Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
2000-06-23
2001-08-28
Seaman, D. Margaret (Department: 1625)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
active
06281362
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing pyridine bases by reacting in a gas-phase an aliphatic aldehyde, aliphatic ketone or mixture thereof with ammonia in the presence of a catalyst.
A method for producing pyridine bases by reacting in a gas-phase an aliphatic aldehyde, aliphatic ketone or mixture thereof with ammonia in the presence of a catalyst is known. Various methods are reported, for example, a method in which an amorphous silica-alumina is used as a catalysts, a method in which zeolites such as aluminosilicate and the like are used, as well as other methods. Among the catalysts, zeolite is suitable as a catalyst for producing pyridine bases in which a gas-phase reaction is conducted under high temperature condition, due to its excellent heat-resistance.
As the zeolite used as a catalyst for producing pyridine bases, for example, heteosilicate such as ferrosilicate, borosilicate and gallosilicate, in addition to aluminosilicate, are known. These zeolites are used singly as a catalyst. Alternatively, they are allowed to contain an ion and/or compound of various elements, such as copper, zinc, cadmium, bismuth, chromium, molybdenum, tungsten, cobalt, nickel, ruthenium, rhodium, palladium, iridium and the like, to give a catalyst to be used.
In the production of pyridine bases, it is known that main products, the pyridine bases, are determined by combination of the raw materials, an aliphatic aldehyde and an aliphatic ketone. Typical examples of them are shown in Table 1.
TABLE 1
Raw materials
(Aliphatic aldehyde,
Main Product
Aliphatic ketone)
(Pyridine bases)
Acetaldehyde
&agr;-picoline + &ggr;-picoline
Acetaldehyde + formaldehyde
Pyridine + &bgr;-picoline
Acrolein
&bgr;-picoline
Acrolein + acetaldehyde
Pyridine
Acrolein + propionaldehyde
&bgr;-picoline
Propionaldehyde + formaldehyde
3,5-lutidine
Crotonaldehyde + propionaldehyde
3,4-lutidine
Crotonaldehyde + acetone
2,4-lutidine
Formaldehyde + acetone
2,6-lutidine
Acetone
2,4,6-collidine
Methacrolein + methyl ethyl ketone
3,5-lutidine + 2,3,5-collidine
As described above, various pyridine bases can be produced by reacting in a gas-phase an aliphatic aldehyde, aliphatic ketone or mixture thereof with ammonia in the presence of a zeolite as a catalyst. However, the yields of pyridine bases produced by conventional methods are yet low.
For example, in the comparative examples described below, which were conducted by the present inventors and in which acetaldehyde is reacted with ammonia to produce &agr;-picoline and &ggr;-picoline according to the above-described conventional methods, namely, by using aluminosilicate, ferrosilicate or the like as the catalyst, the yields of &agr;-picoline and &ggr;-picoline were, respectively, 17.6% and 18.5% when aluminosilicate was used, 18.6% and 17.5% when ferrosilicate was used, and 17.3% and 19.3% when gallosilicate was used.
Thus, the yields of the intended pyridine bases in conventional methods are not yet satisfactory, and further improvement in the yield is desired.
The present inventors have intensively studied for finding a method that can produce pyridine bases in higher yield. As a result, the present inventors have found that, when pyridine bases are produced by reacting in a gas-phase an aliphatic aldehyde, aliphatic ketone or mixture thereof with ammonia in the presence of a zeolite containing titanium and/or cobalt and silicon as zeolite constituent elements in which the atomic ratio of silicon to titanium and/or cobalt is about 5 to about 1000, pyridine bases can be produced at higher yield as compared with the conventional case in which a zeolite such as aluminosilicate, ferrosilicate or the like is used as the catalyst. Thus, the present invention has been completed.
