JPH01142094A - Production of aniline derivative - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an electrochemical method for producing certain 2- and ≠-no-roanilines.

[Background of the invention] W, Lob, Berm Dt+seh, Che
m, Gel1. ), 2, 7g ri<ivt? ≠) discloses a method for producing no- and ≠-chloroaniline by passing electrical current through a segmented cell containing a platinum cathode, nitrobenzene, and concentrated hydrochloric acid in a cathode compartment. Elps (E1b++) and Silbermann, Zwet
To Electro, +4 (Z, Elektrochem
, ), 7, Jio (IRI02) also includes an electrochemical method using a segmented cell containing a copper cathode, a corresponding nitrobenzene and a mixture of hydrochloric acid and alcohol in the cathode compartment. The production of certain Hiro-chloroanilines by reduction has been disclosed.

We hereby note that when producing 2- and
It was found that the rent yield was inferior.

Current yield and current density are important factors considered when scaling up electrochemical processes to industrial production. Thus, the higher the current yield and current density at which the process can be performed, the smaller the cells it requires and the lower the capital cost of the process.

Surprisingly, we have here shown that certain 2- and - It has been found that haloanilines can be advantageously produced at high current densities.

[Structure of the Invention and Detailed Description of the Invention] Accordingly, the present invention provides a substituted aniline at the 2-position or ≠ position corresponding to an aniline substituted at the 2-position or the bromine
In the method for producing aniline from non-substituted nitrobenzene, a solution in which the nitrobenzene is dissolved in a medium consisting of an aqueous hydrohalodanic acid selected from hydrochloric acid and hydrobromic acid is added to the cathode. ) passing an electric current through a segmented electrochemical cell having a graphite cathode contained within the compartment;

Preferably, the medium contained in the cathode compartment also contains an organic solvent, otherwise preferably a phase transfer catalyst or a nonionic surfactant must be included in the cathode medium. Suitable phase transfer catalysts include trialkylammonium halides, such as dodecyltrimethylammonium bromide, and suitable nonionic surfactants include trialkylamino-N-oxide,
Examples include dimethyldodecylamino-N-oxide.

When the selected hydrohalodanic acid is hydrochloric acid,
The product of the process is chloroaniline, and when the hydrohalic acid selected is hydrobromic acid, the product of the process is bromoaniline.

The nitrobenzene may be unsubstituted or substituted. Generally, the nitrobenzene contains only seven nitro groups. Preferably the nitrobenzene is unsubstituted or has a halogen atom,
Aryl group, alkyl group, alkylaryl group, alkoxy group, haloalkyl group, haloalkoxy group, cyano group, alkanoyl group, hydroxy group, amino group, alkyl (6) Amino group, dialkylamino group, carboxy group and aminocarbonyl is substituted with at least 7 substituents selected from the group consisting of: More preferably, the nitrobenzene is substituted with 7 or co substituents selected from fluorine atoms, methoxy groups, trifluoromethyl groups and hydroxy groups. For example, the nitrobenzene can be 2-fluoronitrobenzene, ≠-fluoronitrobenzene, 2-nitroanisole, 2-nitropenzotrifluoride, 3-nitrophenol or 4-fluoro-3-nitrophenol.

In this specification, unless specified otherwise, any alkyl group preferably contains / to O carbon atoms and any aryl group is preferably a phenyl group. The rhodan atom can be, for example, a fluorine atom, a chlorine atom or a bromine atom.

It will be appreciated that the concentration of nitrobenzene in solution is not critical to the operation of the process and will depend on many factors such as temperature and whether an organic solvent is used. Conveniently, the concentration is! ;-2! ; OF
lll=, preferably 10 to 100911=.

The cathode compartment can advantageously contain some undissolved nitrobenzene, since the anilines obtained by the process of the invention are generally more soluble in the cathode medium than the corresponding nitrobenzenes.

We have found that in the method of the present invention, the /.rodan atom is generally inserted at the ≠ position preferentially over the 2-position. Therefore, when the nitrobenzene is unsubstituted at the 2 and ≠ positions, the major product will generally be ≠-no-roaniline.

