The method of oxidation of hydrocarbons, alcohols and/or ketones

 

(57) Abstract:

The invention relates to an improved method for the oxidation of cyclic hydrocarbons, alcohols and/or ketones to carboxylic acids with oxygen or oxygen-containing gas. The method is carried out in liquid phase in a solvent, which is selected from a proton polar solvents and aprotic polar solvents and in the presence of a catalyst soluble in the reaction mixture, and the catalyst contains one soluble compound of manganese and/or cobalt, one soluble chromium compound and one soluble compound of iron, and the amount of catalyst in the reaction mixture is 0.0001-5 wt.%, mainly, of 0.001-2 wt.% with respect to the reaction mixture. The method using a catalyst having high activity, can increase the selectivity and efficiency of the oxidation process. 15 C.p. f-crystals.

The invention relates to the oxidation of hydrocarbons to carboxylic acids, alcohols and/or ketones, and alcohols and/or ketones to the corresponding carboxylic acids with oxygen or oxygen-containing gas.

The method of direct oxidation of hydrocarbons, in particular, cycloalkanones advantages and eliminates the use of such oxidizing agent, as nitric acid, which is currently used in one of the phases of industrial methods of oxidation, and to avoid, therefore, necessary, disposal of the resulting oxides of nitrogen.

In numerous embodiments of this method of catalytic oxidation with oxygen is the most commonly used catalyst is cobalt.

In particular, in U.S. patent 2223493, published in December 1940, describes a method of oxidation of cyclic hydrocarbons in the corresponding dibasic acid, which is carried out in the liquid phase, usually containing acetic acid, at a temperature of at least 60C using a gas containing oxygen, in the presence of an oxidation catalyst such as a compound of cobalt.

Further, in U.S. patent 4902827, published in February 1990, describes an improved method of oxidation with air of cyclohexane to adipic acid, which is carried out in the liquid phase containing acetic acid, at a temperature of from 80 to 160S in the presence of an oxidation catalyst containing a soluble compound of cobalt and soluble compound of zirconium and/or hafnium.

In a recently published European patent A-0694333 pre what about the salt, cobalt salt of trivalent iron.

To improve selectivity in the European patent 0870751 claimed the use of a catalyst containing a salt of cobalt and chromium salt.

As another example of a commonly used catalyst in this reaction the oxidation can lead manganese.

To reduce costs and simplify purification of the products obtained, it is preferable to use the minimum concentration of catalyst. In this regard, the manganese is an important catalyst in the ways of the oxidation of cyclohexane.

However, if the selectivity of the catalytic systems described in the above methods is acceptable, the performance of these methods should be improved so that it was possible to use this reaction in the industry.

This is the task of the present invention. It is, in particular, relates to a method for oxidation of hydrocarbon, alcohol and/or ketone with oxygen or oxygen-containing gas, which is carried out in the liquid phase in the presence of a catalyst soluble in the reaction medium, characterized in that the catalyst contains at least one soluble compound of manganese and/or cobalt, at least one soluble is lesuuda as starting compounds in the method according to the invention, are, in particular, alkanes, cycloalkanes, alkylaromatic hydrocarbons, alkenes and cycloalkenes containing from 3 to 20 carbon atoms.

Among these hydrocarbons, the most important are cycloalkanes, in particular cycloalkanes having a cycle comprising from 5 to 12 carbon atoms, as the process of their oxidation leads to the production of dicarboxylic acids and intermediate education cycloalkanones and cycloalkanones.

The most important hydrocarbon is cyclohexane, the oxidation process which leads to the production of adipic acid, which is one of the main components in the synthesis of polyamide 6-6, and may also lead to the production of cyclohexanone from which synthesize caprolactam and then the polyamide 6.

The method according to the present invention can also be used for oxidation of the intermediate alcohols or ketones, in particular cycloalkanones or cycloalkanones having from 5 to 12 carbon atoms, to obtain the corresponding dicarboxylic acids. In this regard, the method according to the invention describes, in particular, oxidation of hydrocarbons, mainly cycloalkanes, and even more preferably the oxidation of cyclohexane.

