JP2012214441A - Method for producing oxime - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an industrially advantageous production method in the production of an oxime by an ammoximation reaction of a ketone.SOLUTION: The method for producing an oxime includes a step (1) of oxidizing cumene to give cumene hydroperoxide, a step (2) of carrying out an ammoximation reaction of a ketone, cumene hydroperoxide obtained by the step (1) and ammonia in the presence of a catalyst to give a reaction mixture containing an oxime and 2-phenyl-2-propanol, a step (3) of recovering 2-phenyl-2-propanol having ≤4.0 wt.% of an oxime from the reaction mixture obtained by the step (2), a step (4) of hydrogenating 2-phenyl-2-propanol having ≤4.0 wt.% of an oxime obtained by the step (3) in the presence of a catalyst to give cumene and a step (5) of recycling at least a part of the cumene obtained by the step (4) to the step (1).

Description

  The present invention relates to a method for producing an oxime by an ammoximation reaction of a ketone. Oxime is useful as a raw material for amides and lactams.

  As methods for producing an oxime by ammoximation reaction of a ketone, Patent Documents 1 and 2 describe a method of producing an oxime by ammoximation reaction of a ketone with cumene hydroperoxide and ammonia in the presence of a catalyst. Has been.

JP 2010-24144 A JP 2011-21006 A

  In the methods described in Patent Documents 1 and 2, 2-phenyl-2-propanol is produced as a by-product together with oxime, but a method for effectively using 2-phenyl-2-propanol produced as a by-product is desired. Therefore, an object of the present invention is to effectively utilize 2-phenyl-2-propanol as a by-product, convert 2-phenyl-2-propanol into cumene, convert the cumene into cumene hydroperoxide, and use repeatedly. An object of the present invention is to provide an industrially advantageous method for producing an oxime.

  As a result of intensive studies to solve the above problems, the present inventors have completed the present invention.

That is, this invention consists of the following structures.
[1] The following steps (1) to (5),
(1): a step of obtaining cumene hydroperoxide by oxidizing cumene;
(2): A reaction mixture containing oxime and 2-phenyl-2-propanol is obtained by subjecting cumene hydroperoxide obtained in step (1), ammonia, and a ketone to an ammoximation reaction in the presence of a catalyst. Obtaining step,
(3): recovering 2-phenyl-2-propanol having an oxime concentration of 4.0% by weight or less from the reaction mixture obtained in step (2),
(4): A step of obtaining cumene by hydrogenating 2-phenyl-2-propanol having an oxime concentration of 4.0% by weight or less obtained in step (3) in the presence of a catalyst;
(5): a step of recycling at least a part of cumene obtained in step (4) to step (1);
The manufacturing method of the oxime characterized by including.
[2] Step (4) includes the following steps (4a) and (4b),
(4a): a step of obtaining α-methylstyrene by dehydrating 2-phenyl-2-propanol having an oxime concentration of 4.0% by weight or less obtained in step (3) in the presence of a dehydration catalyst;
(4b): a step of hydrogenating the α-methylstyrene obtained in step (4a) in the presence of a hydrogenation catalyst to obtain cumene,
The production method according to [1], wherein cumene obtained in step (4b) is subjected to step (5).
[3] The production method according to [1] or [2], wherein the catalyst used in the step (2) is a catalyst containing titanium and silicon oxide.
[4] The production method according to any one of [1] to [3], wherein the ketone is a cycloalkanone.
[5] The production method according to [4], wherein the cycloalkanone is cyclohexanone.

  According to the present invention, 2-phenyl-2-propanol produced as a by-product in the ammoximation reaction of a ketone with cumene hydroperoxide and ammonia is effectively utilized to convert 2-phenyl-2-propanol into cumene, Since the cumene can be converted to cumene hydroperoxide and used repeatedly, an oxime can be produced industrially advantageously.

  Hereinafter, the present invention will be described in detail. In the present invention, as step (1), cumene is oxidized to obtain cumene hydroperoxide.

