DE2635852A1 - Process for the preparation of 4,4'-DIAMINOSTILBE-2,2'-DISULPHONIC ACID OR ITS ALKALINE SALT - Google Patents

Description

M 50 477

Registrants: Nippon Kayaku Kabushiki Kaisha New Kai jo Bldg., 2-1, 1-Chome, Marunouchi, Chiyoda-ku, Tokyo / Japan

.Process for the preparation of 4,4 ^l -diaminostilbene-2,2'-disulfonic acid or its alkali salts

The invention relates to a process for the preparation of 4,4 ^l -diaminostilbene-2,2 ^! -disulfonic acid (which is abbreviated as DAS in the following) or its alkali salts (which are abbreviated as DAS salts in the following) by catalytic hydrogenation of 4,4'-dinitrosostilbene-2,2 ^l -disulfonic acid (which is abbreviated as DNS in the following ) or their alkali salts (which are abbreviated as DNS salts in the following).

The process according to the invention is characterized in that a Raney nickel catalyst in the presence of dicyandiamide in water at a temperature in the range from 50 to 120 ^° C. and increased hydrogen pressure is used in the catalytic hydrogenation.

In the case of the DNS salts and DAS salts, "alkali" means Sodium or potassium. In recent years the following patent publications covering the manufacture of DAS and DAS salts concern, published. DAS and DAS salts have been produced by catalytic hydrogenation:

(1) in the presence of a noble metal catalyst (Japanese Patent Publication 815/1973);

(2) in the presence of Pd catalysts and iodine, bromine or their ions (Japan.Kokai 127 955/1974);

(3) in the presence of a Group 8 metal as a catalyst (DT-OS 2,320,416; Japan.Kokai 12059/1975);

(4) in the presence of MeSx as a catalyst, whereby

χ is an integer from 1 to 4 and Me is a metal of

7 0 9 8 0 8/116 p

Group 8 or Re means (Japanese Kokai 93927/1975);

(5) a cobalt catalyst (DT-OS 2,362,781; Japan.

Kokai 93953/1975);

(6) in alcohol as a solvent in the presence of a Nickel catalyst (DT-OS 2 455 394; Japanese Kokai 84550/1975);

(7) in the presence of a nickel catalyst and in aqueous solutions of phosphoric acid, boric acid, organic Acids or their salts as buffer materials at pH values of 5 to 10 (Japan.Kokai 84551/1975).

In the processes of these patents, noble metal catalysts for the hydrogenation are used in (1), (2), (3) and (4) used. The noble metal catalysts are more expensive than Raney nickel catalysts. It is very difficult to use the noble metal catalysts recover in high yield in industrial hydrogenations. This is for economic reasons However, reasons are important.

For comparison, the Raney nickel catalyst is cheap and well suited for industrial hydrogenation. In the method (3), Group 8 metals are used as catalysts for the hydrogenation of DNA salt. In Example 19, a Raney nickel catalyst is used for comparison. Unsatisfactory results are obtained because a large amount of 4,4 ^l -diaminodibenzyl-2,2'-disulfonic acid, which is hereinafter abbreviated as DABS, is formed as a by-product.

In (4), a high pressure is generally required for the hydrogenation. This is for industrial processes disadvantageous. In comparison 4c, Raney nickel is used, but the result is not satisfactory.

In (5) a cobalt catalyst is used; this is more expensive than Raney nickel. For hydrogenation are higher Temperatures and higher pressures required. This method is therefore not very advantageous.

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In (6), alcohol containing less than 3% water is used as the solvent. The use of alcohol with such a low water content results in an increase in the manufacturing cost as compared with a method using only water as a solvent.

Raney nickel is used in (7). However, there are higher temperatures required. The use of inorganic or organic buffer materials often requires complicated ones Treatments to clarify the waste water. Such treatments add to the cost of the hydrogenation process. The known processes for the hydrogenation of DNA or DNA salts in which Raney nickel catalysts are used thus give inadequate results, since DNA or DNA salt is simultaneously attached to the olefinic group with the nitro group Bond is reduced. This undesirable side reaction occurs very strongly in the case of Raney nickel catalysts.

According to the invention DAS or their DAS salts are in good yield by catalytic hydrogenation of DNA or DNS salt using a Raney nickel catalyst made in water in the presence of dicyandiamide.

