Organic compounds -- part of the class 532-570 series – Organic compounds – Amino nitrogen containing
Reexamination Certificate
1997-07-21
2002-02-26
Barts, Samuel (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Amino nitrogen containing
Reexamination Certificate
active
06350914
ABSTRACT:
The present invention relates to a process for preparing amines by reacting ammonia or primary or secondary amines with olefins at elevated temperatures and pressures in the presence of zeolites having an NES structure.
An overview of the methods for aminating olefins is given in “Functionalisation of Alkenes: Catalytic Amination of Monoolefins”, J. J. Brunet et al. J.Mol.Catal., 49 (1989), pages 235 to 259.
There are fundamentally two catalysis mechanisms. The olefin is coordinated to form a metal complex. This activated species can be attacked by the nucleophilic amine and form a higher aminated product. The amine can be chemisorbed on acid centers or metal centers (via metal amides) and be reacted in this activated form with the olefin.
Zeolites are very useful catalysts. They have a high number of catalytically active centers combined with a large surface area. The zeolites described differ in type and in the after-treatment (eg. thermal treatment, dealumination, acid treatment, metal ion exchange, etc.). Examples may be, found in U.S. Pat. Nos. 4,375,002, 4,536,602, EP-A-305 564, EP-A-101 921, DE-A-42 06 992.
EP-A-133 938, EP-A-431 451 and EP-A-132 736 disclose processes in which borosilicate, gallium silicate, aluminosilicate and iron silicate zeolites are used for the preparation of amines from olefins and refer to the possibility of doping these zeolites with alkali, alkaline earth and transition metals.
CA-A-2 092 964 discloses a process for preparing amines from olefins in which BETA-zeolites, which are defined as crystalline aluminosilicates having a particular composition and a pore size of more than 5 Å, are used. Preference is given to using metal- or halogen-modified Beta-zeolites.
All processes for synthesizing amines from olefins over these catalysts give a low amine yield or a low space-time yield, or lead to rapid deactivation of the catalysts.
It is an object of the present invention to remedy these disadvantages.
We have found that this object is achieved by a new and improved process for preparing amines of the general formula I
where
R
1
,R
2
,R
3
,R
4
,R
5
,R
6
are hydrogen, C
1
-C
20
-alkyl, C
2
-C
20
-alkenyl, C
2
-C
20
-alkynyl, C
3
-C
20
-cycloalkyl, C
4
-C
20
-alkyl-cycloalkyl, C
4
-C
20
-cycloalkyl-alkyl, aryl, C
7
-C
20
-alkylaryl or C
7
-C
20
-aralkyl,
R
1
and R
2
are together a saturated or unsaturated divalent C
3
-C
9
-alkylene chain and
R
3
or R
5
are C
21
-C
200
-alkyl, C
21
-C
200
-alkenyl or together a divalent C
2
-C
12
-alkylene chain,
by reacting olefins of the general formula II
where R
3
, R
4
, R
5
and R
6
are as defined above, with ammonia or primary or secondary amines of the general formula III
where R
1
and R
2
are as defined above, at from 200 to 350° C. and pressures of from 100 to 300 bar in the presence of a heterogeneous catalyst, wherein the heterogeneous catalyst used is a zeolite having an NES structure.
The process of the present invention can be carried out as follows:
The olefin II and ammonia or the primary or secondary amine III can be reacted at from 200 to 350° C., preferably from 220 to 330° C., particularly preferably from 230 to 320° C., and pressures of from 100 to 300 bar, preferably from 120 to 300 bar, particularly preferably from 140 to 290 bar, in the presence of zeolites having an NES structure as catalyst, eg. in a pressure reactor, and, preferably, the amine obtained is separated off and the unreacted starting materials are recirculated.
The present invention gives a very good yield at high selectivity and at a high space-time yield. In addition, the deactivation of the catalyst has been suppressed.
In the process of the present invention, even with a low excess of ammonia or amine, a high selectivity to the desired reaction product is achieved and the dimerization and/or oligomerization of the olefin used is avoided.
