DE1644408C3 - Process for the production of ethyl auramine - Google Patents

Description

The invention relates to improvements in the process for the preparation of "/ ithylauramin" and relates in particular to a process for the production of ethyl auramine of improved quality in increased form Yields in which the crude ethyl auramine obtained by various chemical processes is subjected to a basic treatment and an isolation process.

Auramine is a well-known dye that had considerable technical importance for many years. In more recently, for various reasons, e.g. B. because of concerns about the use of auramine as a coloring agent for paper used for food packaging, the ethyl homologue of auramine, which is hereinafter referred to as "ethylauramine", attained far greater importance.

It is well known that "ethylauramine" is chemically called M'-imidocarbonylbis ^ N-diethylaniline hydrochloride and represented by the following formula:

45

N (C ₂ H

N (C ₂ H ₅ J ₂

55

60

While numerous attempts have been made to improve methods applicable to auramine relatively little attention has been paid to the ethylauramine process. In general the procedures most commonly used for auramine are not for ethylamine so satisfying.

It has been shown, however, that a new method for auramine is also more useful for achieving it Bulging on Ethylauramine is applicable. This method, which is described in U.S. Patent 31 32 178 is a modification of previously known methods and involves the use of urea in the reaction mixture. Another improved process that uses sulfonamic acid and urea The reaction is described in U.S. Patent No. 3,268,585. The latter method is also applicable to ethyl auramine, the results are in terms of yield isolable product, however, not very satisfactory.

Because of the increased technical importance that ethylauramine has recently acquired, a urgent need to further increase the levels of usable ethylauramine product. It is true known that Äthylauramin arises in the above processes in significant amounts, part of the Ethyl auramine, however, is retained in the tarry residue that makes up the bulk of the product was removed. The amount of product that remains in the tarry residue is apparently in an insoluble form. With the isolation methods used up to now, it was not possible to to convert the insoluble form into usable soluble ethylauramine. As a result, the overall yield is inadequate in usable product. Yields of only 55 to 60% of theory are in isolable form available. It is evident that for economic reasons, improved yields are indicated usable product are highly desirable. The invention therefore aims at a new isolation process, by which the yield of usable ethyl auramine product is increased considerably.

The new isolation process according to the invention can be applied to processes for the production of Use Ethylauramin, which the implementation of Tetraäthyldiaminodiphenylmethan (also as "Ethylmethanbase" designated). Sulfur, urea and a source of ammonia such as ammonia gas itself. Ammonium chloride, ammonium acetate or ammonium sulfamate and then pouring into

include an aqueous bath. Heretofore, the solids were obtained by filtering those obtained after pouring Mixing and subsequent extraction of the solid filter material obtained with hot water isolated, leaving behind a tarry filter material. The hot water extracts then became after cooling the Äthylauramin gelallt, the precipitation expediently by adding sodium chloride and was sometimes promoted by inoculation material.

It has now been found that a considerably increased amount of the ethylauramine product of the aforesaid Process can be obtained by applying a new isolation process that through the novel combination of (a) an "base treatment" stage and (b) an "acid extraction" stage is marked. The new isolation process can be used either in conjunction with or to the exclusion of the hot water extraction of the solid Filter material (which is obtained from the mixture created during pouring), as previously carried out should be applied.

Thus, according to a preferred embodiment of the invention, the solid filter material that is obtained from the after the mixture obtained by pouring is isolated, first extracted with hot water as before, and the solid product is salted out from the extract. The new process is then carried out with the tarry filter material after the aqueous extraction remains behind. It is therefore advantageous to first borrow the isolatable product from the original Isolate the filter material and then the remaining tarry filter material, the base treatment and acid extraction stages subject to subsequent precipitation of the product.

According to another embodiment of the invention, the solid filter material, which is by filtering the obtained after pouring mixture obtained with an aqueous alkaline solution of Treated (i.e. washed or contacted) pH 10 or above and then diluted with a extracted aqueous acid solution. The acid solution is then treated to make the ethylauramine product precipitate, preferably by salting out with sodium chloride.