According to the invention, the hydrogenation proceeds smoothly and the DABS salt is only a by-product in small amounts formed (less than 0.1% under suitable conditions). With knowledge of the known methods, this was surprising and has not been nearby.

DNA or DNA salt and dicyandiamide are available and can be used for the hydrogenation of the present invention. The hydrogenation according to the invention proceeds so smoothly and quickly that it can be used industrially. Is dicyandiamide preferably in an amount in the range from 0.5 to 50% on the weight of DNA or DNA salt used. Becomes dicyandiamide in an insufficient amount during hydrogenation are used, at the same time as the reduction of the nitro-

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groups the olefinic bonds of the DNA or the DNA salt are hydrogenated. The yield of DAS or DAS-SaIz is-almost quantitative and is 97.5 to 99.0 ^ the theoretical Yield.

The novel catalytic hydrogenation method of the present invention gives very good results when the following Conditions are met.

A certain amount of Raney nickel catalyst, suspended in water / water, is placed in a mixer equipped with a stirrer Given to autoclaves. The air in the autoclave is replaced with nitrogen and then with hydrogen. A increased hydrogen pressure is used.

The contents are stirred and warmed to the reaction temperature. A measured amount of dicyandiamide is added to the autoclave. (The dicyandiamide can be added before nitrogen is introduced.)

An aqueous solution of the DNS salt is introduced into the autoclave by a pump and the catalytic hydrogenation is carried out. The hydrogenation is conducted at a temperature in the range of 50 to 120 ⁰ C, preferably 55 to 90 ° C is performed. If the reaction is carried out at higher temperatures, the product is contaminated during the hydrogenation, since DABS or DABS salts or other by-products are formed in large quantities. If the hydrogenation is carried out at a temperature below 50 ^° C., the time which is required until the hydrogenation has ended is too long. In the present invention, the hydrogenation is carried out at an elevated hydrogen pressure. Although the hydrogenation can be carried out at a very high pressure, for example above 100 kg / cm (absolute), such a pressure is not necessary. It is generally carried out at a pressure in the range from atmospheric pressure to 50 kg / cm (abs.), Preferably at a pressure in the range from 5 to 31 kg / cm ² (abs.),

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• · _κ 2 6 3 b 8 5 2

-D-

carried out. It is preferred the rate of addition control of DNA or DNA salt so that essentially no DNA or no DNA salt in the autoclave during the Hydrogenation can be detected. Is DNA or DNA salt added faster than the rate of hydrogenation corresponds, they remain in the autoclave and accumulate, and the hydrogenation does not proceed smoothly and eventually stops on. After the supply of DNA or DNA salt is finished, the absorption of hydrogen ceases in a few minutes on. The reaction mixture is then cooled. The catalyst is separated off by methods known per se. The reaction product can be used without any further post-treatment be used as an intermediate for optical brighteners and dyes.

As explained above, the hydrogenation process according to the invention is carried out batchwise; however, it can can also be carried out continuously.

The following examples illustrate the invention. In the examples, mean DNA salt, DAS salt or DABS salt the corresponding sodium salts.

example 1

■ 0.6 g Raney nickel catalyst, slurried in Water (made from 1.5g alloy powder), 1.0g dicyandiamide and 100 ml of water are introduced into a 500 ml autoclave equipped with a stirrer. The lid is closed, air is replaced with nitrogen, and nitrogen is then replaced with hydrogen.

The hydrogen pressure is increased to 6 kg / cm ² (absolute), stirring is started and the temperature is increased to 60.degree. 140 g of the above aqueous solution of DNS salt are then continuously introduced into the autoclave by a pump over the course of 132 minutes. The temperature is maintained at 58 to 62 ° C. The hydrogen is introduced so that

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the pressure was maintained at 6 kg / cm (abs.) during the hydrogenation will. After the supply of DNA salt is stopped, hydrogen absorption stops within a few minutes.

The reaction mixture is stirred at the same temperature for 10 minutes and then cooled. You then hear with that Stir up. The hydrogen is replaced by nitrogen. The reaction mixture is separated from the catalyst and analyzed by liquid chromatography.

DABS-SaIz is only found in traces, which means that it is present in an amount below 0.1%. The rest consists mainly of-DAS-SaIz. The yield: an; THE ^ -SaIz is 97.8% of theory.

