DE2648354A1 - ALKALINE AND ALKALINE SALT OF HEXAHYDROPYRIMIDINE-1,3-DIACETATE AND 5-HYDROXYHEXAHYDROPYRIMIDINE-1,3-DIACETATE - Google Patents

Description

UEXKÜLL S. SVOLBER «HAMBURG 52

BESELERSTRASSE 4

W. R. Grace & Co.

1114, Avenue of the Americas
New York, NY / V.St.A.

PATENT LAWYERS

DR. J.-D. FRHR. by UEXKÜLL DR. ULRICH GRAF STOLBERG DIPL.-ING. JÜRGEN SUCHANTKE

(Prio: November 11, 1975 and April 4, 197 6 US 630 791 and US 711 574

- 13504 -)
Hamburg, October 22, 197 6

Alkali and alkaline earth salts of hexahydropyrimidine-1,3-diacetate and 5-hydroxyhexahydropyrimidine-1,3-diacetate

The invention relates to new salts of the general formula

CH,

I '

Z-CH
I.
CH,

CH-COOM

I ^Z N

• N

CH ₂ COOM

in the M an alkali metal cation, for example sodium or potassium, 1/2 alkaline earth metal cation, for example barium, strontium or calcium, or an ammonium ion of the general formula

NO.

Q 'J 8 2 η / 1 0 4 7

represent where R .., R _0, R_ and R. are independently hydrogen, lower alkyl radicals having 1 to 7 carbon atoms or lower hydroxyalkyl, and Z is hydrogen or "the hydroxy group.

The salts according to the invention are suitable as starting materials for the production of chelating agents. You can in Acids of the general formula are converted:

CH - NH-CH "COOH 2 2

2-- CH

CH ₂ -NH-CH ₂ COOH

in which Z is hydrogen or the hydroxy group, i.e. in 1,3-propanediamine-N, N'-diacetic acid and 2-hydroxy-1,3-propanediamine-N, N'-diacetic acid, hereinafter referred to as PDDS and HYDROXY-PDDS.

The salts are available through three main methods:

A. From the corresponding nitriles by alkaline hydrolysis,

B. By reacting an acid of the general formula

CH - NHCH-COOH I ^Δ * Z-CH I CH ₂ -NHCH ₂ COOH

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in which Z is hydrogen or the hydroxyl group, with formaldehyde and

C. by reaction of a cyclic amine of the general formula

CH ₀ -NH I ² I Z-CH CH ₀

II ²

₂ - NH

with cyanide and formaldehyde under alkaline conditions.

The first method is to hydrolyze a nitrile of the general formula

CH ₂ CN

CH ₀ N

I «I

-CH CH, II ' CH ₀ N

CH ₂ CN

in an aqueous medium with an alkali metal hydroxide, for example sodium or potassium hydroxide or an alkaline earth metal hydroxide, with sodium hydroxide being preferred. In general, the molar ratio of nitrile to alkali metal hydroxide is 1: 2.2 to 2.4, in particular 1: 2.02 to 2.20, corresponding to a molar ratio of nitrile to alkaline earth metal hydroxide of 1: 1.1

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to 1.2, in particular from 1: 1.01 to 1.1. The hydrolysis takes place at about 95 to 110 C with excellent results. At temperatures above the normal boiling point, for example from 11O ⁰ C to 120 ° C of the reaction mixture, in which the hydrolysis takes place, a device can be used, which allows hydrolysis under overpressure. However, this is not necessary as excellent results are obtained at the normal boiling point of the mixture or below, for example at 90 to 100 ° C. The residence time in the hydrolysis zone is expediently 1 to 3 hours. In general, a residence time of 1.5 to 2 hours is preferred. The mixture in which the hydrolysis is taking place is advantageously heated until it is free of the ammonia formed as a by-product.

The nitriles used as starting materials can be prepared by mixing (a) 1,3-propanediamine or 1,3-diamino-2-propanol and (b) formaldehyde and either HCN or glycolonitrile (HOCH ₂ CN) in an aqueous medium .

Preferred molar ratios of amine to formaldehyde to HCN are 1: 3 to 3.5: 2 to 2.5, in particular 1: 3 to 3.1: 2 to 2.1, with molar ratios of glycolonitrile to formaldehyde of 2: 0.9 to 1.1 and especially from about 2: 1 and molar ratios from HCN or glycolonitrile to 1,3-propanediamine or 1,3-diamino-2-propanol from 2: 0.9 to 1.1 and especially from about 2: 1 are preferred.

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In general, it is advantageous if the mixture of amine, formaldehyde and HCN or glycolonitrile at 45 to 70.degree and in particular at 50 to 60 C and is kept at this temperature to form the nitrile. There were however, excellent results are also obtained when the mixture is prepared at 20 to 80 ° C and for the formation of the nitrile held at 40 to 60 ° C. The mixture is preferably held for 1 to 5 hours and in particular 2 to 3 hours to form the nitrile 4 hours at 50 to 60 ° C and in particular at 55 to 60 ° C.

Alternatively, the nitriles can be prepared by reacting in an aqueous medium (a) a compound of the general formula

CH ₀ -NH

I ² I
Z-CH

CH ₂ -NH

and (b) formaldehyde plus HCN or its equivalent, for example glycolonitrile which is formaldehyde plus on a mole to mole basis HCN, mixed. The starting materials themselves can be prepared by being in an aqueous medium 1,3-propanediamine or 1,3-diamino-2-propanol and formaldehyde mixed. (The starting material in which Z represents hydrogen is from Titherly et al. In J. Chem. Soc, 1913, volume 103, pages 330 to 340 on page 334.)

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Excellent results are obtained by using the amine and mixes the formaldehyde in a molar ratio of 1: 1 to 1.5 and in particular from 1: 1.0 to 1.05 and the mixture obtained about 1/4 to 16 hours and especially 1/2 to 1 hour at about 50 to 70 ° C and in particular at 55 to 65 ° C.

The cyclic compound, the formaldehyde and the HCN are preferably used in a molar ratio of from 1: 2.0 to 2.5: 2.0 to 2.5 and in particular from 1: 2.0 to 2.1: 2.0 to 2 , 1 mixed at about 45 to 70 C and especially at 50 to 60 C. The mixture obtained is then kept at 40 to 60 ° C. and in particular at 55 to 60 ^° C. for about 1 to 5 hours and in particular 2 to 4 hours to form the nitrile. Alternatively, the formaldehyde and HCN can be replaced by glycolonitrile.

The nitrile starting material, in which Z is hydrogen, can alternatively also be prepared by (a) a Tetrameres of 1,3-propanediamine and formaldehyde of the formula

H ₂ C CH,
H"

HC
2

^s c '

H,

A-

C ²

N N

¹ V

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CH

H, N — c '

H ₂ C _ CH, H.

