Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acids and salts thereof
Reexamination Certificate
2001-06-22
2003-10-14
Nazario-Gonzalez, Porfirio (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acids and salts thereof
C502S060000, C502S066000, C502S074000, C540S485000, C540S534000, C540S538000, C562S577000
Reexamination Certificate
active
06632964
ABSTRACT:
TECHNICAL FIELD
This invention relates to a process for producing an aliphatic aldehyde-acid, particularly adipaldehyde-acid (5-formylpentanoic acid), and/or an aliphatic dicarboxylic acid, particularly adipic acid, by oxidation of a cyclic ketone and a catalyst useful for producing them. More particularly, the invention relates to a catalyst which comprises a carrier having fixed thereon a metal element belonging to the groups 4 to 11 of the Periodic Table, e.g., iron, and possesses specific properties (hereinafter referred to as a fixed catalyst or simply a catalyst) and a process of producing adipaldehyde-acid and/or adipic acid which comprises oxidizing a cyclic ketone, e.g., cyclohexanonone, in the presence of the catalyst. The invention also provides a process of leading adipaldehyde-acid to e-caprolactam.
BACKGROUND ART
Adipaldehyde-acid is a useful compound as an intermediate of syntheses. Known processes for production include, for example, oxidation of cyclohexanone with molecular oxygen in the presence of water and a copper compound (JP-B-47-26768, the term “JP-B” as used herein means an “examined Japanese patent publication) and oxidation of cyclohexanone with molecular oxygen in the presence of water and an iron or iridium compound soluble in the reaction system (JP-B-4-2583).
Because the catalyst used in these processes is an iron, iridium or copper compound that is soluble in a liquid phase, application of the processes to industrial scale production involves the following three problems. Firstly, where an iron-containing homogeneous catalyst is used in an oxidative reaction system of cyclohexanone with oxygen for a long time, iron atoms gather via an oxygen atom to form inert iron hydroxide, basic iron hydroxide, iron oxide, etc. so that the activity decreases with time. Secondly, a copper- or iridium-containing homogeneous catalyst has poor productivity due to a low reaction rate. Thirdly, where a compound made of the metal and a halogen as a counter ion, which generally exhibits high activity, is used as a catalyst, the existence of halogen in the system essentially requires that the equipment, such as a reactor, piping, etc., be made of a highly anti-corrosive material, which results in, of necessity, an increase of production cost.
DISCLOSURE OF THE INVENTION
The inventors of the present invention have conducted extensive investigation in order to solve the above-described problems. They have found as a result that a composite comprising a carrier having supported thereon a metal element belonging to the groups 4 to 11 of the Periodic Table, for example, iron and having specific acidity exhibits stable activity in the reaction for producing an aliphatic aldehyde-acid and/or an aliphatic dicarboxylic acid by oxidation of a cyclic ketone in a heterogeneous reaction system in the co-presence of molecular oxygen, particularly oxidation reaction of cyclohexanone to produce adipaldehyde-acid and/or adipic acid.
The present invention provides a novel process of producing an aliphatic aldehyde-acid and/or an aliphatic adipic acid by oxidation of a cyclic ketone, especially of producing adipaldehyde-acid and/or adipic acid by oxidation of cyclohexanone. The gist of the present invention consists in a process of producing an aliphatic aldehyde-acid and/or an aliphatic dicarboxylic acid characterized in that a cyclic ketone is oxidized with molecular oxygen in the presence of a fixed catalyst which comprises a composite of a carrier and at least one metal element belonging to the groups 4 to 11 of the Periodic Table supported on the carrier and has an acid amount of 0.06 mmol/g or more per unit weight of the carrier.
The present invention also relates to a catalyst for producing an aliphatic aldehyde-acid and/or an aliphatic dicarboxylic acid by oxidizing a cyclic ketone, especially adipaldehyde-acid and/or adipic acid by oxidizing cyclohexanone. The gist of this aspect of the invention lies in a fixed catalyst characterized by comprising a composite of a carrier and at least one metal element belonging to the groups 4 to 11 of the Periodic Table supported on the carrier and having an acid amount of 0.06 mmol/g or more per unit weight of the carrier.
The gist of the invention also resides in a process for producing e-caprolactam which comprises oxidizing cyclohexanone with molecular oxygen in the presence of a fixed catalyst comprising a composite of a carrier and at least one metal element belonging to the groups 4 to 11 of the Periodic Table supported on the carrier and having an acid amount of 0.06 mmol/g or more per unit weight of the carrier to produce an oxidation product containing adipaldehyde-acid, allowing the adipaldehyde-acid recovered from the oxidation product to react with ammonia and hydrogen in the presence of a hydrogenating catalyst to produce 6-aminocaproic acid, and heating the resulting 6-aminocaproic acid to cause cyclization into e-caprolactam.
Preferred embodiments of the present invention provide the above-described fixed catalyst wherein the metal element belonging to the groups 4 to 11 of the Periodic Table, which is supported on the carrier, is selected from iron, copper, and iridium, particularly an iron complex; and a process of producing an aliphatic aldehyde-acid and/or an aliphatic dicarboxylic acid, especially adipaldehyde-acid and/or adipic acid, which comprises oxidation in the presence of this catalyst and water.
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention will be described in detail.
Carriers that can be used in the present invention include clay, ion-exchange resins, and metal oxides. Zeolite is preferably used. While zeolite to be used is not particularly limited in crystal structure, zeolites having channels greater than a 8-membered oxygen ring in at least one direction are preferred as channels constituting zeolile structures. Still preferred are those having channels of the above-specified condition in two or more directions, particularly three or more directions. Specifically, examples of preferred skeleton structure types are, according to the classification advised by IZA (International Zeolite Association), FAU, ERI, FER, BEA, MOR, MWW, MTW, MFI, and MEL.
In the fixed catalyst used in the reaction it is important for the carrier to have solid acidic properties. It is necessary for zeolite, for instance, to contain at least one M element selected from the group consisting of aluminum, gallium, indium, boron, etc. and at least one T element selected from the group consisting of silicon, germanium, tin, etc. in addition to oxygen as elements which constitute the zeolite skeleton. Aluminum is preferred as an M element, and silicon is preferred as a T element. A zeolite skeleton may comprise two or more kinds of the M elements and two or more kinds of the T elements. A zeolite skeleton may further comprise iron, titanium, zinc, manganese, chromium, cobalt, vanadium and zirconium. The molar ratio of these elements as represented by 2T/M (a value obtained by dividing the total mole number of T elements by a half of the total mole number of M elements) is preferably 9 or greater before supporting at least one metal element belonging to the groups 4 to 11 of the Periodic Table and is preferably 8 or greater after the supporting, and is preferably not greater than 300 either before or after the supporting.
It is preferred for zeolite as a carrier to have a specific surface area of 50 to 1500 m
2
/g, particularly 100 to 1300 m
2
/g, especially 150 to 1200 m
2
/g.
Zeolite having too small a mean particle diameter has poor separability. One having too large a mean particle diameter has a reduced outer surface area, which makes the diffusion of the reaction substrate, the desired reaction product, etc. highly rate-determining. For these reasons, the mean particle diameter is desirably 0.01 &mgr;m to 10 &mgr;m, more desirably 0.02 &mgr;m to 8 &mgr;m, most desirably 0.03 &mgr;m to 6 &mgr;m. The term “mean particle diameter” refers to a number average of diameters of circles having the same areas as projected areas o
Fujii Masaru
Setoyama Tohru
Mitsubishi Chemical Corporation
Nazario-Gonzalez Porfirio
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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