CA1214472A - Process for recovering iodine compounds from the off- gas of carbonylation reactions - Google Patents
Process for recovering iodine compounds from the off- gas of carbonylation reactionsInfo
- Publication number
- CA1214472A CA1214472A CA000410911A CA410911A CA1214472A CA 1214472 A CA1214472 A CA 1214472A CA 000410911 A CA000410911 A CA 000410911A CA 410911 A CA410911 A CA 410911A CA 1214472 A CA1214472 A CA 1214472A
- Authority
- CA
- Canada
- Prior art keywords
- gas
- methyl acetate
- iodine compounds
- scrubbing
- compounds
- 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
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/54—Preparation of carboxylic acid anhydrides
- C07C51/56—Preparation of carboxylic acid anhydrides from organic acids, their salts, their esters or their halides, e.g. by carboxylation
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/54—Preparation of carboxylic acid anhydrides
- C07C51/573—Separation; Purification; Stabilisation; Use of additives
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/48—Separation; Purification; Stabilisation; Use of additives
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Treating Waste Gases (AREA)
- Catalysts (AREA)
- Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
Abstract
PROCESS FOR RECOVERING IODINE COMPOUNDS FROM THE OFF-GAS
OF CARBONYLATION REACTIONS
ABSTRACT OF THE DISCLOSURE:
The disclosure relates to a process for recovering iodine compounds from the off-gas originating from the reaction of methyl acetate and/or dimethylether with carbon monoxide and optionally hydrogen to give acetic anhydride and optionally ethylidene diacetate in the presence of a catalyst system consisting of carbonyl complexes of noble metals of group VIII of the Periodic System of the elements, an iodine compound, acetic acid, an organophosphorus or organonitrogen compound and, optionally, carbonyl-yielding compounds of common metals.
The disclosure provides more especially for off-gas which is removed together with liquid reaction products to be wholly or partially subjected to countercurrent scrubbing treat-ment with methyl acetate at temperatures of -40°C up to +20°C.
OF CARBONYLATION REACTIONS
ABSTRACT OF THE DISCLOSURE:
The disclosure relates to a process for recovering iodine compounds from the off-gas originating from the reaction of methyl acetate and/or dimethylether with carbon monoxide and optionally hydrogen to give acetic anhydride and optionally ethylidene diacetate in the presence of a catalyst system consisting of carbonyl complexes of noble metals of group VIII of the Periodic System of the elements, an iodine compound, acetic acid, an organophosphorus or organonitrogen compound and, optionally, carbonyl-yielding compounds of common metals.
The disclosure provides more especially for off-gas which is removed together with liquid reaction products to be wholly or partially subjected to countercurrent scrubbing treat-ment with methyl acetate at temperatures of -40°C up to +20°C.
Description
~2~7~
The present invention relates to a process for recovering iodine compounds from the off-gas originating from the reaction of methyl acetate and/or dimethylether with carbon monoxide and optionally hydrogen (carbonylation) to give acetic anhydride and optionally ethylidene di-acetate in the presence of a catalyst system consisting of carbonyl complexes of noble metals of group VIII o~ the Periodic System o~ the elements, an iodine compound, acetic acid, an organophosphorus compound or organonitrogen com-pound and optionally compo~nds of carbonyl-yielding common metals (cf. DE-A 24 50 965; 28 ~6 084; 29 39 839 and 29 41 232).
DE-A 30 28 9~4 describes a process ~or recovering halogen compounds ~rom o~f-gas originating from the ~
carbonylation o~ methyl acetate and/or dimethylether in the presence o~ a metal belonging to group VIII of the Periodic System o~ the elements and a halogen compound t the o~f-gas being contacted countercurrently in scrubb ing zone with a least one o~ the carbonylation reaction products, especially acetic acid, acetic a~hydride and ethylidene diacetate. The step of recycling the acetic a~hydride or ethylidene diacetate loaded with halogen compo~nd into the carbonylation zo~e result~ i~ the chemical equilibrium becoming af~ected and in the catalyst ef~iciency becoming considerably reduced.
