Process for the production of high purity isopropanol by hydrogenation of dimethyl ketone

Abstract

This invention relates to the field of high-purity isopropanol preparation technology, and discloses a method for preparing isopropanol by hydrogenation of dimethyl ketone. The method includes: (1) purifying dimethyl ketone raw material to obtain purified dimethyl ketone; (2) reacting the purified dimethyl ketone with hydrogen in the presence of a hydrogenation catalyst to obtain isopropanol product; (3) refining the crude isopropanol product to obtain the high-purity isopropanol; wherein, in step (1), the purification method includes refining the dimethyl ketone raw material after contacting it with an oxidant; the amount of the oxidant is 0.01-0.05 wt% of the dimethyl ketone raw material; and the concentration of organic acids in the purified dimethyl ketone is less than or equal to 20 ppm. By controlling the concentration of organic acids in the purified dimethyl ketone reacting with hydrogen to be less than or equal to 20 ppm, the selectivity and content of isopropanol in the isopropanol product during the hydrogenation reaction can be increased, and the content of impurities, especially ether impurities, in the isopropanol product can be reduced.

Description

Technical Field

[0001] This invention relates to the field of high-purity isopropanol preparation technology, specifically to a method for preparing high-purity isopropanol by hydrogenation of dimethyl ketone. Background Technology

[0002] Isopropanol is the most widely used organic solvent in wet electronic chemicals, primarily for cleaning and drying. Isopropanol used in integrated circuits has strict requirements regarding the content of trace organic impurities, metal cation impurities, particle size and quantity, and anionic impurities. With the rapid commissioning of wafer fabs and continuous breakthroughs in advanced integrated circuit process nodes, the demand for G4-G5 high-grade isopropanol is gradually increasing.

[0003] The main methods for producing isopropanol include the hydrogenation of dimethyl ketone and the hydration of propylene, with the former accounting for a larger proportion. To obtain high-purity isopropanol, it is necessary to purify the impurities in the dimethyl ketone raw material. This involves pre-purifying the raw material, intervening in the reaction, inhibiting side reactions, and reducing organic impurities that are difficult to separate from isopropanol, thereby obtaining high-purity isopropanol. Summary of the Invention

[0004] The purpose of this invention is to overcome the problems of excessive ether impurities and low selectivity of isopropanol in the isopropanol product during the preparation of isopropanol using dimethyl ketone in the prior art, and to provide a method for preparing isopropanol by hydrogenation of dimethyl ketone.

[0005] Commercially available dimethyl ketones contain some impurities. In existing processes for preparing isopropanol using dimethyl ketones, the dimethyl ketone is typically purified by simple dehydration before hydrogenation. The purpose of purifying dimethyl ketones is to remove impurities that are difficult to separate from isopropanol through hydrogenation. The inventors discovered that organic acids are generated during the removal of these impurities, and that these organic acids can be hydrogenated to form alcohols. Furthermore, they found that these organic acids promote the etherification side reaction of isopropanol, thereby reducing the selectivity of isopropanol and the content of isopropanol in the isopropanol product. This increases the difficulty of isopropanol purification and places higher demands on equipment and operating procedures.

[0006] The first aspect of this invention provides a method for preparing high-purity isopropanol by hydrogenation of dimethyl ketone, the method comprising:

[0007] (1) Dimethyl ketone raw material is purified to obtain purified dimethyl ketone; (2) in the presence of a hydrogenation catalyst, purified dimethyl ketone is hydrogenated with hydrogen to obtain isopropanol product; (3) crude isopropanol product is purified to obtain the high-purity isopropanol; wherein, in step (1), the purification method includes purification after contacting dimethyl ketone raw material with an oxidant; the amount of the oxidant is 0.01-0.05 wt% of dimethyl ketone raw material; the concentration of organic acid in purified dimethyl ketone is less than or equal to 20 ppm.

[0008] Preferably, the concentration of organic acid in the purified dimethyl ketone is less than or equal to 2 ppm.

[0009] Preferably, the organic acid contains a carboxyl group, and preferably includes one or more of formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, and isovaleric acid.