CH

N 'N- ^CH 2

1 4

that according to Krässig, Makromol. Chem., 1956, Volume 17, Pages 77-130, especially pages 87/88 from formaldehyde and 1,3-propanediamine can be obtained, (b) formaldehyde and (c) HCN mixed and the mixture obtained on one to form the desired Nitrile holds suitable temperature. Preferred molar ratios of tetramer to formaldehyde to HCN are 1: 3.2 to 4.8: 7.2 to 8.8. Glycolonitrile, 1 mole of which corresponds to one mole of formaldehyde plus one mole of HCN, can be substituted on a mole-to-mole basis HCN plus formaldehyde can be used. A preferred reaction temperature is about 45 to 70 ° C., a preferred one Residence time about 20 to 90 minutes and especially 25 to 40 minutes.

The nitrile, in which Z represents the hydroxy group, can be replaced by using a tetramer of 1,3-diamino-2-propanol of the tetramer of 1,3-propanediamine (cf. the procedure below 17).

The second method of making the invention Salts consists in that in an aqueous medium a salt of the general formula

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NCH-COOM I.

H Z- CH

₂ NCH ₂ COOM

and formaldehyde mixed.

The third process for the preparation of the salts in which M is an alkali metal ion is generally, that an alkaline aqueous solution of an alkali metal hydroxide, preferably of sodium or potassium hydroxide and hexahydropyrimidine or 5-hydroxy-hexahydropyrimidine and an alkali metal cyanide, expediently sodium or potassium cyanide and aqueous formaldehyde in the alkaline aqueous Introduces solution, with stirring and the reaction mixture is kept at a temperature suitable for the evaporation of the formed Ammonia leads. The alkali metal cyanide and the formaldehyde are preferably fed in at such a rate that that there is an excess of unconverted cyanide in the reaction mixture over the unconverted formaldehyde. The alkali metal cyanide can be replaced by HCN and an approximately stoichiometrically equivalent amount of alkali metal hydroxide.

The implementation proceeds according to the following equation:

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/ J

+ 2MCN / y

N '
H

CH ₉ COOM

N + 2NH

3 CH ₂ COOM

in which M is an alkali metal ion, for example Na, K or Li, if an alkali metal cyanide is used.

In this regard, see US Pat. No. 2,407 which describes the preparation of alkali metal salts of Aminopolycarboxylic acids by reacting an aliphatic amine with formaldehyde and an alkali metal cyanide in alkaline aqueous medium is described.

According to a preferred embodiment, the alkali metal cyanide and the formaldehyde solution into the aqueous alkaline solution of the hexahydropyrimidine at such a rate containing reaction vessel led that in the reaction mixture compared to the unreacted formaldehyde, an excess of unreacted cyanide is present until one of the amine originally present in the alkaline aqueous solution (hexahydro-

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pyrimidine or 5-hydroxyhexahydropyrimidine) stoichiometric equivalent amount of alkali metal cyanide is supplied. Preferably, a reaction vessel with inlet openings, an outlet, a cooler, stirrers, and heaters are used.

The dialkali metal diacetate is preferably formed by that one introduces alkali metal cyanide or HCN and an aqueous formaldehyde solution into the alkaline aqueous solution, whereby one stirs and the reaction mixture is kept at a temperature which leads to the evaporation of the ammonia formed as a by-product.

The HCN, preferably liquid anhydrous HCN, or the alkali metal cyanide and the formaldehyde solution are preferred introduced into the vented reaction vessel at such a rate that the reaction mixture there is an excess of unconverted cyanide compared to the unconverted formaldehyde until the amount added Cyanide is stoichiometrically equivalent to the hexahydropyrimidine originally present in the first alkaline aqueous solution is.

When using alkali metal cyanide, since the alkali metal hydroxide is not a reactant, but at best provides alkali metal ions for the desired product (a dialkali metal acetate), for upright

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maintenance of strongly alkaline conditions used in the reaction mixture. Accordingly, the amount of hydroxide in the alkaline aqueous solution and thus in the reaction mixture can be varied over a wide range. In general however, a molar ratio of hexahydropyrimidine or 5-hydroxyhexahydropyrimidine to hydroxide of about 1: 0.1 is preferred to 0.4 in the alkaline aqueous solution.

On the other hand, when HCN is used, the alkali metal hydroxide acts (a) Alkalinity, according to the equation

HCN + MOH> MCN + H ₃ O

leads to the conversion of the HCN into an alkali metal cyanide; (b) provides alkali metal ions for the desired product (a dialkali metal diacetate) available and (c.1 maintains strongly alkaline conditions in the reaction mixture. In this In this case, the molar ratio of hexahydropyrimidine to alkali metal hydroxide is preferably about 1: 2.3 or 2.4 to 2.6.

In general, it is preferred to add the alkali metal hydroxide in the form of an aqueous solution, for example from 30 to 50% strength Sodium hydroxide or potassium hydroxide or of about 10% Lithium hydroxide to a saturated lithium hydroxide solution. However, it can also contain solid alkali metal hydroxide in the water or in the mixture of water and hexahydropyrimidine or 5-hydroxyhexahydropyrimidine be dissolved in the reaction vessel. In general

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fig

mean one prefers a weight ratio of hexahydropyrimidine or 5-hydroxy-hexahydropyrimidine to water from 1: 0.5 to 2 in the alkaline aqueous solution before the alkali metal cyanide and the formaldehyde are added, or from 1: 2 to 7 before the HCN is added, if the latter is used comes.

The formaldehyde is expediently added as an aqueous solution, preferably as an aqueous 30 to 50% formaldehyde solution. However, excellent results are also achieved with more or less concentrated formaldehyde solutions.

The alkali metal cyanide, if used, comes also advantageously as an aqueous solution for use, for example in the form of an approximately 25 to 35% strength alkali metal cyanide solution. But here, too, excellent results are achieved with more concentrated or more dilute alkali metal cyanide solutions achieved.

In general, continuous addition of the formaldehyde is preferred, although this is also added at intervals can. The alkali metal cyanide can also be added continuously or discontinuously. The best yields essentially pure. Dialkali metal diacetate will be in maintaining an excess of alkali metal cyanide or

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HCN compared to the formaldehyde in the reaction mixture obtained until the amount of alkali metal cyanide or HCN added to the amine is at least stoichiometrically equivalent.

Although excellent results using stoichiometric or slightly smaller amounts of alkali metal cyanide (or HCN). and formaldehyde can be obtained, is generally preferred the use of a small excess of these two reactants compared to the amine used. In general, preference is given to a molar ratio of amine to formaldehyde to alkali metal cyanide (or HCN) in the range from about 1: 2.1 to 2.3: 2.1 to 2.3.

