Process for preparing alkylaminoalkylalkoxysilanes
A process for preparing an alkylamino-alkylalkoxysilane of formula (I) R—(NR′)—Y—Si(R 1 ) n (OR 2 ) 3-n (I) in which R is a linear, branched or cyclic alkyl group having 1 to 12 carbon atoms, R′ is a hydrogen (H) or is a linear, branched or cyclic alkyl group having 1 to 12 carbon atoms, Y is a bivalent alkyl group from the group of —CH 2 —, —(CH 2 ) 2 —, —(CH 2 ) 3 —, —(CH 2 )(CH(CH 3 ))(CH 2 )— and —(CH 2 ) 4 —, R 1 and R 2 groups are the same or different and are each a linear or branched alkyl group having 1 to 4 carbon atoms, and n is 0 or 1 or 2, by reacting an alkylamine, used in excess, distilling off excess free alkylamine, treating the remaining product mixture with the alkylaminoalkylalkoxysilane and working up.
1. A process for preparing an alkylaminoalkylalkoxysilane of formula I
R—(NR′)—Y—Si(R 1 ) n (OR 2 ) 3-n (I),
wherein
R is a linear, branched, or cyclic alkyl group having 1 to 12 carbon atoms,
R′ is a hydrogen (H) or a linear, branched, or cyclic alkyl group having 1 to 12 carbon atoms,
Y is a bivalent alkyl group selected from the group consisting of —CH 2 —, —(CH 2 ) 2 —, —(CH 2 ) 3 , —(CH 2 )(CH(CH 3 ))(CH 2 )—, and —(CH 2 ) 4 —,
R 1 and R 2 groups are the same or different and are each a linear or branched alkyl group having 1 to 4 carbon atoms, and
n is 0, 1, or 2,
the method comprising:
(A) reacting an alkylamine of formula II, in excess,
R(NR′)H (II),
wherein R is a linear, branched, or cyclic alkyl group having 1 to 12 carbon atoms, and
R′ is a hydrogen (H) or a linear, branched or cyclic alkyl group having 1 to 12 carbon atoms,
with a haloalkylalkoxysilane of formula III
X—Y—Si(R 1 ) n (OR 2 ) 3-n (III),
wherein
X is Cl or Br,
Y is a bivalent alkyl group selected from the group consisting of —CH 2 —, —(CH 2 ) 2 —, —(CH 2 ) 3 —, —(CH 2 )(CH(CH 3 ))(CH 2 )—, and —(CH 2 ) 4 —,
R 1 and R 2 groups are the same or different and are each a linear or branched alkyl group having 1 to 4 carbon atoms, and
n is 0, 1, or 2;
(B) distilling off excess alkylamine from a remaining product mixture;
(C) at the same time, adding the alkylaminoalkylalkoxysilane to the remaining product mixture, comprising alkylamine hydrohalide and alkylaminoalkylalkoxysilane hydrohalide, and removing the alkylamine released as a result from the mixture, to give a remaining product or product hydrohalide mixture and
(D) working up the remaining product or product hydrohalide mixture.
2. The process according to claim 1 , wherein the working up (D) comprises:
heat treating;
reacting with an alkali metal alkoxide solution;
precipitating and removing alkali metal halide formed, to give a product solution; and
removing solvent introduced with the alkali metal alkoxide solution from the product solution by distillation to obtain the alkylaminoalkylalkoxysilane.
3. The process according to claim 1 , wherein the working up (D) comprises:
adding a nonpolar organic solvent;
treating the mixture with an aqueous alkali metal or alkaline earth metal hydroxide solution, to give a resulting aqueous phase comprising metal salt and an organic phase;
separating the resulting aqueous phase containing metal salt from the organic product phase; and
distilling the organic phase to obtain the alkylaminoalkylalkoxysilane.
4. The process according to claim 1 , wherein the alkylaminoalkylalkoxysilane obtained is recycled partly into the process to release the corresponding alkylamine from the alkylamine hydrohalide.
