Catalyst for producing unsaturated nitrile

Details Catalyst for producing unsaturated nitrile Catalyst for producing unsaturated nitrile

2000-10-18

2002-11-12

Langel, Wayne A. (Department: 1754)

Organic compounds -- part of the class 532-570 series

Organic compounds

Nitriles

C558S322000, C558S323000, C558S324000, C502S205000, C502S209000, C502S210000, C502S211000, C502S212000, C502S215000, C502S241000, C502S242000, C502S243000, C502S303000, C502S304000, C502S305000, C502S306000, C502S307000, C502S308000, C502S311000, C502S312000, C502S313000, C502S314000, C502S315000, C502S316000, C502S317000, C502S319000, C502S320000

Reexamination Certificate

active

06479691

ABSTRACT:

TECHNICAL FIELD
The present invention relates to a metal oxide catalyst used in production of unsaturated nitriles by ammoxidation.
PRIOR ART
Hitherto, various compositions of catalysts have been disclosed as catalysts suitable for production of unsaturated nitriles by ammoxidation, for example, production of acrylonitrile by ammoxidation of propylene, production of methacrylonitrile by ammoxidation of isobutylene or tertiary buthanol, etc. For example, U.S. Pat. No. 3,226,422 discloses oxide catalysts containing molybdenum, bismuth and iron, and JP-B-38-19111 discloses oxide catalysts containing iron and antimony. Thereafter, improvement of the catalysts have been intensively attempted, and, for example, U.S. Pat. No. 4,290,922 discloses oxide catalysts containing molybdenum, cobalt, nickel, bismuth, vanadium, calcium and potassium as essential components and zirconium and/or chromium as optional components, Japanese Pat. No. 2640356 discloses oxide catalysts containing molybdenum, bismuth, iron, nickel and an alkali metal element, U.S. Pat. Nos. 5,093,299 and 5,175,334 disclose oxide catalysts containing molybdenum, bismuth, iron, nickel, magnesium, potassium and cesium, JP-A-7-47272 discloses oxide catalysts containing at least one element selected from the group consisting of molybdenum, bismuth, iron, nickel, chromium and indium and an alkali metal element such as potassium as essential components and at least one element selected from the group consisting of manganese, magnesium, zinc, cerium, sodium and phosphorus as optional components, JP-A-7-328441 discloses oxide catalysts containing molybdenum, bismuth, cerium, iron, nickel and magnesium or zinc, and an alkali metal, U.S. Pat. No. 5,132,269 discloses oxide catalysts containing iron, antimony, molybdenum and bismuth or tellurium, and potassium.
These catalysts of the prior art have some effects for improvement in the yield of unsaturated nitrites, but the improvement is still insufficient. In this technical field, it has been desired that yield of unsaturated nitrites is further increased and, besides, combustion of ammonia which often occurs in the case of using catalysts higher in molybdenum content is inhibited to reduce production of by-products such as nitrogen oxide which causes problems in the protection of environment.
DISCLOSURE OF THE INVENTION
As a result of intensive research conducted by the inventors in an attempt to solve the above problems in the prior art, it has been found that in the catalysts containing molybdenum, bismuth, iron, antimony, etc., coexistence of chromium and at least one element selected from the group consisting of zirconium, lanthanum and cerium results in high yields of unsaturated nitrites which cannot be attained with addition of the elements each alone.
These additive elements give synergistically favorable effects. Titanium and hafnium which belong to the same group as zirconium did not show such effects. Rare earth metal elements of the lanthanum group other than lanthanum and cerium also did not show such special effects.
Chromium and at least one element selected from the group consisting of zirconium, lanthanum and cerium show clear effects with addition of them in relatively small amounts, and addition in excess amount rather causes sharp reduction of the yield of the desired products. Furthermore, in the addition of them, the lower proportion of zirconium, lanthanum and cerium to chromium is preferred, and increase of the proportion results in increase of ammonia combustion and reduction of the yield of the desired products. By using in combination chromium and at least one element selected from the group consisting of zirconium, lanthanum and cerium and by finding the preferred relation in the amounts of them in addition, yield of the desired products can be improved and, besides, combustion of ammonia can be inhibited and yield of by-products can be reduced.
That is, the present invention provides a catalyst composition represented by the following empirical formula which is used in production of unsaturated nitriles by ammoxidation.
Mo
10
Bi
a
Fe
b
Sb
c
Ni
d
Cr
e
F
f
G
g
H
h
K
k
X
x
Y
y
O
i
(SiO
2
)
j
In the above formula, Mo, Bi, Fe, Sb, Ni, Cr and K represent molybdenum, bismuth, iron, antimony, nickel, chromium and potassium, respectively, F represents at least one element selected from the group consisting of zirconium, lanthanum and cerium, G represents at least one element selected from the group consisting of magnesium, cobalt, manganese and zinc, H represents at least one element selected from the group consisting of vanadium, niobium, tantalum and tungsten, X represents at least one element selected from the group consisting of phosphorus, boron and tellurium, Y represents at least one element selected from the group consisting of lithium, sodium, rubidium and cesium, O represents oxygen and SiO
2
represents silica, the suffixes a, b, c, d, e, f, g, h, i, j, k, x and y represent a ratio of atoms or atomic groups, and in the case of Mo=10, a=0.1, b=0.3-15, c=0-20, d=3-8, e=0.2-2, f=0.05-1, e/f>1, g=0-5, h=0-3, k=0.1-1, x=0-3, y=0-1, number of oxygen produced by bonding of the above respective components, and j=0-100.
On the other hand, efforts have been made for increasing yield of the desired oxidation products by improving preparation method of catalysts. For example, U.S. Pat. No. 3,350,323 discloses a method of adding an aqueous bismuth citrate solution to an aqueous molybdic acid solution, JP-A-53-10387, JP-A-53-10388 and U.S. Pat. No. 3,847,831 disclose methods of adding a bismuth compound in solid state to an aqueous molybdic acid solution, U.S. Pat. No. 4,418,007 discloses a method of simultaneously adding an aqueous solution of a bismuth salt and aqueous ammonia to an aqueous molybdic acid solution having a pH of 6-8, U.S. Pat. No. 4,388,226 discloses a method of adding an aqueous solution of a bismuth salt to a suspension of a molybdenum compound, U.S. Pat. Nos. 4,212,766, 4,148,757 and 4,040,978 disclose methods of previously forming various molybdates, JP-B-52-22359 and U.S. Pat. No. 3,872,148 disclose methods of previously forming various bismuth compounds, U.S. Pat. No. 4,803,190 discloses a method of using bismuth oxide or bismuth oxycarbonate as a bismuth source, JP-A-2-59046 discloses a method of adjusting pH of a slurry containing at least one element selected from the group consisting of iron, bismuth and tellurium and a molybdenum compound to higher than 7, U.S. Pat. No. 5,059,573 discloses a method of adding a chelating agent to a molybdenum compound-containing slurry containing silica to adjust pH to 6 or higher, and U.S. Pat. No. 5,071,814 discloses a method of adjusting a slurry containing molybdenum to a pH of 6 or higher and then mixing a bismuth compound therewith.
As mentioned above, various methods have been proposed for attaining improvement of catalyst performance, such as devising the method of mixing aqueous molybdenum solution with bismuth compound or special selection of starting materials for bismuth. However, when these methods are applied to production of molybdenum-bismuth-containing composite oxide catalysts containing at least one metallic element selected from the group consisting of divalent metallic elements and trivalent metallic elements, yield of the desired oxidation products is not necessarily satisfactory.
BEST MODE FOR CARRYING OUT THE INVENTION
Molybdenum, bismuth, iron, nickel, chromium, potassium and the metallic element represented by F are essential components, and unless they are within the above compositional ranges, the object of the present invention cannot be attained.
When the catalyst composition of the present invention contains iron antimonate, it naturally contains antimony, and in this case, there are advantages that, for example, especially, selectivity of the desired product is improved and physical properties of the catalyst are also improved.
Moreover, when the catalyst of the present invention

Affiliated with

Also associated with

Rating

Catalyst for producing unsaturated nitrile 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 producing unsaturated nitrile, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Catalyst for producing unsaturated nitrile will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2990707