[0010] Preferably, in step (1), the refining method includes one or more of the following: distillation, fractional distillation, reactive distillation, chemical deacidification of dimethyl ketone, deacidification resin, dimethyl ketone extraction, dimethyl ketone salt formation, and dimethyl ketone dehydration.

[0011] Preferably, in step (1), the refining method includes distillation and dehydration.

[0012] Preferably, in step (1), the purification method includes: contacting the dimethyl ketone raw material with an oxidant, followed by dehydration and distillation.

[0013] Preferably, the fraction collected at 54-58°C during distillation is used as the purified dimethyl ketone;

[0014] Preferably, the distillation conditions include: atmospheric pressure - 1 bar; and a bottom temperature of 72-76°C.

[0015] Preferably, the dehydration method includes: the dimethyl ketone raw material is contacted with an oxidant to obtain dimethyl ketone, which is then fed into a dehydration tower filled with a dehydrating agent for dehydration to obtain dimethyl ketone with a water content of less than 1500 ppm.

[0016] Preferably, the dehydrating agent comprises one or more of molecular sieves, silica gel, activated alumina, and salts that can form crystalline hydrates.

[0017] Preferably, the conditions for contact between the dimethyl ketone raw material and the oxidant include: atmospheric pressure; temperature of 10-40°C, preferably 20-30°C.

[0018] Preferably, the contact conditions between the dimethyl ketone raw material and the oxidant include a time of 0.5-10 hours, preferably 3-8 hours.

[0019] Preferably, the oxidant includes one or more of the following: metal oxygen complex, air, oxygen, hydrogen peroxide, and cumene peroxide, and is more preferably a metal oxygen complex.

[0020] Preferably, the metal element in the metal oxygen complex includes a transition metal element from the fourth period.

[0021] Preferably, the transition metal element in the fourth period is selected from one or more of Co, Mn, Fe and Cr, and more preferably from one or more of Co, Mn and Cr.

[0022] Preferably, the structure of the metal oxygen-containing complex is as shown in formula (1):

[0023]

[0024] In equation (1), M is a metallic element, X is a halogen or anion; R is as shown in equation (2).

[0025]

[0026] In formula (2), R1 and R2 are each independently selected from H, C1-C10 alkyl, substituted or unsubstituted naphthyl, substituted or unsubstituted phenyl, substituted or unsubstituted benzyl; n is an integer from 0 to 6; * indicates a linking site.

[0027] Preferably, in formula (1), X is acetate, iodine or chlorine.

[0028] Preferably, in formula (2), R1 and R2 are each independently selected from H, C1-C3 alkyl, C1-C2 alkyl-substituted naphthyl, C1-C2 alkyl-substituted phenyl or benzyl; n is an integer from 0 to 3.

[0029] Preferably, the hydrogenation catalyst contains an active component and a support.

[0030] Preferably, the content of the active component is 1-40 wt% based on the total mass of the hydrogenation catalyst.

[0031] Preferably, the active component includes one or more of copper, nickel, and ruthenium.

[0032] Preferably, the conditions for the hydrogenation reaction include: a molar ratio of purified dimethyl ketone to hydrogen of 1:(1-30); and / or a space velocity of 0.1-1.5 h⁻¹ for purified dimethyl ketone. -1 ; and / or the reaction inlet temperature is 80-120℃; the reaction pressure is 2.5-6MPa.

[0033] Preferably, in step (3), the purification treatment of the crude isopropanol product includes: distilling the crude isopropanol product under reduced pressure to obtain the high-purity isopropanol.

[0034] Preferably, the conditions for vacuum distillation include:

[0035] The temperature of the column bottom is 60-74℃; the vacuum degree is 350-500mbar; the fraction collected at 45-50℃ is the high-purity isopropanol.

