2,3,5,6-Tetrafluorophenyl (meth) acrylates and method for production thereof

2,3,5,6-Tetrafluorophenyl (meth)acrylates represented by the general formula I: ##STR1## wherein R is H or CH.sub.3 and X is H or CN are disclosed. These compounds are obtained by the reaction of 4-cyano-substituted or unsubstituted 2,3,5,6-tetrafluorophenols with (meth)acrylic acid chloride.

BACKGROUND OF THE INVENTION 
Field of the Invention 
This invention relates to 2,3,5,6-tetrafluorophenyl (meth)acrylates and to 
a method for the production thereof. 
SUMMARY OF THE INVENTION 
The objects described above are accomplished by compounds represented by 
the general formula I: 
##STR2## 
wherein R denotes hyrogen atom or methyl group and x denotes hydrogen atom 
or cyano group. 
These objects are also accomplished by a method for the production of 
compounds represented by the general formula I, which comprises causing 
(meth)acrylic acid chlorides to react with 2,3,5,6-tetrafluorophenols 
represented by the general formula II: 
##STR3## 
wherein M denotes hydrogen atom or an alkali metal atom and X has the same 
meaning as described above. 
EXPLANATION OF PREFERRED EMBODIMENT 
the 2,3,5,6-tetrafluorophenyl (meth)acrylates, which are the compound of 
this invention represented by the general formula I, are produced by the 
reaction of 2,3,5,6-tetrafluorophenols represented by the general formula 
II with acrylic acid chloride or methacrylic acid chloride. 
For example, 2,3,5,6-tetrafluorophenyl acrylate is obtained by the reaction 
of 2,3,5,6-tetrafluorophenol or an alkali metal salt thereof with acrylic 
acid chloride, 2,3,5,6-tetrafluorophenyl methacrylate by the reaction of 
2,3,5,6-tetrafluorophenol or an alkali metal salt thereof with methacrylic 
acid chloride, 4-cyano-2,3,5,6-tetrafluorophenyl acrylate by the reaction 
of 4-cyano-2,3,5,6-tetrafluorophenol or an alkali metal salt thereof with 
acrylic acid chloride, and 4-cyano-2,3,5,6-tetrafluorophenyl methacrylate 
by the reaction of 4-cyano-2,3,5,6-tetrafluorophenol or an alkali metal 
salt thereof with methacrylic acid chloride. The term "alkali metal salt" 
as used in this specification embraces lithium salts, sodium salts, 
potassium salts, for example. Among other alkali metal salts, sodium 
salts, etc. are used preferably herein. 
The amount of (meth)acrylic acid chloride to be used in the reaction per 
mol of 2,3,5,6-tetrafluorophenols is in the range of 1.0 to 2.0 mols, 
preferably 1.05 to 1.6 mols. The aforementioned reaction is generally 
carried out in an organic solvent. Typical exmaples of the organic solvent 
usable therefor include methanol, ethanol, isopropanol, butanols, benzene, 
toluene, xylenes, carbon tetrachloride, perchloroethylene, etc. In this 
case, the concentration of the 2,3,5,6-tetrafluorophenols in the organic 
solvent is generally in the range of 2 to 30% by weight, preferably 3 to 
20% by weight. The reaction system is desired to have a hydrogen chloride 
trapping agent contained therein. Typical examples of the hydrogen 
chloride trapping agent include lithium hydroxide, sodium hydroxide, 
potassium hydroxide, magnesium carbonate, triethylamine, pyridine, 
molecular sieve, etc. The amount of this hydrogen chloride trapping agent 
so contained in the reaction system is desired to exceed the theoretical 
amount enough to react all the hydrogen chloride by-produced in the 
reaction. 
The reaction temperature is in the range of -20.degree. to +120.degree. C., 
preferably -5.degree. to +90.degree. C. The reaction time is in the range 
of 0.5 to 100 hours, preferably 1 to 70 hours. 
The 2,3,5,6-tetrafluorophenyl (meth)acrylates of this invention represented 
by the general formula I excel in the polymerizing property and, 
theerefore, are usable as raw materials for homopolymers or copolymers. 
They can be converted into various useful fluorine-containing 
(meth)acrylate polymers. These fluorine-containing (meth)acrylate polymers 
possess special functions dissimilar to the functions of the ordinary 
(meth)acrylate polymers containing no fluorine. These (meth)acrylate 
polymers, excelling in resistance to heat, resistance to light, and flame 
retardance, find utility in applications to plastics, coating materials, 
and adhesive agents. They are also usable as monomers for the production 
of electron beam resists, optical fiber sheaths, and organic 
photosensitive binders. 
Now, the method for the production of novel substances of the present 
invention will be described specifically below with reference to working 
examples. The analyses obtained of the novel substances so produced for 
the determination of their chemical structures are shown at the same time.

EXAMPLE 1 
Synthesis of 4-cyano-2,3,5,6-tetrafluorophenol 
A three-neck flask was charged with 250 g (1.295 mols) of 
pentafluorobenzonitrile, 171 g (3.05 mols) of potassium hydroxide and 500 
ml of 2-methyl-2-propanol as a solvent. In an atmosphere of nitrogen gas, 
the contents of the flask were held as stirred at 70.degree. C. for 20 
hours for reaction. Then, the reaction mixture was evaporated to dryness 
to expel 2-methyl-2-propanol. The residue of the flask was dissolved in 
250 ml of water. 
The resultant aqueous solution was adjusted to pH 2 by dropwise addition 
thereof of 6N sulfuric acid. It was added to 500 ml of ether to effect 
extraction of the organic substance. This extraction was repeated twice. 
The ether layer was dried with magnesium sulfate and then evaporated to 
drynes to expel ether. The residual crystals were recrystallized from 
benzene to obtain 4-cyano-2,3,5,6-tetrafluorophenol (yeild 81.3 mol % 
based on pentafluorobenzonitrile). 
m.p. 128.degree.-129.degree. C. 
.sup.19 F NMR (solvent: acetone-d.sub.6, external standard substance: 
trifluoroacetic acid) 
.delta.=61.4 ppm (doublet-multiplet, 2F) 
.delta.=84.7 ppm (doublet-multiplet, 2F) 
EXAMPLE 2 
In 200 ml of carbon tetrachloride, 19.1 g (0.100 mol) of 
4-cyano-2,3,5,6-tetrafluorophenol and 13.0 g (0.125 mol) of methacrylic 
acid chloride were dissolved. To the resultant solution was added 20 g of 
molecular sieve 3 .ANG. in diameter. The resultant mixture was refluxed as 
agitated for 48 hours. The reaction mixture so produced was cooled and 
then filtered to separate the molecular sieve. The filtrate was dried with 
magnesium sulfate and then evaporated to dryness with a rotary evaporator. 
Consequently, there was obtained 21.7 g of 
4-cyano-2,3,5,6-tetrafluorophenyl methacrylate (yield 83.8% based on 
4-cyano-2,3,5,6-tetrafluorophenol, purity 96.5%). 
The analyses obtained of this novel substance for the determination of its 
chemical structure are shown below. 
4-Cyano-2,3,5,6-tetrafluorophenyl methacrylate recrystallized with benzene 
Melting point 87.degree.-88.degree. C. 
Elementary analyses 
______________________________________ 
C (%) H (%) F (%) N (%) 
______________________________________ 
Calculated 50.97 1.93 29.34 5.41 
Found 50.8 1.98 29.1 5.44 
______________________________________ 
.sup.1 H NMR (solvent: CCl.sub.4, internal standard substance: TMS) 
______________________________________ 
CH.sub.3 .delta. = 2.1 ppm (Singlet, 3H) 
.delta. = 5.9 ppm (Singlet, 1H) 
CH.sub.2 
.delta. = 6.4 ppm (Singlet, 1H) 
______________________________________ 
.sup.19 F NMR (solvent: acetone-d.sub.6,external standard substance: 
trifluoroacetic acid) 
.delta.=58.8 ppm (doublet-doublet, .sup.J AB, A'B'.apprxeq.21 Hz, .sup.J 
AB', A'B.apprxeq.10 Hz, 2F) 
.delta.=75.3 ppm (doublet-doublet, .sup.J BA, B'A'.apprxeq.21 Hz, .sup.J 
BA', B'A.apprxeq.10 Hz, 2F) 
Mass analysis spectrum EI m/e=259 (M.sup.+) 
Infrared absorption spectrum (KBr) 2250 cm.sup.-1 (.sup..nu. C.tbd.N); 
1760 cm.sup.-1 (.sup..nu. C=O); 
1650 cm.sup.-1 (.sup..nu. C=C); 
1500 cm.sup.-1 (.sup..nu. F--benzene ring C=C). 
EXAMPLE 3 
In 50 ml of methanol having 0.94 g (0.0236 mol) of sodium hydroide 
dissolved therein, 3.0 g (0.0157 mol) of 4-cyano-2,3,5,6-tetrafluorophenol 
was dissolved. The resultant solution was kept with ice at 0.degree. C. To 
the cooled solution, 1.80 g (0.0173 mol) of methacrylic acid chloride as 
slowly added dropwise. After completion of this dropwise addition, the 
resultant mixture was stirred at the same temperature for two hours. It 
was then mixed with 50 ml of pure water and adjusted to pH 10 by addition 
of an aqueous 20% sodium hydroide solution. As the result, white crystals 
occurred. The white crystals were filtered, washed with cold water, and 
then dried to obtain 1.35 g of 4-cyano-2,3,5,6-tetrafluorophenyl 
methacrylate (purity 98% and yield 32 mol % based on 
4-cyano-2,3,5,6-tetrafluorophenol). The analyses obtained of this novel 
substance for the determination of its chemical structure were the same as 
those of Example 2. 
EXAMPLE 4 
In 30 ml of benzene, 3.0 g (0.0157 mol) of 
4-cyano-2,3,5,6-tetrafluorophenol and 1.80 g (0.0173 mol) of methacrylic 
acid chloride were dissolved. The resultant solution, and 1.73 g (0.0173 
mol) of calcium carbonate added thereto as a hydrogen chloride trapping 
agent were stirred under reflux for 32 hours. The resultant reaction 
mixture was cooled off and filtered to separate calcium carbonate. The 
filtrate was dried with magnesium sulfate and then evaporated with a 
rotary evaporator. Consequently, there was obtained 2.6 g of 
4-cyano-2,3,5,6-tetrafluorophenyl methacrylate (yeild 63.9% and purity 
95.4%). The analyses obtained of the novel substance for the determination 
of its chemical structure were the same as those of Example 2. 
EXAMPLE 5 
In 200 ml of carbon tetrachloride, 19.1 g (0.100 mol) of 4-cyano-2,3, 
5,6-tetrafluorophenol and 11.3 g (0.125 mol) of acrylic acid chloride were 
dissolved. To the resultant solution, 20 g of molecular sieve 3 .ANG. in 
diameter was added. The mixture was stirred under reflux for 38 hours. The 
resultant reaction mixture was cooled off and filtered to separate the 
molecular sieve. The filtrate was dried with magnesium sulfate and 
evaporated to dryness with a rotary evaporator. Consequently, there was 
obtained 15.2 g of 4-cyano-2,3,5,6-tetrafluorophenyl acrylate (yield 62.0% 
based on 4-cyano-2,3,5,6-tetrafluorophenol, purity 96.4%) having a melting 
point below determined. 
The analyses obtained of this novel substance for the determination of its 
chemical structure are shown below. 
Boiling point 62.degree. C. (2 mmHg) 
Melting point 21.degree.-23.degree. C. 
Elementary analyses 
______________________________________ 
C (%) H (%) F (%) N (%) 
______________________________________ 
Calculated 48.98 1.22 31.02 5.71 
Found 48.9 1.25 30.8 5.77 
______________________________________ 
.sup.1 H NMR (solvent: CCl.sub.4, internal standard substance: TMS) 
.delta.=5.9-7.0 ppm (multiplet, 3H) 
.sup.19 F NMR (solvent: acetone-d.sub.6,external standard substance: 
trifluoroacetic acid) 
.delta.=58.7 ppm (broad doublet, J=21 Hz, 2F) 
.delta.=75.2 ppm (broad doublet, J=21 Hz, 2 F) 
Mass analysis spectrum EI m/e=245 (M.sup.+) 
Infrared absorption spectrum (neat) 2250 cm.sup.-1 (.sup..nu. C.tbd.N) 1770 
cm.sup.-1 (.sup..nu. C=O) 1630 cm.sup.-1 (.sup..nu. C=C) 1500 cm.sup.-1 
(.sup..nu. F--benzene ring C=C) 
EXAMPLE 6 
In 30 ml of benzene, 3.82 g (0.020 mol) of 
4-cyano-2,3,5,6-tetrafluorophenol and 2.26 g (0.025 mol) of calcium 
carbonate added thereto as a hydrogen chloride trapping agent were stirred 
under reflux for 40 hours. The resultant reaction mixture was cooled off 
and filtered to separate calcium carbonate. The filtrate was dried with 
magnesium sulfate and then evaporated to dryness with a rotary evaporator. 
Consequently, there was obtained 2.8 g of 4-cyano-2,3, 
5,6-tetrafluorophenyl acrylate (yield 57.1%, purity 95.8%). The analyses 
obtained of the novel substance for the determination of its chemical 
structure were the same as those of Example 5. 
EXAMPLE 7 
In 200 ml of methanol having 4.32 g (0.108 mols) of sodium hydroxide 
dissolved therein, 12 g (0.0723 mol) of 2,3,5,6-tetrafluorophenol was 
dissolved. The resultant solution was kept at 0.degree. C. with ice. To 
the cooled solution, 8.32 g (0.0796 mol) of methacrylic acid chloride was 
slowly added dropwise. After completion of the dropwise addition, the 
mixture was stirred at the same temperature for 1.5 hours. The mixture was 
combined with 160 ml of pure water and adjusted to pH 10 by addition of an 
aqueous 20% sodium hydroxide solution. Consequently, the reaction mixture 
separated into two layers. Of the two layers, the oil layer was separated, 
washed again with pure water, dried with anhydrous sodium sulfate, and 
then rectified with a precision fractionator to recover 12.1 g of 
2,3,5,6-tetrafluorophenyl methacrylate, as a fraction boiling at 
56.degree. to 57.degree. C./3.5 mmHg, (yield 71.5 mol % based on 
2,3,5,6-tetrafluorophenol). 
The analyses obtained of the novel substance for the determination of its 
chemical structure are shown below. 
Boiling point 56.degree.-57.degree. C. (3.5 mmHg) 
Elementary analyses 
______________________________________ 
C (%) H (%) F (%) 
______________________________________ 
Calculated 51.28 2.59 32.45 
Found 51.3 2.56 32.3 
______________________________________ 
.sup.1 H NMR (solvent: CCl.sub.4, internal standard substance: TMS) 
.delta.=2.08 ppm (singlet, 3H) 
.delta.=5.80 ppm (singlet, 1H) 
.delta.=6.35 ppm (singlet, 1H) 
.delta.=6.95 ppm (quintet, .sup.J HF=9 Hz, 1H) 
.sup.19 F NMR (solvent: acetone--d.sub.6,external standard substance: 
trifluoroacetic acid) 
.delta.=64.4 ppm (broad singlet, 2F) 
.delta.=78.6 ppm (broad singlet, 2F) 
Mass analysis spectrum EI m/e=234 (M.sup.+) 
Infrared absorption spectrum (neat) 1760 cm.sup.-1 (.sup..nu. C=O); 1640 
cm.sup.-1 (.sup..delta. C=C); 1490, 1530 cm.sup.-1 (.sup..nu. F--benzene 
ring C=C). 
EXAMPLE 8 
In 200 ml of carbon tetrachloride, 16.6 g (0.100 mol) of 
2,3,5,6-tetrafluorophenol and 13.0 g (0.125 mol) of methacrylic acid 
chloride were dissolved. To the resultant solution was added 20 g of 
molecular sieve 3 .ANG. in diameter. The resultant mixture was stirred 
under reflux for 63 hours. The resultant mixture was cooled off and 
filtered to separate the molecular sieve. The filtrate was dried with 
magnesium sulfate and then rectified with a precision fractionator to 
recover 19.8 g of 2,3,5,6-tetrafluorophenyl methacrylate, as a fraction 
boiling at 56.degree. to 57.degree. C. (3.5 mmHg) (yield 84.6%, purity 
98.5%). 
The analyses obtained of the novel substance for the determination of its 
chemical structure were the same as those of Example 7. 
EXAMPLE 9 
In 40 ml of benzene, 4.1 g (0.025 mol) of 2,3,5,6-tetrafluorophenol and 3.9 
g (0.0375 mol) of methacrylic acid chloride were dissolved. The resultant 
solution and 3.75 g (0.0375 mol) of calcium carbonate added thereto as a 
hydrogen chloride trapping agent were stirred under reflux for 46 hours. 
The reaction mixture was cooled off and filtered to separate calcium 
carbonate. The filtrate was rectified with a precision fractionator to 
recover 2.9 g of 2,3,5,6-tetrafluorophenyl methacrylate, as a fraction 
boiling at 56.degree. to 57.degree. C./3.5 mmHg. 
The analyses obtained of the novel substance for the determination of its 
chemical structure were the same asthose of Example 7. 
EXAMPLE 10 
In 200 ml of carbon tetrachloride, 16.6 g (0.100 mol) of 
2,3,5,6-tetrafluorophenol and 11.3 g (0.125 mol) of acrylic acid chloride 
were dissolved. To the resultant solution was added 20 g of molecular 
sieve 3 .ANG. in diameter. The resultant mixture was stirred under reflux 
for 60 hours. The reaction mixture was cooled off and filtered to separate 
the molecular sieve. The filtrate was dried with magnesium sulfate and 
then rectified with a precision fractionator to recover 14.3 g of 
2,3,5,6-tetrafluorophenyl acrylate, as a fraction boiling at 46.degree. to 
47.degree. C. (3.5 mmHg) (yield 65.0%, purity 98.8%) 
The analyses obtained of the novel substance for the determination of its 
chemical structure are shown below. 
Boiling point 46.degree.-47.degree. C. (3.5 mmHg) 
Elementary analyses 
______________________________________ 
C (%) H (%) F (%) 
______________________________________ 
Calculated 49.11 1.84 34.53 
Found 49.1 1.86 34.4 
______________________________________ 
.sup.1 H NMR (solvent: CCl.sub.4, internal standard substance: TMS) 
.delta.=5.8-6.7 ppm (multiplet, 3H) 
.delta.=6.95 ppm (quintet, J.sub.HF =9 Hz, 1H) 
.sup.19 F NMR (solvent: acetone--d.sub.6,external standard substance: 
trifluoroacetic acid) 
.delta.=64.3 ppm (multiplet, 2F) 
.delta.=78.5 ppm (multiplet, 2F) 
Mass analysis spectrum 
EI m/e=220 (M.sup.+) 
Infrared absorption spectrum (neat) 1770 cm.sup.-1 (.sup..nu. C=O); 1640 
cm.sup.-1 (.sup..nu. C=C); 1490, 1530 cm.sup.-1 (.sup..nu. F--benzene ring 
C=C). 
EXAMPLE 11 
In 200 ml of methanol having 4.32 g (0.108 mol) of sodium hydroxide 
dissolved therein, 12 g (0.0723 mol) of 2,3,5,6-tetrafluorophenol was 
dissolved. The solution was kept at 0.degree. C. with ice. To the cooled 
solution, 7.2 g (0.0796 mol) of acrylic acid chloride was gradually added 
dropwise. After completion of the dropwise addition, the mixture was 
stirred at the same temperature for 1.5 hours. It was combined with 160 ml 
of pure water and adjusted to pH 10 by addition of an aqueous 20% sodium 
hydroxide solution. Consequently, the reaction mixture separated into two 
layers. Of the two layers, the oil layer was separated, washed again with 
pure water, dried with anhydrous sodium sulfate, and rectified with a 
precision fractionator. Consequently, there was recovered 9.8 g of 
2,3,5,6-tetrafluorophenyl acrylate, as a fraction boiling at 46.degree. to 
47.degree. C./3.5 mmHg (yield 61.6 mol % based on 
2,3,5,6-tetrafluorophenol). 
The analyses obtained of the novel substance for the determination of its 
chemical structure were the same as those of Example 10.