  The oxidation of cumene is usually performed by auto-oxidation by bringing cumene into contact with an oxygen-containing gas. As the oxygen source of the oxygen-containing gas, air or pure oxygen is usually used, and diluted with an inert gas as necessary. The auto-oxidation may be performed in the presence of an additive, and examples of the additive include a base. Examples of the base include alkali metal hydroxides such as sodium hydroxide and sodium hydroxide; alkali metal carbonates such as sodium carbonate and potassium carbonate; alkali metal hydrogen carbonates such as sodium hydrogen carbonate and potassium hydrogen carbonate; ammonia; Examples include ammonium carbonate. The cumene oxidation may be performed in the presence of a solvent.

  The reaction temperature in the oxidation of cumene is usually 50 to 200 ° C., and the reaction pressure is usually 0.1 to 5 MPa.

  In the present invention, as step (2), cumene hydroperoxide obtained in step (1), ammonia, and a ketone are subjected to an ammoximation reaction in the presence of a catalyst to produce oxime and 2-phenyl-2. A reaction mixture containing propanol is obtained.

  The raw material ketone used in the step (2) may be an aliphatic ketone, an alicyclic ketone, or an aromatic ketone, and two kinds thereof as required. The above may be used. Specific examples of ketones include dialkyl ketones such as acetone, ethyl methyl ketone, and isobutyl methyl ketone; alkyl alkenyl ketones such as mesityl oxide; alkyl aryl ketones such as acetophenone; diaryl ketones such as benzophenone; cyclopentanone And cycloalkanones such as cyclohexanone, cyclooctanone and cyclododecanone; cycloalkenones such as cyclopentenone and cyclohexenone. Among them, cycloalkanone is a suitable subject of the present invention.

  The raw material ketone used in the step (2) may be obtained by, for example, oxidation of alkane, or may be obtained by oxidation (dehydrogenation) of secondary alcohol, It may be obtained by hydration and oxidation (dehydrogenation) of alkenes.

  As the ammonia used in the step (2), a gaseous one may be used, a liquid one may be used, or a solution of an organic solvent may be used. When gaseous ammonia is used, it is diluted with an inert gas as necessary. Examples of the inert gas include nitrogen, carbon dioxide, helium, and argon. The amount of ammonia used is preferably adjusted so that the concentration of ammonia in the liquid phase of the reaction mixture is 1% by weight or more. Thus, by setting the ammonia concentration in the liquid phase of the reaction mixture to a predetermined value or more, the conversion rate of the raw material ketone and the selectivity of the target oxime can be increased, and as a result, the yield of the target oxime Can also be increased. The ammonia concentration is preferably 1.5% by weight or more, and usually 10% by weight or less, preferably 5% by weight or less. In addition, the standard of ammonia usage-amount is 1 mol or more normally with respect to 1 mol of ketones, Preferably it is 1.1 mol or more, More preferably, it is 1.5 mol or more.

  In the step (2), the amount of cumene hydroperoxide obtained in the step (1) is usually 0.5 to 20 mol, preferably 0.5 to 15 mol, relative to 1 mol of the ketone.

  In step (2), the ammoximation reaction is performed in the presence of a catalyst. As the catalyst used in the step (2), a catalyst containing titanium and silicon oxide is preferable. By using such a catalyst containing titanium and silicon oxide, oxime can be produced in good yield. Examples of the catalyst containing titanium and silicon oxide include silicate containing titanium, silica containing titanium, and the like.

  Examples of the silicate containing titanium include mesoporous silicate containing titanium, crystalline silicate containing titanium, and the like. Examples of the mesoporous silicate include MCM-41, MCM-48, HMS, SBA-15, FSM-16, MSU-H, MSU-F and the like. Examples of the crystalline silicate include silicalite-1 (MFI type), silicalite-2 (MEL type), ITQ-1 (MWW type), YNU-2 (MSE type), and the like. Among silicates containing titanium, mesoporous silicates containing titanium are preferable, MCM-41 containing titanium, and HMS containing titanium are more preferable (hereinafter referred to as MCM-41 containing titanium and HMS containing titanium). These may be referred to as Ti-MCM-41 and Ti-HMS, respectively). The mesoporous silicate means a mesoporous silicate having a pore diameter of about 2 to 50 nm. The presence or absence of a mesoporous structure can be confirmed by the presence or absence of a peak at 2θ = 0.2 to 4.0 ° in XRD (X-ray diffraction) measurement using copper Kα rays. Titanium in the silicate containing titanium may be incorporated into the silicate skeleton, may be incorporated into the pores, or may be supported on the surface of the silicate skeleton. In the silicate containing titanium, the mesoporous silicate containing titanium, the crystalline silicate containing titanium, the MCM-41 containing titanium, and the HMS containing titanium, each contains titanium in the silicate skeleton. Is preferred.

