PROCESS FOR RECOVERING A MIXTURE COMPRISING A (THIO)PHOSPHORIC ACID DERIVATIVE

Abstract

Provided herein is a use of a high-boiling solvent in a mixture comprising a (thio)phosphoric acid derivative and a process including the addition of a high-boiling solvent to a mixture comprising a (thio)phosphoric acid derivative to recover the (thio)phosphoric acid from the mixture by an evaporation process.

Claims

1. A method of using at least one high-boiling solvent in a mixture comprising at least one (thio)phosphoric acid derivative and at least one volatile component for preventing decomposition or solids formation of the at least one (thio)phosphoric acid derivative in an evaporation process, wherein said evaporation process comprises: separating the at least one (thio)phosphoric acid derivative from the at least one volatile component; and recovering as a bottom product in a form of a first mixture (1) comprising components: (1a) the at least one (thio)phosphoric acid derivative; and (1b) the at least one high-boiling solvent.

2. The method according to claim 1, wherein the at least one volatile component comprises at least one solvent having a boiling point of at least 30? C. lower than a boiling point of the at least one high-boiling solvent.

3. The method according to claim 1, wherein the at least one high-boiling solvent is further used as a formulation agent for the at least one (thio)phosphoric acid derivative in the recovered first mixture (1).

4. A process for recovering at least one (thio)phosphoric acid derivative from a first mixture comprising the at least one (thio)phosphoric acid derivative and at least one solvent, wherein the process comprises: adding at least one high-boiling solvent to the first mixture so as to form a second mixture (2) comprising components: (2a) at least one (thio)phosphoric acid derivative; (2b) at least one high-boiling solvent; and (2c) the at least one solvent, the at least one solvent having a boiling point that is at least 30? C. lower than a boiling point of the at least one high-boiling solvent; and and separating a third mixture (1) from said second mixture (2), wherein said third mixture (1) comprises components: (1a) the at least one (thio)phosphoric acid derivative; and (1b) the at least one high-boiling solvent; by evaporating the at least one solvent component (2c) of the second mixture (2) and collecting the third mixture (1) as a bottom product.

5. The process according to claim 4, wherein evaporating the at least one solvent component (2c) of the second mixture (2) and collecting the third mixture (1) as the bottom product is performed by: (i) continuously introducing a stream of the second mixture (2) into at least one thin film evaporator operating at a temperature of from 40? C. to 160? C. and at a pressure of from 5 mbar to 300 mbar (0.5 kPa to 30 kPa); and (ii) continuously collecting the bottom product.

6. A mixture (2) comprising: (2a) at least one (thio)phosphoric acid derivative; (2b) at least one high-boiling solvent; and (2c) at least one solvent having a boiling point that is at least 30? C. lower than the boiling point of the at least one high-boiling solvent.

7. The mixture according to claim 6, wherein the at least one (thio)phosphoric acid derivative is selected from the group consisting of: (thio)phosphoric acid triamides according to general formula (I) and (thio)phosphoric acid ester amides according to general formula (IIa) or (IIb); wherein general formula (I) is ##STR00055## wherein X.sup.1 is O or S; R.sup.1 is C.sub.1-C.sub.20-alkyl, C.sub.3-C.sub.20-cycloalkyl, C.sub.6-C.sub.20-aryl, C.sub.6-C.sub.20-aryl-C.sub.1-C.sub.4-alkyl, or C.sub.1-C.sub.6- (di)alkylaminocarbonyl; R.sup.2 is H, C.sub.1-C.sub.20-alkyl, C.sub.3-C.sub.20-cycloalkyl, C.sub.6-C.sub.20-aryl, C.sub.6-C.sub.20-aryl-C.sub.1-C.sub.4-alkyl, or C.sub.1-C.sub.6-(di)alkylaminocarbonyl; or R.sup.1 and R.sup.2 together with the nitrogen atom linking them define a 5- or 6-membered saturated or unsaturated heterocyclic radical, which optionally comprises 1 or 2 further heteroatoms selected from the group consisting of N, O, and S; and R.sup.3, R.sup.4, R.sup.5, and R.sup.6 are independently of each other selected from the group consisting of H and C.sub.1-C.sub.4-alkyl; and wherein general formula (IIa) is ##STR00056## wherein X.sup.2 is O or S; R.sup.7 is C.sub.1-C.sub.20-alkyl, C.sub.3-C.sub.20-cycloalkyl, C.sub.6-C.sub.20-aryl, C.sub.6-C.sub.20-aryl-C.sub.1-C.sub.4-alkyl, or C.sub.1-C.sub.6- (di)alkylaminocarbonyl; and R.sup.8, R.sup.9, R.sup.10, and R.sup.11 are independently of each other selected from the group consisting of H and C.sub.1-C.sub.4-alkyl; and wherein general formula (IIb) is ##STR00057## wherein X.sup.3 is O or S; R.sup.12 is C.sub.1-C.sub.20-alkyl, C.sub.3-C.sub.20-cycloalkyl, C.sub.6-C.sub.20-aryl, C.sub.6-C.sub.20-aryl-C.sub.1-C.sub.4-alkyl, or C.sub.1-C.sub.6- (di)alkylaminocarbonyl; R.sup.15 is C.sub.1-C.sub.20-alkyl, C.sub.3-C.sub.20-cycloalkyl, C.sub.6-C.sub.20-aryl, C.sub.6-C.sub.20-aryl-C.sub.1-C.sub.4-alkyl, or C.sub.1-C.sub.6- (di)alkylaminocarbonyl; and R.sup.13 and R.sup.14 are independently of each other selected from the group consisting of H and C.sub.1-C.sub.4-alkyl.

8. The mixture according to claim 6, wherein the at least one (thio)phosphoric acid derivative has a melting point of at least 40? C.

9. The mixture according to claim 6, wherein the at least one (thio)phosphoric acid derivative comprises N-(n-butyl)thiophosphoric acid triamide (NBPT), N-(n-propyl)thiophosphoric acid triamide (NPPT), or a combination thereof.

10. The mixture according to claim 6, wherein the at least one (thio)phosphoric acid derivative comprises N-(n-propyl)thiophosphoric acid triamide (NPPT).

11. The mixture according to claim 6, wherein the at least one high-boiling solvent has a boiling point of at least 130? C.

12. The mixture according to claim 6, wherein the at least one high-boiling solvent is selected from the group consisting of: (i) polyamines; (ii) alcohols; (iii) glycol ethers; (iv) glycol thioethers; (v) amino alcohols; (vi) ether amines; (vii) amines; (viii) carboxylic acid amides; (ix) carboxylic acid esters; (x) ketones; (xi) carbonate esters and ureas; and (xii) sulfoxides.

13. The mixture according to claim 6, wherein the at least one solvent has a boiling point of at most 130? C.

14. The mixture according to claim 6, wherein the at least one solvent is an ether or a carboxylic acid ester.

15. The mixture according to claim 6, wherein the mixture further comprises at least one HCl scavenger that has a boiling point of at most 180? C.

16. The mixture according to claim 15, wherein the at least one HCl scavenger is a tertiary amine.

17. The process according to claim 4, wherein the first mixture further comprises at least one HCl scavenger having a boiling point of at least 30? C. lower than the boiling point of the at least one high-boiling solvent.

