CN101624408A - Pendant naphthalene group-containing benzene ligand ferrocenium salt cationic photoinitiators and preparation method thereof - Google Patents

Abstract

The invention discloses a class of cyclopentadiene-iron-benzoferrocene salt compounds containing naphthyloxy side groups. The compounds are used as photoinitiators for cationic photopolymerization and belong to the technical fields of organic synthesis and cationic photopolymerization. The preparation of this type of compound is divided into two steps. Firstly, ferrocene and chlorobenzene are used as raw materials, and a ligand exchange reaction occurs under the catalysis of Lewis acid to obtain cyclopentadiene-iron-chlorobenzene salt, and then through alkaline environment and The corresponding naphthol compound undergoes a nucleophilic substitution reaction to introduce a naphthyloxy side group on the benzene ligand. This type of compound has excellent ultraviolet absorption performance and photoinitiating activity, can initiate photopolymerization of epoxy compounds and alkenyl ether compounds, and has extensive research potential and application prospects in the field of photocuring applications.

Description

Benzene ligand ferrocene salt cationic photoinitiator of naphthyloxy side group and preparation method thereof

technical field

The invention relates to a benzene ligand ferrocene hexafluorophosphate cationic photoinitiator containing a naphthyloxy side group and a preparation method thereof, belonging to the technical fields of organic synthesis and cationic photopolymerization.

Background technique

Since Crivello et al. successfully studied the cationic photopolymerization initiating activity of diaryl iodonium salt and triaryl sulfonium salt in the 1970s, the research and application of cationic photopolymerization have made great progress. Compared with the radical photocuring system, the cationic photocuring system has the advantages of photoinitiated cationic monomers and prepolymers, and is not free from oxygen inhibition and active polymerization. Compared with the many types of free radical photoinitiators used in free radical photopolymerization systems that have been developed more maturely, there are fewer types of initiators for cationic photopolymerization, and the commonly used cationic photoinitiators are diaryl iodide Onium salts and triarylsulfonium salts. The absorption peaks of these two types of compounds in the ultraviolet-visible absorption spectrum are below 300nm, and there is almost no absorption above 300nm, so they cannot match some commonly used light sources such as high-pressure mercury lamps.

In the mid-1980s, F.Lohse et al. of Ciba Company developed the cationic photoinitiator of aryl ferrocenium salt. The photoinitiating mechanism of this kind of substance is different from that of diaryl iodonium salt and triaryl sulfonium salt. The species with initiating activity is the divalent iron ion generated by taking off the arene ligand after the photolysis of the ferrocene salt. Arylferrocene has good thermal stability, and its absorption peaks generated by the d-d transition are located in the near ultraviolet and visible light regions, so it can be matched with long-wave ultraviolet light sources, such as high-pressure mercury lamps. The study found that the photoinitiation activity of the simple benzene ligand ferrocene salt is poor. By introducing a fused ring ligand, the characteristic ultraviolet absorption peak of the ferrocene salt can be shifted to the long wavelength direction, and the light absorption can be increased, thereby improving the photoinitiation activity of the ferrocene salt. trigger activity.

Contents of the invention

The purpose of the present invention is to prepare a kind of benzene ligand ferrocene salt novel cationic photoinitiator containing naphthyl oxygen side group, this initiator has good absorption in long wavelength region, molar extinction coefficient is higher, in cationic photopolymerization have high photoinitiating activity.

The invention discloses a class of ferrocene salt compounds containing naphthyloxy side groups, which are characterized in that the general chemical structure formula is as follows:

In the structural formula, the oxygen atom is located at the α or β position of the naphthalene ring, R is H or C=1-14 alkyl, substituted alkyl, halogen atom, carboxyl, etc., MXn ^- is a non-nucleophilic anion: SbF ₄ ^- , AsF ₆ ^- , PF ₆ ^- , BF ^- ₄ , CF ₃ SO ₃ ^- or CH ₃ SO ₃ ^- .

When the oxygen atom is located at the α position of the naphthalene ring, and R is H, MXn ^- is PF ₆ ^- , and the compound is a benzene ligand ferrocene hexafluorophosphate with α-naphthyloxy side group, and its structural formula is:

When the oxygen atom is located at the β position of the naphthalene ring, and R is H, MXn ^- is PF ₆ ^- , and the compound is a benzene ligand ferrocene hexafluorophosphate with a β-naphthalene oxygen side group, and its structural formula is:

The preparation method of the benzene ligand ferrocene hexafluorophosphate compound containing α-naphthyloxy side group is as follows:

(1) Cyclopentadiene-iron-chlorobenzene salt (I) is prepared by reacting ferrocene and chlorobenzene under Lewis acid catalysis. The reaction formula is:

The reaction conditions are: add 0.05mol ferrocene, 0.15mol anhydrous AlCl ₃ , 0.15mol aluminum powder and 10ml chlorobenzene in a 250ml three-necked flask, use 50ml cyclohexane as solvent, stir, heat and reflux for 10 hours to obtain the compound (I).

