JP2015174826A - Method of producing methacrylate ester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an efficient method of producing methacrylate esters.SOLUTION: A method of producing a methacrylate ester comprises reacting a compound having a hydroxyl group and carbon monoxide with methylacetylene in the presence of a catalyst containing a group 10 metal compound, a protonic acid and a phosphine compound and is characterized by reducing the partial pressure of carbon monoxide in the course of the reaction. The partial pressure of carbon monoxide is preferably reduced by 0.1 MPa or more, and the partial pressure of carbon monoxide at the beginning of the reduction of carbon monoxide is preferably 1.0 MPa or higher.

Description

  The present invention relates to a method for producing a methacrylic acid ester.

  As a method for producing a methacrylate ester by reacting a compound having a hydroxyl group and carbon monoxide with methylacetylene in the presence of a catalyst containing a Group 10 metal compound, a protonic acid and a phosphine compound, for example, Patent Document 1 discloses , A method of producing methyl methacrylate by reacting methylacetylene with methanol and carbon monoxide under a constant partial pressure of carbon monoxide using a palladium compound, a protonic acid and a phosphine compound as a catalyst. .

JP 2010-120921 A

  However, the above conventional methods are not always satisfactory in terms of productivity per Group 10 metal in the production of methacrylic acid esters.

  Then, the objective of this invention is providing the method of manufacturing a methacrylic ester efficiently.

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

That is, this invention consists of the following structures.
[1] A method for producing a methacrylic acid ester in which a compound having a hydroxyl group and carbon monoxide are reacted with methylacetylene in the presence of a catalyst containing a Group 10 metal compound, a protonic acid and a phosphine compound. A method for producing a methacrylic acid ester, wherein the partial pressure of carbon oxide is lowered.
[2] The production method according to [1], wherein the partial pressure of carbon monoxide is reduced by 0.1 MPa or more.
[3] The production method according to [1] or [2], wherein the partial pressure of carbon monoxide at the time of starting to lower the partial pressure of carbon monoxide is 1.0 MPa or more.
[4] The production method according to any one of [1] to [3], wherein the conversion of methylacetylene is within the range of 1 to 70% when the partial pressure of carbon monoxide starts to be lowered.
[5] The production method according to any one of [1] to [4], wherein the reaction pressure is lowered during the reaction and the partial pressure of carbon monoxide is lowered.
[6] The production method according to any one of [1] to [5], wherein the reaction time at the start of lowering the partial pressure of carbon monoxide is 1 to 300 minutes.
[7] The production method according to any one of [1] to [6], wherein the catalyst further contains an amine compound.
[8] The production method according to any one of [1] to [7], wherein the Group 10 metal compound is a palladium compound.
[9] The production method according to any one of [1] to [8], wherein the phosphine compound is an aromatic tertiary pyridylphosphine.
[10] The production method according to any one of [1] to [9], wherein the protonic acid is a sulfonic acid compound.
[11] The production method according to any one of [7] to [10], wherein the amine compound is N, N-dimethylaniline.
[12] The production method according to any one of [1] to [11], wherein the reaction is performed in a continuous manner using n reaction vessels (n represents an integer of 2 or more) connected in series. .
[13] The carbon monoxide partial pressure in the n-th reaction tank located at the most downstream side in the flow direction of methylacetylene is lower than the partial pressure of carbon monoxide in the first reaction tank located at the most upstream position. ] The manufacturing method of description.
[14] The production method according to [13], wherein the reaction pressure in the n-th reaction tank located on the most downstream side in the flow direction of methylacetylene is lower than the reaction pressure in the first reaction tank located on the most upstream side.

  According to the present invention, a methacrylic acid ester can be produced efficiently.

  In the present invention, a compound having a hydroxyl group and carbon monoxide are reacted with methylacetylene in the presence of a catalyst containing a Group 10 metal compound, a protonic acid and a phosphine compound.

  The methylacetylene used in the method of the present invention preferably has a propadiene content of 50 ppm by weight or less, more preferably 30 ppm by weight or less, still more preferably 20 ppm by weight or less, even more preferably 10 ppm by weight or less, Particularly preferred is 5 ppm by weight or less. Methylacetylene may contain impurities in addition to propadiene as long as it does not significantly inhibit the reaction. Specific examples of such impurities include butadiene, propylene, butene, propane, carbon monoxide, and carbon dioxide. The carbon monoxide used for the reaction in the method of the present invention may contain pure carbon monoxide, a catalyst such as nitrogen, helium, carbon dioxide and argon, or a gas inert to methylacetylene.

  The reaction of the present invention is carried out using a catalyst containing a Group 10 metal compound, a phosphine compound and a protonic acid. The catalyst is preferably used as a mixture containing a Group 10 metal compound, a protonic acid and a phosphine compound. The amount of the Group 10 metal compound, protonic acid and phosphine compound used may be a catalytic amount, but is typically used in the manner exemplified below.

  Examples of the Group 10 metal compound include nickel compounds, palladium compounds, and platinum compounds, and preferably include palladium compounds. Such palladium compounds include palladium acetylacetonate, tetrakis (triphenylphosphine) palladium, bis (triphenylphosphine) palladium acetate, palladium acetate, palladium trifluoroacetate, palladium trifluoromethanesulfonate, palladium sulfate, palladium chloride and these Mention may be made of mixtures. More preferably, the palladium compound is palladium acetylacetonate, tetrakis (triphenylphosphine) palladium, bis (triphenylphosphine) palladium acetate, palladium acetate, palladium trifluoroacetate, palladium trifluoromethanesulfonate, palladium sulfate and mixtures thereof. More preferably, it is palladium acetate. It is preferable that the usage-amount of a group 10 metal compound is 1/200000 mol or less with respect to 1 mol of methyl acetylene, More preferably, it is the range of 1/100000 to 1/200000 mol. That is, the amount of methylacetylene used is preferably 200,000 mol or more, more preferably in the range of 200,000 to 1,000,000 mol with respect to 1 mol of the Group 10 metal compound.

  The phosphine compound is not particularly limited, but usually a tertiary phosphine compound is used, preferably the following formula (1)

（式（１）中、Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５、Ｒ^６、Ｒ^７、Ｒ^８及びＲ^９は、それぞれ独立に、水素原子、ハロゲン原子、シアノ基、水酸基、ハロゲン原子で置換されていてもよいアルキル基、アラルキル基、置換又は無置換アリール基、ピリジル基、シリル基、アミノ基、アルコキシ基、アラルキルオキシ基、アリールオキシ基及びアシル基からなる群から選ばれる置換基を表し、それぞれ隣接する基は互いに結合して環を形成していてもよい。ｎは０〜３の整数を表す。）
で表される芳香族第３級ホスフィン化合物が用いられる。

(In the formula (1), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ are each independently a hydrogen atom, a halogen atom, a cyano group, a hydroxyl group, Selected from the group consisting of an alkyl group optionally substituted with a halogen atom, an aralkyl group, a substituted or unsubstituted aryl group, a pyridyl group, a silyl group, an amino group, an alkoxy group, an aralkyloxy group, an aryloxy group, and an acyl group Represents a substituent, and groups adjacent to each other may be bonded to each other to form a ring, and n represents an integer of 0 to 3.)
The aromatic tertiary phosphine compound represented by these is used.

  Among the aromatic tertiary phosphine compounds represented by the above formula (1), aromatic tertiary pyridylphosphine in which n is an integer of 1 to 3 is more preferable. Specific examples of the aromatic tertiary pyridylphosphine include diphenyl-2-pyridylphosphine, diphenyl (6-methyl-2-pyridyl) phosphine, diphenyl (6-ethyl-2-pyridyl) phosphine, diphenyl [6- ( n-propyl) -2-pyridyl] phosphine, diphenyl [6- (iso-propyl) -2-pyridyl] phosphine, diphenyl [6- (n-butyl) -2-pyridyl] phosphine, diphenyl [6- (iso- Butyl) -2-pyridyl] phosphine, diphenyl (6-phenyl-2-pyridyl) phosphine, diphenyl (6-hydroxy-2-pyridyl) phosphine, diphenyl (6-methoxy-2-pyridyl) phosphine, diphenyl (6-fluoro) -2-pyridyl) phosphine, diphenyl (6-chloro-2) Pyridyl) phosphine, diphenyl (6-bromo-2-pyridyl) phosphine, bis (4-fluorophenyl) (2-pyridyl) phosphine, bis (4-chlorophenyl) (2-pyridyl) phosphine, bis (4-bromophenyl) (2-pyridyl) phosphine, bis (3-methylphenyl) (2-pyridyl) phosphine, bis (4-methylphenyl) (2-pyridyl) phosphine, bis (4-methoxyphenyl) (2-pyridyl) phosphine, bis [4- (Trifluoromethyl) phenyl] (2-pyridyl) phosphine, bis (3,4,5-trifluorophenyl) (2-pyridyl) phosphine, bis (4-fluorophenyl) (6-methyl-2- Pyridyl) phosphine, bis (4-chlorophenyl) (6-methyl-2-pyridyl) phos Bis (4-bromophenyl) (6-methyl-2-pyridyl) phosphine, bis (3-methylphenyl) (6-methyl-2-pyridyl) phosphine, bis (4-methylphenyl) (6-methyl) -2-pyridyl) phosphine, bis (4-methoxyphenyl) (6-methyl-2-pyridyl) phosphine, bis [4- (trifluoromethyl) phenyl] (6-methyl-2-pyridyl) phosphine, bis (4 -Methylphenyl) (6-ethyl-2-pyridyl) phosphine, bis (4-methylphenyl) [6- (n-propyl) -2-pyridyl] phosphine, bis (4-methylphenyl) [6- (iso- Propyl) -2-pyridyl] phosphine, bis (4-methylphenyl) [6- (n-butyl) -2-pyridyl] phosphine, bis (4-methyl) Phenyl) [6- (iso-butyl) -2-pyridyl] phosphine, bis (4-methoxyphenyl) (6-ethyl-2-pyridyl) phosphine, bis (4-methoxyphenyl) [6- (n-propyl) -2-pyridyl] phosphine, bis (4-methoxyphenyl) [6- (iso-propyl) -2-pyridyl] phosphine, bis (4-methoxyphenyl) [6- (n-butyl) -2-pyridyl] phosphine Bis (4-methoxyphenyl) [6- (iso-butyl) -2-pyridyl] phosphine, bis (2-pyridyl) phenylphosphine, tris (2-pyridyl) phosphine, bis (6-methyl-2-pyridyl) Phenylphosphine, tris (6-methyl-2-pyridyl) phosphine, bis (3,5-dimethylphenyl) (2-pyridylphospho) Fin), bis (3,5-dimethylphenyl) (6-methyl-2-pyridylphosphine), bis (3,5-dimethylphenyl) (6-ethyl-2-pyridylphosphine), bis (3,5-dimethyl) -4-methoxyphenyl) (2-pyridylphosphine), bis (3,5-dimethyl-4-methoxyphenyl) (6-methyl-2-pyridylphosphine), bis (3,5-dimethyl-4-methoxyphenyl) (6-ethyl-2-pyridylphosphine) is exemplified, and diphenyl-2-pyridylphosphine, diphenyl (6-methyl-2-pyridyl) phosphine, bis (3,5-dimethylphenyl) (2- Pyridylphosphine), bis (3,5-dimethylphenyl) (6-methyl-2-pyridylphosphine), bis (3,5-di-) Chill-4-methoxyphenyl) (2-pyridyl) phosphine, bis (3,5-dimethyl-4-methoxyphenyl) (6-methyl-2-pyridyl phosphine) are exemplified.

