CH624926A5 - Process for removing copper (I) compounds from a reaction mixture, and application of the process - Google Patents

Description

The present invention relates to a process for removing copper-I compounds from a reaction mixture which contains water-insoluble organic compounds in a polar organic solvent. The process according to the invention makes it possible to obtain the water-insoluble organic compounds which are still contaminated in the reaction mixture with copper-I compounds which were used as catalysts or reactants in the preceding reaction in a copper-free state or practically copper-free state. The process according to the invention is particularly applicable to the production of copper-free cyan compounds or practically copper-free cyanine compounds which, by the action of copper-I-cyanide or copper-I-cyanide-forming compounds on water-insoluble aromatic halogen compounds, in particular o-haloazobenzene dyes, in polar organic solvents, preferably those which are able to dissolve copper-II compounds, were obtained.

The presence of copper salts in organic substances is known to be undesirable for many reasons.

This applies in particular to the above-mentioned cyanoazo dyes, which, if containing copper, can often not be used in a mixture with other metal ion-sensitive dyes, since the latter then tend to shift in color. Sometimes synthetic fibers that have been dyed with copper-containing dyes are damaged or a decrease in lightfastness is observed.

Several methods have already been proposed for removing the synthesis-related copper (I) compounds from organic substances.

For example, according to GB-PS 1 125 683 (= DOS

2 544 563) so that after the reaction carried out using copper (I) salt has ended, the organic reaction product precipitates together with the copper (I) salt, the filter cake is slurried with water, the copper (I ) salts are converted into water-soluble copper (II) salts by means of conventional oxidizing agents or into water-soluble complex compounds by means of conventional complexing agents, and finally the water-insoluble organic reaction product is separated off by filtration and washed free of copper.

In principle, the process according to US-PS is similar

3,772,268, but special complexing agents are used.

In addition to the mostly two-stage procedure, the known decoupling processes have the disadvantage that all of the copper ends up in the wastewater, from which it has to be separated by precipitation reactions due to its toxicity.

The aim of the present invention was to develop a process for removing copper-I compounds from a reaction mixture which does not have the disadvantages of previously known processes of this type.

Surprisingly, it has been found that the desired goals can be achieved by converting the copper-I compounds by oxidation into copper-II compounds which are soluble in the reaction medium which contains polar organic solvents and which in water-insoluble organic compounds contained in the reaction mixture can also crystallize out or precipitate out by adding a solvent, but with this precipitation the copper-II compounds still have to remain in solution.

The present invention therefore relates to a process for removing copper-I compounds from a reaction mixture which contains water-insoluble organic compounds in a polar organic solvent, which is characterized in that the reaction mixture is mixed with an oxidizing agent which the copper-I -Connections in copper ion compounds soluble in the reaction medium and the water-insoluble organic compounds crystallized from the reaction medium or precipitated by the addition of a solvent, but the solvent used must not lead to precipitation of the copper II compounds.

When carrying out the process according to the invention, an organic solvent is preferably used as the solvent for the precipitation of the water-insoluble organic compounds.

The polar organic solvent contained in the reaction mixture, in which the oxidation of the copper-I compounds to the copper-II compounds is carried out, is preferably one in which the copper-II compounds form soluble salts or soluble complexes. Preferred such solvents are a higher boiling alcohol e.g. with a boiling point of 100 to 200 ° C, preferably glycol monoalkyl ether.

Another preferred solvent used in the process according to the invention is an aprotic solvent, which is preferably selected from the following group of solvents:

carboxylic acid amides, dialkyl sulfoxides, tetramethylene sulfone, trialkyl phosphates and hexaalkyl phosphoric acid triamides optionally alkylated on nitrogen.

When carrying out the process according to the invention, iron III chloride is preferably used as the oxidizing agent which brings about the oxidation of the copper I compounds to the copper II compounds.

It is particularly advantageous to use a protic solvent, in particular a lower alcohol with 1-4 carbon atoms, as the solvent for the precipitation of the water-insoluble organic compounds when carrying out the process according to the invention.