The catalytic system is Yu and high yield of adipic acid by direct oxidation of cyclohexane. The properties of a specified catalyst are obvious advantages to using the oxidation reaction in the industry.

The catalytic system contains either at least one compound of manganese, soluble in the reaction mixture, which selects, for example, not limiting the present invention, manganese chloride, manganese bromide, manganese nitrate and manganese carboxylates, such as the tetrahydrate of manganese acetate, manganese propionate, adipate manganese, glutarate manganese, manganese succinate, or at least one compound of cobalt, dissolved in the reaction mixture, which selects, for example, not limiting the present invention of cobalt chloride, cobalt bromide, cobalt nitrate and cobalt carboxylates, such as acetate tetrahydrate cobalt propionate, cobalt, adipate cobalt, glutarate cobalt, cobalt succinate.

The catalyst also contains at least one chromium compound soluble in the reaction mixture, which selects, for example, not limiting the present invention of chromium chloride, chromium bromide, chromium nitrate and chromium carboxylates, such as chromium acetate, chromium propionate, adipate chromium, glutarate chroma least one connection, iron, soluble in the reaction mixture, which selects, for example, not limiting the present invention halides of iron, iron nitrate, iron carboxylates, such as acetate, propionate, succinate, glutarate, adipate, iron chelates, such as acetylacetonates of iron.

Finally, the catalyst may also contain at least one compound of zirconium and/or hafnium, soluble in the reaction mixture, which selects, for example, not limiting the present invention zirconium chloride, zirconium bromide, zirconium nitrate and zirconium carboxylates, such as zirconium acetate, zirconium propionate, adipate zirconium, glutarate zirconium, succinate, zirconium, and hafnium chloride, hafnium bromide, nitrate hafnium and hafnium carboxylates, such as hafnium acetate, propionate, hafnium, adipate hafnium, glutarate hafnium, succinate hafnium.

The molar ratio between the manganese and/or cobalt, chromium and iron in the catalytic system can vary widely. It is possible, therefore, to use a molar ratio of mn and/or Co/Cr/Fe, mainly in the range of from 1/0,00001/0,0001 to 1/100/100, more predominantly in the range of from 1/0,001/0,01 to 1/10/10.

The quantity qi is the I to the manganese or cobalt, similar to the previously specified for chrome.

The catalyst may be obtained at the time of mixing compounds of manganese and/or cobalt, chromium, iron, and, if necessary, zirconium or hafnium in the reaction mixture. It can also be obtained immediately before use by mixing the above compounds in the proportions necessary to obtain the molar ratio of manganese to Co/Cr/Fe and, if necessary, Zr and/or Hf. This mixture preferably receive, using a solvent, preferably a solvent of the same chemical nature as that which is used for oxidation reaction, or get the catalyst directly in the solvent for the reaction of oxidation.

The amount of catalyst, expressed in weight percent metals (manganese, cobalt, chromium, iron, and, if necessary, zirconium or hafnium) in relation to the reaction mixture, usually from 0.0001 to 5%, mainly from 0.001 to 2%, so these values were not critical. However, it should be sufficient, but not excessive, to ensure the necessary activity of the catalyst. In fact, the catalyst after the implementation of the response to the use of the initiator of oxidation. The initiators are often hydroperoxides, such as a hydroperoxide of the cyclohexyl or tert-butyl hydroperoxide. They can also be ketones or aldehydes, for example cyclohexanone, which is one of the compounds formed during the oxidation of cyclohexane or of acetaldehyde. In General, the initiator is contained in an amount of from 0.01 wt.% up to 20 wt.% from the mass used in the reaction mixture, so that these values are not critical. The initiator is often used to initiate oxidation reactions and in the case when conducting the oxidation of cyclohexane at a temperature of less than 120C. The initiator can be introduced to the first reaction stage.

