Preparation of (meth)acrylic esters of polyalkoxy-containing alcohols
In a process for preparing (meth)acrylic esters (E) of polyalkoxy-containing alcohols which comprises reacting polyalkoxy-containing alcohols (P) of formula (I) where R 1 is hydrogen, a hydroxyl group or a straight-chain or branched, saturated or unsaturated alcohol of 1 to 30 carbon atoms, R 2 and R 3 are each independently H or methyl, and m and n are each independently an integer between 0 and 100, with the proviso that m and n cannot both be 0, with a (meth)acrylic anhydride (A) in the presence of at least one basic catalyst (K) having a pK B value of not more than 7.0 and of at least one sterically hindered polymerization inhibitor, the reaction mixture is quenched with a C 1 -C 6 alkanol after the reaction has ended.
1. A process for preparing a (meth)acrylic ester (E) of a polyalkoxy-containing alcohol, the process comprising reacting a polyalkoxy-containing alcohol (P) of formula (I)
wherein
R 1 is hydrogen, a hydroxyl group or a straight-chain or branched, saturated or unsaturated alcohol of 1 to 30 carbon atoms,
R 2 and R 3 are each independently H or methyl, and
m and n are each independently an integer between 0 and 100, with the proviso that m and n cannot both be 0,
with a (meth)acrylic anhydride (A) in the presence of a basic catalyst (K) having a pK B value of not more than 7.0 and of a sterically hindered polymerization inhibitor,
wherein the reaction mixture is quenched with a C 1 -C 6 alkanol after the reaction has ended.
2. The process according to claim 1 , wherein R 2 and R 3 are each hydrogen in formula (I).
3. The process according to claim 1 , wherein m and n in formula (I) are each independently integers in the range from 5 to 90.
4. The process according to claim 3 , wherein m and n in formula (I) are each independently integers in the range from 5 to 50.
5. The process according to claim 1 , wherein the substituent R 1 is a straight-chain, saturated or unsaturated primary alcohol of 6 to 22 carbon atoms.
6. The process according to claim 1 , wherein the basic catalyst (K) has a pK B value of not more than 3.0.
7. The process according to claim 6 , wherein the basic catalyst is selected from the group consisting of alkali metal and alkaline earth metal hydroxides and inorganic salts.
8. The process according to claim 7 , wherein the basic catalyst is lithium hydroxide, sodium hydroxide, potassium hydroxide, magnesium hydroxide or calcium hydroxide.
9. The process according to claim 7 , wherein the inorganic salt comprises at least one anion selected from the group consisting of carbonate (CO 3 2− ), bicarbonate (HCO 3− ), phosphate (PO 4 3− ), hydrogenphosphate (HPO 4 2− ), dihydrogenphosphate (H 2 PO 4− ), sulfate (SO 4 2− ), sulfite (SO 3 2− ) and carboxylate (R 4 —COO—), where R 4 is C 1 -C 18 alkyl; C 2 -C 18 alkyl optionally interrupted by an oxygen atom, a sulfur atom, a substituted or unsubstituted imino group, or any combination thereof; or C 6 -C 14 aryl.
10. The process according to claim 9 , wherein the inorganic salt is selected from the group consisting of Li 3 PO 4 , K 3 PO 4 , Na 3 PO 4 , K 2 CO 3 and Na 2 CO 3 and also hydrates thereof.
11. The process according to claim 1 , wherein the amount of (meth)acrylic anhydride (A) is reacted at not more than 1.35 mol per mole of the polyalkoxy-containing alcohol (P).
12. The process according to claim 11 , wherein the amount of (meth)acrylic anhydride (A) is reacted at not more than 1.15 mol per mole of the polyalkoxy-containing alcohol (P).
13. The process according to claim 1 wherein the sterically hindered polymerization inhibitor does not degrade during the course of the reaction.
14. The process according to claim 13 , wherein the sterically hindered polymerization inhibitor is selected from the group consisting of 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-4-methylphenol and phenothiazine.
15. The process according to claim 1 , wherein the C 1 -C 6 alkanol is selected from the group consisting of methanol, ethanol, propanol and isopropanol.
16. The process according to claim 15 , wherein the C 1 -C 6 alkanol is selected from the group consisting of methanol and ethanol.
17. The process according to claim 1 , wherein the quench time is up to 2 h, but not less than 30 minutes.
18. The process according claim 1 , wherein the C 1 -C 6 alkanol is added to the reaction medium in amounts of up to 5 wt %, based on total reaction medium.
19. A method for producing a dispersion, comprising employing a (meth)acrylic ester (E) of a polyalkoxy-containing alcohol as a monomer or comonomer.