EP0179289A1 - Method for producing aromatic carboxylic esters - Google Patents

Method for producing aromatic carboxylic esters Download PDF

Info

Publication number
EP0179289A1
EP0179289A1 EP85112060A EP85112060A EP0179289A1 EP 0179289 A1 EP0179289 A1 EP 0179289A1 EP 85112060 A EP85112060 A EP 85112060A EP 85112060 A EP85112060 A EP 85112060A EP 0179289 A1 EP0179289 A1 EP 0179289A1
Authority
EP
European Patent Office
Prior art keywords
tris
amine
weight
formula
mit
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP85112060A
Other languages
German (de)
French (fr)
Other versions
EP0179289B1 (en
Inventor
Dieter Dr. Degner
Eberhard Prof. Dr. Steckhan
Karl Heinz Dr. Grosse-Brinkhaus
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BASF SE
Original Assignee
BASF SE
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by BASF SE filed Critical BASF SE
Publication of EP0179289A1 publication Critical patent/EP0179289A1/en
Application granted granted Critical
Publication of EP0179289B1 publication Critical patent/EP0179289B1/en
Expired legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B3/00—Electrolytic production of organic compounds
    • C25B3/20—Processes
    • C25B3/23—Oxidation

Definitions

  • This invention relates to a new process for the preparation of aromatic carboxylic acid esters by electrooxidation of benzene derivatives.
  • R represents an alkyl radical having 1 to 4 carbon atoms, preferably a methyl or ethyl radical.
  • alkyl radicals for example those having 1 to 6 carbon atoms, are suitable as R 1 .
  • Alkoxy groups are, for example, hethoxy or ethoxy groups.
  • Aryl and aryloxy groups are, for example, phenyl and phenoxy groups.
  • acyl and acyloxy groups for example, -CO-CH 3 or -COOCH 3 may be mentioned .
  • Starting materials of the formula II are, for example, toluenes, such as toluene, o-, m-, p-xylene, 4-tert-butyltoluene, 4-methoxitoluene, 4-chlorotoluene, 4-bromotoluene or benzaldehyde dialkyl acetals, such as benzaldehyde dimethyl acetal.
  • toluenes such as toluene, o-, m-, p-xylene
  • 4-tert-butyltoluene 4-methoxitoluene
  • 4-chlorotoluene 4-bromotoluene
  • benzaldehyde dialkyl acetals such as benzaldehyde dimethyl acetal.
  • Triarylamine compounds of the formula III are compounds of the formulas
  • halogen atoms they contain e.g. F, Cl or Br atoms.
  • Compounds of formula III are e.g. Tris (4-bromophenyl) amine, bis (4-bromophenyl) - (2,4-dibromophenyl) amine, bis (2.4-dibromophenyl) - (4-bromophenyl) amine, tris (2.4 -dibromophenyl) amine, tris (4-chlorophenyl) amine, bis (4-chlorophenyl) - (2,4-dichlorophenyl) amine, bis (2,4-dichlorophenyl) - (4-chlorophenyl) - amine and tris (2,4-dichlorophenyl) amine, of which tris (2,4-dibromophenyl) amine and tris (2,4-dichlorophenyl) amine are preferred.
  • the method according to the invention does not require a special electrolysis cell; an undivided flow cell is preferably used.
  • All anode materials which are conventional per se and which are stable under the electrolysis conditions, such as noble metals, e.g. Gold or platinum.
  • Graphite and glassy carbon are preferably used.
  • the cathode material includes Graphite, iron, steel, nickel or even precious metals, such as platinum, are suitable.
  • Suitable conducting salts are the conducting salts customary in organic electrochemistry, such as salts of tetrafluoroboric acid, salts of alkyl or arylsulfonic acids or salts of alkylsulfuric acids and salts of perchloric acid.
  • cosolvents can be added to the electrolyte.
  • co-solvents e.g. Halogenated hydrocarbons, such as methylene chloride, dichloroethane, 1,2-dichloropropane or nitriles, such as acetonitrile.
  • the cosolvents are added to the alkanol e.g. in amounts up to 60 parts by weight per 100 parts by weight of alkanol.
  • M an electrolyzed at current densities of 0.25 to 5 A / dm 2 , preferably at 0.5 to 3 A / d m2.
  • the upper limit of the electrolysis temperatures is the boiling point of the alkanol or the cosolvent.
  • electrolysis is carried out at temperatures of e.g. 10 to 5 ° C below the boiling point of the electrolyte.
  • methanol e.g. at temperatures up to 60 ° C, preferably at 20 to 60 ° C, electrolyzed. It was surprisingly found that the process according to the invention offers the possibility of largely converting the benzene derivatives of the formula II without the selectivity of the electrooxidation being impaired.
  • the processing of the electrolysis outputs is carried out according to known methods.
  • the electrolysis discharge is expediently worked up by distillation. Excess alkanol and any cosolvent used are first distilled off, conductive salt and triarylamino compound are filtered off and the aromatic carboxylic acid esters are distilled off. Alkanol, cosolvent, conductive salt and triarylamino compound can be recycled to the electrolysis. After 2500 regenerative cycles, no significant loss of triarylamine compound was found.
  • the carboxylic acid esters obtainable by the process according to the invention are fragrance substances and intermediate products for dyes and pharmaceuticals.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

Verfahren zur Herstellung von aromatischen Carbonsäureestern durch Elektrooxidation der entsprechenden Methylbenzole oder Benzaldehyddialkylacetale in Gegenwart von Alkanolen und halogenierten Triarylaminderivaten.Process for the preparation of aromatic carboxylic acid esters by electrooxidation of the corresponding methylbenzenes or benzaldehyde dialkyl acetals in the presence of alkanols and halogenated triarylamine derivatives.