5. The process according to claim 1 , wherein alkylamine recovered is recycled as a reactant component.
6. The process according to claim 1 , wherein the alkylamine of formula II is methylamine, ethylamine, n-propylamine, n-butylamine, 2-heptylamine, 2-butylamine, n-pentylamine, 2-pentylamine, 3-pentylamine, n-hexylamine, n-heptylamine, octylamine, 2-octylamine, nonylamine, decylamine, undecylamine, or dodecylamine.
7. The process according to claim 1 , wherein the haloalkylalkoxysilane of formula III is 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 3-chloroisobutyltrimethoxysilane, 3-chloroisobutyltriethoxysilane, 2-chloroethyltrimethoxysilane, 2-chloroethyltriethoxysilane, 1-chloromethyltrimethoxysilane, 1-chloromethyltriethoxysilane, chloropropylmethyldimethoxysilane, chloropropylmethyldiethoxysilane, chloropropyldimethylmethoxysilane, chloropropyldimethylethoxysilane, chloroisobutylmethyldimethoxysilane, chloroisobutyldimethylmethoxysilane, chloroisobutyldimethylethoxysilane, chloroisobutyldimethyldiethoxysilane, chloroethylmethyldimethoxysilane, chloroethylmethyldiethoxysilane, chloroethyldimethylmethoxysilane, chloroethyldimethylethoxysilane, chloromethylmethyldimethoxysilane, chloromethylmethyldiethoxysilane, chloromethyldimethylmethoxysilane, or chloromethyldimethylethoxysilane.
8. The process according to claim 1 , wherein the alkylamine and the haloalkylalkoxysilane are present in the reacting (A) in a molar ratio of 1.1:1 to 10:1.
9. The process according to claim 1 , wherein the reacting is performed at a temperature of 60 to 200° C. and a pressure of 0.1 to 20 bar, and over a duration of 30 minutes to 16 hours.
10. The process according to claim 1 , wherein the alkylaminoalkylalkoxysilane obtained is 3-(n-butylamino)propyltrimethoxysilane or 3-(n-butylamino)propyltriethoxysilane.
11. The process according to claim 2 , wherein the alkylaminoalkylalkoxysilane obtained is recycled partly into the process to release the corresponding alkylamine from the alkylamine hydrohalide.
12. The process according to claim 3 , wherein the alkylaminoalkylalkoxysilane obtained is recycled partly into the process to release the corresponding alkylamine from the alkylamine hydrohalide.
13. The process according to claim 2 , wherein alkylamine recovered is recycled as a reactant component.
14. The process according to claim 3 , wherein alkylamine recovered is recycled as a reactant component.
15. The process according to claim 4 , wherein alkylamine recovered is recycled as a reactant component.
16. The process according to claim 11 , wherein alkylamine recovered is recycled as a reactant component.
17. The process according to claim 12 , wherein alkylamine recovered is recycled as a reactant component.
18. The process according to claim 2 , wherein the alkylamine of formula II is methylamine, ethylamine, n-propylamine, n-butylamine, 2-heptylamine, 2-butylamine, n-pentylamine, 2-pentylamine, 3-pentylamine, n-hexylamine, n-heptylamine, octylamine, 2-octylamine, nonylamine, decylamine, undecylamine, or dodecylamine.
19. The process according to claim 3 , wherein the alkylamine of formula II is methylamine, ethylamine, n-propylamine, n-butylamine, 2-heptylamine, 2-butylamine, n-pentylamine, 2-pentylamine, 3-pentylamine, n-hexylamine, n-heptylamine, octylamine, 2-octylamine, nonylamine, decylamine, undecylamine, or dodecylamine.
20. The process according to claim 4 , wherein the alkylamine of formula II is methylamine, ethylamine, n-propylamine, n-butylamine, 2-heptylamine, 2-butylamine, n-pentylamine, 2-pentylamine, 3-pentylamine, n-hexylamine, n-heptylamine, octylamine, 2-octylamine, nonylamine, decylamine, undecylamine, or dodecylamine.