Process for the synthesis of an aliphatic cyclic amine

Details Process for the synthesis of an aliphatic cyclic amine Process for the synthesis of an aliphatic cyclic amine

2001-03-27

2003-03-04

Shah, Mukund J. (Department: 1624)

Organic compounds -- part of the class 532-570 series

Organic compounds

Unsubstituted hydrocarbyl chain between the ring and the -c-...

C546S184000, C546S254000, C548S564000, C548S519000

Reexamination Certificate

active

06528647

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a process for the synthesis of an aliphatic cyclic amine. More particularly, the present invention relates to amino cyclization of terminal diols. In particular this invention relates to a process for the selective synthesis of cyclic imines by the amino cyclization of a hydrocarbons having from four to six carbons and which are characterized by two hydroxy groups in the terminal positions to yield a cyclic imine.
BACKGROUND OF THE INVENTION
3-Methylpiperidine is used as a vulcanization accelerator and as an additive to lubricant oil and 3-Methylpyridine is used both as a solvent and as an intermediate in the preparation of nicotinic acid. Cyclic amines are important compounds in the synthesis of drugs and for making of various reagents. Hexamethyleneimine is an important compound which is useful as an intermediate material for pharmaceuticals and agricultural chemicals, and also finds a wide range of applications as rubber vulcanization accelerators and other rubber chemicals, they are ingredients for textile lubricants, antistatic agents and finishing agents, corrosion inhibitors for metals, and modifiers or crosslinking agents for resins.
PCT application WO 90/00546 discloses the preparation of mixtures of 3-methylpiperidine and 3-methylpyridine starting from 2-methyl-1,5-diamino pentane by passing the gaseous starting material over a catalyst comprising metal oxides at 500° C.-600° C. Preferred catalysts are copper chromite, molybdenumoxide and vanadium oxide. These catalysts are preferably applied to a support. Depending on the reaction temperature, the ratio between piperidine and pyridine can be shifted to one or the other side. This patent specification also mentions the possibility of using acidic oxides, such as SiO
2
or silicon aluminium oxides, without further additives as catalysts. However, the yields achieved in this way are only moderate. No information is given on the catalyst activity over extended operating times.
U.S. Pat. No. 3,903,079 discloses a process for the cycloammonolysis of disubstituted alkanes containing primary amino and/or hydroxyl groups. The catalyst used is a metal aluminosilicate molecular sieve. Preferred metals are copper, palladium, manganese, nickel and chromium. The reaction was carried out in the presence of ammonia. The yields obtained were moderate. A yield of 75% was achieved in the preparation of piperidine from 1,5-pentanediol.
However, hexamethyleneimine has been obtained in small quantities from by-products which occur in the production of hexamethylenediamine by catalytic hydrogenation of adiponitrile or in the production of hexamethylenediamine by catalytic ammonolysis of 1,6-hexanediol. It has also been reported in Journal of the Chemical Society of Japan, Vol. 82, page 1701 (1961) that hexamethyleneimine was obtained in a yield of about 10% by heating hexamethylenediamine together with Raney nickel at 160° C. to 170° C., but a greater part of the product consisted of a resinous product or tar.
Chemische Berichte, Vol 96, page 924 (1963) also discloses that by heating hexamethylene diamine together with Raney nickel at 142° C.-143° C. in a solvent such as benzene, xylene or mesitylene, hexamethyleneimine is obtained in a yield of 24 to 38% (as the picrate salt), but at the same time, 1,6-bis-hexamethyleneiminohexane is formed in a yield of 12 to 47% (as the picrate salt). Furthermore, Canadian Pat. No. 920,606 (1973) discloses that hexamethyleneimine is obtained in a selectivity of 47 to 87% by contacting hexa methylenediamine with a hydrogenation catalyst at 150° C. to 250° C. in the presence of hydrogen. However, since the conversion of hexamethylenediamine is as low as 17 to 44%, a large quantity of unreacted hexamethylenediamine must be recovered by distillation. It is also necessary to reduce the amounts of by-products by adding hydrogen and ammonia during the reaction.