Description

Diese Erfindung betrifft ein neues Verfahren zur Herstellung von aromatischen Carbonsäureestern durch Elektrooxidation von Benzolderivaten.This invention relates to a new process for the preparation of aromatic carboxylic acid esters by electrooxidation of benzene derivatives.

Aus J. Chem. Soc. Perkin I, 1978, 708 und der DE-PS 28 48 397 ist bekannt, daß man Toluole durch anodische Oxidation in Gegenwart von Methanol selektiv in die entsprechenden Benzaldehyddimethylacetale überführen kann. Eine elektrochemische Oxidation der Toluole oder der Benzaldehyddialkylacetale zu den entsprechenden Estern gelingt jedoch auch bei Anwendung eines sehr hohen Stromüberschußes nur mit sehr geringer Selektivität.From J. Chem. Soc. Perkin I, 1978, 708 and DE-PS 28 48 397 it is known that toluenes can be converted selectively into the corresponding benzaldehyde dimethyl acetals by anodic oxidation in the presence of methanol. However, electrochemical oxidation of the toluenes or of the benzaldehyde dialkyl acetals to the corresponding esters is only possible with very low selectivity even when a very large excess of current is used.

Es wurde nun gefunden, daß man aromatische Carbonsäureester der allgemeinen Formel

Figure imgb0001
in der R einen Alkylrest mit 1 bis 4 C-Atomen und R1 ein Wasserstoffatom, ein Halogenatom oder einen Alkyl-, Aryl-, Heteroaryl-, Alkoxi-, Aryloxi-, Acyl-, Acyloxi- oder Cyanrest bedeuten, durch Elektrooxidation von Benzolderivaten der allgemeinen Formel
Figure imgb0002
in der R2 für Methyl oder einen Rest der Formel -CH(OR)2 steht und R und R1 die obengenannte Bedeutung haben, mit einem Alkohol der Formel ROH besonders vorteilhaft herstellen kann, wenn man die Elektrooxidation in Gegenwart einer Triarylaminverbindung der allgemeinen Formel
Figure imgb0003
in der beide A entweder Wasserstoffatome oder zusammen eine Einfachbindung, X ein Halogenatom oder einen,H3COC- oder NC-Rest, Y ein Wasserstoffatom oder ein Halogenatom und Z ein Wasserstoffatom oder ein Halogenatom bedeuten, durchführt. Nach dem neuen Verfahren erhält man die Carbonsäureester überraschenderweise in guter Selektivität.It has now been found that aromatic carboxylic acid esters of the general formula
Figure imgb0001
 in which R is an alkyl radical having 1 to 4 carbon atoms and R 1 is a hydrogen atom, a halogen atom or an alkyl, aryl, heteroaryl, alkoxy, aryloxy, acyl, acyloxy or cyano radical, by electrooxidation of benzene derivatives the general formula
Figure imgb0002
 in which R2 represents methyl or a radical of the formula -CH (OR) 2 and R and R 1 have the meaning given above, can be produced particularly advantageously with an alcohol of the formula ROH if the electrooxidation is carried out in the presence of a triarylamine compound of the general formula
Figure imgb0003
 in which both A represents either hydrogen atoms or together represent a single bond, X represents a halogen atom or one, H 3 COC or NC radical, Y represents a hydrogen atom or a halogen atom and Z represents a hydrogen atom or a halogen atom. The new process surprisingly gives the carboxylic acid esters with good selectivity.

In den Benzolderivaten der Formel II steht R für einen Alkylrest mit 1 bis 4 C-Atomen, vorzugsweise für einen Methyl- oder Ethylrest. Als Reste R1 kommen neben Wasserstoffatomen und Halogenatomen Alkylreste, z.B. solche mit 1 bis 6 C-Atomen in Betracht. Alkoxigruppen sind z.B. Hethoxi- oder Ethoxigruppen. Aryl- und Aryloxigruppen sind z.B. Phenyl- und Phenoxigruppen. Als Acyl- und Acyloxigruppen seien z.B. -CO-CH3 oder -COOCH3 genannt.In the benzene derivatives of the formula II, R represents an alkyl radical having 1 to 4 carbon atoms, preferably a methyl or ethyl radical. In addition to hydrogen atoms and halogen atoms, alkyl radicals, for example those having 1 to 6 carbon atoms, are suitable as R 1 . Alkoxy groups are, for example, hethoxy or ethoxy groups. Aryl and aryloxy groups are, for example, phenyl and phenoxy groups. As acyl and acyloxy groups, for example, -CO-CH 3 or -COOCH 3 may be mentioned .

Ausgangsstoffe der Formel II sind z.B. Toluole, wie Toluol, o-, m-, p-Xylol, 4-tert.Butyltoluol, 4-Methoxitoluol, 4-Chlortoluol, 4-Bromtoluol oder Benzaldehyddialkylacetale, wie Benzaldehyddimethylacetal. Benzaldehyddiethylacetal, 4-Methylbenzaldehyddimethylacetal, 4-tert.Butyl- benzaldehyddimethylacetal, 4-tert.Butoxibenzaldehyddimethylacetal, 4-Methoxibenzaldehyddimethylacetal, 4-Brombenzaldehyddimethylacetal, 4-Chlorbenzaldehyddimethylacetal. Von den Alkanolen der Formel ROH wird Methanol bevorzugt. Triarylaminverbindungen der Formel III sind Verbindungen der Formeln

