Organic compounds -- part of the class 532-570 series – Organic compounds – Four or more ring nitrogens in the bicyclo ring system
Reexamination Certificate
2000-08-18
2002-09-03
Rotman, Alan L. (Department: 1625)
Organic compounds -- part of the class 532-570 series
Organic compounds
Four or more ring nitrogens in the bicyclo ring system
C544S336000, C546S314000
Reexamination Certificate
active
06444815
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a process for preparing a heteroaromatic aldehyde by catalytic reaction of an alkyl-substituted heteroaromatic compound with molecular oxygen in a gaseous phase. The heteroaromatic aldehyde is a useful compound for various applications such as an raw material for pharmaceutical and agricultural chemicals.
BACKGROUND ART
As a process for preparing a heteroaromatic aldehyde by catalytic reaction of an alkyl-substituted heteroaromatic compound with molecular oxygen, for example German Patent Application DD 298234 Specification discloses a process for preparing 4-pyridinecarbaldehyde by catalytic reaction of 4-methylpyridine with molecular oxygen in a gaseous phase with divanadyl pyrophosphate [(VO)
2
P
2
O
7
] as a catalyst.
The present inventors found that, as shown in Comparative Examples, selectivity of 4-pyridinecarbaldehyde was maximum of 60.9% in case of the catalytic reaction of 4-methylpyridine with molecular oxygen in the presence of divanadyl pyrophosphate as the catalyst in a gaseous phase. It was also found that, employing 3-methylpyridine instead of 4-methylpyridine, the selectivity of 3-aldehyde pyridine was also low in case of preparation of 3-pyridinecarbaldehyde by catalytic reaction of 3-methylpyridine with molecular oxygen in a gaseous phase.
Further, according to knowledge of the present inventors, in case of employing divanadyl pyrophosphate as a catalyst, yield of the desired compound (4-pyridinecarbaldehyde, 3-pyridinecarbaldehyde) became extremely low by decreasing an amount of molecular oxygen to increase a concentration of the substrate (4-methylpyridine, 3-methylpyridine) in the reaction materials in order to improve productivity.
Therefore, the processes described above is not satisfactory as the industrial process for preparing a heteroaromatic aldehyde such as pyridinecarbaldehyde, and a process which may prepare a heteroaromatic aldehyde in improved selectivity is desired.
The object of the present invention is to provide a process for solving the problems of the processes in the prior art, namely a process for preparing a heteroaromatic aldehyde by catalytic reaction of an alkyl-substituted heteroaromatic compound with molecular oxygen in a gaseous phase, wherein the heteroaromatic aldehyde is prepared in high selectivity.
DISCLOSURE OF INVENTION
The present inventors have found, as a result of effortful studying in order to solve the above described problems, that the heteroaromatic aldehyde may be prepared from an alkyl-substituted heteroaromatic compound in high selectivity, if the heteroaromatic aldehyde is prepared by catalytic reaction of the alkyl-substituted heteroaromatic compound with molecular oxygen in a gaseous phase, wherein the catalyst is an oxide containing vanadium, phosphorus, aluminium and silicon, and a part or all of the oxide is diluted with a solid inert to the reaction.
Namely, the present invention relates to a process for preparing a heteroaromatic aldehyde by catalytic reaction of an alkyl-substituted heteroaromatic compound with molecular oxygen in a gaseous phase in the presence of a catalyst, which comprises employing an oxide containing vanadium, phosphorus, aluminium and silicon as a catalyst, and diluting a part or all of the oxide present as a catalyst layer in a reactor with a solid inert to the reaction.
REFERENCES:
patent: 5059716 (1991-10-01), Joentgen et al.
patent: 298 234 (1987-02-01), None
patent: 11-35561 (1999-02-01), None
HCaplus DN 130:209602, English Abstract JP 11035561. Feb. 1999.*
International Search Report.
Nakaishi Toru
Nishiyama Tetsushi
Shoji Takayuki
Desai Rita
Koei Chemical Co. Ltd.
Rotman Alan L.
Sughrue & Mion, PLLC
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