The segmented electrochemical cell used in the method of the invention may be any conventional segmented electrochemical cell. It is understood that this cell must be divided by a porous material that is selectively permeable to protons.

Preferably the cell is partitioned by a cation exchange membrane, a suitable membrane being manufactured by Du Pont de Nemours.
t da Nemourts ) to [Nafion (N
AFION) Cation exchange membranes sold under the trademark J and Asahi Chemical Kant! = −(As
perfluorinated cation exchange membranes, such as those sold under the trademark FIJMION J by Hahi Chemical Company.

The electrodes in an electrochemical cell can conveniently be configured in the form of parallel flat or mesh electrodes or in the form of a bed of individual particles. The cathode is preferably an oxidan dimensional 5 stable anode (
DSA) or lead dioxide or titanium on board.

(The oxidane DSA electrode consists of titanium coated with a mixture of transition metal oxides).

filter-press cell
Particularly satisfactory results have been obtained using the following methods:

A convenient electrolyte medium for use in the anode compartment is a mixture of sulfuric acid, for example 7 to 5 moles of sulfuric acid, and an organic solvent, for example an organic solvent present in the cathode compartment.

The current efficiencies obtained by the present invention were found to be surprisingly high when compared with those obtained by methods of the type described by Lob, Elbs and Silbermann. . Furthermore, it has been found that this current doping rate is substantially unaffected by increasing current density within normal practical working ranges. In fact, in real numbers using electrochemical cells separated by cation exchange membranes,
The current yield was found to be high even at current densities of /0.000 Am-2, which are close to the practical working limit of the membrane. Generally, in the method of the present invention, 10θ~/2,0
00km, preferably j00~A, 000 Am
A range of current densities is used.

The voltages used during the process of the invention may vary during the course of electrolysis, and this variation is anticipated by those skilled in the art.

Conveniently, this voltage is between 3 and 20 delts, preferably 7
0 is in the range below root.

When using an organic solvent in the process of the invention, it must be miscible with water. Preferred organic solvents are selected from C(,2~≠) alkanols, aptane, tetrahydrofuran, acetonitrile and acetic acid. More preferably, the organic solvent is selected from ethanol, deron-/-o/l/, 7'ropan-2-ol and acetic acid. The volume percentage of organic solvent in the solution depends on the particular solvent used and the desired concentration of nitrobenzene, which generally ranges from 5 to 30.

The concentration of the hydrohalic acid used in the medium in the cathode compartment is preferably between 3 and 2 molar, more preferably 3/2 molar.
~/θ molar concentration range. When the hydrohalodic acid is hydrobromic acid, the concentration of the acid in the medium is preferably lower than the concentration used when hydrochloric acid is chosen, e.g. It can be in the range of .

The method conveniently operates between 20 and 10'θC, preferably 4
It can be carried out at temperatures ranging from 0 to C.

The haloanilines produced by the method of the invention are useful as intermediates in the production of pesticides, medicines, and dyes.
For example, H-chloro-2-fluoroaniline, as described in U.S. Pat.
Useful in the production of herbicidally active compounds.

〔Example〕

Next, the present invention will be explained in more detail with reference to the following examples. Examples/~23 illustrate the method of the present invention, while Examples 2≠~2B are comparative examples.

Example / Preparation of ≠-chloro-λ-fluoroaniline A flat graphite cathode (/!;, j cm, vertically arranged) and a glass hemisphere (diameter 3α) fitted with a sintered glass disk (diameter 3α) Volume, approximately 103), glass tube (for filling electrolyte and releasing generated gas) and -Xl, i-shaped platinum wire anode (diameter/■, length/jan
An anode compartment consisting of a 720 m1 jacketed glass beaker was prepared using a 720 m1 jacketed glass beaker.