Figure imgb0004
Starting materials of the formula II are, for example, toluenes, such as toluene, o-, m-, p-xylene, 4-tert-butyltoluene, 4-methoxitoluene, 4-chlorotoluene, 4-bromotoluene or benzaldehyde dialkyl acetals, such as benzaldehyde dimethyl acetal. Benzaldehyde diethylacetal, 4-methylbenzaldehyde dimethyl acetal, 4-tert-butyl-benzaldehyde dimethyl acetal, 4-tert-butoxybenzaldehyde dimethyl acetal, 4-methoxybenzaldehyde dimethyl acetal, 4-bromobenzaldehyde dimethyl acetal, 4-chlorobenzaldehyde dimethylacetal. Of the alkanols of the formula ROH, methanol is preferred. Triarylamine compounds of the formula III are compounds of the formulas
Figure imgb0004

Sie enthalten als Halogenatome z.B. F-, Cl-oder Br-Atome. Verbindungen der Formel III sind z.B. Tris-(4-bromphenyl)-amin, Bis-(4-bromphenyl)-(2,4-dibromphenyl)-amin, Bis-(2.4-dibromphenyl)-(4-bromphenyl)-amin, Tris-(2,4-dibromphenyl)-amin, Tris-(4-chlorphenyl)-amin, Bis-(4-chlorphenyl)-(2,4-dichlorphenyl)-amin, Bis-(2,4-dichlorphenyl)-(4-chlorphenyl)-amin und Tris-(2.4-dichlorphenyl)-amin, von denen Tris-(2,4-dibromphenyl)-amin und Tris-(2,4-dichlorphenyl)-amin bevorzugt sind.As halogen atoms they contain e.g. F, Cl or Br atoms. Compounds of formula III are e.g. Tris (4-bromophenyl) amine, bis (4-bromophenyl) - (2,4-dibromophenyl) amine, bis (2.4-dibromophenyl) - (4-bromophenyl) amine, tris (2.4 -dibromophenyl) amine, tris (4-chlorophenyl) amine, bis (4-chlorophenyl) - (2,4-dichlorophenyl) amine, bis (2,4-dichlorophenyl) - (4-chlorophenyl) - amine and tris (2,4-dichlorophenyl) amine, of which tris (2,4-dibromophenyl) amine and tris (2,4-dichlorophenyl) amine are preferred.

Das erfindungsgemäße Verfahren benötigt keine besondere Elektrolysezelle, bevorzugt wird eine ungeteilte Durchflußzelle eingesetzt. Als Anoden können alle an sich üblichen Anodenmaterialien eingesetzt werden, die unter den Elektrolysebedingungen stabil sind, wie Edelmetalle, z.B. Gold oder Platin. Bevorzugt verwendet man Graphit sowie glasartigen Kohlenstoff. Als Kathodenmaterial sind u.a. Graphit, Eisen, Stahl, Nickel oder auch Edelmetalle, wie Platin, geeignet.The method according to the invention does not require a special electrolysis cell; an undivided flow cell is preferably used. All anode materials which are conventional per se and which are stable under the electrolysis conditions, such as noble metals, e.g. Gold or platinum. Graphite and glassy carbon are preferably used. The cathode material includes Graphite, iron, steel, nickel or even precious metals, such as platinum, are suitable.

Der bei der Elektrooxidation eingesetzte Elektrolyt hat beispielsweise folgende Zusammensetzung:

  • 1 bis 70 Gew.-% Ausgangsverbindung der Formel II
  • 30 bis 96 Gew.-X Alkanol mit oder ohne Kolösungsmittel
  • 0,5 bis 5 Gew.-X Triarylaminverbindung der Formel III
  • 0,5 bis 4 Gew.-X Leitsalz
The electrolyte used in electrooxidation has the following composition, for example:
  • 1 to 70% by weight of starting compound of the formula II
  • 30 to 96% by weight alkanol with or without cosolvent
  • 0.5 to 5% by weight of triarylamine compound of the formula III
  • 0.5 to 4% by weight of conductive salt

Als Leitsalze kommen die in der organischen Elektrochemie üblichen Leitsalze, wie Salze der Tetrafluorborsäure, Salze von Alkyl- oder Arylsulfonsäuren oder Salze von Alkylschwefelsäuren sowie Salze der Perchlorsäure in Betracht. Zur Erhöhung der Löslichkeit des Elektronenüberträgers können dem Elektrolyten Kolösungsmittel zugesetzt werden. Als Kolösungsmittel kommen z.B. Halogenkohlenwasserstoffe, wie Methylenchlorid, Dichlorethan, 1,2-Dichlorpropan oder Nitrile, wie Acetonitril in Betracht. Die Kolösungsmittel werden dem Alkanol z.B. in Mengen bis zu 60 Gewichtsteilen pro 100 Gewichtsteile Alkanol zugegeben.Suitable conducting salts are the conducting salts customary in organic electrochemistry, such as salts of tetrafluoroboric acid, salts of alkyl or arylsulfonic acids or salts of alkylsulfuric acids and salts of perchloric acid. To increase the solubility of the electron carrier, cosolvents can be added to the electrolyte. As co-solvents e.g. Halogenated hydrocarbons, such as methylene chloride, dichloroethane, 1,2-dichloropropane or nitriles, such as acetonitrile. The cosolvents are added to the alkanol e.g. in amounts up to 60 parts by weight per 100 parts by weight of alkanol.

Man elektrolysiert bei Stromdichten von 0,25 bis 5 A/dm2, bevorzugt bei 0,5 bis 3 A/dm2. M an electrolyzed at current densities of 0.25 to 5 A / dm 2 , preferably at 0.5 to 3 A / d m2.