Example 2

0.6 g Raney nickel catalyst, slurried in Water (made from 1.5g alloy powder), 1.0g dicyandiamide and 100 ml of water are placed in a 500 ml autoclave as used in Example 1. The lid is closed and the air is replaced by hydrogen, as described in Example 1. The pressure is on

6 kg / cm (abs.) Increased. Man begin]
The temperature is increased to 78 ^° C.

6 kg / cm (abs.) Increased. You start stirring, and that

98 g of a 15.0% strength aqueous solution of DNS salt are continuously passed into the autoclave via a pump in the course of 87 minutes at a temperature between 78 and 82 ^° C. Hydrogen is introduced in such a way that the pressure is 6 kg / cm (abs.) is retained.

The absorption of hydrogen ceases within a few minutes after the addition of DNA salt is complete. The reaction mixture is stirred for 5 min at the same temperature, then ^{cooled to 45 °} C. and then the stirring is stopped. The hydrogen is released into the atmosphere

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let and then replaced with nitrogen. The reaction mixture is separated from the catalyst and replaced by liquid Analyzed by chromatography. The content of DABS-SaIz is 0.4% and the rest consists mainly of DAS-SaIz.

The yield of DAS salt is 97.5% of theory.

Example 3

0.6 g of Raney nickel catalyst, slurried in water (made from 1.5 g of alloy powder), 2.0 g of dicyandiamide and 100 ml of water are placed in the autoclave used in Example 1. In the same way as described in Example 2, the hydrogen pressure is increased to 6 kg / cm (abs.). One begins to stir and the temperature is raised to 80 ⁰ C. 100 g of a 15, above aqueous solution of DNS salt are continuously in the autoclave via a. Pump passed over 83 min at a temperature between 78 and 82 ° C.

Hydrogen is passed in such that a pressure of 6 kg / cm ² (absolute) is maintained during the hydrogenation. The reaction mixture is stirred for 5 minutes after the addition of DNS salt is complete. The autoclave is then cooled. The reaction mixture is analyzed, the content of DABS salt is 0.4% and the remainder consists mainly of DAS salt.

The yield of DAS salt is 97.5% of theory.

Example 4

0.6 g Raney nickel catalyst slurried in water (made from 1.5 g alloy powder), 1.0 g dicyandiamide and. 100 ml of water are added to the autoclave used in Example 1. In the same manner as described in Example 2, the pressure of hydrogen to 11 kg / cm ² is increased (abs.), One begins with the stirring and the temperature is raised to 80 ⁰ C.

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100 g of a 15% oxygenated solution of DNS salt are continuously passed into the autoclave for 74 minutes at a temperature between 78 and 82 ° C. Hydrogen is added in order to maintain the pressure at 11 kg / cm ² (abs.) During the hydrogenation. The mixture is stirred for 5 minutes after the addition of DNA salt is complete. The reaction mixture is then cooled. The reaction mixture is analyzed. The content of DABS-SaIz is 0.4% and the rest consists mainly of DAS-SaIz.

The yield of DAS salt is 97.5% of theory.

Comparative experiment 1

0.6 g of Raney nickel catalyst, slurried in water (made from 1.5 g of alloy powder) and 100 ml of water / volume are placed in the 500 ml autoclave used in Example 1. In the same manner as described in Example 1, the hydrogen pressure to 11 kg / cm (abs.) Is increased, starting with the stirring and the temperature is raised to 80 ⁰ C.

92 g of a 15.0% strength aqueous solution of DNS salt are continuously fed into the autoclave by a pump over the course of 90 minutes. The hydrogenation takes place at a pressure of 11 kg / cm (abs.) When the DNS salt has ended, the reaction mixture is ^{stirred for a further 5 min at 80 °} C. and then cooled. The reaction mixture is analyzed by liquid chromatography.

The content of DABS-SaIz is 13.7% and the content to DAS-SaIz is 86.3%.

Comparative experiment 2

0.6 g Raney nickel catalyst, slurried in water (made from 1.5 g alloy powder) and 100 ml water are used in the 500 ml car used in Example 1

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slave given. In the same manner as described in Example 1, the hydrogen pressure at 6 kg / cm (abs.) Is increased, starting with the stirring and the temperature is raised to 80 ⁰ C.

