The method of purifying acetic acid and/or acetic anhydride from impurity iodides

 

(57) Abstract:

Usage: the technology of production of acetic acid and/or acetic anhydride by carbonyliron the carbon monoxide methanol or acetate. The inventive method of cleaning contaminated iodide fraction of carboxylic acid and/or anhydride obtained by liquid-phase carbonylation using carbonylation catalyst, IDataReader promoter and IDataReader of copromotor by evaporation of this fraction after cleaning it from the catalyst, the source material and the components of the promoter with getting in the steam fraction of the acid and/or anhydride with a lower content of impurities iodide. The products of the carbonylation served in the preliminary flash evaporator, is provided in the upper part of the scrubbing section, in which the distillate containing carbonylation catalyst and other impurities and unreacted raw materials derive from a bottom of the apparatus. The distillate is sent to the distillation column. VAT residue containing contaminated by impurities acetic acid, serves in the final flash evaporator, which emit vapor purified acetic acid. 6 C.p. f-crystals, 2 ill., table 4.

Acetic acid and acetic anhydride are known chemicals for many years used in industry. Acetic anhydride is the second largest area of application of acetic acid. It is widely used in obtaining cellulose acetate and other esters. His lesser number of going to get special esters, aspirin and pesticides. Acetic acid is used as a preservative, and as an intermediate in obtaining, for example, acetate esters.

Obtaining acetic acid by liquid-phase carbonylation of methanol is widely known industrial process, which is used in wide industrial scale. The carbonyl process, which is usually catalyzed by rhodium and idestam the stands, are described, for example, in the United Kingdom patent 1233121. In European patent A-0087870 described a modified method by which acetic anhydride together with or without acetic acid is obtained by successive stages of esterification, carbonyliron the methanol return acetic acid under esterification with the formation of the product of esterification, mainly containing methyl acetate, water, and possibly unreacted methanol;

2) removal of the water from the product of esterification;

3) the interaction of the product of esterification, still containing some water, and carbon monoxide under carbonylation in the presence of a catalyst of free or bound metal carbonylation catalyst and promoter of free or bound halogen, with the formation of the carbonylation product containing acetic acid and acetic anhydride;

4) separating the carbonylation product by fractional distillation at low-boiling fraction containing the original reaction mixture and the volatile components of the promoter carbonyl fraction of acetic acid and acetic anhydride and the high-boiling fraction containing components of the catalyst for the carbonylation;

5) reset the low-boiling fraction containing the original reaction mixture and the components of the carbonylation promoter, and the high-boiling fraction containing components of the catalyst, carbonylation, phase carbonylation;

6) returning at least part of the fraction of acetic acid through esterification.

Getting anhydrides carb is ecopassage carbonyl in particular, in accordance with the United Kingdom patent 1.233.021, European patent A-0087870 and U.S. patent 5.033.104 and 4.792.620, a preferred promoter is idatabase connection, preferably itorganize connection, for example, haloalkyl or halodrol, and most preferred is modesty methyl. In addition to these promoters can also be used iododerma copromotor, such as modestie Quaternary salts of heterocyclic amines described in European patent A-0391680, alkylated iodides imidazole described in European patent A-0379463, and lithium iodide as described in U.S. patent 5.003.104.

Product carbonyl containing carboxylic acid and/or anhydride, the initial reaction mixture, the catalyst for the carbonylation, idatabase the promoter, and which may also contain components IDataReader of copromotor, can be separated by passing through a first distillation column, the head fraction which contains the original reaction mixture and iododerma components of the promoter, the intermediate fraction contains carboxylic acid and/or anhydride, and the bottom fraction contains the catalyst and possibly components of copromotor. The goal is ay fractional distillation in the second distillation column into fractions carboxylic acid and its anhydride.

The disadvantage of the method described above carbonylation using IDataReader promoters and, optionally, iododerma of copromotion is that it allows for a carboxylic acid and/or their anhydrides, even after separation and purification can contain significant amounts of impurities iodide. In certain processes, such as the subsequent conversion of acetic acid to vinyl acetate, impurities iodine have unwanted effects, and it is highly desirable to remove them.

To some extent this disadvantage can be eliminated by passing the product of the carbonylation primarily through the evaporator equilibrium of the type in which a liquid fraction comprising carbonylation catalyst and possibly iododerma copromotor, is separated from the steam fraction comprising carboxylic acid and/or anhydride, the initial reaction mixture and the components IDataReader promoter. While the liquid fraction is returned to the carbonylation reactor and steam fraction is fed into the first distillation column, is modified so that the flowing product was separated only on the head fraction, excluding the initial reaction mixture is installed so acid and/or anhydride contain some impurities iodine, in many cases, is invalid.