Die Elektrolysetemperaturen sind nach oben hin durch den Siedepunkt des Alkanols bzw. des Kolösungsmittels begrenzt. Zweckmäßigerweise elektrolysiert man bei Temperaturen von z.B. 10 bis 5°C unterhalb des Siedepunktes des Elektrolyten. Bei Verwendung von Methanol wird z.B. bei Temperaturen bis 60°C, vorzugsweise bei 20 bis 60°C, elektrolysiert. Es wurde überraschend festgestellt, daß das erfindungsgemäße Verfahren die Möglichkeit bietet, die Benzolderivate der Formel II weitgehend umzusetzen, ohne daß es zu einer Verschlechterung der Selektivität der Elektrooxidation kommt.The upper limit of the electrolysis temperatures is the boiling point of the alkanol or the cosolvent. Advantageously, electrolysis is carried out at temperatures of e.g. 10 to 5 ° C below the boiling point of the electrolyte. When using methanol e.g. at temperatures up to 60 ° C, preferably at 20 to 60 ° C, electrolyzed. It was surprisingly found that the process according to the invention offers the possibility of largely converting the benzene derivatives of the formula II without the selectivity of the electrooxidation being impaired.

Die Aufarbeitung der Elektrolysenausträge nimmt man nach an sich bekannten Methoden vor. Zweckmäßigerweise wird der Elektrolyseaustrag destillativ aufgearbeitet. Überschüssiges Alkanol und evtl. eingesetztes Kolösungsmittel werden zunächst abdestilliert, Leitsalz und Triarylaminoverbindung werden abfiltriert und die aromatischen Carbonsäureester werden reindestilliert. Alkanol, Kolösungsmittel, Leitsalz und Triarylaminoverbindung können zur Elektrolyse zurückgeführt werden. Nach 2500 regenerativen Zyklen konnte noch kein nennenswerter Verlust an Triarylaminverbindung festgestellt werden.The processing of the electrolysis outputs is carried out according to known methods. The electrolysis discharge is expediently worked up by distillation. Excess alkanol and any cosolvent used are first distilled off, conductive salt and triarylamino compound are filtered off and the aromatic carboxylic acid esters are distilled off. Alkanol, cosolvent, conductive salt and triarylamino compound can be recycled to the electrolysis. After 2500 regenerative cycles, no significant loss of triarylamine compound was found.

Die nach dem erfindungsgemäßen Verfahren erhältlichen Carbonsäureester sind Riechstoffe sowie Vorprodukte für Farbstoffe und Pharmaka.The carboxylic acid esters obtainable by the process according to the invention are fragrance substances and intermediate products for dyes and pharmaceuticals.

Beispiel 1example 1

Elektrosynthese von Benzoesäuremethylester

  • Zelle: Ungeteilte Becherglaszelle mit Kühlmantel
  • Anode: Zylinder aus glasartigem Kohlenstoff
    Figure imgb0005
    = 26 mm; Höhe = 50 mm.
  • Kathode: Platindraht
  • Einsatz: 720 mg (1 mmol) Tris(2,4-dibromphenyl)amin 920 mg (10 mmol) Toluol
  • Elektrolyt: CH3OH/CH2Cl2 (3 : 1); 1.5 Gew.-% NaClO4; 8,7 Gew.-% Tris(2,4-dibromphenyl)amin; 1 Gew.-% Toluol
  • Stromdichte: 0,5 bis 0,7 A/dm2
  • Elektrolyse mit 15,5 F/Mol Toluol
  • Temperatur: 30°C
  • Aufarbeitung: Die Elektrolyselösung wird auf das halbe Volumen eingeengt, mit 20 ml Wasser versetzt und mit Pentan perforiert. Nach Trocknen und Abrotieren des Pentans werden die Produkte durch Kugelrohrdestillation abgetrenat und gereinigt.
  • Ergebnis:
  • Umsatz: 80 %
  • Ausbeute an Benzoesäuremethylester: 1.037 g ≙ 76 %
  • Selektivität: 95 %.
Electrosynthesis of methyl benzoate
  • Cell: undivided beaker cell with cooling jacket
  • Anode: cylinder made of glassy carbon
    Figure imgb0005
    = 26 mm; Height = 50 mm.
  • Cathode: platinum wire
  • Use: 720 mg (1 mmol) tris (2,4-dibromophenyl) amine 920 mg (10 mmol) toluene
  • Electrolyte: CH 3 OH / CH 2 Cl 2 (3: 1); 1.5 % by weight NaClO 4 ; 8.7% by weight of tris (2,4-dibromophenyl) amine; 1 wt% toluene
  • Current density: 0.5 to 0.7 A / dm 2
  • Electrolysis with 15.5 F / mol toluene
  • Temperature: 30 ° C
  • Working up: The electrolysis solution is concentrated to half the volume, mixed with 20 ml of water and perforated with pentane. After drying and spinning off the pentane, the products are separated and purified by bulb tube distillation.
  • Result:
  • Turnover: 80%
  • Yield of methyl benzoate: 1,037 g ≙ 76%
  • Selectivity: 95%.

