Method of oxidising alkane, method of obtaining alkyl-carboxylate and alkenyl-carboxylate with isolation of alkenes by absorption method, method of obtaining vinyl-acetate with isolation of ethylene by absorption method

FIELD: chemistry.

SUBSTANCE: invention relates to method of oxidising alkane from C2 to C4 with the obtaining of corresponding alkene and carboxylic acids. The method includes the following stages: (a) contact in the oxidation reaction zone of the alkane, which contains molecular oxygen gas, not necessarily corresponding to the alkene and not necessarily water in the presence of at least one catalyst, effective with the oxidation of the alkane to the corresponding alkene and carboxylic acid, alkane, oxygen and water; (b) separation in the first separating agent at least part of the first stream of products in a gaseous stream, which includes alkene, alkane and oxygen, and a liquid stream, which includes carboxylic acid; (c) contact of the mentioned gaseous stream with the solution of a salt of metal, capable of selectively chemically absorbing alkene, with the formation of a liquid stream rich in chemically absorbed alkene; (d) isolation from the flow of the solution of salt of the metal. The invention also relates to combined methods of obtaining alkyl-carboxylate or alkenyl-carboxylate (for example vinyl acetate), moreover these methods include oxidising of alkane from C2 to C4 with the obtaining of corresponding alkene and carboxylic acid, isolation of alkene from the mixture of alkene, alkane and oxygen by absorption using the solution of the salt of metal and extraction of the stream rich in alkene from the solution of the salt from metal for using when obtaining alkyl-carboxylate and alkenyl-carboxylate.

EFFECT: improved method of oxidising alkane from C2 to C4 with the obtaining of corresponding alkene and carboxylic acids.

46 cl, 1 dwg

 

The present invention relates to the separation of alkenes from gas mixtures comprising these alkenes, alkanes and oxygen, in particular to the separation of ethylene from a mixture of ethylene, ethane and oxygen absorption by a solution of the metal salt.

The present invention relates also to the application of the allocation method (a) in the oxidation of hydrocarbons such as alkane oxidation with2With4with the receipt of the corresponding alkene and carboxylic acid, and (b) in the combined processes in which the alkene and carboxylic acid derived from the oxidation of hydrocarbons, in the future use as reagents.

Ethylene and acetic acid can be obtained by catalytic oxidation of ethane. In a typical oxidation process of obtaining ethylene and acetic acid in the reactor is injected ethane, oxygen and optionally ethylene and/or water. These reagents is introduced into contact with the oxidation catalyst, such as molybdenum/niobium/vanadium-containing catalyst, and they interact with the formation of the exit stream comprising ethylene (either as a product or as unreacted starting material), acetic acid, unreacted ethane and unreacted oxygen. Coming out of the reactor flow away, condensed and separated into a gaseous stream and a liquid stream. A gaseous stream comprising ethane, ethylene and sarod, can be further purified with the receipt from him of ethylene. Liquid stream comprising acetic acid and water, can also be further purified.

It is known that the separation of ethylene from hydrocarbons, such as ethane, can be done by conducting distillation processes such as cryogenic distillation, and adsorption methods, such as adsorption with "swinging" pressure adsorption and reaction. In addition, when albanova/Allenova gas mixture includes oxygen, in particular gas mixture, the resulting oxidative dehydrogenation of ethane to ethylene as described, for example, in EP-A 0262264, before separation of the alkene from alkane traditionally remove oxygen. If before the separation of these hydrocarbons oxygen is not removed in the separation process can koncentriruetsa oxygen, resulting in oxygen-containing stream becomes inflammable or explosive.

In EP-A 0943595 described the method of allocation alkene, such as ethylene from a gas mixture comprising alkene and alkane, such as ethane, absorption process with "swinging" pressure, including the stage of passing the gas mixture through the zeolite type a, containing the capability to exchange sodium and potassium ions, and regenerating the zeolite with getting alkene-enriched gas. Such a system for adsorption with "swinging" pressure evsetbalance complex, and for one cycle of adsorption reach only a small increase in the concentration of ethylene. On the allocation of alkenes from gas mixtures, including alkenes, alkanes and oxygen, it doesn't say anything.

In WO 00/37399 describes how autothermal cracking of paraffin hydrocarbons with oxygen, and in this way the resulting stream comprises ethylene, propene, butene and carbon monoxide. Ethylene and propene isolated from the flow generated by the introduction of the stream into contact with a solution of a metal salt capable of selectively absorb ethylene and propene, and of the metal salt Recuperat ethylene and/or propene. Before treatment with a solution of a metal salt of the resulting stream is treated to remove components such as oxygen and carbon dioxide.

The products of the catalytic oxidation of ethane, ethylene and acetic acid in the subsequent processes can be entered in response to receipt of alkylcarboxylic, such as ethyl acetate, or alkenylboronic, such as vinyl acetate.

In view of the above, there is a need to develop alternative and/or improved method of separation of alkenes from a gas mixture comprising mentioned alkenes, alkanes and oxygen.

When creating the present invention, it was found that the alkene can be distinguished from a gas mixture comprising mentioned ALK is n, alkane and oxygen, without the need for prior removal of oxygen.

In addition, when creating the present invention it was found that the separation of the alkene from a gas mixture comprising the said alkene, alkane and oxygen, can be carried out by implementing fewer processing stages than were required in the known methods.

Accordingly, the present invention proposes a method of allocating alkene from a gas mixture comprising the said alkene, alkane and at least a 0.1 mol.% oxygen, and this method includes the following stages:

(a) contacting a specified gas mixture with a solution of a metal salt capable of selectively chemically absorbing alkene, to form a liquid stream rich in chemically absorbed by alkene;

(b) isolation of alkene from a solution of metal salt.

The advantage of the method according to the present invention is that its implementation avoids the need for expensive and energy-intensive equipment for the distillation separation.

Moreover, the implementation of the method according to the present invention eliminates or at least reduces the need for expensive refrigeration equipment.

An even greater advantage of the method according to the present invention is that its implementation allows you to safely separate alcenat alkane in the presence of oxygen.

The method according to the present invention is particularly effective in the allocation of alkene from alkanes, when shared alkene and alkane contain the same number of carbon atoms.

The method according to the present invention is particularly effective in the allocation of ethylene from gaseous mixtures containing ethylene, ethane and oxygen.

In the method according to the present invention in a preferred embodiment, alkane is an alkane with C2With4or mixtures thereof, such as ethane, propane, butane and mixtures thereof.

In a preferred embodiment, the alkene is an alkene with2With4or mixtures thereof, such as ethylene, propene, butenes and mixtures thereof.