113 g of a 15.0% strength aqueous solution of DNS salt are continuously fed into the autoclave via a pump over a period of 90 minutes. The hydrogenation is carried out at a temperature · 78-82 ⁰ C. The absorption of the hydrogen stops a few minutes after the addition of the DNA salt is complete. The reaction mixture is stirred for a further 5 min at the reaction temperature and cooled. The reaction mixture is analyzed.

The content of DABS-SaIz is 6.7% and the content of DAS-SaIz is 93.3%.

B e i s ρ i e 1 5

1.0 g Raney nickel catalyst slurried in water (made from 2.5 g of alloy powder) and 100 ml of water are placed in the autoclave used in Example 1. The lid is closed, the air is replaced with nitrogen and then with hydrogen. The hydrogen pressure

is increased to 6 kg / cm (absolute). One begins to to stir temperature is increased to 60 ⁰ C. 0.16 g of dicyanamide, dissolved in 133 ml of the above aqueous solution of DNS salt (containing 20.0 g of DNS salt), are continuously introduced into the autoclave with a pump over the course of 146 minutes. The temperature is maintained at 58 to 62 ⁰ C. Hydrogen becomes so

directed that the pressure at 6 kg / cm (absolute) during the Hydrogenation is held.

After the supply of the DNA salt has ended, the absorption of the hydrogen stops within a few minutes. The reaction mixture is stirred for 10 min. At the same temperature and then cooled to 40 ⁰ C. You can hear

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the stirring. The hydrogen is released into the atmosphere and replaced with nitrogen. The reaction mixture is separated from the catalyst and analyzed by liquid chromatography. The DABS-SaIz content is 0.3%. Of the The rest is DAS-SaIz.

Examples 6 to 9

The amounts of Raney nickel catalyst listed in Table 1, 100 ml of water and the amounts of dicyandiamide given in Table 1 are used in Example 1 Given to autoclaves. The lid is closed and the air is replaced by hydrogen, as described in Example 1, replaced. The pressure is increased to 6 kg / cm (absolute). You start stirring. The temperature is set to the reaction temperature, which is given in Table 1 is increased.

133 ml of a 15% oxygenated aqueous solution of DNA salt are continuously fed into the autoclave via a pump and then hydrogenated. The temperature is set at the in Table 1 maintained temperatures. Hydrogen is introduced during the hydrogenation so that a pressure of 6 kg / cm (absolute) is maintained.

After the supply of the DNA salt has ended, the absorption of hydrogen ceases within a few minutes. The reaction mixture is stirred for a few minutes at the same temperature and then cooled to 40 ⁰ C. You stop stirring.

The hydrogen is released into the atmosphere and replaced with nitrogen. The reaction mixture is of the Separated catalyst and analyzed by liquid chromatography. The content of DABS-SaIz is in the following table listed. The yields of DAS-SaIz are almost quantitative.

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Ex. catalyst Dicyandiamide DNA salt 0 g Content of 6th 15.0 g 4.0 g 20, 0 DABS SaIz 7th 10.0 10.0 20, 3 0.3 8th 3.0 1.0 20, 2 0.6 9 6.0 2.0 20, 0.4 Ex. Reaction DNA salt to DNA salt 0.4 temperature driving time (min.) yield
% 6th 59-61 ⁰ C 29 98.7 7th 69-71 91 98.5 8th 59-61 90 98.8 9 59-61 41 98.8

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Claims (4)

PATENT CLAIMS: 1 J Process for the preparation of 4.4 ^t -diaminostilbene-2.2 ^l aisulphonic acid or its alkali metal salts, characterized in that 4.4 ^l -dinitrostilbene-2.2 ^I -disulphonic acid or its alkali metal salts in the presence of Raney nickel and Dicyandiamide catalytically hydrogenated in water at a temperature in the range from 50 to 120 ⁰ C and increased hydrogen pressure. 2. The method according to claim 1, characterized in that the amount of dicyandiamide 0.5 to 50 wt.%, ^{Based on the 4.4 t} -dinitrostilbene-2,2'-disulfonic acid or its alkali metal salts. 3 » Method according to claim 1 and / or 2, characterized in that a hydrogen pressure of atmospheric pressure to 50 kg / cm (abs.) Is used. 4. The method according to at least one of claims 1, 2 or 3, characterized in that the sodium salt is used ^{as the alkali salt of 4,4 '.- Dinitrostilbenr2j2 f -disulfonic acid.} 709808/1169