The liquid reaction mixture predominantly contains the solvent at least partially comprising carboxylic acid and/or alcohol and/or ketone, which is the aim of the present invention. The specified solvent may have a different chemical nature, it is only necessary that it be resistant to oxidation in the reaction conditions. In particular, selected from a proton polar solvents and aprotic polar solvents. As an example, proton polar solvents can lead carboxylic acid, sodot 2 to 9 carbon atoms, performancebuy acid, such as triperoxonane acid, alcohols, such as tert-butanol. As an example, aprotic polar solvents can lead esters of lower Akilov (in which the alkyl radical contains from 1 to 4 carbon atoms) carboxylic acids, in particular aliphatic carboxylic acids having from 2 to 9 carbon atoms, or performancebuy acids; tetramethylsilane (or sulfolan); acetonitrile; chlorinated hydrocarbons such as dichloromethane; or ketones, such as acetone.

In the oxidation of cyclohexane as a solvent mainly use acetic acid. It is convenient to use the catalyst included in which manganese and chromium are present in the form of compounds which are derivatives of the carboxylic acid, which is used as a solvent, since these compounds are soluble in the reaction mixture. It is for this reason mainly use the acetates of manganese, chromium and iron.

The solvent is usually from 1 wt.% up to 99 wt.% by weight of the reaction mixture, mainly from 10 wt.% up to 90 wt.%, and even more preferably from 20 wt.% up to 80 wt.%.

Processadora, at which conduct the oxidation reaction varies, in particular, depending on the source reagent. It usually ranges from 50C to 200C and preferably from 80 to 140 C.

Pressure is not a critical parameter of the method according to the invention. It can be less than, equal to or greater than atmospheric pressure. In General it ranges from 0.1 MPa (1 bar) up to 20 MPa (200 bar), but these values are not required.

You can use pure oxygen, air, air enriched or depleted in oxygen, or oxygen diluted with an inert gas.

The invention is illustrated below by examples.

Example 1

In a titanium autoclave with a capacity of 1.5 liters, equipped with a tubular heater, cooling system, mixer, feed system and pumping gas and pressure regulator, purged with nitrogen, put:

- 292,5 g of cyclohexane;

- 357 g of acetic acid;

- 3.4 g of cyclohexanone;

- 4,16 g (of 16.7 mmol) acetate tetrahydrate cobalt;

- rate 0.162 g (0,74 mmol CR) chromium acetate dihydrate;

- 1,183 g (3.2 mmol Fe) iron acetylacetonate;

0.8 g of water.

The reactor is closed, stirred the mixture at brasenia mass at a temperature of 105C for 20 minutes. Nitrogen under a pressure of 20 bar is replaced by air containing 5% oxygen. The normal flow of gaseous air is 250 l/h. After a short period of time amounting to several minutes, during which no consumption of oxygen, the temperature rises a few degrees and observed oxygen consumption. The oxygen content in the air is gradually increased up to 21%. The oxygen concentration in the gas leaving the reactor remains below 5%.

After 76 minutes the reaction is consumed 52,8 l oxygen, reduced to normal conditions, which corresponds to a degree of conversion of cyclohexane, approximately 20%.

After the air purge stop, the mass is cooled to a temperature of 70 C and the reaction mixture is subjected to analysis in order to determine the degree of conversion and selectivity of the reaction. These analyses are carried out using gas chromatography (under selectivity understand the percentage molar ratio of the number of moles of a particular type of connection to theoretical number of moles of that compound, calculated from the number of moles effectively subjected to the conversion of cyclohexane).

Get the following results:

- selectivity of cyclohexanone relative to converted to cyclohexane is 4.9%;

- selectivity of adipic acid with respect to converted to cyclohexane 67,1%;

- selectivity of adipic acid + cyclohexanone + cyclohexanol in relation to converted to cyclohexane 78,3%;

- the molar ratio of adipic acid to the total amount of dibasic acids 85,9%.

Example 2 (comparative)

Repeat Example 1 in the same device and under the same conditions, using the following reagents:

- 292,5 g of cyclohexane;

- 357 g of acetic acid;

- 3.4 g of cyclohexanone;

to 4.0 g (16.2 mmol) acetate tetrahydrate cobalt;

- of) 0.157 g (0.64 mmol CR) chromium acetate dihydrate;

0.6 g of water.