The reaction is preferably at about 95 to 100 or 105 ° C carried out. However, very good results can also be obtained at temperatures of about 80 to 110 ° C. When the implementation is complete or substantially complete, it is advantageous to bring the reaction mixture containing the product a short time to boil, provided that it has not been heated to the boil during the implementation, in order to remove the last traces of the to remove ammonia formed as a by-product.

The reaction time, i.e. the time during which the formaldehyde and alkali metal cyanide (or HCN) solutions are added is generally about 2 to 8 hours.

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When the reaction is complete, concentration can be used to remove water and produce a more concentrated solution. The concentrated product solution can be recovered. If desired, however, the product solution can also be used in front of a concentration be won.

The reaction vessel is advantageous with heating and cooling devices Mistake. For example, a jacketed reaction vessel or a reaction vessel in which Inner cooling or heating coils are arranged. The same jacket and the can be used for heating and cooling same snakes are used. However, separate coils can also be used for heating and cooling. Further one can use a reaction vessel that is both jacketed and has snakes. In this case you can optionally Sheathing and / or coils can be used for heating and cooling, respectively.

If desired, the hexahydropyrimidine or the 5-hydroxyhexahydropyrimidine can be used prior to the formation of the above-mentioned alkaline aqueous solution in the one provided with an outlet Reaction vessel by converting 1,3-propanediamine or 1,3-diamino-2-propanol be prepared with formaldehyde in an aqueous reaction medium.

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As already stated, the salts according to the invention in PDDS and HYDROXY-PDDS can be converted. This can be achieved by placing the salt in an aqueous medium treated with a mineral acid or an acidic ion exchange resin according to the following equation:

CH ₂ COOM CH ₂ COOH CH ₂ COOH

N. HO

+ 2H ⁺ = ->

^N 'Z

I ι

CH ₂ COOM HNCH ₂ CH-CH ₂ NH +

Preferably 2.0 to 2.5 and especially 2.0 to 2.05 moles of a monoprotic acid or 1 to 1.25 and especially are used 1 to 1.02 moles of a diprotic acid are used per mole of salt. The preferred mineral acid is hydrochloric acid. When using a acidic ion exchange resin are advantageously 2 to 3 and in particular 2.2 to 2.6 equivalents of the acidic ion exchange resin per mole of salt is used.

One carries out the conversion of the salt into an acid with hydrogen chloride acid in an aqueous medium, it is often advantageous to add an excess of hydrochloric acid use, which is preferably added in the form of a concentrated, for example 33 to 40% aqueous solution the acid as the dihydrochloride of the formula

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CtI NCH-COOH

I.
II

Z- CH

NCH ₂ COOH

to precipitate - that is, the salt present as an aqueous solution is treated with such an amount of hydrochloric acid, that the acid is formed and in the form of the hydrochloride is precipitated. Excellent results have been obtained with 4 to 8, especially 4 to 6 moles of hydrochloric acid per mole of salt obtain.

The hydrochloride can preferably be in an aqueous medium with the stoichiometric amount of sodium (or potassium) bicarbonate, that is, 2 moles of carbonate per mole of hydrochloride can be converted into the free acid. For this conversion you can also use Ammonium carbonate, ammonium bicarbonate or ammonium carbamate can be used.

The free acid can also be extracted from the aqueous medium in which it is formed by adding a water-soluble alcohol, that is, an alcohol, including a diol or polyol, which is miscible or im-miscible with water in all proportions is essentially miscible, for example with methyl alcohol,

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Ethyl alcohol or isopropyl alcohol are precipitated. Excellent Results are obtained when the alcohol is added in an amount such that it is about 75 to 95% and especially 90 to 95% of the aqueous medium (after the acid has precipitated from it).

The corresponding sulfuric acid addition salts can be used in a completely analogous manner the formula

CH ₀ -NH-COOH
I ^Z
I - CH _{.U 0} SO.

getting produced.

In one embodiment, the overall process for the production of high quality PDDS proceeds according to the following reaction scheme:

+ 3 CH ₂ O + 2 HCN-

CH ₂ CN

CH ₂ CN

(Hexahydropyrimidine 1,3-diacetonitrile)

(HYPDAN)

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CH ₂ CN

+ 2 NaOH + 2 H_Q ²

CH ₂ CN

CH ₀ COONa j ^

N,

+ 2 H.

H ₂ O

CH ₂ COONa

CH _n COONa I ²

+ 2 NH,

CH ₂ COONa

(Disodium-hexahydrο-pyrimidine-1,3-diacetate)

(HYPDANa ₂ )

CH ₂ COOH CH ₂ COOH

HNCH ₂ CH ₂ CH ₂ NH + CH ₃ O + 2 Na

(PDDS)

An analogous reaction system applies to the production of the HYDROXY PDDS.

Methods for making PDDS are described by Johnson et al. in J. Org. Chem. 1962, volume 27, pages 2077-2080 (cf. in particular 2nd column on page 2079 and 1st column on page 2080).

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The method according to the invention for the production of PDDS represents represents a decisive improvement over the known processes. Among the advantages of the process according to the invention are to mention: (a) the PDDS becomes essentially free of by-products educated; (b) the by-products, NH-, formaldehyde and an alkali metal salt, for example sodium or potassium chloride or sulfate, are easily removed from the intermediate or final product with which they are formed; (c) less desirable materials such as anhydrous HCl and hydrogenation catalysts can be avoided and (d) that The end product is obtained essentially pure without the need for repetition in the costly and time-consuming manner as before must be decanted and crystallized.

The PDDS and HYDROXY-PDDS are suitable for the production of chelates with copper. These copper chelates are for control the concentration of copper ions in metal plating baths and the addition of copper to soil which is a copper deficiency aufwe is useful.

The PDDS and HYDROXY-PDDS are also suitable for the production of chelating compounds of the general formula:

CH ₂ COOH HHH

III CH ₀ -NCCCN-CH

² III

HZH

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in which Z = H or OH. These chelating compounds are particularly useful for chelating with iron (III) and (II). The chelating compounds, their preparation as well the production and use of iron chelates is described in the patent application (our no. 13 505),

referred to here.

The following examples illustrate the invention. Relate in them Unless otherwise noted, all parts are by weight.

example 1

74.1 g (1 mole) of 1,3-propanediamine was added to 50 ml of water in one Given reaction vessel. Then 68.2 g (1 mol) of 44% formaldehyde were added over the course of 40 minutes, the The temperature of the resulting mixture was kept at 50 to 70 ° C. The reaction mixture thus formed was cooled to 50.degree. Then 166.4 g of 68.5% glycolonitrile were within added from 50 minutes. The temperature of the reaction mixture increased during the first half of the glycolonitrile addition. It was cooled and then heated to maintain the temperature at 45 to 55 ° C. The clear, colorless solution was still 1 3/4 Stirred for hours and then left to stand overnight.

