Production of SiOC-bonded polyether siloxanes
SiOC-bonded polyether siloxanes are produced by transesterification of alkoxysiloxanes with polyetherols in the presence of trifluoromethanesulfonate as catalyst. The computational total water content of the reactants including alkoxysiloxanes and polyetherols is ≤5000 ppm by mass, advantageously ≤300 ppm by mass, preferably ≤150 ppm by mass, more preferably ≤100 ppm by mass, in particular ≤50 ppm by mass. The determination of the individual water contents is performed beforehand, preferably by titration according to Karl Fischer.
1. A process for producing a SiOC-bonded polyether siloxane, comprising:
transesterifying an alkoxysiloxane with a polyetherol in the presence of a trifluoromethanesulfonate salt as a catalyst comprising a metal trifluoromethanesulfonate according to formula (I):
[CF3SO3] x [M] x+ formula (1),
wherein M is a metal atom selected from the group consisting of zinc, bismuth, aluminium, and iron,
or
selected from the group consisting of sodium and potassium, with the proviso that methanesulfonic acid is present, and
x is a number up to a maximum valency of the metal atom selected for M
wherein a computational total water content of reactants consisting of the alkoxysiloxane and the polyetherol is <5000 ppm by mass, wherein determination of an individual water content is performed before the transesterifying.
2. The process according to claim 1 , wherein the catalyst is employed in an amount of 0.01 to 1.0 percent by weight based on a mass of a reaction matrix consisting of the polyetherol and the alkoxysiloxane.
3. The process according to claim 1 , wherein the polyetherol is employed in an amount of in each case 0.8 to 2.0 OH-equivalents, based on every alkoxy group bonded to a silicone skeleton of the alkylsiloxane.
4. The process according to claim 1 , wherein the alkoxysiloxane conforms to at least one of formulae (II) to (VI):
wherein R 1 =alkyl and/or aralkyl and/or aromatic radical comprising 1 to 10 carbon atoms,
R=alkyl radical comprising 1 to 8 carbon atoms, and
wherein 1≤n≤250, and/or
wherein R 1 =alkyl and/or aralkyl and/or aromatic radical comprising 1 to 10 carbon atoms,
R=alkyl radical comprising 1 to 8 carbon atoms,
wherein 1≤a≤60, and
wherein 0<b≤10, and/or
wherein R 1 =alkyl and/or aralkyl and/or aromatic radical comprising 1 to 10 carbon atoms,
R=alkyl radical comprising 1 to 8 carbon atoms,
wherein 0≤x≤250, and
wherein 1≤y≤50, and/or
wherein R 1 =alkyl and/or aralkyl and/or aromatic radical comprising 1 to 10 carbon atoms,
R=alkyl radical comprising 1 to 8 carbon atoms,
wherein 0≤x≤250, and
1≤y≤50, and/or
wherein R 1 =alkyl and/or aralkyl and/or aromatic radical comprising 1 to 10 carbon atoms,
R=alkyl radical comprising 1 to 8 carbon atoms,
wherein 4≤(k+1)≤5, and
1≥1.
5. The process according to claim 4 , wherein the alkoxysiloxane is at least one of formula (II) and/or formula (III).
6. The process according to claim 1 , wherein the polyetherol is of formula (VII):
A[-O—(CH 2 —CHR′—O—) m —(CH 2 —CH 2 —O—) n —(CH 2 —CH(CH 3 )—O—) o -Z] a formula (VII)
wherein
A is either hydrogen or at least one carbon atom-comprising saturated or unsaturated organic radical,
R′ is independently at each occurrence a saturated alkyl group comprising 2-18 carbon atoms or an aromatic radical,
Z is hydrogen,
m=from 0 to 50,
n=from 0 to 250,
o=from 0 to 250, and
a=from 1 to 8,
with the proviso that a sum of m, n, and o is equal to or greater than 1.