(2) add NaMXn or KMXn reaction and make product (II) cyclopentadiene-iron-chlorobenzene salt by product (I) hydrolysis, reaction formula is:

The reaction conditions are as follows: slowly add methanol to the product (I), then pour the reaction mixture into a beaker equipped with ice water, fully stir, filter, and separate liquids. The organic phase was extracted with a small amount of water, and the aqueous phases were combined, and then an excessive amount of KPF ₆ aqueous solution was added thereto, and the precipitated yellow solid was the crude product. After the solid is dried, the compound (II) is obtained by purification.

(3) by product (II) under alkaline condition and α-naphthol generation nucleophilic substitution reaction makes product (III) the benzene ligand ferrocene salt containing α-naphthyl oxygen side group, reaction formula is as follows:

The reaction conditions are: 0.01mol compound (II) and 0.02mol α-naphthol are dissolved in N,N-dimethylformamide, react for 9-11 hours under the catalysis of 0.02mol potassium carbonate, add 15% hydrochloric acid to adjust to Acidic, filtered with suction, added saturated KPF ₆ aqueous solution to obtain a yellow crude product. Drying, column chromatography purification to obtain product (III) benzene ligand ferrocene hexafluorophosphate with α-naphthyloxy side group.

The preparation method of the benzene ligand ferrocene hexafluorophosphate compound containing β-naphthyloxy side group is to produce the product (IV) containing β-naphthol through the nucleophilic substitution reaction of the product (II) under alkaline conditions The benzene ligand ferrocene salt of naphthyloxy side group, the reaction formula is as follows:

The reaction conditions are: 0.01mol compound (II) and 0.02mol β-naphthol are dissolved in N, N-dimethylformamide, react for 7-9 hours under the catalysis of 0.02mol potassium carbonate, add 15% hydrochloric acid to adjust To acid, filter with suction, add saturated KPF ₆ aqueous solution to obtain a yellow crude product. Drying, column chromatography purification to obtain product (IV) benzene ligand ferrocene hexafluorophosphate of β-naphthyloxy side group.

The advantage of the present invention is that the benzene ligand ferrocene salt containing naphthyloxy side group is a kind of cationic photocuring initiator which is easy to prepare and has strong absorption above 300nm. Effectively initiates photopolymerization of epoxies and vinyl ethers.

The structure of the ultraviolet absorption test shows that the benzene ligand ferrocene salt containing the naphthyloxy side group prepared by the present invention has strong absorption in the near ultraviolet region; the test results of its photoinitiation performance by using a long-wavelength ultraviolet light source such as a high-pressure mercury lamp show that, This type of ferrocene compound has excellent photoinitiating activity.

The present invention utilizes the method for the photoinitiation performance of on-line infrared test ferrocene salt compound as follows (below all represent with weight fraction):

Mix 1-3 parts of benzene ligand ferrocene salt containing naphthyloxy side group and 100 parts of alicyclic epoxy compound ERL4221 evenly, take a small amount and sandwich it with two pieces of potassium bromide salt to form a film with a fixed thickness, and put it on On the sample stage, irradiate with a 365nm light source and detect with infrared spectroscopy.

Description of drawings

Figure 1 is the ultraviolet absorption spectrum of ferrocene hexafluorophosphate containing naphthyloxy side groups at a concentration of 1×10 ^-4 mol/L in dichloromethane.

Fig. 2 is the photoinitiation curve of the alicyclic epoxy compound ERL4221 detected by two kinds of 3%w ferrocene hexafluorophosphate containing naphthyloxy side groups by PHOTO-IR.

Fig. 3 is the infrared spectrogram of benzene ligand ferrocene hexafluorophosphate with α-naphthyloxy side group.

Fig. 4 is the infrared spectrogram of benzene ligand ferrocene hexafluorophosphate with β-naphthyloxy side group.

Detailed ways

The following examples are to further illustrate the present invention, but not to limit the scope of the present invention.

Embodiment 1 prepares cyclopentadiene-iron-chlorobenzene hexafluorophosphate

Add 0.05 mol ferrocene, 0.15 mol anhydrous AlCl ₃ , 0.15 mol aluminum powder and 10 ml chlorobenzene into a 250 ml three-necked flask under the protection of N ₂ , use 50 ml cyclohexane as solvent, stir, and maintain heating and reflux for 10 hours.

After the reaction solution is cooled, slowly add 10% methanol to the reaction solution, then pour the reaction mixture into a beaker filled with ice water, fully stir, filter, separate liquids, wash the organic phase with water, and combine with the water phase, Repeated washing with cyclohexane, and then adding excess KPF6 aqueous solution that is a yellow precipitate. After the solid was dried, it was purified by column chromatography to obtain cyclopentadiene-iron-chlorobenzene hexafluorophosphate with a yield of 40%.