It was found that the impurity content of iodide can be significantly reduced, if contaminated them a fraction of carboxylic acids, in particular acetic acid and/or its anhydride, obtained by liquid-phase carbonylation using IDataReader promoters and, optionally, iododerma of copromotion and purified from the carbonylation catalyst, the initial reaction mixture and the components IDataReader promoter and possibly iododerma of copromotion, subjected to evaporation, in which acetic acid and/or its anhydride with a lower content of impurities iodide is separated in the form of steam fraction from the liquid fraction.

The subject of the invention, therefore, is a method of cleaning contaminated iodide fraction of acetic acid and/or its anhydride, obtained by liquid-phase carbonyliron able to carbonyliron feedstock selected from the group comprising methanol, diethyl ether and/or methyl acetate, using a carbonylation catalyst, IDataReader promoter and, if desired, IDataReader of copromotor, by filing a product of liquid-phase carbonylation in predvaritel the carbonylation catalyst and, if necessary, idatabase copromotor, is separated from the steam fraction containing acetic acid and/or acetic anhydride, unreacted in the carbonyl process raw materials and components IDataReader promoter, specified liquid fraction is returned to the carbonylation reactor and steam fraction is sent to a distillation column in which the selected head fraction containing raw materials for the carbonylation and the promoter from the cubic residue containing contaminated iodide impurities acetic acid and/or acetic anhydride, with the specified VAT residue is sent to the destination flash evaporator, where acetic acid and/or acetic anhydride with reduced content of iodide-containing impurities, separated in the form of steam fraction from the liquid fraction.

Contaminated with iodide acetic acid and/or its anhydride are obtained by liquid-phase carbonylation able to carbonyliron feedstock using a catalyst, carbonylation, IDataReader promoter and, if desired, IDataReader of copromotor. The details associated with carbonyliron, catalysts, promoters and IDataReader copromotor can be found in the aforementioned patents Feofania feedstock includes methanol, diethyl ether and/or methyl acetate. Suitable carbonylation catalysts include the metals of group VII of the Periodic table of the elements, of which preferred are the noble metals, iridium, osmium, platinum, palladium, rhodium plated with ruthenium. Most preferred of these is rhodium. As IDataReader promoters can be used elemental iodine, modesty hydrogen, inorganic salts of iodine, such as iodide of sodium, potassium, lithium or cobalt, and the like, and Quaternary ammonium iodides or fofanah grounds.

Preferred, in particular, are organic iodides such as modesty alkyl or modesty aryl. Most preferred is modesty methyl.

As IDataReader of copromotor you can use the iodide of lithium, magnesium, calcium, titanium, chromium, iron, Nickel and aluminum, and most preferred is lithium iodide, or a Quaternary ammonium iodides or fofanah bases, such as, for example, modesty N, N ' - dimethylimidazole, or their predecessors. The use of suitable copromotion described in the above European patent A-0391680 And 0479463 and in U.S. patent 5.003.104. So, in the European patago from the group consisting of iodide Quaternary ammonium bases of the formula

< / BR>
< / BR>
< / BR>
where R and R1independently from each other selected from hydrogen or C1C20-alkyl, provided that at least R1does not mean a hydrogen atom.

In European patent A-0479463 described getting anhydrides of carboxylic acids using copromotor selected from the group consisting of iodotope 1,3-dialkyl-4-methylimidazole, iodotope 1,3-dialkyl-4-ethylimidazole, iodotope 1,3-dialkyl-4-n-propylimidazol, iodotope 1,3-dialkyl-1,4-isopropylimidazole, iodotope 1,3-dialkyl-4-n-butylimidazole, iodotope 1,3-dialkyl-4-sec.-butylimidazole, iodotope 1,3-dialkyl-4-tert. -butylimidazole, iodotope 1,3-dialkyl-2,4,5 - trimethylimidazo and mixtures thereof, where alkali independently from each other mean WITH1-C20-alkyl.

In U.S. patent 5.003.104 described carbonylation of methyl acetate in the presence of iodotope lithium as copromotor.

