RU2458903C1 - Method of producing cyclohexanone and cyclohexanol and apparatus for realising said method - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: present invention relates to a method of producing cyclohexanone and cyclohexanol, as well as an apparatus for realising said method. The disclosed method involves processing a reaction liquid containing cyclohexane, cyclohexanone, cyclohexanol, cyclohexyl hydroperoxide and organic acids from a cyclohexane oxidation step, and involving cooling the reaction liquid, neutralisation thereof with an alkali, separation into a first aqueous-alkaline layer and a first organic layer, decomposition of the cyclohexyl hydroperoxide in the presence of a catalyst and an alkali, and separation of a second aqueous-alkaline layer, return thereof into the cyclohexyl hydroperoxide decomposition unit and for neutralisation, and separation of a second organic layer for distillation of cyclohexane with extraction of cyclohexanone and cyclohexanol and returning cyclohexane to its oxidation step. After cooling, the reaction liquid is washed from organic acids by feeding water into its stream followed by separation of the aqueous-acidic layer and cleaning thereof via extraction with cyclohexane and returning the extract into the stream of the reaction liquid, and distillation of the raffinate with separation of the aqueous-acidic runoff and distillate which is fed into the stream of the reaction liquid, and the prepared organic layer is fed to the neutralisation step in form of a mixture of the washed reaction liquid and extract containing cyclohexyl hydroperoxide.

EFFECT: invention enables to obtain the end products using a simple and cheap method.

8 cl, 1 ex, 2 dwg

Description

The inventions relate to the technology for producing cyclohexanone and cyclohexanol and its hardware implementation by high-temperature non-catalytic oxidation of cyclohexane with atmospheric oxygen in order to obtain cyclohexane oxidation products containing cyclohexanone, cyclohexanol and cyclohexyl hydroperoxide followed by catalytic decomposition of the latter. The final product cyclohexanone used to produce ε-caprolactam is isolated from oxidation products by known methods.

Polyamide-6 or polycaprolactam is one of the main thermoplastic materials for producing threads, fibers, as well as various cast products [based on the book Production of caprolactam. Ed. V.I. Ovchinnikov and V.R.Ruchinsky. M .: Chemistry, 1977. - 263 p.]. This polymer is obtained by polymerization of ε-caprolactam. This compound can be obtained in various ways, in particular the preparation of cyclohexanone oxime from cyclohexanone. The latter must have a high degree of purity, in order to avoid the introduction of impurities, which could also impair the properties of the obtained polyamide, in particular its color, resistance to aging.

Cyclohexanone is usually prepared by oxidizing cyclohexane in a liquid state with an oxygen-containing gas to obtain a cyclohexanone / cyclohexanol mixture, and then, after purification and separation of cyclohexanol from cyclohexanone, by dehydrogenation of cyclohexanol to cyclohexanone.

The oxidation of cyclohexane to obtain a cyclohexanone / cyclohexanol mixture is carried out either in a single stage, in the presence of an oxidation catalyst, or in the first stage by oxidizing cyclohexane to cyclohexyl hydroperoxide without a catalyst, purification of the reaction mixture by washing with water, and then catalytic decomposition of this hydroperoxide into cyclohexanone and cyclohexanol.

During these oxidation stages, numerous impurities are formed, such as aldehydes, acids, alcohols and ketones. These impurities are separated from the mixture of cyclohexanone / cyclohexanol and removed from the process.

In the case of oxidation of cyclohexane to cyclohexyl hydroperoxide, treatment with the basic compound (metal hydroxide) is also used with its subsequent recovery in the form of waste that is disposed of, for example, by burning.

A known method for producing cyclohexanone from cyclohexane, which includes the steps of oxidizing cyclohexane to cyclohexyl hydroperoxide with oxygen in the absence of a catalyst, purifying the reaction medium by washing with water, decomposing cyclohexyl hydroperoxide into cyclohexanol and cyclohexanone in the presence of a catalyst, extracting a cyclohexanol / cyclohexanone mixture with separation of nepropane higher boiling point than the mixture of cyclohexanol / cyclohexanone, dehydrogenation of cyclohex sanol contained in the mixture of cyclohexanol / cyclohexanone in the presence of a dehydrogenation catalyst, distillation of this mixture to obtain a compound with a boiling point below the boiling point of cyclohexanone and ultimately obtaining cyclohexanone having an increased degree of purity suitable for use as a raw material for the synthesis of ε-caprolactam [Description of the invention to the patent of the Russian Federation No. 2373181 of November 30, 2005, IPC C07C 49/403, C07C 45/53, C07C 45/39, publ. November 20, 2009]. The method allows to obtain cyclohexanone that meets the purity criteria required to obtain ε-caprolactam, in particular UV test.

The disadvantages of the method include the complexity and multi-stage process with its separation into specific phases, each of which has individual requirements for the presence-absence of catalysts, which are used as oxides of copper, magnesium, zinc and their mixtures, process temperature and neutralization conditions.

A known method of decomposition of cyclohexyl hydroperoxide with a high yield of cyclohexanol and cyclohexanone, comprising the following stages: washing with water the final products of the cyclohexane oxidation process, phase separation and processing of the organic phase with an aqueous alkaline solution, where the volume ratio of the aqueous phase / organic phase is from about 0.10: 100 to 1.00: 100. Next, the next phase separation and mixing of the organic phase with the catalyst are carried out, after which the aqueous alkaline phase containing the catalyst is removed, and the resulting organic phase is washed with water. It is possible to reuse part of the aqueous alkaline phase by returning it to the stage of processing the first organic layer and recycling the separated aqueous phase to the first stage of washing the starting product for decomposition. The alkaline solution can be prepared on the basis of alkaline hydroxides or alkaline carbonates with an alkaline solution concentration of from 2 to 25 wt.% With the addition of a cobalt catalyst in the range of 5 to 15 ppm [Description of the invention to RF patent No. 2308445 of 03.06.2003, IPC С07С 45/53, С07С 35/08, С07С 409/06, publ. 10/20/2007). As a result, the cyclohexyl hydroperoxide is almost completely converted to cyclohexanol and cyclohexanone.

Cyclohexyl hydroperoxide is one of the components of a complex organic mixture of a reaction liquid designed to extract cyclohexanone and cyclohexanol. This technology has the same drawbacks as the well-known technologies for the decomposition of cyclohexyl hydroperoxide - the need to use catalysts, their subsequent separation from the reaction mixture and return to the technological cycle, as well as the need for multi-stage (in several phases) treatment of the organic layer with base solutions. In addition, there is no stage of the isolation of cyclohexanone and cyclohexanol from the aqueous phase and their return to the process.

A known method of producing products of the oxidation of cyclohexane by catalytic liquid-phase oxidation with oxygen-containing gases at elevated temperatures, the liquid cyclohexane and oxygen-containing gases being passed countercurrently through the reaction zone, which is divided into several interconnected chambers using perforated plates. Oxygen-containing gas is introduced along the reaction zone through nozzle openings uniformly distributed over the cross section of the reaction zone, as a result of which a continuous gas phase is not created in the reaction zone. The gas inlet distances are 0.1-3 times the diameter of the reaction zone. Moreover, the gas is introduced into the reaction zone, where oxygen from the previous input is not completely consumed. The temperature in the reactor is 120-180 ° C, the pressure is 5-30 bar (Description of the invention to the patent of the Russian Federation No. 2181116 from 10.17.1997, IPC 7, C07C 27/12, C07C 35/08, C07C 49/403, publ. 10.04. 2002]. Technical result - the formation of by-products, for example, caproic acid, which is removed from the reaction mixture by washing with water and sodium liquor to obtain wastewater with a high salt content and a high content of organic compounds, is reduced, and the reactor productivity is increased.

The disadvantage of this method is the necessity of washing with water and sodium hydroxide the entire reaction mass, which leads to a significant consumption of alkali.

The closest to the essential features of the claimed technical solution is a method for producing cyclohexanone and cyclohexanol, including the neutralization of acids and / or carbon dioxide present in an organic solution, which, in addition, contains cyclohexyl hydroperoxide by mixing the organic solution with the first aqueous base solution to form the first mixture comprising the first aqueous phase and the first organic phase, partial separation of the aqueous phase from the first mixture, resulting in a cm b) comprising the first organic phase, decomposing the cyclohexyl hydroperoxide contained in the remaining mixture by mixing this remaining mixture with a second aqueous base solution to form a second mixture comprising a second aqueous phase and a second organic phase containing cyclohexanone and cyclohexanol, and separating the second aqueous phase from second organic phase. Additionally, part of the separated second aqueous phase from the second organic phase is fed to the neutralization step and part of the separated second aqueous phase is fed to the decomposition step. As a result, the remaining mixture is distilled, including the second organic phase to obtain cyclohexanone and cyclohexanol [Description of the invention to patent EA No. 011023 from 12.30.2008, IPC С07С 35/08, С07С 49/403, С07С 29/132, С07С 45/53, publ. CDROM / Bulletin [eab] EAB 20806]. The process provides increased selectivity for cyclohexanone and cyclohexanol and improved separation obtained after decomposition of the mixture.