The cell was closed with an airtight lid and fitted with a gas inlet tube (to introduce nitrogen below the catholyte surface) and a water-cooled condenser. The catholyte was stirred vigorously by a magnetic stirrer bar. AM hydrochloric acid in the cathode compartment //j
The anode compartment was filled with 3M sulfuric acid//jvol% n-Zolo/Gnol (10yn) while filling the anode compartment with %n-propertool (/00 cm3) by volume. At 70℃/, O
After passing a current of A through the cell for 5 minutes, no-fluoronitrobenzene was added (/, j, F), then an additional 3"0 min until a total of A, j of 2-fluoronitrobenzene had been added. The electrolysis was continued for another 5 hours at /, OA and 70 °C. The catholyte was removed and diluted with water to 230 cm', then the sample (2,0 cm' ) was neutralized, extracted with ether and analyzed by gas chromatography, which showed that 27 g of ≠-chloro-2-fluoroaniline were produced (current yield 3 T).

Example 2 Production of ≠-chloro-2-fluoroaniline Filter press cell (Electroc, ell
) A 1 MICROFL (/3) flow cell (*MICROFL CELL), available from A
NAPION)≠23) was installed. - a set of spacers (polytetrafluoroethylene (Poly Tet)
raFluoro Ethylene) and gaskets (*KALREZ, available from DuPont de Nemours) form the cathode and anode compartments and the /3 of the cathode and anode.
An area of cm2 was exposed. When the cell was assembled, the distance between the cathode and anode was 2. To increase turbulence and mixing, place a piece of gauze in each compartment.
Polyvinylidene fluoride (P
'olyVinyliDensFluoride),
A filament diameter of about 1 m and a mesh of about 10 cm) were placed. Both the cathode compartment and the anode compartment are each equipped with a stirring reservoir (2!; O
m3) and connected to separate electrolyte circulation loops.

Add Otsu M hydrochloric acid/20 Yodo% n-propa to the catholyte reservoir (/≠
) Nol (!00crn3) while filling the anolyte reservoir with 3M sulfuric acid/20% by volume n-Pro/('Nol(,2
j 0cm3) 'k was filled. The contents of these reservoirs are heated and passed through each electrode compartment in 3θ.
It was circulated at a rate of l/hr. When both the catholyte and anolyte reached a temperature of 70 °C, a current of /, j A was passed through the cell ( /, 000 A-m-2).

j minute diameter Ninofluoronitrobenzene (20IILl.

After that, electrolysis was continued for 7j hours at /, J-A and 70°C. The catholyte was drained, cooled, neutralized, and extracted with ether. Analysis of the ether extract by gas chromatography showed that it yielded 7.2 g of ≠-chlorounofluoroaniline (current yield 1I-f96).

The above-mentioned official seal indicates a trademark.

Example 3 ≠0I for the first production of ≠-chloro-2-fluoroaniline
by the same electrolytic cell and procedure as described in Example No., except that no fluoronitrobenzene was added and a current of 000 Am-2 was used. Performed electrolysis.

At Otsu A and 70℃ 2. 'After an hour has passed,
The catholyte was removed, neutralized and extracted with ether. Analysis of the ether extract by gas chromatography showed that 70.311 ≠-chloro-fluoro-fluoro-anilines were produced (current yield j3).

Example ≠ Preparation of t-chloro-2-fluoroaniline Electrolysis was carried out by the same cell and procedure as described in Example 3, except that a current of isA (/0,000 Am-2) was used. . The temperature inside the cell rapidly rose from the initial value of 7θ°C to ♂0°C. After 7 hours at /jA and f0°C, the catholyte was removed, neutralized, and extracted with ether.

Analysis of the ether extract by gas chromatography shows that 10. It was shown that /l/≠-chlorounofluoroaniline was produced (current yield j2%).

(/Z) Example ≠ - Preparation of chloro-2-fluoroaniline The procedure was as described in Example 3 except that 7M hydrochloric acid/20% by volume n-propanol was used as the catholyte and the operation was carried out at 2°C. Electrolysis was carried out using the same cell and procedure as described above. 3. At Otsu A and 52°C. After two hours, the catholyte was removed, cooled, neutralized, and extracted with ether.

Analysis of the ether extract by gas chromatography showed the formation of ≠-chloro-2-fluoroaniline (current yield: 3%).