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When the straw-colored solution was stirred the next day, a mass of white crystals formed. This mass has been broken added to water, stirred and filtered. After slurries twice in 500 ml portions of water, it was collected Product dried at 45 to 50 ° C. 63.6 g of product (nitrile) were obtained, corresponding to a conversion (in one pass) of 38.3%.

A small sample of the nitrile produced in this way was analyzed The sample was titrated with perchloric acid in glacial acetic acid. A monoperchlorate salt formed on titration. The titration indicated a molecular weight of 164 (theory 164). The product was identified by gas chromatography and IR spectroscopy as essentially pure hexahydropyrimidine-1,3-diacetonitrile (HYPDAN) identifies:

CH,

2
I.
CH .r

CH
I. I.
N
ι Ah
I. I.
N
I. I.
CH ₂ CN 2 2 ^CN

Example 2

370.5 g (5 moles) of 1,3-propanediamine were added to 250 ml of water.

341.0 g of 44% strength formaldehyde were added to the aqueous amine solution

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added within 30 minutes, taking the temperature of the mixture formed held at 50 to 63 ° C. The mixture was then stirred for a further 40 minutes and left to stand overnight.

Then 832.0 g (10 moles) of 68.5% glycolonitrile were within added for 40 minutes. The temperature rose from 21 ° C. to 54 ° C. during the glycolonitrile addition. During half of this In addition, 275 ml of water were added. The resulting mixture was stirred for two hours at 50 to 57 C, whereby Crystals formed. Halfway through this time, another 250 ml of water were added. Then the reaction mixture became three Chilled to 23 ° C for hours and filtered. That in the form of crystals the product obtained was washed with 125 ml of water. When drying in air, 694 g of HYPDAN were obtained, correspondingly a conversion of 85%.

Example 3

74.1 g (1 mole) of 1,3-propanediamine was added to 50 ml of water. The aqueous amine solution was hot and reached a temperature of about 60 ⁰ C. was cooled to 50 ° C and added strength within 45 minutes with 68.2 g (1 mole) of 44% formaldehyde solution, wherein the temperature of the resulting mixture at 50 to 70 ⁰ C held. The mixture was then cooled to 47 ° C. and, within 50 minutes, with a mixture of 136.4 g (2 mol) of 44% strength formaldehyde solution and 84 ml (2.1 mol) of HCN

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(stabilized with 0.4 g of 85% H ₃ PO ₄ ) at a temperature of 15 C. The temperature of the reaction mixture rose with the addition of the formaldehyde and the HCN and reached a maximum of 65.degree. Within 2 minutes after the addition of the mixture was complete, white crystals of nitrile precipitated. The mixture with the precipitated crystals was stirred at 50 to 55 ° C. for two hours. It was then cooled to 25 ° C. and filtered. The nitrile crystals were washed with cold water. The nitrile obtained was dried at 50.degree. 138.5 g of product (HYPDAN) were obtained, corresponding to a conversion (in one pass) of 85%.

Example 4

148.2 g (2 moles) of 1,3-propanediamine were added to 100 ml of water. The aqueous amine solution was hot, reaching a temperature of about 6O ⁰ C. It was cooled to 23 ° C and added formaldehyde solution over 40 minutes with 136.4 g (2 moles) of 44%. The temperature of the reaction mixture rose to a maximum of 69 ° C. at the end of the formaldehyde addition. After stirring for 20 minutes, 275 g (4 mol) of 44% formaldehyde and 168 ml (4.3 mol) of hydrogen cyanide were simultaneously removed from separate containers over the course of 65 minutes added, keeping the temperature of the resulting mixture at 52 to 69 ° C. Two chills were required during the 65 minute addition. The reaction mixture was two hours

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stirred at 58 to 69 ° C, although the reaction was essentially complete after 1 1/2 hours, as the analysis showed. The product crystallized out of the reaction mixture during the 2 hour stirring when seeded with a small amount of HYPDAN. The slurry was cooled to 20 ° C. for 25 minutes and then centrifuged. The collected product was washed with 65 ml of water from a spray nozzle. Then the product became dried. 277 g (yield 84%) of HYPDAN crystals were obtained.

Example 5

246 g (1.5 moles) of the nitrile prepared in Example 2 were hydrolyzed with 552 g (3.2 mol) of 22.8% sodium hydroxide at about 100 to 106 ° C. The obtained mixture was at atmospheric pressure heated to boiling until substantially all of the ammonia formed as a by-product evaporates and a ammonia-free solution was obtained. This took about 1 1/4 hours. During this hydrolysis and heating to boiling water was added in such an amount that the volume of the system remained essentially constant. The final weight the very light straw-colored sodium salt solution was 851 g.

A small part of the ammonia-free solution produced in this way was analyzed, while the larger part was processed further became. When trying to titrate a small part of the ammonia-free solution with copper (II) chloride at pH 9, formed

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no copper (II) chelate. At pH 6.0, however, CH ^ O was released and the copper (II) ion was converted into a chelate. The sodium salt consisted of disodium hexahydropyrimidine-1,3-diacetate (HYPDANa ₂ )

CH ₂ COONa

CH COONa.

The titration of a weighed portion of the ammonia-free sodium salt solution with copper (II) chloride at pH 6 using a selective copper (II) electrode indicated that the conversion (in one pass) of HYPDAN to HYPDANa ₂ , based on the nitrile used, was 100 % of theory. Gas chromatography of the acidified, dried and silylated product (HYPDANa ₂ ) indicated that the HYPDANa ₂ was essentially free of impurities.

Example 6

The greater proportion of the HYPDANa ₃ solution prepared in Example 5 was diluted to 2 liters with water. The resulting aqueous system was acidified by passing it through a column containing about 2.6 equivalents (17% deficit) of Amberlite

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(strongly acidic cation exchange resin). A 900 ml fraction from pH 2.8 to 4.1 was collected at the bottom of the column. This product solution smelled strongly of formaldehyde, which was not the case with the original sodium salt solution. The fraction was evaporated. When it turned syrupy, it was mixed with methanol. A solid product precipitated. The precipitate was filtered off, washed with methanol and dried at 50.degree. An aqueous solution of the dried solid product formed a chelate at pH 9 (unequal to the original sodium salt solution) and at pH 6 with copper (II). Acid-base titrations, copper (II) titrations, gas chromatograms and IR spectrograms indicated that the solid consisted of 1,3-propanediamine-Ν, Ν ¹ -diacetic acid (PDDS).

CHz NCH ₀ COOH

² I ²

H
CH ₂

NCH ₂ COOH

The yield was 106.8 g of PDDS, that is, 37.5%. The remaining alkaline fractions were eluted with 1.5 liters of water.

The above alkaline fractions were passed through the same column after the resin was regenerated. A 700 ml fraction from pH 3.0 to 4.4 was collected and

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evaporated. Using the methanol precipitation method, PDDS was isolated. The yield here was 74.5 g PDDS or total 63.6%. In addition, a 1 liter fraction was eluted from pH to 11 by means of a dilute ammonia solution and collected.