It is therefore desirable to ha~e a process permitt-ing iodine compounds to be quantitatively recovered ~rom the off-gas originating from the carbonylation of methyl acetate and/or dimethylether, in the absence of the ad-verse e~fects described hereinabove.
Especially in continuous operation, a considerablepropor~ion of gaseous products is remo~ed together with the carbonylation products ~rom the reaction system. After separation into gas and liquid, the gas stream consisting predominantly of carbon monoxid0 is partially removed so as to avoid thç concentration of undesirable by-products, such as methane and carbon dioxide, and inert gases such as nitrogen in the gas phase. This off-gas stream contains ~ iodine compounds which are in the gas phase, consistently with their partial pressure. These iodine compounds would be lost if the off-gas removed were discarded~ Needless to say, this is not acceptable ~or reasons of economy. In addi-tion to this~ the iodine compounds present in the removed o~f-gas adversely af~ect its disposal, or the use of its constituents, especially methaneO It is there~ore an obli-gatory requirement that the iodine compounds should be re-covered from the gas stream ~or reeycling th~m into ~he carbonylation reactor, and ~or delivering decontaminated off-gas to the atmosphere. In the ga~ str~am, the iodine com-pounds are predominantly present ln the form of methyliodide together w~th ethyl iodide and acetyl iodide.
The present process comprises more particularly: sub-~ecting o~f-gas which is remo~ed together with the liquid reaction products, wholly or partially to countercurre~
~ 7 ~
scrubbing treatment with methyl acetate at temperatures of -40C up to +20C.
Preferred ~eaturcs of the prese~-t invention provide:
a) for the off-gas-to be scrubbed using methyl acetate in a quantity corresponding to the quantity of methyl ace-tate con~erted in the reaction zone;
b) ~or the of~-gas and methyl acetate to be used in the countercurrent scrubbing stage in a ratio by volume of (5 - 100) : 1, pre~erably (10 - 50) : 1;
c) for the methyl acetate which is used ~or scrubbing and loaded with iodine compounds, to be recycled into the-reactlon zone;
d) for the o~gas to contain carbon monoxide, carbon di-oxide, hydrogen, nitrogen, methane, methyl acetate ~5 and iodine compounds;
e) for a portion of the o~f~gas consisting predominantly of carbon monoxide and freed ~rom iodine compounds by countercurrent scrubbing treatment to be removed, the balance portion being recycled into the reaction zone.
The present process permits methyl acetate, i.e. a sub-stance participating ln the carbonylation reaction, to be used as the scrubbing l~uid and a~oids the adv~rse e~fects which would be liabl~ to affect the reaction upon the use of outside scrubbing liquids and ~heir introduction into the carbonylation æone.
The present invention not only enables the ~odine com-pounds to be quantltatively removed from the o~f-gas stream;
it also p~rmits methyl acetate ~tsel~ which is contained therein in proportions o~ 1 - 2 ~olume % to b~ extensively ~2~7~
remo~ed there~rom , The puri~ied o~-gas stream is found ~ust to contai~ traces of methyl acetate, consistently with its partial pressure, together with C0, H2 and CH4 and it can be used as a ~uel unless recycled into the carbonyla-tion zone because of its high C0-content.
The invention will now be described with reference to the accompanying drawlng.