  These aromatic tertiary pyridylphosphines are not limited to being used alone, and may be used by appropriately mixing them.

  The amount of the phosphine compound used is preferably 2 to 300 mol, more preferably 5 to 240 mol, per 1 mol of the Group 10 metal compound. The amount of the phosphine compound used per 1 mol of methylacetylene is preferably 0.000020 mol or more, more preferably 0.000020 to 0.00048 mol, and the amount of the phosphine compound used per mol of propadiene is 2 mol or more. Is preferred.

  The above aromatic tertiary pyridylphosphine can be produced by a known method. For example, as disclosed in JP-A-2-277551, various aromatic tertiary pyridylphosphines are produced by reacting a halogenated pyridine with an alkyllithium to lithiate and then reacting with a phosphine chloride. I can do it.

  Moreover, a preferable result is obtained also when a monodentate tertiary monophosphine compound is allowed to coexist with the aromatic tertiary pyridylphosphine. The monodentate tertiary monophosphine compound in this case is a tertiary phosphine compound that does not contain a functional group that becomes a coordination site in addition to one phosphorus atom. The monodentate tertiary monophosphine compound is a trialkylphosphine, or the same or different aryl which may be substituted with at least one substituent selected from the group consisting of an alkyl group, a halogen atom, a haloalkyl group and an alkoxy group. An aromatic tertiary phosphine having a group is exemplified. Specific examples of the monodentate tertiary monophosphine compound include triethylphosphine, tributylphosphine, tricyclohexylphosphine, triphenylphosphine, tris (4-fluorophenyl) phosphine, tris (4-chlorophenyl) phosphine, tris (4- Methylphenyl) phosphine, tris [4- (trifluoromethyl) phenyl] phosphine, tris (4-methoxyphenyl) phosphine, tris (3-methylphenyl) phosphine, tris [3,5-bis (trifluoromethyl) phenyl] Examples include phosphine, (4-methylphenyl) (diphenyl) phosphine, and mixtures thereof, preferably the above-mentioned aromatic tertiary phosphine, more preferably triphenylphosphine. Although there is no restriction | limiting in particular in the usage-amount, Preferably it is the range of 1-600 mol with respect to 1 mol of group 10 metal compounds, More preferably, it is the range of 1-300 mol.

  Examples of the protonic acid include organic or inorganic protonic acids. Specific examples of the protonic acid include boric acid, orthophosphoric acid, pyrophosphoric acid, sulfuric acid, hydrohalic acid, benzenephosphoric acid, benzenesulfonic acid, p-toluenesulfonic acid, naphthalenesulfonic acid, chlorosulfonic acid, and methanesulfonic acid. , Trifluoromethanesulfonic acid, trimethylmethanesulfonic acid, monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, trifluoroacetic acid, oxalic acid, bis (trifluoromethanesulfonyl) imide, tris (trifluoromethanesulfonyl) methide and mixtures thereof, Preferably, sulfonic acid compounds such as benzenesulfonic acid, p-toluenesulfonic acid, naphthalenesulfonic acid, chlorosulfonic acid, methanesulfonic acid, trifluoromethanesulfonic acid, trimethylmethanesulfonic acid, more preferably Tan sulfonic acid is used. Although the usage-amount is not specifically limited, Preferably it is 3-300 mol with respect to 1 mol of group 10 metal compounds, More preferably, it is 10-240 mol.

  In the reaction, the use of an amine compound as a catalyst is not essential, but the reaction in the presence of an amine compound may give a favorable result. The amine compound is not particularly limited, but a known tertiary amine or cyclic amine is usually used. Specific examples of the amine compound include N, N-dialkylaniline, pyridine, quinoline, isoquinoline, triazine, imidazole, triethylamine, tributylamine, N, N-diisopropylethylamine, and mixtures thereof, preferably N, N -Dimethylaniline, pyridine. Although there is no restriction | limiting in the addition amount of an amine compound, Preferably it is 1-50 mol with respect to 1 mol of proton acids, More preferably, it is the range of 1-10 mol.

  Specific examples of the compound having a hydroxyl group used in the present invention include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, isobutyl alcohol, sec-butyl alcohol, tert-butyl alcohol, cyclohexanol, Examples thereof include alcohols such as ethylene glycol; phenol compounds such as phenol and naphthol. Among these, alcohol having 1 to 3 carbon atoms is preferable. As a preferred embodiment, a form in which methyl methacrylate is produced by reacting with methanol can be mentioned. The amount of the compound having a hydroxyl group used is such that the amount of water present in the reaction system is 40,000 mol or less with respect to 1 mol of the Group 10 metal compound, depending on the amount of water contained in the compound having the hydroxyl group. It is preferable to adjust. The amount of water contained in the compound having a hydroxyl group is preferably 1000 ppm by weight or less, more preferably 750 ppm by weight or less, further preferably 500 ppm by weight or less, and particularly preferably 100 ppm by weight or less. As for the usage-amount of the compound which has this hydroxyl group with respect to 1 mol of methyl acetylene, 1 mol or more is preferable and 1-5 mol is preferable.

  In the present invention, the amount of water present in the reaction system is preferably 40000 mol or less, more preferably 4000 mol or less, further preferably 1000 mol or less, and further preferably 500 mol or less with respect to 1 mol of the Group 10 metal compound. More preferred.

  In the reaction of the present invention, the use of a solvent is not essential, but it is preferable to lower the partial pressure of methylacetylene / propadiene. Suitably, the compound having the hydroxyl group is used in excess of the solvent. However, it is possible to use another solvent separately. Another solvent that can be used and the amount of the solvent used are not particularly limited as long as they do not greatly inhibit the reaction, but aromatic hydrocarbons, aliphatic hydrocarbons, sulfoxides, sulfones, esters, ketones, ethers Amides, alcohols, ionic liquids and mixtures thereof. Specific examples of the solvent include toluene, xylene, hexane, cyclohexane, heptane, octane, dimethyl sulfoxide, sulfolane, methyl acetate, ethyl acetate, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, acetone, methyl ethyl ketone, Examples include anisole, dimethoxyethane, diethyl ether, tetrahydrofuran, diglyme, dibutyl ether, dimethylformamide, N-methylpyrrolidone, dimethylacetamide and mixtures thereof.

  In the reaction of the present invention, phenothiazine, 2,6-di-tert-butyl-4-methylphenol, 2,4-dimethyl-6-tert-butylphenol, 1,1,3-tris (5-tert-butyl- Polymerization inhibitors such as 4-hydroxy-2-methylphenyl) butane and hydroquinone may be used, and the amount used is appropriately set.

  In the reaction, the reaction pressure is not particularly limited, but is preferably 0.2 to 10 MPa (absolute pressure), more preferably 0.5 to 7 MPa (absolute pressure). The carbon monoxide partial pressure at this time is not particularly limited, but is preferably 0.2 to 10 MPa (absolute pressure), more preferably 0.5 to 7 MPa (absolute pressure).

In the present invention, the partial pressure of carbon monoxide is lowered during the reaction. Incidentally, “lowering the partial pressure of carbon monoxide during the reaction” means that the reaction is started by bringing the catalyst, the compound having a hydroxyl group and methylacetylene into contact at a predetermined temperature and a predetermined partial pressure of carbon monoxide. This means that the partial pressure of carbon monoxide in the reaction system is lowered between the end of the reaction and the end of the reaction. The reaction is completed by reducing the partial pressure of carbon monoxide in the reaction system and continuing the reaction for a predetermined time, and then starting cooling for recovering the reaction liquid, or oxidizing monoxide for recovering the reaction liquid. This is the time when the purge of carbon starts. The partial pressure of carbon monoxide is preferably lowered by 0.1 MPa or more during the reaction, more preferably by 0.2 MPa or more, and further preferably by 0.5 MPa or more. The partial pressure of carbon monoxide may be lowered at a constant rate during the reaction, or may be lowered stepwise in a plurality of stages. When the partial pressure of carbon monoxide at the start of the reaction is P ₀ and the partial pressure of carbon monoxide after lowering the partial pressure of carbon monoxide during the reaction is P ₀ ′, P ₀ > P It is preferable to reduce the partial pressure of carbon monoxide so as to be ₀ ′.

  The partial pressure of carbon monoxide refers to the partial pressure of carbon monoxide in the gas phase portion in the reaction system. For example, when the molar fraction of carbon monoxide in the gas in the gas phase is 1, the carbon monoxide partial pressure is the same as the reaction pressure. For example, when the gas in the gas phase contains a component other than carbon monoxide, the value is calculated by multiplying the reaction pressure by the mole fraction of carbon monoxide in the gas in the gas phase. In addition, when the gas in the gas phase part contains components other than carbon monoxide, the total partial pressure of each component other than the carbon monoxide is calculated, and the total value is subtracted from the reaction pressure. The partial pressure of carbon can be determined. When lowering the partial pressure of carbon monoxide during the reaction, it is preferable to lower the reaction pressure and lower the partial pressure of carbon monoxide.