The reaction time required to achieve an equivalent degree of conversion is 95 minutes instead of 76 minutes in Example 1.

Get the following results:

the degree of conversion of cyclohexane to 21.1%;

- selectivity of cyclohexanol in relation to converted to cyclohexane 5,1%;

- selectivity of cyclohexanone relative to converted to cyclohexane 3,4%;

- selectivity of adipic acid with respect to po respect to converted to cyclohexane 79,4%;

- the molar ratio of adipic acid to the total number of received duotronic acids of 85.7%.

The specified analysis shows the influence of iron on the catalyst activity. Indeed, to obtain a similar degree of conversion of cyclohexane reaction time in comparison with Example 1 was reduced by 25%, while achieved equivalent selectivity for adipic acid.

Example 3 (comparative)

Repeat Example 1 in the same device and under the same conditions, placing the following reagents:

- 292,5 g of cyclohexane;

- 357 g of acetic acid;

- 3.4 g of cyclohexanone;

- 4,17 g (of 16.7 mmol) acetate tetrahydrate cobalt;

0.8 g of water.

The reaction time is 75 minutes.

Get the following results:

the degree of conversion of cyclohexane 20,3%;

- selectivity of cyclohexanol in relation to converted to cyclohexane of 11.6%;

- selectivity of cyclohexanone relative to converted to cyclohexane 4,5%;

- selectivity of adipic acid with respect to converted to cyclohexane 61,9%;

- selectivity of adipic acid + cyclohexanone + cyclohexanol in relation to developed cyclohexa,4%.

This analysis shows, in comparison with Example 1, a positive effect of the presence of iron and chromium on the selectivity and productivity of the catalyst.

Example 4

Repeat Example 1 in the same device and under the same conditions, using the following reagents:

- 292,5 g of cyclohexane;

- 357 g of acetic acid;

- 3.4 g of cyclohexanone;

- 4,13 g (of 16.6 mmol) acetate tetrahydrate cobalt;

- 0,2325 g (1.06 mmol CR) chromium acetate dihydrate;

- 1,086 g (3.1 mmol Fe) iron acetylacetonate;

0.8 g of water.

The reaction time is 73 minutes.

Get the following results:

the degree of conversion of cyclohexane 20,3%;

- selectivity of cyclohexanol in relation to converted to cyclohexane 9,8%;

- selectivity of cyclohexanone relative to converted to cyclohexane 2,5%;

- selectivity of adipic acid with respect to converted to cyclohexane 68,8%;

- selectivity of adipic acid + cyclohexanone + cyclohexanol in relation to converted to cyclohexane 78,3%;

- the molar ratio of adipic acid to the total amount of dibasic acids 85,3%.

Example 5 (comparative)

Repeat for the x2">- 357 g of acetic acid;

- 3.4 g of cyclohexanone;

to 4.0 g (16,1 mmol) acetate tetrahydrate cobalt;

- 0,309 g (1.25 mmol CR) chromium acetate dihydrate;

0.6 g of water.

The induction period of the reaction is 50 minutes, and the reaction time is 160 minutes.

Get the following results:

the degree of conversion of cyclohexane 17%;

- selectivity of cyclohexanol in relation to converted to cyclohexane 4,6%;

- selectivity of cyclohexanone relative to converted to cyclohexane 1,7%;

- selectivity of adipic acid with respect to converted to cyclohexane 74,3%;

- selectivity of adipic acid + cyclohexanone + cyclohexanol in relation to converted to cyclohexane 77,2%;

- the molar ratio of adipic acid to the total amount of dibasic acids of 83.4%;

This analysis clearly shows, in comparison with Example 4, a positive effect of the combination of iron and chromium in the product yield, the selectivity varies slightly.