Example B ≠ - Kuroru! - Manufacture of fluoroaniline thinner (reducing the volume of the cathode and anode compartments by about 2j%)
Electrolysis was carried out using the same cell as described in Example 3, except that a gasket was used that exposed only 10 crn2 of each electrode. M hydrochloric acid in the catholyte reservoir 7
．． While filling 20 volumes of n-propanol (,20
0cn1), (/7) The anolyte reservoir was filled with 3M sulfuric acid/20% by volume n-zolotsuknol. The contents of these reservoirs were circulated through each electrode compartment while being heated at a rate of 30 A”hr−1. When both the catholyte and anolyte reached a temperature of 5θ° C., a current of 1 AOA was applied. Through the cell (≠00OA-
m-2). After 5 minutes, no-fluoronitrobenzene was added (4tOg) and then heated at 40A and 50°C for 3
Electrolysis continued for hours. The catholyte was removed, cooled, neutralized, and extracted with ether. Analysis of the ether extract by gas chromatography showed the formation of Hiro-chloro-2-fluoroaniline with ≠1 (current yield j7).

Example 7 Preparation of ≠-chlorofluoroaniline 4'00
cm paste M hydrochloric acid/2θ capacity coefficient n-proper tool and 10
Electrolysis was carried out using the same cell as described in Example j, except that a 300 cm catholyte reservoir containing 0 g of 2-fluoronitrobenzene was used. Otsu A and! ;
After 7.7 hours at 2°C, the catholyte was removed and evaporated in the form of an azeodorope with water at 2°C.

To completely remove 2-fluoronitrobenzene,
An extra 730 cm' of water had to be added. Add ether (/00twr') f to the distillate,
The resulting separated ether layer was washed with dilute sodium hydroxide solution (3.3M/0cm) and then washed with 2-fluoronitrobenzene (3.3M) by drying and flashing.
3! /, purity >'ys%) n-proper tool (j j
z') solution was produced. The remaining catholyte is diluted with bicarbonate 8
) The aniline was removed by neutralization with IJum and then evaporation at 1,0° C. and 0.7 par. In order to completely remove aniline, even more! 00c
m' of water had to be added. Ether (/00 cm3) was added to the distillate and the resulting separated ether layer was diluted with hydroxide (8) IJ solution (/Ocm3).
, 3M), followed by drying and 7 lashes of the solvent to produce 3011≠-chloro-2-fluoroaniline (current yield≠l!i'chi) and Example g~/Hiro≠- Preparation of chlorofluoroaniline The electrolysis was carried out using the same cell and procedure as described in Example B, except that 7M hydrochloric acid containing 20 volumes of any of the seven organic solvents listed below was used. carried out.

a, ethanol b, methanol C, acetone d, inzolopanol e, tetrahydrofuran f, acetic acid g, acetonitrile.
cm) While filling the anolyte reservoir with 3M sulfuric acid/
20 volumes of organic solvent (23θcrn) were charged. The contents of these reservoirs were circulated through each electrode compartment at a rate of 301-hr while being heated. 1 AOA when both catholyte and anolyte reach a temperature of 50°C
A current of 100 mL was passed through the cell (HiroOOOA-m-2). After 5 minutes, 2-fluoronitrobenzene was added (≠09
) until it becomes clear that cathode passivation has occurred (a rapid rise in cell potential).
and continued electrolysis at 10°C. The catholyte was removed, cooled, neutralized, and extracted with ether.

The current yield was determined by gas chromatographic analysis of the ether extract (see Table 1).

Table/Example Organic solvent current yield (%) g
Ethanol yo≠7 Methanol jIlo Acetone
33// 2-Property tool jza/
, 2 THF j Otsu/3
Acetic acid Example/j 2-amino-! -Production of chloranisole (2/) The cathode compartment of the cell described in Example/ is filled with 7M hydrochloric acid/2θ volume thiethanol (/00 cm3), while the anode compartment is filled with 3M sulfuric acid/20 volume thiethanol (/00 cm3). 0c
m3) was filled. lj min/, OA at O℃
After passing a current through the cell, cornitroanisole was added (2.0 g), followed by additional o, si additions every 30 minutes until a total of 0.0 g was added. Electrolysis was continued for another 6 hours at the same current and temperature. The catholyte was drained, neutralized, and extracted with ether. Analysis of the ether extract by gas chromatography showed the presence of 2-amino-J--chloranisole, C, 2.21! , current density 27%).