According to a further embodiment of the invention, instead of isolating the ethyl auramine product from the hot water extract of the filter material from the mixture obtained after pouring the extract combined with the acid extract used in the application of the base treatment and acid extraction stages and the product is then recovered from the combined extracts.

According to a further embodiment of the invention, the base treatment step is applied directly to the molten one Reaction mixture (color melt) applied, followed by the acid extraction stage. at In other words, this embodiment involves the usual pouring of the reaction mixture and the base treatment stage combined. In this case, the pouring medium consists of the alkaline one Solution instead of water. After filtering the mixture thus obtained, the acid extraction step is then carried out applied to the filter material formed and the entire recoverable Äthylauraminprodukt from dom Acid extract like.

It is believed that the treatment with the alkaline solution insoluble salts of ethyl auramine, z. B. decomposes the thiocyanate and the cyanurate. The acidic solution then makes the remaining one Dye base soluble. The dye can then be isolated from the acidic solution.

As indicated above, the crude dye product (i.e., reaction mixture can contain solid filter material or tarry filter material) to which the isolation method according to the invention can be applied, according to known processes can be obtained, for example by the process that involves the implementation of tetraethyldiaminodiphenylmethane, Includes sulfur, ammonium chloride and urea as described in Example 8 of U.S. Patent 3,132,178, or a method as it is for auramine using sulfamic acid and urea as it is in the U.S. Patent 32 68 585 is described. As indicated above, useful yields can be obtained Ethyl auramine by the method described in the latter patent for auramine by application the corresponding ethyl homologue of the starting methane base can be obtained. By application of the isolation process according to the invention, however, wi.d the yield of usable ethylaurimine greatly improved.

Another new and advantageous measure, by which the yield of Ethylauramin itself with Application of the known isolation process is improved, refers to the sulfamic acid process. when this is applied to ethylauramine. By applying the new method according to However, the invention improves the yield even further. This new measure consists in that one a gas is blown or passed through the reaction mixture during the reaction. Good results are achieved when ammonia is used as the "pass-through gas". When using the "pass-through gas" increases the yield of ethyl auramine when isolated by the original method sharply. One a corresponding increase in yield is achieved by the base treatment process according to the invention. The best results, however, are provided by a combination of the "gas transmission process" with the base treatment process. Normally, ammonia is used as a "pass-through gas" in the initial phase of the conversion. After using ammonia as a "pass-through gas" at the beginning, one can use carbon dioxide, nitrogen or other inert gases during of the end sections with equivalent results.

As stated above, the aqueous alkaline solution for the base treatment step is intended to be one Have a pH of at least 10. Sodium bicarbonate is not basic enough to be useful. In contrast, alkaline materials such as sodium carbonate solution, sodium hydroxide solution or ammonium hydroxide can be applied. With sodium bicarbonate there is a certain increase in yield but it is considerably less than when a more alkaline material is used.

Any water-soluble acids, either organic or inorganic, can be used for the acid extraction step. which form soluble salts with the ethyl auramine, but no decomposition of the product at the concentration used. Dilute lower alkanoic acids are preferred. For example, a solution is 10 parts Acetic acid in 2000 parts of water is particularly effective.

The parts and percentages given in the examples are units of weight.

example 1

Sulfamic acid process after the
U.S. Patent 32 68 585 using ammonia as the pass-through gas

A mixture of 124 parts of ethyl methane base (tetraethyldiaminodiphenyhnethane) and 300 parts of urea is heated to 120 ° C. with stirring in an anhydrous ammonia atmosphere. 39 parts of sulfamic acid are added and ammonia gas is passed through the entire mixture. The passage is continued during the reaction period up to the pouring stage described below. The mixture is then gradually (within V ₂ hours) heated to 155 ° C. and mixed with 26 parts of sulfur. After stirring for a further hour at the same temperature, a further sulfur content of 13 parts is added. After stirring for a further 2½ hours at 155 ° C., the temperature is gradually increased (over a period of 2 hours) to 175 ° C. and then kept at this value for _{2 hours.}