  Examples of the silica containing titanium include those in which titanium is supported on a silica carrier, titania-silica composite oxide, and the like.

  Examples of elements other than titanium, silicon, and oxygen that can be included in the catalyst containing titanium and silicon oxide include boron, aluminum, gallium, iron, and chromium. When the catalyst is a silicate containing titanium, elements other than titanium, silicon and oxygen may be incorporated into the silicate skeleton, may be incorporated into the pores, and may be incorporated into the surface of the silicate skeleton. It may be supported. When the catalyst is a silicate containing titanium in a silicate skeleton (titanosilicate), the silicate contains titanium, silicon and oxygen as elements constituting the skeleton, and substantially includes titanium, silicon and oxygen. The skeleton may be composed of only the skeleton, and the element forming the skeleton may further contain elements other than titanium, silicon, and oxygen, such as boron, aluminum, gallium, iron, and chromium. When the catalyst is titanium-containing silica, elements that can be contained in addition to titanium, silicon, and oxygen may be incorporated in the silica skeleton or may be supported on the silica surface.

  The titanium content in the catalyst containing titanium and silicon oxide is usually 0.0001 or more, preferably 0.005 or more, and usually 1.5 or more, expressed as an atomic ratio (Ti / Si) to silicon. Hereinafter, it is preferably 1.0 or less. When the catalyst containing titanium and silicon oxide contains an element other than titanium, silicon and oxygen, the content of the element is usually 1.0 or less, preferably 0.5 in terms of atomic ratio relative to silicon. It is as follows. Oxygen can be present corresponding to the content and oxidation number of each element other than oxygen. A typical composition of such a catalyst containing titanium and silicon oxide can be represented by the following formula with silicon as the reference (= 1).

SiO ₂ · xTiO ₂ · yM ⁿ O _{n / 2}

(In the formula, M represents at least one element other than silicon, titanium and oxygen, n is the oxidation number of the element, x is 0.0001 to 1.0, and y is 0 to 1.0. .)

  In the above formula, M is an element other than titanium, silicon, and oxygen, and examples thereof include boron, aluminum, gallium, iron, and chromium.

  The catalyst containing titanium and silicon oxide is prepared by a known hydrothermal synthesis method, sol-gel method, or the like. The catalyst containing titanium and silicon oxide may be contact-treated with a silicon compound. Examples of such silicon compounds include organic silicon compounds and inorganic silicon compounds, and among them, organic silicon compounds are preferable.

  The catalyst used in step (2) may be used after being formed into a granular shape or a pellet shape, or may be used by being supported on a carrier. When molding, a binder may be used as necessary.

  In the ammoximation reaction of step (2), a solvent may be used. Examples of solvents include hydrocarbons such as butane, pentane, hexane, cyclohexane, benzene, cumene, toluene, xylene, acetonitrile, propionitrile, butyronitrile, isobutyronitrile, trimethylacetonitrile, valeronitrile, Nitriles such as isovaleronitrile and benzonitrile, alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, s-butyl alcohol, t-butyl alcohol, and t-amyl alcohol And two or more of them can be used as necessary. In addition, when the cumene hydroperoxide obtained at a process (1) is a mixture with a solvent, this solvent can be used as a solvent of a process (2).

  When using a solvent, the quantity is 1-500 weight part normally with respect to 1 weight part of ketone, Preferably it is 2-300 weight part.