Example/Production of 2-Amino-Y-Chlorpenzotrifluoride Example/The cathode compartment of the cell described in Example/ was filled with 7M hydrochloric acid/20 volumes of chlorine-propanol (/Ocm').
□I did. After passing a current of lj min/oA through the cell at 50 °C, add 2-nitropenzotrifluoride (/, jF), then o every 30 min until a total of oI has been added. , sg each. Electrolysis was continued for another hour at the same current and temperature. The catholyte was then drawn off, neutralized, and extracted with ether. Analysis of the ether extract by gas chromatography revealed that 2 The main products of the species were found to be formed. These products were identified as 2-amino-j-chlorobenzotrifluoride and !-aminopenzotrifluoride (ratio, 2:/) .

Example/7! -Kurorou! - The cathode compartment of the cell described in Example for the production of aminone enol was filled with M hydrochloric acid/20 volumes of cetanol (10O♂), while the anode compartment was filled with 3M sulfuric acid/20 volumes of ethanol (/Ocm). did.

After passing a current of θA through the cell at θ℃, 3-
Nitrophenol was added (/, jg), then o, sg every 30 minutes until the total soybean was added.

Electrolysis continued for 5 hours at the same current and temperature. The catholyte was diluted with water (/00 Crn3) and then extracted with ether (!; 0 cm3Xλ times). The aqueous phase was neutralized with sodium bicarbonate and the resulting precipitated pale brown solid was collected and dried ( , 2., f 17 , n, m
, r, and identified as p)-chloro-aminophenol by mass spectrometry, current yield 37 h).

Example/Do! -Chlorolu≠-Fluoroaniline Production Example/The cathode compartment of the cell described in Example is filled with M hydrochloric acid/2θ volume chetanol (10θtTn), while the anode compartment is filled with 3M
Charged with sulfuric acid/20 volumes thiethanol (70m). After passing a current of 00 jA through the cell for 75 minutes at 0°C, ≠-fluoronitrobenzene was added (/, jll),
Then o, t every 30 minutes until a total of OI has been added.
, p were added. At the same current and temperature, 5
Electrolysis continued for hours. The catholyte was removed, neutralized and extracted with ether. Analysis of the ether extract by gas chromatography showed the presence of 2-chloro-≠-fluoroaniline (/, 1
If, 9, current yield 3≠%).

In the cathode compartment of the cell described in Example/Example/20.
The anode compartment was filled with 3M sulfuric acid/20% n-propatol (10 crn) while the anode compartment was filled with % n-pro9nol (/00 cm3) by volume. 7 at 50℃
．． After passing a current of 0 A through the cell for 75 minutes, 2-fluoronitrobenzene e7711 Mt (/J11) was then added in o, sg increments every 30 minutes until a total of 0 g was added. Electrolysis continued for 441 hours at the same current and temperature. The catholyte was drained, neutralized, and extracted with ether. Analysis of the ether extract by gas chromatography showed the presence of ≠-bromunofluoroaniline (3., !i' j,
! ? , current yield≠g%).

Example 20 Preparation of j-Amino-Norchlor-≠-Fluorophenol The cathode compartment of the cell described in Example was filled with M hydrochloric acid/JD cetanol (3; cm), while (
2) Add 3M sulfuric acid/10 volumes of thiethanol (10z
3) was filled. After passing a current of /A through the cell for minutes at 60°C, 4-fluoro-3-nitrophenol (
A solution of lAoy) in ethanol Bcm3) was added. Electrolysis continued for 3 hours at the same current and temperature. The catholyte was removed, diluted with water (jθcrn3) and diluted with ether (1
00crn3). The aqueous phase was neutralized and then treated with ether (!; Ocm 5 x 3) and ethyl acetate (7
J-α3).

Dry the combined organic extracts (Mg5O4),
Then, when evaporated under vacuum, it is determined by nuclear magnetic resonance spectroscopy. -Chlorolu 1l--A black solid (2,011) identified as fluorophenol was obtained.

