TITLE OF INVENTION:
METHOD FOR PRODUCING CYCLOBUTANE TETRACARBOXYLIC ACID
DERIVATIVE
5
TECHNICAL FIELD
The present invention relates to a method for producing an alicyclic tetracarboxylic
acid anhydride which can be a raw material monomer for e.g. a polyamic acid or a
polyimide for an optical material.
10
BACKGROUND ART
In general, polyimide resins are widely used as electronic materials such as
protective materials or insulating materials, in liquid crystal display elements or
semiconductors, by virtue of their characteristics such as high mechanical strength, heat
15 resistance, insulating properties and solvent resistance. Further, they are recently
expected to be used as optical communication materials such as optical waveguide
materials.
In recent years, developments in this field are remarkable, and along with such
developments, materials to be used are also required to have increasingly higher
20 properties. That is, they are expected not only to be excellent in heat resistance and
solvent resistance but also to have various properties depending upon the particular
applications.
However, particularly in the case of a wholly aromatic polyimide resin, it has a
deep amber color, which brings about a problem in its use as an optical material where
25 high transparency is required.
On the other hand, as one method to realize transparency, it is known that a
polyimide precursor is formed by a polycondensation reaction of an alicyclic
tetracarboxylic acid anhydride and an aromatic diamine, and the precursor is imidated
to produce a polyimide, whereby it is possible to obtain a polyimide having high
30 transparency with relatively little coloration (Patent Documents 1 and 2).
Heretofore, in the synthesis of an alkylcyclobutanoic acid dianhydride, it is
possible to obtain a mixture of 1,3-dimethylcyclobutane-1,2,3,4-tetracarboxylic acid2
1,2:3,4-dianhydride (abbreviated as 1,3-DM-CBDA) and 1,2-dimethylcyclobutane-
1,2,3,4-tetracarboxylic acid-1,2:3,4-dianhydride (abbreviated as 1,2-DM-CBDA) by
photodimerization reaction of citraconic anhydride (abbreviated as MMA), as
represented by the following scheme. (See Patent Document 3.)
Meanwhile, when 1,3-DMCBDA and 1,2-DMCBDA are compared, it is known 5 n that
the former 1,3-DMCBDA having a highly symmetric structure is more useful since it is
possible to produce a polyimide having a higher molecular weight than the latter 1,2-
DMCBDA.
Although Patent Document 3 discloses that it is possible to obtain a mixture of 1,3-
10 DMCBDA and 1,2-DMCBDA, it fails to disclose that the former 1,3-DMCBDA, which is
an isomer having a higher utility, is selectively produced in a high yield.
PRIOR ART DOCUMENTS
PATENT DOCUMENTS
15 Patent Document 1: JP-B-2-24294
Patent Document 2: JP-A-58-208322
Patent Document 3: JP-A-4-106127
DISCLOSURE OF INVENTION
20 TECHNICAL PROBLEM
The object of the present invention is to provide a method for producing a 1,3-
dialkyl-1,2,3,4-cyclobutane tetracarboxylic acid-1,2:3,4-dianhydride (hereinafter, also
referred to as 1,3-DACBDA), which is an isomer having a higher symmetric structure, at
a high photoreaction efficiency and in a high yield, by subjecting the maleic anhydride
25 compound of the formula (1) to a photodimerization reaction.
SOLUTION TO PROBLEM
hν
O O
O
O O
MeMe O
O O
O
O O
Me O
Me
1,3-DM-CBDA 1,2-DM-CBDA
O
O
O
Me
MMA
3
The present inventors have conducted extensive studies to solve the above
problems and as a result, have found that it is possible to produce a 1,3-DACBDA
derivative, which is an isomer having a higher symmetric structure, in an improved
selectivity and in a high yield, when a specific solvent is used.
The present invention has been made based on the above novel discovery 5 and
provides the following.
1. A method for producing a 1,2,3,4-cyclobutane tetracarboxylic acid-1,2:3,4-
dianhydride derivative represented by the formula (2), which comprises subjecting a
maleic anhydride compound represented by the following formula (1) to a
10 photodimerization reaction, in a solvent of a carbonic acid diester.
wherein R is a C1-20 alkyl group.
2. The method according to the above 1, wherein R is a C1-4 alkyl group.
3. The method according to Claim 1 or 2, wherein the carbonic acid diester is a C1-4
alkyl diester of carbonic acid.
15 4. The method according to any one of the above 1 to 3, wherein the carbonic acid
diester is dimethyl carbonate or diethyl carbonate.
5. The method according to the above 4, wherein the solvent contains, as a sub
solvent other than the carbonic acid diester, methyl formate, ethyl formate, methyl
acetate, ethyl acetate, n-propyl acetate, i-propyl acetate, methyl propionate, ethyl
20 propionate, n-propyl propionate, i-propyl propionate, ethylene glycol diformate or
ethylene glycol diacetate.
6. The method according to any one of the above 1 to 5, wherein the amount of all
the solvents to be used for the reaction is from 3 to 300 times by mass to the maleic
anhydride compound.