Example 2 Preparation of benzene ligand ferrocene hexafluorophosphate of α-naphthyloxy side group

Under the protection of N ₂ , in a 100ml round bottom flask, 0.01mol cyclopentadiene-iron-chlorobenzene hexafluorophosphate and 0.02mol α-naphthol were dissolved in 10ml N,N-dimethylformamide, in 0.02mol potassium carbonate The reaction was carried out under the catalysis of the reaction solution for 9 hours. After the reaction was completed, 15% hydrochloric acid was added to make it acidic, filtered by suction, and a saturated KPF ₆ aqueous solution was added to obtain a yellow crude product. Drying, column chromatography purification to obtain the benzene ligand ferrocene hexafluorophosphate of α-naphthyloxy side group, the yield is 85%.

Example 3 Preparation of benzene ligand ferrocene hexafluorophosphate of β-naphthyloxy side group

Under the protection of N ₂ , in a 100ml round bottom flask, 0.01mol cyclopentadiene-iron-chlorobenzene hexafluorophosphate and 0.02mol β-naphthol were dissolved in 10ml N,N-dimethylformamide, in 0.02mol potassium carbonate The reaction was carried out under the catalysis of 15% hydrochloric acid for 7 hours, adjusted to acidity by adding 15% hydrochloric acid, filtered by suction, and saturated KPF ₆ aqueous solution was added to obtain a yellow crude product. Drying, column chromatography purification to obtain the benzene ligand ferrocene hexafluorophosphate of the product β-naphthyloxy side group, the yield is 88%.

Claims (5)

1 one classes contain the luxuriant molysite compound of naphthalene oxygen side group, it is characterized in that chemical structure of general formula as shown in the formula:

Sauerstoffatom is positioned at the α or the β position of naphthalene nucleus in the structural formula, and R is alkyl, substituted alkyl, halogen atom, carboxyl of H or C=1-14 etc., MXn ^-Be non-nucleophilicity negatively charged ion: SbF ₄ ^-, AsF ₆ ^-, PF ₆ ^-, BF ^- ₄, CF ₃SO ₃ ^-Or CH ₃SO ₃ ^-

2 compounds according to claim 1 are worked as the α position that Sauerstoffatom is positioned at naphthalene nucleus especially, when R is H, and MXn ^-Be PF ₆ ^-, this compound is the luxuriant iron hexafluorophosphate of the benzene part of alpha-naphthoxy side group, structural formula is:

3 compounds according to claim 1 are worked as the β position that Sauerstoffatom is positioned at naphthalene nucleus especially, when R is H, and MXn ^-Be PF ₆ ^-, this compound is the luxuriant iron hexafluorophosphate of benzene part of β-naphthalene oxygen side group, structural formula is:

4 preparation methods of compound according to claim 1 is characterized in that:

(a) react under the Lewis acid catalysis by ferrocene, chlorobenzene and make cyclopentadiene-iron-chlorobenzene salt.Reaction conditions is: with 1 part of ferrocene, 3 parts of anhydrous AlCl ₃,, 3 parts of aluminium powders and 1 part of chlorobenzene be dissolved in 10-20 part hexanaphthene, after stirring, slowly is heated to reflux temperature, keeps reaction 8-10 hour, compound (I), add NaMXn after the hydrolysis or KMXn obtains cyclopentadiene-iron-chlorobenzene salt (II).

(b) be raw material with cyclopentadiene-iron-chlorobenzene salt (II), under alkaline condition, make the benzene ligand ferrocenium salt (III) that contains the alpha-naphthoxy side group with naphthyl alcohol generation nucleophilic substitution reaction.Reaction conditions is: 1 part of cyclopentadiene-iron-chlorobenzene salt (II) and 1.5-2 part naphthyl alcohol are dissolved in 5-10 part N, dinethylformamide, reaction is 9-11 hour under the catalysis of 1.5-2 part alkali, reaction finishes the back and adds the saturated NaMXn or the KMXn aqueous solution, gets the benzene ligand ferrocenium salt (III) of product alpha-naphthoxy side group.

(c) be raw material by cyclopentadiene-iron-chlorobenzene salt (II), under alkaline condition, make the benzene ligand ferrocenium salt (IV) that contains β-naphthalene oxygen side group with 2-Naphthol generation nucleophilic substitution reaction.Reaction conditions is: 1 part of cyclopentadiene-iron-chlorobenzene salt (II) and 1.5-2 part 2-Naphthol are dissolved in 5-10 part N, dinethylformamide, reaction is 7-9 hour under the catalysis of 1.5-2 part alkali, reaction finishes the back and adds the saturated NaMXn or the KMXn aqueous solution, gets the benzene ligand ferrocenium salt (III) of product β-naphthalene oxygen side group.

5 according to claim 1 compound in cationic photopolymerization, be used to cause epoxy compounds and vinyl ethers compound.

Images