Furthermore, the present invention relates to the application of the process according to the invention to a reaction mixture in which compounds of the following formula I are used as water-insoluble organic compounds

FROM

are included, in this formula I

A represents an aromatic-carbocyclic radical or a benz-isothiazole radical, the cyan substituents in these radicals being in the ortho position to group B if this represents a group of the formula —N = N-K,

B is a hydrogen atom, an alkyl, aryl, alkoxy, halogen, nitro, cyano, acylamino, phosphinimino, sulfonami-

5

10th

15

20th

25th

30th

35

40

45

50

55

60

65

624 926

4th

no, trifluoroalkyl, sulfonic, acyl, carboxylic acid ester, carboxylic acid amide or sulfonic acid amide group, or a group of the formula -N = NK, in which K is the remainder of a coupling component, and n is the number 1 or 2 stands,

and wherein in the reaction mixture the compounds of formula I were formed by a halogen-cyan exchange by the action of copper-I-cyanide or copper-I-cyanide-forming compounds on the corresponding halogen compounds.

In a preferred application according to the invention, the reaction mixture contains, as compounds of the formula I, those of the following formula II

Z

N = N-K

(Ii)

correspond in which

Y represents a hydrogen atom or a group which is one of the following formulas

-NO * -CN, —Rj, -OR], -CF3, -S02R „-S02N '| 2, -F,

K3

-Cl, -Br or —COR4, in which formulas R, represents a hydrogen atom or one of the following

Groupings -OH, -R1? -OR! or -N ^ 2, and

Ri represents an optionally substituted alkyl, aralkyl, or aryl radical, and

R2 and R3 are identical to or different from one another and denote hydrogen atoms or other substituents or

R2 and R3 together with the nitrogen atom to which they are attached form a heterocyclic ring,

Z represents a hydrogen atom or another substituent, the following being preferred as substituents:

a) -N02, -CN, -R „-OR !, -CF3, -S02Rx, -S02Nn r2 Ra '

V-

in which the radicals R4, Ri, R2 and R3 have the meaning given for Y, or

Z and Zj, when they are bonded to adjacent carbon atoms of the benzene nucleus, together and together with the carbon atoms to which they are bonded, can form a fused-on isothiazole ring and

K is the residue of a coupling component, preferably an N-substituted p-aminoarylene residue, and wherein the Verbin-10 fertilize the formula II in the reaction mixture in a halogen-cyan exchange by the action of copper-I-cyanide or copper-I-cyanide forming compounds were formed on the corresponding o-halogen azo dyes.

It is particularly advantageous to apply process 15 according to the invention to a reaction mixture in which the compounds of the formula II are those of the following formula III

CN

i \

N = N-K

-Cl, -Br and -COR4, in which the radicals R4, Rj, R2 and R3 have the meanings given for the radical Y, or b) heterocyclic radicals of the following formulas:

rb> w N-N / S

* 7

in which

R5 represents a hydrogen atom or a radical Ri, where Rj has the meanings given for the radical Y,

R6 for a methyl radical, and

R7 represents a group of the formula -C02CH3 or -C02C2H5, or

R6 and R7 together with the carbon atoms to which they are attached represent a fused-on benzene ring,

Z stands for a hydrogen atom or another substituent, the following groups being preferred by the substituents:

-N02, -CN, —Rj, -OR "-CF3, -S02Rl5 S02N" '/, -Cl,

-Br and COR4,

R,

(III)

correspond, wherein in this formula III Y, Zj have the same meaning as in formula II and K is the rest of a coupling component, and preferably that as defined in connection with formula II. In this preferred application, the compounds of the formula III were formed in the reaction mixture by a halogen-cyan exchange by the action of copper-I-cyanide or copper-I-cyanide-forming compounds on the corresponding 2,6-dihalogenozo dyes.

Examples of polar solvents which are contained in the reaction mixture from which the copper-I compounds have to be removed are those aprotic solvents which form salts or complexes soluble therein with copper-II compounds, such as, for example, the carboxylic acid amides which are mono- or bis-alkylated optionally on the nitrogen, furthermore lactams, dialkylsulfoxi-40 de, trilakyl phosphates and hexamethylphosphoric triamides. Examples include:

Dimethylformamide, dimethylacetamide, N-methylpyrrolidone, tetramethyl urea, dimethyl sulfoxide, tetramethylene sulfone, triethyl phosphate, hexamethyl phosphoric acid triamide. 45 Such soluble complexes between metal salts and carboxylic acid amides are e.g. known from German Ausleschrift 1 033 206.

Suitable oxidizing agents are trivalent iron salts such as e.g. Iron (III) chloride, bromide and sulfate, with iron (III) chloride being preferred for economic reasons.

Air or oxygen and peroxides of inorganic nature, such as e.g. Hydrogen peroxide or its complexes such as. B. perborates, these alone or in combination with kata-55 lytically active substances, such as. B. iron (II) salts can be used.

