Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Phosphorus or compound containing same
Reexamination Certificate
2003-03-13
2004-11-02
Bell, Mark L. (Department: 1755)
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Phosphorus or compound containing same
C502S209000, C502S210000, C502S211000, C502S212000, C502S213000
Reexamination Certificate
active
06812188
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a catalyst for producing methacrylic acid by the vapor-phase catalytic oxidation of methacrolein that has a long life, a high activity and a high selectivity; and the method for manufacturing the catalyst.
BACKGROUND ART
For the production of methacrylic acid by vapor-phase catalytic oxidation of methacrolein, there have been proposed lots of catalysts, most of which contain molybdenum and phosphorus as the main components and have a structure of heteropolyacid and/or the salt thereof. However, they have a low reactivity, a low selection for the object material, and a short life in comparison with the molybdenum-vanadium catalyst proposed for producing acrylic acid by the oxidation of acrolein which is known to be similar to the vapor-phase catalytic oxidation of methacrolein. The proposed catalysts are demanded to improve in catalytic ability though some of them are industrialized.
The present inventors having been trying to improve a low reactive, low selective and short-life catalyst for vapor-phase catalytic oxidation of methacrolein, and found out the catalyst which has high reactivity, high selectivity and good stability in life containing the various elements in addition to Mo, V and P and having a structure of heteropolyacid (or the salt thereof). As a result, there have been proposed the catalysts as described in JP No.11416/1883, JP No.24140/1884, JP No.14535/1987 and JP No.30177/1987.
The catalyst, if packed in a fixed bed reaction vessel for industrial use, has to be molded into a specified size in order to reduce the loss in gas pressure in the catalyst layer. So, it is known that the catalyst powder is generally molded into a pellet, a tablet, a ring and a sphere, or the catalytically active materials are impregnated into or coated on an inactive carrier.
The coated catalyst having the inactive carrier as the core includes the following merits:
(1) The effective utility of the catalytically active component increases.
(2) The improvement in the selectivity can be expected because the staying-time distribution of reaction materials within the catalyst becomes uniform.
(3) An increased thermal conductivity of the catalyst or a dilution effect by an inactive carrier makes it easy to remove the reaction heat.
So, the coated catalyst is often applied to a highly exothermal selective oxidation reaction.
On the other hand, the technical difficulties for producing the coated catalyst are as follows:
(1) It is difficult to produce a mechanically strong catalyst because the coat layer is liable to peel or crack.
(2) It is difficult to coat the inactive carrier with a large amount of catalytically active material.
(3) The inclusion of inactive material makes it difficult to prepare a highly active catalyst.
There has been no general technique to solve such problems because of the diversity in property among catalytically active materials. Practically in this state, the problems are solved individually depending on the catalysts.
An object of the present invention is to provide a catalyst for producing methacrylic acid by vapor-phase catalytic oxidation of methacrolein at a high yield and with a high selectivity; and a method for producing thereof.
DISCLOSURE OF THE INVENTION
In order to solve the above problem, the present inventors have tried to improve a conventional low reactive, low selective and short-life catalyst for vapor-phase catalytic oxidation of methacrolein, and found out the catalyst having high reactivity, high selectivity, good stability in life and high performance suitable for an industrial use, when preparing the catalyst i.e. a heteropolyacid and/or the salt thereof containing Mo, V, P and Cu as the indispensable active components and to which copper acetate is added as the cu component. This finding has completed the present invention. Namely the present invention is as follows:
(1) A catalyst for producing methacrylic acid by the vapor-phase catalytic oxidation of methacrolein, wherein copper acetate is used for all or a part of the necessary amount of a Cu material for preparation of the catalyst comprising Mo, V, P and Cu as the indispensable active components.
(2) A catalyst according to the above term (1), wherein all or a part of said copper acetate is a solid copper acetate to mix and not an aqueous solution.
(3) A catalyst according to the above term (2), wherein said catalyst is a mixture of solid copper acetate with a dried product of a slurry containing Mo, V and P.
(4) A catalyst according to any of the above term (1)-(3), further comprising As as the active component.
(5) A catalyst according to any of the above term (1)-(3), wherein the composition of said active components is represented by the following Formula (1),
Mo
10
V
a
P
b
Cu
c
As
d
X
e
Y
f
O
g
(1)
(wherein, Mo, V, P, Cu, As and O represent molybdenum, vanadium, phosphorus, copper, arsenic and oxygen respectively; X represents at least one element selected from the group consisting of Ag, Mg, Zn, Al, B, Ge, Sn, Pb, Ti, Zr, Sb, Cr, Re, Bi, W, Fe, Co, Ni, Ce and Th; Y represents at least one element selected from the group consisting of K, Rb and Cs; a, b, c, d, e, f and g represent atomic ratios of the respective elements, with 0.1≦a≦6, 0.5≦b≦6, 0<c≦3, 0≦d≦3, 0≦f≦1; g is the ratio determined by the valence and ratio of the other elements than oxygen)
(6) A catalyst according to the above term (5), further comprising As as the active component.
(7) A method for manufacturing a coated catalyst for producing methacrylic acid by the vapor-phase catalytic oxidation of methacrolein, comprising:
(a) a process for mixing copper acetate and compounds containing one or more of Mo, V and P with water to prepare their aqueous solution or their water-based dispersion (hereinafter referred to as the slurry, including the solution and the dispersion);
(b) a process for drying the slurry prepared in the process (a) to obtain a dried slurry;
(c) a process for coating the dried slurry obtained in the process (b) on a carrier with a binder to obtain a coated product; and
(d) a process for calcining the coated product obtained in the process (c),
wherein said binder is at least one selected from the group consisting of water and an organic compound whose boiling point is 150° C. or lower at 1 atm.
(8) A method for manufacturing a coated catalyst for producing methacrylic acid by the vapor-phase catalytic oxidation of methacrolein, comprising:
(a) a process for mixing compounds containing one or more of Mo, V and P with water to prepare their aqueous solution or their water-based dispersion (hereinafter referred to as the slurry, including the solution and the dispersion);
(b) a process for drying the slurry prepared in the process (a) to obtain a dried slurry;
(b′) a process for mixing solid copper acetate with the dried slurry obtained in the process (b) to prepare a mixture;
(c) a process for coating the mixture prepared in the process (b′) on a carrier with a binder to obtain a coated product; and
(d) a process for calcining the coated product obtained in the process (c),
wherein said binder is at least one selected from the group consisting of water and an organic compound whose boiling point is 150° C. or lower at 1 atm.
(9) A method for manufacturing a coated catalyst according to the above term (7) or (8), further using a compound containing As used to mix as the raw material to prepare the slurry in the process (a).
(10) A method for manufacturing a coated catalyst according to the above term (7) or (8), further using copper oxide used to mix as the raw material to prepare the slurry in the process (a).
(11) A method for manufacturing a coated catalyst according to the above term (7) or (8), further using a compound containing As and copper oxide used to mix as the raw material to prepare the slurry in the process (a).
(12) A method for manufacturing a coated catalyst according to any of the above term (7)-(11), wherein said binder is ethanol.
(13) A method for manufacturing a coated catal
Seo Yoshimasa
Sudo Atsushi
Sugi Hideki
Bell Mark L.
Hailey Patricia L.
Nields & Lemack
Nippon Kayaku Kabushiki Kaisha
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