18. The second mixture according to claim 6 further comprising: at least one HCl scavenger having a boiling point of at least 30? C. lower than the boiling point of the at least one high-boiling solvent.

19. The mixture according to claim 9, wherein the at least one (thio)phosphoric acid derivative comprises a combination of N-(n-butyl)thiophosphoric acid triamide (NBPT) and N-(n-propyl)thiophosphoric acid triamide (NPPT).

20. The mixture according to claim 14, wherein the at least one solvent is a cyclic ether or an acyclic carboxylic acid ester.

Description

[0722] FIG. 1 shows that the thus obtained concentrated product mixture comprising the at least one (thio)phosphoric acid derivative (component (2a)), at least one solvent (component (2c)), and optionally at least one HCl scavenger (component (2d)), is preferably mixed with at least one high-boiling solvent (component (2b)) via a continuously operated mixer, for example a static mixture, to provide mixture (2), which is then introduced into an evaporator to evaporate components (2c) and (2d) and recover mixture (1). The volatile components (2c) and (2d) may be condensed in a heat exchanger, and the condensed solvent may be recycled in the preparation process of the (thio)phosphoric acid derivative. The bottom product of the evaporator is then fed into a storage vessel, in which it can e.g. be mixed with further formulation components.

[0723] FIG. 2 shows that the thus obtained concentrated product mixture comprising the at least one (thio)phosphoric acid derivative (component (2a)), at least one solvent (component (2c)), and optionally at least one HCl scavenger (component (2d)), is preferably mixed with at least one high-boiling solvent (component (2b)) via a continuously operated mixer, for example a static mixer, to provide mixture (2), which is then introduced sequentially into two wiped film evaporators to recover mixture (1). The volatile components (2c) and (2d) may be condensed in one or two heat exchangers, and the condensed solvent may be recycled in the preparation process of the (thio)phosphoric acid derivative. The bottom product of the second wiped film evaporator is then fed into a storage vessel, in which it can e.g. be mixed with further formulation components.

[0724] As can be derived from FIGS. 1 and 2, according to one embodiment, the process of the invention comprises a step of adding the at least one high-boiling solvent (component (2d)) to a concentrated mixture comprising the at least one (thio)phosphoric acid derivative (component (2a)), at least one solvent (component (2c)), and optionally at least one HCl scavenger (component (2d)) to provide mixture (2) as defined herein. It is to be understood that this step is performed before the evaporation of components (2c) and (2d) to recover mixture (1).

[0725] However, in alternative embodiments as indicated above, the at least one high-boiling solvent may already be added to the reaction mixture when preparing the at least one (thio)phosphoric acid derivative (component (2a)), so that the concentrated reaction mixture comprising the at least one (thio)phosphoric acid derivative (component (2a)), at least one solvent (component (2c)), and optionally at least one HCl scavenger (component (2d)) already contains the at least one high-boiling solvent (component (2b)). It is emphasized that the at least one high-boiling solvent may be added either in the first or in the second reaction step of the preparation of the at least one (thio)phosphoric acid derivative as defined above.

[0726] The present invention also relates to a mixture (2) as defined herein, which comprises as components [0727] (2a) a product comprising at least one (thio)phosphoric acid derivative, which is selected from [0728] (i) [0729] (thio)phosphoric acid triamides according to general formula (I)

##STR00040## [0730] wherein [0731] X.sup.1 is O or S; [0732] R.sup.1 is C.sub.1-C.sub.20-alkyl, C.sub.3-C.sub.20-cycloalkyl, C.sub.6-C.sub.20-aryl, C.sub.6-C.sub.20-aryl-C.sub.1-C.sub.4-alkyl, or C.sub.1-C.sub.6-(di)alkylaminocarbonyl; [0733] R.sup.2 is H, C.sub.1-C.sub.20-alkyl, C.sub.3-C.sub.20-cycloalkyl, C.sub.6-C.sub.20-aryl, C.sub.6-C.sub.20-aryl-C.sub.1-C.sub.4-alkyl, or C.sub.1-C.sub.6-(di)alkylaminocarbonyl; or [0734] R.sup.1 and R.sup.2 together with the nitrogen atom linking them define a 5- or 6-membered saturated or unsaturated heterocyclic radical, which optionally comprises 1 or 2 further heteroatoms selected from the group consisting of N, O, and S; and [0735] R.sup.3, R.sup.4, R.sup.5, and R.sup.6 are independently of each other selected from the group consisting of H and C.sub.1-C.sub.4-alkyl; [0736] and [0737] (ii) [0738] (thio)phosphoric acid ester amides according to any one of general formula (IIa)

##STR00041## [0739] wherein [0740] X.sup.2 is O or S; [0741] R.sup.7 is C.sub.1-C.sub.20-alkyl, C.sub.3-C.sub.20-cycloalkyl, C.sub.6-C.sub.20-aryl, C.sub.6-C.sub.20-aryl-C.sub.1-C.sub.4-alkyl, or C.sub.1-C.sub.6-(di)alkylaminocarbonyl; and [0742] R.sup.8, R.sup.9, R.sup.10, and R.sup.11 are independently of each other selected from the group consisting of H and C.sub.1-C.sub.4-alkyl; [0743] or general formula (IIb)

##STR00042## [0744] wherein [0745] X.sup.3 is O or S; [0746] R.sup.12 is C.sub.1-C.sub.20-alkyl, C.sub.3-C.sub.20-cycloalkyl, C.sub.6-C.sub.20-aryl, C.sub.6-C.sub.20-aryl-C.sub.1-C.sub.4-alkyl, or C.sub.1-C.sub.6-(di)alkylaminocarbonyl; [0747] R.sup.15 is C.sub.1-C.sub.20-alkyl, C.sub.3-C.sub.20-cycloalkyl, C.sub.6-C.sub.20-aryl, C.sub.6-C.sub.20-aryl-C.sub.1-C.sub.4-alkyl, or C.sub.1-C.sub.6-(di)alkylaminocarbonyl; and [0748] R.sup.13 and R.sup.14 are independently of each other selected from the group consisting of H and C.sub.1-C.sub.4-alkyl; [0749] (2b) at least one high-boiling solvent; [0750] (2c) at least one solvent having a boiling point, which is at least 30? C. lower than the boiling point of the at least one high-boiling solvent of component (2b); and [0751] (2d) optionally at least one HCl scavenger having a boiling point, which is at least 30? C. lower than the boiling point of the at least one high-boiling solvent of component (2b).

[0752] Preferences with regard to the individual components of mixture (2) have already been provided above.

[0753] In summary, the present invention relates to the following embodiments.