  In the present invention, the catalyst, the hydroxyl group-containing compound and methylacetylene are brought into contact with each other under a predetermined partial pressure of carbon monoxide, the reaction is started and the carbon monoxide content in the reaction system is measured between the start of the reaction and the end of the reaction. Reduce pressure. The partial pressure of carbon monoxide at the start of lowering the partial pressure of carbon monoxide is preferably 1.0 MPa (absolute pressure) or more, more preferably 1.3 to 10 MPa (absolute pressure). More preferably, it is 0.7 to 7.0 MPa (absolute pressure), and even more preferably 2.0 to 5.0 MPa (absolute pressure). The partial pressure of carbon monoxide is preferably lowered to 0.1 to 5.0 MPa (absolute pressure), more preferably 0.2 to 2.0 MPa (absolute pressure), 0.2 It is further preferable to lower the pressure to ˜1.5 MPa (absolute pressure). The timing for starting to lower the partial pressure of carbon monoxide is preferably within the range of 1 to 70%, and more preferably within the range of 5 to 60%, of methylacetylene. The reaction time at the time of starting to lower the partial pressure of carbon monoxide is preferably 300 minutes or less, more preferably 1 to 300 minutes, and even more preferably 5 to 200 minutes.

When the partial pressure of carbon monoxide is lowered step by step, the number of steps, the difference in partial pressure of carbon monoxide per step, the holding time for each step, etc. can be set as appropriate. When lowering the partial pressure of carbon, the catalyst, the compound having a hydroxyl group, and methylacetylene are brought into contact with each other under a predetermined partial pressure of carbon monoxide (P _A ), then held for a predetermined time, and then carbon monoxide. Is reduced to a predetermined partial pressure of carbon monoxide (P _B ) that is lower than the partial pressure P _A ′ of carbon monoxide after such holding, and then held for a predetermined time, The pressure may be lowered to a predetermined carbon monoxide partial pressure (P _C ) lower than the carbon monoxide partial pressure P _B ′ after holding (where P _A ≦ P _A ′, P _B ≦ P _B ′). Incidentally, after the contacted under P _A, without retaining a predetermined time, the partial pressure of carbon monoxide, the lower than P _A, be started down to the partial pressure of a given carbon monoxide (P _B) Good. The P _A and P _A ′ are preferably 1.0 MPa (absolute pressure) or more, more preferably 1.3 to 10 MPa (absolute pressure), and 1.7 to 7.0 MPa (absolute pressure). ) Is more preferable, and 2.0 to 5.0 MPa (absolute pressure) is even more preferable. The P _B and P _B ′ are preferably 0.6 to 5.0 MPa (absolute pressure), more preferably 1.0 to 2.5 MPa (absolute pressure), and 1.0 to 2 More preferably, the pressure is 0.0 MPa (absolute pressure) (provided that P _A ′ ≧ P _A > P _B ). As the _{P C,} it is preferably 0.1～2.5MPa (absolute pressure), more preferably 0.2～2.0MPa (absolute pressure), 0.2 to 1.5 MPa (absolute more preferably a pressure) (provided, however, that _{P B '≧ P B> P} C). The conversion rate of methylacetylene at the time when the partial pressure of carbon monoxide starts to be lowered from P _A ′ to P _B is preferably in the range of 1 to 60%, more preferably in the range of 5 to 50%. The conversion of methyl acetylene in the time from the P _{B 'starts} lowering the partial pressure of carbon monoxide in the P _C, preferably in the range 10-75%, more preferably in the range 30 to 75% (provided that , When the partial pressure of carbon monoxide from P _B ′ to P _C is lower than the conversion rate of methyl acetylene at the time of starting to lower the partial pressure of carbon monoxide from P _A ′ to P _B. Acetylene conversion is higher). The reaction time at the time when the partial pressure of carbon monoxide starts to decrease from P _A ′ to P _B is preferably 200 minutes or less, more preferably 1 to 200 minutes, and even more preferably 5 to 200 minutes. The _{P B} 'reaction time at the time from the start lowering the partial pressure of carbon monoxide in the _{P C} is preferably 5 to 300 minutes, more preferably 100 to 300 minutes (however, the _{P A'} to the _{P B} from than the reaction time at the time of start lowering the partial pressure of carbon monoxide, is a slow one person reaction time at the time of the start lowering the partial pressure of carbon monoxide in the P _C from P _{B ').}

  As a method for reducing the partial pressure of carbon monoxide, for example, (a) carbon monoxide is not additionally supplied into the reaction system, or carbon monoxide in an amount smaller than the amount consumed by the reaction is additionally supplied into the reaction system. (B) a method of purging carbon monoxide out of the reaction system, and (c) a method of supplying a gas other than carbon monoxide into the reaction system. Among them, the method (a) is preferable. Two or more methods (a) to (c) may be combined as necessary. When reducing the partial pressure of carbon monoxide, the reaction pressure may be kept constant or the reaction pressure may be increased by the method (c) or the like. It is preferable to reduce the reaction pressure by the use of a gas other than carbon monoxide by the method (ii). Examples of the gas other than carbon monoxide include inert gases such as nitrogen, argon and helium, carbon dioxide and the like.

  In the above reaction, the reaction temperature is not particularly limited, but it is preferably carried out in the range of 20 to 100 ° C. In the reaction, the catalyst, the hydroxyl group-containing compound and methylacetylene are brought into contact at a predetermined reaction temperature under a predetermined partial pressure of carbon monoxide, the reaction is started, and the temperature is increased from the start to the end of the reaction. The reaction temperature may be increased. Such temperature increase is preferably performed so that the temperature difference between the reaction temperature at the start of temperature increase and the reaction temperature after the temperature increase is 3 ° C. or more. The temperature increase may be performed at a constant temperature increase rate or may be performed stepwise in a plurality of stages. Moreover, although reaction time is based also on conditions, such as a catalyst usage-amount, reaction temperature, reaction pressure, and carbon monoxide partial pressure, Preferably it is 0.5 to 48 hours. The embodiment of the reaction of the present invention in the reaction is not particularly limited, and may be, for example, a batch type or a continuous type.

  When performing the said reaction by a continuous type, the said reaction can be performed using the n reaction tank (n represents an integer greater than or equal to 2) connected in series. For example, the catalyst, carbon monoxide, a compound having a hydroxyl group and methylacetylene are supplied to a first reaction vessel, and the reaction mixture is continuously passed through a plurality of reactors connected in series, and monoxide is oxidized during the reaction. The reaction can be carried out continuously by lowering the partial pressure of carbon and extracting the reaction mixture from the nth reaction vessel. When the reaction is performed using n reaction tanks connected in series in series, the partial pressure of carbon monoxide in the nth reaction tank located at the most downstream in the flow direction of methylacetylene is the most upstream. The reaction is preferably carried out so as to be lower than the partial pressure of carbon monoxide in the first reaction tank located. Further, the partial pressure of carbon monoxide in the nth reaction tank located at the most downstream in the flow direction of methylacetylene is lower than the partial pressure of carbon monoxide in the first reaction tank located at the uppermost stream. When carrying out the reaction, the reaction is performed so that the reaction pressure in the nth reaction tank located at the most downstream in the flow direction of methylacetylene is lower than the reaction pressure in the first reaction tank located at the most upstream. It is preferable to implement. The n is preferably 7 or less.

  When the reaction is carried out continuously using two reaction vessels connected in series, the carbon monoxide partial pressure P1 of the first reaction vessel and the carbon monoxide content of the second reaction vessel lower than P1. The pressure difference from the pressure P2 (P1-P2) is preferably 0.1 MPa or more, more preferably P1-P2 is 0.2 MPa or more, and P1-P2 is 0.5 MPa. More preferably, the above is achieved. The P1 is preferably 1.0 MPa (absolute pressure) or more, more preferably 1.3 to 10 MPa (absolute pressure), and 1.7 to 7.0 MPa (absolute pressure). More preferably, it is still more preferably 2.0 to 5.0 MPa (absolute pressure). The P2 is preferably 0.1 to 5.0 MPa (absolute pressure), more preferably 0.2 to 2.0 MPa (absolute pressure), and 0.2 to 1.5 MPa (absolute pressure). More preferably, At the time when the reaction mixture extracted from the outlet of the first reaction tank is supplied to the second reaction tank, the conversion of methylacetylene is preferably in the range of 1 to 70%, and in the range of 5 to 60%. Is more preferable. 300 minutes or less are preferable, the total residence time until it distribute | circulates a 1st reaction tank and is supplied to a 2nd reaction tank is more preferable, 1-300 minutes are more preferable, and 5-200 minutes are more preferable.

  When n is an integer of 3 or more, the carbon monoxide partial pressure in at least one of the second to nth reaction tanks is lower than the carbon monoxide partial pressure P1 of the first reaction tank. Any carbon partial pressure may be used. Pressure difference (P1-Pmin) between the carbon monoxide partial pressure P1 of the first reaction tank and the carbon monoxide partial pressure Pmin in the reaction tank having the lowest carbon monoxide partial pressure among the second to nth reaction tanks. Is preferably 0.1 MPa or more, more preferably P1-Pmin is 0.2 MPa or more, and further preferably P1-Pmin is 0.5 MPa or more. A plurality of reaction vessels having a carbon monoxide partial pressure of Pmin may exist. Among the second to nth reaction tanks, at least in the nth reaction tank, the carbon monoxide partial pressure Pn is preferably lower than the carbon monoxide partial pressure P1, and more preferably Pmin. preferable. The P1 is preferably 1.0 MPa (absolute pressure) or more, more preferably 1.3 to 10 MPa (absolute pressure), and 1.7 to 7.0 MPa (absolute pressure). More preferably, it is still more preferably 2.0 to 5.0 MPa (absolute pressure). The Pmin is preferably 0.1 to 5.0 MPa (absolute pressure), more preferably 0.2 to 2.0 MPa (absolute pressure), and 0.2 to 1.5 MPa (absolute pressure). More preferably, When n is an integer of 3 or more and the reaction is carried out continuously using n reaction vessels connected in series, the carbon monoxide content in the upstream reaction vessel in two successive reaction vessels. The pressure Pu and the carbon monoxide partial pressure Pd in the downstream reaction tank are one so as to satisfy the relationship of Pu ≧ Pd (where Pu = Pd is not satisfied in all two consecutive reaction tanks). It is preferable to set the carbon oxide partial pressure.