Reaction product originating ~rom the carbonylation o~ methyl acetate and/or dimethylether with carbon mon-oxide and optlonally hydrogen in the presence of a cata-l~st system consisting of carbonyl complexes o~ noble me-tals o~ group VIII of the Periodic System o~ the elements (especially Rh, Ir, Pd9 Ru), methyl iodidet acetic acid, organophosphorus compounds or organonitrogen compounds and optionally carbonyl-yielding compounds of common me tals is taken from the carbonylation reactor and intro-duced through llne 1 into a separating s-tage 2. The pro-duct stream compr~sed o~ gaseous and liquid matter has a temperature o~ 0 180C, pre~erably 15 - 75C, Separat-ing stage 2 1s compri~ed of a separator and a column down-stream thereo~O It is ma~ntained under a pressure o~ 1 -3.5 bars. The products ~lowl~g through line 1 are separated in separating stage 2 into a llquid matter portion which is removed through line ~, and into a gaseous matter portion which has ~olatile iodine compound~ recoverable by the pre-sent process contained therein, consistentiwith their par-tial pr ssure. The gas flowing to the head o~ the separat-ing stage 2 pre~erably has a temperature o~ 15 - 30C. It is removed through line 4 and introduced wholly or partially ~ 7 ~
into the base portion o~ scrubbing column 5 which is pro-vided with trays, or packed, to improve the contact between gas and liquid. A portlon of the gaseous products is re-moved ~or scrubbing whilst the bulk is recycled through line 6 into the carbonylation reactor. The scrubbing column 5 is ~upplied overhead through line 7 with methyl acetate ha~ing a temperature o~ ~20 to -40C and the of~-gas flow-ing upwardly therein is scrubbed countercurrently there-with The ratio of gas ~olume to liquid volume is (5 - 100):
1, pre~erably (10 - 50) : 1, Scrubbing l~quid loaded with iodine compounds is recycled through line 8 into the carbo-nylation reactor. Iodine-free off-gas issues ~rom the scrubbing colum~ through line 9. In the e~ent of the entire gas stre~m being used ln the scrubbing stage, the bulk of the scrubbed o~f-gas is introduced through line 10 into the carbonylation reactor whilst a portion thereo~, which corres-ponds to the port~on use~ for scrub~ing as described abo~e, is removed from the system through line g.
The liter data in the ~ollowing Examples are based on standard condit~ons (0C and 1.013 bar).
Example 1 (Scrubbing ~otal gas stream~
6250 g/h reaction product was taken from the carbony lation reactor and introduced through line 1 ~nto the base portion oi separating ætage 2. It was maintained at a tem-perature o~ 60C and the product was separated into gaseous matter and liquid matter. 6150 g/h liquid matter was re-moved through line 3. 59 l/h o~f-gas composed approximately o~ (in volume %) 76.1 /0 C0s ~.1 % C02, 2 % methane9 1~5 %
hydrogen, 10.5 % nitrogen, 5.2 % methyl iodide and 1.6 %
~ 7~
methyl acetate was obtained at the head of separating stage
The present invention relates to a process for recovering iodine compounds from the off-gas originating from the reaction of methyl acetate and/or dimethylether with carbon monoxide and optionally hydrogen (carbonylation) to give acetic anhydride and optionally ethylidene di-acetate in the presence of a catalyst system consisting of carbonyl complexes of noble metals of group VIII o~ the Periodic System o~ the elements, an iodine compound, acetic acid, an organophosphorus compound or organonitrogen com-pound and optionally compo~nds of carbonyl-yielding common metals (cf. DE-A 24 50 965; 28 ~6 084; 29 39 839 and 29 41 232).
DE-A 30 28 9~4 describes a process ~or recovering halogen compounds ~rom o~f-gas originating from the ~
carbonylation o~ methyl acetate and/or dimethylether in the presence o~ a metal belonging to group VIII of the Periodic System o~ the elements and a halogen compound t the o~f-gas being contacted countercurrently in scrubb ing zone with a least one o~ the carbonylation reaction products, especially acetic acid, acetic a~hydride and ethylidene diacetate. The step of recycling the acetic a~hydride or ethylidene diacetate loaded with halogen compo~nd into the carbonylation zo~e result~ i~ the chemical equilibrium becoming af~ected and in the catalyst ef~iciency becoming considerably reduced.
It is therefore desirable to ha~e a process permitt-ing iodine compounds to be quantitatively recovered ~rom the off-gas originating from the carbonylation of methyl acetate and/or dimethylether, in the absence of the ad-verse e~fects described hereinabove.