[0754] 1. A process for separating or recovering

[0755] a mixture (1) comprising as components [0756] (1a) a product comprising at least one (thio)phosphoric acid derivative, which is selected from [0757] (i) [0758] (thio)phosphoric acid triamides according to general formula (I)

##STR00043## [0759] wherein [0760] X.sup.1 is O or S; [0761] R.sup.1 is C.sub.1-C.sub.20-alkyl, C.sub.3-C.sub.20-cycloalkyl, C.sub.6-C.sub.20-aryl, C.sub.6-C.sub.20-aryl-C.sub.1-C.sub.4-alkyl, or C.sub.1-C.sub.6-(di)alkylaminocarbonyl; [0762] R.sup.2 is H, C.sub.1-C.sub.20-alkyl, C.sub.3-C.sub.20-cycloalkyl, C.sub.6-C.sub.20-aryl, C.sub.6-C.sub.2O-aryl-C.sub.1-C.sub.4-alkyl, or C.sub.1-C.sub.6-(di)alkylaminocarbonyl; or [0763] R.sup.1 and R.sup.2 together with the nitrogen atom linking them define a 5- or 6-membered saturated or unsaturated heterocyclic radical, which optionally comprises 1 or 2 further heteroatoms selected from the group consisting of N, O, and S; and [0764] R.sup.3, R.sup.4, R.sup.5, and R.sup.6 are independently of each other selected from the group consisting of H and C.sub.1-C.sub.4-alkyl; [0765] and [0766] (ii) [0767] (thio)phosphoric acid ester amides according to any one of general formula (IIa)

##STR00044## [0768] wherein [0769] X.sup.2 is O or S; [0770] R.sup.7 is C.sub.1-C.sub.20-alkyl, C.sub.3-C.sub.20-cycloalkyl, C.sub.6-C.sub.20-aryl, C.sub.6-C.sub.20-aryl-C.sub.1-C.sub.4-alkyl, or C.sub.1-C.sub.6-(di)alkylaminocarbonyl; and [0771] R.sup.8, R.sup.9, R.sup.10, and R.sup.11 are independently of each other selected from the group consisting of H and C.sub.1-C.sub.4-alkyl; [0772] or general formula (IIb)

##STR00045## [0773] wherein [0774] X.sup.3 is O or S; [0775] R.sup.12 is C.sub.1-C.sub.20-alkyl, C.sub.3-C.sub.20-cycloalkyl, C.sub.6-C.sub.20-aryl, C.sub.6-C.sub.20-aryl-C.sub.1-C.sub.4-alkyl, or C.sub.1-C.sub.6-(di)alkylaminocarbonyl; [0776] R.sup.15 is C.sub.1-C.sub.20-alkyl, C.sub.3-C.sub.20-cycloalkyl, C.sub.6-C.sub.20-aryl, C.sub.6-C.sub.20-aryl-C.sub.1-C.sub.4-alkyl, or C.sub.1-C.sub.6-(di)alkylaminocarbonyl; and [0777] R.sup.13 and R.sup.14 are independently of each other selected from the group consisting of H and C.sub.1-C.sub.4-alkyl; [0778] and [0779] (1b) at least one high-boiling solvent;

[0780] from a mixture (2) comprising as components [0781] (2a) component (1a) of mixture (1); [0782] (2b) component (1b) of mixture (1); [0783] (2c) at least one solvent having a boiling point, which is at least 30? C. lower than the boiling point of the at least one high-boiling solvent of component (1b) of mixture (1); and [0784] (2d) optionally at least one HCl scavenger having a boiling point, which is at least 30? C. lower than the boiling point of the at least one high-boiling solvent of component (1b) of mixture (1);

[0785] wherein the process comprises evaporating components (2c) and (2d) of mixture (2) and collecting mixture (1) as the bottom product.

[0786] 2. The process of embodiment 1, wherein component (1a) of mixture (1) comprises at least one (thio)phosphoric acid derivative, which is selected from [0787] (i) [0788] (thio)phosphoric acid triamides according to general formula (I)

##STR00046## [0789] wherein [0790] X.sup.1 is O or S; [0791] R.sup.1 is C.sub.1-C.sub.8-alkyl, C.sub.5-C.sub.6-cycloalkyl, phenyl, or benzyl; [0792] R.sup.2 is H, or C.sub.1-C.sub.4-alkyl; and [0793] R.sup.3, R.sup.4, R.sup.5, and R.sup.6 are each H; [0794] and [0795] (ii) [0796] (thio)phosphoric acid ester amides according to any one of general formula (IIa)

##STR00047## [0797] wherein [0798] X.sup.2 is O or S; [0799] R.sup.7 is C.sub.1-C.sub.8-alkyl, C.sub.5-C.sub.6-cycloalkyl, phenyl, or benzyl; and [0800] R.sup.8, R.sup.9, R.sup.10, and R.sup.11 are each H; [0801] or general formula (IIb)

##STR00048## [0802] wherein [0803] X.sup.3 is O or S; [0804] R.sup.12 is C.sub.1-C.sub.8-alkyl, C.sub.5-C.sub.6-cycloalkyl, phenyl, or benzyl; [0805] R.sup.15 is C.sub.1-C.sub.8-alkyl, C.sub.5-C.sub.6-cycloalkyl, phenyl, or benzyl; and [0806] R.sup.13 and R.sup.14 are each H.

[0807] 3. The process of embodiment 1 or 2, wherein component (1a) of mixture (1) comprises at least one (thio)phosphoric acid derivative, which has a melting point of at least 40? C., preferably at least 50? C.

[0808] 4. The process of any one of embodiments 1 to 3, wherein component (1a) of mixture (1) comprises at least one (thio)phosphoric acid derivative, which is selected from the group consisting of [0809] N-benzyl-N-methylthiophosphoric acid triamide, N,N-diethylthiophosphoric acid triamide, N-(n-butyl)thiophosphoric acid triamide, N-isopropylphosphoric acid triamide, N-(n-hexyl)thiophosphoric acid triamide, N-(sec-butyl)thiophosphoric acid triamide, N,N-diethylphosphoric acid triamide, N-(n-propyl)thiophosphoric acid triamide, N,N-diisopropylthiophosphoric acid triamide, N,N-dimethylthiophosphoric acid triamide, N-(n-octyl)phosphoric acid triamide, N-(n-butyl)phosphoric acid triamide, N-cyclohexylphosphoric acid triamide, N-benzyl-N-methylphosphoric acid triamide, N,N-dimethylphosphoric acid triamide, N-cyclohexylthiophosphoric acid triamide; [0810] O-ethylphosphoric acid ester diamide, O-phenylthiophosphoric acid ester diamide, O,O-diphenylphosphoric acid diester amide, and O-phenylphosphoric acid ester diamide;

[0811] and which is preferably selected from the group consisting of [0812] N,N-diethylthiophosphoric acid triamide, N-(n-butyl)thiophosphoric acid triamide, N-isopropylphosphoric acid triamide, N-(n-hexyl)thiophosphoric acid triamide, N-(sec-butyl)thiophosphoric acid triamide, N,N-diethylphosphoric acid triamide, N-(n-propyl)thiophosphoric acid triamide, N,N-diisopropylthiophosphoric acid triamide, N,N-dimethylthiophosphoric acid triamide, N-(n-octyl)phosphoric acid triamide, N-(n-butyl)phosphoric acid triamide, N-cyclohexylphosphoric acid triamide, N-benzyl-N-methylphosphoric acid triamide, N,N-dimethylphosphoric acid triamide, N-cyclohexylthiophosphoric acid triamide; [0813] O-ethylphosphoric acid ester diamide, O-phenylthiophosphoric acid ester diamide, O,O-diphenylphosphoric acid diester amide, and O-phenylphosphoric acid ester diamide.

[0814] 5. The process of any one of embodiments 1 to 4, wherein component (1a) of mixture (1) comprises N-(n-butyl)thiophosphoric acid triamide, N-(n-propyl)thiophosphoric acid triamide, or the combination thereof, preferably the combination of N-(n-butyl)thiophosphoric acid triamide and N-(n-propyl)thiophosphoric acid triamide.