Example 6

In a titanium autoclave with a capacity of 1.5 liters, equipped with a tubular heater, cooling system, mixer, feed system and pumping g 357 g of acetic acid;

- to 3.67 g of cyclohexanone;

- 4,13 g (of 16.6 mmol) acetate tetrahydrate cobalt;

- 0,1595 g (0.73 mmol CR) chromium acetate dihydrate;

- 1,0895 g (3.1 mmol Fe) iron acetylacetonate;

0.8 g of water.

The reactor is closed, stirred at a rotation speed of 1000 rpm, is filled with nitrogen under a pressure of 20 bar at 20 C and heat up. Maintain the mass at a temperature of 105C for 20 minutes. Nitrogen under a pressure of 20 bar is replaced by air containing 5% oxygen. The normal flow of gaseous air is 250 l/h. After a short period of time amounting to several minutes, during which no consumption of oxygen, the temperature rises a few degrees and observed oxygen consumption. The oxygen content in the air is gradually increased up to 21%. The oxygen concentration in the gas leaving the reactor remains below 5%.

When absorbed 50 l of oxygen, reduced to normal conditions, which corresponds to a degree of conversion of cyclohexane, approximately 20%, in the liquid phase start continuously feeding speed of 3.9 ml/min a solution of acetic acid containing 1.1 wt.% acetate tetrahydrate cobalt, 0,043 wt.% dihydrate of chromium acetate and 0.3 weight is e-filing is 0.6 l/min

After the air purge and supply of reagents, stop mass is then cooled to a temperature of 70C. The reaction mixture is analyzed to determine different degrees of conversion and selectivity of the reaction. These tests conducted by gas chromatography.

Get the following results:

the degree of conversion of cyclohexane 19,6%;

- selectivity of cyclohexanol in relation to converted to cyclohexane 6,5%;

- selectivity of cyclohexanone relative to converted to cyclohexane 6,0%;

- selectivity of adipic acid with respect to converted to cyclohexane 65,3%;

- selectivity of adipic acid + cyclohexanone + cyclohexanol in relation to converted to cyclohexane 77,8%;

- the molar ratio of adipic acid to the total amount of dibasic acids of 85.1%.

The productivity of the catalyst is of 60.7 g of the obtained adipic acid per liter per hour.

Example 7 (comparative)

Repeat Example 6 in the same device and under the same conditions, except that in the initial download and the feed solution does not use iron.

The consumption of oxygen in the submission process is 0,aktivnosti cyclohexanol in relation to converted to cyclohexane 5,1%;

- selectivity of cyclohexanone relative to converted to cyclohexane 4,8%;

- selectivity of adipic acid with respect to converted to cyclohexane 69,5%;

- selectivity of adipic acid + cyclohexanone + cyclohexanol in relation to converted to cyclohexane 79,4%;

- the molar ratio of adipic acid to the total amount of dibasic acids 85,0%.

The productivity of the catalyst is 47.5 g of adipic acid per liter per hour.

Example 8 (comparative)

Repeat Example 7 in the same device and under the same conditions, except that in the initial download and the feed solution does not use iron and chromium.

Oxygen consumption in the process of filing 0,55 l/min

Get the following results:

the degree of conversion of cyclohexane 18.5%; and

- selectivity of cyclohexanol in relation to converted to cyclohexane 10,8%;

- selectivity of cyclohexanone relative to converted to cyclohexane 5,8%;

- selectivity of adipic acid with respect to converted to cyclohexane 61,6%;

- selectivity of adipic acid + cyclohexanone + cyclohexanol in relation to puff the dibasic acids of 84.0%.

The productivity of the catalyst is of 56.5 g of adipic acid per liter per hour.

Example 9 (comparative)

In a titanium autoclave with a capacity of 125 ml, equipped with a tubular heater, a stirrer, a gas supply system and pressure regulator, put:

- each holding 21.25 g (253 mmol) of cyclohexane;

- 27,35 g of acetic acid;

- 0.26 g (to 2.65 mmol) cyclohexanone;

- 0,0357 g (0,146 mmol MP) acetate tetrahydrate manganese;

- to 0.011 g of dihydrate of chromium acetate (0.04 mmol Cr).

The reactor is closed, stirred the mixture at a rotation speed of 1000 rpm, fill the reactor with air under a pressure of 100 bar at 20 C) and heat up. The temperature of the mixture increased to 105C for 10 minutes and then kept at this temperature for 150 minutes.

After cooling and reducing the pressure get the reaction mixture into two liquid phases, and it homogenized by adding acetic acid.

Thus obtained homogeneous mixture was analyzed by gas chromatography.

Get the following results:

the degree of conversion of cyclohexane to 14.9%;

- selectivity of cyclohexanol in relation to converted to cyclohexane and 19.4%;

- selectionist respect to converted to cyclohexane 50%;

- selectivity of adipic acid + cyclohexanone + cyclohexanol in relation to converted to cyclohexane 69,4%;

- the molar ratio of adipic acid to the total amount of dibasic acids and 77.6%;

Example 10

Repeat Example 9, using the catalytic system of the following composition:

- 0,3107 g (1,247 mmol) acetate tetrahydrate cobalt;

- 0,0119 g (0.012 mmol CR) chromium acetate dihydrate;

- 0,0861 g (0,244 mmol Fe) iron acetylacetonate;

- 0,0525 g (0,149 mmol MP) acetylacetonate and manganese (III).

The mixture was kept at a temperature of 105C for 45 minutes.

Get the following results:

the degree of conversion of cyclohexane to 12.1%;

- selectivity of cyclohexanol in relation to converted to cyclohexane 9,5%;

- selectivity of cyclohexanone relative to converted to cyclohexane 8,1;

- selectivity adipine acid relative to converted to cyclohexane 67%;

- selectivity of adipic acid + cyclohexanone + cyclohexanol in relation to converted to cyclohexane 85,6%;

- the molar ratio of adipic acid to the total amount of dibasic acids of 85.5%.

- 0,3135 g (amount of 1, 258 mmol) acetate tetrahydrate cobalt;

- 0,0114 g (0,0113 mmol CR) chromium acetate dihydrate;

- 0,0828 g (0,234 mmol Fe) iron acetylacetonate;

- 0,0522 g (0,148 mmol MP) acetylacetonate and manganese (III);

- 0,0059 g (0,0121 mmol Zr) zirconium acetylacetonate.

Get the following results:

the degree of conversion of cyclohexane to 11.7%;

- selectivity of cyclohexanol in relation to converted to cyclohexane 8,8%;

- selectivity of cyclohexanone relative to converted to cyclohexane 9,4%;

- selectivity of adipic acid with respect to converted to cyclohexane 67,4%;

- selectivity of adipic acid + cyclohexanone + cyclohexanol in relation to converted to cyclohexane 85,6%;

- the molar ratio of adipic acid to the total amount of dibasic acids of 85.7%.

1. The method of oxidation of cyclic hydrocarbons, alcohols and/or ketones to carboxylic acids with oxygen or oxygen-containing gas, which is carried out in the liquid phase in a solvent, which is selected from a proton polar solvents and aprotic polar solvents and in the presence of a catalyst soluble in the reaction with storymode the chromium compound and one soluble compound of iron, the amount of catalyst in the reaction mixture is 0.0001-5 %, primarily of 0.001-2 wt.% with respect to the reaction mixture.

2. The method according to p. 1, wherein the cyclic hydrocarbon that is used as a starting compound, selected from cycloalkanes having a cycle comprising from 5 to 12 carbon atoms, and preferably using cyclohexane.

3. The method according to p. 1, wherein the cyclic alcohol and/or ketone used as starting compounds, selected from cycloalkanones and cycloalkanones having a cycle comprising from 5 to 12 carbon atoms, preferably using cyclohexanol and/or cyclohexanone.

4. The method according to any of paragraphs.1-3, characterized in that the catalyst contains at least one compound of manganese, soluble in the reaction medium, which is selected from manganese chloride, manganese bromide, manganese nitrate and manganese carboxylates such as acetate tetrahydrate manganese propionate, manganese, adipate manganese, glutarate manganese, manganese succinate.

5. The method according to any of paragraphs.1-4, characterized in that the catalyst contains at least one compound of cobalt, dissolved in the reaction medium, which viber is the cobalt propionate, adipate cobalt, glutarate cobalt, cobalt succinate.

6. The method according to any of paragraphs.1-5, characterized in that the catalyst contains at least one chromium compound soluble in the reaction medium, which is selected from chromium chloride, chromium bromide, chromium nitrate and chromium carboxylates such as chromium acetate, chromium propionate, adipate chromium, glutarate chromium, succinate chromium, a mineral or organic salts of chromic acid.

7. The method according to any of paragraphs.1-6, characterized in that the catalyst contains at least one compound of iron, soluble in the reaction medium, which is selected from ferric chloride, iron bromide, iron nitrate and iron carboxylates such as acetate of iron, iron propionate, adipate iron, glutarate iron, iron succinate.

8. The method according to any of paragraphs.1-7, characterized in that the catalyst contains one soluble compound of zirconium.

9. The method according to p. 8, characterized in that the compound of zirconium, soluble in the reaction medium, selected from zirconium chloride, zirconium bromide, zirconium nitrate and zirconium carboxylates such as zirconium acetate, zirconium propionate, adipate zirconium, glutarate zirconium, succinate by lancem and/or cobalt, chromium and iron in the range of from 1/0,00001/0,0001 to 1/100/100.

11. The method according to p. 10, characterized in that the use of molar ratio between the manganese and/or cobalt, chromium and iron in the range of from 1/0,001/0,001 to 1/10/10.

12. The method according to any of paragraphs.1-11, characterized in that the liquid reaction mixture contains a solvent chosen from aliphatic carboxylic acids having from 2 to 9 carbon atoms, performancebuy acids, alcohols, halogenated hydrocarbons, ketones, complex lower alilovic esters of carboxylic acids, predominantly aliphatic carboxylic acids having from 2 to 9 carbon atoms, or performancebuy acids, tetramethylsilane (or sulfolane, acetonitrile.

13. The method according to any of paragraphs.1-12, characterized in that the solvent used acetic acid.

14. The method according to any of paragraphs.1-13, characterized in that the solvent is from 1 to 99% by weight of the reaction mixture, mainly from 10 to 90%.

15. The method according to any of paragraphs.1-14, characterized in that the temperature at which conduct the oxidation reaction, is from 50 to 200C and preferably from 80 to 140 C.

16. The method according to any of paragraphs.1-15, characterized in that the pressure is

 

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The invention relates to a method for selective separation of iron from other metal ions, in particular ions contained in some oxidation catalysts

The invention relates to an improved method of isolation and purification of adipic acid, used for the production of polyamide-6,6 or polyurethanes, which consists in treating the reaction mixture obtained by direct oxidation of cyclohexane to adipic acid by molecular oxygen in an organic solvent and in the presence of a catalyst, removing by-products from the reaction mixture and the adipic acid by crystallization, and before adipic acid from the reaction environment carry out consistently the following operations: the decantation of the two phases of the reaction medium with the formation of the upper organic the cyclohexane phase, containing mainly cyclohexane, and the lower phase, containing mainly the solvent, the resulting dicarboxylic acid, the catalyst and other reaction products and unreacted cyclohexane; distillation bottom phase to separate, on the one hand, distillate containing at least a part of the most volatile compounds, such as organic solvent, water and unreacted cyclohexane, cyclohexanone, cyclohexanol, complex cyclohexylamine esters and possibly lactones, and, with the pin acid from residue from distillation by means of crystallization and thus obtained crude adipic acid is subjected in aqueous solution purification by hydrogenation and/or oxidation with subsequent crystallization and recrystallization of the purified adipic acid in water
The invention relates to an improved method of liquid-phase oxidation of cycloalkanes, cycloalkanones and/or cycloalkanones to carboxylic acids, in particular cyclohexane to adipic acid used to obtain the polyamide 6-6

The invention relates to the treatment of the reaction mixtures formed during the oxidation of cyclohexane to adipic acid

The invention relates to a method for producing ester of formic acid or methanol and the catalyst of this method
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