Organic compounds -- part of the class 532-570 series – Organic compounds – Amino nitrogen containing
Reexamination Certificate
1999-10-29
2001-08-28
Richter, Johann (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Amino nitrogen containing
C564S479000, C564S480000, C564S485000
Reexamination Certificate
active
06281387
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the synthesis of aliphatic, cyclic and aromatic alkanolamines and alkyleneamines (collectively referred to throughout the specification including the claims as “alkanolamines and alkyleneamines”) from alkanes and/or alkenes. More particularly, the present invention provides a process for synthesizing alkanolamines and alkyleneamines by selective partial oxidative amination of alkanes and/or alkenes. The invention further provides a regenerable catalyst which provides a favorable free energy for the selective partial oxidative amination reaction.
BACKGROUND OF THE INVENTION
Alkanolamines and alkyleneamines are currently manufactured using alkylene oxides and ammonia as the key starting raw materials. For example, monoethanolamine, di- and tri-ethanolamine and ethylenediamine are currently manufactured using ethylene oxide and ammonia as the starting raw materials. The manufacture of monoethanolamine requires high ammonia to ethylene oxide ratios in order to increase the selectivity to monoethanolamine. It is then necessary to refine and recycle the excess ammonia which significantly increases the cost of monoethanolamine production. Once monoethanolamine is formed, it is treated with ammonia by a reductive amination process to produce ethylenediamine and other higher acyclic and cyclic polyethyleneamines. Again, high ammonia ratios are employed to improve the selectivity to the desired end product, typically, ethylenediamine.
Ethylene oxide is a relatively expensive compound, and the high cost of this material also unfavorably impacts the economics of monoethanolamine and ethylenediamine manufacture. In the case of monoethanolamine, for example, the raw materials may account for at least 70% of the total monoethanolamine cost.
Another commercial process utilizes ethylene dichloride and ammonia for the synthesis of ethylenediamine and other higher homologs. This process is energy intensive and requires expensive refining equipment. Furthermore, the resultant hydrochloride salts of ammonia and the polyethyleneamines must undergo neutralization with caustic (usually sodium hydroxide) to give the free amine product. Separation of the polyethyleneamines and the salt is difficult, and the byproduct salt must be disposed of which further increases the cost of the process.
A process which could produce alkanolamines and alkyleneamines from alkanes and/or alkenes as the starting hydrocarbon raw materials would provide a desirable advantage over the current prior art. In the case of monoethanolamine and ethylenediamine, for example, using ethane and/or ethylene as the starting raw material(s) would provide significantly improved variable costs compared to ethylene oxide and ethylene dichloride. It would also avoid the need to handle ethylene oxide—a highly reactive chemical.
The partial oxidative amination of alkanes and alkenes provides a thermodynamically favorable route to alkanolamines and alkyleneamines, as demonstrated further below. The primary concern with respect to the partial oxidative amination of alkanes and alkenes is selectivity, i.e., the formation of desirable alkanolamines and alkyleneamines rather than the complete conversion of the starting materials to CO
2
and water. In addition, preventing or limiting the oxidation of ammonia and other nitrogen sources to NO
x
, type species and limiting NO
x
/hydrocarbon reactions are other significant concerns.
A process that effectively addresses these concerns would achieve a novel and practicable means of producing alkanolamines and alkyleneamines. Such an approach would also provide clear economic advantages over the present method of synthesizing these materials from ethylene oxide or ethylene dichloride.
SUMMARY OF THE INVENTION
The present invention meets these objectives by providing, in one aspect, a process for producing alkanolamines and/or alkyleneamines by reacting at least one of an alkane and an alkene with a source of oxygen and a source of nitrogen and, optionally, additional hydrogen to convert the alkane and/or alkene by partial oxidative amination to at least one of the desired end products.
Any source of nitrogen suitable for carrying out the reaction may be utilized, such as ammonia, hydrazine, amines, nitrous oxide in the presence of a reducing gas such as H
2
, hydrocarbon, etc., and other nitrogen-containing compounds. In the case of monoalkanolamines and alkyleneamines, ammonia is preferred.
The necessary oxygen may be obtained from any suitable source, including without limitation, oxygen, ozone, oxides of nitrogen, water, and alcohols. Preferably, oxygen is used to carry out the reaction. The O
2
may be fed at any concentration by mixing with N
2
, He, or other inert gases. A convenient and safe source of oxygen is air. The required oxygen may also be provided by a suitable metal oxide catalyst or by the reaction of a metal oxide catalyst with N
2
O, NO
x
or sulfur oxides which may be generated in situ or supplied to the reaction system indirectly. In a preferred embodiment of the invention, the oxygen is supplied by one or more reducible metal oxide catalysts that are regenerated by exposure to air, O
2
, other oxygen containing gases, or other suitable oxygen sources.
Sufficient hydrogen for the reaction is typically provided by the ammonia or amine utilized as the nitrogen source, by the alkane and/or alkene raw materials, or by hydroxyl groups present on the surface of the catalyst. However, in the event these sources do not contain sufficient hydrogen, an additional source of hydrogen may be directly or indirectly provided, for example, H
2
gas. The necessary hydrogen may also be provided by one or more hydrogenation/dehydrogenation metal catalysts.
In a second aspect, the invention relates to a metal or metal oxide catalyst which provides a favorable standard free energy for the partial oxidative amination reaction.
Reducible metal oxide catalysts have been found to be particularly suitable for synthesizing alkanolamines and alkaneneamines by partial oxidative amination. These types of metal oxides (referred to herein as “red-ox” catalysts) allow for the ready accessibility of lattice oxygen to promote the oxidation of the feed materials, which results in a corresponding reduction of the metal oxide. This is followed by re-oxidation of the catalyst by another oxygen source, such as O
2
or an oxygen-containing gas. Examples of effective red-ox catalysts include, but are not limited to, the oxides of cerium, iron, copper, nickel, lead, cadmium, molybdenum, vanadium, bismuth, manganese, barium, cobalt, strontium, tungsten, samarium, osmium, rhenium, rare earth elements, and mixtures of these oxides.
Those metals which are generally known as hydrogenation/dehydrogenation metals are also effective for carrying out the reaction, either alone or in combination with above-mentioned metal oxide catalysts. As explained in more detail below, it is believed that these catalysts generate highly reactive hydroperoxo and/or peroxo species from O
2
and H
2
and provide the oxygen and hydrogen necessary for the oxidative amination reaction. These catalysts include but are not limited to nickel, palladium, platinum, cobalt, rhodium, iridium, iron, ruthenium, copper, zinc, gold, silver and mixtures of these metals.
Typically, both the red-ox and hydrogenation/dehydrogenation catalysts are supported on suitable carriers such as cerias, titanias, zirconias, silicas, aluminas, ∝-alumina, silicon carbide, aluminum phosphate molecular sieves (AlPO's), high silica molecular sieve zeolites, MCM-type large pore zeolites, mixtures of these carriers, and other catalyst support materials well-known in the art.
REFERENCES:
patent: 4307250 (1981-12-01), Peterson et al.
Sharpless, K.B. et al., “Osmium-Catalyzed Vicinal Oxyamination of Olefins by Chloramine-T”,J. Org. Chem., vol. 41, No. 1, 1976, pp. 177-179.
Contractor, R.M., et al., “Butane Oxidation to Maleic Anhydride in a Recirculating Solids Reactor”,Catalysis1987, pp. 645-653.
Sharpless, K. B. et al
Bhasin Madan Mohan
King Stephen Wayne
Davis Brian J.
Richter Johann
Union Carbide Chemicals & Plastics Technology Corporation
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