The concentration of oxygen contained in the gas mixture is at least 0,1 mol.%, in particular at least 0.2 mol.%. Suitable oxygen concentration in the gas mixture is in the range from 0.1 mol.% to the concentration at which the gas mixture composition is below the range of Flammability. The oxygen concentration in the mixture should be such that rich alkanes formed thread is also non-flammable. In General, specialists in the art it is known that the limit of the range Flammability partially depends on the pressure and temperature of the mixture. When implementing the method according to the present invention the gas mixture composition is not what it should be in the range of Flammability at any stage of this method. The process of separating gases can effectively be carried out in such a way that the gas mixture composition was as close as possible to the range of Flammability, remaining nevertheless flammable.

Suitable oxygen concentration in the gas mixture is from 0.1 to 10 mol.%, in particular from 0.2 to 8 mol.%, for example, from 0.2 to 6 mol.%.

The allocation method of the present invention is particularly applicable to the threads formed in chemical processes. Thus, the method according to the present invention is particularly effective in the allocation of alkenes from the gas mixture of alkenes, alkanes and oxygen, which is formed due to oxidation of the alkane with C2With4.

Accordingly, an object of the present invention is a method of alkane oxidation with2With4the corresponding alkene and carboxylic acid, and this method includes the following stages:

a) contacting in an oxidation reaction zone specified alkane containing molecular oxygen gas, not necessarily corresponding alkene and optionally water, in the presence of at least one catalyst effective for the oxidation of the alkane to the corresponding alkene and carboxylic acid, to obtain a first product stream comprising alkene, carboxylic acid, alkane, oxygen and water;

(b) separation lane is Ohm separation means at least part of the first product stream in a gaseous stream, comprising alkene, alkane and oxygen, and a liquid stream comprising carboxylic acid;

(C) contacting mentioned gaseous stream with a solution of a metal salt capable of selectively chemically absorbing alkene, to form a liquid stream rich in chemically absorbed by alkene;

(g) isolation of the salt solution of the metal-rich alkene stream.

The method according to the present invention is also particularly effective when the alkene and/or carboxylic acid as products of the oxidation process is at least partly used in the United subsequent processes, such as (a) to obtain a complex ester by the reaction of carboxylic acid with an alkene or alcohol, or (b) to receive alkenylboronic reaction of oxygen-containing gas with a carboxylic acid and alkene. Alkene and/or carboxylic acid can be distinguished from the product of the oxidation reaction zone and/or additional amounts of the alkene and/or carboxylic acids can be used in a subsequent process.

Accordingly, an object of the present invention is a combined method of obtaining alkylcarboxylic, and this method includes the following stages:

(a) contacting in an oxidation reaction zone alkane containing molecular oxygen gas, not necessarily corresponding alkene and optionally the odes in the presence of at least one catalyst, effective in the oxidation of the alkane to the corresponding alkene and carboxylic acid, to obtain the first non-flammable product stream comprising alkene, carboxylic acid, alkane, oxygen and water;

(b) separating in a first separation means at least part of the first product stream in a gaseous stream comprising alkene, alkane and oxygen, and a liquid stream comprising carboxylic acid;

(C) contacting at least part of the aforementioned gaseous stream with a solution of a metal salt capable of selectively chemically absorbing alkene, to form a liquid stream rich in chemically absorbed by alkene;

(g) isolation of the salt solution of the metal-rich alkene stream and

(e) contacting the second reaction zone at least part of this rich alkene stream from step (g) and carboxylic acid in the presence of at least one catalyst effective upon receipt of alkylcarboxylic, with obtaining the specified alkylcarboxylic.

In addition, in another embodiment, the object of the present invention is a combined method of obtaining alkenylacyl, and this method includes the following stages:

(a) contacting in an oxidation reaction zone alkane containing molecular oxygen gas, not necessarily corresponding to Lena and optionally water, in the presence of at least one catalyst, effective in the oxidation of the alkane to the corresponding alkene and carboxylic acid, to obtain the first non-flammable product stream comprising alkene, carboxylic acid, alkane, oxygen and water;

(b) separating in a first separation means at least part of the first product stream in a gaseous stream comprising alkene, alkane and oxygen, and a liquid stream comprising carboxylic acid;

(C) contacting at least part of the aforementioned gaseous stream with a solution of a metal salt capable of selectively chemically absorbing alkene, to form a liquid stream rich in chemically absorbed by alkene;

(g) isolation of the salt solution of the metal-rich alkene stream and

(e) contacting the second reaction zone at least part of this rich alkene stream obtained in stage (d), carboxylic acid containing molecular oxygen gas in the presence of at least one catalyst effective upon receipt of alkenylacyl, obtaining this alkenylboronic.

The allocation method of the present invention is described below on the example of alkane oxidation with2With4obtaining product stream comprising the corresponding alkene, alkane and oxygen, and the joint processes for its implementation.

In response Oka the population in the preferred embodiment, alkane with 2With4represents ethane, and the corresponding alkene is ethylene, and the corresponding carboxylic acid is acetic acid. These products can be fed into the reaction in the subsequent processes of obtaining ethyl acetate or containing molecular oxygen gas with the receipt of vinyl acetate.

The oxidation reaction is typically conducted in a heterogeneous environment using solid catalysts and reagents in the liquid phase. In this case, the concentration of the optional alkene and optionally water in the oxidation reaction zone can be adjusted partial pressures.

Catalysts effective for the oxidation of the alkane to alkene and carboxylic acid may include any acceptable catalysts known in the art, such as those used for the oxidation of ethane to ethylene and acetic acid, are described in the following patents and applications: US 4596787, EP-A 0407091, DE 19620542, WO 99/20592, DE 19630832, WO 98/47850, WO 99/51339, EP-A 1043064, WO 99/13980, US 5300682 and US 5300684, the contents of which are incorporated into this description by reference.

Patent US 4596787 relates to a method of low-temperature oxidative dehydrogenation of ethane to ethylene using a catalyst, corresponding to the empirical formula MoaVbNbcSbdXeas it is presented in the mentioned patent, moreover, these elements are combined with oxygen.

EP-A 0407091 relates to a method and catalyst for producing ethylene and/or acetic acid by the oxidation of ethane and/or ethylene in the presence of an oxidation catalyst comprising molybdenum, rhenium and tungsten.

DE 19620542 relates to oxidation catalysts based on molybdenum, palladium and rhenium for obtaining acetic acid from ethane and/or ethylene.

WO 99/20592 relates to a method for selective receipt of acetic acid from ethane, ethylene or mixtures thereof and oxygen at high temperature in the presence of a catalyst corresponding to the formula MoaPdbXcYdin which X represents one or more of the following elements: Cr, Mn, Nb, TA, Ti, V, Te and W; Y represents one or more of the following elements: B, Al, Ga, In, Pt, Zn, Cd, Bi, Ce, Co, Rh, Ir, Cu, Ag, Au, Fe, Ru, Os, K, Rb, Cs, Mg, Ca, Sr, Ba, Nb, Zr, Hf, Ni, P, Pb, Sb, Si, Sn, Tl, and U, and represents 1, b represents a number from 0.0001 to 0.01, with denotes a number from 0.4 to 1, and d denotes a number from 0,005 to 1.