Example 2/ Production of ≠-chloro-2-fluoroaniline Filter press cell (Electrocell)
) AB Available from Electroce # (ELEC
A TROCELL) MP cell (CELL) was fitted with a graphite cathode (surface area/00 cm2), an oxygen DSA anode and an anode ()6) ion exchange membrane (Nafion≠23 available from DuPont de Nemours). Both the cathode compartment and the anode compartment were connected to separate electrolyte circulation loops, each consisting of a centrifugal punch and a stirring reservoir with heating mantle (ldm5). Add 7M hydrochloric acid (lAj) to the catholyte reservoir.
dm) and 2-fluoronitrobenzene (7θOg), while adding 4t,j M sulfuric acid (IA3r) to the anolyte reservoir.
dm3) was added. The contents of these reservoirs were heated to 11°C under nitrogen and then IA j dm -mtn
It was circulated through each electrode compartment at a rapid rate. A current of 4 tOA (41 KA-m-2) was passed through the cell for 3 hours.

The catholyte was removed from the reservoir and the catholyte compartment and catholyte reservoir of the cell were washed with water (/dm) before these washes were combined with the catholyte. After leaving it at room temperature overnight,
The 2-fluoronitrobenzene (lower layer) was removed and the catholyte was extracted with ether (0.3; dm3X
The combined extracts were added to the 2-fluoronitrobenzene phase (3 times) and the resulting ethereal solution was dried (Mg5O4) and evaporated to yield 2-fluoronitrobenzene (331.1).

The catholyte was adjusted to pH4 with concentrated ammonia water (,2,A dm3).
After neutralizing with L, it was extracted with dichloromethane (0.j
dm5 x 3 times). The combined ether extracts were dried (Mg5O4) and evaporated to give ≠-chloro-2-fluoroaniline (/711 selectivity≠Tati). The current yield was j2chi.

Example 22 Production of ≠-Chlorofluoroaniline (dodecyl bromide) IJ methylammonium C10 before starting electrolysis
Electrolysis was carried out by the same cell and procedure as described in Example 2/, except that 11) was also added to the catholyte reservoir. After passing a current of 4 tOA for 6.3 hours, the electrolysis was stopped and the catholyte was removed from the reservoir. The catholyte compartment and catholyte reservoir of the cell were washed with water (/dm) before the wash was combined with the catholyte. After standing overnight at room temperature, remove to 'no-fluoronitrobenzene (lower layer)'.
The catholyte was then extracted with dichloromethane (0..2
! ; dm x 3 times). The combined extracts were λ−
Addition to the fluoronitrobenzene phase and evaporation of the resulting dichloromethane solution from dry Mg5O4) yields 2-fluoronitrobenzene (336I).
was generated. The catholyte was neutralized with concentrated aqueous ammonia (2, dm3) to P)I≠ and then extracted with dichloromethane (0.23 dm3 x 3 times). The combined ether extracts were dried (Mg5o4) and evaporated to give ≠-chloro-2-fluoroaniline (/dj9, selectivity 5is).

The current yield was j≠chi.

Example 23 ≠-Chloro! - Production of fluoroaniline Jy Before starting electrolysis, dimethyldodecylamino-N-oxide (Og
) was also added to the catholyte reservoir, but the electrolysis was carried out by the same cell and procedure as described in Example 2/. l
After passing the l-OA current for 6.3 hours, the electrolysis was stopped,
The catholyte was then removed from the reservoir. Wash the cathode compartment and catholyte reservoir of the cell with water (/dm3) and then
The wash solution was combined with the catholyte. After leaving to stand overnight at room temperature (29), the no-fluoronitrobenzene (lower layer) was filtered out, and the catholyte was extracted with dichloromethane (0.2
3dm x 3 times). The combined extracts were added to the 2-fluoronitrobenzene phase and the resulting dichloromethane solution was dried (Mg5O4) and evaporated to yield no-fluoronitrobenzene (33011). Dilute the catholyte with concentrated ammonia water (2 dm') to PI (
After neutralizing to 4t, it was extracted with dichloromethane (0
．． 23'dm x 3 times). The combined ether extracts were dried (Mg5O4) and evaporated to give ≠-chloro-2-fluoroaniline (/1211.
selection rate 52%).

The current yield was 3.

