Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Inorganic carbon containing
Reexamination Certificate
2002-03-20
2004-08-31
Bell, Mark L. (Department: 1755)
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Inorganic carbon containing
C502S212000, C502S232000, C502S240000, C502S305000, C502S306000, C502S308000, C502S311000, C502S313000, C502S317000, C502S319000, C502S321000, C502S527140, C502S527170, C502S527240, C428S364000, C428S372000, C562S537000, C562S538000, C562S546000, C562S471000, C562S479000, C562S532000, C562S599000
Reexamination Certificate
active
06784134
ABSTRACT:
TECHNICAL FIELD TO WHICH THE INVENTION BELONGS
This invention relates to catalyst for preparation of unsaturated aldehyde and unsaturated carboxylic acid. More particularly, the invention relates to a catalyst which is suitable for use in production of methacrolein and methacrylic acid, or acrolein and acrylic acid, by vapor-phase catalytic oxidation of isobutylene, tertiary butanol (which hereafter may be identified as t-butanol) or propylene. The invention also relates to processes for producing these unsaturated aldehydes and unsaturated carboxylic acids, using said catalyst.
PRIOR ART
Many proposals have been made for catalysts to be used in the occasion of vapor-phase catalytic oxidation of isobutylene, t-butanol or propylene to produce respectively corresponding unsaturated aldehyde and unsaturated carboxylic acid.
It is already known that the yield improves when the catalyst shape is changed from pellets to rings. For example, JP 59 (1984)-46132 A (=U.S. Pat. No. 4,511,671 A, EP 102,641 A1) has disclosed, as merits of adopting a specific ring form: (1) conversion improves due to increase in geometrical surface area, (2) yield improves because the reduced catalyst wall thickness enhances heat-removing effect, (3) pressure loss decreases, and (4) catalyst life is extended due to decrease in thermal load. For still increasing these effects, thinning the ring thickness is preferred. Reduction in the thickness, however, invites decrease in mechanical strength and causes such problems as, for example, when finished ring-formed catalyst is kept in a drum can, the catalyst at the bottom of the can break and become useless, or they may break when they are charged in reaction tubes and scattering in pressure loss among the reaction tubes increases.
As a method for improving strength of catalysts, it is known to add a fibrous material. For example, JP 51(1976)-20357 B relating to vanadium pentoxide catalyst, copper-chromic acid catalyst, nickel-diatomaceous earth catalyst and manganese-chromic acid catalyst, discloses a method of adding a fibrous material, for example, blue asbestos, to the catalyst powder obtained through drying or calcination and subsequent pulverization. However, effect of adding a fibrous material to catalysts comprising molybdenum and bismuth as the essential ingredients is unknown. Also as to ring-formed catalyst, addition of fibrous material gives rise to a problem of increased scattering in mechanical strength among individual catalyst rings, while their mechanical strength can be improved.
JP 59 (1984)-183832 A (=U.S. Pat. No. 4,564,607 A) discloses a method of using whiskers having an average diameter not more than 5&mgr;m as a reinforcement, in preparation of heteropolyacid-based catalyst. Whereas, as to catalyst comprising molybdenum and bismuth as the essential ingredients, addition of whiskers results in yield reduction, while improving catalyst strength.
JP 6 (1994)-381 A (=U.S. Pat. No. 5,532,199 A, EP 574,895 A1) discloses a method of using inorganic fibers having an average diameter of 2-200&mgr;m as assistant carrier, in preparing carried catalyst containing molybdenum and bismuth as essential ingredients. This method aims at preparation of carried catalyst in which the carrier carries a large amount of the catalyst, and for that purpose a method of preparation must be such that a slurry formed by dispersing catalytically active ingredients and inorganic fibers in a liquid is deposited on a carrier and at the same time the liquid is vaporized and evaporated. This preparation method, however, is not necessarily easy of operating, and the catalytic activity varies depending on variation in preparation conditions. Hence, there is a problem of difficulty in preparing catalyst which exhibits uniform catalytic performance.
PROBLEMS TO BE SOLVED BY THE INVENTION
Accordingly, therefore, the object of the present invention is to solve the above problems in the prior art, by providing a catalyst suitable for catalytic vapor-phase oxidation of isobutylene, t-butanol or propylene to produce corresponding unsaturated aldehyde and unsaturated carboxylic acid, i.e., a catalyst which excels in mechanical strength, is capable of providing the object products at high yield, and shows little deterioration in catalytic performance with time.
MEANS TO SOLVE THE PROBLEMS
Through our research work we have come to find that a catalyst for production of unsaturated aldehyde and unsaturated carboxylic acid, which is obtained by shaping a catalyst composition containing as active ingredients at least molybdenum and bismuth into rings and which additionally contains in the catalyst composition inorganic fibers such as glass fiber, alumina fiber, silica fiber, carbon fiber and the like, can accomplish the above object. The present invention is completed based on the above knowledge.
Thus, according to the invention, a catalyst for production of unsaturated aldehyde and unsaturated carboxylic acid is provided, which is characterized in that it consists of ring-shaped bodies comprising a catalytic composition containing as active ingredients at least molybdenum and bismuth, and inorganic fibers.
According to the invention, furthermore, a process is provided, which is characterized by using the above catalyst in catalytic vapor-phase oxidation of isobutylene, tertiary butanol or propylene with molecular oxygen, whereby producing respectively corresponding methacrolein and methacrylic acid or acrolein and acrylic acid.
The reason why the addition of inorganic fibers according to the present invention achieves improvements not only in the catalyst's mechanical strength but also in the catalytic performance, as well as inhibition of catalyst's deterioration with time is not fully clear yet. Presumably, because the catalyst composition is diluted with the inorganic fibers, the heat generated during the reaction is dispersed, sequential reactions are inhibited, and thermal degradation of the catalyst is inhibited. Also in view of the observation that the improvement in the catalyst's mechanical strength is achieved when the added inorganic fibers have a specific size, it is presumed that the inorganic fibers are adequately dispersed in the catalyst to maintain an adequately mixed and contacted condition with the catalyst composition.
EMBODIMENTS OF THE INVENTION
The catalyst of the present invention is of the type normally referred to as shaped catalyst, which is in the form of ring-shaped catalyst made of a catalyst composition containing molybdenum and bismuth as essential ingredients, and inorganic fibers. It is not a so called carried catalyst, formed by carrying a catalyst composition on a carrier.
As typical examples of the catalyst composition, those expressed by the following general formula (1) may be named:
MO
a
Bi
b
Fe
c
A
d
B
e
O
x
(1)
(in which Mo is molybdenum; Bi is bismuth; Fe is iron; A is at least one element selected among nickel and cobalt; B is at least an element selected among alkali metal elements, alkaline earth metal elements, thallium, phosphorus, tellurium, antimony, tin, cerium, lead, niobium, manganese, arsenic, zinc, silicon, aluminium, titanium, zirconium and tungsten; O is oxygen; a, b, c, d, e and x stand for the respective atomic numbers of Mo, Bi, Fe, A, B and O, where a is 12, b is 0.1-10, c is 0.1-20, d is 2-20; e is 0-30 and x is a numerical value determined by the extents of oxidation of the other elements).
The catalyst composition expressed by the general formula (1) can be formulated following those methods generally used for preparing this type of catalyst. As the starting materials of each of the ingredients, oxides of the ingredients or salts of the ingredients which form oxides under heating, such as nitrates, ammonium salts, organic acid salts, carbonates, alkali metal salts and the like, may be suitably selected for use.
As inorganic fibers, glass fibers, ceramic fibers, carbon fibers and the like may be used, of those, glass fibers, alumina fibers and silica fibers are preferred. In p
Kasuga Hiroto
Shiraishi Eiichi
Bell Mark L.
Hailey Patricia L.
Nippon Shokubai Co. , Ltd.
Sherman & Shalloway
LandOfFree
Catalyst for preparation of unsaturated aldehyde and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Catalyst for preparation of unsaturated aldehyde and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Catalyst for preparation of unsaturated aldehyde and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3324178