[0815] 6. The process of any one of embodiments 1 to 5, wherein component (1a) of mixture (1) comprises at least one (thio)phosphoric acid derivative, which has a melting point of at least 60? C., preferably at least 80? C., more preferably at least 85? C.

[0816] 7. The process of any one of embodiments 1 to 4 or 6, wherein component (1a) of mixture (1) comprises at least one (thio)phosphoric acid derivative, which is selected from the group consisting of [0817] N-isopropylphosphoric acid triamide, N-(n-hexyl)thiophosphoric acid triamide, N-(sec-butyl)thiophosphoric acid triamide, N,N-diethylphosphoric acid triamide, N-(n-propyl)thiophosphoric acid triamide, N,N-diisopropylthiophosphoric acid triamide, N,N-dimethylthiophosphoric acid triamide, N-(n-octyl)phosphoric acid triamide, N-(n-butyl)phosphoric acid triamide, N-cyclohexylphosphoric acid triamide, N-benzyl-N-methylphosphoric acid triamide, N,N-dimethylphosphoric acid triamide, N-cyclohexylthiophosphoric acid triamide; [0818] O-ethylphosphoric acid ester diamide, O-phenylthiophosphoric acid ester diamide, O,O-diphenylphosphoric acid diester amide, and O-phenylphosphoric acid ester diamide;

[0819] and which is preferably selected from the group consisting of [0820] N-(n-propyl)thiophosphoric acid triamide, N,N-diisopropylthiophosphoric acid triamide, N,N-dimethylthiophosphoric acid triamide, N-(n-octyl)phosphoric acid triamide, N-(n-butyl)phosphoric acid triamide, N-cyclohexylphosphoric acid triamide, N-benzyl-N-methylphosphoric acid triamide, N,N-dimethylphosphoric acid triamide, N-cyclohexylthiophosphoric acid triamide; [0821] O-ethylphosphoric acid ester diamide, O-phenylthiophosphoric acid ester diamide, O,O-diphenylphosphoric acid diester amide, and O-phenylphosphoric acid ester diamide.

[0822] 8. The process of any one of embodiments 1 to 7, wherein component (1a) of mixture (1) comprises N-(n-propyl)thiophosphoric acid triamide, and wherein mixture (1) preferably does not comprise N-(n-butyl)thiophosphoric acid triamide.

[0823] 9. The process of any one of embodiments 1 to 8, wherein the at least one high-boiling solvent of component (1b) of mixture (1) has a boiling point of at least 130? C., preferably at least 160? C., more preferably at least 190? C., most preferably at least 220? C., particularly preferably at least 250? C.

[0824] 10. The process of any one of embodiments 1 to 9, wherein the at least one high-boiling solvent of component (1b) of mixture (1) is a polar protic or a polar aprotic high-boiling solvent.

[0825] 11. The process of any one of embodiments 1 to 10, wherein the at least one high-boiling solvent of component (1b) of mixture (1) is selected from the group consisting of [0826] (i) polyamines; [0827] (ii) alcohols; [0828] (iii) glycol ethers; [0829] (iv) glycol thioethers; [0830] (v) amino alcohols; [0831] (vi) ether amines; [0832] (vii) amines; [0833] (viii) carboxylic acid amides; [0834] (ix) carboxylic acid esters; [0835] (x) ketones; [0836] (xi) carbonate esters and ureas; and [0837] (xii) sulfoxides.

[0838] 12. The process of any one of embodiments 1 to 11, wherein the at least one high-boiling solvent of component (1b) of mixture (1) is selected from the group consisting of polyethylene imine, C.sub.5-C.sub.20-alkyl acetates, propylene glycol, diethylene glycol, glycerin, triethyleneglycol-n-butylether, thiodiglycol, diethanolisopropanolamine, N,N,N-trimethylaminoethylethanolamine, N,N,N,N-tetrakis(2-hydroxypropyl)ethylenediamine, dimorpholinodiethylether, bis(2-dimethylaminoethyl)ether, N-acetyl morpholine, N,N,N,N-tetramethyl-1,6-hexanediamine, N,N,N,N-tetramethyl-1,3-propanediamine, N,N,N-tris(dimethylaminopropyl)hexahydrotriazine, triethylendiamine (DABCO), N,N-dimethylbutyramide, N-formyl pyrrolidone, N-methyl pyrrolidone, dimethyl-2-methylpentandioate, 2-ethylhexyl lactate, dimethylsulfoxide, benzyl alcohol, cyclohexanone, propylene carbonate, N,N-dimethyl octanamide, N,N-dimethyl decanamide, 2-ethylhexanol, N,N-dimethylethylene urea, methyl oleate, tocopherol acetate, N,N-dimethyllauric amide, N,N-dimethylmyristic amide, N-[2-(acetyloxy)ethyl]-N-methyl acetamide, methyl caprylate, methyl laurate, methyl palmitate, capric/caprylic triglyceride, N,N-dimethyl lactamide, triethanolamine, 1,1,1,1-ethylenedinitrilotetrapropan-2-ol, N,N,N,N,N,N-hexamethyl-1,3,5-triazin-1,3,5(2H,4H,6H)-tripropanamin, 2-propylheptan-1-ol, n-acetylmorpholine, n-formylmorpholine, dimethyl succinate, di(2-ethylhexyl) adipate, and diethyl phthalate.

[0839] 13. The process of any one of embodiments 1 to 12, wherein the at least one high-boiling solvent of component (1b) of mixture (1) is [0840] an amino alcohol, preferably diethanolisopropanolamine or triethanolamine; or [0841] propylene glycol; or [0842] dimethylsulfoxide;

[0843] and wherein preferably the at least one high-boiling solvent of component (1b) of mixture (1) is triethanolamine.

[0844] 14. The process of any one of embodiments 1 to 12, wherein the at least one high-boiling solvent of component (1b) of mixture (1) is a polyalkyleneimine, preferably polyethyleneimine.

[0845] 15. The process of any one of embodiments 1 to 12, wherein the at least one high-boiling solvent of component (1b) of mixture (1) is a C.sub.5-C.sub.20-alkylacetate, preferably a C.sub.6-C.sub.20-alkylacetate, more preferably a C.sub.7-C.sub.20-alkylacetate.

[0846] 16. The process of any one of embodiments 1 to 12, wherein the at least one high-boiling solvent of component (1b) of mixture (1) is a solvent, which does not comprise a hydroxyl or primary amino group, and is preferably a tertiary amine or an ether amine or a tertiary lactam.

[0847] 17. The process of any one of the embodiments 1 to 16, wherein components (1a) and (1b) of mixture (1) are together present in an amount of at least 75 wt.-%, preferably at least 85 wt. %, more preferably at least 90 wt.-%, most preferably at least 95 wt.-%, based on the total weight of mixture (1).

[0848] 18. The process of any one of embodiments 1 to 17, wherein components (1a) and (1b) of mixture (1) are present in a weight ratio of from 90:10 to 10:90, preferably 90:10 to 30:70, more preferably 80:20 to 40:60, most preferably from 70:30 to 40:60.

[0849] 19. The process of any one of embodiments 1 to 18, wherein the at least one solvent of component (2c) of mixture (2) has a boiling point of at most 130? C., preferably at most 100? C., more preferably at most 85? C.