  The ammoximation reaction in step (2) may be performed in a batch system, a semi-batch system, a continuous system, or a combination of a batch system, a semi-batch system and a continuous system. Also good. Among these, a semi-batch type, a continuous type or a combination thereof is preferable. In the case of a semi-batch type, it is preferable to carry out the reaction while supplying the reaction raw material into a stirring / mixing type or loop type reactor. In the case of a continuous type, a method of extracting the liquid phase of the reaction mixture while supplying the reaction raw material into a stirring / mixing type or loop type reactor, or a fixed bed flow for circulating the reaction raw material in a fixed bed reactor filled with a catalyst. It is desirable to carry out the above reaction in terms of productivity and operability.

  In the semi-batch type reaction using the stirring and mixing type reactor, for example, a reaction mixture in which a catalyst is suspended is present in the reactor, and a reaction raw material such as a ketone is supplied into the reaction mixture. It can be suitably performed. The continuous reaction using a stirring and mixing reactor is, for example, a reaction mixture in which a reaction mixture in which a catalyst is suspended is present in the reactor and a reaction raw material such as a ketone is supplied to the reactor. It can carry out suitably by extracting the liquid phase of the reaction mixture from the filter through a filter.

  In the semi-batch or continuous reaction using the stirring and mixing reactor, ketone and ammonia are preferably supplied into a reactor in which a solvent, a catalyst, and cumene hydroperoxide are previously added. More preferably, ketone, cumene hydroperoxide and ammonia are fed into a reactor containing cumene hydroperoxide and ammonia. Specifically, first, a solvent, a catalyst, and cumene hydroperoxide are introduced into a stirring and mixing reactor. There is no particular restriction on the order of introduction. After these are introduced into the reactor, the catalyst is suspended by stirring, and then ketone and ammonia are fed. The ketone and ammonia may be supplied alone (so-called co-feed) or a mixture thereof. In addition, ammonia may be put in the reactor together with the solvent, catalyst and cumene hydroperoxide in advance, and then the ketone and additional ammonia may be supplied into the reactor, or the solvent, catalyst and cumene hydroperoxide may be reacted in advance. Then, cumene hydroperoxide may be additionally supplied together with ketone and ammonia, or ammonia together with a solvent, catalyst and cumene hydroperoxide is previously placed in the reactor, and then ketone and ammonia are added. Additional cumene hydroperoxide may be fed along with additional ammonia. The ketone, ammonia and cumene hydroperoxide used for the supply may be diluted with a solvent.

  The amount of the catalyst used for the semi-batch or continuous reaction using the stirring and mixing reactor may be about 0.1 to 20% by weight with respect to the total amount of the reaction mixture. For the purpose of suppressing the decrease in the catalyst activity, for example, as disclosed in JP-A-2004-83560, a silicon compound such as silica or silicic acid may coexist in the reaction system.

  In a semi-batch or continuous reaction using a stirring and mixing reactor, when cumene hydroperoxide is put in the reactor in advance, the amount of cumene hydroperoxide to be put in advance depends on the amount of liquid in the mixture in the reactor. The concentration of cumene hydroperoxide in the phase is adjusted to 0.01 to 50% by weight. In addition, in a semi-batch or continuous reaction using a stirring and mixing reactor, when ammonia is put in the reactor in advance, the amount of ammonia to be put in advance is the liquid phase in the mixture in the reactor. The ammonia concentration is adjusted to 0.1 to 15% by weight.

  The amount of cumene hydroperoxide fed in a semi-batch or continuous reaction using a stirring and mixing reactor is usually 0.5 to 20 moles, preferably 0.5 to 15 moles per mole of ketone. Is a mole.

  In the semi-batch or continuous reaction using the stirring and mixing reactor, the amount of ammonia supplied is usually 1 mol or more per 1 mol of the ketone.

  In addition, from the viewpoint of preventing the decomposition of cumene hydroperoxide, the stirring and mixing type reactor is preferably a glass-lined one or a stainless steel one.

  The reaction in the fixed bed flow system is, for example, passing ketone, cumene hydroperoxide and ammonia as reaction raw materials into a fixed bed reactor filled with a catalyst, together with a solvent as necessary, by upflow or downflow. By doing so, the reaction can be carried out. When gaseous ammonia is used as ammonia, the gaseous ammonia is diluted with an inert gas as necessary, and the supply direction thereof is parallel or countercurrent to the supply direction of raw materials other than ammonia. Either of these may be used. The reaction is preferably carried out under pressurized conditions. The contact time between the catalyst and the reaction raw material can be adjusted by controlling the pressurizing condition.

  As the fixed bed reactor, various flow-type fixed bed reactors in which a raw material supply port and a reaction liquid outlet port are provided in the reactor can be used. The number of reaction tubes is not particularly limited, and either a single tube fixed bed reactor or a multi-tube fixed bed reactor can be used. Moreover, a fixed bed reactor of an adiabatic system or a heat exchange system can be used. From the viewpoint of preventing the decomposition of cumene hydroperoxide, glass-lined or stainless steel is preferred.

  The reaction temperature of the ammoximation reaction is usually 50 to 200 ° C, preferably 80 to 150 ° C. The reaction pressure is usually 0.1 to 5.0 MPa in absolute pressure, preferably 0.2 to 1.0 MPa. In order to make ammonia easily dissolve in the liquid phase of the reaction mixture, the reaction is preferably performed under pressure. In this case, the pressure may be adjusted using an inert gas such as nitrogen or helium.

  In the present invention, as the step (3), the oxime concentration is 4.0% by weight or less from the reaction mixture containing the oxime obtained by the ammoximation reaction of the step (2) and 2-phenyl-2-propanol. 2-Phenyl-2-propanol is recovered. By subjecting 2-phenyl-2-propanol having an oxime concentration of 4.0% by weight or less obtained in step (3) to hydrogenation in step (4), hydrogenation in step (4) is efficiently performed. It can be carried out. In step (3), the oxime concentration in the recovered 2-phenyl-2-propanol is 4.0% by weight or less, preferably 3.5% by weight or less.

  In the step (3), for example, after the catalyst is separated from the reaction mixture by filtration or decantation, the oxime concentration in the recovered 2-phenyl-2-propanol is 4.0% by weight or less. The method for separating oxime and 2-phenyl-2-propanol by distilling the liquid phase so that the oxime concentration in the recovered 2-phenyl-2-propanol is 4.0% by weight or less, The oxime and 2-phenyl-2-propanol are separated by extracting 2-phenyl-2-propanol from the liquid phase so that the oxime concentration in 2-phenyl-2-propanol is 4.0% by weight or less. Method: Crystallizing oxime from the liquid phase results in an oxime concentration in 2-phenyl-2-propanol of 4.0% by weight or less. The oxime concentration in 2-phenyl-2-propanol can be increased by treating the liquid phase by combining two or more methods of separating oxime and 2-phenyl-2-propanol, distillation, extraction and crystallization. Examples include a method of separating oxime and 2-phenyl-2-propanol so as to be 4.0% by weight or less. The separated catalyst can be reused after being subjected to treatments such as washing, calcination, and recontact with a silicon compound as necessary. In addition, when the reaction mixture contains a solvent, unreacted ketone, or unreacted ammonia, the solvent recovered by distillation of the liquid phase, unreacted ketone, or unreacted ammonia is used in the step ( It can be reused in 2). The obtained oxime is suitably used as a raw material for producing the corresponding amide compound by Beckmann rearrangement reaction.

  In the present invention, as step (4), 2-phenyl-2-propanol having an oxime concentration of 4.0% by weight or less obtained in step (3) is hydrogenated in the presence of a catalyst. Get. The method of hydrogenating 2-phenyl-2-propanol to obtain cumene includes (A) a method of hydrogenolysis of 2-phenyl-2-propanol, and (B) after dehydrating 2-phenyl-2-propanol. The method (B) is preferred from the viewpoint of the yield of cumene obtained and the catalyst life.

