Preparation method of copolymerizable photoinitiators
View Patent ↗An intermediate for preparing (meth)acrylated photoinitiators according to Formula (I): wherein: R1 is selected from the group consisting of hydrogen and a methyl group; A represents a group including at least one photoinitiating moiety; L represents a n+o-valent linking group including at least one carbon atom; n and o each independently represent an integer from 1 to 4; p is equal to 0 or 1; X represents a group selected from the group consisting of Cl, Br, I, and R 2 SO 3 ; and R 2 represents an optionally substituted group selected from the group consisting of an alkyl group, an alkenyl group, an alkynyl group, an alkaryl group, an aralkyl group, an aryl group and a heteroaryl group. Also, a method for the preparation of (meth)acrylated photoinitiators by β-elimination of HX from the intermediate according to Formula (I).
1. A method for the preparation of (meth)acrylated photoinitiators comprising the steps of:
A) preparing an intermediate according to Formula (I) by reacting a starting material according to Formula (II) with an acid chloride according to Formula (III) in an aprotic solvent using an inorganic base or a salt of a carboxylic acid:
wherein:
R1 is selected from the group consisting of hydrogen and a methyl group;
A represents a group including at least one photoinitiating moiety selected from the group consisting of benzil ketals, α,α-dialkoxyacetophenones, α-hydroxyalkylphenones, α-aminoalkylphenones, acylphosphine oxides, bis-acylphosphine oxides, acylphosphine sulfides, α-haloketones, α-halosulfones, phenylglyoxalates, benzophenones, thioxanthones, and 1,2-diketones;
L represents a n+o-valent linking group including at least one carbon atom;
n and o each independently represent an integer from 1 to 4;
p is equal to 0 or 1;
X represents a group selected from the group consisting of Cl, Br, I, and R 2 SO 3 ; and
R 2 represents an optionally substituted group selected from the group consisting of an alkyl group, an alkenyl group, an alkynyl group, an alkaryl group , an aralkyl group, an aryl group, and a heteroaryl grou; and
B) forming a (meth)acrylated photoinitiator by β-elimination of HX from the intermediate according to Formula (I).
2. The method according to claim 1 , wherein the linking group L contains not more than 20 carbon atoms.
3. The method according to claim 1 , wherein n and o are equal to 1.
4. The method according to claim 1 , wherein the linking group L links the photoinitiating moiety A to the oxygen atom via a functional group selected from the group consisting of an ester, an amide, an ether, a thioether, and an amine.
5. The method according to claim 1 , wherein the linking group L is selected from the group consisting of a substituted or unsubstituted alkylene group, a substituted or unsubstituted arylene group, and a substituted or unsubstituted heteroarylene group.
6. The method according to claim 5 , wherein the linking group L is an alkylene group.
7. The method according to claim 1 , wherein A represents a group including at least one photoinitiating moiety having an acid sensitive functional group.
8. The method according to claim 1 , wherein the inorganic base is selected from the group consisting of a carbonate salt, a bicarbonate salt, a borate salt, a phosphate salt, and a hydrogen phosphate salt.
9. The method according to claim 1 , wherein the inorganic base or the salt of a carboxylic acid is a potassium salt.
10. The method according to claim 9 , wherein the inorganic base is potassium carbonate.
11. The method according to claim 1 , wherein the aprotic solvent is selected from the group consisting of aliphatic ketones, aliphatic nitriles, cyclic ethers, aliphatic esters, aliphatic ethers, glycol ethers, glycol esters, dimethyl acetamide, dimethyl formamide, N-methyl pyrrolidone, dimethyl sulfoxide, sulfolane, lactones, halogenated hydrocarbons, aromatic hydrocarbons, and aliphatic hydrocarbons.