Beispiel 2Example 2

Elektrosynthese von p-Hethylbenzoesäuremethylester

  • Zelle: Ungeteilte Becherglaszelle mit Kühlmantel
  • Anode: Zylinder aus glasartigem Kohlenstoff
    Figure imgb0006
    = 26 mm; Höhe = 50 mm.
  • Kathode: Platindraht
  • Einsatz: 720 mg (1 mmol) Tris(2,4-dibromphenyl)amin 1,06 g (10 mmol) p-Xylol
  • Elektrolyt: CH3OH/CH2Cl2 (3 : 1); 1,5 Gew.-% NaClO4; 8,7 Gew.-% Tris(2,4-dibromphenyl)amin; 1 Gew.-% p-Xylol
  • Stromdichte: 0,5 bis 0,7 A/dm2
  • Elektrolyse mit 9,7 F/Mol p-Xylol
  • Temperatur: 30°C
  • Aufarbeitung: Die Elektrolyselösung wird auf das halbe Volumen eingeengt, mit 20 ml Wasser versetzt und mit Pentan perforiert. Nach Trocknen und Abrotieren des Pentans werden die Produkte durch Kugelrohrdestillation abgetrenant und gereinigt.
  • Ergebnis: Umsatz: 95 %
  • Ausbeute an p-Methylbenzoesäuremethylester: 1,101 g ≙ 73 % Selektivität: 77 %.
  • Beispiel 3
  • Elektrosynthese von 4-t-Butylbenzoesäuremethylester
  • Zelle: Ungeteilte Becherglaszelle mit Kühlmantel
  • Anode: Zylinder aus glasartigem Kohlenstoff Ø = 26 mm; Höhe = 50 mm.
  • Kathode: Platindraht
  • Einsatz: 720 mg (1 mmol) Tris(2.4-dibromphenyl)amin 1,480 g (10 mmol) 4-t-Butyltoluol
  • Elektrolyt: CH3OH/CH2Cl2 (3 : 1); 1,5 Gew.-% NaC104; 0,7 Gew.-% Tris(2,4-dibromphenyl)amin; 1,5 Gew.-% 4-t-Butyltoluol
  • Stromdichte: 0,5 bis 0,7 A/dm2
  • Elektrolyse mit 11,1 F/Hol 4-t-Butyltoluol
  • Temperatur: 30°C
  • Aufarbeitung: Die Elektrolyselösung wird auf das halbe Volumen eingeengt, mit 20 ml Wasser versetzt und mit Pentan perforiert. Nach Trocknen und Abrotieren des Pentans werden die Produkte durch Kugelrohrdestillation abgetrennt und gereinigt.
  • Ergebnis:
  • Umsatz: 98 %
  • Ausbeute an 4-tert.-Butylbenzoesäuremethylester: 1,382 g ≙ 72 %
  • Selektivität: 73 %.
  • Beispiel 4
  • Elektrosynthese von p-Methylbenzoesäuremethylester
  • Zelle: Ungeteilte Becherglaszelle mit Kühlmantel
  • Anode: Zylinder aus glasartigen Kohlenstoff Ø = 26 mm; Höhe = 50 mm.
  • Kathode: Platindraht
  • Einsatz: 720 mg (1 mmol) Tris(2,4-dibromphenyl)amin
  • 1,66 g (10 mmol) 4-Methylbenzaldehyddimethylacetal Elektrolyt: CH3OH/CH2Cl2 (3 : 1); 1.5 Gew.-% NaClO4; 0,7 Gew.-% Tris(2,4-dibromphenyl)amin; 1,6 Gew.-% 4-Methylbenzaldehyddimethylacetal
  • Stromdichte: 0,5 bis 0,7 A/dm2
  • Elektrolyse mit 3,3 F/Mol 4-Methylbenzaldehyddimethylacetal Temperatur: 30°C
  • Aufarbeitung: Die Elektrolyselösung wird auf das halbe Volumen eingeengt,
  • mit 20 ml Wasser versetzt und mit Pentan perforiert. Nach Trocknen und Abrotieren des Pentans werden die Produkte durch Kugelrohrdestillation abgetrennt und gereinigt. Ergebnis:
  • Umsatz: 87 X Ausbeute an p-Methylbenzoesäuremethylester: 1,28 g ≙ 85 % Selektivität: 98 %.
Electrosynthesis of methyl p-ethylbenzoate
  • Cell: undivided beaker cell with cooling jacket
  • Anode: cylinder made of glassy carbon
    Figure imgb0006
    = 26 mm; Height = 50 mm.
  • Cathode: platinum wire
  • Use: 720 mg (1 mmol) tris (2,4-dibromophenyl) amine 1.06 g (10 mmol) p-xylene
  • Electrolyte: CH 3 OH / CH 2 Cl 2 (3: 1); 1.5% by weight NaClO 4 ; 8.7% by weight of tris (2,4-dibromophenyl) amine; 1% by weight p-xylene
  • Current density: 0.5 to 0.7 A / dm 2
  • Electrolysis with 9.7 F / mol p-xylene
  • Temperature: 30 ° C
  • Working up: The electrolysis solution is concentrated to half the volume, mixed with 20 ml of water and perforated with pentane. After drying and spinning off the pentane, the products are separated and purified by bulb tube distillation.
  • Result: sales: 95%
  • Yield of methyl p-methylbenzoate: 1.101 g ≙ 73% selectivity: 77%.
  • Example 3
  • Electrosynthesis of 4-t-butylbenzoic acid methyl ester
  • Cell: undivided beaker cell with cooling jacket
  • Anode: cylinder made of glassy carbon Ø = 26 mm; Height = 50 mm.
  • Cathode: platinum wire
  • Use: 720 mg (1 mmol) tris (2.4-dibromophenyl) amine 1.480 g (10 mmol) 4-t-butyltoluene
  • Electrolyte: CH 3 OH / CH 2 Cl 2 (3: 1); 1.5% by weight NaC10 4 ; 0.7% by weight of tris (2,4-dibromophenyl) amine; 1.5% by weight of 4-t-butyltoluene
  • Current density: 0.5 to 0.7 A / dm 2
  • Electrolysis with 11.1 F / Hol 4-t-butyltoluene
  • Temperature: 30 ° C
  • Working up: The electrolysis solution is concentrated to half the volume, mixed with 20 ml of water and perforated with pentane. After drying and spinning off the pentane, the products are separated and purified by bulb tube distillation.
  • Result:
  • Turnover: 98%
  • Yield of 4-tert-butylbenzoic acid methyl ester: 1.382 g ≙ 72%
  • Selectivity: 73%.
  • Example 4
  • Electrosynthesis of methyl p-methylbenzoate
  • Cell: undivided beaker cell with cooling jacket
  • Anode: cylinder made of glassy carbon Ø = 26 mm; Height = 50 mm.
  • Cathode: platinum wire
  • Use: 720 mg (1 mmol) tris (2,4-dibromophenyl) amine
  • 1.66 g (10 mmol) 4-methylbenzaldehyde dimethyl acetal electrolyte: CH 3 OH / CH 2 Cl 2 (3: 1); 1.5% by weight NaClO 4 ; 0.7% by weight of tris (2,4-dibromophenyl) amine; 1.6 wt% 4-methylbenzaldehyde dimethyl acetal
  • Current density: 0.5 to 0.7 A / dm 2
  • Electrolysis with 3.3 F / mol of 4-methylbenzaldehyde dimethyl acetal temperature: 30 ° C
  • Work up: The electrolysis solution is concentrated to half the volume,
  • mixed with 20 ml of water and perforated with pentane. After drying and spinning off the pentane, the products are separated and purified by bulb tube distillation. Result:
  • Conversion: 87 X yield of methyl p-methylbenzoate: 1.28 g ≙ 85% selectivity: 98%.