DE-A1 19630832 belongs to the similar catalytic composition, and which denotes 1, b>0, C>0, d denotes a number from 0 to 2. In the preferred embodiment, and represents 1, b represents a number from 0.0001 to 0.5, with denotes a number from 0.1 to 1.0, and d denotes a number from 0 to 1.0.

WO 98/47850 relates to a method for producing acetic acid from ethane, ethylene or mixtures thereof in the presence of a catalyst corresponding to the formula WaXbYcZd

WO 99/51339 relates to catalytic compositions for the selective oxidation of ethane and/or ethylene to acetic acid; the composition comprises in combination with oxygen the elements MoaWbAgcIrdXeYfwhere X denotes the elements Nb and V; Y represents one or more elements selected from the group including Cr, Mn, TA, Ti, In, Al, Ga, In, Pt, Zn, Cd, Bi, CE, Co, Rh, Cu, Au, Fe, Ru, Os, K, Rb, Cs, Mg, Ca, Sr, Ba, Zr, Hf, Ni, P, Pb, Sb, Si, Sn, Tl, U, Re and Pd; and a , b, C, d, e, and f denotes the gram-atom ratios of the elements, in which 0<a≤1; 0≤b<1 and a+b=1; 0<(c+d)≤0,1; 0<e≤2 and 0≤f≤2.

EP-A 1043064 relates to catalytic compositions for the oxidation of ethane to ethylene and/or acetic acid and/or for the oxidation of ethylene to acetic acid; the composition comprises in combination with oxygen the elements molybdenum, vanadium, niobium and gold in the absence of palladium according to the empirical formula MoaWbAucVdNbeYfin which Y represents one or more elements, you the early group, including Cr, Mn, TA, Ti, In, Al, Ga, In, Pt, Zn, Cd, Bi, Ce, Co, Rh, Ir, Cu, Ag, Fe, Ru, Os, K, Rb, Cs, Mg, Ca, Sr, Ba, Zr, Hf, Ni, P, Pb, Sb, Si, Sn, Tl, U, Re, Te and La; a, b, c, d, e, and f denotes the gram-atomic ratio elements, in which 0<and≤1; 0≤b<1 and a+b=1; 10-5<with≤0,02; 0<d≤2; 0<e≤1 and 0≤f≤2.

WO 99/13980 relates to a catalyst for selective oxidation of ethane to acetic acid corresponding to the formula MoaVbNbcXdin which X denotes at least one promoter element selected from the group comprising P, B, Hf, Te and As; and denotes a number in the range from about 1 to about 5; b is 1; C represents a number in the range from about 0.01 to about 0.5, and d denotes a number in the range from greater than 0 to about 0.1.

US 5300682 relates to the application of oxidation catalyst of the empirical formula VPaMbOxwhere M denotes one or more elements of a number of Co, Cu, Re, Fe, Ni, Nb, Cr, W, U, TA, Ti, Zr, Hf, Mn, Pt, Pd, Sn, Sb, Bi, Ce, As, Ag and Au, and denotes a number from 0.5 to 3, b is 0,1, and x corresponds to the valence requirements.

US 5300684 refers to the oxidation reaction in the fluidized bed using, for example, Mo0,37Reof 0.25V0,26Nb0,07Sb0,03Ca0,02Ox.

Other acceptable for use in the present invention, the oxidation catalysts presented in the application WO 99/13980, which belongs to p is the physical alteration of catalysts with elements, in combination with oxygen in the relative gram-atom ratios of MoaVbNbcXdwhere X denotes P, B, Hf, Te, or As; US patent 6030920, which refers to the use of catalysts with elements in combination with oxygen in the relative gram-atom ratios of MoaVbNbcPdd; application WO 00/00284, which refers to the use of catalysts with elements in combination with oxygen in the relative gram-atom ratios of MoaVbNbcPddand/or MoaVbLacPdd; patent US 6087297, which refers to the use of catalysts with elements in combination with oxygen in the relative gram-atom ratios of MoaVbPdcLad; application WO 00/09260, which refers to the use of catalysts with elements in combination with oxygen in the relative gram-atom ratios of MoaVbLacPddNbeXfwhere X denotes a Cu or Cr, and each of e and f may denote zero; applications WO 00/29106 and WO 00/29105 that relate to the use of catalysts with elements in combination with oxygen in the relative gram-atom ratios of MoaVbGacPddNbeXfwhere X denotes the La, Te, Ge, Zn, Si, In or W; and WO 00/38833, which refers to the use of catalysts with elements in combination with oxygen in the relative gram-atom ratios of MoaVbLacPddNbeXfwhere X represents Al, Ga, Ge or Si, the content of which is incorporated into this description by reference.

Solid catalysts are effective in the oxidation of alkane with2With4can be carriers and not printed on the media. Examples of acceptable carriers include silica, diatomaceous earth, montmorillonite, aluminum oxide, silicon dioxide/aluminum oxide, zirconium dioxide, titanium dioxide, silicon carbide, activated carbon and mixtures thereof.

Solid catalysts are effective in the oxidation of alkane C2C4can be used in the form of a fixed or fluidized bed.

Assume that the oxidation catalyst provides, apparently, the oxidation of at least part of any alkene sent to the oxidation reaction zone, for example, to the corresponding carboxylic acid.

Containing molecular oxygen gas used in the oxidation reaction zone, may be air or a gas richer or poorer in molecular oxygen than air. Acceptable gas can represent, for example, oxygen diluted with sootvetstvuyuschayatrebovaniyam, for example nitrogen or carbon dioxide. Preferred containing molecular oxygen gas is oxygen. Containing molecular oxygen gas can be directed into the oxidation reaction zone in the form of a single stream of source materials, including alonovoa raw materials. This thread alkane/containing molecular oxygen gas can be obtained from the allocation process from a mixture of alkene alkene/alkane/gaseous molecular oxygen.

In a preferred embodiment, at least some part containing molecular oxygen gas is directed to the oxidation reaction zone, regardless of the filing alkangovolo and optional alkinoos raw materials and recycle all materials.

It is advisable containing molecular oxygen gas (in the form of fresh feedstock and/or recycle component) is such that the oxygen concentration is from greater than 0 up to and including 20 mol.% of the total amount of source material, including recycle components directed in the oxidation reaction zone, preferably from 2 to 15 mol.%.

Alkane and alkene sent to the oxidation reaction zone may be substantially pure or may be mixed, for example, with one or more materials such as nitrogen, argon, methane, carbon dioxide, monoxide of plastics technology : turning & the Yes, hydrogen and small amounts of alkenes/alkanes with C2With4.

Suitable concentration of alkene (in the form of fresh feedstock and/or recycle component) is from 0 up to and including 50 mol.% of the total amount of material, including recycle components directed in the oxidation reaction zone, preferably from 1 to 20 mol.%, more preferably from 1 to 15 mol.%.

It is advisable to water (in the form of fresh feedstock and/or recycle component) is from 0 to 50 mol.% inclusive of the total amount of material, including recycle components directed in the oxidation reaction zone, preferably from 0 to 25 mol.%.

In one embodiment, the present invention alkene, such as ethylene, and water is introduced into the oxidation reaction zone together.

Accordingly, alkene, such as ethylene, and water can be used in a mass ratio of 1:0.1 to 250, in particular 1:0.1 to 100 or 1:0.1 to 50, but preferably in a mass ratio of 1:0.1 to 10.

When in the oxidation reaction zone use solid catalysts, alkane corresponding alkene containing molecular oxygen gas, an optional water recycle gases in the preferred embodiment, is passed through the oxidation reaction zone with length of stay in it, the corresponding total CPE is necasova rate of gas supply (SPG) from 500 to 10000 h -1and SSPG defined as the amount of [calculated at standard temperature and pressure (CTD)] of the gas passing through the reactor, divided by the bulk volume of the precipitated catalyst.

The oxidation reaction can be effectively carried out at a temperature in the range from 100 to 400°typically in the range from 140 to 350°C.

The oxidation reaction can be effectively carried out under atmospheric or elevated pressure, for example under a gauge pressure in the range from 5 to 27 bar.

During the oxidation reaction of the present invention typically can be achieved in the conversion of alkane in the interval from 1 to 99%.

During the oxidation reaction of the present invention typically can be achieved in the conversion of oxygen in the range from 30 to 99.99%.

The oxygen concentration in the product stream is usually to some extent depends on the degree of conversion of alkane and the degree of selectivity in the products. A high degree of conversion of alkane usually leads to a low concentration of oxygen contained in the product stream. High selectivity for the resulting alkene usually leads to a high concentration of oxygen in the product stream.

The maximum (safe) concentration of oxygen in the product stream is determined by the range Flammability ratio m is waiting for oxygen and alkanol after separation from it alkene.

Thus, although the concentration of oxygen contained in the product stream from the oxidation reaction zone may be below 0.1 mol.%, she usually is at least 0,1 mol.%, in particular at least 0.2 mol.%. Provided that the ow is non-flammable, suitable oxygen concentration in the product stream is in the range from 0.1 up to and including 10 mol.%, in particular from 0.2 to 8 mol.%, for example, from 0.2 to 6 mol.%.

Acceptable performance of the catalyst during the oxidation reaction is in the range from 10 to 10,000 g of carboxylic acid, such as acetic acid, per hour per kilogram of catalyst.

Acceptable performance of the catalyst during the oxidation reaction is in the range from 5 to 5000 g alkene, such as ethylene per hour per kilogram of catalyst.

Carbon monoxide may have a negative impact on some of the catalysts used in the preparation of vinyl acetate. Thus, depending on the nature of the catalyst it is necessary that the first product stream contains carbon monoxide as a by-product in low concentration.

Thus, in the preferred embodiment, in the oxidation reaction zone using a catalyst, which causes the formation of minor amounts of MES is carbon monoxide as a by-product. For oxidation of carbon monoxide to carbon dioxide in the oxidation reaction zone may be used for additional catalytic component. This additional catalytic component may be present in the catalyst or catalysts of oxidation or the second reaction zone, or may be contained in the oxidation reaction zone as a separate catalyst.

When the oxidation process as a reagent use ethane, the product stream comprises acetic acid, ethylene, unreacted ethane, oxygen and water and may also contain inert gaseous components, such as argon and nitrogen, as well as by-products, acetic aldehyde, carbon monoxide and carbon dioxide. Acetaldehyde and carbon monoxide may be turning containing molecular oxygen gas with the formation of, respectively, acetic acid and carbon dioxide or in a subsequent process line processes, or after return to the process in the oxidation reaction zone.

The ethylene contained in the stream of reaction products of oxidation as unreacted ethylene reagent from the source material and/or as a product of oxidation of ethane reactant.

The product stream withdrawn from the oxidation reaction zone, in the first separation among the as separated into a gaseous stream, comprising alkene, unreacted alkane and oxygen, and a liquid stream comprising carboxylic acid. You can apply any acceptable separation means known in the art, such as a membrane separating unit, condenser installation or distillation system. In the preferred embodiment, as a separating agent is applied to the condenser.

When the product stream from the oxidation reaction include acetic acid, ethylene, ethane, oxygen and water, this product stream can be separated, and that preferably separated by condensation on the head of a gaseous stream comprising ethylene, ethane and oxygen, and the bottom liquid stream comprising acetic acid and water. Normally gaseous stream also includes oxides of carbon, such as carbon dioxide.

From the stream of products of the oxidation reaction can be selected optionally, carboxylic acid and/or alkene.

The gaseous stream from the first separation means is introduced into contact with a solution of a metal salt capable of selectively chemically absorbing alkene, to form a liquid stream rich in chemically absorbed by the alkene.

Acceptable metal salts are those with alkene capable of forming a complex.

When the alkene is ethylene, acceptable metal salts in luchot chrome, copper (I), manganese, Nickel, iron, mercury, silver, gold, platinum, palladium, rhodium, ruthenium, osmium, molybdenum, tungsten and rhenium.

The preferred metal salt comprises silver or copper (I), most preferably silver.

When the metal salt is a salt of silver, the preferred silver salt is silver nitrate or perborate silver.

When the metal salt is a salt of copper (I), the preferred salt of copper (I) is the acetate of copper (I)nitrate copper (I) or copper sulphate (I), most preferably the nitrate of copper (I).

The metal salt solution may be water or may include nitrogen-containing organic compound, such as pyridine, piperidine, hydroxypropionitrile, Diethylenetriamine, acetonitrile, formamide, ndimethylacetamide and their derivatives.

The preferred metal salt solution is an aqueous solution.

When the metal salt is a salt of copper (I)acceptable concentration of metal salt relative to the nitrogen-containing compounds is in the range from 1:1 to 1:6, preferably is 1:2.

Suitable concentration of metal salt in the solution is at least a 0.5 mole of metal salt per liter of solvent, preferably at least 2 mol of metal salt per liter of solvent.

Neither alkane or oxygen contained in a gaseous stream, skolik is any significant extent the complex with a solution of metal salt form.

Contacting the gaseous stream with a solution of metal salt can be accomplished in any acceptable means, in particular in the absorption column. This absorption column can be equipped with plates or packing, such as rings process or structured packings. The preferred absorption column equipped with a nozzle.

To increase the purity of the alkene absorption column, it is advisable to equip the boiler.

In a preferred variant of the process in the absorption column is carried out with a flow after the flow of gas and a solution of metal salt.

Suitable contacting can be performed at a temperature in the range from -10 to 300°C, preferably from 0 to 100°C.

Suitable contacting can be performed under a gauge pressure in the range from 1 to 70 bar, preferably from 3 to 30 bar.

When the contacting is carried out in an absorption column, a solution of a metal salt comprising a complex metal salt/alkene can be removed from the base of the absorber.

As alkane and oxygen complex with the metal salt solution to any significant extent not form, they are taken from the absorption column in the form of the head of the stream.

Trace amounts of oxygen and/or alkane, absorbed by a solution of metal salt, remove from the solution mainly about the time alkene.

Rich alkene stream may be selected from a metal salt solution by heating under reduced pressure or a combination thereof. In a preferred embodiment, the solution is affected by reduced pressure, the resulting complex is decomposed with the release of the alkene.

The pressure to extract rich in alkene stream from a solution of metal salt, may be from 2 to 98% of the absolute pressure generated to obtain a complex metal salt/alkene, preferably from 10 to 80% of the absolute pressure generated to obtain the complex.

Another variant-rich alkene stream may be separated from the salt solution of the metal degassing at temperatures that range from 0 to 80°C, preferably in the range from 15 to 35°C higher than the temperature of formation of the complex.

Rich alkene stream can also be isolated from solution using a combination of reduced pressure and elevated temperature.

The decompression can be performed in one or several stages, for example in one or more settings for flash evaporation.

When using one or more settings for flash evaporation, rich alkene stream away from them in the form of the head of the stream. This kind of thread before optional drying can be compressed. Another option g is lowney stream before compression can be dried. When rich alkene stream is compressed, it can be compressed to a pressure suitable for feed to the second reaction zone. In an expedient embodiment, it can be compressed to the pressure of any additional alkene fed to the second reaction zone.

Free alkene complex can be returned to the process for reuse in the absorber.

Rich alkene stream typically includes alkene and may include low concentrations of alkane and oxygen and other impurities, such as carbon dioxide.

In an expedient variant-rich alkene stream, such as rich in ethylene stream comprises at least 50% of the alkene, in particular at least 80% of the alkene. In a preferred variant-rich alkene stream comprises at least 90% of the alkene, more preferably 95% alkene, and most preferably at least 99% of the alkene.

Rich alkene stream may be selected from a metal salt solution in one or several stages of absorption/desorption, in particular one-stage absorption and two-stage desorption.

In a suitable embodiment, the use of feed alkene in the second reaction zone containing impurities in low concentrations, can reduce the amount of purge gas to be discharged into the atmosphere from the second reaction zone, and hence also reduce the loss of the alkene from the second reaction zone.

Stream alkane and oxygen (rich alkanol stream can contain low concentrations of alkene and other impurities, such as carbon dioxide. This rich alkanes thread must be non-flammable. Range Flammability usually depends on temperature and pressure rich alkanol flow, however, the concentration of oxygen in rich alkanol thread, as a rule, can be in the range from 0.1 to 10 mol.%.

When implementing the method according to the present invention prior to contact with the salt solution of the metal to remove components such as carbon dioxide and oxygen-containing substances such as acetaldehyde, in the preferred embodiment, the gaseous stream alkene/alkane/oxygen (gaseous stream from the first separation means) process.

The gaseous stream containing alkane and oxygen, in the form of one or more streams can be directed to the oxidation reaction zone together with additional alkanol.

Before serving in the oxidation reaction zone a stream containing alkane and oxygen, can, optionally, be divided into separate gaseous streams alkane and oxygen.

Additional alkanol may serve fresh alkane and/or they can serve as unreacted alkane from the oxidation reaction zone, after which the first section is sustained fashion funds are returned to the oxidation reaction zone.

Stream alkane/oxygen and additional alkane you can enter into the oxidation reaction zone either as separate streams of source materials, either in the form of a single stream of source materials, including alkane/oxygen and additional alkane.

Rich alkene stream is sent in the form of one or more flows into the second reaction zone together with additional containing molecular oxygen gas, an optional additional alkene and carboxylic acid, to obtain alkenylacyl, such as vinyl acetate.

Rich alkene stream and additional alkene can be injected into the second reaction zone either as separate streams of source materials, either in the form of a single stream of source materials, including rich alkene stream and additional alkene.

Additional alkene may serve fresh alkene and/or returned to the process from the second reaction zone alkene and/or a part of the flow alkane/alkene from the oxidation reaction zone.

Additional alkene introduced into the second reaction zone to obtain alkenylboronic may be essentially pure or may be mixed, for example with one or more components, such as nitrogen, argon, methane, carbon dioxide, carbon monoxide, hydrogen and low concentrations of other alkenes/and the Cana with 2C4.

Suitable concentration of alkene (optional Allenby source material and rich alkene stream source material), such as ethylene, directed to the second reaction zone is at least 50 mol.% of the total amount of material introduced into the second reaction zone, preferably at least 55 mol.%, more preferably at least 60 mol.%. It is advisable to alkene of up to 85 mol.% of the total amount of material introduced into the second reaction zone, preferably in the range from at least 50 to 80 mol.%, in particular at least 55 to 80 mol.%.

In the method according to the present invention can be applied is known in the art catalysts receiving alkenylbenzenes. So, for example, catalysts, effective upon receipt of vinyl acetate, which upon implementation of the present invention can be used in the second reaction zone may include, in particular, the catalysts are presented in GB 1559540, US 5185308 and EP-A 0672453, the contents of which are incorporated into this description by reference.

In GB 1559540 described catalyst, effective upon receipt of vinyl acetate by reaction of ethylene, acetic acid and oxygen, and the catalyst essentially comprises (1) a catalyst carrier, the diameter of h is STIC which is from 3 to 7 mm, and the specific pore volume is equal to from 0.2 to 1.5 ml/g, and the pH value of the suspension of this catalyst carrier in water concentration of 10 wt.% is from 3.0 to 9.0, (2) paradiishotel alloy distributed in a surface layer of a catalyst carrier, and this surface layer is at a distance of less than 0.5 mm above the surface of the carrier, palladium in the alloy is contained in an amount of from 1.5 to 5.0 g/l of catalyst, and the gold is contained in an amount of from 0.5 to 2.25 g/l of catalyst, and (3) from 5 to 60 g of the alkali metal acetate per liter of catalyst.

In the US 5185308 described catalyst impregnated with sheath, effective upon receipt of vinyl acetate from ethylene, acetic acid and oxygen-containing gas, and the catalyst essentially comprises (1) a catalyst carrier particle diameter which is from about 3 to about 7 mm, and the specific pore volume is equal to from 0.2 to 1.5 ml/g, (2) palladium, and gold, distributed in the layer thickness of 1.0 mm particles of the catalyst carrier, and (3) from about 3.5 to about 9.5 wt.% potassium acetate, where the value of the mass ratio between gold and palladium in the catalyst is in the range of from 0.6 to 1.25.

In EP-A 0672453 described palladium catalysts for the conduct of processes of production of vinyl acetate in the fluidized bed and cooking.

The process of obtaining and what canalcaracol, such as vinyl acetate, in the second reaction zone, as a rule, is carried out in heterogeneous conditions, and the reactants are in the gas phase.

Containing molecular oxygen gas used in the second reaction zone to obtain alkenylacyl, may include a gas containing unreacted molecular oxygen, from the stage (a) and/or additional containing molecular oxygen gas.

Additional containing molecular oxygen gas, if used, may be air or a gas richer or poorer in molecular oxygen than air. Acceptable additional containing molecular oxygen gas may represent, for example, oxygen diluted with a suitable diluent, such as nitrogen, argon or carbon dioxide. Preferred additional containing molecular oxygen gas is oxygen. In a preferred embodiment, at least some part containing molecular oxygen gas is directed to the second reaction zone, regardless of the submission as reagents alkene and carboxylic acid.

Carboxylic acid supplied to the second reaction zone to obtain alkenylboronic may include fresh and/or returned to the process acid. In a preferred embodiment, at least an hour is carboxylic acid, introduced into the second reaction zone includes a carboxylic acid derived from the oxidation reaction zone.

Fresh and return in the process carboxylic acid can be injected into the second reaction zone either as separate streams of source materials, either in the form of a single stream of source materials, including both fresh and returned to the process acid.

Carboxylic acid supplied to the second reaction zone to obtain alkenylboronic may include at least part of the acid obtained in the subsequent processes, in particular in the process of separating acid from a mixture of this acid/alkenylboronic/water.

At least part of the carboxylic acid, which is directed to the second reaction zone may be liquid.

When the second reaction zone to obtain alkenylboronic use of solid catalysts, alkene from the second separation means, carboxylic acid withdrawn from the oxidation reaction zone, the entire additional alkene or carboxylic acid as reagents, all recycle streams containing molecular oxygen gas in the preferred embodiment, is passed through a second reaction zone at a compound average rate of gas supply (SPG) from 500 to 10000 h-1.

The process of obtaining alkenylboronic the second re is klonoa area can be effectively carried out at a temperature in the range from 140 to 200° C.

The process of obtaining alkenylboronic in the second reaction zone can be effectively carried out under a gauge pressure in the range from 50 to 300 pounds per square inch.

The process of obtaining alkenylboronic in the second reaction zone can be effectively conducted either in a fixed or fluidized bed.

Upon receipt of alkenylboronic in the second reaction zone can be achieved, the degree of conversion of carboxylic acids in the range of from 5 to 80%.

Upon receipt of alkenylboronic in the second reaction zone can be achieved, the degree of conversion of the oxygen in the range from 20 to 100%.

Upon receipt of alkenylboronic in the second reaction zone can be achieved, the degree of conversion of the alkene in the range of from 3 to 100%.

Acceptable performance of the catalyst upon receipt of alkenylboronic in the second reaction zone is in the range from 10 to 10000 g alkenylboronic/h·kg of catalyst.

When the method according to the present invention as alkane use ethane, the product stream withdrawn from the second reaction zone to obtain alkenylacyl, may include vinyl acetate, water and acetic acid, and optionally unreacted ethylene, ethane, oxygen, acetic aldehyde, nitrogen, argon, carbon monoxide and dioxide angle of the ode. This product stream can be divided azeotropic distillation at the top fraction comprising vinyl acetate and water, and the bottom fraction comprising acetic acid and water. The bottom fraction away from the base of the distillation column as a liquid bottoms. In addition, one or more steps above the base of the column, you can also take steam. Before this stage distillation from the second product stream can be removed ethylene, ethane, acetaldehyde, carbon monoxide and carbon dioxide if they are reasonable in view of the upper gaseous fraction scrubbing column, from the base of which divert the liquid fraction comprising vinyl acetate, water and acetic acid. Ethylene and/or ethane can be returned to the oxidation reaction zone and/or the second reaction zone, and/or the second separation means.

From the top fraction was isolated by alkenylacyl, in particular vinyl acetate, which is useful, for example, by decantation. If necessary, a dedicated alkenylacyl, such as vinyl acetate, can be subjected to additional purification by a known method.

The bottom fraction comprising carboxylic acid, such as acetic acid, and water, further purified, preferably without treatment, you can return to the second reaction zone. Another option from the bottom fracc and allocate carboxylic acid, which if necessary can be subjected to additional purification by a known method, for example by distillation.

The invention is further illustrated with reference to the drawing.

In this drawing, in the form of a block diagram of the plant that is acceptable for use in the method according to the present invention.

This installation includes the oxidation reaction zone (1), provided with a means (3) supply of ethane and optionally ethylene, a means (4) feed containing molecular oxygen gas, means (5) feed recycle gas comprising ethane and ethylene, means (19) supply of ethane and oxygen from the column (21) for absorption of ethylene/ethane/oxygen, and discharge means (18) for the first product stream. Depending on the scale, the method of oxidation reaction zone (1) may include either a single reactor or multiple reactors, placed in parallel or sequentially.

The installation also includes a scrubber (6) for the selection of the first product stream in the form of a gaseous stream comprising ethylene, ethane and carbon dioxide, and a liquid stream comprising acetic acid and water. This setting does not necessarily includes a means (not shown) for removal of acetic acid water, such as distillation system.

The installation also includes a number of devices (22, 23) for mcneven the nd evaporation (valves and drums for flash evaporation) for effects on complex ethylene/metal salt, obtained in the form of the bottom fraction from the absorption column (21), low blood pressure and an optional compressor (24) for compression-rich ethylene downstream flow device (22, 23) for flash evaporation.

The installation also includes a second reaction zone (2) for acetoxysilane of ethylene to vinyl acetate, which is provided with means (17) for transporting at least part of the acetic acid from the scrubber (6) in the second reaction zone, optionally with means for removing water from a liquid stream, means (9) feed containing molecular oxygen gas, means (10) feed recycle acetic acid, an optional tool or means (8) submission of acetic acid and/or ethylene and means (25) filing of ethylene optional compressor (24). Depending on the scope of the method the second reaction zone (2) may include either a single reactor or multiple reactors, placed in parallel or sequentially.

The installation further includes a scrubber (12) for the product from the second reaction zone, means (13) for separation of acetic acid from the product of the second reaction zone, means (14) cleaning of vinyl acetate, an optional feature of (15) purification of acetic acid and one or more separation means (16) for separation of carbon dioxide from gotoblas the wow thread derived from the scrubber (6), and optionally to retrieve the ethylene product.

During operation the oxidation reaction zone (1) provide at least one catalyst effective for the oxidation of ethane with obtaining acetic acid and ethylene. As oxidation catalysts, it is advisable to use solid catalysts. Containing molecular oxygen gas is fed into the oxidation reaction zone (1) from (4) flow through one or more inlet holes. Gaseous starting material comprising ethane and ethylene, send in the oxidation reaction zone (1) from (3) filing. In the oxidation reaction zone (1) from (5) submission enter recycle gas comprising ethane and ethylene. From (19) filing in the oxidation reaction zone (1) direct the ethane and oxygen is withdrawn from the absorption column (21).

Containing molecular oxygen gas, ethane, ethylene and recycle gas is fed into the oxidation reaction zone (1) via one or more inlet holes separately or in partial or complete combination. At least one of the flows into the oxidation reactor, optionally includes water.

In the oxidation reactor to receive the first stream of products which includes ethylene (as a product and/or unreacted is a similar material), acetic acid, water, optional unspent containing molecular oxygen gas, unreacted ethane and by-products such as carbon monoxide, carbon dioxide, inert components and acetic aldehyde. At least a portion of the product stream is sent to the scrubber (6), which assign a gaseous stream comprising ethylene, ethane, oxygen and carbon dioxide and a liquid stream comprising acetic acid and water. At least part of this gaseous stream after separation of by-products such as carbon dioxide, in the separation means (16) and an optional selection of the ethylene product by methods in the art known guide in the absorption column (21) high pressure. At least part of the gaseous stream comprising ethylene and ethane, from the separation means (16) by using the feeder (5) return in the oxidation reaction zone (1). A gaseous stream comprising ethylene, ethane and oxygen, is directed to an absorption column (21), which contains the silver nitrate solution, interacts with the ethylene with the formation of a complex of silver nitrate/ethylene. Ethane and oxygen complex does not form, they should be removed from this column in the form of the head of the stream. From the base of the absorption column to remove the solution provided is a complex of silver nitrate/ethylene. This solution is passed through a series of evaporative drum (22, 23), where he is under the influence of low pressure. In such conditions, the complex of silver nitrate/ethylene decomposes with release of ethylene. Ethylene is isolated in the form of the head of the stream. Before serving, using (25) feed to the second reaction zone (2) head-stream of ethylene is sent to the compressor (24). Using (19) feeding a stream of ethane/oxygen from the absorption column is sent to the oxidation reaction zone (1).

Acetic acid may be selected from liquid flow scrubber (6), for example, by distillation.

At least a portion of the acetic acid from the liquid stream by means of (17) is directed, not necessarily through the means of removal of water (not shown), the second reaction zone (2), which provided the catalyst for acetoxysilane, suitable solid catalyst. Containing molecular oxygen gas from the means (9) direct feed to the second reaction zone. Acetic acid is directed to the second reaction zone of the tool (10) feed recycle stream. Additional ethylene and/or acetic acid can, optionally, be sent to the second reaction zone of the vehicle or vehicles (8) filing. Ethylene is supplied from the separation means (21) to the second reaction zone with means (22) filing. Vinegar is th acid from a liquid scrubbing stream, containing molecular oxygen gas, recycle acetic acid, optional additional input quantities of ethylene and/or acetic acid and ethylene from the separation means (21) is directed to the second reaction zone through one or more inlet devices separately or in partial or complete combination.

In the second reaction zone ethylene, acetic acid and molecular oxygen to interact with the formation of the second product stream comprising vinyl acetate.

The second reaction product is fed into the scrubber (12), from which emit gas and liquid. In one or more stages of separation (not shown) by methods in the art known from this gas into carbon dioxide and optional Recuperat ethylene product. The remaining ethylene and ethane can be returned in the first and/or second reaction zone. Of the scrubbing liquid in the separation means (13) include acetic acid, and using (10) filing a return in the second reaction zone. Acetic acid as a product, you may (optionally) be allocated from the recycle stream by using (15), for example, by distillation. Acetate product is recovered from the scrubber liquid using (14), for example, by distillation.

1. The method of alkane oxidation with2C4half is for the corresponding alkene and carboxylic acid, includes the following stages:

(a) contacting in an oxidation reaction zone alkane containing molecular oxygen gas, not necessarily corresponding alkene and optionally water, in the presence of at least one catalyst effective for the oxidation of the alkane to the corresponding alkene and carboxylic acid, to obtain a first product stream comprising alkene, carboxylic acid, alkane, oxygen and water;

(b) separating in a first separation means at least part of the first product stream in a gaseous stream comprising alkene, alkane and oxygen, and a liquid stream comprising carboxylic acid;

(C) contacting mentioned gaseous stream with a solution of a metal salt capable of selectively chemically absorbing alkene, to form a liquid stream rich in chemically absorbed by alkene;

(g) isolation of the salt solution of the metal-rich alkene stream.

2. United way of obtaining alkylcarboxylic, comprising the following stages:

(a) contacting in an oxidation reaction zone alkane containing molecular oxygen gas, not necessarily corresponding alkene and optionally water, in the presence of at least one catalyst effective for the oxidation of the alkane to the corresponding Elke the a and carboxylic acid, with receipt of the first non-flammable product stream comprising alkene, carboxylic acid, alkane, oxygen and water;

(b) separating in a first separation means at least part of the first product stream in a gaseous stream comprising alkene, alkane and oxygen, and a liquid stream comprising carboxylic acid;

(C) contacting at least part of the aforementioned gaseous stream with a solution of a metal salt capable of selectively chemically absorbing alkene, to form a liquid stream rich in chemically absorbed by alkene;

(g) isolation of the salt solution of the metal-rich alkene stream; and

(e) contacting the second reaction zone at least part of this rich alkene stream from step (g) and carboxylic acid in the presence of at least one catalyst effective upon receipt of alkylcarboxylic, with obtaining the specified alkylcarboxylic.

3. United way of obtaining alkenylacyl, comprising the following stages:

(a) contacting in an oxidation reaction zone alkane containing molecular oxygen gas, not necessarily corresponding alkene and optionally water, in the presence of at least one catalyst effective for the oxidation of the alkane to the corresponding alkene and arbonboy acid, with receipt of the first non-flammable product stream comprising alkene, carboxylic acid, alkane, oxygen and water;

(b) separating in a first separation means at least part of the first product stream in a gaseous stream comprising alkene, alkane and oxygen, and a liquid stream comprising carboxylic acid;

(C) contacting at least part of the aforementioned gaseous stream with a solution of a metal salt capable of selectively chemically absorbing alkene, to form a liquid stream rich in chemically absorbed by alkene;

(g) isolation of the salt solution of the metal-rich alkene stream; and

(e) contacting the second reaction zone at least part of this rich alkene stream obtained in stage (d), carboxylic acid containing molecular oxygen gas in the presence of at least one catalyst effective upon receipt of alkenylacyl, obtaining this alkenylboronic.

4. The method according to claim 3, in which in stage (d) mentioned rich alkene stream sent to the second reaction zone in the form of one or more threads together with optional additional alkene.

5. The method according to claim 4, in which additional alkene may serve fresh alkene and/or recycle alkene from the second reactions is authorized zone, and/or part of the flow alkane/alkene from the oxidation reaction zone stage (a).

6. The method according to one of p-5, in which the concentration of alkene (optional Allenby source material and rich alkene stream source material)supplied to the second reaction zone is at least 50 mol.% of the total amount of material introduced into the second reaction zone.

7. The method according to claim 6, in which the concentration of the alkene is at least 60 mol.% of the total amount of material introduced into the second reaction zone.

8. The method according to claim 6, in which the concentration of the alkene of up to 85 mol.% of the total amount of material introduced into the second reaction zone.

9. The method according to claim 3, which contains molecular oxygen gas used in the second reaction zone to obtain alkenylboronic includes unreacted containing molecular oxygen gas from stage (a) and/or additional containing molecular oxygen gas.

10. The method according to claim 9, in which additional contains molecular oxygen gas is oxygen.

11. The method according to claim 3, in which at least a number containing molecular oxygen gas is directed to the second reaction zone, regardless of the submission as reagents alkene and carboxylic acid.

12. With whom persons according to claim 3, in which carboxylic acid is introduced into the second reaction zone includes a carboxylic acid derived from the oxidation reaction zone.

13. The method according to one of claims 1 to 3, in which the alkane is chosen from the group comprising alkanes with C2With4and mixtures thereof.

14. The method according to one of claims 1 to 3, in which the alkane is a ethane, corresponding alkene represents ethylene, and the corresponding carboxylic acid is an acetic acid.

15. The method according to one of claims 1 to 3, which contains molecular oxygen gas in stage (a) represents the oxygen.

16. The method according to one of claims 1 to 3, in which the concentration containing molecular oxygen gas (in the form of fresh feedstock and/or recycle component) is from above 0 to 20 mol.% from the total amount introduced into the oxidation reaction zone of the material, including recycle components.

17. The method according to one of claims 1 to 3, in which the concentration of alkene (in the form of fresh feedstock and/or recycle component) is from 0 to 50 mol.% from the total amount introduced into the oxidation reaction zone of the material, including recycle components.

18. The method according to 17, in which the concentration of the alkene is 1 to 20 mol.% of the total amount of material introduced into the oxidation reaction zone.

19. The method according to one of claims 1 to 3, in which to the centering of water (in the form of fresh feedstock and/or recycle component) is from 0 to 50 mol.% from the total amount introduced into the oxidation reaction zone material, including recycle components.

20. The method according to claim 19, in which the water concentration is from 0 to 25 mol.% of the total amount of material introduced into the oxidation reaction zone.

21. The method according to one of claims 1 to 3, in which the alkene and water is fed into the oxidation reaction zone together.

22. The method according to one of claims 1 to 3, in which the alkene and water use in a mass ratio of 1:0.1 to 250.

23. The method according to one of claims 1 to 3, in which the concentration of oxygen contained in the gaseous stream from the first separation means is at least 0,1 mol.%.

24. The method according to item 23, in which the concentration of oxygen contained in the gaseous stream from the first separation means is at least 0.2 mol.%.

25. The method according to item 23, in which the concentration of oxygen contained in the gaseous stream from the first separation means, ranges from 0.1 to 10 mol.%.

26. The method according to one of claims 1 to 3, in which the first separation means is a membrane separating installation condenser installation or distillation unit.

27. The method according to p where applicable separation means is a capacitor.

28. The method according to one of claims 1 to 3, in which the alkene is an ethylene, and a metal salt capable of selectively chemically absorbing alce is, includes chrome, copper (I), manganese, Nickel, iron, mercury, silver, gold, platinum, palladium, rhodium, ruthenium, osmium, molybdenum, tungsten or rhenium.

29. The method according to p in which metal salt comprises silver or copper (I).

30. The method according to clause 29, in which the metal salt is a salt of silver.

31. The method according to item 30, in which the silver salt is a silver nitrate or perborate silver.

32. The method according to clause 29, in which the metal salt is an acetate of copper (I)nitrate copper (I) or copper sulphate (I).

33. The method according to one of claims 1 to 3, in which the solution of the metal is an aqueous or organic nitrogen-containing compound.

34. The method according to one of claims 1 to 3, in which the contacting of the gaseous stream from the first separation means with a solution of metal salt is carried out in an absorption column.

35. The method according to clause 34, in which the metal salt solution comprising a complex metal salt/alkene, remove from the base of the absorption column, and the alkane and oxygen are removed from the absorption column in the form of the head of the stream.

36. The method according to p, in which a gaseous stream containing alkane and oxygen, is directed to the oxidation reaction zone in the form of one or more flows, together with the additional alkanol.

37. The method according to p, in which prior to being fed into the oxidation reaction zone, the flow, the content is of ASI alkane and oxygen, divided into separate gaseous streams alkane and oxygen.

38. The method according to p or 37, in which the secondary alkane is a fresh alkane and/or unreacted alkane from the oxidation reaction zone, which returned to the oxidation reaction zone after the first separation means.

39. The method according to p, in which the flow alkane/oxygen and additional alkane is introduced into the oxidation reaction zone together or as separate streams of source materials, either in the form of a single stream of source materials, including alkane/oxygen and additional alkane.

40. The method according to one of claims 1 to 3, in which rich alkene stream is recovered from the solution of the complex metal salt by heating under reduced pressure or a combination thereof.

41. The method according to p, in which the solution is affected by reduced pressure, the resulting complex is decomposed with the release of the alkene.

42. The method according to one of claims 1 to 3, in which rich alkene stream comprises at least 50% of the alkene.

43. The method according to 42, which is rich in alkene stream comprises at least 90% of the alkene.

44. The method according to one of claims 1 to 3, in which the gaseous stream from the first separation means prior to contacting with the metal salt solution is treated to remove components selected from the group include the it carbon dioxide and oxygen-containing substances.

45. United way of getting vinyl acetate, comprising the following stages:

(a) contacting in an oxidation reaction zone ethane containing molecular oxygen gas, an optional ethylene and optionally water, in the presence of at least one catalyst effective for the oxidation of ethane to ethylene and acetic acid, to obtain the first non-flammable product stream comprising ethylene, acetic acid, ethane, oxygen and water;

(b) separating in a first separation means at least part of the first product stream in a gaseous stream comprising ethylene, ethane and oxygen, and a liquid stream comprising acetic acid;

(C) contacting at least part of the aforementioned gaseous stream with a solution of a metal salt capable of selectively chemically absorbing the ethylene, to form a liquid stream rich in chemically absorbed ethylene;

(g) isolation of the salt solution of the metal-rich ethylene stream; and

(e) contacting the second reaction zone at least part of the above rich in ethylene stream obtained in stage (g), acetic acid and containing molecular oxygen gas in the presence of at least one catalyst effective upon receipt of vinyl acetate, obtaining VI is racette.

46. The method according to claim 7, in which the concentration of the alkene of up to 85 mol.% of the total amount of material introduced into the second reaction zone.



 

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