Especially in continuous operation, a considerablepropor~ion of gaseous products is remo~ed together with the carbonylation products ~rom the reaction system. After separation into gas and liquid, the gas stream consisting predominantly of carbon monoxid0 is partially removed so as to avoid thç concentration of undesirable by-products, such as methane and carbon dioxide, and inert gases such as nitrogen in the gas phase. This off-gas stream contains ~ iodine compounds which are in the gas phase, consistently with their partial pressure. These iodine compounds would be lost if the off-gas removed were discarded~ Needless to say, this is not acceptable ~or reasons of economy. In addi-tion to this~ the iodine compounds present in the removed o~f-gas adversely af~ect its disposal, or the use of its constituents, especially methaneO It is there~ore an obli-gatory requirement that the iodine compounds should be re-covered from the gas stream ~or reeycling th~m into ~he carbonylation reactor, and ~or delivering decontaminated off-gas to the atmosphere. In the ga~ str~am, the iodine com-pounds are predominantly present ln the form of methyliodide together w~th ethyl iodide and acetyl iodide.
The present process comprises more particularly: sub-~ecting o~f-gas which is remo~ed together with the liquid reaction products, wholly or partially to countercurre~
~ 7 ~
scrubbing treatment with methyl acetate at temperatures of -40C up to +20C.
Preferred ~eaturcs of the prese~-t invention provide:
a) for the off-gas-to be scrubbed using methyl acetate in a quantity corresponding to the quantity of methyl ace-tate con~erted in the reaction zone;
b) ~or the of~-gas and methyl acetate to be used in the countercurrent scrubbing stage in a ratio by volume of (5 - 100) : 1, pre~erably (10 - 50) : 1;
c) for the methyl acetate which is used ~or scrubbing and loaded with iodine compounds, to be recycled into the-reactlon zone;
d) for the o~gas to contain carbon monoxide, carbon di-oxide, hydrogen, nitrogen, methane, methyl acetate ~5 and iodine compounds;
e) for a portion of the o~f~gas consisting predominantly of carbon monoxide and freed ~rom iodine compounds by countercurrent scrubbing treatment to be removed, the balance portion being recycled into the reaction zone.
The present process permits methyl acetate, i.e. a sub-stance participating ln the carbonylation reaction, to be used as the scrubbing l~uid and a~oids the adv~rse e~fects which would be liabl~ to affect the reaction upon the use of outside scrubbing liquids and ~heir introduction into the carbonylation æone.
The present invention not only enables the ~odine com-pounds to be quantltatively removed from the o~f-gas stream;
it also p~rmits methyl acetate ~tsel~ which is contained therein in proportions o~ 1 - 2 ~olume % to b~ extensively ~2~7~
remo~ed there~rom , The puri~ied o~-gas stream is found ~ust to contai~ traces of methyl acetate, consistently with its partial pressure, together with C0, H2 and CH4 and it can be used as a ~uel unless recycled into the carbonyla-tion zone because of its high C0-content.
The invention will now be described with reference to the accompanying drawlng.
Reaction product originating ~rom the carbonylation o~ methyl acetate and/or dimethylether with carbon mon-oxide and optlonally hydrogen in the presence of a cata-l~st system consisting of carbonyl complexes o~ noble me-tals o~ group VIII of the Periodic System o~ the elements (especially Rh, Ir, Pd9 Ru), methyl iodidet acetic acid, organophosphorus compounds or organonitrogen compounds and optionally carbonyl-yielding compounds of common me tals is taken from the carbonylation reactor and intro-duced through llne 1 into a separating s-tage 2. The pro-duct stream compr~sed o~ gaseous and liquid matter has a temperature o~ 0 180C, pre~erably 15 - 75C, Separat-ing stage 2 1s compri~ed of a separator and a column down-stream thereo~O It is ma~ntained under a pressure o~ 1 -3.5 bars. The products ~lowl~g through line 1 are separated in separating stage 2 into a llquid matter portion which is removed through line ~, and into a gaseous matter portion which has ~olatile iodine compound~ recoverable by the pre-sent process contained therein, consistentiwith their par-tial pr ssure. The gas flowing to the head o~ the separat-ing stage 2 pre~erably has a temperature o~ 15 - 30C. It is removed through line 4 and introduced wholly or partially ~ 7 ~
into the base portion o~ scrubbing column 5 which is pro-vided with trays, or packed, to improve the contact between gas and liquid. A portlon of the gaseous products is re-moved ~or scrubbing whilst the bulk is recycled through line 6 into the carbonylation reactor. The scrubbing column 5 is ~upplied overhead through line 7 with methyl acetate ha~ing a temperature o~ ~20 to -40C and the of~-gas flow-ing upwardly therein is scrubbed countercurrently there-with The ratio of gas ~olume to liquid volume is (5 - 100):
1, pre~erably (10 - 50) : 1, Scrubbing l~quid loaded with iodine compounds is recycled through line 8 into the carbo-nylation reactor. Iodine-free off-gas issues ~rom the scrubbing colum~ through line 9. In the e~ent of the entire gas stre~m being used ln the scrubbing stage, the bulk of the scrubbed o~f-gas is introduced through line 10 into the carbonylation reactor whilst a portion thereo~, which corres-ponds to the port~on use~ for scrub~ing as described abo~e, is removed from the system through line g.
The liter data in the ~ollowing Examples are based on standard condit~ons (0C and 1.013 bar).
Example 1 (Scrubbing ~otal gas stream~
6250 g/h reaction product was taken from the carbony lation reactor and introduced through line 1 ~nto the base portion oi separating ætage 2. It was maintained at a tem-perature o~ 60C and the product was separated into gaseous matter and liquid matter. 6150 g/h liquid matter was re-moved through line 3. 59 l/h o~f-gas composed approximately o~ (in volume %) 76.1 /0 C0s ~.1 % C02, 2 % methane9 1~5 %
hydrogen, 10.5 % nitrogen, 5.2 % methyl iodide and 1.6 %
~ 7~
methyl acetate was obtained at the head of separating stage
2 at a temperature of 20C under a pressure of 1.2 bars. rne o~-gas was introduced through line 4 into the base portion of scrubbing column 5 comprising 20 trays. 1110 g/h methyl acetate, corresponding to the methyl acetate conversion in the carbonylation zone, with a temperature of -20C was in-troduced near the head of column 5 through line 7 and o~-gas flowing upwardly therein was scrubbed countercurrently therewith, 0~-gas and methyl acetate were used in a ratio by volume o~ 49.5 : 1. 1132 g/h scrubbing liquid which con-tained about 1.7 wgt % methyl iodide, i.e. the entire me-thyl iodide inltially present in the off-gas, was removed through line 8. 55 l/h gas free from methyl iodide and sub-stantially free ~rom methyl acetate issued at the head o~
the scrubbing column through line 9. 35 l/h o~ such gas was recycled through line 10 into the carbonylation reactor and 20 l/h was removed through line 9.
Example 2 (Scrubbing total gas stream3 23 450 g/h reaction product was taken from the carbony-lation reactor and introduced through line 1 into the base portion of separating stage 2, in which it was separated at 70C into gaseous matter and liquid matter. 23 312 g/h li-quid matter was removed through line 3. 76 l/h o~-gas com-posed approximately o~ (~olume %~ 5.6 ~ methyl iodide, 1.6 %
methyl acetate, 73.5 % C0, 1~6 % C0~, 2~6 % methane, 1.4 %
hydrogen and 13.6 % nitrogen was obtained at the head o~
separating stage 2 a~ a temperature o~ 25C under a pressure o~ 2.4 bars, The gas was i~troduced through line 4 into scrubbing column 5~ 2592 g/h methyl acetate, corresponding to the methyl acetate conversion in the carbonylation zone, ~ 7'~
with a temperature of -5C was introduced through line 7 into the head portion o~ column 5 and the off gas-flowing upwardly in the column was scrubbed countercurrently there-with. O~ gas and methyl acetate were used in a ratio by volume of 27.~ : 1. 2623 g/h scrubbing liquid which con-tained about 1 wgt % methyl iodide~ i,e. all the methyl iodide initlally present in the off-gas, was removed through line 8. 71 l/h methyl iodide-~r2e gas, o~ which 39 l/h was recycled into the carbonylation reactor through line 10 and 32 l/h was removed through line 9 9 was obtained near the head o~ the scrubbing column through line 9 Example 3 (Scrubbing part~al stream) 4140 g/h reation product was taken from the carbonyla-tion reactor and introduced into separating stage 2, in which it was separated into gaseous matter and liquid mat-ter at 50C. 3986 g/h liquid matter was remoYed through line 3. 128 l/h off-gas composed approximately o~ (volume %) 50.8 % CO, 26.5 % hydrogen, 10.2 ~ methane J 0.8 % C02, 4.7 %
nitrogen 5.5 % methyl iodide and 1.5 % methyl acetate was obtained at the head of separating stage 2 at 22C under a pressure o~ 1.5 bars. 77 l/h o~f~gas was directly recycled into the reactor through line 6. A 51 l/h portion wa~ in-troduced into scrubbing column 5 through l~e 4. 720 g/l methyl acetate which had a temperature o~ -25C was intro-duced into th~ head portion of column 5 and the gas flow-ing upwardly therein was scrubbed countercurrently therewith.
Of*-gas and methyl acetate were used in a ratio by ~lume o~
66 : 1. 740 g/h scrubbing liquid which contained 2.3$ wgt %
methyl iodide, i.e. all the methyl iodide initially present ~ 7~
in the off-gas stream admitted to the scrubbing stage, was removed through line 8. 47.5 l/h methyl iodide-~ree off-gas which was removed from the system through line 9, was ob-tained at the head of the scru`bbing column.
the scrubbing column through line 9. 35 l/h o~ such gas was recycled through line 10 into the carbonylation reactor and 20 l/h was removed through line 9.
Example 2 (Scrubbing total gas stream3 23 450 g/h reaction product was taken from the carbony-lation reactor and introduced through line 1 into the base portion of separating stage 2, in which it was separated at 70C into gaseous matter and liquid matter. 23 312 g/h li-quid matter was removed through line 3. 76 l/h o~-gas com-posed approximately o~ (~olume %~ 5.6 ~ methyl iodide, 1.6 %
methyl acetate, 73.5 % C0, 1~6 % C0~, 2~6 % methane, 1.4 %
hydrogen and 13.6 % nitrogen was obtained at the head o~
separating stage 2 a~ a temperature o~ 25C under a pressure o~ 2.4 bars, The gas was i~troduced through line 4 into scrubbing column 5~ 2592 g/h methyl acetate, corresponding to the methyl acetate conversion in the carbonylation zone, ~ 7'~
with a temperature of -5C was introduced through line 7 into the head portion o~ column 5 and the off gas-flowing upwardly in the column was scrubbed countercurrently there-with. O~ gas and methyl acetate were used in a ratio by volume of 27.~ : 1. 2623 g/h scrubbing liquid which con-tained about 1 wgt % methyl iodide~ i,e. all the methyl iodide initlally present in the off-gas, was removed through line 8. 71 l/h methyl iodide-~r2e gas, o~ which 39 l/h was recycled into the carbonylation reactor through line 10 and 32 l/h was removed through line 9 9 was obtained near the head o~ the scrubbing column through line 9 Example 3 (Scrubbing part~al stream) 4140 g/h reation product was taken from the carbonyla-tion reactor and introduced into separating stage 2, in which it was separated into gaseous matter and liquid mat-ter at 50C. 3986 g/h liquid matter was remoYed through line 3. 128 l/h off-gas composed approximately o~ (volume %) 50.8 % CO, 26.5 % hydrogen, 10.2 ~ methane J 0.8 % C02, 4.7 %
nitrogen 5.5 % methyl iodide and 1.5 % methyl acetate was obtained at the head of separating stage 2 at 22C under a pressure o~ 1.5 bars. 77 l/h o~f~gas was directly recycled into the reactor through line 6. A 51 l/h portion wa~ in-troduced into scrubbing column 5 through l~e 4. 720 g/l methyl acetate which had a temperature o~ -25C was intro-duced into th~ head portion of column 5 and the gas flow-ing upwardly therein was scrubbed countercurrently therewith.
Of*-gas and methyl acetate were used in a ratio by ~lume o~
66 : 1. 740 g/h scrubbing liquid which contained 2.3$ wgt %
methyl iodide, i.e. all the methyl iodide initially present ~ 7~
in the off-gas stream admitted to the scrubbing stage, was removed through line 8. 47.5 l/h methyl iodide-~ree off-gas which was removed from the system through line 9, was ob-tained at the head of the scru`bbing column.
Claims (8)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for recovering iodine compounds from the off-gas originating from the reaction of methyl acetate or dimethyl ether or mixtures of methyl acetate and dimethyl ether with carbon monoxide to give acetic anhydride or with carbon monoxide and hydrogen to give acetic anhydride and ethylidene diacetate in the presence of a catalyst system consisting of carbonyl complexes of noble metals of group VIII of the Periodic System of the elements, an iodine compound, acetic acid, and an organophosphorus or organonitrogen compound which comprises: subjecting off-gas which is removed together with liquid reaction products, wholly or partially to countercurrent scrubbing treatment with methyl acetate at temperatures of -40°C up to +20°C.
2. A process as claimed in claim 1, wherein the catalyst system further comprises carbonyl-yielding compounds of common metal.
3. A process as claimed in claim 1, or 2, wherein the off-gas is scrubbed using methyl acetate in a quantity corresponding to the quantity of methyl acetate converted in the reaction zone.
4. A process as claimed in claim 1, or 2, wherein the off-gas and methyl acetate are used in the countercurrent scrubbing stage in a ratio by volume of (5-100):1.
5. A process as claimed in claim 1, or 2, wherein the off-gas and methyl acetate are used in the countercurrent scrubbing stage in a ratio by volume of (10-50):1.
6. A process as claimed in claim 1, or 2, wherein the methyl acetate used for scrubbing and loaded with iodine compounds is recycled into the reaction zone.
7. A process as claimed in claim 1, or 2, wherein the off-gas contains carbon monoxide, carbon dioxide, hydrogen, nitrogen, methane, methyl acetate and iodine compounds.
8. A process as claimed in claim 1, or 2, wherein a portion of the off-gas consisting predominantly of carbon monoxide and freed from iodine compounds by countercurrent scrubbing treatment is removed, the balance portion being recycled into the reaction zone.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3137782.3 | 1981-09-23 | ||
| DE19813137782 DE3137782A1 (en) | 1981-09-23 | 1981-09-23 | METHOD FOR RECOVERY OF IODINE COMPOUNDS FROM THE EXHAUST GAS FROM CARBONYLATION REACTIONS |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1214472A true CA1214472A (en) | 1986-11-25 |
Family
ID=6142374
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000410911A Expired CA1214472A (en) | 1981-09-23 | 1982-09-07 | Process for recovering iodine compounds from the off- gas of carbonylation reactions |
Country Status (9)
| Country | Link |
|---|---|
| EP (1) | EP0075730B1 (en) |
| JP (1) | JPS6042217B2 (en) |
| AT (1) | ATE7895T1 (en) |
| AU (1) | AU551148B2 (en) |
| BR (1) | BR8205558A (en) |
| CA (1) | CA1214472A (en) |
| DE (2) | DE3137782A1 (en) |