  For example, when n = 3, the carbon monoxide partial pressure P1 of the first reaction tank is preferably 1.0 MPa (absolute pressure) or more, and preferably 1.3 to 10 MPa (absolute pressure). More preferably, it is more preferably 1.7 to 7.0 MPa (absolute pressure), and even more preferably 2.0 to 5.0 MPa (absolute pressure). The carbon monoxide partial pressure P2 of the second reaction tank is preferably 0.6 to 5.0 MPa (absolute pressure), more preferably 1.0 to 2.5 MPa (absolute pressure), More preferably, the pressure is 1.0 to 2.0 MPa (absolute pressure). The carbon monoxide partial pressure P3 of the third reaction tank is preferably 0.1 to 2.5 MPa (absolute pressure), more preferably 0.2 to 2.0 MPa (absolute pressure), More preferably, the pressure is 0.2 to 1.5 MPa (absolute pressure). P1, P2 and P3 are preferably P1> P2> P3. At the time when the reaction mixture extracted from the outlet of the first reaction tank is supplied to the second reaction tank, the methylacetylene conversion rate X1 is preferably in the range of 1 to 60%, preferably 5 to 50%. The range of is more preferable. When the reaction mixture extracted from the outlet of the second reaction tank is supplied to the third reaction tank, the total conversion of methylacetylene of the reaction in the first reaction tank and the reaction in the second reaction tank X2 is preferably in the range of 10 to 75%, more preferably in the range of 30 to 75% (provided that X1 <X2). The total residence time t1 from flowing through the first reaction tank to being supplied to the second reaction tank is preferably 200 minutes or less, more preferably 1 to 200 minutes, and even more preferably 5 to 200 minutes. The total residence time t2 from flowing through the first reaction tank and the second reaction tank to being supplied to the third reaction tank is preferably 5 to 300 minutes, more preferably 100 to 300 minutes (however, t1 <T2).

  By the reaction, a reaction mixture containing a methacrylic ester is obtained. Specific examples of the methacrylic acid ester obtained in the reaction include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, methacrylic acid. Mention may be made of methacrylic acid esters such as tert-butyl acid, cyclohexyl methacrylate, 2-hydroxyethyl methacrylate, phenyl methacrylate and naphthyl methacrylate. The post-treatment operation of the reaction mixture containing the methacrylic acid ester can be appropriately selected, and the methacrylic acid ester can be purified by combining treatments such as gas diffusion operation, distillation operation, and extraction operation. The compound having unreacted hydroxyl group, methylacetylene and carbon monoxide are preferably recycled. The catalyst recovered after the reaction is preferably recycled after subjecting to reactivation treatment as necessary. At the time of post-treatment of the reaction mixture containing a methacrylic acid ester, a polymerization inhibitor may be added, and examples of the polymerization inhibitor include the polymerization inhibitors exemplified above.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.

Example 1
(Preparation of catalyst solution)
In a Schlenk tube, 2.7 mg (0.0118 mmol) of palladium acetate and 200 mg (0.707 mmol) of diphenyl (6-methyl-2-pyridyl) phosphine were placed, and the gas phase was replaced with nitrogen. Methanol was added and mixed to obtain a solution. To the resulting solution, 0.23 ml (1.77 mmol) of N, N-dimethylaniline and 70 μl (1.06 mmol) of methanesulfonic acid were added and stirred at 40 ° C. for 2 hours to prepare a catalyst solution.

[Production of methyl methacrylate]
1.26 ml fraction of the catalyst solution obtained above (palladium 0.000295 mmol, diphenyl (6-methyl-2-pyridyl) phosphine 0.0177 mmol equivalent) was introduced into a stainless steel autoclave having an internal volume of 230 ml under a nitrogen atmosphere. In addition, 29 ml of methanol were introduced. The autoclave was cooled in an ethanol / dry ice bath, and 11.1 g of methylacetylene having a propadiene concentration of 2 ppm or less (purity: 99.9 mol%, methylacetylene content: 277 mmol, propadiene content: 0.0006 mmol or less) was introduced. Thereafter, it was pressurized with carbon monoxide (CO) and maintained at 1.1 MPa (absolute pressure). The ethanol / dry ice bath was removed, and the autoclave was heated in a 50 ° C. water bath while stirring the mixture in the autoclave, and the temperature of the mixture in the autoclave was adjusted to 50 ° C. After reaching 50 ° C., CO was pressurized to 1.8 MPa (absolute pressure) to initiate the reaction. Calculate the methyl acetylene partial pressure and methanol partial pressure in the gas phase at the start of the reaction from the amount of methyl acetylene and methanol, and the vapor pressure of methanol and the vapor pressure of methanol at 50 ° C. The partial pressure of nitrogen in the gas phase at the start of the reaction was determined by reducing the partial pressure of nitrogen, the partial pressure of methylacetylene and the partial pressure of methanol, and it was 1.4 MPa (absolute pressure).

  In order to keep the reaction pressure at 1.8 MPa (absolute pressure) for 90 minutes after the start of the reaction, the consumed amount of CO was constantly introduced by a pressure reducing valve. At 90 minutes from the start of the reaction, CO introduction was interrupted, the autoclave was sealed, and the mixture in the autoclave was continuously stirred. The methyl acetylene conversion rate 90 minutes after the start of the reaction was determined from the total amount of CO absorbed up to 90 minutes after the start of the reaction. As a result, it was 37%. The reaction starts from the amount of methyl acetylene, the amount of methanol and the amount of methyl methacrylate produced at 90 minutes after the start of the reaction, and the vapor pressure of methyl acetylene, the vapor pressure of methanol and the vapor pressure of methyl methacrylate at 50 ° C. 90 minutes after that, the methyl acetylene partial pressure, methanol partial pressure, and methyl methacrylate partial pressure in the gas phase were calculated. From the reaction pressure at 90 minutes after the start of the reaction, the nitrogen partial pressure, methyl The CO partial pressure at the time of 90 minutes after the reaction was started by reducing the acetylene partial pressure, methanol partial pressure, and methyl methacrylate partial pressure was 1.4 MPa (absolute pressure).

117 minutes after starting the reaction, the reaction pressure was 1.6 MPa (absolute pressure). The CO partial pressure at the time of 117 minutes after starting the reaction in the same manner as described above was 1.2 MPa (absolute pressure). The introduction of CO was resumed, and the reaction pressure was maintained at 1.6 MPa (absolute pressure) while continuing stirring for 117 minutes after the start of the reaction to 400 minutes after the start of the reaction, and then cooled. At 400 minutes after the start of the reaction, no CO absorption was observed. The reaction temperature is 50 ° C. for 90 minutes after the start of the reaction, 55 ° C. for 90 minutes to 200 minutes after the start of the reaction, and 200 minutes to 400 after the start of the reaction. The minutes were 65 ° C. When the reaction solution was quantitatively analyzed by gas chromatography (GC), the amount of methyl methacrylate produced was 7.9 × 10 ⁵ mol / Pd mol.

Example 2
(Preparation of catalyst solution)
A catalyst solution was prepared in the same manner as in Example 1 [Preparation of catalyst solution].

[Production of methyl methacrylate]
1.26 ml fraction of the catalyst solution obtained above (palladium 0.000295 mmol, diphenyl (6-methyl-2-pyridyl) phosphine 0.0177 mmol equivalent) was introduced into a stainless steel autoclave having an internal volume of 230 ml under a nitrogen atmosphere. In addition, 29 ml of methanol were introduced. The autoclave was cooled in an ethanol / dry ice bath, and 11.1 g of methylacetylene having a propadiene concentration of 2 ppm or less (purity: 99.9 mol%, methylacetylene content: 277 mmol, propadiene content: 0.0006 mmol or less) was introduced. Thereafter, it was pressurized with carbon monoxide (CO) and maintained at 1.1 MPa (absolute pressure). The ethanol / dry ice bath was removed, and the autoclave was heated in a 50 ° C. water bath while stirring the mixture in the autoclave, and the temperature of the mixture in the autoclave was adjusted to 50 ° C. After reaching 50 ° C., CO was pressurized to 2.1 MPa (absolute pressure) to initiate the reaction. When the CO partial pressure in the gas phase at the start of the reaction was determined in the same manner as in Example 1, it was 1.7 MPa (absolute pressure).

  In order to keep the reaction pressure at 2.1 MPa (absolute pressure) for 90 minutes after the start of the reaction, the consumed amount of CO was constantly introduced by a pressure reducing valve. At 90 minutes from the start of the reaction, CO introduction was interrupted, the autoclave was sealed, and the mixture in the autoclave was continuously stirred. The methyl acetylene conversion rate 90 minutes after the start of the reaction was determined from the total amount of CO absorbed up to 90 minutes after the start of the reaction. As a result, it was 37%. In the same manner as in Example 1, when the CO partial pressure at the time of 90 minutes after the reaction was started was determined, it was 1.7 MPa (absolute pressure).

135 minutes after starting the reaction, the reaction pressure became 1.6 MPa (absolute pressure). The CO partial pressure at the time of 135 minutes after starting the reaction in the same manner as in Example 1 was 1.3 MPa (absolute pressure). The introduction of CO was resumed, and the reaction pressure was maintained at 1.6 MPa (absolute pressure) while continuing stirring for 135 minutes after the reaction start to 400 minutes after the reaction start, and then cooled. At 400 minutes after the start of the reaction, no CO absorption was observed. The reaction temperature is 50 ° C. for 90 minutes after the start of the reaction, 55 ° C. for 90 minutes to 200 minutes after the start of the reaction, and 200 minutes to 400 after the start of the reaction. The minutes were 65 ° C. When the reaction solution was quantitatively analyzed by gas chromatography (GC), the amount of methyl methacrylate produced was 8.1 × 10 ⁵ mol / Pd mol.

Example 3
(Preparation of catalyst solution)
A catalyst solution was prepared in the same manner as in Example 1 [Preparation of catalyst solution].

[Production of methyl methacrylate]
1.26 ml fraction of the catalyst solution obtained above (palladium 0.000295 mmol, diphenyl (6-methyl-2-pyridyl) phosphine 0.0177 mmol equivalent) was introduced into a stainless steel autoclave having an internal volume of 230 ml under a nitrogen atmosphere. In addition, 29 ml of methanol were introduced. After cooling the autoclave in an ethanol / dry ice bath and introducing 11.3 g of methylacetylene having a propadiene concentration of 3 ppm (purity: 99.9 mol%, methylacetylene content: 282 mmol, propadiene content: 0.0008 mmol), It was pressurized with carbon monoxide (CO) and maintained at 1.1 MPa (absolute pressure). The ethanol / dry ice bath was removed, and the autoclave was heated in a 50 ° C. water bath while stirring the mixture in the autoclave, and the temperature of the mixture in the autoclave was adjusted to 50 ° C. After reaching 50 ° C., CO was pressurized to 2.1 MPa (absolute pressure) to initiate the reaction. When the CO partial pressure in the gas phase at the start of the reaction was determined in the same manner as in Example 1, it was 1.6 MPa (absolute pressure).

  In order to keep the reaction pressure at 2.1 MPa (absolute pressure) for 90 minutes after the start of the reaction, the consumed amount of CO was constantly introduced by a pressure reducing valve. At 90 minutes from the start of the reaction, CO introduction was interrupted, the autoclave was sealed, and the mixture in the autoclave was continuously stirred. The methyl acetylene conversion rate after 90 minutes from the start of the reaction was found to be 31% from the total amount of CO absorbed up to 90 minutes after the start of the reaction. In the same manner as in Example 1, when the CO partial pressure at the time of 90 minutes after the reaction was started was determined, it was 1.7 MPa (absolute pressure).

208 minutes after starting the reaction, the reaction pressure was 1.1 MPa (absolute pressure). The CO partial pressure at the time 208 minutes after the reaction was started in the same manner as in Example 1 was 0.7 MPa (absolute pressure). The introduction of CO was restarted, and the reaction pressure was maintained at 1.1 MPa (absolute pressure) while continuing stirring for 208 minutes after the start of the reaction to 400 minutes after the start of the reaction, and then cooled. At 400 minutes after the start of the reaction, no CO absorption was observed. The reaction temperature is 50 ° C. for 90 minutes after the start of the reaction, 55 ° C. for 90 minutes to 200 minutes after the start of the reaction, and 200 minutes to 400 after the start of the reaction. The minutes were 65 ° C. When the reaction solution was quantitatively analyzed by gas chromatography (GC), the amount of methyl methacrylate produced was 8.2 × 10 ⁵ mol / Pd mol.

Example 4
(Preparation of catalyst solution)
A catalyst solution was prepared in the same manner as in Example 1 [Preparation of catalyst solution].

[Production of methyl methacrylate]
1.26 ml fraction of the catalyst solution obtained above (palladium 0.000295 mmol, diphenyl (6-methyl-2-pyridyl) phosphine 0.0177 mmol equivalent) was introduced into a stainless steel autoclave having an internal volume of 230 ml under a nitrogen atmosphere. In addition, 29 ml of methanol were introduced. After cooling the autoclave in an ethanol / dry ice bath and introducing 11.4 g of methylacetylene having a propadiene concentration of 3 ppm (purity: 99.9 mol%, methylacetylene content: 284 mmol, propadiene content: 0.0008 mmol), It was pressurized with carbon monoxide (CO) and maintained at 1.1 MPa (absolute pressure). The ethanol / dry ice bath was removed, and the autoclave was heated in a 50 ° C. water bath while stirring the mixture in the autoclave, and the temperature of the mixture in the autoclave was adjusted to 50 ° C. After reaching 50 ° C., CO was pressurized to 2.6 MPa (absolute pressure) to initiate the reaction. When the CO partial pressure in the gas phase at the start of the reaction was determined in the same manner as in Example 1, it was 2.1 MPa (absolute pressure).

  In order to maintain the reaction pressure at 2.6 MPa (absolute pressure) for 90 minutes after the start of the reaction, the consumed amount of CO was constantly introduced by a pressure reducing valve. At 90 minutes from the start of the reaction, CO introduction was interrupted, the autoclave was sealed, and the mixture in the autoclave was continuously stirred. The methyl acetylene conversion rate 90 minutes after the start of the reaction was determined from the total amount of CO absorbed up to 90 minutes after the start of the reaction, and found to be 36%. In the same manner as in Example 1, when the CO partial pressure at the time of 90 minutes from the start of the reaction was determined, it was 2.2 MPa (absolute pressure).

208 minutes after starting the reaction, the reaction pressure was 1.6 MPa (absolute pressure). The CO partial pressure at the time of 208 minutes after the reaction was started in the same manner as in Example 1 was found to be 1.2 MPa (absolute pressure). The introduction of CO was resumed, and the reaction pressure was maintained at 1.6 MPa (absolute pressure) while continuing stirring for 208 minutes after the start of the reaction to 400 minutes after the start of the reaction, and then cooled. At 400 minutes after the start of the reaction, no CO absorption was observed. The reaction temperature is 50 ° C. for 90 minutes after the start of the reaction, 55 ° C. for 90 minutes to 200 minutes after the start of the reaction, and 200 minutes to 400 after the start of the reaction. The minutes were 65 ° C. When the reaction solution was quantitatively analyzed by gas chromatography (GC), the amount of methyl methacrylate produced was 8.5 × 10 ⁵ mol / Pd mol.

Example 5
(Preparation of catalyst solution)
A catalyst solution was prepared in the same manner as in Example 1 [Preparation of catalyst solution].

[Production of methyl methacrylate]
1.26 ml fraction of the catalyst solution obtained above (palladium 0.000295 mmol, diphenyl (6-methyl-2-pyridyl) phosphine 0.0177 mmol equivalent) was introduced into a stainless steel autoclave having an internal volume of 230 ml under a nitrogen atmosphere. In addition, 29 ml of methanol were introduced. After cooling the autoclave in an ethanol / dry ice bath and introducing 11.3 g of methylacetylene having a propadiene concentration of 3 ppm (purity: 99.9 mol%, methylacetylene content: 282 mmol, propadiene content: 0.0008 mmol), It was pressurized with carbon monoxide (CO) and maintained at 1.1 MPa (absolute pressure). The ethanol / dry ice bath was removed, and the autoclave was heated in a 50 ° C. water bath while stirring the mixture in the autoclave, and the temperature of the mixture in the autoclave was adjusted to 50 ° C. After reaching 50 ° C., CO was pressurized to 2.6 MPa (absolute pressure) to initiate the reaction. When the CO partial pressure in the gas phase at the start of the reaction was determined in the same manner as in Example 1, it was 2.1 MPa (absolute pressure).

  In order to maintain the reaction pressure at 2.6 MPa (absolute pressure) for 90 minutes after the start of the reaction, the consumed amount of CO was constantly introduced by a pressure reducing valve. At 90 minutes from the start of the reaction, CO introduction was interrupted, the autoclave was sealed, and the mixture in the autoclave was continuously stirred. The methyl acetylene conversion rate 90 minutes after the start of the reaction was determined from the total amount of CO absorbed up to 90 minutes after the start of the reaction, and found to be 36%. In the same manner as in Example 1, when the CO partial pressure at the time of 90 minutes from the start of the reaction was determined, it was 2.2 MPa (absolute pressure).

275 minutes after the start of the reaction, the reaction pressure became 1.1 MPa (absolute pressure). The CO partial pressure at the time of 275 minutes after starting the reaction in the same manner as in Example 1 was 0.8 MPa (absolute pressure). The introduction of CO was restarted, and the reaction pressure was maintained at 1.1 MPa (absolute pressure) while continuing stirring for 275 minutes after the start of the reaction to 400 minutes after the start of the reaction, and then cooled. At 400 minutes after the start of the reaction, no CO absorption was observed. The reaction temperature is 50 ° C. for 90 minutes after the start of the reaction, 55 ° C. for 90 minutes to 200 minutes after the start of the reaction, and 200 minutes to 400 after the start of the reaction. The minutes were 65 ° C. When the reaction solution was quantitatively analyzed by gas chromatography (GC), the amount of methyl methacrylate produced was 8.8 × 10 ⁵ mol / Pd mol.

Example 6
(Preparation of catalyst solution)
A catalyst solution was prepared in the same manner as in Example 1 [Preparation of catalyst solution].

[Production of methyl methacrylate]
1.26 ml fraction of the catalyst solution obtained above (palladium 0.000295 mmol, diphenyl (6-methyl-2-pyridyl) phosphine 0.0177 mmol equivalent) was introduced into a stainless steel autoclave having an internal volume of 230 ml under a nitrogen atmosphere. In addition, 29 ml of methanol were introduced. The autoclave was cooled in an ethanol / dry ice bath, and 12.7 g of methylacetylene having a propadiene concentration of 2 ppm or less (purity: 99.9 mol%, methylacetylene content: 317 mmol, propadiene content: 0.0007 mmol or less) was introduced. Thereafter, it was pressurized with carbon monoxide (CO) and maintained at 1.1 MPa (absolute pressure). The ethanol / dry ice bath was removed, and the autoclave was heated in a 50 ° C. water bath while stirring the mixture in the autoclave, and the temperature of the mixture in the autoclave was adjusted to 50 ° C. After reaching 50 ° C., CO was pressurized to 2.6 MPa (absolute pressure) to initiate the reaction. When the CO partial pressure in the gas phase at the start of the reaction was determined in the same manner as in Example 1, it was 2.1 MPa (absolute pressure).

  In order to maintain the reaction pressure at 2.6 MPa (absolute pressure) for 90 minutes after the start of the reaction, the consumed amount of CO was constantly introduced by a pressure reducing valve. At 90 minutes from the start of the reaction, CO introduction was interrupted, the autoclave was sealed, and the mixture in the autoclave was continuously stirred. The methyl acetylene conversion after 90 minutes from the start of the reaction was found to be 34% from the total amount of CO absorbed up to 90 minutes after the start of the reaction. In the same manner as in Example 1, when the CO partial pressure at the time of 90 minutes from the start of the reaction was determined, it was 2.2 MPa (absolute pressure).

246 minutes after the start of the reaction, the reaction pressure became 1.1 MPa (absolute pressure). The CO partial pressure at the time of 246 minutes after starting the reaction in the same manner as in Example 1 was 0.8 MPa (absolute pressure). The introduction of CO was restarted, and the reaction pressure was maintained at 1.1 MPa (absolute pressure) while continuing stirring for 246 minutes after the start of the reaction to 400 minutes after the start of the reaction, and then cooled. At 400 minutes after the start of the reaction, no CO absorption was observed. The reaction temperature is 50 ° C. for 90 minutes after the start of the reaction, 55 ° C. for 90 minutes to 200 minutes after the start of the reaction, and 200 minutes to 400 after the start of the reaction. The minutes were 65 ° C. When the reaction solution was quantitatively analyzed by gas chromatography (GC), the amount of methyl methacrylate produced was 9.0 × 10 ⁵ mol / Pd mol.

