MXPA98004789A - Stabilized hydroxylamine solutions - Google Patents

Abstract

The present invention relates to stabilized hydroxylamine solutions containing, as a stabilizer, at least one compound of the formula I. R1R2N-A-NR3R4, in which A and R1 to R4 are as defined in the description

Description

STABILIZED HYDROXYLAMINE SOLUTIONS The present invention relates to stabilized hydroxylamine solutions. Hydroxylamine, especially in the form of its salt with sulfuric acid, is an important intermediate for the chemical industry, and is widely used in chemical synthesis. It is often necessary to use hydroxylamine in the form of a solution of the free base, which is generally freed from a hydroxylammonium salt, such as, for example, hydroxylammonium sulfate or hydroxylammonium chloride, by the action of a suitable base. as ammonia, sodium hydroxide solution or an alcoholat ?. The neutral and alkaline hydroxylamine solutions are unstable and decompose to form ammonia, nitrogen nitrogen oxides and water, so that their transport or storage is highly problematic. The rate of decomposition increases with increasing temperature, raising the pH and raising the concentration of catalytically active impurities. To prevent the decomposition of hydroxylamine, a stabilizer is added to the solutions. Various stabilizers for hydroxylamine are known. The following proposals have been made: thioglycolic acid (JP-A-58069843), glycerol monoethers in hydroxyanthraquinones (DE-A-33 43 600), hydroxyquinolines (DE-A-33 45 734), polyhydroxyhexane-1,4-lactone (DE-A-33 45 733), anthocyanin (DE-A-33 47 260), hydroxyquinodines, flavones, benzonitrile, N-phenyl-N-hydroxythiourea (DE-A-36 01 803), flavan (DE-A- 33 43 599), thiosulfates, mercapto benzothiazoles, mercapto alkanols, mercapto thiazoline, thiuram disulfides, thioureas (EP-A-516 933), the tetrasodium salt of ethylenediamine tetra acetic acid, the trisodic salt of N-hydroxyethylethylenediamine tetra acetic acid, polyvinyl pyrrolidone or poly-N-vinyl-5-ethyl-2-oxazolidinone (US-A-3, 145, 082), amide oximes (US-A-3,480,391), hydroxamic acids (US-3, 480, 391), hydroxyureas (US-3,544,270), dipyridyl compounds (JP-A-58069842), aminoquinolines (JP-A-58069844), phenanthroline (JP-A-58069841), and polyhydroxyphenols (JP-A-4878099). However, none of the stabilizers proposed to date has been able to provide hydroxylamine solutions with sufficient stabilization so that no noticeable decomposition of the hydroxylamine occurs, especially during storage. Therefore, an object of the present invention is to provide a better means for stabilizing hydroxylamine solutions.