To accelerate and complete the reaction, it is preferable to work with a slight excess - in the order of up to 20% - of oxidizing agent, although only slightly higher copper values are obtained when equimolar amounts of iron (III) chloride are used. In addition, however, in some cases, especially in the presence of reducing substances, a large excess of oxidizing agent may be necessary. 65 The reaction temperature can be varied within wide limits. For reasons of easier handling, however, a temperature between 20 and 100 ° C. is preferred.

Suitable solvents for the precipitation of the organic

5

624 926

The reaction product is polar, especially highly volatile, organic solvents such as acetone and chloroform, but preferably protic polar solvents such as lower alcohols with 1-4 carbon atoms.

Water and aqueous acids are also suitable.

If the process according to the invention is applied to a reaction mixture in which compounds of the formula I given above are present as water-insoluble organic compounds, these may, for example, be dyes of azobenzene type Ia, for example those mentioned in British Patent No. 1 125 683 are. Preferred compounds of the formula I are those in which B represents a group of the formula -N = N-K, where K is the rest of a coupling component. These compounds therefore have the following formula Ia

example 1

500 ml of dimethylformamide, 277 g of 3-acetamido-4- (2'-bromo-4 ', 6'-dinitrophenylazo) -N, N-5 diethylaniline are added to a 2.5 liter sulfonation flask equipped with a stirrer, thermometer and reflux condenser and 19.7 g imidazole. The mixture is heated to 70 ° C. with stirring, 52 g of copper (I) cyanide are added and the mixture is heated to 105 ° C. The reaction is complete after 10 minutes. The mixture is allowed to cool to 75 ° C., then 11 methanol are added and the mixture is allowed to cool further to room temperature with stirring. 105 g io anhydrous iron (III) chloride are slowly added so that the temperature does not rise above 70 ° C. The reaction mixture is then stirred for a further 12 hours at room temperature. It is suctioned off, washed with 200 ml of methanol, with 500 ml of 10 percent. Hydrochloric acid and 41 water. The yield of dry dye is 215 g (87% of theory), the copper content 0.02%, the iron content 0.06%.

(CN)

n

A - N - N - K

Yes on. In the compounds of the formula I and also in the preferred compounds of this type which correspond to the above formula Ia, the radical A has the meaning given in connection with formula I, the aromatic carbocyclic radicals being those of the benzene and naphthalene series are particularly preferred.

The radicals A and K can also have further substituents customary in intermediates and azo dyes, such as halogen, alkyl, aralkyl, aryl, alkoxy, nitro, cyano, trifluoroalkyl, sulfone, acylamino, acyl , primary, secondary and tertiary amino, hydroxyl, carboxylic acid, sulfonic acid, carboxylic acid ester or optionally substituted carboxylic acid amide or sulfonic acid amide groups and heterocycles such as thiazolyl, thiadiazolyl and oxadiazolyl.

As already mentioned, the process according to the invention is particularly advantageously applicable to reaction mixtures which, as water-insoluble organic compounds, contain those which are of the formula II. III correspond. In this application, the following procedure proved to be particularly simple and advantageous: after the cyan exchange in dimethylformamide, the cyano group-containing compound of the formula II or III is precipitated with methanol, then the copper (I) is oxidized by adding iron (III) chloride and then sucks off the product containing cyano groups after washing with methanol, water and, if appropriate, dilute mineral acid.

The new process represents a decisive improvement because it enables very low-copper compounds containing cyano groups, in particular cyanazo dyes with a residual copper content of <0.1%, to be prepared in a one-pot process without intermediate insulation.

Example 2

In a 3 liter sulfonation flask with stirrer, thermometer 20 and reflux condenser, 297 g of 3-acetamido-4- (2 ', 6'-di-bromo-4-nitrophenylazo) -N, N-diethylaniline and 40.6 g of imidazole stirred in 700 ml of dimethylformamide. 105 g of copper (I) cyanide are then sprinkled in and the mixture is heated to 95 ° C. in 30 minutes. This temperature is kept under stirring for one hour, 25 is then allowed to cool to 80 ° C. and the dye is precipitated by adding 11 methanol. After further cooling to 35 ° C., 208 g of iron (III) chloride, sublimed, are added in portions with stirring, the temperature rising to 60 ° C. For homogenization, stirring is continued for a further 30 hours at 60-70 ° C. After cooling to room temperature, the dye is filtered off, well pressed and washed with 300 ml of methanol, then with 500 ml of water. After drying in vacuo, 200 g (85% of theory) of dye remain. The copper content is 0.1%, the iron content 0.08%. 35 If the procedure is analog or similar, the dyes and intermediates listed in the table below can be prepared in good yields with flaky copper and iron contents.