The entire molten mass is then in 7000 parts of water at 65 ° C, the 9 parts of acetic acid and contains 75 parts of filter aid. After stirring for 10 minutes at 65 to 67 ° C, the Solid isolated by vacuum filtration. The filter material is with 1000 parts of water from 65 to 67'C and then washed with 1000 parts of water at room temperature, an insoluble tarry material remaining. The mother liquors and the washing solutions are then with the addition of 700 parts of sodium chloride and 10 parts of dry ethylauramine combined as inoculum. After cooling to room temperature the deposited Äthylauraminprodukt is filtered off and dried. You get 105.7 parts dry dye product. Taking into account the 10 parts of the inoculation material used, the net dry product is 95.7 parts. Based on the analysis, this contains 94.2 parts or 62.2% of theory of the product, expressed as the monohydrate of the hydrochloride of Dye base (molecular weight 377.5).

The bfisen treatment stage will be with the remaining tarry material carried out from the water extraction of the original filter material. The tarry A mixture of 150 parts of 28% strength aqueous ammonia in 100 parts of water at room temperature is good washed, the washing solution six times through the tarry material within a time is passed through for 10 minutes. Then the good is used to remove alkali at room temperature washed with 2000 parts of water. These washing solutions are discarded. The rest of the good will then washed with 20 (K) parts of water at 65 to 70 C containing 10 parts of acetic acid, the Washing solution is circulated four times through the material. A final wash of the goods is carried out with 1000 parts of water at 65 ° C. are carried out. The combined washing solutions are then mixed with 300 parts Sodium chloride is added to salt out the product. The mixture is at room temperature cooled and the solid product is filtered off and dried. This second product fraction contains 22.6 parts of real dye or 14.9% of theory with the same Be / .ujisgrundlage as stated above.

Overall, the base treatment procedure results an increase in dye yield of 23.9%.

Dye (part% of theory

Main product
Secondary product

94.2

22.6

116.8

62.2
14.9

77.1%

The product yield thus increases from 62.2% to 77.1% or by 23.9%.

Example 2

Proportions of those prepared as described in Example I. molten reaction mixture containing crude ethyl auramine was subjected to the isolation and Base treatment process using several different alkaline washing solutions (A, 3 and C) subject. In all cases, dilute acetic acid was used as the acid wash solution.

A. 98.3 parts of the Farbscoffschmelze are poured into 1750 parts of water at 65 to 67 C, which contains 2 parts of acetic acid and 19 parts of filter aid. After stirring for 10 minutes, the solid material is filtered off. The filter material is washed with 250 parts of water at 65 to 67 ° C. and then with 250 parts of water at room temperature, a tarry residue remaining. The liquids and washing solutions are combined and mixed with 175 parts of sodium chloride and 2 parts of inoculum made from dry ethylauramine. After stirring and cooling to room temperature, all of the solids are filtered off and dried. 23.8 parts of dry dye are obtained (25.8 parts
2 parts inoculation material).

The tarry residue is further mixed with a solution of 40 parts of 28 to 30% strength aqueous ammonia and 25 parts of water, the washing solution being circulated for 10 minutes, and then further washed with water until no alkaline reaction occurs. These washing liquids will discarded.

The remaining tarry residue is then mixed with 250 parts of water at 65 ° C. and the 2.4 parts of acetic acid contains, washed, the washing solution being circulated four times. The washing liquid will with 80 parts of sodium chloride to precipitate the dye, which forms a dye slurry, offset. The dye is washed with a further 250 parts of water at 65 ° C., and this washing liquid is combined with the dye slurry. The entire slurry is then at room temperature cooled and the solid dye is filtered off and dried. 5.8 parts are obtained dry Dye. Analysis shows that the treated tarry residue still contains 2.3 parts of dye contains.