25 7. The method according to any one of the above 1 to 5, wherein the amount of all
solvents to be used for the reaction is from 3 to 10 times by mass to the maleic
4
anhydride compound.
8. The method according to any one of the above 1 to 7, wherein a sensitizer is
further used.
9. The method according to the above 8, wherein the sensitizer is benzophenone,
benzaldehyde, benzophenone substituted with an electron-withdrawing gr5 oup,
acetophenone substituted with an electron-withdrawing group, benzaldehyde
substituted with an electron-withdrawing group or anthraquinone.
10. The method according to the above 9, wherein the electron-withdrawing group is
at least one member selected from the group consisting of a fluoro group, a chloro
10 group, a bromo group, an iodo group, a nitro group, a cyano group and a trifluoromethyl
group.
11. The method according to the above 9 or 10, wherein the number of electronwithdrawing
groups is from 1 to 5.
12. The method according to any one of the above 8 to 11, wherein the sensitizer is
15 used in a proportion of from 0.1 to 20 mol% to the maleic anhydride compound.
13. The method according to any one of the above 1 to 12, wherein the reaction
temperature is from 0 to 20 C.
ADVANTAGEOUS EFFECTS OF INVENTION
20 According to the production method of the present invention, when a 1,2,3,4-
cyclobutane tetracarboxylic acid-1,2:3,4-dianhydride derivative is produced by
subjecting the maleic anhydride compound to a photodimerization reaction, it is possible
to improve the selectivity of a 1,3-dialkyl cyclobutane-1,2,3,4-tetracarboxylic acid-
1,2:3,4-dianhydride.
25
DESCRIPTION OF EMBODIMENTS
Now, the present invention will be described in further detail.
The method for producing a 1,2,3,4-cyclobutanetetracarboxylic acid-1,2:3,4-
dianhydride derivative represented by the formula (2), by subjecting a maleic anhydride
30 compound represented by the formula (1) to a photodimerization reaction, is
represented by the following reaction scheme.
5
wherein R is a C1-20, more preferably a C1-12, particularly preferably a C1-6 alkyl group.
The C1-20 alkyl group may be a linear or branched saturated alkyl group, or a linear
or branched unsaturated alkyl group.
As a specific example, a saturated alkyl group such as methyl, ethyl, n-propyl, 5 ipropyl,
n-butyl, i-butyl, s-butyl, t-butyl, n-pentyl, 1-methyl-n-butyl, 2-methyl-n-butyl, 3-
methyl-n-butyl, 1,1-dimethyl-n-propyl, n-hexyl, 1-methyl-n-pentyl, 2-methyl-n-pentyl,
1,1,-dimethyl-n-butyl, 1-ethyl-n-butyl, 1,1,2-trimethyl-n-propyl, n-heptyl, n-octyl, n-nonyl,
n-decyl, n-dodecyl or n-eicosyl, or an unsaturated alkyl group such as 1-methylvinyl, 2-
10 allyl, 1-ethylvinyl, 2-methylallyl, 2-butenyl, 2-methyl-2-butenyl, 3-methyl-2-butenyl, 3-
methyl-3-butenyl, 2-hexenyl, 4-methyl-3-pentenyl, 4-methyl-4-pentenyl, 2,3-dimethyl-2-
butenyl, 1-ethyl-2-pentenyl, 3-dodecenyl, propargyl, 3-butynyl, 3-methyl-2-propynyl or 9-
decynyl may be mentioned.
Here, n represents normal, i represents iso, s represents secondary, and t
15 represents tertiary, respectively.
The maleic anhydride compound represented by the formula (1) may, for example,
be citraconic anhydride, 2-ethyl maleic anhydride, 2-isopropyl maleic anhydride, 2-nbutyl
maleic anhydride, 2-t-butyl maleic anhydride, 2-n-pentyl maleic anhydride, 2-nhexyl
maleic anhydride, 2-n-heptyl maleic anhydride, 2-n-octyl maleic anhydride, 2-n20
nonyl maleic anhydride, 2-n-decyl maleic anhydride, 2-n-dodecyl maleic anhydride, 2-neicosyl
maleic anhydride, 2-(1-methyl vinyl) maleic anhydride, 2-(2-allyl) maleic
anhydride, 2-(1-ethyl vinyl) maleic anhydride, 2-(2-methyl allyl) maleic anhydride, 2-(2-
butenyl) maleic anhydride, 2-(2-hexenyl) maleic anhydride, 2-(1-ethyl-2-pentenyl) maleic
anhydride, 2-(3-dodecenyl) maleic anhydride, 2-propargyl maleic anhydride, 2-(3-
25 butynyl) maleic anhydride, 2-(3-methyl-2-propynyl) maleic anhydride or 2-(9-decynyl)
maleic anhydride.
