Production of acetic acid

FIELD: chemistry.

SUBSTANCE: method comprises steps of (a) carbonylation of methanol in a carbonylation reactor at temperature from 150 to 250°C in the presence of a catalyst, a catalyst stabiliser, water and methyl iodide to form a reaction mixture containing a catalyst, catalyst stabiliser, acetic acid, methanol, methyl iodide, methyl acetate and water; and (b) feeding the obtained reaction mixture from the carbonylation reactor directly into a distillation column for distillation of the reaction mixture with separation of the bottom stream containing the catalyst and catalyst stabiliser, a side stream containing acetic acid and water, and an overhead stream containing methanol, methyl acetate, methyl iodide and water.

EFFECT: method according to the invention excludes use of an instantaneous vaporiser.

15 cl, 1 dwg, 1 ex

 

The technical FIELD TO WHICH the INVENTION RELATES

The invention relates to the production of acetic acid by carbonyliron methanol. More specifically, the invention relates to a method for producing acetic acid, which eliminates the use of the evaporator instant action (flash evaporator).

The LEVEL of TECHNOLOGY

Known to produce acetic acid carbonyliron methanol (see U.S. patent No. 5817869). In the modern method of obtaining acetic acid, the reaction mixture withdrawn from the reactor and separated using an evaporator instant action on the liquid fraction comprising the catalyst and the catalyst stabilizer, and steam fraction, which includes obtained acetic acid, reagents, water, methyliodide and impurities formed during the carbonylation reaction. Then the liquid fraction is recycled to the reactor for carbonylation. Then steam fraction is sent to the so-called "distillation head ring". In the distillation head of a shoulder strap acetic acid is separated from other components.

Distillation of the head of a shoulder strap separates the upper shoulder strap, including methyliodide, water, methanol and methyl acetate stream of acetic acid, including acetic acid, a small amount of water and heavy contaminants. The flow of acetic acid is passed into the drying Colo is well to remove the water and then subjected to the so-called "distillation tail fractions" to remove heavy impurities, such as propionic acid.

One problem with the modern way, is that the catalyst is usually expensive metal rhodium or iridium, cannot be removed due to entrainment of it in the vapor phase or settling on the walls of the evaporator instant action.

Another problem associated with modern fashion, is that the catalysts often are deactivated during the gas-liquid separation instant evaporation. Rhodium and iridium catalysts require high water concentration to stabilize. During the gas-liquid separation instantaneous evaporation of a significant amount of water enters the vapour phase, and thereby rhodium and iridium catalysts become unstable due to the lack of water at a sufficient level.

In addition, equipment for production of acetic acid must have a high corrosion resistance. The evaporator instantaneous often design of corrosion-resistant metals, such as alloys Hastelloy B-2 and Zirconium 702. These metals are very expensive.

You want a new method to produce acetic acid. Ideally, the method would exclude the application of the evaporator instant action.

The INVENTION

The invention is a method of obtaining acetic acid. The way in which incorporates both stages, in which conduct the carbonylation of methanol with formation of a reaction mixture comprising a catalyst, a stabilizer, catalyst, acetic acid, methanol, methyliodide, methyl acetate, water and carbon monoxide, and introducing at least part of the reaction mixture to a distillation column for separation into a bottom stream comprising the catalyst and the catalyst stabilizer, the side product stream comprising acetic acid and water, and the flow of the upper shoulder strap, including methanol, methyl acetate, methyliodide and water. The method according to the invention eliminates the use of the evaporator instant action.

DETAILED description of the INVENTION

The method according to the invention comprises the carbonylation of methanol. The carbonylation reaction is carried out in the presence of a carbonylation catalyst and the catalyst stabilizer. Suitable catalysts for the carbonylation include those that are known in the industrial production of acetic acid. Examples of suitable carbonylation catalysts include rhodium catalysts and iridium catalysts.

Suitable rhodium catalysts indicated, for example, in U.S. patent No. 5817869. Suitable rhodium catalysts include metal rhodium and compounds of rhodium. Compounds of rhodium is preferably selected from the group consisting of rhodium salts, rhodium oxides, acetate is in rhodium, radiogenicity compounds, coordination compounds of rhodium and the like and mixtures thereof. More preferred compounds of rhodium are selected from the group consisting of Rh2(CO)4I2Rh2(CO)4Br2Rh2(CO)4Cl2Rh(CH3CO2)2Rh(CH3CO2)3, [H]Rh(CO)2I2, the like and mixtures thereof. The most preferred compounds of rhodium are selected from the group consisting of [H]Rh(CO)2I2Rh(CH3CO2)2and the like, and mixtures thereof.

Suitable iridium catalysts indicated, for example, in U.S. patent No. 5932764. Suitable iridium catalysts include metallic iridium and iridium compounds. Examples of suitable iridium compounds include IrCl3, IrI3, IrBr3, [Ir(CO)2I]2, [Ir(CO)2Cl]2, [Ir(CO)2Br]2, [Ir(CO)4I2]-Η+, [Ir(CO)2Br2]-H+, [Ir(CO)2I2]-Η+, [Ir(CH3)I3(CO)2]-H+Ir4(CO)12, IrCl3.4H2O, IrBr3.4H2O Ir3(CO)12Ir2O3, IrO2, Ir(acac)(CO)2, Ir(acac)3Ir(OAc)3, [Ir3O(OAc)6(H2O)3][OAc] and H2[IrCl6]. The iridium compounds are preferably selected from the group consisting of acetates, oxalates, azeta is Matov and the like, as well as their mixtures. More preferred compounds of iridium are acetates.

The iridium catalyst is preferably used with socialization. Preferred socializaton include metals and metal compounds selected from the group consisting of osmium, rhenium, ruthenium, cadmium, mercury, zinc, gallium, indium and tungsten, their compounds and the like and mixtures thereof. More preferred socializaton selected from the group consisting of compounds of ruthenium and osmium compounds. The most preferred socialization are compounds of ruthenium. Preferably socializaton are acetates.

The carbonylation reaction is carried out in the presence of a catalyst stabilizer. Suitable stabilizers catalysts include those known in the industry. There are basically two types of stabilizers catalyst. The first type of catalyst stabilizer is a salt, such as metal iodide such as lithium iodide. The second type of catalyst stabilizer is mesolevel stabilizer. Preferred nesolenym stabilizers are oxides of pentavalent elements of Group VA (see U.S. patent No. 5817869). The preferred phosphine oxides. Most preferred are the oxides of triphenylphosphine.

The carbonylation reaction prefers the equipment is carried out in the presence of water. The concentration of water present is preferably from about 2 weight percent to about 14 weight percent calculated on the total weight of the reaction medium. More preferably the concentration of water varies from about 2 weight percent to about 10 weight percent. Most preferably the concentration of water is from about 4 weight percent to about 8 weight percent.

The carbonylation reaction is preferably carried out in the presence of acetate. The acetate can be formedin situ. If desirable, the acetate can be added to the reaction mixture as the starting material. The concentration of acetate is preferably from about 2 weight percent to about 20 percent by weight calculated on the total weight of the reaction medium. More preferably, the concentration of acetate ranges from about 2 weight percent to about 16 weight percent. Most preferably, the concentration of acetate is from about 2 weight percent to about 8 weight percent. An alternative to the carbonylation reaction can be used methyl acetate or a mixture of methyl acetate and methanol flows from by-products of hydrolysis or methanolysis of polyvinyl acetate.

The carbonylation reaction is carried out in the presence under the conditions. Methyliodide represents the activator is utilizator. Concentration under the conditions preferably ranges from about 0.6 weight percent to about 36 weight percent calculated on the total weight of the reaction medium. More preferably the concentration under the conditions varies from about 4 weight percent to about 24 weight percent. Most preferably the concentration under the conditions ranges from about 6 weight percent to about 20 weight percent. Alternative methyliodide can be formed in the carbonylation reactor for adding moduledata (HI).

In the carbonylation reactor for serving methanol and carbon monoxide. The methanol supplied to the carbonylation reaction may come from a plant for producing methanol from synthesis gas or from any other source. Methanol does not react directly with carbon monoxide with the formation of acetic acid. It is converted in methyliodide reaction with iodovidonum present in the reactor for the production of acetic acid, and then reacts with carbon monoxide and water with the formation of acetic acid and regeneration of moduledata. Carbon monoxide not only becomes part of the molecule of acetic acid, but also plays an important role in the formation and stabilization of the active catalyst.

The carbonylation reaction is preferably carried out at a temperature within the range from the Colo 150°C to about 250°C. More preferably the reaction is carried out at a temperature within the range from about 150°to about 200°C. the carbonylation Reaction is preferably performed at a pressure within the range from about 200 psig (1378,8 kPa gauge) to about 1000 psig (6,894 MPa gauge). More preferably the reaction is carried out at a pressure within the range from about 300 psig (2068,2 kPa gauge) to about 500 psig (3,447 MPa gauge).

The reaction mixture away from the reactor and instead be sent to the evaporator instant action, send directly to a distillation column to separate at least three threads: a bottom liquid stream, a liquid side stream and the main steam flow.

The distillation column preferably has at least 10 real plates. More preferably, the distillation column has at least 14 real plates. Most preferably, the distillation column has at least 18 real plates. Real one plate is equal to approximately 0.6 of theoretical plates. Real plates can be a disc partition or nozzles. The reaction mixture was fed to a distillation column bottom or at the level of the first plates of the column.

The distillation column is preferably operates at a pressure of th the ESD shoulder straps within the range from 20 psia (1.4 kg/cm 2, 137,88 kPa) to 40 psia (2.8 kg/cm2, 275,76 kPa) (absolute). More preferably the pressure head ring varies within the range from 25 to 35 psia (172,35-241,29 kPa, absolute). The temperature of the head of a shoulder strap preferably varies within the range of from 95°C. to 135°C. More preferably the temperature of the head ring is within the range from 100ºC to 125º. Most preferably, the temperature of the head ring varies within the range from 110°C to 120°C. This steam head wrap includes water, carbon monoxide, carbon dioxide, methyliodide, methyl acetate, methanol and acetic acid.

The distillation column is preferably operates at a pressure in the bottom part within the range from 25 psia (172,35 kPa, absolute) to about 45 psia (310,23 kPa, absolute). More preferably the pressure in the bottom part varies within the range from 30 psia (206,82 kPa, absolute) up to 40 psia (275,76 kPa, absolute). The temperature in the bottom part preferably varies within the range from 115°to 155°C. More preferably the temperature at the bottom is within the range of from 125°C. to 135°C. CBM stream comprises a catalyst, a stabilizer, catalyst, acetic acid and water.

Liquid side zipper preferably operates at a pressure within the range from 25 psia (172,35 kPa, absolute) to about 45 psia (310,kA, the absolute). More preferably the pressure side product varies within the range of 30 psia (206,82 kPa, absolute) up to 40 psia (275,76 kPa, absolute). The temperature of the side product preferably varies within the range from 110°C to 140°C. More preferably the temperature of the side product varies within the range from 120°C to 130°C. and a Side zipper preferably selected between the plates from the fifth to the eighth. The side zipper is a raw acetic acid, which comprises acetic acid, water and impurities such as propionic acid.

The flow downstream of a shoulder strap of the distillation column is preferably condensed and separated in a settling tank for easy water phase and a heavy organic phase. Heavy organic phase includes methyliodide and acetate. Easy aqueous phase comprises mainly water (more than 50%), acetic acid and methyl acetate. The aqueous phase is sent to the top of the distillation column as phlegmy or part of its optional return recirculation in the carbonylation reaction.

Stream side product is not necessarily subjected to additional treatment, such as drying distillation to remove water and distillation tail fractions to remove heavy impurities such as propionic acid.

The following example only illustrates sabreena. Qualified professionals in this area of technology will have in mind the many variations that are within the invention and scope of the claims of the patent.

EXAMPLE

This method according to the invention simulated using the software Aspen Plus, and obtained the following results. As shown in figure 1, the mixture for carbonylation (100 parts by weight), including 6,37% of water, 0.13% of the carbon monoxide, and 0.09% of carbon dioxide, 2,70% moduledata, 12,91% under the conditions, 2,85% acetate, 0.02% methanol, 65,57% acetic acid, 0.04% of propionic acid, 9.28 are% stabilizer catalyst and 0.04% of the catalyst, is fed into the distillation column at the level of the first plate. The distillation column has 11 theoretical plates, or 18 real plates.

Head wrap distillation column has a pressure to 32.7 psia (225,43 kPa, absolute) and a temperature of 116°C. Steam head wrap (20.6 parts by weight) includes water, carbon monoxide, carbon dioxide, methyliodide, methyl acetate, methanol and acetic acid. The flow downstream of a shoulder strap cooled to a temperature of 38°C, and the condensate drains into a sump for liquid separation.

Obtained in the sump of the heavy phase (12.8 parts by weight), which includes 0,46% water, 0.02% carbon monoxide, or 0.27% of carbon dioxide, 88,83% under the conditions, 8.34% acetate and 2,08% vinegar is Oh acid, return recirculation to the reactor. Part of the light phase (to 1.8 parts by weight), which includes EUR 54.15% water, and 0.09% of carbon dioxide, 3,43% under the conditions, 8,03% acetate, 0,36% methanol and 33,94% acetic acid, and also return recirculation to the reactor. The rest of the light phase (6,3 parts by weight) are referred to as phlegmy for irrigation the top of the distillation column.

The bottom part of the distillation column operates at a pressure of 35.4 psia (244,05 kPa, absolute) and a temperature of 132°C. the Flow of the cubic residue (of 67.5 parts by weight) includes 5,58% water, 0.04% of carbon monoxide, 0.30% of carbon dioxide, 3.99% of moduledata, 1,23% under the conditions, 1,84% acetate, 0.01% methanol, 73,18% acetic acid, 0.05% of propionic acid, 13,72% of the stabilizer, catalyst and 0.06% of the catalyst. This direct flow recirculation in the reactor.

Liquid side wrap (19.1 parts by weight) at a pressure 34,9 psia (240,6 kPa, absolute) and a temperature of 127°C are selected with the sixth plates, counting from the bottom of distillation columns. This thread includes 8,82% water, to 0.04% of moduledata, 3,80% under the conditions, 2,22% acetate, 0.02% methanol, 85,06% acetic acid and 0.04% propionic acid. The vast majority (94%) of the stream is a raw acetic acid, which flows in the equipment downstream dewatering and extraction of pure acetic acid. The remaining 6% of the return flow as phlegmy in the distillation section of the column below the selection liquid side product.

1. The method of obtaining acetic acid, including the stage at which:
(a) conduct the carbonylation of methanol in a carbonylation reactor at a temperature of from 150 to 2500In the presence of a catalyst, stabilizer, catalyst, water and under the conditions, with formation of a reaction mixture comprising a catalyst, a stabilizer, catalyst, acetic acid, methanol, methyliodide, methyl acetate and water; and
(b) the resulting reaction mixture directly from the carbonylation reactor is sent to a distillation column for distillation of the reaction mixture with the Department of the cubic stream comprising the catalyst and the catalyst stabilizer, side product stream comprising acetic acid and water, and the flow downstream of a shoulder strap, including methanol, methyl acetate, methyliodide and water.

2. The method according to claim 1, in which the bottom stream from step (b) return recirculation in the carbonyl process stage (a).

3. The method according to claim 1, in which the flow downstream product from stage (b) return recirculation in the carbonyl process stage (a).

4. The method according to claim 1, in which the flow downstream of a shoulder strap is subjected to separation of the phases on the light aqueous phase comprising water, acetic acid and methyl acetate, and heavy organic phase comprising methyliodide and acetate.

5. The method according to claim 4, in which the heavy organic phase in the rotating recirculation in the carbonyl process stage (a).

6. The method according to claim 4, in which the light aqueous phase is recycled to the distillation stage (b) or the carbonyl process in stage (a).

7. The method according to claim 1, further comprising a distillation stream side product to remove the water.

8. The method according to claim 1, wherein the catalyst is selected from the group consisting of rhodium catalysts, iridium catalysts.

9. The method according to claim 1, wherein the catalyst is a rhodium catalyst.

10. The method according to claim 9, in which the catalyst stabilizer selected from the group consisting of oxides of pentavalent elements of Group VA, iodide salts of the metals and mixtures thereof.

11. The method according to claim 9, in which the stabilizer catalyst is a phosphine oxide.

12. The method according to claim 9, in which the catalyst stabilizer is triphenylphosphine.

13. The method according to claim 9, in which the catalyst stabilizer is an iodide salt of the metal.

14. The method according to claim 9, in which the catalyst stabilizer is lithium iodide.

15. The method according to claim 1, in which the concentration of water at the stage of (a) up to 10 weight percent of the reaction mixture.



 

Same patents:

FIELD: chemistry.

SUBSTANCE: invention relates to an improved method of producing acetic acid, involving (a) catalytic reaction of methanol or reactive derivative thereof with carbon monoxide in the presence of a group VIII metal based homogeneous catalyst and methyl iodide as a promoter in a reaction vessel which contains a liquid reaction mixture containing acetic acid, water, methyl acetate, methyl iodide and a homogeneous catalyst, wherein the reaction vessel operates at reactor pressure; (b) removing the reaction mixture from the reaction vessel and feeding the removed reaction mixture along with additional carbon monoxide into a pre-evaporation/post-reaction vessel operating at low pressure, which is below the pressure in the reaction vessel; (c) blowing light fractions in the pre-evaporation vessel and simultaneous consumption of methyl acetate in the pre-evaporation/post-reaction vessel to obtain a pre-evaporation mixture which is rich in acetic acid and is poor in methyl iodide and methyl acetate compared to the reaction mixture; (d) removing the pre-evaporation reaction mixture from the pre-evaporation/post-reaction vessel and feeding the pre-evaporation mixture into the evaporation vessel; (e) flash evaporation of the stream of raw acetic acid from the mixture in the evaporation vessel operating at pressure which is considerably lower than that of the pre-evaporation/post-reaction vessel; (f) recycling the residue after evaporation process from the evaporation vessel into the reaction vessel and (g) purifying the stream of the raw product. Low content of methyl iodide and methyl acetate in the formed stream of evaporated raw product eliminate the role of light fraction columns as the bottleneck of the scheme.

EFFECT: method increases efficiency of the process; eliminated the need for a high-pressure absorber, which reduces capital costs and operating costs.

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FIELD: chemistry.

SUBSTANCE: invention relates to a method of increasing efficiency and catalyst stability when producing methyl acetate, involving carbonylation of dimethyl ether based material with carbon monoxide in virtually anhydrous conditions in the presence of a zeolite catalyst which is efficient in said carbonylation, wherein the reaction is carried out at temperature ranging from 275°C to 350°C, and in the presence of hydrogen.

EFFECT: high efficiency and catalyst stability.

14 cl, 9 ex, 4 dwg, 1 tbl

FIELD: chemistry.

SUBSTANCE: invention relates to improved carbonylation methods in order to produce acetic acid, the methods involving: (a) carbonylating methanol or reactive derivatives thereof in the presence of water, a catalyst selected from a group which includes rhodium catalysts, iridium catalysts and mixtures thereof, and methyl iodide as a promoter to form an acetic acid containing reaction mixture in the reactor; (b) separating the stream of the acetic acid containing reaction mixture into a liquid recycled stream and a crude product stream containing acetic acid, methyl iodide, methyl acetate and water; (c) feeding the crude product stream to a stripping column having a distillation zone; (d) purifying the crude product stream in the distillation zone of the stripping column to remove methyl iodide and methyl acetate and obtain a purified product stream, the purified product stream characterised lower concentration of methyl iodide and methyl acetate than the crude product stream, and wherein the step of purifying the crude product stream involves: (i) condensing overhead vapour from the distillation zone of the stripping column, (ii) decanting the condensed vapour to obtain a heavy phase mainly containing methyl iodide and a light phase mainly containing acetic acid and water, and (iii) refluxing at least a portion of the condensed heavy phase to the distillation zone of the stripping column; and (iv) recycling the light phase into the reactor; and (e) drawing a purified product stream from the stripping column.

EFFECT: content of acetic acid in the overhead vapour of the stripping column and content of water in the product stream of the stripping column (side cut) is reduced, which increases efficiency of purification.

17 cl, 3 dwg, 1 tbl

FIELD: chemistry.

SUBSTANCE: invention relates to a method of increasing efficiency and selectivity when producing methyl acetate, involving carbonylation of material based on dimethyl ether with carbon monoxide in virtually anhydrous conditions in the presence of a zeolite catalyst which is efficient in said carbonylation, wherein the reaction is carried out at temperature ranging from higher than 250 to 350°C, and at pressure ranging from higher than 10 to 100 bar (isobar).

EFFECT: high efficiency and selectivity when producing methyl acetate.

15 cl, 11 dwg, 3 ex

FIELD: chemistry.

SUBSTANCE: invention relates to improved carbonylation methods for producing acetic acid, one of which involves: (a) carbonylation of methanol or reactive derivative thereof in the presence of water, a catalyst selected from rhodium catalysts, iridium catalysts and mixtures thereof, a promoter from methyl iodide to form a reaction mixture with acetic acid in a reactor; (b) separating the stream of the reaction mixture with acetic acid into a liquid recirculation stream and a first stream of the crude product which contains acetic acid; (c) feeding the first stream of crude product into a column for distillation of light fractions; (d) distillation of the stream of crude product to remove low-boiling components as the overhead product and form a first stream of the purified product in form of a side stream and a liquid residual stream, the liquid residual stream primarily consisting of acetic acid, where the first stream of purified product is fed into a dehydration column, after which the dried product is fed into a column for distillation of heavy fractions, and acetic acid is collected in form of an overhead product from the column for distillation of heavy fractions; (e) evaporating at least a portion of the liquid residual stream to obtain a second product stream; and (f) feeding the second product stream after condensation or compression thereof for further processing after merging with the first stream of purified product into said dehydration column. The invention also relates to an apparatus for producing acetic acid, comprising: (a) a reactor for carbonylation of methanol or reactive derivatives thereof in the presence of water, a catalyst selected from rhodium catalysts, iridium catalysts and mixtures thereof, and a promoter from methyl iodide to form a reaction mixture with acetic acid in the reactor; (b) a flash evaporation apparatus connected to the reactor and configured for inlet of the stream of the reaction mixture and separation thereof into (i) a liquid recirculating stream and (ii) a crude first product stream containing acetic acid; (c) a column for distillation of light fractions, which is connected to the flash evaporation apparatus which is configured for separation of low-boiling components in form of an overhead product from the first product stream and formation of a first stream of purified product in form of a side stream, and a liquid residual stream; (d) a dehydration column connected to the column for distillation of light fractions; (e) a column for distillation of heavy fractions connected to the dehydration column; and (f) an evaporation reservoir, also connected to the column for distillation of light fractions, for evaporation of at least a portion of the liquid residual stream and configured to feed a second product stream into the dehydration column; or a column for distillation of the liquid residual stream to form a stream of the purified product and meant for feeding it into the dehydration column or into the column for distillation of heavy fractions, where the column for distillation of the liquid residual stream is a stripping column. The apparatus and methods of producing acetic acid thus involve extraction of the product from the residue of light fractions in a stripping column and feeding the extracted acid for further processing in order to increase efficiency of the system.

EFFECT: reduced load on the column for distillation of light fractions; the load on the dehydration column can also be reduced in the embodiment, wherein further removal of water from the extracted acid is not necessary.

15 cl, 4 dwg, 2 tbl

FIELD: chemistry.

SUBSTANCE: invention relates to methods of removing acetaldehyde from a mixture of methyl acetate, methanol and acetaldehyde, one of which involves: (a) feeding the mixture of methyl acetate, methanol and acetaldehyde into a rectification column; (b) rectification of the mixture of methyl acetate, methanol and acetaldehyde at pressure of 68.95 kPa (10 pounds/square inch) or higher to form a vapour stream output from the top of the column which is rich in acetaldehyde compared to the mixture, and a bottom residue poor in acetaldehyde compared to the mixture; (c) returning as reflux a portion of the vapour stream which is output from the top of the column into the rectification column; and (d) removing a stream of the bottom residue poor in acetaldehyde from the rectification column, where temperature of the vapour stream from the top of the column ranges from 85°C to 115°C. The invention also relates to a method of producing acetic acid, involving: (a) cleaning the mixture of methyl acetate, methanol and acetaldehyde with removal of acetaldehyde by: (i) feeding the mixture of methyl acetate, methanol and acetaldehyde into a rectification column; (ii) rectification of the mixture of methyl acetate, methanol and acetaldehyde at pressure of 68.95 kPa (10 pounds/square inch) or higher to form a vapour stream which is output from the top of the column which is rich in acetaldehyde compared to the mixture, and a bottom residue poor in acetaldehyde compared to the mixture; (iii) returning as reflux a portion of the vapour stream output from the top of the column into the rectification column; and (iv) removing a stream of the bottom residue poor in acetaldehyde from the rectification column; (b) feeding the cleaned stream of bottom residue into the reaction mixture for carbonylation together with carbon oxide, where the reaction mixture for carbonylation contains water, a catalyst selected from rhodium catalysts, iridium catalysts or mixtures thereof, a promoter from methyl iodide and acetic acid; and (c) extracting acetic acid from the carbonylation mixture, where temperature of the stream which is output from the top of the column ranges from 85°C to 115°C.

EFFECT: improved methods.

15 cl, 8 dwg, 6 tbl, 16 ex

FIELD: chemistry.

SUBSTANCE: invention relates to an improved method of increasing catalytic activity when producing methyl acetate, involving carbonylation of dimethyl ether-based material with carbon monoxide in the presence of hydrogen in virtually anhydrous conditions at temperature ranging from more than 250°C to 350°C, in the presence of a zeolite catalyst which is efficient in said carbonylation, wherein concentration of dimethyl ether is at least 1 mol % with respect to the total amount of material.

EFFECT: improved method of increasing catalytic activity when producing methyl acetate.

13 cl, 4 ex, 3 tbl, 4 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to an improved method of increasing rate of reaction without a ruthenium promoter and reducing toxicity of the catalyst system when producing acetic acid via carbonylation of methanol and/or reactive derivative thereof with carbon monoxide in at least one carbonylation reaction zone, containing a liquid reaction composition which contains an iridium carbonylation catalyst, a methyl iodide cocatalyst, water in an a limited concentration, acetic acid, methyl acetate and indium and rhenium as promoters.

EFFECT: high efficiency of the method.

16 cl, 2 tbl, 2 ex

FIELD: chemistry.

SUBSTANCE: invention relates to an improved method of preventing precipitation of a catalyst system when producing acetic acid via carbonylation of methanol and/or reactive derivative thereof with carbon monoxide in at least one carbonylation reaction zone, containing a liquid reaction composition containing an iridium carbonylation catalyst, a methyl iodide cocatalyst, water in an a limited concentration, acetic acid, methyl acetate and boron and gallium as promoters.

EFFECT: combination of boron and gallium as promoters enables to avoid problems with precipitation which are observed in ruthenium-promoted reactions, and the rate of reaction also remains the same compared with conventional ruthenium promoters.

15 cl, 2 tbl, 1 ex

FIELD: chemistry.

SUBSTANCE: invention relates to an improved method of producing acetic acid through carbonylation of methanol and/or reactive derivative selected from methyl acetate, methyl iodide, dimethyl ether and mixtures thereof, carbon monoxide in the presence of a catalyst in a liquid reaction mixture containing methyl iodide and water in concentration of 0.1-30 wt %, wherein the catalyst includes a complex of a metal with a chelate-like ligand of general formula (I), wherein Z represents carbon, each of L1 and L2 represents a coordination group containing a donor P atom or a donor N atom; each R3 is independently selected from hydrogen, or a C1-C6 alkyl group, and M is selected from Rh and Ir; or general formula (II), wherein Z represents carbon, each of L3 and L4 represents a coordination group containing a donor P atom or a donor N atom, and M is selected from Rh and Ir.

EFFECT: method provides high selectivity of formation of acetic acid.

14 cl, 2 tbl, 6 ex

FIELD: chemistry.

SUBSTANCE: invention relates to an improved method of producing pure methacrylic acid, which involves: a) gas-phase oxidation of a C4 compound to obtain a methacrylic acid-containing gas phase, b) condensing the methacrylic acid-containing gas phase to obtain an aqueous methacrylic acid solution, c) separating at least a portion of the methacrylic acid from the aqueous methacrylic acid solution to obtain at least one methacrylic acid-containing raw product, d) separating at least a portion of methacrylic acid from the at least one methacrylic acid-containing raw product by thermal separation to obtain pure methacrylic acid, wherein at step (d), methacrylic acid is separated from at least a portion of at least one methacrylic acid-containing raw product by fractionation, and wherein the pure methacrylic acid is collected through a side outlet used for the fractionation column, and the amount of pure methacrylic acid collected over a certain time interval ranges from 40% to 80% of the amount of the methacrylic acid-containing raw product fed into the fractionation column over the same time interval. The invention also relates to an apparatus for producing methacrylic acid using said method, the apparatus comprising: a1) a gas-phase oxidation unit, b1) an absorption unit, c1) a separation unit, and d1) a purification unit, wherein the purification unit has at least one distillation column, wherein the at least one distillation column has at least one side outlet for pure methacrylic acid. The invention also relates to a method of producing methacrylic esters, polymethacrylate, polymethacrylic esters, which includes a step for said production of pure methacrylic acid.

EFFECT: obtaining an end product with fewer by-products while simplifying the process.

32 cl, 3 tbl, 4 dwg, 6 ex

FIELD: chemistry.

SUBSTANCE: invention relates to an improved method of producing acetic acid comprising the following steps: reacting methanol with carbon monoxide in a reaction vessel containing water, methyl iodide and methyl acetate in the presence of a group VIII metal based carbonylation catalyst; separating products of said reaction into a volatile product phase containing acetic acid and a less volatile phase; distilling said volatile phase in a distillation apparatus to obtain a purified product of acetic acid and a first overhead fraction containing methyl iodide and acetaldehyde; condensing at least a portion of said overhead fraction; measuring density of said condensed first overhead fraction; determining relative concentration of methyl iodide, acetaldehyde or both in the first overhead fraction based on the measured density; and adjusting at least one process control parameter associated with distillation of said volatile phase as a response reaction to said relative concentration. The invention relates to a method of producing acetic acid comprising the following steps: reacting methanol with carbon monoxide in a reaction medium containing water and methyl iodide in the presence of a group VIII metal based carbonylation catalyst; performing vapour-liquid separation in said reaction medium to obtain a vapour phase containing acetic acid, methyl iodide, acetaldehyde and water, and a liquid phase; distilling said vapour phase in a distillation apparatus to obtain a purified acetic acid product and at least a first overhead fraction containing acetaldehyde and methyl iodide; condensing said first overhead fraction; extracting said first overhead fraction with water to obtain a raffinate containing methyl iodide and an aqueous extract; measuring density of at least one stream selected from a group consisting of said first overhead fraction, said raffinate and said aqueous extract; determining relative concentration of methyl iodide, acetaldehyde or both in at least said first overhead fraction, said raffinate and said aqueous extract based on the measured density; and adjusting at least one process control parameter associated with either distillation of said vapour phase or extraction of said first overhead fraction as a response reaction to said relative concentration.

EFFECT: method of controlling the separation process in order to remove permanganate reduced compounds from a process stream during methanol carbonylation, involving steps of measuring density of a stream containing acetaldehyde and methyl iodide, and calculating relative concentration of acetaldehyde and methyl iodide in the stream enables to adjust parameters of the distillation or extraction process based on measured density or one or more relative concentrations calculated therefrom.

12 cl, 5 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to an improved method of producing acetic acid, involving (a) catalytic reaction of methanol or reactive derivative thereof with carbon monoxide in the presence of a group VIII metal based homogeneous catalyst and methyl iodide as a promoter in a reaction vessel which contains a liquid reaction mixture containing acetic acid, water, methyl acetate, methyl iodide and a homogeneous catalyst, wherein the reaction vessel operates at reactor pressure; (b) removing the reaction mixture from the reaction vessel and feeding the removed reaction mixture along with additional carbon monoxide into a pre-evaporation/post-reaction vessel operating at low pressure, which is below the pressure in the reaction vessel; (c) blowing light fractions in the pre-evaporation vessel and simultaneous consumption of methyl acetate in the pre-evaporation/post-reaction vessel to obtain a pre-evaporation mixture which is rich in acetic acid and is poor in methyl iodide and methyl acetate compared to the reaction mixture; (d) removing the pre-evaporation reaction mixture from the pre-evaporation/post-reaction vessel and feeding the pre-evaporation mixture into the evaporation vessel; (e) flash evaporation of the stream of raw acetic acid from the mixture in the evaporation vessel operating at pressure which is considerably lower than that of the pre-evaporation/post-reaction vessel; (f) recycling the residue after evaporation process from the evaporation vessel into the reaction vessel and (g) purifying the stream of the raw product. Low content of methyl iodide and methyl acetate in the formed stream of evaporated raw product eliminate the role of light fraction columns as the bottleneck of the scheme.

EFFECT: method increases efficiency of the process; eliminated the need for a high-pressure absorber, which reduces capital costs and operating costs.

24 cl, 1 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to a method of separating glyoxylic acid from an aqueous reaction medium which contains glyoxylic acid and hydrochloric acid, which involves a step of distilling the reaction medium in a counter-current with steam to obtain, on one hand, a gaseous phase which contains volatile hydrochloric acid and, on the other hand, a liquid phase which contains purified glyoxylic acid.

EFFECT: method enables to considerably reduce residual concentration of hydrochloric acid in the medium.

14 cl, 2 ex

FIELD: chemistry.

SUBSTANCE: present invention relates to a method of separating liquid phase by-products of Fischer-Tropsch synthesis, which involves the following steps: a) feeding the liquid phase by-products into a standard fractionation column (1) in its middle part with output of a portion of the stream I, having a boiling point range from 50 to 120°C, as a side cut to obtain light components having boiling point below 50°C from the top of the column, and heavy components, having boiling point higher than 120°C from the bottom of the column; b) feeding the stream I into a column (2) for separating acetic acid in its middle part to obtain a stream of aqueous solution II, containing alcohols and ketones, having boiling point range from 50 to 100°C from the top of the column, and a stream III of aqueous solution of acetic acid from the bottom of the column; and c) feeding the stream II into a column (3) for separating ethanol in its middle part to obtain a stream IV of a mixture of methanol and acetone from the top of the column and a stream V of aqueous solution of ethanol and n-propanol from the bottom of the column (see dwg 3).

EFFECT: high efficiency of the process.

9 cl, 4 dwg, 30 tbl, 30 ex

FIELD: chemistry.

SUBSTANCE: invention relates to improved carbonylation methods in order to produce acetic acid, the methods involving: (a) carbonylating methanol or reactive derivatives thereof in the presence of water, a catalyst selected from a group which includes rhodium catalysts, iridium catalysts and mixtures thereof, and methyl iodide as a promoter to form an acetic acid containing reaction mixture in the reactor; (b) separating the stream of the acetic acid containing reaction mixture into a liquid recycled stream and a crude product stream containing acetic acid, methyl iodide, methyl acetate and water; (c) feeding the crude product stream to a stripping column having a distillation zone; (d) purifying the crude product stream in the distillation zone of the stripping column to remove methyl iodide and methyl acetate and obtain a purified product stream, the purified product stream characterised lower concentration of methyl iodide and methyl acetate than the crude product stream, and wherein the step of purifying the crude product stream involves: (i) condensing overhead vapour from the distillation zone of the stripping column, (ii) decanting the condensed vapour to obtain a heavy phase mainly containing methyl iodide and a light phase mainly containing acetic acid and water, and (iii) refluxing at least a portion of the condensed heavy phase to the distillation zone of the stripping column; and (iv) recycling the light phase into the reactor; and (e) drawing a purified product stream from the stripping column.

EFFECT: content of acetic acid in the overhead vapour of the stripping column and content of water in the product stream of the stripping column (side cut) is reduced, which increases efficiency of purification.

17 cl, 3 dwg, 1 tbl

FIELD: chemistry.

SUBSTANCE: conducting heterogeneously catalysed gas-phase partial oxidation of at least one corresponding starting compound with three carbon atoms on catalysts in a solid aggregative state at high temperature with molecular oxygen enables to obtain a gaseous mixture of products containing acrylic acid, water vapour and secondary components; if necessary, temperature of said mixture is lowered by direct and/or indirect cooling, after which said mixture is fed into a condensation column equipped with efficiently separating elements, wherein said mixture rises by itself along said column with simultaneous flow of fractional condensation. Through a first side outlet, which lies above the point of feeding the gaseous mixture of reaction products into the condensation column, crude acrylic acid poor in water and secondary components is output from the condensation column as the end product; through a second liquid phase outlet lying above the first side outlet, acid water containing acrylic acid and secondary components is output from the condensation column; a residual gaseous mixture containing secondary components which boil at a lower temperature than water is output from the top part of the condensation column; still liquor which contains acrylic acid, as well as byproducts and secondary components which boil at higher temperature than acrylic acid are output the bottom of the condensation column; part of the amount of the collected acid water as it is and/or after cooling is returned into the condensation column as reflux, and crude acrylic acid is optionally subjected to additional treatment using at least another thermal separation method, and, if necessary, part of the amount of collected acid water is added to acrylic acid before additional crystallisation treatment, where acrylic acid contained in at least part of the amount acid water which is not returned into the condensation column is transferred from the acid water to an organic solvent through extraction carried out by said solvent, which is accompanied by formation of an organic extract containing acrylic acid, from which acrylic acid is further separated by stripping thereof with a first stripping gas, wherein the first stripping gas containing acrylic acid is returned into the condensation column, and/or acrylic acid contained in the first stripping gas is transferred into an aqueous solution of a metal hydroxide or the formed first stripping gas which contains acrylic acid is used as a second stripping gas in order to strip acrylic acid contained in the still liquor output from the condensation column, and wherein the formed second stripping gas containing acrylic acid is returned into the condensation column and/or acrylic acid contained in the second stripping gas is transferred into an aqueous solution of a metal hydroxide.

EFFECT: improved method.

21 cl, 6 ex

FIELD: chemistry.

SUBSTANCE: invention relates to improved carbonylation methods for producing acetic acid, one of which involves: (a) carbonylation of methanol or reactive derivative thereof in the presence of water, a catalyst selected from rhodium catalysts, iridium catalysts and mixtures thereof, a promoter from methyl iodide to form a reaction mixture with acetic acid in a reactor; (b) separating the stream of the reaction mixture with acetic acid into a liquid recirculation stream and a first stream of the crude product which contains acetic acid; (c) feeding the first stream of crude product into a column for distillation of light fractions; (d) distillation of the stream of crude product to remove low-boiling components as the overhead product and form a first stream of the purified product in form of a side stream and a liquid residual stream, the liquid residual stream primarily consisting of acetic acid, where the first stream of purified product is fed into a dehydration column, after which the dried product is fed into a column for distillation of heavy fractions, and acetic acid is collected in form of an overhead product from the column for distillation of heavy fractions; (e) evaporating at least a portion of the liquid residual stream to obtain a second product stream; and (f) feeding the second product stream after condensation or compression thereof for further processing after merging with the first stream of purified product into said dehydration column. The invention also relates to an apparatus for producing acetic acid, comprising: (a) a reactor for carbonylation of methanol or reactive derivatives thereof in the presence of water, a catalyst selected from rhodium catalysts, iridium catalysts and mixtures thereof, and a promoter from methyl iodide to form a reaction mixture with acetic acid in the reactor; (b) a flash evaporation apparatus connected to the reactor and configured for inlet of the stream of the reaction mixture and separation thereof into (i) a liquid recirculating stream and (ii) a crude first product stream containing acetic acid; (c) a column for distillation of light fractions, which is connected to the flash evaporation apparatus which is configured for separation of low-boiling components in form of an overhead product from the first product stream and formation of a first stream of purified product in form of a side stream, and a liquid residual stream; (d) a dehydration column connected to the column for distillation of light fractions; (e) a column for distillation of heavy fractions connected to the dehydration column; and (f) an evaporation reservoir, also connected to the column for distillation of light fractions, for evaporation of at least a portion of the liquid residual stream and configured to feed a second product stream into the dehydration column; or a column for distillation of the liquid residual stream to form a stream of the purified product and meant for feeding it into the dehydration column or into the column for distillation of heavy fractions, where the column for distillation of the liquid residual stream is a stripping column. The apparatus and methods of producing acetic acid thus involve extraction of the product from the residue of light fractions in a stripping column and feeding the extracted acid for further processing in order to increase efficiency of the system.

EFFECT: reduced load on the column for distillation of light fractions; the load on the dehydration column can also be reduced in the embodiment, wherein further removal of water from the extracted acid is not necessary.

15 cl, 4 dwg, 2 tbl

FIELD: chemistry.

SUBSTANCE: invention relates to methods of removing acetaldehyde from a mixture of methyl acetate, methanol and acetaldehyde, one of which involves: (a) feeding the mixture of methyl acetate, methanol and acetaldehyde into a rectification column; (b) rectification of the mixture of methyl acetate, methanol and acetaldehyde at pressure of 68.95 kPa (10 pounds/square inch) or higher to form a vapour stream output from the top of the column which is rich in acetaldehyde compared to the mixture, and a bottom residue poor in acetaldehyde compared to the mixture; (c) returning as reflux a portion of the vapour stream which is output from the top of the column into the rectification column; and (d) removing a stream of the bottom residue poor in acetaldehyde from the rectification column, where temperature of the vapour stream from the top of the column ranges from 85°C to 115°C. The invention also relates to a method of producing acetic acid, involving: (a) cleaning the mixture of methyl acetate, methanol and acetaldehyde with removal of acetaldehyde by: (i) feeding the mixture of methyl acetate, methanol and acetaldehyde into a rectification column; (ii) rectification of the mixture of methyl acetate, methanol and acetaldehyde at pressure of 68.95 kPa (10 pounds/square inch) or higher to form a vapour stream which is output from the top of the column which is rich in acetaldehyde compared to the mixture, and a bottom residue poor in acetaldehyde compared to the mixture; (iii) returning as reflux a portion of the vapour stream output from the top of the column into the rectification column; and (iv) removing a stream of the bottom residue poor in acetaldehyde from the rectification column; (b) feeding the cleaned stream of bottom residue into the reaction mixture for carbonylation together with carbon oxide, where the reaction mixture for carbonylation contains water, a catalyst selected from rhodium catalysts, iridium catalysts or mixtures thereof, a promoter from methyl iodide and acetic acid; and (c) extracting acetic acid from the carbonylation mixture, where temperature of the stream which is output from the top of the column ranges from 85°C to 115°C.

EFFECT: improved methods.

15 cl, 8 dwg, 6 tbl, 16 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a method of transferring heat to a liquid mixture containing at least one (meth)acrylic monomer selected from a group comprising acrylic acid, methacrylic acid, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, glycidyl acrylate, glycidyl methacrylate, methyl acrylate, methyl methacrylate, n-butyl acrylate, isobutyl acrylate, isobutyl methacrylate, n-butyl methacrylate, tert-butyl acrylate, tert-butyl methacrylate, ethyl acrylate, ethyl methacrylate, 2-ethylhexyl acrylate and 2-ethylhexyl methacrylate, through an indirect heat exchanger on whose primary side a fluid heat carrier flows and on whose secondary side simultaneously flows said liquid mixture containing at least one (meth)acrylic monomer, wherein the liquid mixture containing at least one (meth)acrylic monomer, in order to reduce contamination, additionally contains at least one active compound other than (meth)acrylic monomers which is selected from a group consisting of tertiary amines, salts formed from a tertiary amine and a Bransted acid, and quaternary ammonium compounds, under the condition that none of the tertiary and quaternary nitrogen atoms in the at least one active compound bears a phenyl group but at least some of said tertiary and quaternary nitrogen atoms bear at least one alkyl group.

EFFECT: improved method.

15 cl, 16 ex

FIELD: chemistry.

SUBSTANCE: invention relates to an improved method of producing acetic acid comprising the following steps: reacting methanol with carbon monoxide in a reaction vessel containing water, methyl iodide and methyl acetate in the presence of a group VIII metal based carbonylation catalyst; separating products of said reaction into a volatile product phase containing acetic acid and a less volatile phase; distilling said volatile phase in a distillation apparatus to obtain a purified product of acetic acid and a first overhead fraction containing methyl iodide and acetaldehyde; condensing at least a portion of said overhead fraction; measuring density of said condensed first overhead fraction; determining relative concentration of methyl iodide, acetaldehyde or both in the first overhead fraction based on the measured density; and adjusting at least one process control parameter associated with distillation of said volatile phase as a response reaction to said relative concentration. The invention relates to a method of producing acetic acid comprising the following steps: reacting methanol with carbon monoxide in a reaction medium containing water and methyl iodide in the presence of a group VIII metal based carbonylation catalyst; performing vapour-liquid separation in said reaction medium to obtain a vapour phase containing acetic acid, methyl iodide, acetaldehyde and water, and a liquid phase; distilling said vapour phase in a distillation apparatus to obtain a purified acetic acid product and at least a first overhead fraction containing acetaldehyde and methyl iodide; condensing said first overhead fraction; extracting said first overhead fraction with water to obtain a raffinate containing methyl iodide and an aqueous extract; measuring density of at least one stream selected from a group consisting of said first overhead fraction, said raffinate and said aqueous extract; determining relative concentration of methyl iodide, acetaldehyde or both in at least said first overhead fraction, said raffinate and said aqueous extract based on the measured density; and adjusting at least one process control parameter associated with either distillation of said vapour phase or extraction of said first overhead fraction as a response reaction to said relative concentration.

EFFECT: method of controlling the separation process in order to remove permanganate reduced compounds from a process stream during methanol carbonylation, involving steps of measuring density of a stream containing acetaldehyde and methyl iodide, and calculating relative concentration of acetaldehyde and methyl iodide in the stream enables to adjust parameters of the distillation or extraction process based on measured density or one or more relative concentrations calculated therefrom.

12 cl, 5 dwg

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