Process for the manufacturing of triaryl-organo borates

Abstract

The invention relates to a process for the preparation of triaryl-organo borates from boronic ester and the use of these substances in photo initiator systems, photopolymer compositions comprising such photo initiator systems, a holographic medium comprising said photopolymer composition and the respective hologram.

Claims

1. Process for the production of triaryl-organo borates of the formula 1/m A.sup.m+[R.sup.1BR.sub.3.sup.3].sup.− (IX) obtainable or obtained by reacting a boronic ester of formula B(OR.sup.2).sub.3 (I) with an organolithium- or Grignard-reagent of formula R.sup.1-E (II) in a solvent or solvent mixture S1, adding a previously formed organometallic reagent of the formula R.sup.3-M-X (V) in a solvent or solvent mixture S2, further adding a salt of the formula 1/m A.sup.m+ Y.sup.− (VIII) and isolating the precipitated triaryl-alkyl borate product of formula 1/m A.sup.m+[R.sup.1BR.sub.3.sup.3].sup.− (IX), wherein the triaryl-alkyl borate of 1/m A.sup.m+[R.sup.1BR.sub.3.sup.3].sup.− (IX) comprises less than 10.000 ppm of tetra aryl borate A.sup.m+[BR.sub.4.sup.3].sup.−, in which A stands for a substituted organic cation with the charge m on the basis of nitrogen, phosphorus, oxygen, sulfur and/or iodine, B stands for boron E stands for lithium or magnesium-monohalide, M stands for a metal selected from magnesium, calcium, aluminum, tin, zinc or cadmium, X stands for chlorine, bromine or iodine, Y stands for halide, alkoxide, or sulfide, R.sup.1 stands for a C.sub.1- to C.sub.22-alkyl-, C.sub.3- to C.sub.22-alkenyl-, C.sub.3- to C.sub.22-alkynyl-, C.sub.5- to C.sub.7-cycloalkyl- or C.sub.7- to C.sub.15-aralkyl-residue, which can be optionally substituted by oxygen or nitrogen or halogen, R.sup.2 stands for an optionally branched C.sub.1- to C.sub.22-alkyl-residue or an optionally alkyl-substituted C.sub.3- to C.sub.7-cycloalkyl-residue or an optionally aryl- or heteroaryl substituted C.sub.2- to C.sub.22-alkyl-residue or R.sup.2 may form a 2-8-membered bicyclic ring optionally substituted by alkyl residues and/or by oxygen atoms or R.sup.2 may form a 4-14-membered tricyclic ring an optionally substituted by alkyl residues and/or by oxygen atoms, R.sup.3 stands for a C.sub.6- to C.sub.14-aryl residue optionally substituted by at least one residue selected from halogen, C.sub.1-to C.sub.4-alkyl, trifluoromethyl, C.sub.1- to C.sub.4-alkoxy, trifluoromethoxy, phenyl and/or phenoxy, m stands for 1, 2 or 3, S1 and S2 independently from one another stand for an aprotic organic solvent or a mixture of aprotic organic solvents.

2. The process according to claim 1 comprising the steps of i) reacting boronic ester of formula B(OR.sup.2).sub.3 (I) in a solvent or solvent mixture S1 at a temperature or temperature range T1 with an organolithium- or Grignard-reagent of formula R.sup.1-E (II) to yield the salt of formula [R.sup.1B(OR.sup.2).sub.3].sup.−E.sup.+ (III), ii) reacting an organic halogen compound of formula R.sup.3-X (IV) in a solvent or solvent mixture S2 at a temperature or temperature range T2 with a metal M to yield an organometallic reagent of formula R.sup.3-M-X (V), iii) reacting the compounds (III) and (V) in a combined solvent or solvent mixture S1 and S2 at a temperature or temperature range T3 to yield the salts of formula [R.sup.1BR.sub.3.sup.3].sup.−E.sup.+ (VI) and of formula R.sup.2O-M-X (VII), iv) adding the salt of formula 1/m A.sup.m+ Y.sup.− (VIII) and water and v) isolating the precipitated product of formula 1/m A.sup.m+[R.sup.1BR.sub.3.sup.3].sup.− (IX) whereby T1 stands for a temperature of −110° C. to −50° C., T2 stands for a temperature of −20° C. to 100° C., and T3 stands for a temperature of 0° C. to 100° C.