Beispiel 5Example 5

Elektrosynthese von 4-tert.-Butoxybenzoesäuremethylester

  • Zelle: Ungeteilte Becherglaszelle mit Kühlmantel
  • Anode: Zylinder aus glasartigem Kohlenstoff Ø = 26 mm; Höhe = 50 mm.
  • Kathode: Platindraht
  • Einsatz: 720 mg (1 mmol) Tris(2.4-dibromphenyl)amin 2,24 g (10 mmol) 4-tert.-Butoxybenzaldehyddimethylacetal
  • Elektrolyt: CH3OH/CH2Cl2 (3 : 1); 1,5 Gew.-% NaC104; 0,7 Gew.-% Tris(2,4-dibromphenyl)amin; 2,2 Gew.-% 4-tert.-Butoxybenz- aldehyddimethylacetal
  • Stromdichte: 0,5 bis 0,7 A/dm2
  • Elektrolyse mit 4 F/Mol 4-tert.-Butoxybenzaldehyddimethylacetal Temperatur: 30°C
  • Aufarbeitung: Die Elektrolyselösung wird auf das halbe Volumen eingeengt,
  • mit 20 ml Wasser versetzt und mit Pentan perforiert. Nach Trocknen und Abrotieren des Pentans werden die Produkte durch Kugelrohrdestillation abgetrennt und gereinigt. Ergebnis:
  • Umsatz: 96 %
  • Ausbeute an 4-tert.Butoxybenzoesäuremethylester: 1,86 g ≙ 89 % Selektivität: 93 %.
Electrosynthesis of 4-tert-butoxybenzoic acid methyl ester
  • Cell: undivided beaker cell with cooling jacket
  • Anode: cylinder made of glassy carbon Ø = 26 mm; Height = 50 mm.
  • Cathode: platinum wire
  • Use: 720 mg (1 mmol) tris (2.4-dibromophenyl) amine 2.24 g (10 mmol) 4-tert-butoxybenzaldehyde dimethyl acetal
  • Electrolyte: CH 3 OH / CH 2 Cl 2 (3: 1); 1.5% by weight NaC10 4 ; 0.7% by weight of tris (2,4-dibromophenyl) amine; 2.2% by weight of 4-tert-butoxybenzaldehyde dimethyl acetal
  • Current density: 0.5 to 0.7 A / dm 2
  • Electrolysis with 4 F / mol of 4-tert-butoxybenzaldehyde dimethyl acetal temperature: 30 ° C
  • Workup: The electrolysis solution is concentrated to half the volume,
  • mixed with 20 ml of water and perforated with pentane. After drying and spinning off the pentane, the products are separated and purified by bulb tube distillation. Result:
  • Turnover: 96%
  • Yield of 4-tert-butoxybenzoic acid methyl ester: 1.86 g ≙ 89% selectivity: 93%.

Beispiel 6 (Vergleichsversuch)Example 6

Elektrosynthese von p-Methylbenzoesäuremethylester

  • Zelle: Ungeteilte Becherglaszelle mit 11 bipolaren Graphitelektroden Anode: Graphit
  • Kathode: Graphit
  • Elektrolyt: 3204 g CH30H 360 g (2,17 mol) 4-Methylbenzaldehyddimethylacetal 36 g KSO3C6H5
  • Stromdichte: 3,3 A/dm2
  • Elektrolyse mit 10 F/Mol 4-Methylbenzaldehyddimethylacetal Temperatur 25 bis 30°C. Der Elektrolyt wird während der Elektrolyse mit 200 1/h über einen Wärmeaustauscher gepumpt. Nach Beendigung der Elektrolyse wird Methanol bei Normal-Aufarbeitung: druck abdestilliert, das Leitsalz abfiltriert und das Filtrat bei 2 mbar und 73 bis 152°C fraktioniert destilliert.
  • Hierbei erhält man neben 56.6 g unumgesetzten 4-Methylbenzaldehyddimethylacetal 21 g 4-Methylbenzoesäuremethylester. Ergebnis: Umsatz: 84 %
  • Ausbeute an 4-Methylbenzoesäuremethylester: 6 %
  • Selektivität: 8 %.
Electrosynthesis of methyl p-methylbenzoate
  • Cell: Undivided beaker cell with 11 bipolar graphite electrodes Anode: graphite
  • Cathode: graphite
  • Electrolyte: 3204 g CH 30H 360 g (2.17 mol) 4-methylbenzaldehyde dimethylacetal 3 6 g KSO 3 C 6 H 5
  • Current density: 3.3 A / dm2
  • Electrolysis with 10 F / mol 4-methylbenzaldehyde dimethyl acetal temperature 25 to 30 ° C. The electrolyte is pumped through a heat exchanger at 200 l / h during the electrolysis. After the electrolysis has ended, methanol is distilled off under normal work-up: pressure, the conductive salt is filtered off and the filtrate is fractionally distilled at 2 mbar and 73 to 152 ° C.
  • In addition to 56.6 g of unreacted 4-methylbenzaldehyde dimethyl acetal, 21 g of 4-methylbenzoic acid methyl ester are obtained. Result: sales: 84%
  • Yield of 4-methylbenzoic acid methyl ester: 6%
  • Selectivity: 8%.