Among them, e.g. citraconic anhydride, 2-ethyl maleic anhydride, 2-isopropyl
6
maleic anhydride, 2-n-butyl maleic anhydride, 2-t-butyl maleic anhydride, 2-n-pentyl
maleic anhydride, 2-n-hexyl maleic anhydride, 2-n-heptyl maleic anhydride, 2-n-octyl
maleic anhydride, 2-n-nonyl maleic anhydride, 2-n-decyl maleic anhydride or 2-ndodecyl
maleic anhydride is preferred, and citraconic anhydride, 2-ethyl maleic
anhydride, 2-isopropyl maleic anhydride, 2-n-butyl maleic anhydride, 2-t-butyl malei5 c
anhydride, 2-n-pentyl maleic anhydride or 2-n-hexyl maleic anhydride is more preferred,
in view of high photoreaction efficiency.
In this photoreaction, a reaction solvent plays an important role, and the reaction
solvent is a carbonic acid diester. As the carbonic acid diester, preferably a C1-4, more
10 preferably a C1-3, particularly preferably a C1-2 alkyl diester of carbonic acid, is suitable.
In particular, dimethyl carbonate or diethyl carbonate is preferred, and dimethyl
carbonate is particularly preferred.
In the present invention, the carbonic acid diester may be used in combination
with a sub solvent other than the carbonic acid diester. Such a solvent may, for
15 example, be methyl formate, ethyl formate, n-propyl formate, i-propyl formate, n-butyl
formate, i-butyl formate, methyl acetate, ethyl acetate, n-propyl acetate, i-propyl acetate,
n-butyl acetate, i-butyl acetate, methyl propionate, ethyl propionate, n-propyl propionate,
i-propyl propionate, n-butyl propionate, i-butyl propionate, ethylene glycol diformate,
ethylene glycol diacetate or ethylene glycol dipropionate.
20 Among them, more preferred solvent may, for example, be methyl formate, ethyl
formate, methyl acetate, ethyl acetate, n-propyl acetate, i-propyl acetate, methyl
propionate, ethyl propionate, n-propyl propionate, i-propyl propionate, ethylene glycol
diformate or ethylene glycol diacetate, and most preferred solvent is ethyl acetate.
As an excellent feature of the method for producing a DACBDA derivative by using
25 a carbonic acid diester as a solvent, it is possible to suppress a reverse reaction from
the DACBDA compound to the maleic anhydride compound or a side reaction such as
production of oligomer, since the solubility of a CBDA compound produced is low
despite that the solubility of the maleic anhydride compound as a raw material is high
and thereby to precipitate it as a crystal.
30 The amount of the solvent to be used is from 3 to 300 times by mass, more
preferably from 3 to 250 times by mass to the maleic anhydride compound.
Further, in order to increase the reaction rate or the yield of the product, the
7
amount of the reaction solvent to be used is preferably low. For example, when the
concentration of the maleic anhydride compound becomes high, the reaction rate
increases, and the yield of the product obtainable becomes large. Accordingly, in order
to increase the reaction rate or the yield of the product, the amount of the solvent to be
used is preferably from 3 to 10 times by mass to the maleic anhydride compound5 .
In this photoreaction, a wavelength of light is from 200 to 400 nm, more preferably
from 250 to 350 nm, particularly preferably from 280 to 330 nm. As a light source, a
low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury
lamp, an ultrahigh-pressure mercury lamp, a xenon lamp, an electrodeless lamp or a
10 light-emitting diode, etc. is preferred since it is possible to obtain a CBDA derivative
compound in a particularly high yield. Among them, a high-pressure mercury lamp, an
ultrahigh-pressure mercury lamp or a light-emitting diode is preferred.
Further, with respect to a photochemical reaction apparatus, if a light sourcecooling
pipe is changed from lime glass to Pyrex (registered trademark) glass, a colored
15 polymer is less attached to the light source-cooling pipe and impurities are less
produced, and therefore it is possible to improve the yield of a CBDA derivative
compound, such being preferred.
If the reaction temperature becomes high, a polymer tends to be produced as a
by-product, and if the reaction temperature becomes low, the solubility of the maleic
20 anhydride compound tends to be low, whereby the production efficiency will be
deteriorated. Therefore, the reaction temperature is preferably from -20 to 80°C, more
preferably from -10 to 50°C. In particular, when the reaction temperature is from 0 to
20°C, the production of a by-product is significantly suppressed, and therefore it is
possible to obtain a CBDA derivative compound in a high selectivity and a high yield.
25 The reaction time may vary depending upon e.g. the amount of a maleic
anhydride compound to be charged, the type of a light source or the irradiation dose,
but it is possible to carry out the reaction until the proportion of an unreacted maleic
anhydride compound reaches preferably a range of from 0 to 40%, more preferably a
range of from 0 to 10%.
30 The reaction time is usually from 1 to 200 hours, preferably from 1 to 100 hours,
more preferably from 1 to 60 hours under the conditions where a high-pressure mercury
lamp or a light-emitting diode is used as a light source, dimethyl carbonate or ethyl
8
acetate is used as a reaction solvent, 4,4’-difluorobenzophenone or 4,4’-
dichlorobenzophenone is used as a sensitizer, and a reaction temperature range of from
0 to 20 C.
Further, the conversion rate may easily be obtained by analyzing a reaction fluid
by e.g. gas chromatography5 .