3. Process according to claim 1, characterized in that R.sup.1 stands for an C.sub.2- to C.sub.18-alkyl-, C.sub.3- to C.sub.18-alkenyl-, C.sub.3- to C.sub.18-alkynyl-, C.sub.5- to C.sub.6-cycloalkyl- or C.sub.7- to C.sub.13-aralkyl residue optionally substituted by oxygen and/or halogen.

4. Process according to claim 1, characterized in that R.sup.2 stands for a branched C.sub.2- to C.sub.18-alkyl-residue or R.sup.2 forms a 2-6-membered bicyclic ring optionally substituted by alkyl residues and/or by oxygen atoms or R.sup.2 may form a 4-10-membered tricyclic ring optionally substituted by alkyl residues and/or by oxygen atoms.

5. Process according to claim 1, characterized in that R.sup.3 stands for a C.sub.6- to C.sub.10-aryl residue that may be optionally substituted by at least one of the residues selected from halogen, C.sub.1-to C.sub.4-alkyl, trifluoromethyl, C.sub.1- to C.sub.4-alkoxy, trifluormethoxy, phenyl and/or phenoxy.

6. Process according to claim 1, characterized in that S1 and S2 independently from one another stand for alkanes, alkenes, benzene and aromatics with aliphatic and/or aromatic substituents, carboxylic acid esters, ethers or mixtures thereof.

7. Process according to claim 1, characterized in that M stands for magnesium, calcium or aluminum.

Description

Synthesis of Tetrabutyl Ammonium Tris(3-Chloro-4-Methyl-Phenyl)Hexylborate

Example 1

(1) 1. Synthesis of Lithium Triisopropyl (Hexyl) Borate (Step a) 67.5 L dry THF was charged into the reactor and (4.125 kg) triisopropyl borate was added and degassed with slow stream of nitrogen gas for 15 min. The reactor was cooled to −78±2° C. and 7.5 kg n-hexyllithium (2.3 M) was transferred slowly into the reactor under stirring at this temperature. This reaction was continued for two hours under stirring at −78±2° C. After this the reaction mass was allowed to gradually reach temperature of 8±2° C.

(2) 2. Grignard Reaction (Step b) 60 L dry THF was charged into the reactor and 1.8 kg magnesium along with 60 g of iodine were added. The reactor was heated to 48±2° C. and (15 kg) 4-bromo-2-chlorotoluene along with 30 L dry THF was charged to the dropping funnel. Both the solutions from reactor and dropping funnel were degassed with slow stream of nitrogen gas for 15 min respectively. The degassed solution of 4-bromo-2-chlorotoluene from the dropping funnel was charged slowly in to reactor under stirring. A maximum amount of 4.0 L of the solution of 4-bromo-2-chlorotoluene was added before a temperature increases indicated the start of the organometallic reaction. After completion of addition, the reactor was further heated to 65±2° C. (or reflux temperature of THF) and the reaction mixture is maintained at that temperature for 3 h under stirring. Then, the reaction mixture was gradually cooled to 13±2° C. Steps a & b were carried out simultaneously but in separate reactors since neither of the intermediates are stable to storage

(3) 3. Synthesis of Tetrabutyl Ammonium Tris(3-Chloro-4-Methyl-Phenyl)Hexylborate (Steps c & d) The solution of step (a) was slowly added to the solution of step (b) at 13±2° C. under constant cooling and stirring. After completion of charging, the reactor temperature was slowly brought to room temperature and stirring was continued for next 4 h (step c). The reaction was then quenched with a solution of 4.8 kg tetrabutyl ammonium bromide in 30 L water at 27±2° C. and stirring continued for additional 30 min. 90 L of ethyl acetate was added into the reaction mass and the aqueous and organic phases were separated. The aqueous phase was discarded and the organic phase was extracted with water thrice (3*90 L). The organic phase was then concentrated to get a slurry. 150 L methanol were added to the slurry and it was heated to reflux temperature (65-70° C.) for 1-2 h and then the hot methanol solution was filtered. The solution was then cooled to 8±2° C. for 10-12 h and filtered to get the recrystallized product. The product was washed with 5-10 L methanol and dried at 60±2° C. in vaccuo until the desired LOD values (<0.1%) was achieved. The product obtained was a white solid with output of 6.3 kg, yield 50% of theory, purity ˜95% and APHA 50

Example 2

(4) 1. Synthesis of Lithium Triisopropyl (Hexyl) Borate (Step a) 67.5 L dry THF was charged into the reactor and (4.125 kg) triisopropyl borate was added and degassed with slow stream of nitrogen gas for 15 min. The reactor was cooled to −78±2° C. and 7.5 kg n-hexyllithium (2.3 M) was transferred slowly in to the reactor under stirring. This reaction was continued for two hours at 78±2° C. After this the reaction mass was allowed to gradually reach temperature of 8±2° C.

(5) 2. Grignard Reaction (Step b) 60 L dry THF was charged into the reactor and 1.8 kg magnesium along with 60 g of iodine added. The reactor was heated to 48±2° C. and (15 kg) 4-bromo-2-chlorotoluene along with 30 L dry THF was charged to the dropping funnel. Both the solutions from reactor and dropping funnel were degassed with slow stream of nitrogen gas for 15 min respectively. The degassed solution of 4-bromo-2-chlorotoluene from the dropping funnel was charged slowly into the reactor under stirring. A maximum amount of 4.0 L of the solution of 4-bromo-2-chlorotoluene was added before a temperature increases indicated the start of the organometallic reaction. After completion of addition, the reactor was further heated to 65±2° C. (or reflux temperature of THF) and the reaction mixture is maintained at that temperature for 3 h. Then, the reaction mixture was gradually cooled to 13±2° C. Steps a & b were carried out simultaneously but in separate reactors since neither of the intermediates are stable to storage

(6) 3. Synthesis of Tetrabutyl Ammonium Tris(3-Chloro-4-Methyl-Phenyl)hexylborate (Steps c & d) The solution of step (a) was slowly added to the solution of step (b) at 13±2° C. under constant cooling and stirring. After completion of charging, the reactor temperature was slowly brought to room temperature and stirring was continued for next 4 h (step c). The reaction was then quenched with a solution of 4.8 kg tetrabutyl ammonium bromide in 30 L water at 27±2° C. and stirring continued for additional 30 min. 90 L of ethyl acetate was added in to the reaction mass and the aqueous and organic phases were separated. The aqueous phase was discarded and the organic phase was extracted with water thrice (3*90 L). The organic phase was then concentrated to get a slurry. 150 L methanol were added to the slurry, and it was heated to reflux temperature (65-70° C.) for 1-2 h and then gradually cooled over the period of 6 h to 25±2° C. The reaction mass was cooled to 10±1° C. over a period of 2 h and the recrystallized product was filtered. The product was washed with 5-10 L methanol. The recrystallization process was performed two times and product was dried at 60±2° C. in vaccuo until the desired LOD values (<0.1%) was achieved. The product obtained was a white solid with output of 5.6 kg, yield 45% of theory, purity ˜97% and APHA 30.

Example 3

(7) 1. Synthesis of Lithium Triisopropyl (Hexyl) Borate (Step a) 180 L dry THF was charged into the reactor and (11 kg) triisopropyl borate was added and degassed with slow stream of nitrogen gas for 15 min. The reactor was cooled to −78±2° C. and 20 kg n-hexyllithium (2.3 M) was transferred slowly into the reactor under stirring. This reaction was continued for two hours at −78° C. After this the reaction mass was allowed to gradually reach temperature of 8±2° C.

(8) 2. Grignard Reaction (Step b) 160 L dry THF was charged into the reactor and 4.8 kg magnesium along with 160 g of iodine added. The reactor was heated to 48±2° C. and (40 kg) 4-bromo-2-chlorotoluene along with 80 L dry THF was charged to the dropping funnel. Both the solutions from reactor and dropping funnel were degassed with slow stream of nitrogen gas for 15 min respectively. The degassed solution of 4-bromo-2-chlorotoluene from the dropping funnel was charged slowly into the reactor under stirring. A maximum amount of 4.0 L of the solution of 4-bromo-2-chlorotoluene was added before a temperature increases indicated the start of the organometallic reaction. After completion of addition, the reactor was further heated to 65±2° C. (or reflux temperature of THF) and the reaction mixture is maintained at that temperature for 3 h. Then, the reaction mixture was gradually cooled to 13±2° C. Steps a & b were carried out simultaneously but in separate reactors since neither of the intermediates are stable to storage

(9) 3. Synthesis of Tetrabutyl Ammonium Tris(3-Chloro-4-Methyl-Phenyl)Hexylborate (Steps c & d) The solution of step a was slowly added to the solution of step b at 13±2° C. under constant stirring. After completion of charging, the reactor temperature was slowly brought to room temperature and stirring was continued for next 4 h (step c). The reaction was then quenched with a solution of 12.8 kg tetrabutyl ammonium bromide in 80 L water at 27±2° C. and stirring continued for additional 30 min. 240 L of ethyl acetate was added in to the reaction mass and the aqueous and organic phases were separated. The aqueous phase was discarded and the organic phase was extracted with water thrice (3*240 L). The organic phase was then concentrated to get a slurry. 400 L methanol were added to the slurry and it was heated to reflux temperature (65-70° C.) for 1-2 h and then gradually cooled over the period of 6 h to 25±2° C. The reaction mixture was then cooled to 10±1° C. over a period of 2 h and the recrystallized product was filtered. The product was washed with 10-15 L methanol. The resulting crude product was dissolved in 52 L ethyl acetate and filtered through 0.2 μm cartridge filter. Ethyl acetate was evaporated and product was precipitated out from the concentrated mass in 60 L methanol. Precipitated mass was cooled to 10° C. (for 30 min) and the product was isolated by filtration. The product was dried at 80±2° C. in vaccuo until the desired LOD values (<0.1%) was achieved. The product obtained was a white solid with output of 18.46 kg, yield 55% of theory, purity ˜96% and APHA 40

(10) TABLE-US-00001 TABLE 1 Example 1 Example 2 Example 3 Isolated Yield [%] 50 45 55 Purity by HPLC method 1 [%] 95 97 96 Colour [APHA] 50 30 40

(11) As presented in table 1, the examples 1, 2, and 3 can be produced according the inventive process containing step a)-d) in excellent yields and purities.

Preparation of Holographic Media

Example Medium 1 (M1)

(12) 3.38 g of polyol component 1 were mixed with 2.00 g of acrylate 1, 2.00 g of acrylate 2, 1.50 g of additive 1, 0.10 g of tetrabutyl ammonium tris(3-chloro-4-methyl-phenyl)hexylborate (example 1), 0.018 g of Dye 1, 0.09 g of example 1 and 0.35 g of ethyl acetate at 40° C. to obtain a clear solution. The solution was then cooled down to 30° C., 0.65 g of Desmodur® N3900 (commercial product from Covestro AG, Leverkusen, Germany, hexane diisocyanate-based polyisocyanate, portion on iminooxadiazinedione at least 30%, NCO content: 23.5%) was added before renewed mixing. Finally, 0.01 g of Fomrez UL 28 (urethanization catalyst, commercial product of Momentive Performance Chemicals, Wilton, Conn., USA) was added and again briefly mixed in. The mixed photopolymer formulation was applied on 36 μm thick polyethylene terephthalate film. The coated film was dried for 5.8 minutes at 80° C. and finally covered with a 40 μm polyethylene film. The achieved photopolymer layer thickness was around 14 μm.

(13) The media M2 and M3 were prepared analogously using 0.10 g tetrabutyl ammonium tris(3-chloro-4-methyl-phenyl)hexylborate from example 2 and example 3.

(14) TABLE-US-00002 TABLE 2 Example Medium Example Δn M1 1 0.040 M2 2 0.040 M3 3 0.039

(15) As presented in table 2, holographic media with the examples 1, 2, and 3 produced according the inventive process containing step a)-d) provide holographic media with high index contrast.