Claims (3)

1. Verfahren zur Herstellung aromatischer Carbonsäureester der allgemeinen Formel
Figure imgb0007
in der R einen Alkylrest mit 1 bis 4 C-Atomen und R1 ein Wasserstoff atom, ein Halogenatom oder einen Alkyl-, Aryl-, Heteroaryl-, Alkoxi-Aryloxi-, Acyl-, Acyloxi- oder Cyanrest bedeuten. durch Elektrooxidation von Benzolderivaten der allgemeinen Formel
Figure imgb0008
in der R2 für Methyl oder einen Rest der Formel -CH(OR)2 steht und R und R1 die obengenannte Bedeutung haben, mit einem Alkohol der Formel ROH, dadurch gekennzeichnet, daß man die Elektrooxidation in Gegenwart einer Triarylaminverbindung der allgemeinen Formel
Figure imgb0009
in der beide A entweder Wasserstoffatome oder zusammen eine Einfachbindung, X ein Halogenatom oder einen H3COC- oder NC-Rest. Y ein Wasserstoffatom oder ein Halogenatom und Z ein Wasserstoffatom oder ein Halogenatom bedeuten, durchführt.1. Process for the preparation of aromatic carboxylic acid esters of the general formula
Figure imgb0007
 in which R is an alkyl radical having 1 to 4 carbon atoms and R 1 is a hydrogen atom, a halogen atom or an alkyl, aryl, heteroaryl, alkoxy-aryloxy, acyl, acyloxy or cyano radical. by electrooxidation of benzene derivatives of the general formula
Figure imgb0008
 in which R 2 is methyl or a radical of the formula -CH (OR) 2 and R and R 1 have the meaning given above, with an alcohol of the formula ROH, characterized in that the electrooxidation in the presence of a triarylamine compound of the general formula
Figure imgb0009
 in which both A are either hydrogen atoms or together a single bond, X is a halogen atom or an H 3 COC or NC radical. Y represents a hydrogen atom or a halogen atom and Z represents a hydrogen atom or a halogen atom. 2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß man als Triarylaminverbindung Tris-(2,4-dibromphenyl)-amin oder Tris-(2,4-dichlorphenyl)-amin verwendet.2. The method according to claim 1, characterized in that tris (2,4-dibromophenyl) amine or tris (2,4-dichlorophenyl) amine is used as the triarylamine compound. 3. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß man einen Elektrolyten verwendet, der einen Gehalt an Benzolderivat der Formel II von 1 bis 70 Gew.-X, an Alkanol mit oder ohne Kolösungsmittel, von 30 bis 96 Gew.-X, an Triarylaminverbindung von 0,5 bis 5 Gew.-Z und an Leitsalz von 0,5 bis 4 Gew.-% aufweist.3. The method according to claim 1, characterized in that an electrolyte is used which has a benzene derivative of the formula II of 1 to 70% by weight, of alkanol with or without cosolvent, of 30 to 96% by weight Triarylamine compound of 0.5 to 5 wt .-% and of conducting salt from 0.5 to 4 wt .-%.
EP85112060A 1984-09-27 1985-09-24 Method for producing aromatic carboxylic esters Expired EP0179289B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3435388 1984-09-27
DE19843435388 DE3435388A1 (en) 1984-09-27 1984-09-27 METHOD FOR PRODUCING AROMATIC CARBONIC ACID ESTERS

Publications (2)

Publication Number Publication Date
EP0179289A1 true EP0179289A1 (en) 1986-04-30
EP0179289B1 EP0179289B1 (en) 1987-07-08

Family

ID=6246448

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85112060A Expired EP0179289B1 (en) 1984-09-27 1985-09-24 Method for producing aromatic carboxylic esters

Country Status (3)

Country Link
US (1) US4612092A (en)
EP (1) EP0179289B1 (en)
DE (2) DE3435388A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0212509A1 (en) * 1985-08-14 1987-03-04 BASF Aktiengesellschaft Process for manufacturing benzoic-acid orthoesters, and compounds of this class
WO2002020446A1 (en) * 2000-09-06 2002-03-14 Basf Aktiengesellschaft Method for producing orthocarbonic acid trialkyl esters

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3529531A1 (en) * 1985-08-17 1987-02-26 Basf Ag METHOD FOR PRODUCING CARBAMID ACID ESTERS
US5306411A (en) * 1989-05-25 1994-04-26 The Standard Oil Company Solid multi-component membranes, electrochemical reactor components, electrochemical reactors and use of membranes, reactor components, and reactor for oxidation reactions
DE3708337A1 (en) * 1987-03-14 1988-09-22 Basf Ag METHOD FOR PRODUCING METHOXIACETALDEHYDDIALKYLACETALS
CN110483311B (en) * 2019-09-25 2022-12-23 上海市计量测试技术研究院 Method for synthesizing pentadeuterium-substituted malachite green salt

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3347758A (en) * 1964-09-25 1967-10-17 Mobil Oil Corp Electrochemical preparation of aromatic esters
FR2351932A1 (en) * 1976-05-21 1977-12-16 Rhone Poulenc Ind Anodic oxidn. of toluene and xylene(s) - to produce methyl benzyl ether(s) and methoxy benzaldehyde(s)
FR2376226A1 (en) * 1976-12-28 1978-07-28 Basf Ag ELECTROCHEMICAL PREPARATION OF AROMATIC OR HETEROCYCLIC-AROMATIC ESTERS
EP0011712A2 (en) * 1978-11-08 1980-06-11 BASF Aktiengesellschaft Preparation of benzaldehyde dialkyl acetals substituted in the 4-position