[0850] 20. The process of any one of embodiments 1 to 19, wherein the at least one solvent of component (2c) of mixture (2) has a boiling point, which is at least 40? C., preferably at least 50? C., more preferably at least 60? C., most preferably at least 80? C., lower than the boiling point of the at least one high-boiling solvent of component (1b) of mixture (1).

[0851] 21. The process of any one of embodiments 1 to 20, wherein the at least one solvent of component (2c) of mixture (2) is an aprotic solvent, preferably a polar aprotic solvent.

[0852] 22. The process of any one of embodiments 1 to 21, wherein the at least one solvent of component (2c) of mixture (2) is an ether or a carboxylic acid ester, preferably a cyclic ether or an acyclic carboxylic acid ester, more preferably tetrahydrofuran, 2-methyltetrahydrofuran, or ethyl acetate.

[0853] 23. The process of any one of embodiments 1 to 22, wherein the at least one HCl scavenger of component (2d) of mixture (2) has a boiling point of at most 180? C., preferably at most 160? C.

[0854] 24. The process of any one of embodiments 1 to 23, wherein the at least one HCl scavenger of component (2d) of mixture (2) has a boiling point, which is at least 40? C., preferably at least 50? C., more preferably at least 60? C., most preferably at least 80? C., lower than the boiling point of the at least one high-boiling solvent of component (1b) of mixture (1).

[0855] 25. The process of any one of embodiments 1 to 24, wherein the at least one HCl scavenger of component (2d) of mixture (2) is a tertiary amine, preferably triethylamine or tri-n-propylamine, more preferably tri-n-propylamine.

[0856] 26. The process of any one of embodiments 1 to 25, wherein components (2a), (2b), (2c), and (2d) of mixture (2) are together present in an amount of at least 95 wt.-%, preferably at least 97 wt.-%, more preferably at least 98 wt.-%, most preferably at least 99 wt.-%, based on the total weight of mixture (2).

[0857] 27. The process of any one of the embodiments 1 to 26, wherein the process comprising evaporating components (2c) and (2d) of mixture (2) and collecting mixture (1) as the bottom product is performed by:

[0858] (i) continuously introducing a stream of the mixture (2) into at least one thin film evaporator operating at a temperature of from 40? C. to 160? C. and at a pressure of from 5 mbar to 300 mbar (0.5 kPa to 30 kPa), and

[0859] (ii) continuously collecting the bottom product.

[0860] 28. The process of embodiment 27, wherein the at least one thin film evaporator is operated at a temperature in the range of from 50? C. to 110? C. and at a pressure of from 5 mbar to 250 mbar (2 kPa to 10 kPa).

[0861] 29. A mixture (2), which comprises as components [0862] (2a) a product comprising at least one (thio)phosphoric acid derivative, which is selected from [0863] (i) [0864] (thio)phosphoric acid triamides according to general formula (I)

##STR00049## [0865] wherein [0866] X.sup.1 is O or S; [0867] R.sup.1 is C.sub.1-C.sub.20-alkyl, C.sub.3-C.sub.20-cycloalkyl, C.sub.6-C.sub.20-aryl, C.sub.6-C.sub.20-aryl-C.sub.1-C.sub.4-alkyl, or C.sub.1-C.sub.6-(di)alkylaminocarbonyl; [0868] R.sup.2 is H, C.sub.1-C.sub.20-alkyl, C.sub.3-C.sub.20-cycloalkyl, C.sub.6-C.sub.20-aryl, C.sub.6-C.sub.20-aryl-C.sub.1-C.sub.4-alkyl, or C.sub.1-C.sub.6-(di)alkylaminocarbonyl; or [0869] R.sup.1 and R.sup.2 together with the nitrogen atom linking them define a 5- or 6-membered saturated or unsaturated heterocyclic radical, which optionally comprises 1 or 2 further heteroatoms selected from the group consisting of N, O, and S; and [0870] R.sup.3, R.sup.4, R.sup.5, and R.sup.6 are independently of each other selected from the group consisting of H and C.sub.1-C.sub.4-alkyl; [0871] and [0872] (ii) [0873] (thio)phosphoric acid ester amides according to any one of general formula (IIa)

##STR00050## [0874] wherein [0875] X.sup.2 is O or S; [0876] R.sup.7 is C.sub.1-C.sub.20-alkyl, C.sub.3-C.sub.20-cycloalkyl, C.sub.6-C.sub.20-aryl, C.sub.6-C.sub.20-aryl-C.sub.1-C.sub.4-alkyl, or C.sub.1-C.sub.6-(di)alkylaminocarbonyl; and [0877] R.sup.8, R.sup.9, R.sup.10, and R.sup.11 are independently of each other selected from the group consisting of H and C.sub.1-C.sub.4-alkyl; [0878] or general formula (IIb)

##STR00051## [0879] wherein [0880] X.sup.3 is O or S; [0881] R.sup.12 is C.sub.1-C.sub.20-alkyl, C.sub.3-C.sub.20-cycloalkyl, C.sub.6-C.sub.20-aryl, C.sub.6-C.sub.20-aryl-C.sub.1-C.sub.4-alkyl, or C.sub.1-C.sub.6-(di)alkylaminocarbonyl; [0882] R.sup.15 is C.sub.1-C.sub.20-alkyl, C.sub.3-C.sub.20-cycloalkyl, C.sub.6-C.sub.20-aryl, C.sub.6-C.sub.20-aryl-C.sub.1-C.sub.4-alkyl, or C.sub.1-C.sub.6-(di)alkylaminocarbonyl; and [0883] R.sup.13 and R.sup.14 are independently of each other selected from the group consisting of H and C.sub.1-C.sub.4-alkyl; [0884] (2b) at least one high-boiling solvent; [0885] (2c) at least one solvent having a boiling point, which is at least 30? C. lower than the boiling point of the at least one high-boiling solvent of component (2b); and [0886] (2d) optionally at least one HCl scavenger having a boiling point, which is at least 30? C. lower than the boiling point of the at least one high-boiling solvent of component (2b).

[0887] 30. The mixture of embodiment 29, wherein component (2a) comprises at least one (thio)phosphoric acid derivative, which is selected from [0888] (i) [0889] (thio)phosphoric acid triamides according to general formula (I)

##STR00052## [0890] wherein [0891] X.sup.1 is O or S; [0892] R.sup.1 is C.sub.1-C.sub.8-alkyl, C.sub.5-C.sub.6-cycloalkyl, phenyl, or benzyl; [0893] R.sup.2 is H, or C.sub.1-C.sub.4-alkyl; and [0894] R.sup.3, R.sup.4, R.sup.5, and R.sup.6 are each H; [0895] and [0896] (ii) [0897] (thio)phosphoric acid ester amides according to any one of general formula (IIa)

##STR00053## [0898] wherein [0899] X.sup.2 is O or S; [0900] R.sup.7 is C.sub.1-C.sub.8-alkyl, C.sub.5-C.sub.6-cycloalkyl, phenyl, or benzyl; and [0901] R.sup.8, R.sup.9, R.sup.10, and R.sup.11 are each H; [0902] or general formula (IIb)

##STR00054## [0903] wherein [0904] X.sup.3 is O or S; [0905] R.sup.12 is C.sub.1-C.sub.8-alkyl, C.sub.5-C.sub.6-cycloalkyl, phenyl, or benzyl; [0906] R.sup.15 is C.sub.1-C.sub.8-alkyl, C.sub.5-C.sub.6-cycloalkyl, phenyl, or benzyl; and [0907] R.sup.13 and R.sup.14 are each H.