SUMMARY OF THE INVENTION
The present invention provides a method for producing pyridine bases which comprises reacting in a gas-phase an aliphatic aldehyde, aliphatic ketone or mixture thereof with ammonia in the presence of a zeolite containing titanium and/or cobalt and silicon as zeolite constituent elements in which the atomic ratio of sillcon to titanium and/or cobalt is about 5 to about 1000.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The production of pyridine bases according to the present invention is conducted by using an aliphatic aldehyde, aliphatic ketone or mixture thereof corresponding to the intended pyridine bases and allowing then to react in a gas-phase with ammonia in the presence of the specific zeolite described above.
The aliphatic aldehyde is preferably an aliphatic aldehyde having 1 to 5 carbon atoms. Examples thereof include saturated aliphatic aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, butylaldehyde and the like, and unsaturated aliphaitic aldehydes such as acrolein, methacrolein, crotonaldehyde and the like. The aliphatic ketone is preferably an aliphatic ketone having 3 to 5 carbon atoms. Examples thereof include acetone, methyl ethyl ketone, diethyl ketone and the like. Dimers, trimers, other oligomers and polymers which generate an aliphatic aldehyde or aliphatic ketone can also be used as the raw material. Relation between the raw material, namely combinations of aliphatic aldehydes and aliphatic ketones, and the main product, namely the pyridine bases, are exemplified in the above-described Table 1.
As described above, a zeolite containing titanium and/or cobalt and silicon as zeolite constituent elements in which the atomic ratio of silicon to titanium and/or cobalt is about 5 to about 1000 and the constraint index is about 0.8 to about 12 is used as the catalyst in the reaction of the present invention. Hereinafter, the above-described zeolite which is used as the catalyst in the present invention is referred to as titan and/or cobaltsilicate zeolite. Examples of the titan and/or cobaltsilicate zeolite include titanosilicates containing titanium and siliccon as zeolite constituent elements, cobaltsilicates containing cobalt and silicon as zeolite constituent elements, and zeolites containing titanium, cobalt and silicon as zeolite constituent elements. One or more of them can be used as the catalyst in the reaction of the present invention. The atomic ratio of silicon to titanium and/or cobalt in the titan and/or cobaltsilicate zeolite used in the present invention is preferably from about 10 to about 500.
The catalyst used in the present invention can be prepared by a conventionally known method. Various titan and/or cobaltsilicate zeolites, which are different from each other in the atomic ratio of silicon to titanium and/or cobalt, crystal structure or the like, can be obtained easily. For example, they can be prepared in the same manner as described in Japanese Patent Application Laid-Open (JP-A) Nos. 63-54358, 60-12135, 56-96720 and 55-7598, Journal of Catalysis, 130, 440 (1991), Applied Catalysis A: General, 126, 51 (1995), Zeolite, 17(4), 354 (1996) and the like.
The crystal structure of the catalyst used in the present invention is not particularly limited, although those having a pentasil type crystal structure are preferable. Among others, those having a MFI type or MEL type crystal structure are more preferable.
In the present invention, a titan and/or cobaltsilicate zeolite can be used as it is, although a titan and/or cobaltsilicate zeolite being allowed to further contain an ion and/or compound of one or more elements selected from group I to XVII elements is preferable, since when it is used, the yield of pyridine bases increases.
The group I to XVII elements are elements listed in the 18-groups type periodic table of element. Specific examples thereof include Li, K, Rb and Cs as group I elements, Mg, Ca, Sr and Ba as group II elements, Sc, Y and lanthanoid elements, La, Ce, Pr, Nd, Er and Yb, as group III elements, Ti, Zr and Hf as group IV elements, V, Nb and Ta as group V elements, Cr, Mo and W as group VI elements, Mn, Tc and Re as group VII elements, Fe, Ru and Os as group VIII elements, Co, Rb and Ir an group IX elements, Ni, Pd and P
Iwamoto Keisuke
Nakaishi Yoko
Shoji Takayuki
Koel Chemical Company, Ltd.
Seaman D. Margaret
Stevens Davis Miller & Mosher L.L.P.
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