Method for preparing amino alkyl(meth)acrylates
View Patent ↗A process for the preparation of aminoalkyl (meth)acrylates by transesterification from C 1 –C 4 -alkyl (meth)acrylates and aminoalcohols is described, in which process the transesterification is carried out in the presence of at least one distannoxane of the general formula (1) wherein R=linear, cyclic or branched alkyl radical having from 1 to 6 carbon atoms, phenyl radical, and the radicals R may be identical or different from one another, Y=halogen, preferably Cl, Br; pseudo-halogen, preferably SCN; OH, OAc or OR, the radicals Y being identical or different from one another, as catalyst, and the use of the aminoalkyl (meth)acrylates prepared according to the process in the preparation of cationic monomers.
1. A process for producing aminoalkyl (meth)acrylates, comprising:
transesterifying one or more C 1 –C 4 -alkyl (meth)acrylates and one or more aminoalcohols in the presence of a catalytically effective amount of at least one distannoxane of formula (1):
to form one or more aminoalkyl (meth)acrylates,
wherein
each Y is, independently, a pseudo-halogen other than SCN, and
each R is, independently, a linear, cyclic or branched alkyl radical having from 1 to 6 carbon atoms or phenyl radical.
2. The process according to claim 1 , wherein said at least one distannoxane is selected from the group consisting of diisopropyldibutyltetrachlorodistannoxane, diisopropyldimethyltetrachlorodistannoxane, dibutyldioctyltetrachlorodistannoxane, dimethyldioctyltetrachlorodistannoxane, dimethyldibutyltetrachlorodistannoxane and octabutyltetrachlorodistannoxane.
3. The process according to claim 1 , wherein the distannoxane is octabutyltetrachlorodistannoxane.
4. The process according to claim 1 , wherein the distannoxane is present in an amount of from 0.1 to 10 mmol, per mol of aminoalcohol.
5. The process according to claim 1 , wherein the aminoalcohols are dialkylaminoalcohols.
6. The process according to claim 5 , wherein the dialkylaminoalcohol is selected from the group consisting of dimethylaminoethanol, dimethylaminopropanol, diethylaminoethanol and diethylaminopropanol.
7. The process according to claim 1 , wherein the transesterification is carried out in the presence of one or more polymerization inhibitors.
8. The process according to claim 7 , wherein the polymerization inhibitor is phenothiazine.
9. The process according to claim 1 , wherein the transesterification takes place at a pressure in the range from 100 to 1100 mbar.
10. The process according to claim 1 , further comprising working-up the aminoalkyl (meth)acrylates in a continuous distillation process to produce a low-boiling fraction, and feeding back the low-boiling fraction.
11. The process according to claim 10 , in which is base fraction is produced and wherein from 1 to 100% of the base fraction is fed back into the transesterification.
12. The process according to claim 10 , wherein in the continuous working up, high-boiling components are first separated off in a distillation step in which the residence time under a thermal load is less than 10 minutes.
13. The process according to claim 1 , wherein the distannoxane is present in an amount of from 0.2 to 1 mmol per mol of aminoalcohol.
14. The process according to claim 10 , wherein from 25 to 95% of a base fraction is fed back into the reaction.
15. The process according to claim 10 , wherein from 50 to 90% of a base fraction is fed back into the reaction.
16. The process according to claim 10 , wherein in the continuous working up, the high-boiling components are first separated off in a distillation step in which the residence time under a thermal load is less than 1 minute.