Example 7

The resin of the column of Example 6 was obtained by Amberlite IRC (a weakly acidic exchange resin) replaced. The last 1 liter alkaline fraction obtained in Example 6 was through this new resin led. The Amberlite IRC 84 did not absorb the PDDS zwitterions as tightly as the Amberlite 200. The PDDS was eluted with distilled water. An 850 ml fraction from pH 3.4 to 4.4 was collected and evaporated. The PDDS was isolated as in Example 6.

Example 8

810 ml of concentrated hydrochloric acid (37.5% HCl) was added to 1000 g of 39.3% HYPDANa ₂ solution with stirring. White crystals precipitated which were identified as PDDS dihydrochloride.

CH ₅ NCH ₀ COOH

JL ι 2

II

.2HCl H

NCH ₂ COOH

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Example 9

The PDDS dihydrochloride of Example 8 was dissolved in 600 ml of water dissolved and brought to pH 3.8 with concentrated aqueous ammonia. The resulting PDDS / ammonium chloride solution (total 1250 ml) was mixed with 6 liters of methanol. It occurred to me white solid off. The mixture was stirred overnight. The precipitate was filtered off and with four liters for 3 hours Slurried methanol. The crystalline product was filtered off, washed with methanol and air dried. The yield was 203 g of 92.4% PDDS or 62%.

Example 10

39.2 g (0.2 mol) of 50% sulfuric acid and then 5 ml of concentrated (95.7%) sulfuric acid were added to 62.6 g (0.1 mol) of 39.3% HYPDANa _2. The resulting solution was allowed to stand for a few days to slowly evaporate. Crystals formed during this standing. The crystalline product was filtered off, washed with a small amount of water and dried at 50 ° C. The yield was 14.8 g of 97.3% PDDS sulfate, that is to say PDDS-H ₂ SO _{4 of} the formula

CHr NCH ₀ COOH

2 j 2

H
CH ₂ .H ₂ SO ₄

H
■ Ν

CH ₂ COOH
That corresponds to 50% of theory.

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Example 11

18.0 g (0.2 mol) of 1,3-diamino-2-propane »1 were placed in a reaction vessel and diluted to about 40 ml with water. Of the 13.8 g (0.2 mol) of 44% strength formaldehyde solution were added to aqueous amine solution at 30 to 70 ° C. over the course of 4 minutes. That The mixture thus formed was allowed to cool to 47 ° C. in the course of 15 minutes with stirring. Then it was gas chromatographed examined. The gas chromatogram indicated that the greater part of the mixture was not made up of 1,3-diamino-2-propanol, but consisted of a formaldehyde adduct of this compound, i.e. of 5-hydroxy-hexahydropyrimidine:

fr— \

HO CH CH ₀

II ²

CH N

H.

Example 12

The analyzed reaction mixture of Example 11 was continued reacted with 34.0 g (0.41 mol) of 68.5% glycolonitrile, which is added to the reaction vessel at 47 to 58 ° C. within 6 minutes added. The resulting mixture was heated to 45 to 55 ° C for nearly three hours and then cooled to 25 ° C. The final one The reaction mixture, a yellow solution, was gas chromatographed

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examined. The main component of this mixture consisted of 5-hydroxy-hexahydropyrimidine-i, 3-diacetonitrile (HYPDANOL):

CH ₂ CN

HO CH CH-

CHr

CH ₂ CN.

Example 13

The HYPDANOL obtained in Example 12 was 34.4 g (0.43 mol) 50% NaOH, which is diluted with about 100 ml of water from 99 to 1O5 ° C was saponified. The HYPDANOL solution was made in fractions added to the hot caustic alkali solution within 15 minutes. The obtained hydrolyzed mixture was at atmospheric pressure heated to boiling until essentially all of the by-product ammonia had evaporated, which was about 1 1/2 hours required. While heating to boiling, water was added to keep the volume constant. The final weight the yellow solution was 146.1 g.

A small portion of the ammonia-free solution so prepared was set aside for analysis. The greater part the solution was left for further processing into a very stable, iron-specific, chelating compound stand. When trying to get a small amount of the ammonia-free

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Titrating the solution with copper (II) chloride at pH 9 showed that this solution, like HYPDANa _9, did not lead to a chelation of copper (II). As with HYPDANa ₉ , however, CH ₂ O was released at pH 6.0 and the solution chelated copper (II). The sodium salt consisted of disodium 5-hydroxyhexahydropyrimidine-1,3-diacetate (HYPDA-OLNa ₉ ).

CH-COONa

CH- N

HO CH CH

CH ₂ N

CH ₂ COONa.

Titration of a weighed portion of this HYPDA-OLNa ₂ with cupric chloride at pH 6 using a selective cupric electrode indicated that the conversion (in one pass) of the 1 _/ 3-diamino-2-propanol to HYPDA-OLNa _{2 was} 96.7% of theory, based on the starting amine. The gas chromatogram of the acidified, dried and silylated product showed that the HYPDA-OLNa _{2 was} the main component of the hydrolysis reaction mixture.

Procedure 1

74.1 g (1 mol) of 1,3-propanediamine are added to 50 ml of water in one Given reaction vessel. The aqueous amine solution obtained becomes hot and reaches a temperature of about 60 C. This mixture

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is cooled to 50 ° C and within 1 1/2 hours with a mixture of 204.6 g (3 mol) of 44% formaldehyde and 84 ml (2.1 mol) of HCN (stabilized with 0.4 g of 85% H ₃ PO ₄ ) at a temperature of 15 ° C. The temperature of the mixture in the reaction vessel increases as the formaldehyde and HCN are added. The temperature may be allowed to reach a maximum of 70 ^0C. A few minutes after the end of the addition of the mixture, white crystals of the nitrile precipitate with an exothermic reaction. The mixture with the precipitated crystals is stirred at 60 to 70 ° C. for 2 hours. Then it is cooled to 25 ° C and filtered. The separated nitrile crystals are washed with cold water and then dried in the air or at 50.degree. About 138 g of product (HYPDAN) are obtained, corresponding to a conversion (in one pass) of 85%.

From the above examples and method 1 it can be seen that in the production of HYPDAN the glycolonitrile increases to moles Mole of base corresponds to 1 mole of formaldehyde plus 1 mole of HCN.

Procedure 2

The procedure of Example 5 is used to prepare other alkali metal and alkaline earth metal hexahydropyrimidine-1,3-diacetates applied by, when saponifying HYPDAN, the sodium hydroxide, for example, by the same number of Equivalents of potassium hydroxide, lithium hydroxide, barium hydroxide or calcium hydroxide.