As the reaction time becomes long, the conversion rate of a maleic anhydride
compound increases and the precipitation amount of a CBDA derivative compound
thereby increases, and as a result, the CBDA derivative compound produced tends to
attach to an exterior wall (a reaction fluid side) of a light source-cooling pipe, whereby
10 crystal coloration or a decrease of light efficiency (unit power × yield per hour)
accompanied by decomposition reaction tends to be observed. Therefore, it is
practically undesirable to take a long time in one batch for increasing the conversion
rate of the maleic anhydride compound since the production efficiency decreases.
Further, the reaction may be carried out by either a batch-type or a flow-type, but a
15 batch-type is preferably used.
Further, the reaction pressure may be either atmospheric pressure or elevated
pressure, but is preferably atmospheric pressure.
Further, the production method of the present invention may be carried out by
adding a sensitizer. The sensitizer may, for example, be benzophenone,
20 benzaldehyde, anthraquinone, benzophenone substituted with an electron-withdrawing
group, acetophenone substituted with an electron-withdrawing group or benzaldehyde
substituted with an electron-withdrawing group.
The electron-withdrawing group may be at least one member selected from the
group consisting of a fluoro group, a chloro group, a bromo group, an iodine group, a
25 nitro group, a cyano group and a trifluoromethyl group, preferably a fluoro group, a
chloro group, a bromo group, a cyano group or a trifluoromethyl group, particularly
preferably a fluoro group or a chloro group.
The number of the electron-withdrawing group is from 1 to 10, preferably from 1 to
5, and it is preferably from 1 to 3 in view of the effect of the present invention.
30 The substitution position of the electron-withdrawing group may be ortho position,
meta position or para position, preferably ortho position or para position, to the carbonyl
group.
9
When the number of the electron-withdrawing group is two or more, the electronwithdrawing
groups may be the same or different. Further, it may be a case where two
electron-withdrawing groups substituted at the ortho position together form carbonyl
group (that is anthraquinone).
As a specific example of benzophenone or benzophenone substituted 5 ed with an
electron-withdrawing group, benzophenone, 2-fluorobenzophenone, 3-
fluorobenzophenone, 4-fluorobenzophenone, 2-chlorobenzophenone, 3-
chlorobenzophenone, 4-chlorobenzophenone, 2-cyanobenzophenone, 3-
cyanobenzophenone, 4-cyanobenzophenone, 2-nitrobenzophenone, 3-
10 nitrobenzophenone, 4-nitrobenzophenone, 2,4’-dichlorobenzophenone, 4,4’-
difluorobenzophenone, 4,4’-dichlorobenzophenone, 4,4’-dibromobenzophenone, 3,3’-
bis(trifluoromethyl)benzophenone, 3,4’-dinitrobenzophenone, 3,3’-dinitrobenzophenone,
4,4’-dinitrobenzophenone, 2-chloro-5-nitrobenzophenone, 1,3-bis(4-
fluorobenzoyl)benzene, 1,3-bis(4-chlorobenzoyl)benzene, 2,6-dibenzoylbenzonitrile,
15 1,3-dibenzoyl-4,6-dinitrobenzene or anthraquinone may be mentioned.
Among them, 4,4’-difluorobenzophenone or 4,4’-dichlorobenzophenone is
preferred.
As a specific example of acetophenone or acetophenone substituted with an
electron-withdrawing group, acetophenone, 2’-fluoroacetophenone, 3’-
20 fluoroacetophenone, 4’-fluoroacetophenone, 2’-chloroacetophenone, 3’-
chloroacetophenone, 4’-chloroacetophenone, 2’-cyanoacetophenone, 3’-
cyanoacetophenone, 4’-cyanoacetophenone, 2’-nitroacetophenone, 3’-
nitroacetophenone, 4’-nitroacetophenone, 2’,4’-difluoroacetophenone, 3’,4’-
difluoroacetophenone, 2’,4’-dichloroacetophenone, 3’,4’-dichloroacetophenone, 4’-
25 chloro-3’-nitroacetophenone, 4’-bromo-3’-nitroacetophenone or 4’-fluoro-3’-
nitroacetophenone may, for example, be mentioned.
Among them, 4’-fluoroacetophenone, 4’-chloroacetophenone, 2’,4’-
difluoroacetophenone, 3’,4’-difluoroacetophenone, 2’,4’-dichloroacetophenone or 3’,4’-
dichloroacetophenone is preferred.
30 Benzaldehyde or benzaldehyde substituted with an electron-withdrawing group
may, for example, be benzaldehyde, 2-fluorobenzaldehyde, 3-fluorobenzaldehyde, 4-
fluorobenzaldehyde, 2-chlorobenzaldehyde, 3-chlorobenzaldehyde, 4-
10
chlorobenzaldehyde, 2-cyanobenzaldehyde, 3-cyanobenzaldehyde, 4-
cyanobenzaldehyde, 2-nitrobenzaldehyde, 3-nitrobenzaldehyde, 4-nitrobenzaldehyde,
2,4-difluorobenzaldehyde, 3,4-difluorobenzaldehyde, 2,4-dichlorobenzaldehyde, 3,4-
dichlorobenzaldehyde, 2-chloro-5-nitrobenzaldehyde, 4-chloro-2-nitrobenzaldehyde, 4-
chloro-3-nitrobenzaldehyde, 5-chloro-2-nitrobenzaldehyde, 2-fluoro-5 5-
nitrobenzaldehyde, 4-fluoro-3-nitrobenzaldehyde or 5-fluoro-2-nitrobenzaldehyde.
Among them, 4-fluorobenzaldehyde, 4-chlorobenzaldehyde, 2,4-
difluorobenzaldehyde, 3,4-difluorobenzaldehyde, 2,4-dichlorobenzaldehyde or 3,4-
dichlorobenzaldehyde is preferred.
10 The amount of the sensitizer to be used is not particularly limited so long as it is
possible to accelerate a photoreaction rate, but it is preferably from 0.1 to 20 mol%,
more preferably from 0.1 to 5 mol% to the maleic anhydride compound.
As the sensitizer, the above benzophenone derivative, acetophenone derivative or
benzaldehyde derivative may be used alone or two or more of them may be used in
15 combination, but the sensitizer is preferably used alone in view of easiness of treatment
after the reaction.
The desired compound may be obtainable by carrying out photoreaction, filtrating
a precipitate in a reaction fluid, washing a collected product with an organic solvent,
folowed by drying under reduced pressure.
20 The amount of the organic solvent to be used for washing the collected product, is
not limited so long as it is possible to transfer a precipitate remained in a reactor to a
filter, but if the amount of the organic solvent is large, the desired compound tends to be
transferred to a filtrate, whereby the recovery rate decreases. Therefore, the amount
of the organic solvent to be used for washing the collected product, is preferably from
25 0.5 to 10 times by mass, more preferably from 1 to 2 times by mass, to the maleic
anhydride compound used in the reaction.
The organic solvent to be used for washing the collected product is not particularly
limited, but it is undesirable to use a solvent having high solubility of the product, since
the desired compound tends to be transferred to a filtrate and the recovery rate thereby
30 decreases. Therefore, the organic solvent to be used for washing the collected
product may, for example, be methyl formate, ethyl formate, n-propyl formate, i-propyl
formate, n-butyl formate, i-butyl formate, methyl acetate, ethyl acetate, n-propyl acetate,
11
i-propyl acetate, n-butyl acetate, i-butyl acetate, methyl propionate, ethyl propionate, npropyl
propionate, i-propyl propionate, n-butyl propionate, i-butyl propionate, ethylene
glycol diformate, ethylene glycol diacetate, ethylene glycol dipropionate, dimethyl
carbonate or diethyl carbonate, or a solvent which does not solve a product and is not
reactive with the product, such as toluene, hexane, heptane, acetonitrile, 5 , acetone,
chloroform or acetic anhydride, or a mixed solvent thereof, as a reaction solvent to be
used for photodimerization reaction. Among them, ethyl acetate, dimethyl carbonate or
acetic anhydride is preferred, and ethyl acetate or dimethyl carbonate is more preferred.
10 EXAMPLES
Now, the present invention will specifically be described with reference to
Examples, but it should be understood that the present invention is by no means
restricted thereto.
Further, analytical methods employed in Examples are as follows.
15
Apparatus: GC-2010 Plus (manufactured by SHIMADZU Corporation),
Column: DB-1 (manufactured by GL Sciences Inc.,) 0.25 mm ×30 m, film
thickness 0.25 um,
Carrier gas: He, detector: FID, sample injection amount: 1 um, inlet port
20 temperature: 160°C, detector temperature: 220°C, column temperature: 70°C (20 min)-
40°C/min-220°C (15 min), split ratio: 1:50, internal standard substance: butyl lactate.
<1H NMR analytical conditions>
Apparatus: Fourier transform superconducting NMR spectrometer (FT-NMR)
INOVA-400 (manufactured by Varian) 400 MHz,
25 Solvent: DMSO-d6, internal standard substance: tetramethylsilane (TMS).

Apparatus: DSC1 (manufactured by Mettler-Toredo International Inc.),
Temperature: 35°C-5°C/min-400°C, Pan: Au (closed).
COMPARATIVE EXAMPLE 1
12
In a nitrogen atmosphere, into a 30 mL Pyrex (registered trademark) glass test
tube, 0.10 g (0.89 mmol) of a citraconic anhydride (CA), 20 g (270 mmol, 200 times by
weight to the citraconic anhydride (CA)) of methyl acetate were charged, and dissolved
with stirring by a magnetic stirrer. Then, the resultant was irradiated with a 100 W
high-pressure mercury lamp for 4 hours with stirring at a temperature of from 5 to 10°5 °C.
After the irradiation, the reaction fluid was quantitatively analyzed by gas
chromatography, and as a result the remaining ratio of the citraconic anhydride (CA)
was 29.9%. Then, 2 g of the reaction fluid in a reaction vessel was taken out, and a
solvent was distilled off under a pressure of from 70 to 80 Torr by an evaporator. A
10 crude product obtained was analyzed by 1H NMR and confirmed to be a mixture
containing 1,3-DM-CBDA and 1,2-DM-CBDA (1,3-DM-CBDA:1,2-DM-CBDA=42.6:57.4).
1 H NMR ( DMSO-d6, δ ppm ) ( 1,3-DM-CBDA ): 1.38 ( s, 6H ), 3.89 ( s, 2H ).
1 H NMR ( DMSO-d6, δ ppm ) ( 1,2-DM-CBDA ): 1.37 ( s, 6H ), 3.72 ( s, 2H ).
EXAMPLE 1
15 In a nitrogen atmosphere, into a 30 mL Pyrex (registered trademark) glass test
tube, 0.10 g (0.89 mmol) of a citraconic anhydride (CA), 20 g (222 mmol, 200 times by
weight to the citraconic anhydride (CA)) of dimethyl carbonate were charged, and
dissolved with stirring by a magnetic stirrer. Then, the resultant was irradiated with a
100 W high-pressure mercury lamp for 4 hours with stirring at a temperature of from 15
20 to 20°C. After the irradiation, the reaction fluid was quantitatively analyzed by gas
chromatography, and as a result the remaining ratio of the citraconic anhydride (CA)
was 26.2%. Then, 2 g of the reaction fluid in a reaction vessel was taken out, and a
solvent was distilled off under a pressure of from 70 to 80 Torr by an evaporator. A
crude product obtained was analyzed by 1H NMR and confirmed to be a mixture
O
O
O
h
1,3-DM-CBDA
O O
O O
O O
CA 1,2-DM-CBDA
O O
O O
O O
AcOMe
O
O
O
h
1,3-DM-CBDA
O O
O O
O O
CA 1,2-DM-CBDA
O O
O O
O O
Me2CO3
13
containing 1,3-DM-CBDA and 1,2-DM-CBDA (1,3-DM-CBDA:1,2-DM-CBDA=48.3:51.7).
COMPARATIVE EXAMPLES 2 to 28 and EXAMPLE 2
A series of operations was carried out in the same manner as in Comparative
Example 1 except that each solvent was added in a proportion of 200 times by weight to
a citraconic anhydride (CA). Further, the remaining ratio of a citraconic anhydride (5 CA)
and the production ratio (1,3-DM-CBDA:1,2-DM-CBDA) of 1,3-DM-CBDA to 1,2-DMCBDA
were calculated.
The solvent, temperature, amount of by-product, and the result are shown in the
following Table. Further, the remaining ratio of the citraconic anhydride in a reaction
10 fluid obtained herein, and the production ratio of 1,3-DM-CBDA to 1,2-DM-CBDA were
calculated, and shown in Table together with the results obtained in Comparative
Examples 1 and Example 1. Here, the reaction rate in Table was calculated from the
number of moles of the citraconic acid used and the remaining ratio of the citraconic
acid at the time when the reaction was carried out for 4 hours.
15
14
TABLE 1
Solvent
Temperature
production ratio
(1H NMR)
Remaining ratio
of citraconic
anhydride
(GC quantity)
Production
amount of
by-product
1,3-DMCBDA
1,2- DMCBDA
[°C] [mol%] [mol%] [%]
Ex. 1 Dimethyl carbonate 15-20 48.3 51.7 26.2 Very trace
amount
Ex. 2 Diethyl carbonate 5-10 49.0 51.0 7.9 Very trace
amount
Comp.
Ex. 1 Methyl acetate 5-10 42.6 57.4 29.9 Very trace
amount
Comp.
Ex. 2 Ethyl acetate 5-10 41.8 58.2 19.1 Very trace
amount
Comp.
Ex. 3 Propyl acetate 5-10 43.1 56.9 23.9 Trace
amount
Comp.
Ex. 4 Isopropyl acetate 5-10 43.7 56.3 13.2 Trace
amount
Comp.
Ex. 5 Butyl acetate 5-10 44.1 55.9 33.6 Trace
amount
Comp.
Ex. 6 Tert-butyl acetate 15-20 41.2 58.8 16.1 Small
amount
Comp.
Ex. 7 Methyl propionate 5-10 43.9 56.1 30.5 Very trace
amount
Comp.
Ex. 8 Methyl butyrate 5-10 42.6 57.4 36.7 Trace
amount
Comp.
Ex. 9 γ-butyrolactone 5-10 28.3 71.7 * Very trace
amount
Comp.
Ex. 10 Acetic acid 15-20 39.8 60.2 39.1 Very trace
amount
Comp.
Ex. 11 Dimethyl malonate 5-10 40.3 59.7 * Very trace
amount
Comp.
Ex. 12
Ethylene glycol
diacetate 5-10 42.9 57.1 * Very trace
amount
Comp.
Ex. 13 Acetic anhydride 5-10 37.3 62.7 43.2 Trace
amount
Comp.
Ex. 14 Propylene carbonate 5-10 19.0 81.0 * Trace
amount
Comp.
Ex. 15 Acetone 5-10 33.4 66.6 21.0 Trace
amount
Comp.
Ex. 16 Methyl ethyl ketone 5-10 33.6 66.4 19.4 Trace
amount
Comp.
Ex. 17 Chloroform 5-10 56.2 43.8 35.9 Large
amount
Comp.
Ex. 18 Dichloromethane 5-10 39.7 60.3 51.0 Very trace
amount
Comp.
Ex. 19 1,2-Dichloroethane 5-10 38.0 62.0 18.8 Trace
amount
Comp.
Ex. 20 n-heptane 5-10 43.7 56.3 5.1 Small
amount
Comp.
Ex. 21 Cyclohexane 15-20 41.7 58.3 2.4 Small
amount
Comp.
Ex. 22 Acetonitrile 5-10 40.2 59.8 67.8 Very trace
amount
Comp.
Ex. 23 Dimethylformamide 5-10 0 0 61.8 Large
amount
Comp.
Ex. 24 Dimethylacetamide 5-10 0 0 66.6 Large
amount
Comp.
Ex. 25 Tetrahydrofuran 5-10 0 0 6.9 Large
amount
Comp.
Ex. 26 Dimethoxyethane 5-10 0 0 3.4 Large
amount
Comp.
Ex. 27 Pyridine 5-10 0 0 87.4 Trace
amount
Comp.
Ex. 28 Toluene 5-10 0 0 93.1 Trace
amount
* Analysis was impossible since peaks of a solvent and a raw material were overlapped.
15
EXAMPLE 3
O
O
O
h
1,3-DM-CBDA
O O
O O
O O
CA 1,2-DM-CBDA
O O
O O
O O
Me2CO3
In a nitrogen atmosphere, into a 300 mL Pyrex (registered trademark) glass five5
necked flask, 35.0 g (312 mmol) of a citraconic anhydride (CA) and 152 g (1,682 mmol,
4.33 times by weight to the citraconic anhydride (CA)) of dimethyl carbonate were
charged and dissolved with stirring by a magnetic stirrer. Then, the resultant was
irradiated with a 100 W high-pressure mercury lamp for 48 hours with stirring at a
temperature of from 10 to 15°C. A reaction fluid was analyzed by gas chromatography,
10 and the remaining ratio of the raw material was confirmed to be 23.7%. Thereafter, a
white crystal precipitated was obtained by filtration at a temperature of from 10 to 15°C,
and this crystal was washed twice with 43.8 g (497 mmol, 1.25 times by weight to the
citraconic anhydride (CA)) of ethyl acetate. Then, this crystal was dried under reduced
pressure to obtain 8.1 g (yield: 23.1%) of a white crystal. This crystal was analyzed by
15 1H NMR and confirmed to be a mixture (1,3-DM-CBDA:1,2-DM-CBDA = 90.3:9.7)
containing 1,3-DM-CBDA and 1,2-DM-CBDA. Further, a crystal, a filtrate and a
washing liquid obtained were quantitatively analyzed respectively by 1H NMR analysis
and gas chromatography. Mass balance to the charged amount was 88.9%.
EXAMPLE 4
20 In a nitrogen atmosphere, into a 30 mL Pyrex (registered trademark) glass test
tube, 0.10 g (0.89 mmol) of a citraconic anhydride (CA), 0.020 g (0.11 mmol, 20 mass%
to the citraconic anhydride (CA)) of benzophenone (BP) and 20 g (222 mmol, 200 times
by mass to the citraconic anhydride (CA)) of dimethyl carbonate were charged, and
dissolved with stirring by a magnetic stirrer. Then, the resultant was irradiated with a
25 100 W high-pressure mercury lamp for 4 hours with stirring at a temperature of from 10
O
O
O h
BP
1,3-DM-CBDA
O O
O O
O O
CA 1,2-DM-CBDA
O O
O O
O O
Me2CO3
16
to 15°C. After the irradiation, a reaction fluid was quantitatively analyzed by gas
chromatography, and as a result the remaining ratio of the citraconic anhydride (CA)
was 3.9%. Further, 2 g of the reaction fluid in a reaction vessel was taken out, and a
solvent was distilled off under a pressure of from 70 to 80 Torr by an evaporator. A
crude product obtained was analyzed by 1H NMR and confirmed to be a mixtur5 e
containing 1,3-DM-CBDA and 1,2-DM-CBDA (1,3-DM-CBDA:1,2-DM-CBDA=48.3:51.7).
EXAMPLE 5
A series of operations was carried out in the same manner as in Example 4 except
that 4,4’-dichlorobenzophenone (DCIBP) was added as a sensitizer, and the remaining
10 ratio of the citraconic anhydride (CA) and the production ratio (1,3-DM-CBDA:1,2-DMCBDA)
of 1,3-DM-CBDA to 1,2-DM-CBDA, were calculated in the same manner as in
Comparative Example 1.
The solvent, temperature, sensitizer, amount of by-product, and the result are
shown in the following Table. Further, the remaining ratio of the citraconic anhydride in
15 a reaction fluid obtained herein, and the production ratio of 1,3-DM-CBDA to 1,2-DMCBDA
were calculated, and shown in Table together with the results obtained in
Example 4. Here, the reaction rate in Table was calculated from the number of moles
of the citraconic acid used and the remaining ratio of the citraconic acid at the time
when the reaction was carried out for 4 hours.
20 TABLE 2
solvent
Temperature
Sensitizer
production ratio
(1H NMR)
Remaining ratio
of citraconic
anhydride
(GC quantity)
1,3-DMCBDA
1,2- DMCBDA
[°C] [mol%] [mol%] [%]
Ex. 4 Dimethyl
carbonate 10-15 BP 48.3 51.7 3.9
Ex. 5 Dimethyl
carbonate 10-15 DClBP 48.3 51.7 0
REFERENCE EXAMPLE 1
1,3-DM-CBDA
O O
O O
O O
1,2-DM-CBDA
O O
O O
O O
Ac2O
1,3-DM-CBDA
O O
O O
O O
reflux
17
In a nitrogen stream, into a 200 mL four-necked flask, 18.3 g of a mixture (1,3-DMCBDA:
1,2-DM-CBDA = 85:15) containing 1,3-DM-CBDA and 1,2-DM-CBDA, obtained in
the same manner as in Example 3, and 92 g of acetic anhydride were charged and
suspended at 25°C with stirring by a magnetic stirrer, followed by heat reflux (130°C) for
4 hours, and then cooled so that the internal temperature would be 25°C or lower5 ,
followed by stirring for one hour at a temperature of 25°C or lower. Then, a white
crystal precipitated was filtrated, and a crystal obtained was washed twice with 18 g of
ethyl acetate. Thereafter, a white crystal precipitated was dried under reduced
pressure to obtain 14.4 g (yield: 92%) of a high purity 1,3-DM-CBDA. The crystal was
10 analyzed by 1H NMR, whereby the ratio of 1,3-DM-CBDA to 1,2-DM-CBDA was
confirmed to be 1,3-DM-CBDA:1,2-DM-CBDA = 99.5:0.5.
1 H NMR ( DMSO-d6, δ ppm ) ( 1,3-DM-CBDA ): 1.38 ( s, 6H ), 3.89 ( s, 2H ).
1 H NMR ( DMSO-d6, δ ppm ) ( 1,2-DM-CBDA ): 1.37 ( s, 6H ), 3.72 ( s, 2H ).
mp. ( 1,3-DM-CBDA ): 316-317°C
15
INDUSTRIAL APPLICABILITY
The cyclobutane carboxylic acid derivative obtained in the present invention is a
compound useful as a raw material for e.g. a polyamic acid or a polyimide, and such a
polyimide is industrially widely useful as a resin composition used for electronic
20 materials such as protective materials or insulating materials, in liquid crystal display
elements or semiconductors.
The entire disclosure of Japanese Patent Application No. 2014-007186 filed on
January 17, 2014 including specification, claims and summary is incorporated herein by
25 reference in its entirety.
18

CLAIMS
1. A method for producing a 1,2,3,4-cyclobutane tetracarboxylic acid-1,2:3,4-
dianhydride derivative represented by the formula (2), which comprises subjecting a
maleic anhydride compound represented by the following formula (1) to a
photodimerization reaction, in a solvent of a carbonic acid diester5 .
wherein R is a C1-20 alkyl group.
2. The method according to Claim 1, wherein R is a C1-4 alkyl group.
3. The method according to Claim 1 or 2, wherein the carbonic acid diester is a C1-4
alkyl diester of carbonic acid.
10 4. The method according to any one of Claims 1 to 3, wherein the carbonic acid
diester is dimethyl carbonate or diethyl carbonate.
5. The method according to Claim 4, wherein the solvent contains, as a sub solvent
other than the carbonic acid diester, methyl formate, ethyl formate, methyl acetate, ethyl
acetate, n-propyl acetate, i-propyl acetate, methyl propionate, ethyl propionate, n-propyl
15 propionate, i-propyl propionate, ethylene glycol diformate or ethylene glycol diacetate.
6. The method according to any one of Claims 1 to 5, wherein the amount of all
solvents to be used for the reaction is from 3 to 300 times by mass to the maleic
anhydride compound.
7. The method according to any one of Claims 1 to 5, wherein the amount of all
20 solvents to be used for the reaction is from 3 to 10 times by mass to the maleic
anhydride compound.
8. The method according to any one of Claims 1 to 7, wherein a sensitizer is further
used.
9. The method according to Claim 8, wherein the sensitizer is benzophenone,
25 benzaldehyde, benzophenone substituted with an electron-withdrawing group,
acetophenone substituted with an electron-withdrawing group, benzaldehyde
substituted with an electron-withdrawing group or anthraquinone.
10. The method according to Claim 9, wherein the electron-withdrawing group is at
least one member selected from the group consisting of a fluoro group, a chloro group,
a bromo group, an iodo group, a nitro group, a cyano group and a trifluoromethyl group.
11. The method according to Claim 9 or 10, wherein the number of electronwithdrawing
groups is from 1 to 5.
12. The method according to anyone of Claims 8 to 11, wherein the sensitizer is used
in a proportion of from 0.1 to 20 mol% to the maleic anhydride compound.
13. The method according to any one of Claims 1 to 12, wherein the reaction
temperature is from 0 to 20°C.