The disadvantages of the method include the complex scheme of processing the oxidizing and reaction mixtures with base solutions and the need to use a catalyst — a water-soluble salt of a transition metal, for example cobalt sulfate, as well as increased alkali consumption due to the processing of the entire reaction mass with an aqueous alkaline solution.

The problem solved by the first invention of the group, and the technical result achieved, are to eliminate the listed disadvantages, simplify the process, improve the quality of separation of the organic and aqueous acid layers and remove the aqueous acid drain before the neutralization stage, which will save alkali and process water and reduce amount of water-alkaline runoff for disposal.

To solve the problem and achieve the claimed technical result in a method for producing cyclohexanone and cyclohexanol, which consists in processing a reaction liquid containing cyclohexane, cyclohexanone, cyclohexanol, cyclohexyl hydroperoxide, organic acids and esters coming from the stage of cyclohexane oxidation, and including its cooling, neutralization with alkali separation into a first aqueous alkaline layer and a first organic layer; decomposition of cyclohexyl hydroperoxide in the presence of a catalyst and / or lye and separation of the second water-alkaline layer, its return to the decomposition unit of cyclohexyl hydroperoxide and neutralization and separation of the second organic layer for distillation of cyclohexane with return of cyclohexane to the stage of its oxidation and distillation of the mixture of cyclohexane oxidation products separated from cyclohexane with the release of cyclohexane and cyclohexanol, after cooling, the liquid is washed from organic acids by feeding (injection) of water into its stream, followed by separation of the aqueous-acidic layer and its purification by extraction with cyclohexane with the return of the extract into the stream of the reaction liquid, and distillation of the raffinate with the release of a water-acid stream and distillate, which is fed into the stream of the reaction liquid, and the prepared organic layer is fed to the neutralization stage as a mixture of the washed reaction liquid and the extract containing hydroperoxide cyclohexyl.

Additionally, the washing of the aqueous acidic layer is carried out in the presence of fresh or reverse cyclohexane at a temperature of not more than 70 ° C and the content of cyclohexanone and cyclohexanol in the reverse cyclohexane in the amount of not more than 0.8 wt.%, And the distillate after distillation of the raffinate is mixed with water for washing acids from the reaction liquid.

There are various options for the hardware design of methods for producing cyclohexanone and cyclohexanol, in particular, the known method according to patent EA No. 011023 of 12/30/2008 in general can be implemented on a plant including a reaction liquid supply unit, a reaction liquid cooling unit, and a reactor neutralization of oxidation products, a separation vessel of the first organic and first water-alkaline layer, a decomposition unit of cyclohexyl hydroperoxide and equipped with a separator the output of the second organic layer with the separation unit of the second water-alkaline layer associated with the decomposition unit of the hydroperoxide and the neutralization reactor.

The problem solved by the second invention of the group and the technical result achieved are to simplify the design of the technological process for producing cyclohexanone and cyclohexanol, to improve the quality of separation of the organic and aqueous acid layers and to remove the aqueous acid stream before the neutralization stage, which will save alkali and process water and reduce the amount of water-alkaline runoff for disposal.

To solve the problem and achieve the claimed technical result in the installation for producing cyclohexanone and cyclohexanol, which includes a technological fluid supply unit with cyclohexane oxidation reactors, a reaction fluid cooling unit, an oxidation product neutralization reactor, a separation vessel of the first organic and first aqueous alkaline layers, a decomposition unit of cyclohexyl hydroperoxide and a separation unit of a second water-alkaline separation unit equipped with a separator layer associated with the decomposition unit of the hydroperoxide and the neutralization reactor and equipped with the output of the second organic layer associated with the distillation unit for the separation of cyclohexane, cyclohexanone and cyclohexanol, between the cooling unit of the reaction liquid and the neutralization reactor there is a washing unit made in the form of a mixer of the reaction liquid and water and the separation vessel of the organic and aqueous acidic layers, which is connected with the extractor of the aqueous acidic layer and, further, with a raffinate purification device, wherein the acid-water layer tractor and the raffinate purification device are additionally connected to the unit for washing the reaction liquid with water, and the raffinate-purification device is provided with an acid-water drainage unit.

Besides:

- the raffinate purification device is connected to the unit for washing the reaction liquid with water through the unit for its supply;

- the separation vessel of the organic and aqueous acidic layers is made in the form of a separator or sump;

- the extractor of the water-acid layer is made of a pulsation or rotor-disk, or packed;

- the raffinate purification device is made in the form of a packed or plate distillation column.

The invention is illustrated by drawings, where:

- figure 1 shows a functional diagram of a method for producing cyclohexanone and cyclohexanol;

- figure 2 is a diagram of the installation for implementing the method for producing cyclohexanone and cyclohexanol with a unit for washing from organic acids.

The method of producing cyclohexanone and cyclohexanol can be implemented on the appropriate installation, which in the most general form includes located in the technological sequence unit 1 for supplying the reaction liquid (a), consisting mainly of cyclohexane (the so-called reaction unit - oxidation unit), unit 2 cooling of the reaction liquid, reactor 3 for neutralizing oxidation products, separation vessel 4 of the first organic (b) and first water-alkaline (c) layers, decomposition unit 5 of cyclohexyl hydroperoxide and equipped with a separator with a torus, a unit 6 for separating the second aqueous alkaline layer (d), connected to a unit 5 for decomposition of hydroperoxide and a neutralization reactor 3, and equipped with a terminal 7 for a second organic layer (e), connected to a unit for its distillation (not shown conventionally) for the isolation of cyclohexane, cyclohexanone and cyclohexanol.

Between the cooling unit 2 of the reaction liquid (a) and the neutralization reactor 3, a washing unit 8 is arranged in the form of a mixer of the cooled reaction liquid (a ') and water and a separation vessel 9 of the organic (f) and aqueous acidic (g) layers, which is connected with the extractor 10 of the aqueous acidic layer (g) and, further, with the device 11 for cleaning the raffinate (h), while the extractor 10 of the aqueous acidic layer (g) and the device 11 for cleaning the raffinate (h) are additionally connected to the washing unit 8 of the cooled reaction liquid (a ') with water, and the raffinate purification device 11 (h) is provided about the node (not shown conventionally) drainage of water-acidic runoff (k) and is connected with the node 8 washing the cooled reaction liquid (a ') with water through the node 12 of its supply.

Structurally, the separation vessel 9 of the organic (f) and aqueous acidic (g) layers can be made in the form of a separator or settling tank, the extractor 10 of the aqueous acidic layer (g) (at the first stage of purification of the aqueous acidic drain (k) is made pulsating, rotary -disc or packed, and the raffinate purification device 11 (h) (for the final cleaning of the acid-water effluent (k)) is made in the form of a packed or plate distillation column.

The method for producing cyclohexanone and cyclohexanol consists in processing the flow of the reaction liquid (a) containing cyclohexane, cyclohexanone, cyclohexanol, cyclohexyl hydroperoxide, organic acids and esters coming from the stage of cyclohexane oxidation - from the unit 1 for supplying the reaction liquid (a), and includes cooling it in node 2, neutralization with alkali in reactor 3, separation in vessel 4 into a first aqueous alkaline layer (b) and a first organic (c) layer, decomposition of cyclohexyl hydroperoxide in the presence of a catalyst and / or alkali in node 5 and the separation of the second water-alkaline layer (d) in node 6, its return (d ') to the node 5 decomposition of cyclohexyl hydroperoxide (d' ') and neutralization in the reactor 3 and the separation of the second organic layer (e) for distillation of cyclohexane with the return of cyclohexane (reverse cyclohexane) to the stage of its oxidation and distillation of a mixture of cyclohexane oxidation products separated from cyclohexane with the release of cyclohexanone and cyclohexanol.

The difference between the method is that the stream of the reaction liquid (a) after cooling (a ') is washed from organic acids by feeding (injection) of water into its stream, which occurs in the washing unit 8, followed by separation of the aqueous acid layer (g ) and its purification by extraction with cyclohexane with the return of the extract stream (I) from the extractor 10 to the cooled stream of the reaction liquid (a ') and distillation of the raffinate (h) with the release of aqueous acidic effluent (k) and distillate (m), which cooled stream of reaction liquid (a '), and to the stage of neutral lysing serves prepared organic layer (f) in the form of a mixture of washed reaction liquid (a '') and extract (I) containing cyclohexyl hydroperoxide. In addition, the washing of the aqueous acidic layer (g) is carried out in the presence of fresh or reverse cyclohexane at a temperature of not more than 70 ° C and the content of cyclohexanone and cyclohexanol in reverse cyclohexane in the amount of not more than 0.8 wt.%, And the distillate (m) after distillation of the raffinate (h) is mixed with water supplied to the washing (extraction) of the acids from the cooled reaction liquid (a ').

Let us analyze the essential features of inventions.

Unlike the known methods for producing cyclohexanone and cyclohexanol, the present method provides for washing the reaction liquid from organic acids included in its composition, for example, adipic, caproic, oxycaproic and others, before applying to the stage of neutralization. Washing is carried out by supplying to the stream (a ') a cooled reaction liquid of water. In its simplest form, this can be organized as an injection of one to three parts of water per 100 parts of the reaction liquid into unit 8 — a specially equipped slit and / or diaphragm type mixer, the structural elements of which (diameter, length, etc.) should be sufficient obtaining a given level of flow turbulence (a``), which provides satisfactory mixing. Water is taken from the supply unit 12, where it comes from the device 11 - raffinate purification columns (distillate (m)) with the addition of the required amount of pure water or water from other technological stages, suitable for return to the technological process. As a result of mixing the reaction liquid with water, a significant part of the most polar oxidation products, namely acids, passes into the aqueous phase. In addition to acids, less polar compounds — cyclohexanone, cyclohexanol, and cyclohexyl hydroperoxide — partially pass into the aqueous phase. In the separation vessel 9, the aqueous-acidic layer (g), which has a higher density compared to the organic layer (f), is collected at the bottom of the container and removed for washing with fresh or reverse cyclohexane to the extractor 10. In the extractor 10, mainly cyclohexanone, cyclohexanol are transferred to cyclohexane and cyclohexyl hydroperoxide, and the organic acids remain in the raffinate (h). Dissolved organic products cyclohexane (extract (I)) is returned to the cooled stream (a ') of the reaction liquid.

The extraction of cyclohexanone and cyclohexanol from the aqueous acidic layer (g) is carried out in the presence of fresh or reverse cyclohexane at a temperature of not more than 70 ° C, although a temperature range of 50 ° C to 60 ° C is preferred, in which the mass transfer between the phases remains high, and the equilibrium concentrations of oxidation products in water and cyclohexane are relatively optimal. The content of cyclohexanone and cyclohexanol in reverse cyclohexane in the amount should not exceed 0.8 wt.%. At a higher concentration, the degree of extraction of these products from the aqueous layer (a``) is significantly reduced.

The raffinate (h) for final purification from the extractor 10 is fed into the corresponding device 11 — a packed or plate distillation column with the release of an aqueous-acidic effluent (k), sent for disposal, in particular for a thermal decomposition unit (not shown conditionally), and distillate ( m) returned to the stream (a ') of the reaction liquid together with water going to the washing of the acids contained therein.

Due to the washing off of the acids, the prepared organic layer (f) is supplied to the neutralization stage in the form of a mixture of the washed reaction liquid (a``) and the extract (I). Washing does not ensure the complete release of acids from the reaction liquid (a``), however, their content becomes much lower, which also requires significantly less alkali to neutralize it.

In particular, the study of known methods for the oxidation of cyclohexane showed that the alkali consumption is:

- during catalytic oxidation without washing off acids - 150 kg per ton of cyclohexanone;

- in case of non-catalytic oxidation without neutralization of acids - 120 kg per ton of cyclohexanone;

- in non-catalytic oxidation with neutralization of acids - 100 kg per ton of cyclohexanone;

- during catalytic oxidation with washing of acids - 90 kg per ton of cyclohexanone.

In the inventive method for non-catalytic oxidation of cyclohexane with washing the reaction liquid and neutralizing acids - about 55 kg per ton of cyclohexanone.

Otherwise, the method for producing cyclohexanone and cyclohexanol provides for the same steps and the same typical equipment for their implementation as in the known methods that are part of the technology for the production of caprolactam.

As a result of applying the method, the specific yield of water-alkaline runoff (first water-alkaline layer (s)) is reduced by 30-50% compared with methods that do not include acid washing, which provides a proportional reduction in emissions of harmful substances, such as soda, when thermal decomposition of alkaline runoff.

The hardware of the method for producing cyclohexanone and cyclohexanol can be represented by a variety of equipment, however, for its most effective operation, the following can be recommended:

- for the separation of organic (f) and aqueous-acidic (g) layers - a separation vessel 4 in the form of a gravity settler, hollow or with internal devices that facilitate the coalescence of droplets of the aqueous phase;

- for the extraction of the aqueous acidic layer (in the first stage of purification of the aqueous acidic runoff) - pulsating or rotary disk, or nozzle extractor 10;

- for the final purification of aqueous-acidic (g) runoff, the raffinate purification device 11 (h) is a packed or plate distillation column.

A method for producing cyclohexanone and cyclohexanol will be considered using the operation of the corresponding installation as an example.

Part of the fresh and recycled cyclohexane enter the reaction unit 1, which is a scrubber 13 and a cascade of reactors 14 of its oxidation. At the outlet of the reactors 14, we have a reaction liquid (a) with a temperature of 160-170 ° C, which enters the cooling unit 2 — a heat exchanger (recuperator) 15 and a refrigerator 16, where its temperature is reduced to 50 due to the transfer of heat to the cyclohexane and cooling water -60 ° C. The cooled reaction liquid (a ') enters the mixer — the washing unit 8, where it is mixed with water coming from the supply unit 12, and they are intensively mixed and the acids are dissolved in the dispersed aqueous phase. The mixture (a``) of the reaction liquid and water with the acids dissolved in it enters the separation vessel 9 of the organic (f) and aqueous-acidic (g) layers, which is a typical settler. The organic layer consisting mainly of cyclohexane (f), as having a lower density compared to aqueous acid solutions, flows from the upper zone of the sump into the neutralization reactor 3. The aqueous-acidic layer (g) that accumulates in the lower part of the separation vessel 9, which contains organic acids, impurities of cyclohexanone, cyclohexanol and hydroperoxides, enters, for example, a pulsation extractor 10. An extractant, fresh or reverse cyclohexane, is extracted there, which extracts dissolved in water-acid layer dissolved cyclohexanone and cyclohexanol. Extract (I), containing cyclohexanone, cyclohexanol and cyclohexyl hydroperoxide dissolved in cyclohexane, is collected in buffer tank 17 and sent to stream (a ') (or even stream (a')) of the reaction liquid. Cyclohexane is a product that is constantly circulating in the process. As a result of the oxidation of cyclohexane in one pass, 3-5% of the initial amount is consumed, and the system is replenished due to the constant supply of fresh cyclohexane to the extraction stage of the aqueous acid layer (g) in the extractor 10, and the remaining necessary amount of cyclohexane is added to the cyclohexane.

The aqueous acidic layer - raffinate (h) - from the extractor 10 is sent for purification to a distillation column 18, where distillate (m) is extracted from it by evaporation in the evaporator 19, which enters the buffer tank 20 of the water supply unit 12 for washing the acids after passing the condenser 21 and the acid-water effluent (k) exiting the bottoms 22 is transferred for disposal, for example, for incineration.

The organic layer (f) of the reaction liquid received in the neutralization reactor 3 after washing off the acids is treated with alkali, for example, an aqueous solution of caustic soda, which requires a significantly lower amount compared to similar plants where the initial stream (a``) of the reaction liquid is neutralized. the reactor 3 to neutralize the oxidation products, the mixture is fed into a separation vessel 4 of the first organic (b) and the first water-alkaline (c) layers. The separation occurs due to a significant difference in the densities of the organic (b) and water-alkaline (c) phases. The aqueous alkaline layer (c) is removed by distillation of the cyclohexanone and cyclohexanol contained therein. The first organic layer (b) containing cyclohexanone, cyclohexanol, cyclohexyl hydroperoxide and impurities of other oxidation products enters the hydroperoxide decomposition unit 5, where in a cascade of several reactors 23 with stirrers at a temperature of about 90 ° C in the presence of aqueous alkali and a catalyst, selective decomposition of hydroperoxide cyclohexyl into cyclohexanone and cyclohexanol.

The mixture from decomposition unit 5 is fed to unit 6 of the separation of the second aqueous alkaline layer (d), which is an aqueous solution of alkali and salts of organic acids. The main part (d ') of the separated second water-alkaline layer (d), comprising approximately 85-90%, is again returned to the decomposition unit 5 to create the necessary ratio of aqueous and organic phases, and the rest (d' ') containing excess alkalinity enters the neutralization reactor 3 together with the organic layer (f) after washing the acids to neutralize the acid residues.

As a result of decomposition of cyclohexane hydroperoxide and separation of the second aqueous alkaline layer (d), a second organic layer (e) is obtained, which is used for distillation of cyclohexane, where, according to traditional technology, cyclohexanone and cyclohexanol are separated, which go to the stage of their separation and purification.

As a result of the use of the inventions, the separation quality of the organic and aqueous-acidic layers has improved, and the possibility of discharging the aqueous-acidic effluent before the neutralization stage has appeared, thereby saving alkali and substantially halving the amount of aqueous-alkaline effluent for disposal.

Claims (8)

1. The method of producing cyclohexanone and cyclohexanol, which consists in processing the reaction liquid containing cyclohexane, cyclohexanone, cyclohexanol, cyclohexyl hydroperoxide and organic acids coming from the stage of cyclohexane oxidation, and including cooling the reaction liquid, neutralizing it with alkali, separation into the first aqueous alkaline layer and the first organic layer, the decomposition of cyclohexyl hydroperoxide in the presence of a catalyst and alkali, and the separation of the second water-alkaline layer, its return to the decomposition unit hydrolysis of cyclohexyl and neutralization, and the separation of the second organic layer for distillation of cyclohexane with the release of cyclohexanone and cyclohexanol and the return of cyclohexane to the stage of its oxidation, characterized in that the reaction liquid is washed from organic acids after cooling by supplying water to its stream, followed by separation water-acid layer and its purification by extraction with cyclohexane with the return of the extract into the stream of the reaction liquid, and distillation of the raffinate with the release of water-acid eye and a distillate which is fed to the reaction liquid stream and fed to the neutralization step organic layer was prepared as a mixture of the washed reaction liquid and extract containing cyclohexyl hydroperoxide. 2. The method according to claim 1, characterized in that the washing (extraction of cyclohexanone and cyclohexanol) of the aqueous acidic layer is carried out in the presence of fresh or reverse cyclohexane at a temperature of not more than 70 ° C and the content of cyclohexanone and cyclohexanol in reverse cyclohexane in the amount of not more than 0 , 8 wt.%. 3. The method according to claim 1, characterized in that the distillate after distillation of the raffinate is mixed with water supplied to the washing of acids from the reaction liquid. 4. Installation for producing cyclohexanone and cyclohexanol, including a technological fluid supply unit with cyclohexane oxidation reactors, a reaction fluid cooling unit, an oxidation product neutralization reactor, a separation vessel of the first organic and first aqueous alkaline layer, a cyclohexyl hydroperoxide decomposition unit and equipped the separator node separation of the second water-alkaline layer associated with the decomposition unit of the hydroperoxide and the neutralization reactor, and equipped with a conclusion of the second organic layer associated with its distillation unit for the isolation of cyclohexane, cyclohexanone and cyclohexanol, characterized in that a washing unit is installed between the cooling unit of the reaction liquid and the neutralization reactor, made in the form of a mixer of the cooled reaction liquid and water and a separation vessel of organic and water -acid layers, which is associated with the extractor of the aqueous acidic layer and, further, with the purification device of the raffinate, while the extractor of the aqueous-acidic layer and the purification device raffinate is further connected to a node of washing the reaction liquid with water and raffinate purification device provided with a drain node aqueous acidic effluent. 5. Installation according to claim 4, characterized in that the raffinate purification device is connected to a washing unit for washing the reaction liquid with water through its supply unit. 6. Installation according to claim 4, characterized in that the separation vessel of the organic and aqueous acidic layers is made in the form of a separator or sump. 7. Installation according to claim 4, characterized in that the aqueous-acidic layer extractor is made pulsating, or rotary-disk, or packed. 8. The installation according to claim 4, characterized in that the raffinate purification device is made in the form of a packed or plate distillation column.

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