The preferred final evaporator equilibrium type is the evaporator equilibrium type without fractionation. Temperature, pressure and other operating parameters such evaporator is necessary for the separation of liquid to vapor is the fraction of carboxylic acid and/or anhydride, contaminated iodide. It is advisable that the pressure in the final evaporator equilibrium type in the process of working up to 106PA, preferably would be in the range of 0 to 0.15 106PA, and the temperature was equal to 100 200oC, preferably 1290 - 160oC. is preferable that the mass ratio between steam and liquid fractions in the process of the final evaporator equilibrium type was in the range of 0.5 to 100, preferably 5: 1 to 30:1. The specified evaporator equilibrium type can operate in the mode of "himself", when he is not fed a liquid fraction, and all steam fraction is returned to him as the source material. It is advisable that the residence time of the liquid in the final evaporator equilibrium type, calculated as the quotient of the mass of the liquid in it on the mass feed rate was up to 60 min, preferably would be in the range of 5 to 40 minutes

Heat to such evaporator equilibrium type can be fed in any way. Preferably, however, be used for this purpose pairs, feeding it, for example, using an external thermosyphon reboiler from steam shell, and the treated liquid from the tubes, in which she CLASS="ptx2">

According to the invention for the purification of acetic acid and/or its anhydride from carbonylation catalyst, the initial reaction mixture and iododerma components of promoter and possibly copromotor, the carbonylation product is sent to the pre-evaporator equilibrium of the type in which a liquid fraction comprising carbonylation catalyst and idatabase copromotor (if used), is separated from the steam fraction comprising acetic acid and/or its anhydride, the initial reaction mixture and the components IDataReader promoter. The liquid fraction is returned to the carbonylation reactor and steam fraction is sent to a distillation column in which the parent faction, including the original reaction mixture and idatabase the promoter is separated from VAT residue, including containing impurities iodide acetic acid and/or anhydride.

VAT residue containing contaminated iodide acetic acid and/or anhydride, then send in the final evaporator equilibrium type (flash evaporator), in which acetic acid and/or anhydride with a lower content of impurities iodide is separated in the form of steam fraction from the liquid fraction.

Another in snoosnoo type is made as a single unit together with the distillation column. In this case the cube distillation column plays the role of the capacity of the evaporator and the evaporation is carried out not by a separate heat source, and by reboiler distillation columns. In this embodiment, from the upper part of the column is removed faction, including the original reaction mixture and idatabase promoter. Steam fraction comprising acetic acid and/or anhydride is removed from the lower part of the distillation column. The concentration of iodide is lower than if from the bottom of the distillation column was assigned a liquid fraction. Waste liquid fraction is removed separately from the vapor fraction withdrawn from the bottom of the distillation column. In this embodiment, the steam fraction can be removed directly from the bottom of the distillation column above the liquid level in her cube or from the same through one or two plates to prevent entrainment of liquid. To reduce entrainment of liquid you can use any, are used for this purpose, the known methods.

Preferably next to the upper part of the preliminary evaporator equilibrium type was mounted scrubber section with mesh, nozzles, plates or other podobn is but a solvent, to dissolve the catalyst. Alternatively or additionally, in the upper part of the pre-evaporator equilibrium type can be placed nozzle to ensure distillation, for example, the grid. Preferably as washing liquid in the scrubber part of the pre-evaporator equilibrium type, use the liquid fraction separated in the final evaporator.

In the absence of the final evaporator equilibrium type, even when using pre-evaporator with scrubbing device and the nozzle of the braided mesh impurity content of iodide in acetic acid and/or acetic anhydride exceeds the allowable for a particular application values. In particular, this occurs in those cases when carbonyliron used iododerma copromotor. The reasons for this are unclear, and they can only guess. Perhaps, iodides, having a very high boiling point, are carried away together with the evaporation of the distillate in the form of a very thin mixture, and/or as a result of chemical transformations connected in series in the distillation column formed iodides. Whatever it was, but the fact remains that the resulting product can b contaminated iodide acid and/or anhydride, it is quite surprising that the product is subjected to additional equilibrium evaporation, substantially reducing the impurity content of iodide.

In a preferred variant of the subject of the present invention is a method for acetic anhydride with or without acetic acid from methanol and carbon monoxide, consisting of a number of successive stages of esterification, carbonylation and selection, including:

1) the interaction of methanol with the return in the cycle of acetic acid under esterification with the formation of the product of esterification, mainly containing methyl acetate, water, and possibly unreacted methanol;

2) removal of the product of esterification of the water;

3) the interaction of the product of esterification, containing some amount of water, as the source material with carbon monoxide under carbonylation in the presence of free or bound metal carbonylation catalyst, IDataReader promoter and, if desired, IDataReader of copromotor education in the carbonylation product containing acetic acid and/or acetic anhydride;

4) submission of product produced carbonyliron the iej, in which a liquid fraction comprising carbonylation catalyst, and possibly IDataReader copromotor, is separated from the steam fraction comprising acetic acid and/or acetic anhydride, carbonyliron unreacted raw materials and idatabase promoter;

5) the return of the liquid fraction from step (4) by fractional distillation in a distillation column for VAT residue, including contaminated iodide acetic acid and/or acetic anhydride, and the head fraction comprising unreacted under carbonylation source material and idatabase promoter;

7) return the head fraction from stage (6) for phase carbonylation;

8) submission of VAT residue from step (6), including contaminated iodide impurities acetic acid and/or acetic anhydride, in the final evaporator equilibrium type, in which acetic acid and/or acetic anhydride with low impurities content of iodide is separated in the form of steam fraction from the liquid fraction;

9) the return of the liquid fraction from step (8) as the wash liquid in the scrubber section of the pre-evaporator equilibrium type;

10) the separation by distillation of acetic acid from acetic anhydride from the stage of esterification (1);

12) the extraction of acetic anhydride and one part acetic acid, which is not returned to the stage of esterification, of the steam fraction from step (8).