7. The process according to claim 6 , wherein the polyetherol of formula (VII) consists of hydrogen atoms, oxygen atoms, and carbon atoms.
8. The process according to claim 1 , wherein the transesterifying of the alkoxysiloxane is performed without a use of solvents.
9. The process according to claim 1 , wherein the transesterifying of the alkoxysiloxane is performed in a solvent inert under reaction conditions, wherein a total water content of the solvent is ≤50 ppm by mass, and wherein the determination of the total water content of solvent is determined by Karl Fischer titration.
10. The process according to claim 1 , wherein the transesterifying is performed in a temperature range of 80° C. to 180° C.
11. The process according to claim 1 , wherein the transesterifying is performed at reduced pressure and with passing through of an inert gas.
12. A product, comprising:
the SiOC-bonded polyether siloxane produced according to claim 1 , whose polyether portion is derived from alkoxylation of an unsaturated starter alcohol, as PU foam stabilizer, defoamer and/or deaerator and also as defoamer and/or deaerator components in paint and binder systems.
13. The process according to claim 1 , wherein the computational total water content of the reactants consisting of the alkoxysiloxane and the polyetherol is ≤50 ppm by mass, and wherein the determination of the individual water content is performed beforehand by Karl Fischer titration.
14. The process according to claim 2 , wherein the catalyst is employed in an amount of 0.07 to 0.8 percent by weight, based on the mass of the reaction matrix.
15. The process according to claim 3 , wherein the polyetherol is employed in an amount of in each case 0.8 to 1.3 OH-equivalents, based on every alkoxy group bonded to the silicone skeleton.
16. The process according to claim 6 , wherein
A is at least one carbon atom-comprising organic radical of an organic starter compound for preparing the polyetherol, selected from the group consisting of a methyl, ethyl, propyl, butyl, vinyl, and allyl group,
R′ is independently at each occurrence an ethyl group or a phenyl radical,
m=from 0 to 20,
n=from 5 to 200,
o=from 5 to 200, and
a=from 1, 2, 3 or 4.
17. The process according to claim 9 ,
wherein the solvent is at least one selected from the group consisting of toluene and xylene, in pure form or as an isomer mixture,
wherein the solvent is employed in total amounts of 5% to 35% by weight based on the mass of the reaction matrix, and
wherein the total water content of the solvent is ≤10 ppm by mass.
18. The process according to claim 10 , wherein the transesterifying is performed in a temperature range of 110° C. to 150° C.
19. The product according to claim 12 , wherein the unsaturated starter alcohol is allyl alcohol.
20. The process according to claim 1 , wherein the catalyst consists of a metal trifluoromethanesulfonate according to formula (I):
[CF 3 SO 3 − ] x [M] x+ formula (I),
wherein M is a metal atom selected from the group consisting of zinc, bismuth, aluminium, and iron,
or
selected from the group consisting of sodium and potassium, with the proviso that methanesulfonic acid is present,
and x is a number up to a maximum valency of the metal atom selected for M.
21. The process according to claim 1 , wherein the catalyst consists of a metal trifluoromethanesulfonate according to formula (I):
[CF 3 SO 3 − ] x [M] x+ formula (I),
wherein M is a metal atom selected from the group consisting of zinc, bismuth, aluminium, and iron, and x is a number up to a maximum valency of the metal atom selected for M.
22. The process according to claim 1 , wherein the catalyst consists of zinc triflate.
23. The process according to claim 1 , wherein the catalyst consists of sodium triflate and methanesulfonic acid or potassium triflate and methanesulfonic acid.
24. The process according to claim 1 , wherein the catalyst comprises a metal trifluoromethanesulfonate according to formula (I):
[CF 3 SO 3 − ] x [M] x+ formula (I),
wherein M is a metal atom selected from the group consisting of zinc, bismuth, aluminium, and iron, and x is a number up to a maximum valency of the metal atom selected for M.