Example 7
(Preparation of catalyst solution)
A catalyst solution was prepared in the same manner as in Example 1 [Preparation of catalyst solution].

[Production of methyl methacrylate]
1.26 ml fraction of the catalyst solution obtained above (palladium 0.000295 mmol, diphenyl (6-methyl-2-pyridyl) phosphine 0.0177 mmol equivalent) was introduced into a stainless steel autoclave having an internal volume of 230 ml under a nitrogen atmosphere. In addition, 29 ml of methanol were introduced. The autoclave was cooled in an ethanol / dry ice bath, and 12.8 g of methylacetylene having a propadiene concentration of 2 ppm or less (purity: 99.9 mol%, methylacetylene content: 319 mmol, propadiene content: 0.0007 mmol or less) was introduced. Thereafter, it was pressurized with carbon monoxide (CO) and maintained at 1.1 MPa (absolute pressure). The ethanol / dry ice bath was removed, and the autoclave was heated in a 50 ° C. water bath while stirring the mixture in the autoclave, and the temperature of the mixture in the autoclave was adjusted to 50 ° C. After reaching 50 ° C., CO was pressurized to 2.6 MPa (absolute pressure) to initiate the reaction. When the CO partial pressure in the gas phase at the start of the reaction was determined in the same manner as in Example 1, it was 2.1 MPa (absolute pressure).

  In order to maintain the reaction pressure at 2.6 MPa (absolute pressure) for 90 minutes after the start of the reaction, the consumed amount of CO was constantly introduced by a pressure reducing valve. At 90 minutes from the start of the reaction, CO introduction was interrupted, the autoclave was sealed, and the mixture in the autoclave was continuously stirred. The methyl acetylene conversion after 90 minutes from the start of the reaction was found to be 34% from the total amount of CO absorbed up to 90 minutes after the start of the reaction. In the same manner as in Example 1, when the CO partial pressure at the time of 90 minutes from the start of the reaction was determined, it was 2.2 MPa (absolute pressure).

After 410 minutes from the start of the reaction, it was cooled. At 410 minutes after the start of the reaction, the reaction pressure was 0.7 MPa (absolute pressure), and no CO absorption was observed. The CO partial pressure at 410 minutes after the reaction was started in the same manner as in Example 1 was 0.4 MPa (absolute pressure). The reaction temperature is 50 ° C. for 90 minutes after the start of the reaction, 55 ° C. for 90 minutes after the start of the reaction to 200 minutes after the start of the reaction, and 200 minutes after the start of the reaction to 410 after the start of the reaction. The minutes were 65 ° C. When the reaction solution was quantitatively analyzed by gas chromatography (GC), the amount of methyl methacrylate produced was 9.1 × 10 ⁵ mol / Pd mol.

Example 8
(Preparation of catalyst solution)
A catalyst solution was prepared in the same manner as in Example 1 [Preparation of catalyst solution].

[Production of methyl methacrylate]
1.26 ml fraction of the catalyst solution obtained above (palladium 0.000295 mmol, diphenyl (6-methyl-2-pyridyl) phosphine 0.0177 mmol equivalent) was introduced into a stainless steel autoclave having an internal volume of 230 ml under a nitrogen atmosphere. In addition, 29 ml of methanol were introduced. The autoclave was cooled in an ethanol / dry ice bath, and 13.0 g of methylacetylene having a propadiene concentration of 2 ppm or less (purity: 99.9 mol%, methylacetylene content: 324 mmol, propadiene content: 0.0007 mmol or less) was introduced. Thereafter, it was pressurized with carbon monoxide (CO) and maintained at 1.1 MPa (absolute pressure). The ethanol / dry ice bath was removed, and the autoclave was heated in a 50 ° C. water bath while stirring the mixture in the autoclave, and the temperature of the mixture in the autoclave was adjusted to 50 ° C. After reaching 50 ° C., CO was pressurized to 3.1 MPa (absolute pressure) to initiate the reaction. When the CO partial pressure in the gas phase at the start of the reaction was determined in the same manner as in Example 1, it was 2.6 MPa (absolute pressure).

  In order to keep the reaction pressure at 3.1 MPa (absolute pressure) for 30 minutes after the start of the reaction, consumed CO was constantly introduced by a pressure reducing valve. At 30 minutes after the start of the reaction, CO introduction was interrupted, the autoclave was sealed, and stirring of the mixture in the autoclave was continued. The methyl acetylene conversion rate 30 minutes after the start of the reaction was determined from the total amount of CO absorbed for 30 minutes after the start of the reaction, and found to be 9%. In the same manner as in Example 1, the CO partial pressure at the time point of 90 minutes after the reaction was started was found to be 2.7 MPa (absolute pressure).

364 minutes after the start of the reaction, the reaction pressure became 0.6 MPa (absolute pressure). The CO partial pressure at the time of 364 minutes after the reaction was started in the same manner as in Example 1 was 0.3 MPa (absolute pressure). The introduction of CO was resumed, and the reaction pressure was maintained at 0.6 MPa (absolute pressure) while continuing stirring for 364 minutes after the start of the reaction to 410 minutes after the start of the reaction, and then cooled. At 410 minutes after the start of the reaction, no CO absorption was observed. The reaction temperature is 50 ° C. for 90 minutes after the start of the reaction, 55 ° C. for 90 minutes after the start of the reaction to 200 minutes after the start of the reaction, and 200 minutes after the start of the reaction to 410 after the start of the reaction. The minutes were 65 ° C. When the reaction solution was quantitatively analyzed by gas chromatography (GC), the amount of methyl methacrylate produced was 8.8 × 10 ⁵ mol / Pd mol.

Example 9
(Preparation of catalyst solution)
A catalyst solution was prepared in the same manner as in Example 1 [Preparation of catalyst solution].

[Production of methyl methacrylate]
1.26 ml fraction of the catalyst solution obtained above (palladium 0.000295 mmol, diphenyl (6-methyl-2-pyridyl) phosphine 0.0177 mmol equivalent) was introduced into a stainless steel autoclave having an internal volume of 230 ml under a nitrogen atmosphere. In addition, 29 ml of methanol were introduced. The autoclave was cooled in an ethanol / dry ice bath, and 12.9 g of methylacetylene having a propadiene concentration of 2 ppm or less (purity: 99.8 mol%, methylacetylene content: 321 mmol, propadiene content: 0.0007 mmol or less) was introduced. Thereafter, it was pressurized with carbon monoxide (CO) and maintained at 1.1 MPa (absolute pressure). The ethanol / dry ice bath was removed, and the autoclave was heated in a 50 ° C. water bath while stirring the mixture in the autoclave, and the temperature of the mixture in the autoclave was adjusted to 50 ° C. After reaching 50 ° C., CO was pressurized to 2.6 MPa (absolute pressure) to initiate the reaction. When the CO partial pressure in the gas phase at the start of the reaction was determined in the same manner as in Example 1, it was 2.1 MPa (absolute pressure).

  In order to keep the reaction pressure at 2.6 MPa (absolute pressure) for 30 minutes after the start of the reaction, the consumed amount of CO was constantly introduced by a pressure reducing valve. At 30 minutes after the start of the reaction, CO introduction was interrupted, the autoclave was sealed, and stirring of the mixture in the autoclave was continued. The methyl acetylene conversion rate 30 minutes after the start of the reaction was found to be 12% from the total amount of CO absorbed until 30 minutes after the start of the reaction. In the same manner as in Example 1, the CO partial pressure at 30 minutes after the start of the reaction was determined to be 2.2 MPa (absolute pressure).

145 minutes after starting the reaction, the reaction pressure became 1.1 MPa (absolute pressure). The CO partial pressure at the time of 145 minutes after the reaction was started in the same manner as in Example 1 was 0.7 MPa (absolute pressure). The introduction of CO was resumed, and the reaction pressure was maintained at 1.1 MPa (absolute pressure) while continuing stirring for 145 minutes after the start of the reaction to 400 minutes after the start of the reaction, and then cooled. At 400 minutes after the start of the reaction, no CO absorption was observed. The reaction temperature is 50 ° C. for 90 minutes after the start of the reaction, 55 ° C. for 90 minutes to 200 minutes after the start of the reaction, and 200 minutes to 400 after the start of the reaction. The minutes were 65 ° C. When the reaction solution was quantitatively analyzed by gas chromatography (GC), the amount of methyl methacrylate produced was 8.5 × 10 ⁵ mol / Pd mol.

Example 10
(Preparation of catalyst solution)
A catalyst solution was prepared in the same manner as in Example 1 [Preparation of catalyst solution].

[Production of methyl methacrylate]
1.26 ml fraction of the catalyst solution obtained above (palladium 0.000295 mmol, diphenyl (6-methyl-2-pyridyl) phosphine 0.0177 mmol equivalent) was introduced into a stainless steel autoclave having an internal volume of 230 ml under a nitrogen atmosphere. In addition, 29 ml of methanol were introduced. The autoclave was cooled in an ethanol / dry ice bath, and 12.7 g of methylacetylene having a propadiene concentration of 2 ppm or less (purity: 99.8 mol%, methylacetylene content: 316 mmol, propadiene content: 0.0007 mmol or less) was introduced. Thereafter, it was pressurized with carbon monoxide (CO) and maintained at 1.1 MPa (absolute pressure). The ethanol / dry ice bath was removed, and the autoclave was heated in a 50 ° C. water bath while stirring the mixture in the autoclave, and the temperature of the mixture in the autoclave was adjusted to 50 ° C. After reaching 50 ° C., CO was pressurized to 2.6 MPa (absolute pressure) to initiate the reaction. When the CO partial pressure in the gas phase at the start of the reaction was determined in the same manner as in Example 1, it was 2.1 MPa (absolute pressure).

  In order to keep the reaction pressure at 2.6 MPa (absolute pressure) for 150 minutes after the start of the reaction, the consumed amount of CO was constantly introduced by a pressure reducing valve. At 150 minutes after the start of the reaction, CO introduction was interrupted, the autoclave was sealed, and stirring of the mixture in the autoclave was continued. The methyl acetylene conversion rate after 150 minutes from the start of the reaction was determined from the total amount of CO absorbed until 150 minutes after the start of the reaction, and was found to be 56%. In the same manner as in Example 1, the CO partial pressure at the time of 150 minutes after the reaction was started was determined to be 2.3 MPa (absolute pressure).

After 400 minutes from the start of the reaction, it was cooled. At 400 minutes after the start of the reaction, the reaction pressure was 1.3 MPa (absolute pressure), and no CO absorption was observed. The CO partial pressure at 400 minutes after the reaction was started in the same manner as in Example 1 was 1.1 MPa (absolute pressure). The reaction temperature is 50 ° C. for 90 minutes after the start of the reaction, 55 ° C. for 90 minutes to 200 minutes after the start of the reaction, and 200 minutes to 400 after the start of the reaction. The minutes were 65 ° C. When the reaction solution was quantitatively analyzed by gas chromatography (GC), the amount of methyl methacrylate produced was 9.0 × 10 ⁵ mol / Pd mol.

Example 11
(Preparation of catalyst solution)
A catalyst solution was prepared in the same manner as in Example 1 [Preparation of catalyst solution].

[Production of methyl methacrylate]
1.26 ml fraction of the catalyst solution obtained above (palladium 0.000295 mmol, diphenyl (6-methyl-2-pyridyl) phosphine 0.0177 mmol equivalent) was introduced into a stainless steel autoclave having an internal volume of 230 ml under a nitrogen atmosphere. In addition, 29 ml of methanol were introduced. The autoclave was cooled in an ethanol / dry ice bath and 13.1 g of methylacetylene having a propadiene concentration of 2 ppm or less (purity: 99.8 mol%, methylacetylene content: 326 mmol, propadiene content: 0.0007 mmol or less) was introduced. Thereafter, it was pressurized with carbon monoxide (CO) and maintained at 1.1 MPa (absolute pressure). The ethanol / dry ice bath was removed, and the autoclave was heated in a 50 ° C. water bath while stirring the mixture in the autoclave, and the temperature of the mixture in the autoclave was adjusted to 50 ° C. After reaching 50 ° C., CO was pressurized to 2.6 MPa (absolute pressure) to initiate the reaction. When the CO partial pressure in the gas phase at the start of the reaction was determined in the same manner as in Example 1, it was 2.1 MPa (absolute pressure).

  In order to keep the reaction pressure at 2.6 MPa (absolute pressure) for 60 minutes after the start of the reaction, the consumed amount of CO was constantly introduced by a pressure reducing valve. At 60 minutes after the start of the reaction, CO introduction was interrupted, the autoclave was sealed, and the mixture in the autoclave was continuously stirred. The methyl acetylene conversion rate after 60 minutes from the start of the reaction was calculated from the total amount of CO absorbed up to 60 minutes after the start of the reaction. In the same manner as in Example 1, when the CO partial pressure at the time of 60 minutes from the start of the reaction was determined, it was 2.2 MPa (absolute pressure).

  129 minutes after starting the reaction, the reaction pressure became 1.8 MPa (absolute pressure). The CO partial pressure at the time of 129 minutes after starting the reaction in the same manner as in Example 1 was 1.4 MPa (absolute pressure). The introduction of CO was resumed, and the reaction pressure was maintained at 1.8 MPa (absolute pressure) while stirring was continued for 129 minutes after the start of the reaction to 189 minutes after the start of the reaction. At 189 minutes from the start of the reaction, the introduction of CO was interrupted, the autoclave was sealed, and stirring of the mixture in the autoclave was continued. The methyl acetylene conversion after 189 minutes from the start of the reaction was found to be 61% from the total amount of CO absorbed until 189 minutes after the start of the reaction. When the CO partial pressure at the time of 189 minutes from the start of the reaction was determined in the same manner as in Example 1, it was 1.5 MPa (absolute pressure).

306 minutes after the start of the reaction, the reaction pressure became 1.1 MPa (absolute pressure). The CO partial pressure at the time point of 306 minutes after the reaction was started in the same manner as in Example 1 was 0.8 MPa (absolute pressure). The introduction of CO was resumed, and the reaction pressure was maintained at 1.1 MPa (absolute pressure) while continuing stirring for 306 minutes after the start of the reaction to 400 minutes after the start of the reaction, and then cooled. At 400 minutes after the start of the reaction, no CO absorption was observed. The reaction temperature is 50 ° C. for 90 minutes after the start of the reaction, 55 ° C. for 90 minutes to 200 minutes after the start of the reaction, and 200 minutes to 400 after the start of the reaction. The minutes were 65 ° C. When the reaction solution was quantitatively analyzed by gas chromatography (GC), the amount of methyl methacrylate produced was 8.8 × 10 ⁵ mol / Pd mol.

Example 12
(Preparation of catalyst solution)
A catalyst solution was prepared in the same manner as in Example 1 [Preparation of catalyst solution].

[Production of methyl methacrylate]
1.26 ml fraction of the catalyst solution obtained above (palladium 0.000295 mmol, diphenyl (6-methyl-2-pyridyl) phosphine 0.0177 mmol equivalent) was introduced into a stainless steel autoclave having an internal volume of 230 ml under a nitrogen atmosphere. In addition, 29 ml of methanol were introduced. The autoclave was cooled in an ethanol / dry ice bath, and 12.8 g of methylacetylene having a propadiene concentration of 2 ppm or less (purity: 99.8 mol%, methylacetylene content: 319 mmol, propadiene content: 0.0007 mmol or less) was introduced. Thereafter, it was pressurized with carbon monoxide (CO) and maintained at 1.1 MPa (absolute pressure). The ethanol / dry ice bath was removed, and the autoclave was heated in a 50 ° C. water bath while stirring the mixture in the autoclave, and the temperature of the mixture in the autoclave was adjusted to 50 ° C. After reaching 50 ° C., CO was pressurized to 2.6 MPa (absolute pressure) to initiate the reaction. When the CO partial pressure in the gas phase at the start of the reaction was determined in the same manner as in Example 1, it was 2.1 MPa (absolute pressure).

  In order to keep the reaction pressure at 2.6 MPa (absolute pressure) for 60 minutes after the start of the reaction, the consumed amount of CO was constantly introduced by a pressure reducing valve. At 60 minutes after the start of the reaction, CO introduction was interrupted, the autoclave was sealed, and the mixture in the autoclave was continuously stirred. The methyl acetylene conversion rate 60 minutes after the start of the reaction was determined from the total amount of CO absorbed until 60 minutes after the start of the reaction. In the same manner as in Example 1, when the CO partial pressure at the time of 60 minutes from the start of the reaction was determined, it was 2.2 MPa (absolute pressure).

  130 minutes after starting the reaction, the reaction pressure became 1.8 MPa (absolute pressure). The CO partial pressure at 130 minutes after the reaction was started in the same manner as in Example 1 was 1.4 MPa (absolute pressure). The introduction of CO was restarted, and the reaction pressure was maintained at 1.8 MPa (absolute pressure) while stirring was continued for 130 minutes after the start of the reaction to 160 minutes after the start of the reaction. At 160 minutes from the start of the reaction, CO introduction was interrupted, the autoclave was sealed, and the mixture in the autoclave was continuously stirred. The methyl acetylene conversion rate after 160 minutes from the start of the reaction was calculated from the total amount of CO absorbed from the start of the reaction up to 160 minutes and found to be 57%. In the same manner as in Example 1, when the CO partial pressure at the point of 160 minutes from the start of the reaction was determined, it was 1.5 MPa (absolute pressure).

263 minutes after the start of the reaction, the reaction pressure became 1.1 MPa (absolute pressure). The CO partial pressure at the time of 263 minutes after starting the reaction in the same manner as in Example 1 was 0.8 MPa (absolute pressure). The introduction of CO was resumed, and the reaction pressure was maintained at 1.1 MPa (absolute pressure) while continuing stirring for 263 minutes after the start of the reaction to 400 minutes after the start of the reaction, and then cooled. At 400 minutes after the start of the reaction, no CO absorption was observed. The reaction temperature is 50 ° C. for 90 minutes after the start of the reaction, 55 ° C. for 90 minutes to 200 minutes after the start of the reaction, and 200 minutes to 400 after the start of the reaction. The minutes were 65 ° C. When the reaction solution was quantitatively analyzed by gas chromatography (GC), the amount of methyl methacrylate produced was 8.8 × 10 ⁵ mol / Pd mol.

Example 13
(Preparation of catalyst solution)
A catalyst solution was prepared in the same manner as in Example 1 [Preparation of catalyst solution].

[Production of methyl methacrylate]
1.26 ml fraction of the catalyst solution obtained above (palladium 0.000295 mmol, diphenyl (6-methyl-2-pyridyl) phosphine 0.0177 mmol equivalent) was introduced into a stainless steel autoclave having an internal volume of 230 ml under a nitrogen atmosphere. In addition, 29 ml of methanol were introduced. The autoclave was cooled in an ethanol / dry ice bath, and 12.9 g of methylacetylene having a propadiene concentration of 2 ppm or less (purity: 99.8 mol%, methylacetylene content: 321 mmol, propadiene content: 0.0007 mmol or less) was introduced. Thereafter, it was pressurized with carbon monoxide (CO) and maintained at 1.1 MPa (absolute pressure). The ethanol / dry ice bath was removed, and the autoclave was heated in a 50 ° C. water bath while stirring the mixture in the autoclave, and the temperature of the mixture in the autoclave was adjusted to 50 ° C. After reaching 50 ° C., CO was pressurized to 2.6 MPa (absolute pressure) to initiate the reaction. When the CO partial pressure in the gas phase at the start of the reaction was determined in the same manner as in Example 1, it was 2.1 MPa (absolute pressure).

  In order to maintain the reaction pressure at 2.6 MPa (absolute pressure) for 90 minutes after the start of the reaction, the consumed amount of CO was constantly introduced by a pressure reducing valve. At 90 minutes from the start of the reaction, CO introduction was interrupted, the autoclave was sealed, and the mixture in the autoclave was continuously stirred. The methyl acetylene conversion after 90 minutes from the start of the reaction was found to be 28% from the total amount of CO absorbed up to 90 minutes after the start of the reaction. In the same manner as in Example 1, when the CO partial pressure at the time of 90 minutes from the start of the reaction was determined, it was 2.2 MPa (absolute pressure).

  164 minutes after starting the reaction, the reaction pressure became 1.8 MPa (absolute pressure). The CO partial pressure at the time of 164 minutes after the reaction was started in the same manner as in Example 1 was 1.4 MPa (absolute pressure). The introduction of CO was resumed, and the reaction pressure was maintained at 1.8 MPa (absolute pressure) while stirring was continued from 164 minutes after the start of the reaction to 194 minutes after the start of the reaction. At 194 minutes after the start of the reaction, the introduction of CO was interrupted, the autoclave was sealed, and stirring of the mixture in the autoclave was continued. The methyl acetylene conversion after 194 minutes from the start of the reaction was found to be 61% from the total amount of CO absorbed from the start of the reaction until 194 minutes. When the CO partial pressure at the time of 194 minutes from the start of the reaction was determined in the same manner as in Example 1, it was 1.5 MPa (absolute pressure).

297 minutes after the start of the reaction, the reaction pressure became 1.1 MPa (absolute pressure). The CO partial pressure at the time of 297 minutes after starting the reaction in the same manner as in Example 1 was 0.8 MPa (absolute pressure). The introduction of CO was restarted, and the reaction pressure was maintained at 1.1 MPa (absolute pressure) while continuing stirring for 297 minutes after the start of the reaction to 400 minutes after the start of the reaction, and then cooled. At 400 minutes after the start of the reaction, no CO absorption was observed. The reaction temperature is 50 ° C. for 90 minutes after the start of the reaction, 55 ° C. for 90 minutes to 200 minutes after the start of the reaction, and 200 minutes to 400 after the start of the reaction. The minutes were 65 ° C. When the reaction solution was quantitatively analyzed by gas chromatography (GC), the amount of methyl methacrylate produced was 8.6 × 10 ⁵ mol / Pd mol.

Comparative Example 1
(Preparation of catalyst solution)
A catalyst solution was prepared in the same manner as in Example 1 [Preparation of catalyst solution].

[Production of methyl methacrylate]
1.26 ml fraction of the catalyst solution obtained above (palladium 0.000295 mmol, diphenyl (6-methyl-2-pyridyl) phosphine 0.0177 mmol equivalent) was introduced into a stainless steel autoclave having an internal volume of 230 ml under a nitrogen atmosphere. In addition, 29 ml of methanol were introduced. The autoclave was cooled in an ethanol / dry ice bath and 11.1 g of methylacetylene having a propadiene concentration of 2 ppm or less (purity: 99.8 mol%, methylacetylene content: 276 mmol, propadiene content: 0.0006 mmol or less) was introduced. Thereafter, it was pressurized with carbon monoxide (CO) and maintained at 1.1 MPa (absolute pressure). The ethanol / dry ice bath was removed, and the autoclave was heated in a 50 ° C. water bath while stirring the mixture in the autoclave, and the temperature of the mixture in the autoclave was adjusted to 50 ° C. After reaching 50 ° C., CO was pressurized to 2.6 MPa (absolute pressure) to initiate the reaction. When the partial pressure of CO in the gas phase at the start of the reaction was determined in the same manner as in Example 1, it was 2.2 MPa (absolute pressure). During the reaction, in order to keep the reaction pressure at 2.6 MPa (absolute pressure), the consumed CO was constantly introduced by a pressure reducing valve.

The reaction pressure was maintained at 2.6 MPa (absolute pressure) while continuing stirring for 400 minutes after the start of the reaction, and then cooled. At 400 minutes after the start of the reaction, no CO absorption was observed. The CO partial pressure at 400 minutes after the start of the reaction in the same manner as in Example 1 was determined to be 2.3 MPa (absolute pressure). The reaction temperature is 50 ° C. for 90 minutes after the start of the reaction, 55 ° C. for 90 minutes to 200 minutes after the start of the reaction, and 200 minutes to 400 after the start of the reaction. The minutes were 65 ° C. When the reaction solution was quantitatively analyzed by gas chromatography (GC), the amount of methyl methacrylate produced was 7.4 × 10 ⁵ mol / Pd mol.

Comparative Example 2
(Preparation of catalyst solution)
A catalyst solution was prepared in the same manner as in Example 1 [Preparation of catalyst solution].

[Production of methyl methacrylate]
1.26 ml fraction of the catalyst solution obtained above (palladium 0.000295 mmol, diphenyl (6-methyl-2-pyridyl) phosphine 0.0177 mmol equivalent) was introduced into a stainless steel autoclave having an internal volume of 230 ml under a nitrogen atmosphere. In addition, 29 ml of methanol were introduced. The autoclave was cooled in an ethanol / dry ice bath, and 11.1 g of methylacetylene having a propadiene concentration of 2 ppm or less (purity: 99.9 mol%, methylacetylene content: 277 mmol, propadiene content: 0.0006 mmol or less) was introduced. Thereafter, it was pressurized with carbon monoxide (CO) and maintained at 1.1 MPa (absolute pressure). The ethanol / dry ice bath was removed, and the autoclave was heated in a 50 ° C. water bath while stirring the mixture in the autoclave, and the temperature of the mixture in the autoclave was adjusted to 50 ° C. After reaching 50 ° C., CO was pressurized to 1.8 MPa (absolute pressure) to initiate the reaction. When the CO partial pressure in the gas phase at the start of the reaction was determined in the same manner as in Example 1, it was 1.4 MPa (absolute pressure). During the reaction, in order to keep the reaction pressure at 1.8 MPa (absolute pressure), consumed CO was constantly introduced by a pressure reducing valve.

The reaction pressure was maintained at 1.8 MPa (absolute pressure) while continuing stirring for 400 minutes after starting the reaction, and then cooled. At 400 minutes after the start of the reaction, no CO absorption was observed. The CO partial pressure at 400 minutes after the reaction was started in the same manner as in Example 1 was 1.5 MPa (absolute pressure). The reaction temperature is 50 ° C. for 90 minutes after the start of the reaction, 55 ° C. for 90 minutes to 200 minutes after the start of the reaction, and 200 minutes to 400 after the start of the reaction. The minutes were 65 ° C. When the reaction solution was quantitatively analyzed by gas chromatography (GC), the amount of methyl methacrylate produced was 7.7 × 10 ⁵ mol / Pd mol.

Comparative Example 3
(Preparation of catalyst solution)
A catalyst solution was prepared in the same manner as in Example 1 [Preparation of catalyst solution].

[Production of methyl methacrylate]
1.26 ml fraction of the catalyst solution obtained above (palladium 0.000295 mmol, diphenyl (6-methyl-2-pyridyl) phosphine 0.0177 mmol equivalent) was introduced into a stainless steel autoclave having an internal volume of 230 ml under a nitrogen atmosphere. In addition, 29 ml of methanol were introduced. The autoclave was cooled in an ethanol / dry ice bath, and 11.2 g of methylacetylene having a propadiene concentration of 2 ppm or less (purity: 99.8 mol%, methylacetylene content: 279 mmol, propadiene content: 0.0006 mmol or less) was introduced. Thereafter, it was pressurized with carbon monoxide (CO) and maintained at 0.6 MPa (absolute pressure). The ethanol / dry ice bath was removed, and the autoclave was heated in a 50 ° C. water bath while stirring the mixture in the autoclave, and the temperature of the mixture in the autoclave was adjusted to 50 ° C. After reaching 50 ° C., CO was pressurized to 1.1 MPa (absolute pressure) to initiate the reaction. When the CO partial pressure in the gas phase at the start of the reaction was determined in the same manner as in Example 1, it was 0.6 MPa (absolute pressure). During the reaction, in order to keep the reaction pressure at 1.1 MPa (absolute pressure), consumed CO was constantly introduced by a pressure reducing valve.

The reaction pressure was maintained at 1.1 MPa (absolute pressure) while continuing stirring for 400 minutes from the start of the reaction, and then cooled. At 400 minutes after the start of the reaction, no CO absorption was observed. The CO partial pressure at 400 minutes after the reaction was started in the same manner as in Example 1 was 0.7 MPa (absolute pressure). The reaction temperature is 50 ° C. for 90 minutes after the start of the reaction, 55 ° C. for 90 minutes to 200 minutes after the start of the reaction, and 200 minutes to 400 after the start of the reaction. The minutes were 65 ° C. When the reaction solution was quantitatively analyzed by gas chromatography (GC), the amount of methyl methacrylate produced was 4.6 × 10 ⁵ mol / Pd mol.

  The present invention can be used for the production of methacrylic acid esters, specifically alkyl methacrylates, particularly methyl methacrylate.

Claims (14)

  A method for producing a methacrylate ester comprising reacting a compound having a hydroxyl group and carbon monoxide with methylacetylene in the presence of a catalyst containing a Group 10 metal compound, a protonic acid and a phosphine compound. A method for producing a methacrylic acid ester, wherein the partial pressure is lowered.   The production method according to claim 1, wherein the partial pressure of carbon monoxide is lowered by 0.1 MPa or more.   The production method according to claim 1 or 2, wherein the partial pressure of carbon monoxide at the time of starting to lower the partial pressure of carbon monoxide is 1.0 MPa or more.   The production method according to any one of claims 1 to 3, wherein the conversion rate of methylacetylene is within a range of 1 to 70% at the time when the partial pressure of carbon monoxide starts to be lowered.   The production method according to claim 1, wherein the reaction pressure is lowered during the reaction and the partial pressure of carbon monoxide is lowered.   The production method according to any one of claims 1 to 5, wherein the reaction time at the start of lowering the partial pressure of carbon monoxide is 1 to 300 minutes.   The production method according to claim 1, wherein the catalyst further contains an amine compound.   The production method according to any one of claims 1 to 7, wherein the Group 10 metal compound is a palladium compound.   The production method according to claim 1, wherein the phosphine compound is an aromatic tertiary pyridylphosphine.   The production method according to claim 1, wherein the protonic acid is a sulfonic acid compound.   The production method according to any one of claims 7 to 10, wherein the amine compound is N, N-dimethylaniline.   The manufacturing method in any one of Claims 1-11 which perform the said reaction by a continuous type using n reaction tanks (n represents an integer greater than or equal to 2) connected in series.   The partial pressure of carbon monoxide in the nth reaction vessel located at the most downstream in the flow direction of methylacetylene is lower than the partial pressure of carbon monoxide in the first reaction vessel located at the uppermost stream. Production method.   The production method according to claim 13, wherein the reaction pressure in the nth reaction vessel located at the most downstream in the flow direction of methylacetylene is lower than the reaction pressure in the first reaction vessel located at the most upstream.