Using a modified version of this method the final evaporator equilibrium type can be made as a whole from the fractional distillation column used for the fractional distillation of the product at the stage (6). In this case, stage (6) (9) is modified as follows:

6') the separation of the steam fraction from step (4) by fractional distillation in the distillation column to the main fraction comprising unreacted under carbonylation source material and idatabase promoter, cubic steam fraction comprising acetic acid and/or anhydride with a lower content of impurities iodide, and cubic liquid fraction;

7') return head fraction from step (6') on phase carbonylation;

8') challenging the bottom of steam and a bottom liquid fraction from the cube distillation columns;

9') return bottom liquid fraction from step (8') as wash liquid in the scrubber section of the pre-evaporator equilibrium type.

As already noted, to reduce ash cubic PA the current can be removed from the base of the distillation column.

Details on the preferred Regents, the reaction conditions and procedures in the implementation of this preferred variant implementation, contained in the previously mentioned European patent A-0087870.

In Fig. 1 depicts a simplified flow diagram of the relevant part of the way to obtain acetic anhydride and acetic acid from methanol and carbon monoxide, comprising the stages of esterification, carbonylation and selection, as described in European patent A-0087870; Fig. 2 is a modified construction of the apparatus depicted in Fig. 1, the evaporator is made as a unit with the distillation column.

According to the scheme in accordance with Fig. 1 the reaction product of the carbonylation, consisting mainly of acetic anhydride, acetic acid, unreacted methyl acetate, rhodium carbonylation catalyst, a certain amount of promoter is methyl iodide, and perhaps copromotor, for example, N, N'-dimethylimidazolidine coming out of the carbonylation reactor 15, is supplied by pipeline 1 in the pre-evaporator equilibrium of type 2, which includes scrubbing the plates 3 and input to the recirculated liquid 4. In addition to the Oh of the acid, unreacted methyl acetate and promoter under the conditions, is removed from the pre-evaporator equilibrium type pipe 5, and a liquid fraction comprising the non-volatile catalyst for carbonylation and possibly copromotor via the pipeline 6 and returned to the carbonylation reactor 15. Scrubbing plates 3, the nozzle woven mesh 14 and rinsing liquid 4, therefore, are intended to facilitate the removal of non-volatile iodides in the liquid fraction that is output through the pipeline 6.

Removed from the pre-evaporator equilibrium type 2 steam fraction in the pipe 5 is supplied to a distillation column 7, from the upper part of which the pipe 8 is given a fraction containing mainly unreacted methyl acetate and promoter-modesty methyl returned to the stage carbonylation. From cube 9 columns on the pipeline 10 is diverted waste liquid fraction, consisting mainly of contaminated iodide acetic anhydride and acetic acid.

From distillation column 7 waste fraction in the pipeline 10 is fed in the final evaporator equilibrium type 11, which is heated using an external thermosyphon reboiler 16 steam fed is Noah acid with a substantially lower content of iodide. The liquid phase is removed from the evaporator through the pipe 13 and is returned as a wash liquid on a plate 3 of the provisional evaporator equilibrium of type 2, in which it acts on input line 4.

Vapor phase withdrawn from the evaporator 11, is separated by distillation in the distillation column (not shown) in acetic anhydride and acetic acid. Acetic acid is returned, as described in European patent A-0087870 in the process. Part of it is used to obtain the acetate, is fed into the esterification reactor.

In Fig. 2 shows a modified variant of the installation according to Fig. 1, in which the target evaporator equilibrium type is made as a single unit together with the distillation column. All other elements of the installation are the same as in Fig. 1.

During operation of the product produced under carbonylation and States mainly of acetic anhydride, acetic acid, unreacted methyl acetate, rhodium carbonylation catalyst of a number of promoter iodotope bromide and possibly copromotor, for example, iodotope N,N'-dimethylimidazole, after the carbonylation reactor 15 podaa the La recirculated liquid. In addition, it has a nozzle woven mesh 14. Steam fraction consisting of acetic anhydride, acetic acid, unreacted methyl acetate and promoter iodotope bromide, is removed from the pre-evaporator equilibrium type pipe 5, and a liquid fraction comprising the non-volatile catalyst for carbonylation and possibly copromotor and the pipe 6 and is returned to the carbonylation reactor 15. Scrubbing plates 3, the nozzle woven mesh 14 and rinsing liquid 4 are intended to facilitate the removal of non-volatile iodides in the vapor fraction withdrawn through pipeline 6.

Steam fraction from the evaporator equilibrium of type 2 is fed by a pipe 5 to a distillation column 7, from the upper part of which the pipe 8 is given a fraction containing mainly unreacted methyl acetate and promoter modesty methyl returned to the stage carbonylation.

In depicted in Fig. 2 the schema of the target evaporator equilibrium type 2 is made as a unit with the distillation column. Thus, the cube 17 distillation column 7 plays the role of the finite capacity of the evaporator of the equilibrium type. Evaporation in this case is given postacie boiling the contents of the distillation column.

From the cube 17 distillation column through the pipeline 12 is given a steam fraction of acetic anhydride and acetic acid, with a significantly lower content of iodide than if from the cube distillation columns were selected liquid fraction. The liquid fraction is removed from the cube 17 through the pipe 13 and as a wash liquid is returned to the plates 3 of the provisional evaporator equilibrium of the type in which it is introduced through the inlet 4. Steam fraction may also be discharged from the cube distillation column through one or two plates.

Exhaust from the cube 17 to the pipe 12 steam fraction is separated by distillation in the distillation column (not shown) in acetic anhydride and acetic acid, and acetic acid is returned to the process as described in European patent A-0087870. Part of the separated acetic acid is used to obtain the acetate in the reactor at the stage of esterification.

P R I m e R s 1 and 2.

In these examples was used technological scheme similar to the scheme shown in Fig. 1.

Liquid composition, which is a product catalyzed by rhodium reaction carbonyldiimidazole, carried out in a reactor with a stirrer, operating in the continuous mode, was passed through the pre-evaporator equilibrium type. Removed from a liquid phase consisting of non-volatile rhodium carbonylation catalyst and iodotope N,N'-dimethylimidazole, returned to the carbonylation reactor. Exhaust from the pre-evaporator equilibrium type steam fraction was fed to the distillation column. Withdrawn from the upper part of the distillation column fraction comprising methyl acetate and promoter - modesty methyl, returned to the carbonylation reactor. The liquid fraction withdrawn from Cuba distillation column, cooled and collected in the vessel, after which he served in a heated steam evaporator operating at a pressure of 1 bar and a temperature of about 149oC. the Composition of the source material, steam and liquid fractions for examples 1 and 2 are given in table. 1 and 2.

From the above table. 1 and 2 data shows that the impurity content of iodide in the steam fraction is significantly lower than in the source material, and this, despite the fact that the latter has already been subjected to a preliminary treatment by evaporation.

P R I m e R s 3 and 4.

In these examples, ispolzovalas is based on a product catalyzed by rhodium carbonylation reaction of a mixture of methanol, methyl acetate and water in the presence of promoter-iodotope bromide and copromotor N,N'-dimethylimidazole carried out in a reactor with a stirrer, operating in the continuous mode, was passed through the pre-evaporator equilibrium type. Removed from a liquid fraction consisting of non-volatile rhodium carbonylation catalyst and iodotope N, N'-dimethylimidazole, returned to the carbonylation reactor. Exhaust from the pre-evaporator equilibrium type steam fraction was fed to the distillation column Oldrshaw 3 inch diameter, operating at atmospheric pressure. Withdrawn from the upper part of the distillation column vapor fraction comprising methyl acetate and promoter modesty methyl, returned to the carbonylation reactor. Steam fraction comprising acetic acid and acetic anhydride with low impurity content iodide, played with the second bottom plate distillation column. Waste liquid fraction was allocated from the cube distillation column and returning to the pre-evaporator equilibrium type. In example 3, distillation columns worked with returning phlegmy in the upper part of the column with the ratio between phlegm and select the parent faction 1,94 in table. 3 and 4. Low levels of iodide in the vapour fraction and a high content in distillation fractions shows that the iodide content in the vapour fractions lower than in the case if the flow of the mixture of acid and anhydride selected from the cube distillation columns in the form of liquid fraction.

1. The method of purifying acetic acid and/or acetic anhydride from impurity iodides in the process of liquid-phase carbonylation of the corresponding raw material selected from the group consisting of methanol, diethyl ether and methyl acetate using a catalyst, carbonylation, IDataReader promoter and optionally IDataReader of copromotor, characterized in that the product of liquid-phase carbonylation send in preliminary flash evaporator in which the liquid fraction, containing carbonylation catalyst and, if necessary, idatabase copromotor, is separated from the steam fraction containing acetic acid and/or acetic anhydride, unreacted in the carbonyl process raw materials and components IDataReader promoter, specified liquid fraction is returned to the carbonylation reactor and steam fraction is sent to a distillation column in which the selected head fra is installed iodide impurities acetic acid and/or acetic anhydride, send in the final flash evaporator, where acetic acid and/or acetic anhydride containing a low content of iodide-containing impurities, is separated from the liquid fraction in the form of steam fraction.

2. The method according to p. 1, characterized in that as the end of the flash evaporator is used, the evaporator flash evaporation without fractionation.

3. The method according to p. 1, characterized in that the end use of the flash evaporator, made in the form of a single whole with the distillation column by means of which steam fraction from the pre-flash evaporator is sent to a distillation column, from the top of which divert the head fraction containing feedstock for carbonylation and idatabase promoter, and steam fraction containing acetic acid and/or acetic anhydride, away from the cube distillation column separately from the liquid VAT residue that is removed from the base of the distillation column.

4. The method according to one of paragraphs.1-3, characterized in that the target evaporator support overpressure up to 106PA and/or temperature in the range of 100 to 200oC.

5. The method according to any of paragraphs.1-4, characterized in that the pre-flash will evaporate is the quality of the rinsing liquid.

6. The method according to any of paragraphs.1-5, characterized in that carbosilane raw material for the formation of acetic acid and acetic anhydride is carried out in the presence of a rhodium catalyst, under the conditions as promoter and NN'-dimethylimidazolidine as copromotor.

7. The method according to any of paragraphs.1-6, wherein the carbonylation product is obtained using the stages of esterification, carbonylation and separation from the liquid phase, including the interaction of methanol with recycled acetic acid under esterification with the formation of the product of esterification, containing mainly methyl acetate, water) and do not necessarily unreacted methanol, removal of the water from the product etherification, the interaction product of esterification, containing some amount of water, as carbonyliron raw materials with carbon monoxide under carbonylation in the presence of free or bound metal carbonylation catalyst, IDataReader promoter and not necessarily IDataReader of copromotor, with the formation of the carbonylation product containing acetic acid and acetic anhydride, characterized in that the product of the carbonylation sing the liquid fraction, containing carbonylation catalyst and do not necessarily idatabase copromotor from steam fraction containing acetic acid, acetic anhydride, carbonyliron unreacted raw materials and idatabase promoter, the separated liquid fraction is returned to the step carbonylation, and steam fraction separated by fractional distillation in a distillation column, taking the head fraction containing unreacted under carbonylation feedstock and idatabase promoter, which return to the stage carbonyl and VAT residue containing contaminated iodide impurities acetic acid and acetic anhydride, served in a final flash evaporator, which steam fraction is separated acetic acid and acetic anhydride are already low in iodide-containing impurities from the liquid fraction is returned to the scrubber section of the pre-evaporator as wash liquid.

 

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1 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to method of obtaining acetic acid, which includes: (a) carbonylation of methanol in presence of catalyst to form reaction mixture; (b) instant evaporation and distillation of reaction mixture in evaporator, equipped with distillation column to form liquid flow, including catalyst, from evaporator boiler, and steam flow from upper part of distillation column, and (c) return of liquid flow into the cycle to stage (a), with steam flow being distilled in stripping column to form bottom flow of raw acetic acid and flow of distillate steam, which is condensed and separated into light phase and heavy phase, part of light phase is introduced into the top part of evaporator distillation column, and liquid flow is withdrawn from the bottom of evaporator distillation column and directed to the top of stripping column to obtain practically pure acetic acid.

EFFECT: increased method efficiency.

11 cl, 2 dwg, 2 ex

FIELD: chemistry.

SUBSTANCE: methanol regeneration method involves preheating a water-methanol solution, evaporating vapour of the water-methanol mixture by mixing with heated vapour containing water vapour, fractionating the vapour of the water-methanol mixture to separate methanol and the steam condensate. The water-methanol solution is heated with methanol vapour during condensation thereof in the fractionation apparatus, as well as the balance part of the steam condensate removed from the apparatus. The water-methanol mixture is evaporated in hydrocyclone separators in two steps with premixing of the water-methanol solution with water vapour before the first separation step, as well as isoenthalpic evaporation at the second separation step. Fractionation is carried out at low pressure in a three-section falling film fractionation column.

EFFECT: simple method, low metal consumption and continuity of the regeneration process.

1 dwg, 1 ex

Separation method // 2571146

FIELD: chemistry.

SUBSTANCE: inventions can be used in chemical and energy fields, as well as in field of organic wastes recycling. Device for separation of ammonia from fermentation liquids or fermentation residues on installations for biogas production includes flash evaporator F, connected with fermenter (a) or with storage place of fermentation residues, for substrate supply by pipes (1, 2, 3, 4, 5, 6). Vapour from flash evaporator F is discharged, and hot liquid phase from pipelines (7, 8, 9) is either returned by pipeline (11) into fermenter A or to storage place of fermentation residues, or supplied by pipeline (10) into second fermenter (I), to storage place of fermentation residues or into additional reservoir. Admixture compartment, connected with heat-exchanger D for liquid substrate components from one side, and by pipeline (22) with the second fermenter I for solid substrate components, from the other side, is provided in pipeline (2, 3) from fermenter A.

EFFECT: inventions make it possible to increase exploitation stability, oxidative capacity and output of methane on installation for biogas production, as well as to reduce heat-productivity of the process.

10 cl, 2 dwg

FIELD: oil and gas industry.

SUBSTANCE: crude oil distillation method comprises the following stages: i) hydrocarbon crude oil is directed into a preliminary flash evaporation vessel maintained under conditions that allow crude oil separation into liquid resulting from the preliminary flash evaporation and vapour generated from the preliminary flash evaporation, ii) the liquid resulting from the preliminary flash evaporation is directed into a furnace maintained under conditions that provide heating and partial vaporization of the said liquid, iii) from the furnace, the heated flow is directed into the bottom of the atmospheric distillation column maintained under fractionation conditions; iv) the vapour resulting from the preliminary flash evaporation is directed into the area of the said distillation column located at the bottom of the stripping area located below the introduction area of flow coming from the furnace, and v) the water vapour is directed into the area of the said distillation column located at the bottom of stripping area so that the liquid flow coming from the furnace is contacted with the water vapour, and the vapour resulting from the preliminary flash evaporation, in the stripping area under conditions sufficient to strip liquid flow coming from the furnace, and the said vapour resulting from prior flash evaporation contains not more than 30 wt % of water and/or water vapour.

EFFECT: reduced amount of used water vapour.

8 cl, 1 dwg

FIELD: industrial inorganic synthesis.

SUBSTANCE: process is accomplished by continuously feeding methanol and/or reactive derivative thereof and carbon monoxide into carbonylation reactor filled with reaction mixture containing iridium carbonylation catalyst, methyl iodide cocatalyst, water in limited concentration, acetic acid, and methyl acetate, liquid reaction mixture further including at least one promoter selected from ruthenium, osmium, rhenium, and tungsten. Carbonylation of methanol to produce acetic acid involves reaction with carbon monoxide in liquid reaction mixture. When recovering acetic acid from liquid reaction mixture, concentration of water is maintained therein not exceeding 4.5%. During reaction, partial pressure of carbon monoxide in reactor is maintained within a range between 0 and 6 bar.

EFFECT: accelerated carbonylation reaction, diminished by-product formation, and simplified acetic acid recovery operation.

6 dwg, 3 tbl

FIELD: chemical industry; production of synthesis gas, methanol and acetic acid on its base.

SUBSTANCE: the invention is dealt with the methods of production of synthesis gas, production of methanol and acetic acid on its base. The method of upgrading of the existing installation for production of methanol or methanol/ ammonia provides for simultaneous use of the installation also for production of acetic acid or its derivatives. The existing installation contains a reformer, to which a natural gas or other hydrocarbon and a steam (water), from which a synthesis gas is formed. All the volume of the synthesis gas or its part is processed for separation of carbon dioxide, carbon monoxide and hydrogen. The separated carbon dioxide is fed into an existing circuit of synthesis of methanol for production of methanol or is returned to the inlet of the reformer to increase the share of carbon monoxide in the synthesis gas. The whole volume of the remained synthesis gas and carbon, which has not been fed into the separator of dioxide, may be transformed into methanol in the existing circuit of a synthesis of methanol together with carbon dioxide from the separator and-or carbon dioxide delivered from an external source, and hydrogen from the separator. Then the separated carbon monoxide is subjected to reactions with methanol for production of acetic acid or an intermediate compound of acetic acid according to the routine technology. A part of the acetic acid comes into reaction with oxygen and ethylene with formation of monomer of vinyl acetate. With the help of the new installation for air separation nitrogen is produced for production of additional amount of ammonia by the upgraded initial installation for production of ammonia, where the separated hydrogen interacts with nitrogen with the help of the routine technology. As the finished product contains acetic acid then they in addition install the device for production of a monomer of vinyl acetate using reaction of a part of the acetic acid with ethylene and oxygen. With the purpose of production of the oxygen necessary for production of a monomer of vinyl acetate they additionally install a device for separation of air. At that the amount of nitrogen produced by the device of separation of air corresponds to nitrogen demand for production of additional amount of ammonia. The upgraded installation ensures increased production of additional amount of ammonia as compared with the initial installation for production of methanol. The invention also provides for a method of production of hydrogen and a product chosen from a group consisting of acetic acid, acetic anhydride, methyl formate, methyl acetate and their combinations, from hydrocarbon through methanol and carbon monoxide. For this purpose execute catalytic reforming of hydrocarbon with steam in presence of a relatively small amount of carbon dioxide with formation of the synthesis gas containing hydrogen, carbon monoxide and carbon dioxide, in which synthesis gas is characterized by magnitude of the molar ratio R = ((H2-CO2)/(CO+CO2)) from 2.0 up to 2.9. The reaction mixture contains carbon monoxide, water -up to 20 mass %, a dissolvent and a catalytic system containing at least one halogenated promoter and at least one rhodium compound, iridium compound or their combination. The technical result provides, that reconstruction of operating installations increases their productivity and expands assortment of produced industrial products.

EFFECT: the invention ensures, that reconstruction of operating installations increases their productivity and expands assortment of produced industrial products.

44 cl, 3 ex, 6 dwg

FIELD: chemical technology.

SUBSTANCE: invention relates to a method for removing higher organic iodides from organic media. Method for removing organic iodides containing 10-16 carbon atoms from non-aqueous organic media containing organic iodides with 10-16 carbon atoms is carried out by contacting indicated organic media with silver- or mercury-exchange cationic, ion-exchange substrate at temperature from 50°C to 150°C. Invention proposes a method for removing iodides having 10-16 carbon atoms from acetic acid or acetic anhydride by providing flow of acetic acid or acetic anhydride containing organic iodide having 10-16 carbon atoms. Indicated flow is contacted with macroporous strong acid ion-exchange resin wherein at least 1% of active sites acquire form of silver or mercury at temperature in the range 50°C - 150°C. Indicated silver- or mercury-exchange ion-exchange resin removes effectively at least 90 wt.-% of indicated organic iodides from indicated flow of ready acetic acid or acetic anhydride. Also, invention proposes a method for removing organic iodides containing 10-16 carbon atoms from acetic acid or acetic anhydride involving contact of acetic acid or acetic anhydride comprising dodecyl iodide with silver- or mercury-exchange cationic ion-exchange substrate at temperature in the range 50°C - 150°C. Method provides the complete removing higher organic iodides from flow of acetic acid and/or acetic anhydride.

EFFECT: improved method for removing.

29 cl, 5 dwg, 13 ex

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to technology for manufacturing acetic acid by the carbonylation reaction of methanol with carbon monoxide. Method is carried out in the continuous regimen in the carbonylation reactor wherein methanol and carbon monoxide are fed and catalytically active rhodium-comprising catalyst medium is maintained wherein this medium comprises the following components: water, 0.1-14 wt.-%; methyliodide, 1-20%; alkaline metal iodide salt, 2-20%; methyl acetate and acetic acid, 0.5-30%. The total pressure value in reactor is 15-40 atm. Flow of the reaction products is subjected for rapid evaporation and fed to the distillation stage comprising up to two distillation columns wherein purified acetic acid is separated and some flows recirculating into reactor. Removal of iodide impurities from the final product is carried out by contacting the flow with anion-exchange resin at temperature 100°C, not less, followed by purification stage with sulfocation-exchange resin in form of silver or mercury salt comprising 1% of active sites, not less, at temperature 50°C, not less. The level of aldehyde impurities in the flow recirculating into reactor is regulated by the distillation off method. The content of iodides in acetic acid is less 10 parts/billion. Method provides decrease of energy consumption and preparing acetic acid of high purity degree.

EFFECT: improved producing method.

28 cl, 3 tbl, 7 dwg, 12 ex

FIELD: chemical technology.

SUBSTANCE: invention relates to continuous method for production of acetic acid and/or methyl acetate based on known process of methanol or derivatives thereof (such as dimethyl ether, halogenated methyl or methyl acetate) carbonylation. Process is carried out in homogenous liquid phase under carbon monoxide pressure in presence of catalytic system containing rhodium-based homogeneous catalyst and halogenated promoter, in presence of water in reaction medium and in amount of not less than 14 mass %. In continuous process homogeneous catalyst composition is gradually changed by continuous or discontinuous addition of any iridium compound. Catalyst composition is transformed without process shutdown by transition from rhodium-based catalyst to rhodium/iridium-based catalyst or iridium-based catalyst. Iridium addition makes it possible to decrease water content in reaction system.

EFFECT: modified industrial process of methanol carbonylation by transformation of catalytic system.

19 cl, 7 tbl

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