Triethylenediamine production using phosphate catalysts

Details Triethylenediamine production using phosphate catalysts Triethylenediamine production using phosphate catalysts

2000-03-23

2001-11-13

Berch, Mark L. (Department: 1624)

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

Organic compounds

Nitrogen attached directly or indirectly to the purine ring...

Reexamination Certificate

active

06316621

ABSTRACT:

BACKGROUND OF THE INVENTION
Organic synthesis by condensation reactions resulting in the loss of a molecule of water or of ammonia is well known in the art. Certain of such reactions are generally effected in the presence of acidic catalysts. An important area in which such acid catalysis has been employed is in cyclization reactions as in the synthesis of triethylenediamine and its C-substituted homologues. The catalysts are typically solid products of the Lewis acid type.
One group of catalysts which have been found to be effective for acid catalyzed organic condensation reactions such as those used to produce triethylenediamine (also referred to herein as TEDA) are phosphate catalysts. The following patents provide examples of such phosphate catalysts.
U.S. Pat. No. 3,297,701 (Brader et al., 1967) discloses the use of metal phosphate catalysts such as aluminum phosphate, calcium phosphate and cobalt phosphate, for synthesis of TEDA and C-substituted TEDA from piperazines or alkanolamines.
U.S. Pat. No. 4,405,784, U.S. Pat. No. 4,514,567, and U.S. Pat. No. 4,521,600 (Wells et al, 1983-1985) disclose the use of strontium monohydrogen phosphate (SrHPO
4
), strontium pyrophosphate (Sr
2
P
2
O
7
), strontium dihydrogen phosphate (Sr(H
2
PO
4
)
2
), the pyrophosphate, monohydrogen phosphate and dihydrogen phosphate of copper, magnesium, calcium, barium, zinc, aluminum, lanthanum, cobalt, nickel, cerium and neodymium, and mixtures thereof, as effective catalysts for organic condensation reactions especially the reaction to form TEDA. The catalysts are made by reacting a soluble salt of one of the metals with the mono- or diphosphate of an alkali metal or ammonium. The pH of the reaction mixture is adjusted to 5±3 in order to precipitate out the mono- or dihydrogen phosphate of the metal.
U.S. Pat. No. 4,757,143 (Vanderpool et al, 1988) discloses the conversion of cyclic and acyclic hydroxyethyl ethylenepolyamines to TEDA using a catalyst composed of zirconia or titania to which from 0.5 to about 7 wt % of phosphorous has been thermally chemically bonded in the form of phosphate linkages.
U.S. Pat. No. 5,037,838 (Zimmerman et al, 1991) discloses the conversion of N-hydroxyethyl piperazine to TEDA using a titania-supported tungstopyrophosphate catalyst.
BRIEF SUMMARY OF THE INVENTION
This invention is directed to a new method of making phosphate-based catalysts which are useful for the production of triethylenediamine (TEDA). The catalysts are prepared by mixing phosphoric acid with a substantially water insoluble alkaline earth metal salt such that the phosphorus to alkaline earth metal molar ratio is less than 1. An aqueous slurry of the salt, such as strontium carbonate, calcium carbonate, or barium carbonate, is mixed with an aqueous solution of phosphoric acid to form an alkaline earth hydrogen phosphate. Since less than stoichiometric amounts of alkaline earth metal salt and acid are used, some of the alkaline earth metal salt remains unreacted and is present in the precipitated product. The product, containing alkaline earth metal hydrogen phosphate and the starting alkaline earth metal salt, is filtered and dried. The mixture can be used as a catalyst in the production of TEDA from, for example, mono- and di-substituted piperazines, such as hydroxyethylpiperazine and aminoethylpiperazine, ethanolamines and substituted ethanolamines, and crude hydroxyethylpiperazine containing piperazine, hydroxyethylpiperazine, bis-hydroxyethylpiperazine, and water.
There are several advantages to this method of making the alkaline earth metal hydrogen phosphate compared to the known method of reacting an alkaline earth metal nitrate with sodium hydrogen phosphate, both of which are in solution:
the alkaline earth metal salt does not need to be put into solution before reacting it with phosphoric acid;
the catalyst does not need to be washed to remove unwanted metals such as sodium; and
the cost of the raw materials is much lower.
It has also been found that the product made by the method of this invention has much better activity and selectivity in making TEDA from hydroxyethylpiperazine than catalysts formed from a known method.
DETAILED DESCRIPTION OF THE INVENTION
Preparation of alkaline earth metal hydrogen phosphates can be carried out by first forming an aqueous slurry of an alkaline earth metal salt which is substantially insoluble in water, such as strontium carbonate, barium carbonate, or calcium carbonate. By “substantially insoluble in water” is meant that the solubility in water at ambient temperature (i.e., approximately 25° C.) is less than 1 part per 100 parts water.
An aqueous solution of phosphoric acid, for example, an 85% aqueous solution, is added to the alkaline earth metal salt slurry, with stirring, in an amount that the molar ratio of phosphoric acid to alkaline earth metal salt is less than 1; preferably less than 0.8. The reaction can be carried out at ambient temperature, i.e., approximately 25° C., and atmospheric pressure.
The product precipitate is a mixture of the alkaline earth metal hydrogen phosphate salt and unreacted alkaline earth metal salt. The molar ratio of phosphorous to alkaline earth metal in the product is less than 1; preferably, less than 0.8. The precipitate is filtered and can then be washed, for example with water, although washing is not required. The filtered precipitate can then be dried.
For use as a catalyst, the product may be employed in the form of irregular particles of a desired size range by breaking up the washed and dried filter cake or in the form of regular shaped pellets obtained by known methods of casting, pelletizing or extruding. The product may also be deposited or otherwise impregnated into the pores of a microporous substrate such as alumina, silica, silica-alumina, and the like.
In using the catalyst of the present invention to catalyze organic condensation reactions, substantially the same conditions may be employed as when using known catalysts. For optimum results, however, some adjustment in temperature, diluent, and/or space rate may be found beneficial.
A continuous process is typically used in the production of the triethylenediamine. The temperature range is about 285 to 420° C., preferably 300 to 390° C., the pressure range is about 0.1 to 1.5 atmospheres (101.4 to 152.03 kPa), preferably 0.3 to 1.0 atm (30.3 to 101.4 pKa), and the liquid hourly space velocity (LHSV) of organic feedstock per volume of catalyst is in the range of about 0.05 to 1.5, preferably 0.1 to 0.3.
The reaction an be carried out in the presence of an inert gas such as nitrogen, argon or helium.
In the preparation of TEDA, the organic feedstock includes mono- and di-substituted piperazines selected from the group consisting of hydroxyethylpiperazine, aminoethylpiperazine, ethanolamines, and substituted ethanolamines. The catalysts of this invention are relatively uneffected by the purity of the feedstock. For example, high conversion and good yields can be obtained from crude hydroxyethylpiperazine containing, in addition to the hydroxyethylpiperazine, piperazine, bis-hydroxyethylpiperazine, and water.


REFERENCES:
patent: 3297701 (1967-01-01), Brader et al.
patent: 4405784 (1983-09-01), Wells
patent: 4514567 (1985-04-01), Wells
patent: 4521600 (1985-06-01), Wells et al.
patent: 4695661 (1987-09-01), Homann et al.
patent: 4757143 (1988-07-01), Vanderpool et al.
patent: 5037838 (1991-08-01), Zimmerman et al.
patent: 5118651 (1992-06-01), Gubelmann et al.
patent: 5162531 (1992-11-01), King
patent: 5-17461 (1993-01-01), None

Affiliated with

Also associated with

Rating

Triethylenediamine production using phosphate catalysts does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Triethylenediamine production using phosphate catalysts, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Triethylenediamine production using phosphate catalysts will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2603549