Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Metal – metal oxide or metal hydroxide
Reexamination Certificate
2000-05-22
2002-05-07
Bell, Mark L. (Department: 1755)
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Metal, metal oxide or metal hydroxide
C502S302000, C502S305000, C502S308000, C502S311000, C502S313000, C502S317000, C502S321000, C502S325000, C502S330000, C502S341000, C502S344000, C502S349000, C502S353000, C502S355000, C502S208000, C502S209000, C502S212000, C502S213000
Reexamination Certificate
active
06383973
ABSTRACT:
TECHNICAL FIELD TO WHICH THE INVENTION BELONGS
This invention relates to complex oxide catalysts and process for producing (meth)acrolein and (meth)acrylic acid. More particularly, the invention relates to Mo-Bi-containing complex oxide catalysts which are suitable for use in production of (meth)acrolein and (meth)acrylic acid, and process for producing (meth)acrolein and (meth)acrylic acid by vapor-phase oxidation of at least one compound selected from propylene, isobutylene, t-butanol and methyl-t-butyl ether, in presence of one of said catalysts.
CONVENTIONAL TECHNOLOGY
Many proposals have been made for improved catalysts for vapor phase catalytic oxidation of propylene, isobutylene and the like to produce (meth)acrylic acid and (meth)acrolein. For example, Official Gazette of Sho 50 (1975)-13308A1-JP and Sho 50-47915A1-JP proposed catalysts containing at least an element selected from K, Rb and Cs as one of the essential components, besides Mo, Bi, Fe, Sb and Ni, and Sho 64 (1989)-56634A1-JP proposed those containing at least an element selected from Ni and Co as the essential component, in addition to Mo, Bi and Fe. Also Sho 56 (1981)-52013B1-JP disclosed catalysts containing at least an element selected from Mg, Ca, Zn, Cd and Ba as the essential component, besides Mo, Bi and Fe; and Sho 56-23969B1-JP, catalysts containing at least an element selected from IIA and IIB Group elements as the essential component, besides Mo, Bi and Fe.
In those prior art catalysts, as Bi-supplying source water-soluble compounds thereof, in particular, nitric acid salts are used. However, use of bismuth nitrate as the Bi-supplying source in production of the catalysts of high Bi content (e.g., those in which the atomic ratio of Mo to Bi is, where Mo is 12, Bi is 3-7) is problematical. With the view to solve that problem, Sho 62 (1987)-234548A1-JP has proposed a production method of complex oxide catalysts for which bismuth oxide or bismuth oxycarbonate are used as the Bi-supplying source.
OBJECTS OF THE INVENTION
While prior art Mo-Bi-containing complex oxide catalysts are considered to have overcome the problem incidental to the use of bismuth nitrate, there still remain shortcomings which must be improved. More specifically, for example, {circle around (1+L )} in the occasions of producing (meth)acrolein and (meth)acrylic acid by vapor-phase oxidation of propylene, isobutylene and the like using those catalysts, yield of the object products is not necessarily satisfactory, and {circle around (2+L )} due to sublimation of the molybdenum component in the catalysts during the vapor-phase oxidation reaction of propylene, isobutylene and the like, the catalytic activity decreases and the catalysts are unsatisfactory in respect of their life.
One of the objects of the present invention is, therefore, to provide complex oxide catalysts for production of (meth)acrolein and (meth)acrylic acid, which excel in activity, selectivity and catalyst life and exhibit stable performance over prolonged period.
Another object of the invention is to provide a process for producing (meth)acrolein and (meth)acrylic acid at high yield and with stability, by vapor-phase oxidation of at least one compound selected from propylene, isobutylene, t-butanol and methyl-t-butyl ether with molecular oxygen or a molecular oxygen-containing gas in the presence of the above complex oxide catalyst.
MEANS TO SOLVE THE PROBLEM
We have made concentrative studies on complex oxide catalysts to discover that the amount of molybdenum sublimation during vapor phase oxidation reaction of propylene, isobutylene and the like is inhibited when the amounts of bismuth, iron, cobalt and nickel are relatively large. However, it is also discovered that the relatively large amounts of bismuth, iron, cobalt and nickel increase also the amount of nitrate anions at the time of catalyst preparation, which has such adverse effects as deteriorating moldability of catalyst compositions and impairing their catalytic performance. We continued further investigations with the view to solve this problem, to find that the catalysts excelling in activity, selectivity and life can be produced with good reproducibility by reducing the molar ratio of nitrate anions to molybdenum at the time of the catalyst preparation.
Thus, according to the present invention, complex oxide catalysts are provided, which are represented by general formula (1) below:
Mo
a
W
b
Bi
c
Fe
d
A
e
B
f
C
g
D
h
E
i
O
x
(1)
(wherein Mo is molybdenum; W is tungsten; Bi is bismuth; Fe is iron; A is at least an element selected from nickel and cobalt; B is at least an element selected from sodium, potassium, rubidium, cesium and thallium; C is at least an element selected from alkaline earth metals; D is at least an element selected from phosphorus, tellurium, antimony, tin, cerium, lead, niobium, manganese, arsenic, boron and zinc; E is at least an element selected from silicon, aluminum, titanium and zirconium; and O is oxygen; a, b, c, d, e, f, g, h, i and x denote the atomic ratios of Mo, W, Bi, Fe, A, B, C, D, E and O, respectively; and
where a is 12, 0≦b≦10, 0<c≦10 (preferably 0.1≦c≦10), 0<d≦10 (preferably 0≦d≦10, 2≦e≦15, 0<f≦10 (preferably 0.001≦f≦10), 0≦g≦10, 0≦h≦4 and 0≦i≦30, and x is determined by degree of oxidation of each of the elements),
said catalysts being characterized in that the molar ratio of total nitrate anions to molybdenum at the time of catalyst preparation is adjusted to be more than 1 but not more than 1.8.
According to the invention, furthermore, there is provided a process for producing (meth)acrolein and (meth)acrylic acid through vapor-phase oxidation of at least one compound selected from the group consisting of propylene, isobutylene, t-butanol and methyl-t-butyl ether with molecular oxygen or a molecular oxygen-containing gas, in the presence of an oxidation catalyst, the process being characterized in that it uses an above-defined complex oxide catalyst.
EMBODIMENTS IF THE INVENTION
The catalysts of the present invention are complex oxide catalysts, at the time of whose preparation the ratio of the total molar amount of nitrate anions [NO
3
] to the molar amount of molybdenum [Mo] is adjusted to be more than 1 but not more than 1.8, i.e., 1<[NO
3
]/[Mo]≦1.8. Preferably the ratio is within the range of 1.1≦[NO
3
]/[Mo]≦1.8.
“Total molar amount of nitrate anions at the time of the catalyst preparation” signifies the sum of the molar amount of nitrate anions contained in all of the starting materials which are used for preparation of the catalyst plus the molar amount of nitrate anions originating from the nitric acid which is used for the catalyst preparation as necessity arises. For example, referring to the later appearing Example 1, it is the total sum of the molar amount of nitrate anions derived from the cobalt nitrate, nickel nitrate, etc., which were used as the starting materials, plus the molar amount of the nitrate anions derived from the nitric acid which was used for dissolving bismuth nitrate.
When the ratio of [NO
3
] to [Mo] exceeds 1.8, deterioration in moldability and degradation in the catalytic performance result, and the objects of the present invention cannot be accomplished. That is, when such a large amount of nitrate anions is present at the time of the catalyst preparation, pH becomes very low and under the strongly acidic condition, stability and reactivity of molybdenum, tungsten and the like are adversely affected. Furthermore, because the powder obtained through such steps as evaporation to dry solid, drying and grinding contains the large amount of nitrate anions, it absorbs moisture during molding and is apt to invite deterioration in moldability. Whereas, when the ratio of [NO
3
] to [Mo] is 1 or less, reactivity among the used elements drops, which results in reduction in catalytic activity.
For controlling the ratio of the total molar amou
Kimura Naomasa
Onodera Hideo
Tanimoto Michio
Bell Mark L.
Hailey Patricia L.
Nippon Shokusai Co. Ltd.
LandOfFree
Complex oxide catalysts and process for producing (meth)... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Complex oxide catalysts and process for producing (meth)..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Complex oxide catalysts and process for producing (meth)... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2843493