The second major advantage is often an improvement in the yield, which is probably due to a salting-out effect due to the high concentration of copper and iron salts.

Since precipitation of the cyano group-containing compound preferably with polar organic solvents, such as 45 methanol, all heavy metal salts and any excess cyanide remain dissolved in the organic phase. The solvent or solvent mixture, e.g. Dimethylformamide / methanol, which is obtained in the filtrate of the cyano group-containing compound, can then easily be recovered or separated by distillation. Thus there is another significant advantage that this process does not produce any toxic waste water containing heavy metals and cyanide.

Example No.

constitution

Cu content in%

Fe content in%

Oo

0.08

0.1

0.07

0.1

624 926

6

Example constitution Cu content Fe content

No.

XN

"CN

y = s \ c2h4oh

HNCOCHg

/ CPs m Ve in Ve

CN

/ - </ —v / cil-cil-cn

02N- (f y-N = N- / 'NVN 0.02 0.05

\ = / ^ CEj-CH-CHg

CN HNCOCHg lH ^

/ CN

/ - \ ^ 5

02N- / XVN = U - (/ M-N 0.1 0.09

v = / y = s ^ ca! -ch-oE2 CH H "0008» iH in

, CN

02N ^ N = N ^ N ^ <0.1 <0.1

'S ^ HNCOCHg 205

<0.1 <0.1

9 O2n ^ AN = N ^ VN "255 <0.1 <0.1

Vîj mrcocHg 2

CHg CHg

.CN „OCHg r ~ \ / - (/ c2h4 ° H

10 02N - (/ \ VN = N- ^ \ VN <0.1 <0.1

w ^ o2h4cn

\ HNCOCHg

H

CgHs fN / 7 ~ \

11 xvn <o, i <o, i

^ CbHB

HNCOCHg S02CHg

12 02N- / r> N = N- / r ^ V-N / '2 5 <0.1 <0.1

^ c = \ sj = - '^ c2 h5

nCN HNCOCHg

13 02N ^ N = N-S ^^ - N (C2H5) 2 <0.1

<0.1

cn

7

624 926

Example No.

constitution

Cu content in%

Fe content in%

14

, CN

° 2N- (Iy-N = N - ^) "N (C2H5) Î

<0.1

<0.1

15

16

17th

18th

19th

20th

H3C "^ ~ VN = 225

^ CN HtfC0C% OCOCBg5 \

O2N ^ _V = N - / ^ V) -N (C2H5) 2 \ CN HNC0-CH-C4 Brf

C2H5

CN CHg

02N ^ VN = N- ^ M-NHCK, CHj, OH

CN HNCOCHg .NO »

nhcho o2n - </ xVnhcho

<0.1

<0.1

<0.1

<0.1

<0.1

<0.1

<0.1

<0.1

<0.1

<0.1

<0.1

<0.1

21st

NC- ^ J ^ -CN

<0.1

<0.1

Example 22

6.3 g of copper powder are introduced into a solution of 23.5 g of 2-bromo-4-chloro-formanilide in 50 ml of dimethylformamide at 100 ° C. and the mixture is stirred for 10 hours at this temperature. Then allowed to cool, diluted with 100 ml of methanol and 18 g of anhydrous iron (III) chloride. You stir

Night at room temperature, the residue is filtered off and washed with cold, dilute hydrochloric acid and water. Copper-free (Cu <0.1%) 2,2'-55 di- (formylamino) -5,5'-diphenyl is obtained in 80% yield. In contrast, in the usual oxidative copper removal in hot hydrochloric acid with air, the formylamino group is saponified.

Claims (10)