[0036] Compared with the prior art, the present invention has at least the following advantages:

[0037] By controlling the concentration of organic acids in the purified dimethyl ketone that undergoes hydrogenation to be less than or equal to 20 ppm, the selectivity and content of isopropanol in the isopropanol product during the hydrogenation reaction can be increased, while the content of impurities in the isopropanol product, especially ether impurities, can be reduced. Experiments have shown that if the concentration of organic acids in the purified dimethyl ketone is higher than 20 ppm, the organic acids will generate alcohols during the hydrogenation reaction, and will also promote the etherification side reaction of isopropanol, thus reducing the selectivity of isopropanol. Detailed Implementation

[0038] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0039] The first aspect of this invention provides a method for preparing high-purity isopropanol by hydrogenation of dimethyl ketone, the method comprising:

[0040] (1) Dimethyl ketone raw material is purified to obtain purified dimethyl ketone;

[0041] (2) In the presence of a hydrogenation catalyst, purified dimethyl ketone was hydrogenated with hydrogen to obtain crude isopropanol product;

[0042] (3) The crude isopropanol product is purified to obtain the high-purity isopropanol;

[0043] In step (1), the purification method includes: purifying the dimethyl ketone raw material after contacting it with an oxidant; the amount of the oxidant is 0.01-0.05 wt% of the dimethyl ketone raw material (e.g., 0.01 wt%, 0.02 wt%, 0.03 wt%, 0.04 wt%, or 0.05 wt%); the concentration of organic acid in the purified dimethyl ketone is less than or equal to 20 ppm.

[0044] In this invention, the content of organic acids is determined by gas chromatography or ion chromatography.

[0045] In this invention, the inventors discovered that by controlling the concentration of organic acids in the purified dimethyl ketone during hydrogenation to be less than or equal to 20 ppm, the selectivity and content of isopropanol in the isopropanol product during the hydrogenation reaction can be increased, while the content of impurities in the isopropanol product, especially ether impurities, can be reduced. Experiments showed that if the concentration of organic acids in the purified dimethyl ketone is higher than 20 ppm, the organic acids will generate alcohols during the hydrogenation reaction, and will also promote the etherification side reaction of isopropanol, reducing the selectivity of isopropanol. Furthermore, the inventors found that more oxidant is not necessarily better. Experimental results showed that when the oxidant content is too low, aldehyde impurities in dimethyl ketone cannot be effectively removed, while when the oxidant content is too high, the oxidant itself may introduce impurities or react with impurities in the dimethyl ketone to produce new impurities.

[0046] According to a preferred embodiment of the present invention, the concentration of organic acid in the purified dimethyl ketone is less than or equal to 2 ppm. Studies have found that the concentration of organic acid in the aforementioned embodiment can further increase the selectivity of isopropanol in the hydrogenation reaction.

[0047] In this invention, the type of organic acid is not specifically limited as long as the objective of the invention can be achieved. According to one embodiment of the invention, the organic acid contains a carboxyl group and includes, but is not limited to, one or more of formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, n-valeric acid, and isovaleric acid. In this invention, the content of organic acid refers to the total content of all organic acids in the material. The specific types of organic acids in the purified dimethyl ketone are not elaborated upon in this invention.

[0048] In this invention, the inventors discovered that reducing the concentration of organic acids in purified dimethyl ketone can increase the selectivity of isopropanol. According to one embodiment of the invention, in step (1), the purification method includes one or more of the following: distillation, fractional distillation, chemical reaction deacidification, deacidification resin, extraction, salt formation, and dehydration. That is, the dimethyl ketone obtained after contacting the dimethyl ketone raw material with an oxidant is subjected to one or more of the above purification methods in sequence.

[0049] According to a particularly preferred embodiment of the present invention, in step (1), the purification method includes distillation and dehydration. By employing the aforementioned embodiment, the purity of isopropanol in the isopropanol product can be increased, and the content of impurities such as ethers in the isopropanol product can be reduced.

[0050] In this invention, the order of distillation and dehydration is not particularly limited as long as the purpose of this invention can be achieved. According to a particularly preferred embodiment of this invention, in step (1), the purification method includes: contacting the dimethyl ketone raw material with an oxidant, followed by dehydration and distillation in sequence. By adopting the aforementioned embodiment, the content of isopropanol in the isopropanol product can be further increased, and the content of impurities such as ethers in the isopropanol product can be reduced.

[0051] In this invention, experimental results show that contacting the dimethyl ketone raw material with an oxidant, followed by sequential ketone dehydration and distillation, better increases the selectivity of isopropanol during the hydrogenation of purified dimethyl ketone. According to a preferred embodiment of this invention, the fraction collected at 54-58°C is used during distillation of the dimethyl ketone. The aforementioned embodiment can better reduce the content of impurities such as organic acids in the purified dimethyl ketone, thereby increasing the selectivity of isopropanol during the hydrogenation of purified dimethyl ketone and reducing the impurity content in the isopropanol product.

[0052] According to a particularly preferred embodiment of the present invention, the distillation conditions include: atmospheric pressure - 1 bar; and a bottom temperature of 72-76°C. Under the aforementioned distillation conditions, the impurity content in the isopropanol product can be reduced more effectively.

[0053] In this invention, the purpose of dehydration is mainly to reduce the water content in dimethyl ketone. As long as the purpose of this invention can be achieved, there is no particular limitation on the method of reducing the water content in dimethyl ketone. According to a preferred embodiment of this invention, the method of dehydrating dimethyl ketone includes: the dimethyl ketone obtained after contacting the dimethyl ketone raw material with an oxidant is fed into a dehydration tower filled with a dehydrating agent for dehydration to obtain dimethyl ketone with a water content of less than 1500 ppm.

[0054] In this invention, there are no special restrictions on the type of dehydrating agent as long as the purpose of this invention can be achieved. According to some preferred embodiments of this invention, the dehydrating agent includes one or more of molecular sieves, silica gel, activated alumina, and salts that can form crystalline hydrates.

[0055] In this invention, there are no special restrictions on the contact conditions between the dimethyl ketone raw material and the oxidant, as long as the objective of the invention can be achieved. According to a preferred embodiment of the invention, the contact conditions between the dimethyl ketone raw material and the oxidant include: atmospheric pressure and a temperature of 10-40°C. Using the aforementioned embodiment, impurities such as organic acids in dimethyl ketone can be better reduced, while the selectivity of isopropanol can be improved.

[0056] According to a preferred embodiment of the present invention, the contact conditions between the dimethyl ketone raw material and the oxidant include: a time of 0.5-10 hours, preferably 3-8 hours.

[0057] In this invention, the oxidant and dimethyl ketone are directly mixed and contacted, and the oxidant is separated or not separated depending on its state; preferably, the oxidant is not separated.

[0058] In this invention, the specific type of oxidant is not particularly limited as long as the purpose of this invention can be achieved. According to a preferred embodiment of this invention, the oxidant includes one or more of the following: metal oxygen complex, air, oxygen, hydrogen peroxide, and cumene peroxide.

[0059] According to a particularly preferred embodiment of the present invention, the oxidant is a metal oxygen-containing complex. Using the aforementioned embodiment, reducing impurities such as aldehydes in dimethyl ketones can be better reduced, while the selectivity of isopropanol is improved.

[0060] In this invention, it is understood that the metal oxygen-containing complex contains the main structure of an organic ligand and a metal element. According to a preferred embodiment of the invention, the metal element in the metal oxygen-containing complex includes a transition metal element from the fourth period.

[0061] According to a particularly preferred embodiment of the present invention, the transition metal element in the fourth period is selected from one or more of Co, Mn, Fe, and Cr, preferably one or more of Co, Mn, and Cr. Using the aforementioned embodiment, the content of reducing impurities in dimethyl ketone can be better reduced, and the content of isopropanol in the isopropanol product can be increased.

[0062] In this invention, the structure of the metal oxygen-containing complex is shown in formula (1):

[0063]

[0064] In equation (1), M is a metallic element, X is a halogen or anion; R is as shown in equation (2).

[0065]

[0066] In formula (2), R1 and R2 are each independently selected from H, C1-C10 alkyl, substituted or unsubstituted naphthyl, substituted or unsubstituted phenyl, substituted or unsubstituted benzyl; n is an integer from 0 to 6.

[0067] In this invention, the inventors discovered that using a metal oxygen-containing complex with a structure as shown in formula (1) can better reduce reducing impurities in dimethyl ketone, further increasing the selectivity and purity of isopropanol. The inventors found that the structure of the metal oxygen-containing complex of formula (1) is more stable. In particular, when formula (1) containing the main structure shown in formula (2) interacts with reducing impurities in dimethyl ketone, it can better remove reducing impurities in dimethyl ketone. When removing reducing impurities, it reduces the defects introduced by new impurities that may exist in the oxidant, thereby reducing the influence of impurities such as organic acids on the selectivity of isopropanol.

[0068] According to a particularly preferred embodiment of the present invention, in formula (1), X is acetate, iodine or chlorine.

[0069] According to a particularly preferred embodiment of the present invention, in formula (2), R1 and R2 are each independently selected from H, C1-C3 alkyl (e.g., methyl, ethyl or propyl), C1-C2 alkyl-substituted naphthyl (e.g., methylnaphthyl or ethylnaphthyl), C1-C2 alkyl-substituted phenyl (e.g., methylphenyl or ethylphenyl) or benzyl; n is an integer from 0 to 3.

[0070] In this invention, it is understood that the metal oxygen-containing complex shown in formula (1) is obtained by oxidizing the complex shown in formula (11). The conditions for the oxidation reaction are not particularly limited. For example, it can be carried out in the presence of a solvent (e.g., tetrahydrofuran). The complex with the structure of formula (11) is oxidized in the presence of oxidants such as permanganate and dichromate. The solvent is then removed after the reaction. This invention does not have any particular restrictions on this, so it will not be elaborated on in this invention.

[0071]

[0072] In equation (11), the definitions of M, X and R are the same as those in equation (1).

[0073] In this invention, it is understood that the metal oxygen complex represented by formula (11) is obtained by the coordination reaction of the organic ligand represented by formula (12) and the metal salt MX2. Those skilled in the art can select the conditions of the coordination reaction as needed. For example, the coordination reaction can be carried out in the presence of a solvent (e.g., tetrahydrofuran) and an anhydrous and oxygen-free nitrogen atmosphere. After the reaction, the solvent is removed to obtain the metal oxygen complex represented by formula (11). This invention does not have any special limitations on this, so it will not be elaborated in detail in this invention.

[0074]

[0075] In equation (11), the definition of R is the same as that in equation (1).

[0076] In this invention, the hydrogenation catalyst in step (2) can be selected as needed. Hydrogenation catalysts known in the art that can be used for the hydrogenation reaction of dimethyl ketone to prepare isopropanol are all applicable to the system of this invention. According to one embodiment of this invention, the hydrogenation catalyst contains an active component and a support.

[0077] According to a preferred embodiment of the present invention, the content of the active component is 1-40 wt% based on the total mass of the hydrogenation catalyst.

[0078] According to a preferred embodiment of the present invention, the active component includes one or more of copper, nickel, and ruthenium.

[0079] In this invention, those skilled in the art can select the conditions for the hydrogenation reaction in step (2) as needed. According to a preferred embodiment of this invention, the conditions for the hydrogenation reaction include: the molar ratio of hydrogen to purified dimethyl ketone is (1-30):1, preferably (5-10):1.

[0080] According to a preferred embodiment of the present invention, the conditions for the hydrogenation reaction include: a space velocity of 0.1-1.5 h⁻¹ for purifying the dimethyl ketone. -1 Preferably 0.5-1h -1 .

[0081] According to a preferred embodiment of the present invention, the conditions for the hydrogenation reaction include: a reaction inlet temperature of 80-120°C, preferably 90-120°C; and a reaction pressure of 2.5-6 MPa.

[0082] According to a preferred embodiment of the present invention, in step (3), the purification treatment of the crude isopropanol product includes: subjecting the crude isopropanol product to vacuum distillation to obtain the high-purity isopropanol.

[0083] According to a preferred embodiment of the present invention, the conditions for vacuum distillation include: a distillation vessel temperature of 60-74°C; a vacuum degree of 350-500 mbar; and collection of the high-purity isopropanol fraction at 45-50°C.

[0084] The present invention will be described in detail below through embodiments. In the following embodiments and comparative examples:

[0085] The mass percentage of key components in isopropanol products and the purity of isopropanol in high-purity isopropanol were obtained by gas chromatography.

[0086] The concentration of organic acids was determined by gas chromatography.

[0087] Example 1

[0088] Preparation of oxidant: In an anhydrous and oxygen-free nitrogen atmosphere, equimolar amounts of 2,2-diethyl-1,3-dioxolane-4,5-diethanol and manganese acetate were added to tetrahydrofuran solvent. The mixture was stirred at room temperature for 6 hours, and potassium permanganate (molar ratio of 1:1 to manganese acetate) was added. After reacting for 3 hours, the solvent was evaporated to obtain the oxidant after oxidation treatment.

[0089] Preparation of isopropanol:

[0090] Dimethyl ketone raw material with a purity of 99.5 wt% and an oxidant (the amount of oxidant is 0.03 wt% of the dimethyl ketone raw material) were added sequentially to a reaction vessel and mixed at 30°C and atmospheric pressure for 5 hours. The extracted dimethyl ketone was then fed into a dehydration tower packed with 4A molecular sieves for dehydration, yielding dimethyl ketone with a water content of less than 1500 ppm. The dimethyl ketone was then distilled at atmospheric pressure with a bottom temperature of 75°C, and the fraction collected at 54-58°C was used to purify the dimethyl ketone.

[0091] Purified dimethyl ketone was introduced into a dimethyl ketone hydrogenation reactor packed with 5 wt% Cu / SiO2 for hydrogenation reaction (the molar ratio of purified dimethyl ketone to hydrogen was 1:8, and the space velocity of purified dimethyl ketone was 0.8 h⁻¹). -1 The reaction was carried out at an inlet temperature of 100℃ and a reaction pressure of 6MPa to obtain crude isopropanol. The crude isopropanol was then distilled under reduced pressure at a bottom temperature of 72℃ and a vacuum of 350mbar. The fraction collected at 48-50℃ was used to obtain high-purity isopropanol.

[0092] The concentration of organic acids in dimethyl ketone used for hydrogenation, the content of isopropanol and ether compounds in crude isopropanol, and the purity of isopropanol in high-purity isopropanol are shown in Table 1.

[0093] Example 2

[0094] The method is the same as in Example 1, except that the amount of oxidant used is 0.05 wt% of the dimethyl ketone raw material.

[0095] The rest is the same as in Example 1.

[0096] The concentration of organic acids in dimethyl ketone used for hydrogenation, the content of isopropanol and ether compounds in crude isopropanol, and the purity of isopropanol in high-purity isopropanol are shown in Table 1.

[0097] Example 3

[0098] The method is the same as in Example 1, except that the amount of oxidant used is 0.01 wt% of the dimethyl ketone raw material.

[0099] The rest is the same as in Example 1.

[0100] The concentration of organic acids in dimethyl ketone used for hydrogenation, the content of isopropanol and ether compounds in crude isopropanol, and the purity of isopropanol in high-purity isopropanol are shown in Table 1.

[0101] Example 4

[0102] The method is the same as in Example 1, except that the temperature at which the isopropanol dimethyl ketone raw material comes into contact with the oxidant is 40°C.

[0103] The rest is the same as in Example 1.

[0104] The concentration of organic acids in dimethyl ketone used for hydrogenation, the content of isopropanol and ether compounds in crude isopropanol, and the purity of isopropanol in high-purity isopropanol are shown in Table 1.

[0105] Example 5

[0106] The method is the same as in Example 1, except that ferric chloride is used to replace manganese acetate in Example 1, and hydrogen peroxide is used to replace potassium permanganate in Example 1.

[0107] The rest is the same as in Example 1.

[0108] The concentration of organic acids in dimethyl ketone used for hydrogenation, the content of isopropanol and ether compounds in crude isopropanol, and the purity of isopropanol in high-purity isopropanol are shown in Table 1.

[0109] Example 6

[0110] The method is the same as in Example 1, except that:

[0111] Preparation of oxidant: In an anhydrous and oxygen-free nitrogen atmosphere, equimolar amounts of 2,2-di-tert-butyl-1,3-dioxolane-4,5-diisopropanol and manganese acetate were added to tetrahydrofuran solvent. The mixture was stirred at room temperature for 6 hours. Potassium permanganate (molar ratio of 1:1 to manganese acetate) was added and reacted for 3 hours. The solvent was then evaporated to obtain the oxidant after oxidation treatment.

[0112] The rest is the same as in Example 1.

[0113] The concentration of organic acids in dimethyl ketone used for hydrogenation, the content of isopropanol and ether compounds in crude isopropanol, and the purity of isopropanol in high-purity isopropanol are shown in Table 1.

[0114] Example 7

[0115] The method is the same as in Example 1, except that the molar ratio of purified dimethyl ketone to hydrogen is 1:4.

[0116] The rest is the same as in Example 1.

[0117] The concentration of organic acids in dimethyl ketone used for hydrogenation, the content of isopropanol and ether compounds in crude isopropanol, and the purity of isopropanol in high-purity isopropanol are shown in Table 1.

[0118] Example 8

[0119] The method is the same as in Example 1, except that the space velocity for purifying dimethyl ketone is 1.5 h⁻¹. -1 ;

[0120] The rest is the same as in Example 1.

[0121] The concentration of organic acids in dimethyl ketone used for hydrogenation, the content of isopropanol and ether compounds in crude isopropanol, and the purity of isopropanol in high-purity isopropanol are shown in Table 1.

[0122] Example 9

[0123] The method is the same as in Example 1, except that the reaction pressure is 3.5 MPa;

[0124] The rest is the same as in Example 1.

[0125] The concentration of organic acids in dimethyl ketone used for hydrogenation, the content of isopropanol and ether compounds in crude isopropanol, and the purity of isopropanol in high-purity isopropanol are shown in Table 1.

[0126] Example 10

[0127] The method is the same as in Example 1, except that the reaction inlet temperature is 80°C.

[0128] The rest is the same as in Example 1.

[0129] The concentration of organic acids in dimethyl ketone used for hydrogenation, the content of isopropanol and ether compounds in crude isopropanol, and the purity of isopropanol in high-purity isopropanol are shown in Table 1.

[0130] Comparative Example 1

[0131] The method is the same as in Example 1, except that there is no dimethyl ketone distillation operation.

[0132] The rest is the same as in Example 1.

[0133] The concentration of organic acids in dimethyl ketone used for hydrogenation, the content of isopropanol and ether compounds in crude isopropanol, and the purity of isopropanol in high-purity isopropanol are shown in Table 1.

[0134] Comparative Example 2

[0135] The method is the same as in Example 1, except that the dimethyl ketone raw material is not purified, but is used to enter the dimethyl ketone hydrogenation reactor filled with 5 wt% Cu / SiO2 for hydrogenation reaction.

[0136] The rest is the same as in Example 1.

[0137] The concentration of organic acids in dimethyl ketone used for hydrogenation, the content of isopropanol and ether compounds in crude isopropanol, and the purity of isopropanol in high-purity isopropanol are shown in Table 1.

[0138] Table 1

[0139]

[0140] As can be seen from the results in Table 1, the isopropanol prepared by Examples 1-10, which used the present invention to purify dimethyl ketone with an organic acid concentration of less than or equal to 20 ppm, has a high proportion of isopropanol.