| MX (1) | MX162643A (en) |
| ZA (1) | ZA826942B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5380929A (en) * | 1988-07-13 | 1995-01-10 | Hoechst Aktiengesellschaft | Process for the preparation of acetic acid and acetic anhydride |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3331548A1 (en) * | 1983-09-01 | 1985-03-21 | Hoechst Ag, 6230 Frankfurt | METHOD FOR SEPARATING IODINE AND ITS COMPOUNDS FROM CARBONYLATION PRODUCTS OBTAINED FROM CARBONYLATING DIMETHYL ETHER, METHYL ACETATE OR METHANOL |
| DE3440647A1 (en) * | 1984-11-07 | 1986-05-07 | Hoechst Ag, 6230 Frankfurt | Acid anhydride prodn. from ester(s) or ether(s) |
| DE3440646A1 (en) * | 1984-11-07 | 1986-05-07 | Hoechst Ag, 6230 Frankfurt | CARRIER CATALYST FOR THE PRODUCTION OF MONOCARBONIC ACID ANHYDRIDES |
| JP3377555B2 (en) * | 1993-05-31 | 2003-02-17 | ダイセル化学工業株式会社 | Method for removing iodine compound contained in carbonylation reaction product |
| WO2012064689A1 (en) * | 2010-11-12 | 2012-05-18 | Eastman Chemical Company | Processing gaseous streams resulting from carbonylation process |
| JP6546709B1 (en) * | 2018-07-02 | 2019-07-17 | 株式会社ダイセル | Method for producing acetic acid |
| CN113603563B (en) * | 2021-07-28 | 2023-05-26 | 山东新和成维生素有限公司 | Method for recycling aromatization catalyst |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1986322A (en) * | 1928-09-13 | 1935-01-01 | Du Pont | Method of purifying a mixture of acetaldehyde and acetic anhydride |
| US4246195A (en) * | 1978-10-06 | 1981-01-20 | Halcon Research And Development Corporation | Purification of carbonylation products |
| DE2901359A1 (en) * | 1979-01-15 | 1980-07-24 | Basf Ag | METHOD FOR REMOVING IODINE FROM ORGANIC COMPOUNDS |
-
1981
- 1981-09-23 DE DE19813137782 patent/DE3137782A1/en not_active Withdrawn
-
1982
- 1982-08-25 AT AT82107786T patent/ATE7895T1/en active
- 1982-08-25 DE DE8282107786T patent/DE3260251D1/en not_active Expired
- 1982-08-25 EP EP82107786A patent/EP0075730B1/en not_active Expired
- 1982-09-07 CA CA000410911A patent/CA1214472A/en not_active Expired
- 1982-09-22 JP JP57164195A patent/JPS6042217B2/en not_active Expired
- 1982-09-22 BR BR8205558A patent/BR8205558A/en unknown
- 1982-09-22 ZA ZA826942A patent/ZA826942B/en unknown
- 1982-09-22 AU AU88598/82A patent/AU551148B2/en not_active Ceased
- 1982-09-22 MX MX194480A patent/MX162643A/en unknown
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5380929A (en) * | 1988-07-13 | 1995-01-10 | Hoechst Aktiengesellschaft | Process for the preparation of acetic acid and acetic anhydride |
| EP0350635B2 (en) † | 1988-07-13 | 2002-07-17 | Celanese Chemicals Europe GmbH | Process for the preparation of acetic acid and acetic anhydride |
Also Published As
| Publication number | Publication date |
|---|---|
| AU551148B2 (en) | 1986-04-17 |
| JPS5865229A (en) | 1983-04-18 |
| ZA826942B (en) | 1983-08-31 |
| JPS6042217B2 (en) | 1985-09-20 |
| DE3260251D1 (en) | 1984-07-19 |
| ATE7895T1 (en) | 1984-06-15 |
| BR8205558A (en) | 1983-08-30 |
| EP0075730A1 (en) | 1983-04-06 |
| EP0075730B1 (en) | 1984-06-13 |
| DE3137782A1 (en) | 1983-03-31 |
| AU8859882A (en) | 1983-03-31 |
| MX162643A (en) | 1991-06-10 |
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