Example 2 ≠ ≠ - Preparation of chloro-2-fluoroaniline A flat platinum plate cathode (/, 2.j tyn, metered vertically) and a sintered glass disk (diameter 3α) were attached. A glass hemisphere (volume, approximately 10 cm), a glass tube (to be filled with electrolyte and to release generated gas), and a platinum wire positive (3θ) pole (diameter/fi, length). The anode compartment consists of a 73 cm long wire wound into a spiral shape of about 3 m in diameter.
The mixture was prepared in a jacketed glass beaker. The cell was closed with an airtight lid and fitted with a gas inlet tube (to introduce nitrogen below the catholyte surface) and a water-cooled condenser.

The catholyte was stirred vigorously by a magnetic stirrer bar.

Concentrated hydrochloric acid (700 m) was introduced into the cathode compartment, while dilute sulfuric acid (10 volumes, 3/θ) was completely introduced into the anode compartment.

After passing a current of 0.2 A through the cell for minutes, 1,2-fluoronitrobenzene <309) was added and electrolysis continued for 77 hours at 0.2 A and room temperature. The catholyte was drained, neutralized, and extracted with ether. Analysis of the ether extract by gas chromatography showed the presence of trace amounts of ≠-chloro-2-fluoroaniline (o, o y Ii, current yield 3%).

Example No.j (Comparative Example) ≠-Production Example of Chlorofluoroaniline, 24
In the cathode compartment of the cell described under −
Charged with promatric alcohol (10 crn3). 0.0 for 75 minutes at 70°C. After passing a current of ≠A through the cell, 2-fluoronitrobenzene (to,p) was added and then electrolysis was continued for 5 hours at the same current. The catholyte was removed, neutralized and extracted with ether. Analysis of the ether extract by gas chromatography showed the presence of Hiro-chlorouno-fluoroaniline (o, ty y, current yield 9 t).

Example 2. l! ; (Comparative example)

Claims (10)

[Claims] (1) In the method for producing aniline from nitrobenzene which is not substituted at the 2- or 4-position, which corresponds to an aniline whose 2- or 4-position is substituted with a chlorine atom or a bromine atom, hydrochloric acid and passing an electric current through a segmented electrochemical cell having graphite electrodes containing in the cathode compartment a solution in which said nitrobenzene is dissolved in a medium consisting of an aqueous hydrohalic acid selected from hydrobromic acid. , the manufacturing method. (2) The manufacturing method according to claim (1), wherein the medium in the cathode compartment contains an organic solvent. (3) Nitrobenzene is not substituted, or a halogen atom, a phenyl group, a C(1-6) alkyl group,
C(1-6) alkylphenyl group, C(1-6) alkoxy group, C(1-6) haloalkyl group, C(1-6) haloalkoxy group, cyano group, C(1-6) alkanoyl group, Substituted with at least one substituent selected from a hydroxy group, an amino group, a C(1-6) alkylamino group, a C(1-6) dialkylamino group, a carboxy group, and an aminocarbonyl group , the manufacturing method according to claim (1) or (2). (4) Nitrobenzene is 2-fluoronitrobenzene,
4-fluoronitrobenzene, 2-nitroanisole,
The manufacturing method according to claim (3), which is 2-nitrobenzotrifluoride, 3-nitrophenol, or 4-fluoro-3-nitrophenol. (5) the cell is partitioned by a cation exchange membrane;
A manufacturing method according to any one of claims (1) to (4). (6) The production method according to any one of claims (2) to (5), wherein the organic solvent is selected from C(2-4) alkanol, acetone, tetrahydrofuran, acetonitrile, and acetic acid. . (7) The organic solvent is ethanol, propan-1-ol,
The manufacturing method according to claim (6), wherein the method is selected from propan-2-ol and acetic acid. (8) The manufacturing method according to any one of claims (2) to (7), wherein the volume percentage of the organic solvent in the medium is in the range of 5 to 30. (9) Claims (1) to (8) in which the concentration of hydrohalic acid in the medium is in the range of 3 to 10 molar concentrations.
) The manufacturing method described in any one of paragraphs. (10) The manufacturing method according to any one of claims (1) to (9), wherein the temperature is in the range of 40 to 60°C.