[0141] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing high-purity isopropanol by hydrogenation of dimethyl ketone, characterized in that, The method includes: (1) Dimethyl ketone raw material is purified to obtain purified dimethyl ketone; (2) In the presence of a hydrogenation catalyst, purified dimethyl ketone was hydrogenated with hydrogen to obtain crude isopropanol product; (3) The crude isopropanol product is purified to obtain the high-purity isopropanol; In step (1), the purification method includes refining the dimethyl ketone raw material by contacting it with an oxidizing agent; the amount of the oxidizing agent is 0.01-0.05 wt% of the dimethyl ketone raw material. In step (1), the refining methods include: distillation and dehydration; Dehydration methods include: dimethyl ketone raw material is contacted with an oxidant to obtain dimethyl ketone, which is then fed into a dehydration tower filled with a dehydrating agent for dehydration to obtain dimethyl ketone with a water content of less than 1500 ppm; The fraction collected at 54-58℃ during distillation is used as the purified dimethyl ketone. The concentration of organic acids in purified dimethyl ketone is less than or equal to 20 ppm; The oxidant is a metal oxygen-containing complex; The structure of the metal oxygen-containing complex is shown in formula (1): Equation (1), In equation (1), M is a metallic element, X is a halogen or anion; R is as shown in equation (2). Equation (2), In formula (2), R1 and R2 are each independently selected from H, C1-C10 alkyl, substituted or unsubstituted naphthyl, substituted or unsubstituted phenyl, substituted or unsubstituted benzyl; n is an integer from 0 to 6; Indicates the connection site; The metal element in the metal oxygen complex is selected from transition metal elements in the fourth period.

2. The method according to claim 1, wherein, The concentration of organic acids in purified dimethyl ketone is less than or equal to 2 ppm; And / or, The organic acid contains a carboxyl group.

3. The method according to claim 2, wherein, The organic acid is selected from one or more of formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, and isovaleric acid.

4. The method according to claim 1, wherein, In step (1), the purification method includes: contacting the dimethyl ketone raw material with an oxidant, followed by dehydration and distillation.

5. The method according to claim 1, wherein, The distillation conditions include: atmospheric pressure -1 bar; and a bottom temperature of 72-76℃.

6. The method according to claim 1, wherein, The dehydrating agent is selected from one or more of molecular sieves, silica gel, activated alumina, and salts that can form crystalline hydrates.

7. The method according to claim 1, wherein, The conditions under which dimethyl ketone feedstock comes into contact with the oxidant include: Atmospheric pressure; temperature 10-40℃; and / or The time is 0.5-10 hours.

8. The method according to claim 7, wherein, The conditions under which dimethyl ketone feedstock comes into contact with the oxidant include: The temperature is 20-30℃; and / or The time is 3-8 hours.

9. The method according to claim 1, wherein, The transition metal elements in the fourth period are selected from one or more of Co, Mn, Fe, and Cr.

10. The method according to claim 9, wherein, The transition metal elements in the fourth period are one or more of Co, Mn, and Cr.

11. The method according to claim 1, wherein, In formula (1), X is acetate, iodine, or chloride; and / or In formula (2), R1 and R2 are each independently selected from H, C1-C3 alkyl, C1-C2 alkyl-substituted naphthyl, C1-C2 alkyl-substituted phenyl or benzyl; n is an integer from 0 to 3.

12. The method according to claim 1, wherein, The hydrogenation catalyst contains an active component and a support.

13. The method according to claim 12, wherein, The content of the active component is 1-40 wt% based on the total mass of the hydrogenation catalyst; and / or The active component is selected from one or more of copper, nickel, and ruthenium.

14. The method according to claim 1, wherein, The conditions for the hydrogenation reaction include: The molar ratio of purified dimethyl ketone to hydrogen is 1:(1-30); and / or The space velocity for purifying dimethyl ketone is 0.1-1.5 h⁻¹. -1 ; and / or The reaction inlet temperature is 80-120℃; the reaction pressure is 2.5-6MPa.

15. The method according to claim 1, wherein, In step (3), the purification process of the crude isopropanol product includes: distilling the crude isopropanol product under reduced pressure to obtain the high-purity isopropanol.

16. The method according to claim 15, wherein, The conditions for vacuum distillation include: The temperature of the column bottom is 60-74℃; the vacuum degree is 350-500mbar; the fraction collected at 45-50℃ is the high-purity isopropanol.

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