Method for removing oxidation by-products from cyclohexylbenzene oxidation product liquid and its application

Abstract

The present invention provides a method for removing cyclohexylbenzene oxidation product liquid and its application. The method comprises the following steps: extracting and separating the cyclohexylbenzene oxidation product liquid using an extractant; the extractant comprises water and a saturated fatty acid having 1 to 6 carbon atoms. The method can effectively remove the main oxidation byproducts from the cyclohexylbenzene oxidation product liquid and is simple and easy to perform.

Description

Technical Field

[0001] The invention belongs to the technical field of phenol, and particularly relates to a method for removing oxidation by-products in cyclohexylbenzene oxidation product liquid and application thereof. Background Art

[0002] Phenol is an important chemical raw material. Its downstream products, such as bisphenol A, phenolic resins, caprolactam, plasticizers, and polymers such as nylon-6, are widely used in the automotive, construction, and telecommunications industries. Currently, the most common industrial route for producing phenol is the Hock process with cumene. Specifically, propylene and benzene are first reacted with an acidic catalyst to produce cumene, which is then oxidized with air to form cumene peroxide. This is then decomposed with a mineral acid or acidic resin to produce essentially equimolar quantities of phenol and acetone. This route has the advantages of inexpensive, readily available raw materials and continuous production. However, the market demand for its co-product, acetone, is growing less than that for phenol. Therefore, replacing the Hock process's starting raw material with cyclohexylbenzene is a more promising process for producing the more economically efficient phenol and cyclohexanone.

[0003] The air oxidation of cyclohexylbenzene (CHB) is a typical free radical chain reaction. Compared to cumene, the cyclohexylbenzene-1-hydroperoxide that ultimately produces phenol upon acidolysis suffers from the steric hindrance of tertiary hydrogen atoms sandwiched between the benzene ring and the cyclohexyl group. This leads to competition between the secondary carbon atoms and hydrogen atoms on the cyclohexyl group, resulting in the formation of non-tertiary peroxides or even multiple peroxides. Furthermore, the peroxide itself undergoes intracyclic hydrogen rearrangement and transfer. These two factors together lead to numerous side reactions and low selectivity in CHB oxidation.

[0004] In industry, all or a portion of the oxidation solution is typically recycled back to the oxidation reactor at a relatively low oxidation depth to improve overall reaction conversion. However, as the number of cycles increases, if the oxidation solution is not treated, trace amounts of oxidation byproducts will gradually accumulate, eventually causing the oxidation reaction to gradually slow down and eventually stop.

[0005] Currently, distillation is commonly used to remove oxidation byproducts (such as 1-phenylcyclohexanol and hexanophenone) from the cyclohexylbenzene oxidation product liquid. However, cyclohexylbenzene and these oxidation byproducts have high and similar boiling points (>250°C), which makes high vacuum distillation to separate impurities economically expensive or requires very high temperatures, which may lead to the risk of uncontrolled and dangerous peroxide thermal decomposition. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to address the technical problems existing in the prior art and provide a method for removing oxidation by-products in cyclohexylbenzene oxidation product liquid and its application. The removal method of the present invention can effectively remove the main oxidation by-products from the cyclohexylbenzene oxidation product liquid and is simple and easy to implement.

[0007] The objectives of the present invention are achieved through the following technical solutions.

[0008] In a first aspect, the present invention provides a method for removing oxidation by-products from cyclohexylbenzene oxidation product liquid, wherein the removal method comprises the following steps: extracting and separating the cyclohexylbenzene oxidation product liquid using an extractant; the extractant contains water and a saturated fatty acid with 1 to 6 carbon atoms.

[0009] In the present invention, the terms "oxidation product liquid" and "oxidation liquid" can be used interchangeably, both referring to the cyclohexylbenzene oxidation product liquid.

[0010] In the process of preparing cyclohexylbenzene-1-hydroperoxide by air oxidation of cyclohexylbenzene, the oxidation generated liquid can produce 3-5% by weight of main oxidation byproducts (1-phenylcyclohexanol and hexanone) after about 3-4 cycles, which seriously affects the carrying out of the oxidation reaction. Therefore, it is extremely important to remove the oxidation byproducts in the oxidation liquid. The inventors of the present application have found that by adding an extractant containing water and a saturated fatty acid having 1-6 carbon atoms to the cyclohexylbenzene oxidation generated liquid to extract, the oxidation byproducts (such as alcohol and / or ketone) in the cyclohexylbenzene oxidation generated liquid enter the aqueous phase, while cyclohexylbenzene and cyclohexylbenzene hydroperoxide (particularly cyclohexylbenzene-1-hydroperoxide) remain in the oil phase, thereby achieving the removal of the oxidation byproducts.

[0011] According to the removal method provided by the present invention, the cyclohexylbenzene oxidation product liquid contains at least 50% by weight of cyclohexylbenzene. In some embodiments, the cyclohexylbenzene oxidation product liquid contains 50-90% by weight of cyclohexylbenzene; in some embodiments, the cyclohexylbenzene content is 60-90% by weight; and in some embodiments, the cyclohexylbenzene content is 70-85% by weight.

[0012] According to the removal method provided by the present invention, the content of cyclohexylbenzene hydroperoxide in the cyclohexylbenzene oxidation product liquid is 10 to 40% by weight, preferably 15 to 30% by weight.

[0013] According to the removal method provided by the present invention, the cyclohexylbenzene hydroperoxide includes cyclohexylbenzene-1-hydroperoxide.

[0014] In some embodiments, based on the weight of the cyclohexylbenzene hydroperoxide, the cyclohexylbenzene hydroperoxide comprises at least 80% by weight of cyclohexylbenzene-1-hydroperoxide; in some embodiments, at least 85% by weight of cyclohexylbenzene-1-hydroperoxide; in some embodiments, at least 90% by weight of cyclohexylbenzene-1-hydroperoxide; and in some embodiments, at least 95% by weight of cyclohexylbenzene-1-hydroperoxide.

[0015] According to the removal method provided by the present invention, the cyclohexylbenzene oxidation product solution contains at least 1 weight percent of oxidation by-products. In some embodiments, the content of oxidation by-products in the cyclohexylbenzene oxidation product solution is 1 to 10 weight percent; in some embodiments, 5 to 10 weight percent; and in some embodiments, 5 to 8 weight percent.

[0016] According to the removal method provided by the present invention, the oxidation byproducts include alcohols and / or ketones, the alcohol is usually 1-phenylcyclohexanol, and the ketone is usually hexanophenone.

[0017] In some embodiments, the content of 1-phenylcyclohexanol in the cyclohexylbenzene oxidation product liquid is 0.5 to 5% by weight, preferably 1 to 3% by weight.

[0018] In some embodiments, the content of hexanophenone in the cyclohexylbenzene oxidation product liquid is 0.5 to 8 weight %, preferably 4 to 6 weight %.

[0019] According to the removal method provided by the present invention, the saturated fatty acid is a saturated fatty acid having 1 to 3 carbon atoms. Examples of saturated fatty acids suitable for use in the present invention include, but are not limited to, formic acid, acetic acid, and propionic acid. In some embodiments, the saturated fatty acid includes acetic acid; and in some embodiments, the saturated fatty acid further includes at least one selected from formic acid and propionic acid.

[0020] In some specific embodiments, the content of acetic acid may be 50 to 100 weight % based on the weight of the saturated fatty acid.

[0021] According to the removal method provided by the present invention, the content of the saturated fatty acids in the extractant is 50 to 99 weight %. The content of the saturated fatty acids in the extractant can be 50 weight %, 60 weight %, 70 weight %, 80 weight %, 90 weight %, 95 weight %, 96 weight %, 97 weight %, 98 weight %, 99 weight %, or a range thereof. In some embodiments, the content of the saturated fatty acids in the extractant is 80 to 99 weight %; in some embodiments, 90 to 99 weight %; in some embodiments, 90 to 98 weight %; and in some embodiments, 95 to 98 weight %.

[0022] According to the removal method provided by the present invention, the water content in the extractant is 1 to 50% by weight. The water content in the extractant can be 1% by weight, 2% by weight, 3% by weight, 4% by weight, 5% by weight, 10% by weight, 20% by weight, 30% by weight, 40% by weight, 50% by weight, or a range thereof. In some embodiments, the water content in the extractant is 1 to 20% by weight; in some embodiments, 1 to 10% by weight; in some embodiments, 2 to 10% by weight; and in some embodiments, 2 to 5% by weight.

[0023] According to the removal method provided by the present invention, the cyclohexylbenzene oxidation product liquid is extracted with the extractant for 1 to 5 times, preferably 2 to 4 times.

[0024] According to the removal method provided by the present invention, during each extraction, the weight ratio of the extractant to the cyclohexylbenzene oxidation product liquid is 0.3 to 3:1, preferably 0.5 to 2:1, and more preferably 0.8 to 1.2:1.

[0025] According to the removal method provided by the present invention, the cyclohexylbenzene oxidation product liquid is an oxidation product liquid obtained by air oxidation reaction of cyclohexylbenzene in the presence of an imide catalyst.

[0026] In the present invention, the removal method further comprises the following step: prior to extraction, washing the oxidation product liquid with water or an aqueous solution containing an alkali metal carbonate and / or bicarbonate, thereby removing at least a portion of the imide catalyst and further reducing imide and other water-soluble impurities.

[0027] Examples of alkali metal carbonates and / or bicarbonates suitable for use in the present invention include, but are not limited to, sodium carbonate, potassium carbonate, sodium bicarbonate, and potassium bicarbonate.

[0028] In the present invention, the concentration of the aqueous solution containing the alkali metal carbonate and / or hydrogen carbonate may be 1 to 15% by weight, and preferably 8 to 12% by weight.

[0029] In the present invention, there is no particular requirement for the amount of water or the aqueous solution containing an alkali metal carbonate and / or bicarbonate used during washing. In some embodiments, the amount of water or the aqueous solution containing an alkali metal carbonate and / or bicarbonate used is 0.3 to 2 times, preferably 0.5 to 1 times, the weight of the oxidation product solution.

[0030] In a second aspect, the present invention provides application of the removal method in the oxidation of cyclohexylbenzene to produce cyclohexylbenzene-1-hydroperoxide.

[0031] According to the application provided by the present invention, the application includes the following steps: mixing the cyclohexylbenzene oxidation product liquid treated by the removal method with cyclohexylbenzene and performing air oxidation to prepare cyclohexylbenzene-1-hydroperoxide.

[0032] According to the application provided by the present invention, the weight ratio of the cyclohexylbenzene oxidation product liquid after treatment by the removal method to cyclohexylbenzene is 1-30:99-70, preferably 10-20:90-80.

[0033] The present invention has the following advantages: the removal method of the present invention can effectively separate and remove the main oxidation by-products from the cyclohexylbenzene oxidation product liquid, is simple and easy to implement, and is particularly suitable for the process of preparing cyclohexylbenzene-1-hydroperoxide by air oxidation of cyclohexylbenzene. DETAILED DESCRIPTION

[0034] The present invention will be further described below with reference to specific examples, but they do not constitute any limitation to the present invention.

[0035] Preparation Example

[0036] (1) 100 g of cyclohexylbenzene, 0.5 g of N-hydroxyphthalimide (NHPI) and 0.05 g of anhydrous sodium carbonate were added to a reactor and reacted at 95°C with air bubbling for 24 h.

[0037] (2) 10 g of the reaction solution prepared in step (1) was mixed with 90 g of cyclohexylbenzene, 0.5 g of NHPI and 0.05 g of anhydrous sodium carbonate were added, and the mixture was reacted at 95° C. with air bubbling for 24 h.

[0038] (3) The oxidation cycle was continued for 5 times to obtain an oxidation liquid after multiple oxidation cycles, to which 50 g of a 10 wt % sodium carbonate aqueous solution was added for washing to obtain an oxidation liquid after multiple oxidation cycles after water washing.

[0039] HPLC analysis showed that the composition of the oxidation liquid after multiple oxidation cycles after water washing was as follows: 65.53 wt % cyclohexylbenzene, 25.25 wt % cyclohexylbenzene-1-hydroperoxide, 1.97 wt % hexanophenone and 5.14 wt % 1-phenylcyclohexanol.

[0040] Example 1

[0041] 1. Separation of cyclohexylbenzene oxidation product liquid

[0042] 100 g of the oxidized solution after multiple cycles of oxidation (containing 65.53 g of cyclohexylbenzene, 25.25 g of cyclohexylbenzene-1-hydroperoxide, 1.97 g of hexanophenone, and 5.14 g of 1-phenylcyclohexanol) after washing with water was added to 98 g of acetic acid and 2 g of water. The mixture was stirred at room temperature for 1 hour and then allowed to stand for separation. HPLC analysis of the oil layer revealed the following composition: 64.00 g of cyclohexylbenzene, 24.60 g of cyclohexylbenzene-1-hydroperoxide, 1.52 g of hexanophenone, and 3.20 g of 1-phenylcyclohexanol.

[0043] The oil phase was extracted three times to obtain a treated oxidation solution, which was analyzed by HPLC and had the following composition: 60.60 g of cyclohexylbenzene, 23.71 g of cyclohexylbenzene-1-hydroperoxide, 0.84 g of hexanophenone, and 1.30 g of 1-phenylcyclohexanol.

[0044] 2. Cyclic oxidation to prepare cyclohexylbenzene-1-hydroperoxide

[0045] 10 g of the treated oxidizing solution was mixed with 90 g of cyclohexylbenzene, 0.5 g of NHPI and 0.05 g of anhydrous sodium carbonate were added, and the mixture was reacted by air bubbling at 95° C. for 24 h. The concentration of cyclohexylbenzene-1-hydroperoxide in the obtained reaction solution was 26.7 wt %.

[0046] Example 2

[0047] 1. Separation of cyclohexylbenzene oxidation product liquid

[0048] 100 g of the oxidized solution after multiple oxidation cycles as in Example 1 was added to 95 g of propionic acid and 5 g of water. The mixture was stirred at room temperature for 1 hour and then allowed to stand for separation. HPLC analysis of the oil layer revealed the following composition: 58.90 g of cyclohexylbenzene, 24.81 g of cyclohexylbenzene-1-hydroperoxide, 1.80 g of hexanophenone, and 3.19 g of 1-phenylcyclohexanol.

[0049] The oil phase was extracted three times to obtain a treated oxidation solution, which was analyzed by HPLC and had the following composition: 47.85 g of cyclohexylbenzene, 23.88 g of cyclohexylbenzene-1-hydroperoxide, 1.50 g of hexanophenone and 1.23 g of 1-phenylcyclohexanol.

[0050] 2. Cyclic oxidation to prepare cyclohexylbenzene-1-hydroperoxide

[0051] 10 g of the treated oxidizing solution was mixed with 90 g of cyclohexylbenzene, 0.5 g of NHPI and 0.05 g of anhydrous sodium carbonate were added, and the mixture was reacted by air bubbling at 95° C. for 24 h. The concentration of cyclohexylbenzene-1-hydroperoxide in the obtained reaction solution was 20.3 wt %.

[0052] Example 3

[0053] 1. Separation of cyclohexylbenzene oxidation product liquid

[0054] 100 g of the oxidized solution after multiple oxidation cycles as in Example 1 was added to 48 g of acetic acid, 48 g of propionic acid, and 4 g of water. The mixture was stirred at room temperature for 1 hour and then allowed to stand for separation. HPLC analysis of the oil layer revealed the following composition: 63.60 g of cyclohexylbenzene, 24.77 g of cyclohexylbenzene-1-hydroperoxide, 1.22 g of hexanophenone, and 3.05 g of 1-phenylcyclohexanol.

[0055] The oil phase was extracted three times to obtain a treated oxidation solution, which was analyzed by HPLC and had the following composition: 59.97 g of cyclohexylbenzene, 23.84 g of cyclohexylbenzene-1-hydroperoxide, 0.50 g of hexanophenone and 1.13 g of 1-phenylcyclohexanol.

[0056] 2. Cyclic oxidation to prepare cyclohexylbenzene-1-hydroperoxide

[0057] 10 g of the treated oxidizing solution was mixed with 90 g of cyclohexylbenzene, 0.5 g of NHPI and 0.05 g of anhydrous sodium carbonate were added, and the mixture was reacted by air bubbling at 95° C. for 24 h. The concentration of cyclohexylbenzene-1-hydroperoxide in the obtained reaction solution was 26.9 wt %.

[0058] Comparative Example 1

[0059] 10 g of the same oxidation solution after multiple cycles of oxidation as in Example 1 was mixed with 90 g of cyclohexylbenzene, 0.5 g of NHPI and 0.05 g of anhydrous sodium carbonate were added, and the mixture was reacted by air bubbling at 95° C. for 24 h. The concentration of cyclohexylbenzene-1-hydroperoxide in the obtained reaction solution was 15.5 wt %.

[0060] Therefore, the removal method of the present invention can effectively remove the main oxidation by-products from the cyclohexylbenzene oxidation product liquid, and the cyclohexylbenzene oxidation product liquid treated by the removal method can be recycled and used in the process of preparing cyclohexylbenzene-1-hydroperoxide by air oxidation of cyclohexylbenzene, and has an improved cyclohexylbenzene-1-hydroperoxide concentration.

[0061] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation of the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein. On the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A method for removing oxidation by-products from cyclohexylbenzene oxidation product liquid, wherein: The removal method comprises the following steps: extracting and separating the cyclohexylbenzene oxidation product liquid with an extractant; the extractant comprises water and a saturated fatty acid, and the saturated fatty acid is selected from at least one of formic acid, acetic acid and propionic acid; The oxidation by-products include 1-phenylcyclohexanol and / or hexanophenone.

2. The removal method according to claim 1, characterized in that The content of cyclohexylbenzene in the cyclohexylbenzene oxidation product liquid is at least 50% by weight.

3. The removal method according to claim 2, characterized in that: The content of cyclohexylbenzene in the cyclohexylbenzene oxidation product liquid is 50 to 90 weight %.

4. The removal method according to claim 3, characterized in that: The content of cyclohexylbenzene in the cyclohexylbenzene oxidation product liquid is 60 to 90 weight %.

5. The removal method according to claim 4, characterized in that: The content of cyclohexylbenzene in the cyclohexylbenzene oxidation product liquid is 70-85% by weight.

6. The removal method according to any one of claims 1 to 5, characterized in that The content of cyclohexylbenzene hydroperoxide in the cyclohexylbenzene oxidation product liquid is 10 to 40% by weight.

7. The removal method according to claim 6, characterized in that: The content of cyclohexylbenzene hydroperoxide in the cyclohexylbenzene oxidation product liquid is 15 to 30% by weight; and / or The cyclohexylbenzene hydroperoxide comprises at least 80 wt% cyclohexylbenzene-1-hydroperoxide, based on the weight of the cyclohexylbenzene hydroperoxide.

8. The removal method according to claim 7, characterized in that: The cyclohexylbenzene hydroperoxide comprises at least 85 wt% cyclohexylbenzene-1-hydroperoxide, based on the weight of the cyclohexylbenzene hydroperoxide.

9. The removal method according to claim 8, characterized in that: The cyclohexylbenzene hydroperoxide comprises at least 90 wt% cyclohexylbenzene-1-hydroperoxide, based on the weight of the cyclohexylbenzene hydroperoxide.

10. The removal method according to claim 9, characterized in that: The cyclohexylbenzene hydroperoxide comprises at least 95 wt% cyclohexylbenzene-1-hydroperoxide, based on the weight of the cyclohexylbenzene hydroperoxide.

11. The removal method according to any one of claims 1 to 5, characterized in that: The cyclohexylbenzene oxidation product liquid contains at least 1 wt% of oxidation by-products; and / or The content of 1-phenylcyclohexanol in the cyclohexylbenzene oxidation product liquid is 0.5 to 5% by weight; and / or The content of hexanophenone in the cyclohexylbenzene oxidation product liquid is 0.5-8% by weight.

12. The removal method according to claim 11, characterized in that: The cyclohexylbenzene oxidation product liquid contains 1 to 10 weight % of oxidation by-products; and / or The content of 1-phenylcyclohexanol in the cyclohexylbenzene oxidation product liquid is 1 to 3% by weight; and / or The content of hexanophenone in the cyclohexylbenzene oxidation product liquid is 4-6% by weight.

13. The removal method according to claim 12, characterized in that: The cyclohexylbenzene oxidation product liquid contains 5 to 10 weight percent of oxidation by-products.

14. The removal method according to claim 13, characterized in that: The cyclohexylbenzene oxidation product liquid contains 5 to 8 weight percent of oxidation by-products.

15. The removal method according to any one of claims 1 to 5, characterized in that The saturated fatty acid includes acetic acid and optionally at least one selected from formic acid and propionic acid.

16. The removal method according to claim 15, characterized in that: The content of acetic acid is 50 to 100 weight % based on the weight of the saturated fatty acid.

17. The removal method according to any one of claims 1 to 5, characterized in that The content of the saturated fatty acid in the extractant is 50 to 99% by weight; and / or The water content in the extractant is 1 to 50% by weight.

18. The removal method according to claim 17, characterized in that: The content of the saturated fatty acid in the extractant is 80 to 99% by weight; and / or The water content in the extractant is 1 to 20% by weight.

19. The removal method according to claim 18, characterized in that: The content of the saturated fatty acid in the extractant is 90 to 99% by weight; and / or The water content in the extractant is 1 to 10% by weight.

20. The removal method according to claim 19, characterized in that: The content of the saturated fatty acid in the extractant is 90-98% by weight; and / or The water content in the extractant is 2-10% by weight.

21. The removal method according to claim 20, characterized in that: The content of the saturated fatty acid in the extractant is 95-98% by weight; and / or The water content in the extractant is 2-5% by weight.

22. The removal method according to any one of claims 1 to 5, characterized in that The cyclohexylbenzene oxidation product liquid is extracted 1 to 5 times with the extractant; and / or during each extraction, the weight ratio of the extractant to the cyclohexylbenzene oxidation product liquid is 0.3 to 3:

1.

23. The removal method according to claim 22, characterized in that: The cyclohexylbenzene oxidation product liquid is extracted 2 to 4 times with the extractant; and / or during each extraction, the weight ratio of the extractant to the cyclohexylbenzene oxidation product liquid is 0.5 to 2:

1.

24. The removal method according to claim 23, characterized in that: During each extraction, the weight ratio of the extractant to the cyclohexylbenzene oxidation product liquid is 0.8-1.2:

1.

25. Use of the removal method according to any one of claims 1 to 24 in the production of cyclohexylbenzene-1-hydroperoxide by oxidation of cyclohexylbenzene.

26. The use according to claim 25, characterized in that The application The method comprises the following steps: mixing the cyclohexylbenzene oxidation product liquid treated by the removal method with cyclohexylbenzene and performing air oxidation to prepare cyclohexylbenzene-1-hydroperoxide.

27. The use according to claim 26, characterized in that The weight ratio of the cyclohexylbenzene oxidation product liquid to the cyclohexylbenzene after treatment by the removal method is 1-30:99-70.

28. The use according to claim 27, characterized in that The weight ratio of the cyclohexylbenzene oxidation product liquid treated by the removal method to the cyclohexylbenzene is 10-20:90-80.