624 926 2nd PATENT CLAIMS 1. A process for removing copper-I compounds from a reaction mixture which contains water-insoluble organic compounds in a polar organic solvent, characterized in that the reaction mixture is mixed with an oxidizing agent which the copper-I compounds in copper soluble in the reaction medium -fer-II compounds and allows the water-insoluble organic compounds to crystallize out of the reaction medium or precipitate out by adding a solvent, but the solvent used must not lead to precipitation of the copper-II compounds. 2. The method according to claim 1, characterized in that an organic solvent is used as the solvent for the precipitation of the water-insoluble organic compounds. 3. The method according to claim 1 or 2, characterized in that the polar organic solvent contained in the reaction mixture, in which the oxidation of the copper-fer-I compounds to the copper-II compounds is carried out, is one in which the Copper II compounds form soluble salts or soluble complexes. 4. The method according to claim 3, characterized in that the solvent used is a higher boiling alcohol, preferably glycol monoalkyl ether. 5. The method according to claim 3, characterized in that the solvent used is an aprotic solvent, which is preferably selected from the following group of solvents: optionally alkylated on the nitrogen carboxamides, dialkyl sulfoxides, t-tramethylene sulfone, trialkyl phosphates and hexaalkylphosphoric acid triamide. 6. The method according to claim 1 or 2, characterized in that iron-III-chloride is used as the oxidizing agent which causes the oxidation of the copper-I compounds to the copper-II compounds. 7. The method according to claim 1 or 2, characterized in that a protic solvent, in particular a lower alcohol having 1-4 carbon atoms, is used as the solvent for the precipitation of the water-insoluble organic compounds. 8. Application of the method according to claim I to a reaction mixture in which as water-insoluble organic compounds compounds of the following formula (CN) n A-B (I) are included, in this formula I A represents an aromatic-carbocyclic radical or a benz-isothiazole radical, the cyan substituents in these radicals being in the ortho-position to the group B if this represents a group of the formula —N = N — K, B is a hydrogen atom, an alkyl, aryl, alkoxy, halogen, nitro, cyano, acylamino, phosphinimino, sulfonamino, trifluoroalkyl, sulfone, acyl, carboxylic acid ester, carboxylic acid amide or sulfonic acid amide group, or a grouping of the formula -N = NK, in which K is the remainder of a coupling component, and n stands for the number 1 or 2, and where in the reaction mixture the compounds of the formula I are substituted by a halogen Cyan exchange was formed by the action of copper-I-cyanide or copper-I-cyanide-forming compounds on the corresponding halogen compounds. 9. Use according to claim 8, characterized in that the reaction mixture contains as compounds of the formula I those of the following formula II YiÄy.N = N-K CN (II) 10th correspond in which Y represents a hydrogen atom or a group which has one of the following formulas —N02, -CN, —Rj, -ORi, —CF3, -SÖ2R „-S02K ^ 2, -F, -Cl, -Br or -COR4, R3 being in these formulas R4 represents a hydrogen atom or one of the following 15 -Rz Groupings -OH, -Rl5 -ORj or -N 5-, and K3 Rj represents an optionally substituted alkyl, aralkyl, or aryl radical, and 20 R2 and R3 are identical to or different from one another and denote hydrogen atoms or other substituents, or R2 and R3 together with the nitrogen atom to which they are attached form a heterocyclic ring, 25 Z represents a hydrogen atom or another substituent, the following being preferred as substituents: a) -N02, -CN, -R1; —ORi, -CF3, -S02Ri, -S02 <* 2 K.3 30 -Cl, -Br and -COR4, in which the radicals R4, Rl5 R2 and R3 have the meanings given for the radical Y, or b) heterocyclic radicals of the following formulas: - "rj. R, ir-N AJl 6 in which R5 represents a hydrogen atom or a radical Rj, 40 where Rt has the meanings given for the radical Y, Re for a methyl residue, and R7 represents a group of the formula -C02CH3 or -C02C2H5, or 45 R6 and R7 together with the carbon atoms to which they are attached represent a fused-on benzene ring, Zj represents a hydrogen atom or another substituent, with the following groups of 50 substituents being preferred: -N02, -CN, -Ri, -OR ,, -CF3, -S02Rl5 -S02N'J, -Cl, R3 -Br and -COR4, in which the radicals R4, R], R2 and R3 have the meaning given for Y, or 55 Z and Zj when they are bonded to adjacent carbon atoms of the benzene nucleus, together and together with the carbon atoms which are bonded, can form a fused-on isothiazole ring and so K is the residue of a coupling component, preferably an N-substituted p-aminoarylene residue, and wherein the compounds of the formula II in the reaction mixture during a halogen-cyano exchange by the action of Copper-I-cyanide or copper-I-cyanide-forming compounds were formed on the corresponding 65-o-halo azo dyes. 10. Use according to claim 9, characterized in that the compounds of formula II contained in the reaction mixture have the following formula III 3rd 624 926 .cn (III) where Y, TLX and K are those in the claims and in the reaction mixture the compounds of the formula III by halogen-cyan exchange by the action of copper-I-cyanide or copper-I-cyanide-forming compounds on the corresponding 2, 6-Dihalogenazo dyes were formed.