B and C. The above procedure is carried out with separate batches of the dye melt Use of sodium bicarbonate solution (Experiment B) and sodium carbonate solution (Experiment C) as alkaline washing material repeatedly. The results are shown in Table I.

Table 1

Bascnbchandlimg with 9K.3 parts l'aibsloffschmelze

Attempt Applied
Alkali wipes

Applied
Siiure laundry

Nctlugewiehl. l-'arbslofr- Aiisbeiile- Aiialyi. hesi. drier gewiclil / una line in the tar l-arbsloff remaining (icwichts- I. Ι · "ϋΙ1ιιημ 2. Filled Amount of real dye

iTcilel! parts)

1%)

(Parts)

25 parts of water

plus

40 parts of 2X% strength

ammonia

450 parts of water
plus

29.4 parts of sodium bicarbonate

275 parts of water
plus

18.5 parts of sodium carbonate

Example 3

250 parts of water 23.8

and

2.4 parts of acetic acid

250 parts of water 23.4

and

2.4 parts of acetic acid

250 parts of water 23.7

and

2.4 parts of acetic acid

5.8 24.6 2.3

2.6 11.1 5.85

4.2 17.7 4.4

A series of isolation concepts A, B and C are similar to Example 2 with different using 100 parts of dye melt alkaline agents for base treatment. The acetic acid wash solution obtained in the end however, it is combined with the hot water extract of the filter cake obtained after pouring the reaction mixture is obtained. In control experiment D, no base treatment is used. The results are shown in Table 11.

Table II

Base treatment with 100 parts of dye melt. Acetic acid wash solution with originally
aqueous washing solution

United Applied
search for .Mkaliwian

A ammonia solution

B sodium hydroxide solution

C sodium carbonate solution

D none

yield In the tar in real ver product more permanent more isolated anal. best. Parts more real dye (Parts) 28.4 3.9 28.4 1.9 26.8 5.0 23.3 8.0

Example 4

Basenbehandlimg the entire poured
Dye melt

121.3 parts of the ethylauramine dye melt (reaction mixture) are added to 2000 parts of water at 65 ° C containing 25 parts of filter aid. To With stirring for 10 minutes, 330 parts of water containing 6.75 parts of sodium hydroxide are added. After brief stirring at 65 ° C., a pH of 10.1 is determined.

The solid is filtered off, the material on the filter is washed free of alkali and the washing solution is discarded.

The filter material is then washed with 3000 parts of water at 65 ° C., its pH value with acetic acid is set to 3.4. After going through

4s the filter material is the pH of the washing solution with Acetic acid adjusted to 4.4, and the washing solution is then passed twice through the filter material. The final pH is 4.5. The filter material is finally washed with 600 parts of water at 65 ° C.

370 parts of sodium chloride are added to the combined washing solutions. The mixture is then cooled to room temperature, and the precipitated dye is filtered off and dried, whereby 28 parts of dye are obtained. Analysis shows that there was only 0.6 parts of dye in the filter lag behind.

Claims (4)

Patent claims: 1. Process for the preparation of ethyl auramine by reacting tetraethyldiaminodiphenylmethane with sulfur and ammonia in the presence of urea, pouring the resulting reaction mixture into water, filtering off the resulting precipitate, extracting the filter material with hot water and isolating the main part of the Äthylauraminprodukts from the filtrate, characterized in that one the filter material is treated with an aqueous alkaline solution with a pH value of at least 10, the filter material is then extracted with an acid solution and additional ethyl acetate • amine product isolated by salting out and filtration 2. Modification of the method according to claim 1, characterized in that the filter material treated directly with the aqueous alkaline solution and extracted with the acid solution. 3. The method according to claim 1 or 2, characterized in that the aqueous alkaline Solution aqueous ammonia, sodium carbonate or sodium hydroxide is used. 4. The method according to claim 1 or 2, characterized in that the acid solution is aqueous Acetic acid used.