzyl or phenethyl radical, or two of the radicals R2, R3 and R4, together with the benzene nucleus to which they are bound, represent a naphthyl or an anthraquinone radical, R5 stands for a hydrogen atom or the group , in which R2, R3 and R4 are defined as above, the radicals R1 to R4 are identical or different in each case, however at least one of the radicals R2 or R3 being other than hydrogen, A represents hydrogen, sodium, potassium, calcium or magnesium, an NH4 or N(R)4 group, wherein R stands for identical or different lower alkyl radicals optionally substituted by hydroxy or lower alkoxy radicals, or two radicals R together with the nitrogen atom form a piperdine or morpholine radical, and n stands for an integer of from 3 to 6.

2. A compound as claimed in claim 1, in which R1 stands for a hydrogen atom, R2 and R3 are different and represent hydrogen, chlorine or bromine atoms, lower alkyl or lower alkoxy radicals, and wherein at least one radical R2 or R3 is other than hydrogen, R4 stands for a hydrogen atom, A represents hydrogen, sodium, potassium or ammonium or an equivalent of calcium or magnesium, and n is an integer of from 3 to 6.

3. Process for the preparation of compounds as claimed in claim 1 or 2, which comprises sulfonating the corresponding triphenylmethane dyestuff bases or salts which are free from sulfo groups, by means of oleum or chlorosulfonic acid at a temperature in the range of from 40 to 120°C.

4. Process for the preparation of compounds as claimed in claim 1 or 2, which comprises sulfonating compounds of the formula 1, in which n is less than 3, by means of oleum or chlorosulfonic acid at a temperature of from about 40 to 120°C.

5. Writing inks which have a pH value of from 0.5 to 4 by adjustment with an inorganic or organic acid and contain from about 0.5 to 3% by weight of a highly sulfonated triphenylmethane dyestuff as claimed in claim 1 as well as, optionally, further additives.

6. Concentrated solutions of ink dyestuffs, which contain from 5 to 80%
by weight of one or several highly sulfonated triphenylmethane dyestuffs as claimed in claim 1, from 20 to 95% by weight of water as well as, optionally, additionally up to 30% by weight of organic solvents miscible with water, as well as, optionally, further additives.