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4148696A (en) * 1978-03-20 1979-04-10 Uop Inc. Electrochemical oxidation of activated alkyl aromatic compounds

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3347758A (en) * 1964-09-25 1967-10-17 Mobil Oil Corp Electrochemical preparation of aromatic esters
FR2351932A1 (en) * 1976-05-21 1977-12-16 Rhone Poulenc Ind Anodic oxidn. of toluene and xylene(s) - to produce methyl benzyl ether(s) and methoxy benzaldehyde(s)
FR2376226A1 (en) * 1976-12-28 1978-07-28 Basf Ag ELECTROCHEMICAL PREPARATION OF AROMATIC OR HETEROCYCLIC-AROMATIC ESTERS
EP0011712A2 (en) * 1978-11-08 1980-06-11 BASF Aktiengesellschaft Preparation of benzaldehyde dialkyl acetals substituted in the 4-position

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
CHEMICAL ABSTRACTS, Band 71, 13. Oktober 1969, Seite 287, Nr. 70336d, Columbus, Ohio, US; & JP-B-43 014683 (TOYO RAYON CO., LTD.) 21-06-1968 *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0212509A1 (en) * 1985-08-14 1987-03-04 BASF Aktiengesellschaft Process for manufacturing benzoic-acid orthoesters, and compounds of this class
US4699698A (en) * 1985-08-14 1987-10-13 Basf Aktiengesellschaft Preparation of benzoic acid ortho-esters and novel compounds of this type
WO2002020446A1 (en) * 2000-09-06 2002-03-14 Basf Aktiengesellschaft Method for producing orthocarbonic acid trialkyl esters
JP2004508463A (en) * 2000-09-06 2004-03-18 ビーエーエスエフ　アクチェンゲゼルシャフト Method for producing trialkyl orthocarboxylate
US7192512B2 (en) 2000-09-06 2007-03-20 Basf Aktiengesellschaft Method for producing orthocarbonic acid trialkyl esters

Also Published As

Publication number Publication date
US4612092A (en) 1986-09-16
DE3560320D1 (en) 1987-08-13
EP0179289B1 (en) 1987-07-08
DE3435388A1 (en) 1986-04-03

Similar Documents

Publication Publication Date Title
DE2848397C2 (en) Electrochemical production of benzaldehyde dialkyl acetals substituted in the 4-position
EP1348043B1 (en) Method for producing alcoxylated carbonyl compounds by an anodic oxidation method using a cathodic coupled reaction for organic synthesis
EP0179289B1 (en) Method for producing aromatic carboxylic esters
EP0072914B1 (en) Process for the production of alkyl-substituted benzaldehydes
EP0129795B1 (en) Process for manufacturing benzaldehyde dialkylacetals
EP0287954B1 (en) Benzaldehyde dialkyl acetals, their preparation and use
EP0012942B1 (en) Electrolytic process for producing benzaldehydes
EP0339523B1 (en) Process for manufacturing hydroxycarboxylic-acid esters
EP0029995B1 (en) Process for the preparation of 4-tert.-butylbenzaldehyde
DE4327361A1 (en) Process for the preparation of benzaldehyde dialkyl acetals
DE3529074A1 (en) METHOD FOR THE PRODUCTION OF BENZOESAEUREORTHOESTERS AND COMPOUNDS OF THIS CLASS
DE3142626A1 (en) ELECTROCHEMICAL METHOD FOR PRODUCING 2,5-DIALKOXY-2,5-DIHYDROFURANES
EP0237762B1 (en) Process for the preparation of pyrazoles
EP0308744B1 (en) Process for the preparation of imidazolidinones and oxazolidinones
EP0283807B1 (en) Process for the preparation of methoxyacetaldehyde dialkyl acetals
EP0393668B1 (en) Method of preparation of benzaldehyde dialkyl acetals and new benzaldehyde dialkyl acetals
EP0152801B1 (en) Process for manufacturing benzaldehyde dialkylacetals
EP0384315B1 (en) Process for manufacturing lactones
EP0339521B1 (en) Process for manufacturing tetralin derivatives, and tetralin derivatives
EP0292889B1 (en) Benzaldehyde derivatives, their preparation and use
EP0513577B1 (en) Method for the preparation of 1-alkoxyisochromans
DE3605451A1 (en) BENZALDEHYD DIALKYL ACETAL
DE3619656A1 (en) NEW 2,6-DIMETHYL-P-BENZOCHINONE TETRAALKYLKETALES AND THEIR PRODUCTION
DE3939285A1 (en) 2-TERT.-BUTYL-P-BENZOCHINONETRAALKYLKETAL AND THEIR PRODUCTION

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): CH DE FR GB IT LI NL

17P Request for examination filed

Effective date: 19860313

17Q First examination report despatched

Effective date: 19861205

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): CH DE FR GB IT LI NL

ITF It: translation for a ep patent filed

Owner name: ING. C. GREGORJ S.P.A.

REF Corresponds to:

Ref document number: 3560320

Country of ref document: DE

Date of ref document: 19870813

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 19870930

Year of fee payment: 3

ET Fr: translation filed
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Effective date: 19890930

Ref country code: CH

Effective date: 19890930

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Effective date: 19900401

NLV4 Nl: lapsed or anulled due to non-payment of the annual fee
REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 19930804

Year of fee payment: 9

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 19930916

Year of fee payment: 9

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 19930920

Year of fee payment: 9

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Effective date: 19940924

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 19940924

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Effective date: 19950531

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Effective date: 19950601

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST