CA1278301C - Process for preparing 2,3-dichlorothiophene - Google Patents
Process for preparing 2,3-dichlorothiopheneInfo
- Publication number
- CA1278301C CA1278301C CA000520752A CA520752A CA1278301C CA 1278301 C CA1278301 C CA 1278301C CA 000520752 A CA000520752 A CA 000520752A CA 520752 A CA520752 A CA 520752A CA 1278301 C CA1278301 C CA 1278301C
- Authority
- CA
- Canada
- Prior art keywords
- chlorothiophene
- dichlorothiophene
- isomerization
- chlorination
- preparing
- 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.)
- Expired - Fee Related
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D333/00—Heterocyclic compounds containing five-membered rings having one sulfur atom as the only ring hetero atom
- C07D333/02—Heterocyclic compounds containing five-membered rings having one sulfur atom as the only ring hetero atom not condensed with other rings
- C07D333/04—Heterocyclic compounds containing five-membered rings having one sulfur atom as the only ring hetero atom not condensed with other rings not substituted on the ring sulphur atom
- C07D333/26—Heterocyclic compounds containing five-membered rings having one sulfur atom as the only ring hetero atom not condensed with other rings not substituted on the ring sulphur atom with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
- C07D333/28—Halogen atoms
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
- Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE:
Process for preparing 2,3-dichlorothiophene The invention relates to the preparation of 2,3-dichloro-thiophene by chlorinating 3-chlorothiophene or by isomer-izing 2-chlorothiophene to 3-chlorothiophene and subse-quently chlorinating the latter. The isomerization is generally carried out by means of a zeolite catalyst.
Process for preparing 2,3-dichlorothiophene The invention relates to the preparation of 2,3-dichloro-thiophene by chlorinating 3-chlorothiophene or by isomer-izing 2-chlorothiophene to 3-chlorothiophene and subse-quently chlorinating the latter. The isomerization is generally carried out by means of a zeolite catalyst.
Description
~2~3~
23~21-4291 The present invention relates to a pro-ess ~or preparing 2,3-dichlorothiophene.
Halogenated thiophenes are use~ul intermediates for preparing pharma~euticals, plant protection agents and dyes [Manufacturing Chemist and Aerosol News, May 1978]. For instance, derivatives of 2,3-dihalogenothiophenes find utility among others as ~-blockers or as antiparasitic substances ~chemi~er-Zeitung 103 (5), 161 to 172 (1979)].
Any wider use of the 2,3-dihalogenothiophenes has hitherto been prevented by their poor accessibility.
For instance, 2 r 3-dichlorothiophene can be obtained in a ratio of 1:1 toyether with 2,4-dichlorothiophene by pyrolyzing the optically inactive 2,3,4,5-tetrachlorotetrahydrothiophene produced in low selectivity on chlorinating thiophene to 2-chlorothiophene [Coonradt et al., J. Am. Chem. Soc. 70, 2564 (19~8)].
The conversion of the similarly costly starting materials 2,3-dibromothiophene or 2,3-diiodothiophene with CuCl to 2,3-dichlorothiophene is more of scientific interest [~onde, S. et al., Synthesis 6, 412 (1976)].
It has now been found that 2,3-dichlorothiophene is obtained in hlgh yields by isomerizing 2-chlorothiophene and sub-sequently chlorinating the resultin~ 3-chlorothiophene.
The invention therefore provides a process for preparing 2,3-dichlorothiophene, which comprises isomerizing 2-chlorothio-phene with a zeolite as catalyst to 3-chlorothiophene and chlorin-ating the latter to yive 2,3-dichlorothiophene. The invention further provides a process for preparing ~7~3~'~
2,3-dichlorothiophene, which comprises chlor;nating 3-chlorothiophene.
It is extremely surprising that the chlorination of 3-chlorothiophene proceeds with virtually exclus;ve forma-tion of 2,3-dichlorothiophene and therefore permits indus-trial manufacture thereof.
The isomerization of 2-chLorothiophene to 3-chlorothio-phene has already been described in German Patent Appli-cation P 34 19 555.6. In said process, 2-chlorothiophene is first brought into contact, alone or together with an organic diluent, with an isomerization catalyst. To re-duce the inlet partial pressure or to improve the service life, the feed can have additionally added to it inorganic gases such as N2, argon or H2.
The organic diluent used is in general benzene, alkyl-benzenes or mono- or poly-halogenated b~nzenes or toluenes~
The molar ratio of ~he diluent to the 2-halogenothiophene used is in general 1:1 to 5:1 ~mol/mol)A
Suitable isomerization catalysts are in general natural and synthetic zeolites, preferably synthetic zeolites of the faujasite type, such as zeolite X (US Patent 2,882,244) and zeolite Y (US Patent 3,130,007~, of the mordenite type and also pentasil type, such as ZSM-5 (US Patent 3,702,886), ZSM-11 (US Patent 3,709,979), ZSM-8 (British Patent 1,334,243), ZSM-12 (US Patent 3,832,449), ZSM-20 (US Pat-ent 3,972,983), ZSM-21 (US Patent 4,046,859), ZSM-23 (US
Patent 4,076,842), ZSM-35 (US Patent 4,016~245)~ ZSM-38 (US Patent 4,046,859), ~SM-48 (EP-A1-0,023,089). Particu-lar preference is given to zeolites of the pentasil type.
The S;/Al ratio of the pentasiLs is preferably 20 to 200, that of the mordenites preferably 5 to 100.
Su;table zeolites for the process according to the inven-tion also include those which are structurally anaLogous to the abovementioned zeolites but ;n which aluminum or ~27B~i silicon has been repla~ed at least partly by other lattice atoms, such as boron, iron, gallium, germanium, titanium or zirconium.
In ~he process according to the invention, the zeolites are preferably in their acid form. The preparation of the acid form is effected by ion exchange with mono-~ di- or tri-valent cations, preferably with NH4, H~, Be2~, Mg2 , Ca2 , La3t or rare earth cations and also with combinations of these cations. The zeoLites thus modified are additionally 1D preferably activated ;n conventional manner by calcining, which constitutes a fur~her kind of modification. The calcining is preferably carried out at 350 to 700C. For better stabilization, it is advantageous to carry out the calcining in the presence of steam, ammonia or mixtures thereof at temperatures between 600 and 900C.
The zeolites mentioned are brought for industrial use into the extrudate form by means of binders~ the selectivity and the operating life being affected by the choice of binder.
SuitabLe binders are in par~icular the oxides, hydroxides or hydroxychlorides of aluminum and the ox;des of sili-con, the o~ides of titanium and zirconium and also clay materials.
The isomerization can be carried out not only in the gas phase but also ;n the liquid phase; other conceivable methods are for example a trickle phase with employment of a higher pressure~
If the isomerization according to the invention is car-ried out ;n the gas phase with a fixed-bed catalyst, the reaction temperatures are in general 150-550L, preferably 180-450C, and the pressures 1 to 20 bar, preferably 2 to 10 bar.
~hen working in the Liquid phase, the isomerization is carried out at temperatures of 150 to 350C~ preferably 200 to 300C, and at pressures of 4 to 100 bar, ~L~
- ~ - 23221-~291 preferabl~ lO to 50 bar.
The loading (WHSV = weight hourly space velocity h-l) should be preferably between 0.1 and lO h-l. If regeneration of the catalyst is necessary, this can be effected by controlled burnoff with oxygen-containing gases.
The isomerization proceeds very selectively and, depend-ing on process conditions, such as, for example, temperature and residence time and also depending on the type of zeolite, gives high proportions of 3-chlorothiophene. The mixture of isomers obtained comprises 85 to 90~ by weight of 3-chlorothiophene, 5 to 103 by weight of 2-chlorothiophene and small amounts of -thiophene.
This mixture of isomers can be directly used in the chlorination step of the process according to the invention (if desired after distillative removal of the diluent). However, it is also pos-sible first to remove the 2-chlorothiophene before chlorinating.
The chlorination is carried out with gaseous chlorine in customary cast-iron or steel stirred kettles which are equipped with jacket and/or coil cooling, chlorine inlet, offgas, filling and emptying pipes. Even trickle phase reactors in which 3-chlorothiophene is introduced at the top and gaseous chlorine is introduced in the middle portion of the reactor are most suitable for the continuous preparation of 2,3-dichlorothiophene.
The chlorine:3-chlorothiophene ratio, expressed in mol per mol, should be 0.3:1 to l.l:l, preferably 0.7:1 to 0.95:1 (mol/mol).
The chlorination can be carried out without additional solvent.
~.
~27B301 - 4a 23221~4291 The chlorina-tion temperatures are customarily be-tween 40 and 120C, preferably between 60 and 100C.
The product mixture which is obtained on chlorinating the abovementioned mixture of 3- and 2-chlorothiophene and 3~
which essentially comprises 2,3-d;chlorothiophene and small amounts of 2,5-dichlorothiophene and also residues of 2-chloroth;ophene and 3-chloroth;ophene ;s worked up by d;stillation.
s In the batchwise workup~ firs~ the 2-/3-chlorothiophene boiling at 128C and 135C respectively are taken off as the distillation peak and then the 2,5- and 2,3-dichloro-thiophene isomers boiling at 162C and 172C are sepa-rated off. If the 2,5-chlorothiophene obtained as a twin product, is not wanted, the isomerization stage can be follo~ed with a more complex distillation in which 2-chlorothiophene is separated from 3-chlorothiophene. The subsequent chlorination of 3-chlorothiophene gives a 2,3-d;chlorothiophene yield of over 80%, based on 2-15 ~chlorothiophene.
The invention is illustrated by the non-limiting examples below.
Example 1 (isomerization and subsequent chlorination of the mixture of isomers):
A ZSM-5 zeoli~e synthesized as described in US Patent 3,702,886 was first thermally pretreated at 550C for 12 hours and then mixed in a ratio of 2:1 with aluminum oxide9 pasted up with a dilute m;neral acid and processed to form 1~4 mm thick extrudates~ The catalyst extrudates obtained were subsequently dried at 130C and then calcined at 600C for 2 hours. After this treatment the extrudates were repeatedly brought into contact with a 10% strength ammonium sulfate solut;on, and the sod;um ;ons present from the synthesis exhaustively replaced for NH4 ions. A
further thermal treatment of these extrudates at 600C ga~e the acid H-for0 of the ZSM 5 zeolite.
To isomerize the 2-chlorothiophene, a fixed-bed reactor of 20 mm in internal diameter and 1000 mm in length was loaded with 200 ml of the catalyst described above and, at atmospheric pressure and 300C, was charged with ~27~
- h -400 ~l/h of a 1 iquid mi~ture composed of 2-chlorothio-phene and 1,2,4-trichlorobenzene. AFter 17.0 mol of 2-chloroth;ophene had been put through, the reaction was discontinued after 15 hours, and the condensed reactor d;schar~e was worked up. To this end, the mixture of chloroth;ophene isomers was separated from 1,2,4-chloro-thiobenzene by distillation and held available for the chlorination.
The apparatus used for the chlorination comprised a 4-liter three-necked flask with st;rrer, gas inlet tube, internal thermometer and reflux condenser. The hydrogen chlor;de leav;ng through the reflux condenser ~as absorbed by water or sod;um hydrox;de solut;on. The flask was heated by means of an oil bath. To perform ~he chlor;nation, 1900 9 of the mixture of chlorothiophene isomers obtained from the abovementioned distillative separation was intro-duced first into the flask ~ithout solvent.
After the flask content had been temperature-controled to 90C, the chlorination was started by a metering in chlorine at a rate of 2 mol/h. In the course of the chlor;nat;on, the ;nternal flask temperature rose from 90 to 105C. After 16 mol of chlor;ne had been passed in, the reaction ~as terminated and the ~ixture of ~hlorothio-phene isomers was dist;lled. A forerun composed of 2-/
3-chloroth;ophene was ;n;tially taken off at the top of a 60-plate packed column. This ~as followed, after a short ;nterrun, by 2,5-dichlorothiophene with small amounts of 2,3-d;chlorothiophene. The d;stillat;on, which pro-ceeds w;th deplet;on of 2,3-d;chlorothiophene, was ter-m;nated on reach;ng a 2,3-chloroth;ophene content in the column bottom product of about 98%.