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Procedure 3

The pH of the ammonia-free HYPDANa "solution prepared in Example 5 can be adjusted by adding concentrated hydrochloric acid (about 37.5% HCl) to be adjusted to 3.8.

The resulting solution is evaporated to give a slurry the larger proportion of sodium chloride in a PDDS / CH “O solution. The sodium chloride can be filtered off. The sodium chloride can be removed in this way as many times as necessary by alternate concentration and filtration will. The final filtrate is evaporated close to dryness and the residue is recrystallized from hot water / methanol, so that solid product precipitates on cooling. This product is filtered off, washed with methanol, recovered and dried. The solid obtained consists of PDDS, which contains a small amount of sodium chloride.

Procedure 4

The PDDS can be obtained from the solution of method 3 with a pH value of 3.8 by adding large amounts of methanol (10 times the Volume of the PDDS solution) to the PDDS / formaldehyde / sodium chloride solution be precipitated. The PDDS is filtered off, washed with methanol / water, collected and dried.

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Procedure 5

The reaction of a solution of 190 g (1 mol) PDDS with 80 g (2 mol) sodium hydroxide gives a first solution of "Disodium-1, S-propanediamine-NjN'-diacetate. By adding 68.2 g (1 mol) 44 % formaldehyde to this first solution gives a second solution of 246 g (1 mol) of HYPDANa ₂ .

Procedure 6

Various hexahydropyrimidine-1,3-diacetates of those given below Formula can be made according to General Procedure 5 by replacing the sodium hydroxide with the same number of equivalents another hydroxide can be produced:

CH;

CH,

CH,

CH ₀ COOM

I ²

-N

CH ₂

- N

CH ₂ COOM,

In this formula, M means an alkali metal ion, 1/2 alkaline earth metal ion or an ammonium ion of the general formula

-N-

R /

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in which R ₁ , R 1, R 1 and R, independently of one another, represent hydrogen, lower alkyl groups or lower hydroxyalkyl groups.

Procedure 7

HYPDANOL can be made from the 1,3-diamino-2-propanol / formaldehyde mixture (prepared by the procedure of Example 11) using the general procedure of Example 12 but below Using the equivalent amount of formaldehyde and HCN instead of the glycolonitrile of Example 12 can be prepared.

Procedure 8

The HYPDANOL can also be obtained directly from 1,3-diamino-2-propanol and a formaldehyde / HCN mixture can be prepared according to general process 1, instead of the 1,3-propanediamine of method 1 1,3-diamino-2-propanol is used.

Procedure 9

The procedure of Example 13 can be used to prepare other alkali metal and alkaline earth metal 5-hydroxyhexahydropyrimidine-1,3-diacetates be applied when replacing the sodium hydroxide with the same number of equivalents of potassium hydroxide, Lithium hydroxide, barium hydroxide, calcium hydroxide and the like are replaced in the saponification of HYPDANOL.

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- vtr -

Procedure 10

The method of Example 6 or 7 can be used to acidify HYPDA-OLNa- and _{to isolate 1 f} 3-diamino-2-propanol-N ₇ N ¹ -diessxgic acid (HYDROXY-PDDS) therefrom.

CH ~ NCH -COOII

2, 2

HIGH

CH £ NCH ₂ COOH

Procedure 11

The procedure of Example 8 can be used to prepare HYDROXY PDDS dihydrochloride

CHr NCH-COOH

² I ²

HIGH

.2HCl

NCH ₂ COOH

can be applied. The HYDROXY-PDDS can be obtained therefrom by the method of Example 8.

Procedure 12

The procedure of Example 10 can be used for the preparation of HYDROXY-PDDS-SuIfat can be applied.

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HO-

-CH

NCH ₀ COOH

I ²

H H

NCH ₂ COOH

Procedure 1 3

The reaction of a solution of 206 g (1 mol) of HYDROXY-PDDS with 40 g (1 mol) of sodium hydroxide results in a solution of the acidic HYDROXY PDDS monosodium salt. Other acid salts of 1,3-diamino-2-propanol-N, N'-diacetate of those given below Formula can be made by replacing the sodium hydroxide with an equal number of equivalents of another hydroxide will.

NCH ₂ COOH

HO

CH

NCH ₂ COOM ,

In this formula, M means an alkali metal ion, 1/2 alkaline earth metal ion or an ammonium ion of the general formula

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mean in the R, R ", R ₃ and R. are each independently hydrogen, lower alkyl groups or lower hydroxyalkyl groups.

Procedure 14

The implementation of a solution of 206 g (1 mol) of HYDROXY-PDDS with 80 g (2 mol) of sodium hydroxide result in a solution of disodium-HYDROXY-PDDS. By adding 68.2 g (1 mol) of 44% formaldehyde a solution of 262 g (1 mol) of HYPDA-OLNa “is obtained.

HO

CH

-CH

CH-COONa

I * -N

CH,

CH ₂ 1

CH ₂ COONa

Procedure 1 5

Various 1,3-diamino-2-propanol-N, N'-diacetate and various 5-Hydroxy-hexahydropyrimidine-1,3-diacetate the below given formulas can be according to the procedure of example 14 can be made by replacing the sodium hydroxide with an equal number of equivalents of another hydroxide:

CH,

HO CH

CH;

-NCH-COOM

I ²

NCH ₂ COOM

and

CH;

HO CH

CH-COOM

CH-

I ²

-N

CH ₂ COOM,

M has the meaning given in method 13.

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Procedure 16

This procedure illustrates the production of

CH;

CH.

CH-

CH ₂ CN

9 ^H 2

-N

by implementing according to the equation

+ 8HCN

N Ή — CH.

CH ₂ CN (HYPDAN)

Here means

N N-CH.

a tetramer

from 1,3-propanediamine and formaldehyde, which is used as a starting material will.

98.0 g (0.25 mol) of this tetramer from 1,3-propanediamine and CH “O are suspended in 125 ml of water. To do this, within 42 ml (1.05 mol) of HCN at 25 to 55 ° C. were added over a period of 30 minutes. The mixture obtained is kept at 50 to 55 ° C for 30 minutes, until most of the amine has dissolved. Then within

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a mixture of 68.2 g (1.0 mol) of 44% CH ₂ O and 42 ml (1.05 mol) of HCN, stabilized with 0.2 g of 85% H ₃ PO _{4, was} added over a period of 30 minutes (maximum temperature 65%) ° C). Within a few minutes after the addition was complete, white crystals of the nitrile precipitate. The slurry is stirred for two hours at 50 to 55 ° C and then cooled to 25 ° C, filtered, washed with water and dried at 50 ° C. About 138 g (yield 85%) of HYPDAN are obtained.

Procedure 17
This connection

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the present as

-CH.

is reproduced, can according to the general method of Krässig in Makromol, formerly., 1956, Volume 17, pages 77-130 and particularly pages 87-88, this general procedure being modified by the fact that the 1,3-propanediamine according to Krässig due to the equimolar amount 1,3-diamino-2-propanol replaced.

Procedure 18

General Procedure 16 is used to make HYPDANOL applied, with the

N-CH,

of procedure 16

-CH.

is replaced, which can be produced by method 17.

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Procedure 1 9

A first aqueous solution is made by mixing 1 mole of hexahydropyrimidine, about 140 g of water and 16 g of an aqueous 50% sodium hydroxide solution (0.2 mol NaOH) prepared.

308 g of an aqueous 35% strength sodium cyanide solution (2.2 mol NaCN) are divided into 10 equal parts and one of these parts is combined with the first aqueous solution to form a second aqueous solution.

The second aqueous solution is in a reaction vessel that with a reflux condenser, stirring and heating devices and inlet ports is provided, heated to about 80 ° C.

150 g of an aqueous 44% formaldehyde solution (2.2 mol HCHO) are added to the second aqueous solution at a rate of about 38 to 40 ml per hour, with (a) stirring and (b) the temperature of the mixture is maintained at about 80 ° C.

The remaining 9 parts of the aqueous 35% NaCN solution are added to the reaction mixture at intervals of about 22 to 24 minutes so that an excess of NaCN versus the HCHO until the amount of NaCN added is stoichiometrically equivalent to the hexahydropyrimidine.

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The reflux condenser can be removed after about the Half of the sodium cyanide solution is added. The temperature the reaction mixture can be brought to the boiling point and the mixture can be heated to boiling to remove it to ease the last traces of ammonia formed as a by-product and excess water to achieve a Remove solution containing about 40% disodium hexahydropyrimidine-1,3-diacetate contains. The conversion in one pass is about 95% of theory, based on the hexahydropyrimidine introduced .

The method 19 can be modified in such a way that the formaldehyde solution and the alkali metal cyanide in one admits such a rate that there is no excess of cyanide over the HCHO in the reaction mixture during the reaction is present. In this case, however, are the conversion (in one pass) and purity of the dialkali metal diacetate salt desired a little less.

Procedure 20

The general procedure 19 is repeated with the sodium cyanide is added continuously and not at intervals. When using this method, the sodium cyanide becomes with such Rate added that there is an excess of sodium cyanide over the formaldehyde, up to at least about 2 moles

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NaCN are added per mole of hexahydropyrimidine. The transformation is essentially the same as method 19.

The method 20 can be modified in such a way that the formaldehyde solution and the alkali metal cyanide in Speeds admits that there is no excess of cyanide over the HCHO in the reaction mixture. When applying this Modification. Are the conversion (in one pass) and the Purity of the desired dialkali metal diacetate salt somewhat lower than in process 20.

Procedure 21

By mixing 1 mole of hexahydropyrimidine, about 340 g of water and 192 g of an aqueous 50% sodium hydroxide solution (2.4 Mol NaOH) in a reaction vessel with inlet openings, a reflux condenser, stirring and heating devices is provided, a first aqueous solution is prepared.

The temperature of the first aqueous solution is set to about 50 ° C., if it has not already reached this temperature, and sufficient HCN is added, preferably in the form of liquid anhydrous HCN, although anhydrous HCN vapor is also added or aqueous HCN solutions can be used to bring the formed second aqueous solution to its boiling point.

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150 g of an aqueous 44% formaldehyde solution (2.2 mol HCHO) are added to the second aqueous solution at a rate of about 38 to 40 ml per hour while (a) stirring and (b) maintaining the temperature of the reaction mixture at the boiling point.

Then at intervals of about 22 to 24 minutes in essentially equal proportions of HCN are added until a total of 59.5 g (2.2 mol) of HCN have been added, so that a Excess of HCN over the HCHO is present until the amount of HCN added is stoichiometrically equivalent to the hexahydropyrimidine.

The reflux condenser can be removed after about half (1.1 moles) of the HCN has been added. The temperature of the reaction mixture can, if necessary, by heating from the outside, brought to boiling point and the mixture heated to the boil to remove the last amount of the by-product ammonia formed. to facilitate and remove excess water to form a solution containing about 40% disodium hexahydropyrimidine-1,3-diacetate contains. The conversion (in one pass) is about 95% of theory based on the hexahydropyrimidine used.

The method 21 can be modified in such a way that the formaldehyde solution and the HCN are processed at such a rate

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admits that no excess of cyanide over the HCHO is maintained in the reaction mixture. This modification leads to an approximately lower conversion (in one purchase) and purity of the desired dialkali metal diacetate salt than the method 21.

Procedure 22

General Process 21 is modified to include the HCN continuously rather than as in Process 19 in FIG At intervals. When using this method, the HCN is added at such a rate that the reaction mixture there is an excess of HCN over the formaldehyde until at least about 2 moles of HCN per mole of hexahydropyrimidine are added are. The conversion is essentially the same as in Method 21.

Process 22 can be modified by adding the formaldehyde solution and HCN at rates that there is no excess cyanide compared to the HCHO during the reaction. This modification leads to a slightly smaller one Conversion (in one pass) and purity of the desired dialkali metal diacetate salt as Method 22.

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Procedure 23

The disodium 5-hydroxyhexahydropyrimidine-1,3-diacetate can according to general procedures 19, 20, 21 or 22, the hexahydropyrimidine being prepared on a mole-to-mole basis 5-hydroxyhexahydropyrimidine is replaced. The conversion is about 95% of theory, based on the 5-hydroxyhexahydropyrimidine used.

Process 23 can be modified by adding the formaldehyde solution and the alkali metal cyanide (or HCN) in Speeds admits that there is no excess cyanide over the HCHO during the reaction in the reaction mixture. This modification results in somewhat lower conversion (in one pass) and purity of the dialkali metal diacetate salt than the procedure 23.

In method 19, 20, 21, 22 or 23, the sodium hydroxide be replaced by potassium hydroxide solution or a nearly saturated lithium hydroxide solution. Instead of the sodium cyanide Potassium cyanide or lithium cyanide can also be used.

The products manufactured according to processes 19 to 23, Disodium-hexahydropyrimidine-1,3-diacetate and disodium-5-hydroxy-hexahydropyrimidine-1,3-diacetate can be identified as follows:

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1. Titration with copper (II) chloride solution at pH 6.

2. At pH 9, the products do not chelate copper (II) ions.

3. Gas chromatography of the products after they have been acidified to pH 6 or lower, dried and silylated became.

A strong formaldehyde odor is noted when the products of procedures 19-23 are brought to a pH of about 6 or lower can be acidified. The following reaction occurs:

, COONa CH; NCH ₀ COOH

CH ₂ N

X-CH CH ₀ + 2H +> X-CH + HCHO

II
CH "N

H ₂ COONa CH ₂ NCH ₂ COOH

where X = H or OH.

In Processes 21 and 22, as well as portions of Process 23, the alkali metal cyanide (MCN) can be passed through on a mole to mole basis HCN will be replaced, that is, there will be 1 mole of HCN for 1 mole

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Alkali metal cyanide used. Doing this, for example, procedures 21 and 22 and parts of the procedure 23, about 1 mole of alkali metal hydroxide is provided per mole of HCN supplied.

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Claims (1)

-SlC- Claims Salts of the general formula CH, f ' Z- CH »CH, CH ₂ COOM Zl -N CH ₂ COOM in which M is an alkali metal cation, 1/2 alkaline earth metal cation or an ammonium ion of the general formula π 4- N
I. denotes in which R ₁ , R 1, R, and R are independently hydrogen, lower alkyl groups or lower hydroxyalkyl groups and Z = H or OH. 2. Salt according to claim 1, characterized in that the alkali metal cation is sodium. 3. Disodium hexahydropyrimidine 1,3-diacetate. 4. Disodium 5-hydroxyhexahydropyrimidine-1,3-diacetate. 709820/1047 5. Process for the preparation of the compounds according to claim 1, characterized in that one is in an aqueous medium Nitrile of the general formula CH_CN ι «£ CH- ι 2 in which Z = H or OH, with an alkali metal or alkaline earth metal hydroxide, in particular sodium hydroxide treated. 6. The method according to claim 5, characterized in that the reaction is carried out at the boiling point. 7. The method according to claim 6, characterized in that the mixture is heated to the boil until the aqueous medium is substantially is free of ammonia. 8. The method according to claim 5 to 7, characterized in that a nitrile is used, which is obtained by mixing (a) formaldehyde, (b) HCN or glycolonitrile and (c) 1,3-propanediamine or 1,3-diamino-2-propanol and preferably heating to 45 to 70 ° C. 709820/1047 9. The method according to claim 5 to 7, characterized in that a nitrile is used, which is obtained by mixing Formaldehyde and HCN, or glycolonitrile with an imine of the general formula: -) Z-CH CH, ι ι CH., N ² I. in which Z = H or OH. 10. The method according to claim 9, characterized in that the imine of the formula CH ₀ N-II T ² ι HO CH CH ₀ II ² N-H by mixing (a) 1,3-diamino-2-propanol and (b) Formaldehyde was produced in an aqueous medium. 11. The method according to claim 5 to 7, characterized in that a nitrile is used, which is obtained by mixing Formaldehyde, HCN or glycolonitrile and a cyclic amine of the formula 709820/1047 N-CH, or N-CH. O H was produced. Process for the preparation of a salt according to Claims 1 to 4, characterized in that in an aqueous Medium a compound of the general formula NCH ₀ COOM CH. NCH ₂ COOM and formaldehyde mixed. 13. Process for the preparation of an alkali metal salt according to Claim 1 to 4, characterized in that one (a) Water, an alkali metal hydroxide, preferably sodium or potassium hydroxide, and hexahydropyrimidine or 5-hydroxyhexahydropyrimidine mixes and 703820/1047 (b) the alkaline aqueous solution is an alkali metal cyanide, preferably sodium or potassium cyanide, or HCN and one Adding aqueous formaldehyde solution, stirring at a temperature sufficient to remove the ammonia formed to evaporate, preferably at 80 to 110 C. 14. The method according to claim 13, characterized in that the alkali metal cyanide is supplied as an aqueous solution or the HCN as liquid anhydrous HCN. 15. The method according to claim 13 or 14, characterized in that that the alkali metal cyanide solution or the HCN is fed in continuously. 16. The method according to claim 13 to 15, characterized in that that the alkali metal cyanide or the HCN and the formaldehyde solution at such a rate in the reaction mixture that an excess of unreacted in this Cyanide is present against the unreacted formaldehyde until an amount of cyanide is added that corresponds to the Hexahydropyrimidine originally present in the alkaline aqueous solution is stoichiometrically equivalent. 709820/1047 17. The method according to claim 13 to 16, characterized in that that step (a) is carried out in a reaction vessel which is provided with an outlet and inlet openings. 18. The method according to claim 13 to 17, characterized in that that when using HCN the molar ratio of hexahydropyrimidine to alkali metal hydroxide is 1: 2: 4 to 1: 2: 6. 19. Process for the preparation of an acid of general formula CH- NCH ₀ COOH ² I ² CH- NCH ₀ COOH in which Z = H or OH, or an acid addition salt this acid, characterized in that an alkali metal or alkaline earth metal salt according to claims 1 to 4 in an aqueous medium with a mineral acid, preferably hydrochloric acid or sulfuric acid or an acidic one Treated ion exchange resin. 20. The method according to claim 19, characterized in that you remove the acid from the aqueous medium by mixing 709820/1047 precipitates with methyl alcohol, ethyl alcohol or isopropyl alcohol. 21. The method according to claim 19 and 20, characterized in that that the hydrochloric acid is added in such an amount that a hydrochloride of the formula CH ₂ NCH ₂ COOH Z- CH .2HCl CH ₂ NCH ₂ COOH is precipitated, where Z = H or OH. 22. The method according to claim 19 and 20, characterized in that that the sulfuric acid is added in such an amount that a salt of the formula CH ₂ COOH Z- CH CH ₂ COOH is precipitated, in which Z = H or OH. 709820/1047 23. Compound of Formula CH, HIGH NCH ₀ COOH ! NCH ₂ COOH and their copper chelate. 24. Compound of Formula CH, Z- CH CH, NCH ₂ COOH H . 2HCl NCH ₂ COOH in which Z = H or OH. 25. Compound of Formula CH, Z- CH CH, NCH ₀ COOIl I ² II CH ₂ COOH in which Z = H or OH. 709820/1047 26. Compound of Formula CH ₂ ~ NH HO -CH CH, CH., N-H 27. Nitrile of the formula , CN CH ₂ - CII ₂ C Z-CH CH. II ' CH "-N CH ₂ CN in which Z = H or OH. 28. A method for producing the compound according to claim 26, characterized in that (a) 1,3-diamino-2-propanol and (b) formaldehyde are mixed in the aqueous medium. 29. Process for the preparation of the nitrile according to claim 27, characterized in that in an aqueous medium (a) Formaldehyde, (b) HCN or glycolonitrile, and (c) 1,3-propanediamine or 1,3-diamino-2-propanol mixed. 70982 0/1047 30. Process for the preparation of the nitrile according to claim 27, characterized in that formaldehyde and HCN, or Glycolonitrile with an amine of the formula CH, Z-CH CH, ■ N in which Z = H or OH, mixed. 31. Process for the preparation of the nitrile according to claim 27, characterized in that formaldehyde, HCN or Glycolonitrile, and a cyclic amine of the formula N N-CH, or J4 N N-CH, O H mixed. sch: kö 709820/1047