In an article titled “Equilibrium Conditions for Amination of Alcohols and Carbonyl Compounds”, Ind. Eng. Chem. Prod. Res. Develop., 11, 3, 333-337 (1972), Josef Pasek et al. described the influence of pressure, temperature, and initial composition on the equilibrium content of primary, secondary, and tertiary amines and unsaturated compounds.
In Catalysis of Organic Reactions, Blackburn, D. W., ed., 1990, at Chapter 14, M. Ford et al. review the selective synthesis of mixed alkyl amines by amine-alcohol reactions over hydrogen phosphate.
The amination of alcohols, aldehydes, and ketones using catalysts containing nickel, copper, or both, has been also been described, for example, in U.S. Pat. Nos. 3,520,933; 4,153,581; 4,152,353; and 4,409,399. These patents relates to selective production of diamines. U.S. Pat. No. 3,270,059 discloses the production of diaminoalkanes by passing an alkanediol, alkanolamine, alkylene oxide, or alkyleneimine along with either ammonia or an alkylamine in the presence of hydrogen and at an elevated temperature over a catalyst which contains sintered cobalt or nickel. The sintering process requires extra steps and high temperatures.
U.S. Pat. No. 4,290,946 discloses the synthesis of hexamethyleneimine from the deamino cyclisation of hexamethelene diamine over the raney nickel catayst in liquid phase but it suffers from the use of ammonia and hydrogen to reduce the catalysts prior to use it.
The amination of terminal diols to corresponding diamines is a known art over the metal oxides or on supported catalysts. But they suffer to yield cyclic imines by deamination and to avoid this they require to be carried out in presence of hydrogen gas. From the foregoing references it appears there that is a need in the art for an improved method of selectively producing cyclic imines by the amination of diols instead of diamines It would be very desirable in the art if a process were available for aminating a diol which is available in large volumes. This would provide an attractive route to an added-value commodity chemical.
OBJECTS OF THE INVENTION
The main object of the present invention is to provide a process for the preparation cyclic amines from diols which can be carried out on a commercial scale and achieves high yields. The catalyst activity should be maintained over long times.
SUMMARY OF THE INVENTION
The present invention relates to a process whrein high conversion of pentane diol, hexane diol and a high yield of piperidine and hexamethylenediamine respectively is maintained in the amination reaction of diol by inhibiting the formation of diamines and amino alcohols as by-products. These diamines find large volume applications in polyamide resins as monomer/comonomers, as well as price-competitive usage in lube oils, epoties, hot melt adhesives, and surfactants. They are also be useful in fuel additives, chelating agents, fungicides, and plastic lubricants.
Accordingly, the present invention relates to a process for the synthesis of an aliphatic cyclic imine having four to six carbons, said process comprising introducing into a reactor one or more C
4
to C
6
dihydric alcohols wherein the hydroxyl groups are in terminal positions reacting said C
4
to C
6
dihydric alcohol in a solvent and in the presence of excess ammonia in the presence of a metal containing ZSM-5 catalyst at a temperature in the range of 250° C. to 400° C. and weight hourly space velocity in the range of 0.25 to 1.00 h
−1
.
In one embodiment of the invention, the dihydric alcohol used is 1,4-Butane diol to obtain pyrrolidine or pyrrole.
In one embodiment of the invention, the dihydric alcohol used is 1,5-Pentane diol to obtain piperidine or pyridine.
In one embodiment of the invention, the dihydric alcohol used is 1,6-hexane diol to obtain hexamethylene imine.
In one embodiment of the invention, the solvent is selected from the group consisting of alcohols, ethers and water.
In one embodiment of the invention, the diol is introduced into the reactor in aqueous solution.
In one embodiment of the invention, the molar ratio of ammonia to hydroxyl groups is 5 to 100.
In one embodiment of the i

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