The 1680 9 of 2,3-dichlorothiophene obtained in th;s dis-tillat;on correspond to a 2-chloroth;ophene-based y;eld of 65%.
Unconverted 2- and 3-chloroth;ophene were recycled for renewed chlorination or~ ;n the case of the former, for ~27~
renewed isomerization~ The 2,5-dichlorothiophene fraction contaminated with 2,3-dichlorothiophene W3S ~orked up separately to give 205-dichlorothiophene.
Example 2 (isomerization and subsequent chlorination of the isolated 3-chlorothiophene):
~y using the apparatus described in Example 1, 2-chloro-thiophene was isomerized to produce 6.3 kg of mixed chloro-thiophene isomers contaminated with a little thiophene.
The isomerization product mixture composed of 85% byweight of 3-chlorothiophene, 13% by weight of 2-chlorothio~
phene and 2% by weight of thiophene was fractionated in an 80-plate packed column under atmospheric pressure into 3.4 kg of 99% pure 3-chlorothiophene and 2.8S kg of a m;xture of 2-/3-chlorothiophene isomers~ The 3-chloro-thiophene fraction obtained in the fract;onation was chlorinated at 90C in the absence of a solvent in the app-aratus described in Example 1 with a metering rateof 3 mol/h. Table 1 shows the relationship between 3-chlorothiophene conversion and 2,3-dichlorothiophene selec-tivity, determined by gas chromatography analysis, which ;ndicates the remarkably high selectivity of the chlorina-tion o~ 3-chlorothiophene.
Conversion of Selectivity to 3-chlorothiophene (%~ _ _ 2,3-dichlorothiophene ~0 Table 1 : chlorination of 3-chlorothiophene The workup carried out after the chlorination had been terminated gave 3530 9 of 2,3-dichlorothiophene twhich ~2~7~.3~L
corresponds to an 80% yield) and 340 9 of 3-chlorothio-phene ~hich can be used for renewed chlorination.
23~21-4291 The present invention relates to a pro-ess ~or preparing 2,3-dichlorothiophene.
Halogenated thiophenes are use~ul intermediates for preparing pharma~euticals, plant protection agents and dyes [Manufacturing Chemist and Aerosol News, May 1978]. For instance, derivatives of 2,3-dihalogenothiophenes find utility among others as ~-blockers or as antiparasitic substances ~chemi~er-Zeitung 103 (5), 161 to 172 (1979)].
Any wider use of the 2,3-dihalogenothiophenes has hitherto been prevented by their poor accessibility.
For instance, 2 r 3-dichlorothiophene can be obtained in a ratio of 1:1 toyether with 2,4-dichlorothiophene by pyrolyzing the optically inactive 2,3,4,5-tetrachlorotetrahydrothiophene produced in low selectivity on chlorinating thiophene to 2-chlorothiophene [Coonradt et al., J. Am. Chem. Soc. 70, 2564 (19~8)].
The conversion of the similarly costly starting materials 2,3-dibromothiophene or 2,3-diiodothiophene with CuCl to 2,3-dichlorothiophene is more of scientific interest [~onde, S. et al., Synthesis 6, 412 (1976)].
It has now been found that 2,3-dichlorothiophene is obtained in hlgh yields by isomerizing 2-chlorothiophene and sub-sequently chlorinating the resultin~ 3-chlorothiophene.
The invention therefore provides a process for preparing 2,3-dichlorothiophene, which comprises isomerizing 2-chlorothio-phene with a zeolite as catalyst to 3-chlorothiophene and chlorin-ating the latter to yive 2,3-dichlorothiophene. The invention further provides a process for preparing ~7~3~'~
2,3-dichlorothiophene, which comprises chlor;nating 3-chlorothiophene.
It is extremely surprising that the chlorination of 3-chlorothiophene proceeds with virtually exclus;ve forma-tion of 2,3-dichlorothiophene and therefore permits indus-trial manufacture thereof.