[0908] 31. The mixture of embodiment 29 or 30, wherein component (2a) comprises at least one (thio)phosphoric acid derivative, which has a melting point of at least 40? C., preferably at least 50? C.

[0909] 32. The mixture of any one of embodiments 29 to 31, wherein component (2a) comprises at least one (thio)phosphoric acid derivative, which is selected from the group consisting of [0910] N-benzyl-N-methylthiophosphoric acid triamide, N,N-diethylthiophosphoric acid triamide, N-(n-butyl)thiophosphoric acid triamide, N-isopropylphosphoric acid triamide, N-(n-hexyl)thiophosphoric acid triamide, N-(sec-butyl)thiophosphoric acid triamide, N,N-diethylphosphoric acid triamide, N-(n-propyl)thiophosphoric acid triamide, N,N-diisopropylthiophosphoric acid triamide, N,N-dimethylthiophosphoric acid triamide, N-(n-octyl)phosphoric acid triamide, N-(n-butyl)phosphoric acid triamide, N-cyclohexylphosphoric acid triamide, N-benzyl-N-methylphosphoric acid triamide, N,N-dimethylphosphoric acid triamide, N-cyclohexylthiophosphoric acid triamide; [0911] O-ethylphosphoric acid ester diamide, O-phenylthiophosphoric acid ester diamide, O,O-diphenylphosphoric acid diester amide, and O-phenylphosphoric acid ester diamide;

[0912] and which is preferably selected from the group consisting of [0913] N,N-diethylthiophosphoric acid triamide, N-(n-butyl)thiophosphoric acid triamide, N-isopropylphosphoric acid triamide, N-(n-hexyl)thiophosphoric acid triamide, N-(sec-butyl)thiophosphoric acid triamide, N,N-diethylphosphoric acid triamide, N-(n-propyl)thiophosphoric acid triamide, N,N-diisopropylthiophosphoric acid triamide, N,N-dimethylthiophosphoric acid triamide, N-(n-octyl)phosphoric acid triamide, N-(n-butyl)phosphoric acid triamide, N-cyclohexylphosphoric acid triamide, N-benzyl-N-methylphosphoric acid triamide, N,N-dimethylphosphoric acid triamide, N-cyclohexylthiophosphoric acid triamide; [0914] O-ethylphosphoric acid ester diamide, O-phenylthiophosphoric acid ester diamide, O,O-diphenylphosphoric acid diester amide, and O-phenylphosphoric acid ester diamide.

[0915] 33. The mixture of any one of embodiments 29 to 32, wherein component (2a) comprises N-(n-butyl)thiophosphoric acid triamide, N-(n-propyl)thiophosphoric acid triamide, or the combination thereof, preferably the combination of N-(n-butyl)thiophosphoric acid triamide and N-(n-propyl)thiophosphoric acid triamide.

[0916] 34. The mixture of any one of embodiments 29 to 33, wherein component (2a) comprises at least one (thio)phosphoric acid derivative, which has a melting point of at least 60? C., preferably at least 80? C., more preferably at least 85? C.

[0917] 35. The mixture of any one of embodiments 29 to 32 or 34, wherein component (2a) of mixture (1) comprises at least one (thio)phosphoric acid derivative, which is selected from the group consisting of [0918] N-isopropylphosphoric acid triamide, N-(n-hexyl)thiophosphoric acid triamide, N-(sec-butyl)thiophosphoric acid triamide, N,N-diethylphosphoric acid triamide, N-(n-propyl)thiophosphoric acid triamide, N,N-diisopropylthiophosphoric acid triamide, N,N-dimethylthiophosphoric acid triamide, N-(n-octyl)phosphoric acid triamide, N-(n-butyl)phosphoric acid triamide, N-cyclohexylphosphoric acid triamide, N-benzyl-N-methylphosphoric acid triamide, N,N-dimethylphosphoric acid triamide, N-cyclohexylthiophosphoric acid triamide; [0919] O-ethylphosphoric acid ester diamide, O-phenylthiophosphoric acid ester diamide, O,O-diphenylphosphoric acid diester amide, and O-phenylphosphoric acid ester diamide;

[0920] and which is preferably selected from the group consisting of [0921] N-(n-propyl)thiophosphoric acid triamide, N,N-diisopropylthiophosphoric acid triamide, N,N-dimethylthiophosphoric acid triamide, N-(n-octyl)phosphoric acid triamide, N-(n-butyl)phosphoric acid triamide, N-cyclohexylphosphoric acid triamide, N-benzyl-N-methylphosphoric acid triamide, N,N-dimethylphosphoric acid triamide, N-cyclohexylthiophosphoric acid triamide; [0922] O-ethylphosphoric acid ester diamide, O-phenylthiophosphoric acid ester diamide, O,O-diphenylphosphoric acid diester amide, and O-phenylphosphoric acid ester diamide.

[0923] 36. The mixture of any one of embodiments 29 to 35, wherein component (2a) comprises N-(n-propyl)thiophosphoric acid triamide, and wherein mixture (2) preferably does not comprise N-(n-butyl)thiophosphoric acid triamide.

[0924] 37. The mixture of any one of embodiments 29 to 36, wherein the at least one high-boiling solvent of component (2b) has a boiling point of at least 130? C., preferably at least 160? C., more preferably at least 190? C., most preferably at least 220? C., particularly preferably at least 250? C.

[0925] 38. The mixture of any one of embodiments 29 to 37, wherein the at least one high-boiling solvent of component (2b) is a polar protic or a polar aprotic high-boiling solvent.

[0926] 39. The mixture of any one of embodiments 29 to 38, wherein the at least one high-boiling solvent of component (2b) is selected from the group consisting of [0927] (i) polyamines; [0928] (ii) alcohols; [0929] (iii) glycol ethers; [0930] (iv) glycol thioethers; [0931] (v) amino alcohols; [0932] (vi) ether amines; [0933] (vii) amines; [0934] (viii) carboxylic acid amides; [0935] (ix) carboxylic acid esters; [0936] (x) ketones; [0937] (xi) carbonate esters and ureas; and [0938] (xii) sulfoxides.

[0939] 40. The mixture of any one of embodiments 29 to 39, wherein the at least one high-boiling solvent of component (2b) is selected from the group consisting of polyethylene imine, C.sub.5-C.sub.20-alkyl acetates, propylene glycol, diethylene glycol, glycerin, triethyleneglycol-n-butylether, thiodiglycol, diethanolisopropanolamine, N,N,N-trimethylaminoethylethanolamine, N,N,N,N-tetrakis(2-hydroxypropyl)ethylenediamine, dimorpholinodiethylether, bis(2-dimethyl-aminoethyl)ether, N-acetyl morpholine, N,N,N,N-tetramethyl-1,6-hexanediamine, N,N,N,N-tetramethyl-1,3-propanediamine, N,N,N-tris(dimethylaminopropyl)hexahydrotriazine, triethylendiamine (DABCO), N,N-dimethylbutyramide, N-formyl pyrrolidone, N-methyl pyrrolidone, dimethyl-2-methylpentandioate, 2-ethylhexyl lactate, dimethylsulfoxide, benzyl alcohol, cyclohexanone, propylene carbonate, N,N-dimethyl octanamide, N,N-dimethyl decanamide, 2-ethylhexanol, N,N-dimethylethylene urea, methyl oleate, tocopherol acetate, N,N-dimethyllauric amide, N,N-dimethylmyristic amide, N-[2-(acetyloxy)ethyl]-N-methyl acetamide, methyl caprylate, methyl laurate, methyl palmitate, capric/caprylic triglyceride, N,N-dimethyl lactamide, triethanolamine, 1,1,1,1-ethylenedinitrilotetrapropan-2-ol, N,N,N,N,N,N-hexamethyl-1,3,5-triazin-1,3,5(2H,4H,6H)tripropanamin, 2-propylheptan-1-ol, n-acetylmorpholine, n-formylmorpholine, dimethyl succinate, di(2-ethylhexyl) adipate, and diethyl phthalate.

[0940] 41. The mixture of any one of embodiments 29 to 40, wherein the at least one high-boiling solvent of component (2b) is [0941] an amino alcohol, preferably diethanolisopropanolamine or triethanolamine; or [0942] propylene glycol; or [0943] dimethylsulfoxide;

[0944] and wherein preferably the at least one high-boiling solvent of component (1b) of mixture (1) is triethanolamine.

[0945] 42. The mixture of any one of embodiments 29 to 40, wherein the at least one high-boiling solvent of component (2b) is a polyalkyleneimine, preferably polyethyleneimine.

[0946] 43. The mixture of any one of embodiments 29 to 40, wherein the at least one high-boiling solvent of component (2b) is a C.sub.5-C.sub.20-alkylacetate, preferably a C.sub.6-C.sub.20-alkylacetate, more preferably a C.sub.7-C.sub.20-alkylacetate.

[0947] 44. The mixture of any one of embodiments 29 to 40, wherein the at least one high-boiling solvent of component (2b) is a solvent, which does not comprise a hydroxyl or primary amino group, and is preferably a tertiary amine or an ether amine or a tertiary lactam.

[0948] 45. The mixture of any one of embodiments 29 to 44, wherein components (2a) and (2b) of mixture (2) are present in a weight ratio of from 90:10 to 10:90, preferably 90:10 to 30:70, more preferably 80:20 to 40:60, most preferably from 70:30 to 40:60.

[0949] 46. The mixture of any one of embodiments 29 to 45, wherein the at least one solvent of component (2c) has a boiling point of at most 130? C., preferably at most 100? C., more preferably at most 85? C.

[0950] 47. The mixture of any one of embodiments 29 to 46, wherein the at least one solvent of component (2c) has a boiling point, which is at least 40? C., preferably at least 50? C., more preferably at least 60? C., most preferably at least 80? C., lower than the boiling point of the at least one high-boiling solvent of component (2b).

[0951] 48. The mixture of any one of embodiments 29 to 47, wherein the at least one solvent of component (2c) is an aprotic solvent, preferably a polar aprotic solvent.

[0952] 49. The mixture of any one of embodiments 29 to 48, wherein the at least one solvent of component (2c) is an ether or a carboxylic acid ester, preferably a cyclic ether or an acyclic carboxylic acid ester, more preferably tetrahydrofuran, 2-methyltetrahydrofuran, or ethyl acetate.

[0953] 50. The mixture of any one of embodiments 29 to 49, wherein the at least one HCl scavenger of component (2d) has a boiling point of at most 180? C., preferably at most 160? C.

[0954] 51. The mixture of any one of embodiments 29 to 50, wherein the at least one HCl scavenger of component (2d) has a boiling point, which is at least 40? C., preferably at least 50? C., more preferably at least 60? C., most preferably at least 80? C., lower than the boiling point of the at least one high-boiling solvent of component (1b) of mixture (1).

[0955] 52. The mixture of any one of embodiments 29 to 51, wherein the at least one HCl scavenger of component (2d) is a tertiary amine, preferably triethylamine or tri-n-propylamine, more preferably tri-n-propylamine.

[0956] 53. The mixture of any one of embodiments 29 to 52, wherein components (2a), (2b), (2c), and (2d) of mixture (2) are together present in an amount of at least 95 wt.-%, preferably at least 97 wt.-%, more preferably at least 98 wt.-%, most preferably at least 99 wt.-%, based on the total weight of mixture (2).

[0957] 54. Use of at least one high-boiling solvent in a mixture comprising at least one (thio)phosphoric acid derivative and at least one volatile component for preventing decomposition or solids formation of the at least one (thio)phosphoric acid derivative in an evaporation process, wherein in said evaporation process the at least one (thio)phosphoric acid derivative is separated from the at least one volatile component and recovered as the bottom product in the form of a mixture (1) comprising as components

[0958] (1a) the at least one (thio)phosphoric acid derivative; and

[0959] (1b) the at least one high-boiling solvent.

[0960] 55. The use according to embodiment 54, wherein the at least one volatile component comprises at least one solvent having a boiling point, which is at least 30? C. lower than the boiling point of the at least one high-boiling solvent, and optionally at least one HCl scavenger having a boiling point, which is at least 30? C. lower than the boiling point of the at least one high-boiling solvent.

[0961] 56. The use according to embodiment 55, wherein by using the at least one high-boiling solvent in a mixture comprising at least one (thio)phosphoric acid derivative and at least one volatile component, a mixture (2) is formed, which comprises

[0962] (2a) at least one (thio)phosphoric acid derivative;

[0963] (2b) at least one high-boiling solvent;

[0964] (2c) at least one solvent having a boiling point, which is at least 30? C. lower than the boiling point of the at least one high-boiling solvent; and

[0965] (2d) optionally at least one HCl scavenger having a boiling point, which is at least 30? C. lower than the boiling point of the at least one high-boiling solvent,

[0966] and from this mixture (2) mixture (1) is then recovered in said evaporation process.

[0967] 57. The use according to embodiment 54, 55, or 56, wherein the at least one high-boiling solvent is further used as a formulation agent for the at least one (thio)phosphoric acid derivative in the recovered mixture (1).

[0968] 58. A process for recovering at least one (thio)phosphoric acid derivative from a mixture comprising the at least one (thio)phosphoric acid derivative, at least one solvent and optionally at least one HCl scavenger, wherein the process comprises

[0969] adding at least one high-boiling solvent to the mixture so as to form a mixture (2) comprising as components [0970] (2a) at least one (thio)phosphoric acid derivative; [0971] (2b) at least one high-boiling solvent; [0972] (2c) at least one solvent having a boiling point, which is at least 30? C. lower than the boiling point of the at least one high-boiling solvent; and [0973] (2d) optionally at least one HCl scavenger having a boiling point, which is at least 30? C. lower than the boiling point of the at least one high-boiling solvent;

[0974] and separating a mixture (1) from said mixture (2), wherein said mixture (1) comprises as components [0975] (1a) the at least one (thio)phosphoric acid derivative; and [0976] (1b) the at least one high-boiling solvent;

[0977] by evaporating components (2c) and (2d) of mixture (2) and collecting mixture (1) as the bottom product.

[0978] 59. The process according to embodiment 58, wherein evaporating components (2c) and (2d) of mixture (2) and collecting mixture (1) as the bottom product is performed by:

[0979] (i) continuously introducing a stream of the mixture (2) into at least one thin film evaporator operating at a temperature of from 40? C. to 160? C. and at a pressure of from 5 mbar to 300 mbar (0.5 kPa to 30 kPa), and

[0980] (ii) continuously collecting the bottom product,

[0981] wherein preferably the at least one thin film evaporator is operated at a temperature in the range of from 50? C. to 110? C. and at a pressure of from 5 mbar to 250 mbar (0.5 kPa to 25 kPa).

[0982] 60. The process according to embodiment 58 or 59, wherein mixture (2) and mixture (1) as well as its components are defined as in any one of embodiments 2 to 26.

[0983] 61. The process according to any one of embodiments 1 to 28 or the process according to any one of embodiments 58 to 60, wherein the at least one high-boiling solvent is further used as a formulation agent for the at least one (thio)phosphoric acid derivative in the recovered mixture (1).

[0984] 62. The mixture according to any one of embodiments 29 to 53, wherein the at least one high-boiling solvent is further used as a formulation agent for the at least one (thio)phosphoric acid derivative in the recovered mixture (1).

[0985] The present invention is further illustrated by the following examples.

EXAMPLES

Example 1: Preparation of NPPT (Raw Product)

[0986] 169.4 g (1 mol) PSCl.sub.3 and 333.3 g ethyl acetate were precharged at room temperature into a reaction flask and cooled to 0? C. The mixture of 59.7 g (1.01 mol) n-propylamine and 157.6 g (1.1 mol) tri-n-propylamine was added within 90 min. During the addition, the temperature was maintained between 0-2? C. by cooling. The suspension was stirred at 0? C. for additional 60 min and afterwards heated up to 40? C.

[0987] The prepared solution was added within 3 hours parallel to 102.2 g (6 mol) gaseous ammonia (via dip pipe) to 333.3 g ethyl acetate, which was cooled to 6? C. in advance. The temperature was maintained during the addition between 5-7? C.

[0988] The resulting suspension was heated up to 50? C. and filtered at this temperature. The filter cake was washed two times with 200 g ethyl acetate at 50? C.

[0989] After combining the washing solution and the filtrate the light boiler ethyl acetate was distilled off in a thin-film evaporator at 80? C. and 240 mbar. The resulting raw product contained 21% N-propyl thiophosphoryl triamide (NPPT).

Comparative Example 1

[0990] From the raw product obtained according to Example 1, tri-n-propylamine and remaining ethyl acetate were distilled off in a thin-film evaporator at 100? C. and 50 mbar. The raw product was carefully heated to 95? C. slightly above the melting temperature of NPPT for feeding the thin-film evaporator without solid content. At this temperature, the formation of H.sub.2S and a color change of the raw product solution was observed after a short time indicating a decomposition of the NPPT, and no NPPT could be obtained as isolated bottom product.

Comparative Example 2

[0991] From the raw product prepared according to Example 1, tri-n-propylamine and remaining ethyl acetate were removed by applying 1 mbar and 40? C. in a rotary evaporator and a solid product was obtained containing 83% of NPPT.

[0992] However, 1 mbar is not suitable for technical scale. Therefore, it was tested whether the addition of a high-boiling solvent would be suitable for preventing decomposition of NPPT in an evaporation process at higher temperatures.

Example 2

[0993] After recrystallization of the product obtained in Comparative Example 2 in ethyl acetate, the product was mixed with dimethyl sulfoxide to give a 47% NPPT solution, which was heated to 100? C. After keeping the solution for 3 hours at this temperature, no visible signs of NPPT decomposition were observed and the NPPT content was measured to be 47%.

[0994] A mixture comprising NPPT and dimethyl sulfoxide may therefore be used in an evaporation process operating at about 100? C. without decomposition of NPPT.

[0995] The product containing NPPT and dimethyl sulfoxide that will be recovered as a bottom product after an evaporation process is suitable for handling or storage or for being combined with further formulation auxiliaries to provide a suitable formulation of NPPT for treating urea-based fertilizers.

Example 3

[0996] After recrystallization of the product obtained in Comparative Example 2 in ethyl acetate, the product was mixed with propylene glycol to give a 47% NPPT solution, which was heated to 100? C. After keeping the solution for 3 hours at this temperature, no visible signs of NPPT decomposition were observed and the NPPT content was measured to be 47%.

[0997] A mixture comprising NPPT and propylene glycol may therefore be used in an evaporation process operating at about 100? C. without decomposition of NPPT.

[0998] The product containing NPPT and propylene glycol that will be recovered as a bottom product after an evaporation process is suitable for handling or storage or for being combined with further formulation auxiliaries to provide a suitable formulation of NPPT for treating urea-based fertilizers.

Example 4

[0999] After recrystallization of the product obtained in Comparative Example 2 in ethyl acetate, the product was mixed with polyethyleneimine (commercially available under the trade name Agnique? formerly known as Lupasol? from BASF SE) to give a 47% NPPT solution, which was heated to 100? C. After keeping the solution for 3 hours at this temperature no visible signs of NPPT decomposition were observed and the NPPT content was measured to be 47%.

[1000] A mixture comprising NPPT and polyethyleneimine may therefore be used in an evaporation process operating at about 100? C. without decomposition of NPPT.

[1001] The product containing NPPT and polyethyleneimine that will be recovered as a bottom product after an evaporation process is suitable for handling or storage or for being combined with further formulation auxiliaries to provide a suitable formulation of NPPT for treating urea-based fertilizers.

[1002] The polyethyleneimine used in the Example 4 and in the Example 6 is a polyethyleneimine with a weight average molecular weight of 800 g/mol as measured by GPC (dry substance, at pH 4.5).

Example 5

[1003] After recrystallization of the product obtained in Comparative Example 2 in ethyl acetate, the product was mixed with triethanolamine to give a 47% NPPT solution, which was heated to 100? C. After keeping the solution for 3 hours at this temperature no visible signs of NPPT decomposition were observed and the NPPT content was measured to be 47%.

[1004] A mixture comprising NPPT and triethanolamine may therefore be used in an evaporation process operating at about 100? C. without decomposition of NPPT.

[1005] The product containing NPPT and triethanolamine that will be recovered as a bottom product after an evaporation process is suitable for handling or storage or for being combined with further formulation auxiliaries to provide a suitable formulation of NPPT for treating urea-based fertilizers.

Example 6

[1006] 315.2 g of raw product obtained according to Example 1 was mixed with 140.6 g of polyethyleneimine (commercially available under the trade name Agnique? formerly known as Lupasol? from BASF SE) and the mixture carefully heated to 95? C. Tri-n-propylamine and remaining ethyl acetate contained within the raw product were distilled off in a thin-film evaporator at 90-100? C. and 80-90 mbar. No visible signs of NPPT decomposition were observed, and 298 g of product containing 48% NPPT and 47% polyethylene imine collected as the bottom product at the sump of the thin-film evaporator. The purity of NPPT in the resulting product (without consideration of polyethyleneimine) is about 91%.

[1007] The product containing NPPT and polyethyleneimine is suitable for handling or storage or for being combined with further formulation auxiliaries to provide a suitable formulation of NPPT for treating urea-based fertilizers.