We have now found that this objective is achieved, surprisingly, by the use as a stabilizer of at least one compound of formula I: RVN-A-NRV (I) in which A is alkylene, alkenylene, alkynylene, cycloalkylene, cycloalkenylene, arylene, o-, m- or p-xylylene, a saturated or unsaturated 5- or 6-membered heterocycle having a nitrogen atom, the radicals being capable of containing 1, 2 or 3 substituents that are independently selected from alkyl, alkoxy, and hydroxyl, or is -X- [-NR-B -] -:? wherein B and X are CH ^ CH-- or - CH ^ CH ^ CH; -, n is 10-50,000, R is H, alkylene, ethylene or propylene which is substituted by OH, NH_, NHCOR5, or COOH, or is CSSH, CH? CN or CH2P03H_, or is a bridge to a nitrogen atom of another polyethylene imine or polypropylene imine chain, the bridge is formed by -X- [-NR-B-] - or CH ^ CHOH CH; - [ -O CH CH] - CH.CHOH CH; - wherein independently o and p are 1-15, R 5 is H, Cι-Cis alkyl or CHR 5 COR 6 where R 6 is C 2 -C 8 alkyl; R R3, and R4 independent of each other are H CH2COOH, CH2PO3H2, alkyl, acyl, CH2CH2OH, CH2CH2NH2 O wherein R7 is OH, SH; NHt, CN, COOH, alkyl 1 alkoxy, or the salts thereof, with the exceptions of ethylenediaminetetraacetic acid and N-hydroxyethylene diamido tetra acetic acid and salts thereof. The present invention further relates to stabilized hydroxylamine solutions containing hydroxylamine and at least one compound of formula I. The novel solutions comprise hydroxylamine in the form of the free base or a hydroxylamine salt at least partially neutralized; in other words, free hydroxylamine is mixed with the hydroxylamine salt. The stabilizers that are used according to the invention can be used to stabilize all types of hydroxylamine solutions. These can be aqueous solutions or hydroxylamine solutions in an organic solvent such as methanol, ethanol, N-propanol, isopropanol, acetone tetrahydrofuran, etc., or they can be mixtures of water and organic solvents. The stabilizers which are used according to the invention are also soluble in the solvents in which the hydroxylamine is soluble. If appropriate, the solubility can be obtained by choosing the appropriate R1-R4 and A groups. Hydroxylamine solutions are generally obtained by reacting a hydroxylammonium salt, especially hydroxylammonium sulfate, hydroxylammonium chloride and hydroxylammonium phosphate, with a suitable base, such as ammonia, sodium hydroxide, potassium hydroxide or calcium hydroxide. In the case of completing the neutralization of the hydroxylammonium salt, a solution is obtained comprising the free hydroxylamine and the salt derived from the base cation and the acid anion which are present in the hydroxylammonium salt. The salt can be completely or partially separated. The hydroxylammonium salt can also be neutralized only partially with the base. In this case, a solution is obtained comprising not only free hydroxylamine and the aforementioned salt but also unreacted hydroxylammonium salt. All these solutions can be stabilized according to the invention, the nature of the anion in the hydroxylammonium salt being not crucial. In the context of the present invention, the alkyl is a straight or branched chain radical preferably of 1 to 18 carbon atoms, especially of 1 to 6 carbon atoms and, in particular, of 1 to 4 carbon atoms. The same comments apply to the alkyl group in alkoxy. The alkylene is a divalent radical having a straight or branched chain, preferably having from 2 to 6 carbon atoms, especially from 2 to 4 carbon atoms. Alkenylene and alkynylene are branched or straight chain divalent radicals, preferably having 3 to 6 carbon atoms and, in particular, 3 or 4 carbon atoms. The alkylene and cycloalkenylene rings are preferably cyclopentylene or cyclohexylene or, respectively, cyclopentenylene or cyclohexenylene. The arylene is preferably an aromatic hydrocarbon radical of Cr. To Ci or phenylene. The saturated or unsaturated heterocycle is preferably pyrrolidinylene, piperidinylene, pyrrolylene or pyridinylene. The helocycle is attached by carbon atoms to the two nitrogen atoms of the formula I. The acyl is straight or branched chain and preferably has from 1 to 19 carbon atoms. A is preferably alkylene, cycloalkylene, arylene or -X - [- NR-B -] - r and in particular is alkylene cycloalkylene or -X - [- NR-B-] -, in this case the independent radicals R1 to R4 preferably, they are CH2COOH, CH2CH: OH, CH2CH2NH2, and in particular they are CH2COOH or R "preferably in the ortho position and in particular is OH, COOH or a branched alkyl radical (bulky), such as isopropyl, ter -butyl, etc. The stabilizers according to the invention can also be used in the form of salts.The particularly suitable salts are alkali metal salts, such as sodium salts or potassium salts, or ammonium salts, if they are present. present acid functions and acid addition salts with inorganic acids such as HF, HCl, HBr, HrSO ^, H-.PO, etc., if basic functions are present.Another preferred embodiment is a stabilized solution containing as a stabilizer a compound of the formula I in which A is alkylene or cycloalkylene and R a R "independent of each other is CH 2 CH 2 OH or wherein R 7 is as defined above and in particular is OH, SH or NH 4. If A is -X - [- NR-B -] - n, the compounds of the formula I are the polymers polyethylene imine or polypropylene imine, which are generally weakly refolded. The repeating units of the formula can be identical or different. This applies in particular when units that are substituted on the nitrogen atom are present, ie, R is different from hydrogen in at least some of the units. The degree of substitution chosen can be found within a wide range and is generally in the range from 5 to 98%. The slight crosslinking, which is the result of the preparation of the polyethyleneimines and polypropyleneimines, can be increased by polyether bridges between the polymers. The polyether bridge is formed by alkylating some of the nitrogen atoms with epichlorohydrin followed by ethoxylation. In the case of the polyethylene imine or polypropylene imine polymers, the radicals R to R4 are preferably H or alkyl. The average molecular weight of the polymers can be chosen within a wide range, and is generally in the range from 800 to 2,000,000, in particular from 1,000 to 1,500,000 and, in the case of more highly crosslinked polymers, in the range from 50,000 to 2,000,000. According to another preferred embodiment, the stabilized hydroxylamine solution comprises at least one compound of the formula I in which A is -X _ - [- NR-B-] - r ,, B and X are CH2CH: -, R is CH ^ COOH, CH2CH: C00H, CHCH2OH, CH: CH ~ NH_, NHCOR 'or CSSH or is a bridge as defined above, R5 is as defined above and R1 to R4 are H or alkyl. Particularly preferred compounds in this context are: a weakly cross-linked polyethyleneimine with an average molecular weight in the range from 1,000 to 2,000,000; carboxymethylated polyethyleneimines with a degree of substitution from 25 to 98% and an average molecular weight in the range of 1,500 to 1,500,000; carboxylated polyethyleneimines with a degree of substitution of 5 to 50% and an average molecular weight in the range of 1,000 to 1,500,000; partially amidated polyethylene imines (one or two of the radicals R "to R4 are acyl of C? ~ CI?) with a degree of substitution of 5 to 50% and an average molecular weight in the range from 1,000 to 1,500,000; crosslinked polyetherimines polyetherimines with an average molecular weight in the range from 50,000 to 1,500,000; hydrophobically modified polyethyleneimines (R = -CH2CH2NCORr, wherein R5 is CHR'5COR6 and R6 is Ci2 to C3 alkyl, especially hexadecyl) with a degree of substitution of 1; at 7% and an average molecular weight in the range of 1,500 to 1,500,000.These polymers are obtained by reacting the corresponding ethylene (R = CH2CH: NH with the corresponding alkyldytetenes; hydroxyethyl substituted polyethyleneimines with a degree of substitution from 80 to 100% a and ur average molecular weight in the range of 1 to 2,000,000; polyethylenimine dithiocarba atos (R = CSSH) with a degree of substitution from 30 to 60% and an average molecular weight from 2,000 to 1,000,000, and the sodium salts of these. Some of the above polyethyleneimines are commercially available and are marketed, for example, by BASF AG under the name LUPASOL®. According to another preferred embodiment, the stabilized hydroxylamine solution comprises as a stabilizer a compound of the formula I in which A is cyclohexylene or -CH 2 CH - and R 1 to R 4 are CH.COOH or wherein R-7 is OH, SH, NH_, or COOH Particularly preferably these compounds are: trans-1,2-diaminocyclohexan-N, N, N ', N'-tetraacetic acid and / or N, N'-di (2-) acid hydroxybenzyl) ethylenediamine-N, N'-diacetic and the salts thereof The compounds of the formula I are known and commercially available or can be prepared by analogy with the known methods. the compounds of formula I in an amount which is sufficient for stabilization, preferably containing from 0.001 to 20% by weight (from 10 to 2000,000 ppm), in particular from 0.001 to 10% by weight, particularly preferably from 0.01 to 5% by weight, very particularly preferably from 0.02 to 2% and n weight, of a compound of formula I, based on the hydroxylamine content. The concentration of hydroxylamine is, in general, 1-100% by weight, in particular 1-70% by weight, based on the total weight of the solution. The stabilizer can be added before or after the neutralization of the hydroxylamine salt, but preferably before neutralization. The compounds of the formula I are effective over a wide temperature range. For example, they stabilize hydroxylamine solutions from -20 ° C to 130 ° C, preferably at -10 ° C-100 ° C. However, these are also suitable as stabilizers at noticeably higher temperatures, under the pressures that are necessary to liquefy the solution. The following examples illustrate the invention without limiting it. The determination of the hydroxylamine concentrations that are carried out in the examples is done by redox titration.

Empies: 20 ml of an aqueous solution of hydroxylamine at 50% concentration were charged to a 50 ml round-bottom glass flask and 500 ppm (m / m) of the stabilizer of formula I, based on the mass of hydroxylamine, were added in each case. The flask was kept at room temperature or heated with an oil bath at 100 ° C and maintained at this temperature. The hydroxylamine contents of the solutions stabilized at ambient temperature and at 100 ° C were determined by redox titration after the defined periods. For this purpose, the defined amounts of the sample were removed from the solutions, boiled for 5 minutes with excess ammoniacal iron (III) salt solution in sulfuric acid and the iron (II) salt formed was titrated with Serious salt (IV), the end point was determined by potentiometer. Table 1 shows the results at room temperature while in Table 2 they are at 100 ° C. To demonstrate the outstanding stabilizing action of the compounds of the formula I in the hydroxylamine solutions, measurements with unstabilized hydroxylamine solutions and with hydroxylamine solutions stabilized using ethylene diamine tetra acetic acid (EDTA) are shown for comparison.

Table 1 room temperature Compound Time [d] Hydroxylamine content [%] Polyethyleneimine (not 27 48.1 substituted, branched, MW ~ 800) Polyethylenimine 30 47.7 (carboxylated, branched PM-1000) Polyethylenimine (carboxy 30 48.4 ethylated, branched MW ~ 1 million) N, N'-di (2- 29 45.4 hydroxybenzyl) ethylenediamine-N, N'-diacetic acid Trans-1, 2- acid diamino 31 48.6 cyclohexan-N, N, N ', N' -tetraacetic acid Not stabilized 31 38.0 EDTA 30 17 MW = Molecular weight Table 2 100 ° C Compound Time [h] Hydroxylamine content [%] Polyethylenimine (not 6 47.8 substituted, branched, PM-800) Polyethylenimine (amidated, 47.0 branched MW ~ 4000) Polyethylenimine (carboxyl 49.5 ethylated, branched PM-1000) Polyethylenimine 48.5 (carboxylated, branched, (MW ~ 1 million) Transidic acid 1, 2-diamino 49.9 cyclohexan-N, N, N ', N'-tetraacetic acid Not stabilized 6 EDTA 6 20 It is evident that the concentration of hydroxylamine in the non-stabilized samples fell sharply. The concentration of the samples to which the known EDTA stabilizer had been added actually dropped even more than the non-stabilized samples. On the contrary, the concentration of the stabilized samples according to the invention only decreased slightly.

Claims (9)

1. A stabilized hydroxylamine solution comprising, as a stabilizer, at least one compound of the formula I RXR2N-A-NR3R4 (I) in which A is alkylene, alkenylene, alkynylene, cycloalkylene, cycloalkenylene, arylene, or-, m- or p-xylylene, a saturated or unsaturated 5- or 6-membered heterocycle having a nitrogen atom, the radicals being capable of containing 1, 2 or 3 substituents which are independently selected from alkyl, alkoxy, and hydroxyl, or is -X- [- NR-B-] -., in which B and X are CH2CH: - or - CH2CHCH -, n is 10-50,000, R is H, alkylene, ethylene or propylene which is substituted by OH , NH, CHCOR5, or COOH, or is CSSH, CH CN or CHP? 3H-, or is a bridge to a nitrogen-nitrogen atom of another polyethylene imine or polypropylene imine chain, the bridge is formed by -X- [-NR -B-] -. or CH 2 CHOH CH 2 - [- O CH 2 CH 2 -] - P CH 2 CHOH CH 2 - wherein o and p independently are 1-15, R 5 is H, C 1 or C 0 alkyl or CHR 6 COR 6 where R 6 is C 2 C alkyl ? 8 R ^ R ^ R3, and R4 independent of each other are H CH2COOH, CH2P03H2, alkyl, acyl, CH2CH2OH, CH: CH2NH or wherein R7 is OH, SH; NH :, CN, COOH, alkyl 1 alkoxy, or the salts thereof, with the exceptions of the acid ethylene diamine tetra acetic and the N-hydroxyethylene diamino tetra acetic acid and the salts thereof.

2. The stabilized hydroxylamine solution according to claim 1, wherein the stabilizer is at least one compound of the formula I or a salt thereof in which A is alkylene, alkenylene, cycloalkylene, arylene, or -X- [-NR-B -] -, B and X are -CH; -CH2- and n, R, and R * to R1 are as defined in claim 1.

3. The stabilized hydroxylamine solution according to claim 2 , wherein the stabilizer is at least one compound of the formula I or a salt thereof in which A is alkylene, cycloalkylene or -X - [- NR-E -] - r and B, X, n and R: a R "are as defined in claim 2.

4. The stabilized hydroxylamine solution according to claim 1, wherein the stabilizer is at least one compound of the formula I or a salt thereof in which A is alkylene, cycloalkylene and R 1 to R 4 independent of each other are CH 2 COOH, CHP03H2 or wherein R7 is as defined in claim 1.

5. The stabilized hydroxylamine solution according to claim 4, wherein the stabilizer is at least one compound of the formula I or a salt thereof in which A is cyclohexylene or -CHCH2- and R1 to R independent of each other are CH2COOH or wherein R1 is OH, SH, NH2, or COOH

6. The stabilized hydroxylamine solution according to claim 5, wherein the stabilizer is acidic trans-1, 2-diaminocyclohexan-N, N, N ', N' -tetraacetic acid and / or N, N '-di (2-hydroxybenzyl) ethylenediamine-N, N'-diacetic acid. The stabilized hydroxylamine solution according to claim 1, wherein the stabilizer is at least one compound of the formula I or a salt thereof, wherein A is -X - [- NR-B -] - r;, B and X are -CH2CH: -, n is from 10 to 50,000, R is CH2COOH, CH2CH2COOH, CH2CH2OH, CH2CH2NH2, NHCOR5 or CSSH or is a bridge as defined in claim 1 to a nitrogen atom of another polyethylene imine or polypropylene imine chain, R5 is as defined in claim 1, and R1 to R4 independent of each other are H, alkyl or acyl of Ci to C19 8. A stabilized hydroxylamine solution according to any of the preceding claims, containing 0.001-20% by weight, in particular 0.001-10% by weight preferably 0.01 to 5% by weight, particularly preferably 0.02-2% by weight of the stabilizer based on hydroxylamine. 9. The use of at least one compound as defined in any of claims 1 to 7 for stabilizing hydroxylamine solutions.