The isomerization of 2-chLorothiophene to 3-chlorothio-phene has already been described in German Patent Appli-cation P 34 19 555.6. In said process, 2-chlorothiophene is first brought into contact, alone or together with an organic diluent, with an isomerization catalyst. To re-duce the inlet partial pressure or to improve the service life, the feed can have additionally added to it inorganic gases such as N2, argon or H2.
The organic diluent used is in general benzene, alkyl-benzenes or mono- or poly-halogenated b~nzenes or toluenes~
The molar ratio of ~he diluent to the 2-halogenothiophene used is in general 1:1 to 5:1 ~mol/mol)A
Suitable isomerization catalysts are in general natural and synthetic zeolites, preferably synthetic zeolites of the faujasite type, such as zeolite X (US Patent 2,882,244) and zeolite Y (US Patent 3,130,007~, of the mordenite type and also pentasil type, such as ZSM-5 (US Patent 3,702,886), ZSM-11 (US Patent 3,709,979), ZSM-8 (British Patent 1,334,243), ZSM-12 (US Patent 3,832,449), ZSM-20 (US Pat-ent 3,972,983), ZSM-21 (US Patent 4,046,859), ZSM-23 (US
Patent 4,076,842), ZSM-35 (US Patent 4,016~245)~ ZSM-38 (US Patent 4,046,859), ~SM-48 (EP-A1-0,023,089). Particu-lar preference is given to zeolites of the pentasil type.
The S;/Al ratio of the pentasiLs is preferably 20 to 200, that of the mordenites preferably 5 to 100.
Su;table zeolites for the process according to the inven-tion also include those which are structurally anaLogous to the abovementioned zeolites but ;n which aluminum or ~27B~i silicon has been repla~ed at least partly by other lattice atoms, such as boron, iron, gallium, germanium, titanium or zirconium.
In ~he process according to the invention, the zeolites are preferably in their acid form. The preparation of the acid form is effected by ion exchange with mono-~ di- or tri-valent cations, preferably with NH4, H~, Be2~, Mg2 , Ca2 , La3t or rare earth cations and also with combinations of these cations. The zeoLites thus modified are additionally 1D preferably activated ;n conventional manner by calcining, which constitutes a fur~her kind of modification. The calcining is preferably carried out at 350 to 700C. For better stabilization, it is advantageous to carry out the calcining in the presence of steam, ammonia or mixtures thereof at temperatures between 600 and 900C.
The zeolites mentioned are brought for industrial use into the extrudate form by means of binders~ the selectivity and the operating life being affected by the choice of binder.
SuitabLe binders are in par~icular the oxides, hydroxides or hydroxychlorides of aluminum and the ox;des of sili-con, the o~ides of titanium and zirconium and also clay materials.
The isomerization can be carried out not only in the gas phase but also ;n the liquid phase; other conceivable methods are for example a trickle phase with employment of a higher pressure~
If the isomerization according to the invention is car-ried out ;n the gas phase with a fixed-bed catalyst, the reaction temperatures are in general 150-550L, preferably 180-450C, and the pressures 1 to 20 bar, preferably 2 to 10 bar.
~hen working in the Liquid phase, the isomerization is carried out at temperatures of 150 to 350C~ preferably 200 to 300C, and at pressures of 4 to 100 bar, ~L~
- ~ - 23221-~291 preferabl~ lO to 50 bar.
The loading (WHSV = weight hourly space velocity h-l) should be preferably between 0.1 and lO h-l. If regeneration of the catalyst is necessary, this can be effected by controlled burnoff with oxygen-containing gases.
The isomerization proceeds very selectively and, depend-ing on process conditions, such as, for example, temperature and residence time and also depending on the type of zeolite, gives high proportions of 3-chlorothiophene. The mixture of isomers obtained comprises 85 to 90~ by weight of 3-chlorothiophene, 5 to 103 by weight of 2-chlorothiophene and small amounts of -thiophene.
This mixture of isomers can be directly used in the chlorination step of the process according to the invention (if desired after distillative removal of the diluent). However, it is also pos-sible first to remove the 2-chlorothiophene before chlorinating.
The chlorination is carried out with gaseous chlorine in customary cast-iron or steel stirred kettles which are equipped with jacket and/or coil cooling, chlorine inlet, offgas, filling and emptying pipes. Even trickle phase reactors in which 3-chlorothiophene is introduced at the top and gaseous chlorine is introduced in the middle portion of the reactor are most suitable for the continuous preparation of 2,3-dichlorothiophene.
The chlorine:3-chlorothiophene ratio, expressed in mol per mol, should be 0.3:1 to l.l:l, preferably 0.7:1 to 0.95:1 (mol/mol).
The chlorination can be carried out without additional solvent.
~.
~27B301 - 4a 23221~4291 The chlorina-tion temperatures are customarily be-tween 40 and 120C, preferably between 60 and 100C.
The product mixture which is obtained on chlorinating the abovementioned mixture of 3- and 2-chlorothiophene and 3~
which essentially comprises 2,3-d;chlorothiophene and small amounts of 2,5-dichlorothiophene and also residues of 2-chloroth;ophene and 3-chloroth;ophene ;s worked up by d;stillation.
s In the batchwise workup~ firs~ the 2-/3-chlorothiophene boiling at 128C and 135C respectively are taken off as the distillation peak and then the 2,5- and 2,3-dichloro-thiophene isomers boiling at 162C and 172C are sepa-rated off. If the 2,5-chlorothiophene obtained as a twin product, is not wanted, the isomerization stage can be follo~ed with a more complex distillation in which 2-chlorothiophene is separated from 3-chlorothiophene. The subsequent chlorination of 3-chlorothiophene gives a 2,3-d;chlorothiophene yield of over 80%, based on 2-15 ~chlorothiophene.
The invention is illustrated by the non-limiting examples below.
Example 1 (isomerization and subsequent chlorination of the mixture of isomers):
A ZSM-5 zeoli~e synthesized as described in US Patent 3,702,886 was first thermally pretreated at 550C for 12 hours and then mixed in a ratio of 2:1 with aluminum oxide9 pasted up with a dilute m;neral acid and processed to form 1~4 mm thick extrudates~ The catalyst extrudates obtained were subsequently dried at 130C and then calcined at 600C for 2 hours. After this treatment the extrudates were repeatedly brought into contact with a 10% strength ammonium sulfate solut;on, and the sod;um ;ons present from the synthesis exhaustively replaced for NH4 ions. A
further thermal treatment of these extrudates at 600C ga~e the acid H-for0 of the ZSM 5 zeolite.
To isomerize the 2-chlorothiophene, a fixed-bed reactor of 20 mm in internal diameter and 1000 mm in length was loaded with 200 ml of the catalyst described above and, at atmospheric pressure and 300C, was charged with ~27~
- h -400 ~l/h of a 1 iquid mi~ture composed of 2-chlorothio-phene and 1,2,4-trichlorobenzene. AFter 17.0 mol of 2-chloroth;ophene had been put through, the reaction was discontinued after 15 hours, and the condensed reactor d;schar~e was worked up. To this end, the mixture of chloroth;ophene isomers was separated from 1,2,4-chloro-thiobenzene by distillation and held available for the chlorination.
The apparatus used for the chlorination comprised a 4-liter three-necked flask with st;rrer, gas inlet tube, internal thermometer and reflux condenser. The hydrogen chlor;de leav;ng through the reflux condenser ~as absorbed by water or sod;um hydrox;de solut;on. The flask was heated by means of an oil bath. To perform ~he chlor;nation, 1900 9 of the mixture of chlorothiophene isomers obtained from the abovementioned distillative separation was intro-duced first into the flask ~ithout solvent.
After the flask content had been temperature-controled to 90C, the chlorination was started by a metering in chlorine at a rate of 2 mol/h. In the course of the chlor;nat;on, the ;nternal flask temperature rose from 90 to 105C. After 16 mol of chlor;ne had been passed in, the reaction ~as terminated and the ~ixture of ~hlorothio-phene isomers was dist;lled. A forerun composed of 2-/
3-chloroth;ophene was ;n;tially taken off at the top of a 60-plate packed column. This ~as followed, after a short ;nterrun, by 2,5-dichlorothiophene with small amounts of 2,3-d;chlorothiophene. The d;stillat;on, which pro-ceeds w;th deplet;on of 2,3-d;chlorothiophene, was ter-m;nated on reach;ng a 2,3-chloroth;ophene content in the column bottom product of about 98%.
The 1680 9 of 2,3-dichlorothiophene obtained in th;s dis-tillat;on correspond to a 2-chloroth;ophene-based y;eld of 65%.
Unconverted 2- and 3-chloroth;ophene were recycled for renewed chlorination or~ ;n the case of the former, for ~27~
renewed isomerization~ The 2,5-dichlorothiophene fraction contaminated with 2,3-dichlorothiophene W3S ~orked up separately to give 205-dichlorothiophene.
Example 2 (isomerization and subsequent chlorination of the isolated 3-chlorothiophene):
~y using the apparatus described in Example 1, 2-chloro-thiophene was isomerized to produce 6.3 kg of mixed chloro-thiophene isomers contaminated with a little thiophene.
The isomerization product mixture composed of 85% byweight of 3-chlorothiophene, 13% by weight of 2-chlorothio~
phene and 2% by weight of thiophene was fractionated in an 80-plate packed column under atmospheric pressure into 3.4 kg of 99% pure 3-chlorothiophene and 2.8S kg of a m;xture of 2-/3-chlorothiophene isomers~ The 3-chloro-thiophene fraction obtained in the fract;onation was chlorinated at 90C in the absence of a solvent in the app-aratus described in Example 1 with a metering rateof 3 mol/h. Table 1 shows the relationship between 3-chlorothiophene conversion and 2,3-dichlorothiophene selec-tivity, determined by gas chromatography analysis, which ;ndicates the remarkably high selectivity of the chlorina-tion o~ 3-chlorothiophene.
Conversion of Selectivity to 3-chlorothiophene (%~ _ _ 2,3-dichlorothiophene ~0 Table 1 : chlorination of 3-chlorothiophene The workup carried out after the chlorination had been terminated gave 3530 9 of 2,3-dichlorothiophene twhich ~2~7~.3~L
corresponds to an 80% yield) and 340 9 of 3-chlorothio-phene ~hich can be used for renewed chlorination.
Claims (5)
1. A process for preparing 2,3-dichlorothiophene, which comprises isomerizing 2-chlorothiophene with a zeolite as catalyst to 3-chlorothiophene and subsequently chlorinating this 3-chlorothiophene to give 2,3-dichlorothiophene.
2. The process as claimed in claim 1, wherein the zeolite catalyst used is an acid zeolite.
3. The process as claimed in claim 1, wherein the zeolite catalyst used is a zeolite of the pentasil type.
4. The process as claimed in claim 1, wherein the zeolite catalyst used is an acid pentasil.
5. A process for preparing 2,3-dichlorothiophene, which comprises chlorinating 3-chlorothiophene.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19853537288 DE3537288A1 (en) | 1985-10-19 | 1985-10-19 | METHOD FOR PRODUCING 2.3 DICHLORTHIOPHEN |
| DEP3537288.5 | 1985-10-19 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1278301C true CA1278301C (en) | 1990-12-27 |
Family
ID=6283988
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000520752A Expired - Fee Related CA1278301C (en) | 1985-10-19 | 1986-10-17 | Process for preparing 2,3-dichlorothiophene |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP0219797B1 (en) |
| JP (1) | JPS6299373A (en) |
| AT (1) | ATE42552T1 (en) |
| BR (1) | BR8605081A (en) |
| CA (1) | CA1278301C (en) |
| DE (2) | DE3537288A1 (en) |
| HU (1) | HU199137B (en) |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1768209B1 (en) * | 1968-04-13 | 1972-01-05 | Consortium Elektrochem Ind | Process for the reductive exchange of chlorine for hydrogen on the thiophene ring |
| DE3419555A1 (en) * | 1984-05-25 | 1985-11-28 | Hoechst Ag, 6230 Frankfurt | METHOD FOR ISOMERIZING HALOGENED THIOPHENES |
| EP0182111B1 (en) * | 1984-10-20 | 1989-09-20 | BASF Aktiengesellschaft | Process for the preparation of perhalogenated compounds |
-
1985
- 1985-10-19 DE DE19853537288 patent/DE3537288A1/en not_active Withdrawn
-
1986
- 1986-10-07 HU HU864330A patent/HU199137B/en unknown
- 1986-10-14 AT AT86114182T patent/ATE42552T1/en not_active IP Right Cessation
- 1986-10-14 DE DE8686114182T patent/DE3663027D1/en not_active Expired
- 1986-10-14 EP EP86114182A patent/EP0219797B1/en not_active Expired
- 1986-10-17 JP JP61245626A patent/JPS6299373A/en active Pending
- 1986-10-17 CA CA000520752A patent/CA1278301C/en not_active Expired - Fee Related
- 1986-10-17 BR BR8605081A patent/BR8605081A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| EP0219797B1 (en) | 1989-04-26 |
| DE3663027D1 (en) | 1989-06-01 |
| HU199137B (en) | 1990-01-29 |
| BR8605081A (en) | 1987-07-21 |
| DE3537288A1 (en) | 1987-04-23 |
| ATE42552T1 (en) | 1989-05-15 |
| JPS6299373A (en) | 1987-05-08 |
| HUT42081A (en) | 1987-06-29 |
| EP0219797A1 (en) | 1987-04-29 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA1155142A (en) | Preparation of 2-phenylalkanes | |
| Tiecco et al. | Ring-closure reactions of alkenyl oximes induced by persulfate anion oxidation of diphenyl diselenide. Formation of 1, 2-oxazines and cyclic nitrones | |
| JP2996727B2 (en) | Method for producing tertiary butylamine | |
| US5292980A (en) | Base-catalyzed reactions using zeolite catalysts | |
| Nakano et al. | Rearrangement of (substituted benzyl) trimethylammonium ylides in a nonbasic medium: The improved Sommelet-Hauser rearrangement | |
| CA1278301C (en) | Process for preparing 2,3-dichlorothiophene | |
| HU204746B (en) | Process for isomerization of mono- or dichlorotoluenes | |
| IL115895A (en) | Process for preparing 5-chloro-2,3-dihydro-1h-inden-1-one | |
| Espeel et al. | Functional selectivity in Friedel-Crafts alkylations with polyfunctional reactants over acid zeolites | |
| US4604470A (en) | Process for the isomerization of halogenated thiophenes | |
| US4568777A (en) | Process for isomerizing monochlorophenols or dichlorophenols | |
| Jones et al. | Ortho-Substitution Rearrangement vs. Elimination Reaction of Certain Benzyl-Type Quaternary Ammonium Ions with Sodium Amide1 | |
| CA2049908A1 (en) | Process for the preparation of acylbenzenes | |
| US4783541A (en) | Process for isomerizing alkylthiophenes | |
| AU706529B2 (en) | Preparation of largely isomerically pure alpha-bisoximes | |
| US4306103A (en) | Process for the manufacture of 1,3,5-trichlorobenzene | |
| US4081489A (en) | Method of making 1,1,3-tri-substituted-3-phenylindane from α-substituted styrene compounds | |
| AU606202B2 (en) | Preparation of dien-1-ols, 9-hydroxydodec-10-enyl 1-tert-butyl ether and use thereof as an intermediate for synthesizing, 8,10-dodecadienol | |
| US4388461A (en) | Process for producing alpha-picoline | |
| Blatt et al. | Reaction of diarylcarbinols and diarylolefins with thionyl chloride: A synthesis of 3-arylbenzothiophens | |
| CA1144947A (en) | Process for the preparation of 3-bromo-4- fluorotoluene | |
| Al-hassan | Palladium-catalyzed cross-coupling of vinylalanes with aryl halides | |
| CA1144567A (en) | Co-production of 2-alkanones and phenols | |
| Schultz et al. | Asymmetric organic synthesis. Preparation and birch reduction-alkylation of 2-methyl-3, 4-dihydroisoquinolin-1-ones | |
| US5002639A (en) | Separation of ortho-, meta- and para-tolunitrile from ternary mixtures of the isomers |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |