Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acid esters
Reexamination Certificate
2000-09-27
2003-03-04
Nazaro-Gonzalez, Porfirio (Department: 1623)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acid esters
C560S243000, C560S245000
Reexamination Certificate
active
06528679
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
This invention relates to a process for producing a phenyl ester in a high yield and stably by allowing benzene, a carboxylic acid and a molecular oxygen to react with each other in the presence of a specific palladium catalyst. It also relates to the specific palladium catalyst used in the process for the production of a phenyl ester.
(2) Description of the Related Art
A process for producing a phenyl ester by allowing benzene, a carboxylic acid and molecular oxygen to react with each other in the presence of a catalyst is well known. Proposals have been made wherein the reaction is conducted in the vapor phase or liquid phase using a noble metal catalyst. Palladium is most popularly used as the main ingredient of the noble catalyst, and some proposals also have been made wherein a co-catalyst comprising a metal, which exhibits by itself no catalytic activity for the specified reaction, is used in combination with the noble catalyst.
As examples of the process using a metal catalyst, there can be mentioned a process using at least one metal selected from palladium and platinum, described in Japanese Examined Patent Publication (hereinafter abbreviated to “JP-B”) S46-33024, a process using a combination of at least one metal selected from palladium and platinum with elemental bismuth or tellurium,: described in JP-B S48-18219. Further, a process using a catalyst comprising a combination of palladium or a palladium compound with at least one compound comprising a metal selected from cadmium, zinc, uranium, tin, lead, antimony, bismuth. tellurium and thallium, and in the presence of nitric acid is described in JP-B S55-15455.
A catalyst system comprising palladium and antimony, and an alkali metal salt as an activation promoter is described in JP-B 56-21463, Japanese Unexamined Patent Publication (hereinafter abbreviated to “JP-A”) S52-27089, JP-A S52-77892 and JP-A S52-130494.
Further, as examples of the process using a metal compound as catalyst, there can be mentioned a process using a catalyst comprising a combination of at least one metal compound selected form an oxide, a hydroxide, an acetate or a nitrate of a metal selected from platinum, palladium, rhodium, ruthenium, iridium or osmium, with at least one alkali metal nitrate (JP-B S50-34544), a process using a combination of (a) at least one member selected from metallic palladium and palladium compounds, with (b) at least one compound selected from nitric acid, nitrous acid and metal salts of these acids, or a combination of (a), (b) with (c) at least one metal salt of a carboxylic acid (JP-A S48-4439, and a process using a combination of palladium acetate with antimony acetate, and at least one metal acetate, the metal of which is selected from chromium, nickel, manganese and iron (JP-B H2-13653).
The processes for allowing benzene, a carboxylic acid and molecular oxygen to react with each other in the liquid phase using a palladium catalyst or a palladium compound catalyst to produce a phenyl ester have a problem such that palladium metal is dissolved in the raw material liquid, and the catalytic activity is reduced with time. Palladium is expensive and thus the above processes are costly. If a step of recovering palladium is conducted, the production processes become complicated. Further, the operation of compensating the decrease of catalytic activity with time is troublesome and not advantageous from an industrial point of view.
In a process using a metal salt catalyst soluble in a reaction liquid, a step of recovering the metal salt must be conducted. Further, a problem arises such that, for example, a palladium salt is used, palladium metal is liable to be deposited on the inner wall of a reactor during the reaction, and this also leads to reduction of catalytic activity with time and loss of palladium.
A process comprising a liquid phase reaction using as a catalyst a combination of palladium with bismuth and/or lead wherein a soluble bismuth compound and/or a soluble lead compound is additionally incorporated in the reaction system is described in JP-A S63-174950. In this process, the soluble bismuth compound and/or the soluble lead compound prevents dissolution of metallic bismuth or lead supported on the palladium catalyst, and thus, dissolution of the main catalyst ingredient, i.e., palladium can be suppressed and the reduction with time of catalytic activity can be minimized. This process has a problem such that the amount of the soluble bismuth compound and/or the soluble lead compound incorporated is large, and the soluble compounds must be recovered as a crystal at the step of separating and purifying a phenyl ester, which leads to complication of the production process.
SUMMARY OF THE INVENTION
In view of the foregoing prior art, an object of the invention is to provide a process for producing a phenyl ester by allowing benzene, a carboxylic acid and molecular oxygen to react with each other in the presence of a palladium catalyst to produce a phenyl ester, whereby a high catalytic activity is maintained and a phenyl ester can be produced under stable conditions.
In accordance with the present invention, there is provided a process for producing a phenyl ester which comprises the step of: allowing benzene, a carboxylic acid and molecular oxygen to react with each other in the presence of a catalyst comprising:
(A) palladium,
(B) at least one element selected from the group consisting of elements of groups 14, 15 and 16 and the fourth to sixth periods of the periodic table, and
(C) at least one element selected from the group consisting of elements of groups 3, 4 and lanthanoid elements of the periodic table.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Palladium (A) and element (B), which is at least one member selected from elements of groups 13, 14, 15 and 16 and the fourth to sixth periods of the periodic table, are used preferably in a metallic state. Palladium (A) and element (B) selected from groups 13, 14, 15 and 16 and the fourth to sixth periods of the periodic table may form together an intermetallic compound.
Element (B) is not particularly limited provided that it is selected from groups 13, 14, 15 and 16 and the fourth to sixth periods of the periodic table. Usually element (B) is selected from those belonging to the fourth to sixth periods. Of these, lead, bismuth, antimony and tellurium are preferable. Among the elements of groups 13, 14, 15 and 16 and the fourth to sixth periods, those of group 16 are preferable. The ratio of element (B) to palladium is usually in the range of 0.01/1 to 20/1 by mol, preferably 0.02/1 to 2/1 by mol. When the ratio of element (B)/Pd is too small or too large, the effect of the invention becomes difficult to obtain.
Element (C), which is at least one element selected from the group consisting of elements of groups 3, 4 and lanthanoid elements of the periodic table, is preferably used in a metal oxide form. A part of element (C) may be in a metal form. Element (C) may form an intermetallic compound together with at least one of palladium (A) and element (B).
When the catalyst of the invention is supported on a carrier which is inactive to the reaction, element (C) selected from groups 3, 4 and lanthanoid elements of the periodic table may form a double oxide together with the carrier. When the catalyst of the invention is used without being supported on a carrier which is inactive to the reaction, at least one of palladium (A) and element (B) may be used in a form of being supported on a metal oxide comprising element (C), i.e., at least one element selected from groups 3, 4 and lanthanoid elements of the periodic table.
Element (C) is not particularly limited provided that it is selected from groups 3, 4 and lanthanoid elements of the periodic table. Usually element (C) is selected from those belonging to the fourth to sixth periods. Of these, yttrium, lanthanoid elements, titanium, zirconium and hafnium are preferable. Cerium, praseodymium, neodymium, titanium, zirconium and hafnium are especial
Asakawa Tetsuo
Doi Takao
Miyake Takanori
Mori Yoshihiko
Auerbach Jeffrey I.
Deemie Robert W.
Liniak Berenato & White
Nazaro-Gonzalez Porfirio
Tosoh Corporation
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