  When 2-phenyl-2-propanol is hydrocracked, the hydrocracking reaction is performed by contacting 2-phenyl-2-propanol with hydrogen in the presence of a catalyst. A solvent may be used in the hydrogenolysis reaction. When 2-phenyl-2-propanol having an oxime concentration of 4.0% by weight or less obtained in the step (3) is a mixture with a solvent, the solvent may be used as the solvent in the step (4). Good. The hydrocracking reaction is carried out under liquid phase reaction conditions or gas phase reaction conditions.

  In the case of hydrogenation after dehydration of 2-phenyl-2-propanol, the step (4) is performed by adding 2-phenyl-2-propanol having an oxime concentration of 4.0% by weight or less obtained in the step (3). The step (4a) of obtaining α-methylstyrene by dehydration in the presence of a dehydration catalyst and the α-methylstyrene obtained in step (4a) are hydrogenated in the presence of a hydrogenation catalyst to form cumene. And obtaining step (4b). Examples of the dehydration catalyst used in the step (4a) include inorganic acids such as sulfuric acid and phosphoric acid, organic acids such as methanesulfonic acid and p-toluenesulfonic acid, activated alumina, titania, zirconia, silica alumina, Solid acids such as zeolite and the like can be mentioned. Among them, solid acids are preferable from the viewpoint of selectivity of the obtained α-methylstyrene, ease of separation after the reaction, and catalyst life, and among the solid acids, active alumina is preferable. preferable.

  The dehydration reaction is performed by contacting 2-phenyl-2-propanol with a dehydration catalyst. In the dehydration reaction, a solvent may be used. When 2-phenyl-2-propanol having an oxime concentration of 4.0% by weight or less obtained in the step (3) is a mixture with a solvent, the solvent may be used as the solvent in the step (4a). Good. The reaction temperature in the dehydration reaction is usually 50 to 450 ° C., preferably 150 to 300 ° C., and the reaction pressure is usually 0.01 to 10 MPa. In the step (4a), hydrogen used in the step (4b) may be present in advance, and α-methylstyrene and hydrogen may be provided to the step (4b). Further, the α-methylstyrene obtained contains water produced by the dehydration reaction, but it may be used for the step (4b) as it is, or may be used for the step (4b) after separating the water.

  Examples of the hydrogenation catalyst used in the step (4b) include a catalyst containing a metal or a metal compound such as nickel, palladium, platinum, or copper. Among them, the suppression of the nuclear hydrogenation reaction of α-methylstyrene is obtained. From the viewpoint of the selectivity of cumene to be produced, a catalyst containing palladium or a compound thereof, or a catalyst containing copper or a compound thereof is preferable. Examples of the catalyst containing palladium or a compound thereof include a palladium-supported catalyst in which palladium is supported on a carrier, and examples of the catalyst including copper or a compound thereof include a copper-supported catalyst in which copper is supported on a carrier. It is done. Examples of the carrier include alumina, silica, titania, magnesia, activated carbon and the like. You may use 2 or more types of hydrogenation catalysts as needed.

  The hydrogenation reaction is carried out by contacting α-methylstyrene and hydrogen in the presence of a hydrogenation catalyst. In the hydrogenation reaction, a solvent may be used. In addition, when (alpha) -methylstyrene obtained at a process (4a) is a mixture with a solvent, you may use this solvent as a solvent of a process (4b). The reaction temperature in the hydrogenation reaction is usually 0 to 500 ° C., preferably 30 to 300 ° C., and the reaction pressure is usually 0.1 to 10 MPa. The hydrogen used in the hydrogenation reaction is usually 1 to 10 mol, preferably 1 to 5 mol, relative to 1 mol of α-methylstyrene. When a dehydration / hydrogenation catalyst that acts as a catalyst for both the dehydration reaction and the hydrogenation reaction is used, the steps (4a) and (4b) can be performed in one step.

  The dehydration reaction in the step (4a) and the hydrogenation reaction in the step (4b) may be performed in a batch system, a semi-batch system, a continuous system, a batch system, a semi-batch system, and You may carry out by the combination of a continuous type. Among these, the continuous type is preferable. In the case of a continuous system, it is desirable from the viewpoint of productivity and operability that the reaction is carried out in a fixed bed flow system in which the reaction raw material is passed through a fixed bed reactor filled with a catalyst. The reaction in the fixed bed flow system can be carried out, for example, by supplying the reaction raw material together with a solvent, if necessary, in an up flow, down flow or trickle flow into a fixed bed reactor filled with a catalyst. The dehydration reaction and the hydrogenation reaction may each be performed using a single fixed bed reactor, or may be performed using the same fixed bed reactor.

  In the present invention, as step (5), at least a part of cumene obtained in step (4) is recycled to step (1). In steps (1) to (5), 2-phenyl-2-propanol produced as a by-product in the ammoximation reaction is effectively used to convert 2-phenyl-2-propanol into cumene, and the cumene is converted to cumene. It can be repeatedly used after being converted to hydroperoxide.

  Hereinafter, although the experiment example of this invention is shown, this invention is not limited by these. The analysis of 2-phenyl-2-propanol and cumene in the reaction solution was performed by gas chromatography, and the conversion rate of 2-phenyl-2-propanol and the selectivity and yield of cumene were calculated from the analysis results. .

Experimental example 1
In a 1 L autoclave (reactor), 10.29 g of 2-phenyl-2-propanol containing 89% by weight of cyclohexanone oxime, 89.74 g of toluene, and 3.0 g of a palladium / alumina catalyst were placed. After replacing the gas phase in the reactor with nitrogen, the pressure was increased to 0.8 MPa (gauge pressure) with hydrogen gas, and the temperature was raised to 200 ° C. with stirring. After completion of the temperature rise, the reaction was continued for 6 hours, and the extracted reaction solution was analyzed by gas chromatography. The conversion of 2-phenyl-2-propanol was 99.6% and the selectivity for cumene was 88. The yield of cumene was 58.1%.

Experimental example 2
In a 1 L autoclave (reactor), 10.50 g of 2-phenyl-2-propanol containing 89% by weight of cyclohexanone oxime, 89.50 g of toluene, and 3.0 g of a palladium / alumina catalyst were added. After replacing the gas phase in the reactor with nitrogen, the pressure was increased to 0.8 MPa (gauge pressure) with hydrogen gas, and the temperature was raised to 200 ° C. with stirring. After completion of the temperature rise, the reaction was continued for 6 hours, and the extracted reaction solution was analyzed by gas chromatography. The conversion of 2-phenyl-2-propanol was 19.3% and the selectivity for cumene was 79. The yield of cumene was 0% and 15.2%.

Claims (5)

The following steps (1) to (5),
(1): a step of obtaining cumene hydroperoxide by oxidizing cumene;
(2): A reaction mixture containing oxime and 2-phenyl-2-propanol is obtained by subjecting cumene hydroperoxide obtained in step (1), ammonia, and a ketone to an ammoximation reaction in the presence of a catalyst. Obtaining step,
(3): recovering 2-phenyl-2-propanol having an oxime concentration of 4.0% by weight or less from the reaction mixture obtained in step (2),
(4): A step of obtaining cumene by hydrogenating 2-phenyl-2-propanol having an oxime concentration of 4.0% by weight or less obtained in step (3) in the presence of a catalyst;
(5): a step of recycling at least a part of cumene obtained in step (4) to step (1);
The manufacturing method of the oxime characterized by including. Step (4) includes the following steps (4a) and (4b),
(4a): a step of obtaining α-methylstyrene by dehydrating 2-phenyl-2-propanol having an oxime concentration of 4.0% by weight or less obtained in step (3) in the presence of a dehydration catalyst;
(4b): a step of hydrogenating the α-methylstyrene obtained in step (4a) in the presence of a hydrogenation catalyst to obtain cumene,
The manufacturing method of Claim 1 which attaches | subjects the cumene obtained by the process (4b) to a process (5).   The production method according to claim 1 or 2, wherein the catalyst used in step (2) is a catalyst containing titanium and silicon oxide.   The production method according to claim 1, wherein the ketone is a cycloalkanone.   The production method according to claim 4, wherein the cycloalkanone is cyclohexanone.