Chemistry of hydrocarbon compounds – Unsaturated compound synthesis – By dehydrogenation
Reexamination Certificate
2002-12-02
2004-03-02
McKane, Joseph K. (Department: 1626)
Chemistry of hydrocarbon compounds
Unsaturated compound synthesis
By dehydrogenation
Reexamination Certificate
active
06700029
ABSTRACT:
The present invention relates to the oxidative dehydrogenation of alkanes for the production of olefins and, more particularly, to the use of catalyst systems comprising oxidative dehydrogenation catalysts and mixed metal oxide catalysts for the preparation of unsaturated carboxylic acids and unsaturated nitriles from alkanes.
The production of alkenes (e.g., C
2
-C
4
alkenes) is most commonly accomplished by the thermal cracking of hydrocarbons. This is a process requiring large amounts of energy and tends to result in the generation of undesirable by-products (such as coke), which often have the potential to reduce reactor efficiency and require occasional shutdowns.
In recent years, it has been proposed to perform an oxidative dehydrogenation reaction with a paraffinic hydrocarbon to yield the desired alkene. Efforts in the field have been reported by a number of different groups. See, e.g., thesis entitled “Catalysts for the Oxidative Dehydrogenation of Alkanes at Millisecond Contact Times” by Dr. Derrick W. Flick (2000) and his preprint of a paper Flick, et al. “Olefins by Oxidative Dehydrogenation of Propoane and Butanes over a Promoted Chromia Catalyst Supported on a Foam Monolith”. In the latter, Cu is used as a promoter. It is noted that Flick's selection of catalyst composition necessitates relatively high autothermal run temperatures, e.g., as high as 400° C. higher than desired for certain reactions. Because of the higher temperatures and relatively low efficiency catalysts, conversion of alkane is low, olefin selectivity is low, CO and CO
2
selectivity is high and catalyst deactivation is more rapid.
Published International Patent Application WO 00/14180 (Mar. 16, 2000), entitled “Autothermal Process for the Production of Olefins”, recognizes that “[I]t would be desirable to discover a catalytic process wherein a paraffinic hydrocarbon is converted to an olefin in a conversion and selectivity comparable to, or better than, commercial thermal cracking processes. It would be desirable if the catalytic process were to produce small quantities of deep oxidation products, such as carbon monoxide and carbon dioxide. It would also be desirable if the process were to achieve low levels of catalyst coking. It would be even more desirable if the process could be easily engineered without the necessity for a large, capital intensive, and complex cracking furnace. Finally, it would be most desirable if the catalyst was stable and the catalytic support not prone to fracture.” The published application does not disclose the use of reducible metal oxides promoted with Group 8 metals. Moreover, the autothermal temperatures utilized were typically high, i.e. between 800° C. and 1100° C.
S. Golunski, et al., Chem. Commun., 2000, pp 1593-1594, “Lowering the Operating Temperature of Selective Oxidation Catalysts” indicated that “. . . by incorporating palladium into oxidative dehydrogenation catalysts, a key step in the usual Mars-van Krevelen redox cycle is by-passed, which results in a decrease in operating temperature of around 200° C., as compared to the unmodified iron(III) oxide.” The authors incorporated palladium into Fe
2
O
3
and Bi
2
MoO
6
. They did not use three-dimensional catalytic forms; their contact times were long, i.e. 0.6 seconds (600 milliseconds); they did not run autothermally, i.e. they applied heat to the catalyst bed; and they prepared butadiene from butene. See also, Golunski, et al, U.S. Pat. No. 5,877,377 (Mar. 2, 1999).
Unsaturated carboxylic acids such as acrylic acid and methacrylic acid are industrially important as starting materials for various synthetic resins, coating materials and plasticizers. Commercially, the current process for acrylic acid manufacture involves a two-step catalytic oxidation reaction starting with a propene feed. In the first stage, propene is converted to acrolein over a modified bismuth molybdate catalyst. In the second stage, acrolein product from the first stage is converted to acrylic acid using a catalyst composed of mainly molybdenum and vanadium oxides. In most cases, the catalyst formulations are proprietary to the catalyst supplier, but, the technology is well established. Moreover, there is an incentive to develop a single step process to prepare the unsaturated acid from its corresponding alkene. Therefore, the prior art describes cases where complex metal oxide catalysts are utilized for the preparation of unsaturated acid from a corresponding alkene in a single step.
European Published Patent Application No. 0 630 879 B1 discloses a process for producing an unsaturated aldehyde and a carboxylic acid which comprises subjecting propene, isobutene or tertiary butanol to gas phase catalytic oxidation with molecular oxygen in the presence of (i) a catalyst composite oxide represented by the formula
Mo
a
Bi
b
Fe
c
A
d
B
e
C
f
D
g
O
x
wherein A represents
−
Ni and/or Co, B represents at least one element selected from Mn, Zn, Ca, Mg, Sn and Pb, C represents at least one element selected from P, B, As, Te, W, Sb and Si, and D represents at least one element selected from K, Rb, Cs and Tl; and wherein, when a=12, 0<b≦10, 0<c≦10, 1≦d≦10, 0≦e≦10, 0≦f≦20 and 0≦g≦2, and x has a value dependent on the oxidation state of the other elements; and (ii) a molybdenum oxide which in itself is substantially inert to said gas phase catalytic oxidation to provide the corresponding unsaturated aldehyde and unsaturated carboxylic acid.
Japanese Laid-Open Patent Application Publication No. 07-053448 discloses the manufacture of acrylic acid by the gas-phase catalytic oxidation of propene in the presence of mixed metal oxides containing Mo, V, Te, O and X wherein X is at least one of Nb, Ta, W, Ti, Al, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ni, Pd, Pt, Sb, Bi, B, In, Li, Na, K, Rb, Cs and Ce.
Published International Application No. WO 00/09260 discloses a catalyst for selective oxidation of propene to acrylic acid and acrolein containing a catalyst composition comprising the elements Mo, V, La, Pd, Nb and X in the following ratio:
Mo
a
V
b
La
c
Pd
d
Nb
e
X
f
wherein X is Cu or Cr or a mixture thereof,
a is 1,
b is 0.01 to 0.9,
c is >0 to 0.2
d is 0.0000001 to 0.2,
e is 0 to 0.2, and
f is 0 to 0.2; and
wherein the numerical values of a, b, c, d, e and f represent the relative gram-atom ratios of the elements Mo, V, La, Pd, Nb and X, respectively, in the catalyst and the elements are present in combination with oxygen.
Commercial incentives also exist for producing acrylic acid using a lower cost propane feed. Therefore, the prior art describes cases wherein a mixed metal oxide catalyst is used to convert propane to acrylic acid in one step.
U.S. Pat. No. 5,380,933 discloses a method for producing an unsaturated carboxylic acid comprising subjecting an alkane to a vapor phase catalytic oxidation reaction in the presence of a catalyst containing a mixed metal oxide comprising, as essential components, Mo, V, Te, O and X, wherein X is at least one element selected from the group consisting of niobium, tantalum, tungsten, titanium, aluminum, zirconium, chromium, manganese, iron, ruthenium, cobalt, rhodium, nickel, palladium, platinum, antimony, bismuth, boron, indium and cerium; and wherein the proportions of the respective essential components, based on the total amount of the essential components, exclusive of oxygen, satisfy the following relationships: 0.25<r(Mo)<0.98, 0.003<r(V)<0.5, 0.003<r(Te)<0.5 and 0.003<r(X)<0.5, wherein r(Mo), r(V), r(Te) and r(X) are the molar fractions of Mo, V, Te and X, respectively, based on the total amount of the essential components exclusive of oxygen.
Published International Application No. WO 00/29106 discloses a catalyst for selective oxidation of propane to oxygenated products including acrylic acid, acrolein and acetic acid, said catalyst system containing a catalyst composition comprising
Mo
a
V
b
Ga
c
Pd
d
Nb
e
X
f
wherein X is at least one element selected from La, Te, Ge, Zn, Si, In and W,
as 1,
b is 0.01 to 0.9,
c
Bogan, Jr. Leonard Edward
Gaffney Anne Mae
Han Scott
Heffner Michele Doreen
Song Ruozhi
McKane Joseph K.
Shiao Robert
LandOfFree
Processes for the preparation of olefins, unsaturated... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Processes for the preparation of olefins, unsaturated..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Processes for the preparation of olefins, unsaturated... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3199033