One embodiment of this process comprises feeding a mixture of ammonia and/or amines III with the olefin II in a molar ratio of 1:1 to 5:1 to a fixed-bed reactor and reacting this mixture at from 200 to 350° C. and a pressure of from 100 to 300 bar in the gas phase or in the supercritical state.
The desired product can be obtained from the mixture leaving the reactor by means of known methods, for example distillation or extraction, and can, if necessary, be brought to the desired purity by means of further separation operations. In general, the unreacted starting materials are preferably recirculated to the reactor.
It is possible to use monounsaturated or polyunsaturated olefins II, in particular those having from 2 to 10 carbon atoms or mixtures thereof, and polyolefins as starting materials. Owing to their less pronounced polymerization tendency, monoolefins are more suitable than diolefins and polyolefins, although the latter can be reacted equally selectively by means of higher excesses of ammonia or amine. The position of the equilibrium and thus the conversion to the desired amine is very strongly dependent on the reaction pressure selected. High pressure favors the addition product, although the pressure range up to 300 bar generally represents the optimum for technical and economic reasons. The selectivity of the reaction is influenced to a great extent by the temperature, as well as by parameters such as ammonia/amine excess and catalyst. Although the reaction rate of the addition reaction increases greatly with rising temperature, competing cracking and recombination reactions of the olefin are promoted at the same time. In addition, a temperature increase is not advantageous from a thermodynamic point of view. The position of the temperature optimum in respect of conversion and selectivity is dependent on the constitution of the olefin, the amine used and the catalyst and is usually in the range from 200 to 350° C.
Suitable catalysts for the amination of olefins are zeolites having an NES structure, preferably NU-87 zeolites, which are known, for example, from EP-A-377 291.
Zeolites having an NES structure have a two-dimensional pore system with the approximate dimensions 4.7×6.0 Å (Meier, Olson, Atlas of Zeolite Structure Types, 3rd Ed., 1992, Butterworth-Heinemann, pages 154 to 155). An example of a zeolite having an NES structure is NU-87 (Shannon et al., Nature 353 (1991), pp. 417 to 420). The structure of SSZ-37 (U.S. Pat. No. 5,254,514) has not yet been finally established, but it appears to be related to NU-87 (Nakagawa, Stud. Surf. Sci. Catal. 84 (1994), pages 323 to 330), so that for the purposes of this application it should also be included among the zeolites having an NES structure of the present invention.
Apart from the NES zeolites containing aluminum as trivalent element in the SiO
2
matrix, as is the case, for example, in NU-87, for the purposes of this application other elements are also possible if acid centers are created by their incorporation. This is the case, for example, for borozeolites, iron zeolites or gallium zeolites. The molar ratio of SiO
2
to the oxides of the trivalent elements are known as the modulus SiO
2
/M
2
O
3
(M=Al, B, Ga, Fe), can vary from virtually infinity to a few tens depending on the class of zeolite.
Apart from the classical zeolites based on SiO
2
, it is also possible to obtain analogous structures based on aluminum phosphates, known as AlPOs. If these contain aluminum and phosphorus in a ratio of greater than 1, they are likewise acid and can be used for the purposes of the present invention. If part of the phosphorus and/or both aluminum and phosphorus is replaced by silicon, this gives the SAPOs which are likewise acid. If various metal ions such as Li, B, Be, Mg, Ti, Mn, Fe, Co, Zn, Ga, Ge, As are present in addition to aluminum and phosphorus, the compounds are referred to as MeAPOs, or in the simultaneous presence of silicon as MeAPSOs, in which the negative charge of the Me
a
Al
b
P
c
Si
d
O
e
framework is in each case balanced by cations. All such molecular sieves having an NES structure are included among the catalysts of the present invention.
The zeolites having an NES stru
Dernbach Matthias
Eller Karsten
Kummer Rudolf
Barts Samuel
BASF - Aktiengesellschaft
Keil & Weinkauf
LandOfFree
Preparation of amines from olefins over zeolites having an... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Preparation of amines from olefins over zeolites having an..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Preparation of amines from olefins over zeolites having an... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2947706