DE1445418B2 - METHOD OF MANUFACTURING 1,4-DIAZABICYCLO ANGULAR CLAMP TO 2,2,2 ANGLE CLAMP TO OCTANE - Google Patents

Description

The invention relates to the production of 1,4-diazabicyclo [2.2.2] octane by passing over it of gaseous N-Hydroxyäthylpiperazin over solid, acidic, silica-containing cracking catalysts in increased space-time yields.

1,4-Diazabicyclo [2.2.2] octane is used as a catalyst for base-catalyzed reactions, particularly in used in the manufacture of polyurethane plastics, elastomers and foams. Although this Compound was already known from the literature, its first large-scale production only succeeded in more recently by processes that rely on the vapor phase reaction of certain alkylene polyamines use a solid, acidic catalyst; (See, for example, U.S. Patent 29 37 176). With the reinforced Demand for this compound has turned attention to improved manufacturing processes to achieve increased yields and / or lower production costs.

Previous attempts to make 1,4-diazabicyclo [2.2.2] octane ring closure of a / 5-substituted N-ethylpiperazine were unsuccessful or produced yields of no more than about 1 to a few percent. After several unsuccessful Hromatka described experiments in Ber. 75 B, 1302 [1942] the production of 1,4-diazabicyclo- [2,2,2] octane in medium-good yields by carefully controlled heating of N - /? - bromoethylpiperazine hydrobromide; lower yields were obtained from the corresponding hydrochloride, while the corresponding N-oxyethyl compound produced only very low yields.

The conversion of N-mono- and N, N'-bis-hydroxyäthylpiperazinen to 1,4-diazabicyclo [2.2.2] octane by catalytic vapor phase reaction Silica-alumina is from I s h i g u r ο and employees in Journ. Pharm. Soc. Japan, 75, 1370 [1955] (cf. Chem. Abs. 50, 10 106 [1956]). According to U.S. Patent 2985658 acceptable yields of 1,4-diazabicyclo- [2.2.2] octane obtained from N-aminoethylpiperazine over an acidic, silica-containing cracking catalyst.

The aim of the invention is now a process which improves the yields of 1,4-diazabicyclo [2.2.2] octane supplies.

The process of the present invention for the preparation of 1,4-diazabicyclo [2.2.2] octane by passing over of gaseous N-Hydroxyäthylpiperazin on fe ste, acidic, silicic acid-containing cracking catalysts ib now characterized in that the implementation at 260 to 427 ° C with a space velocity from about 0.2 to 1.0, based on the volume of the N-Hydroxyäthylpipen measured as a liquid. interest per unit volume of the catalyst per hour in the presence of nitrogen or benzene as an inert Performs diluent.

ίο The inert diluent is usually i: use an amount of at least 2 moles of diluent per mole of the starting material ten N-Hydroxyäthylpiperazins present.

In a preferred embodiment of the inven tion, the liquid starting material and de gaseous nitrogen separately introduced into a closed reaction vessel, which dei a fixed bed contains heated catalyst in granular or tablet form; the vaporous reaction products ao are continuously removed at the opposite end of the catalytic reaction vessel The benzene, which is liquid at room temperature, is used in this form in a mixture with the starting material or introduced separately. The reaction takes place at temperatures of 260 to 427 ° C., preferably before about 343 to 371 ° C, and at a space velocity of about 0.2 to 1.0 by volume of the N-hydroxyethylpiperazine measured as a liquid per unit volume of catalyst prc Hour. Although superatmospheric prints can be applied, they cater to one Working at atmospheric or sub-atmospheric pressure has no significant advantage. The diluent can be used in amounts of up to 10 or more moles / mole of N-Hydroxyäthylpiperazin, preferably ir Ratios between 3 to 5 moles / mole, use: will.

The catalyst used in the preparations of the following example was an activated koalin catalyst, which had been prepared according to the method of U.S. Patent No. 29 04 520.

Other siliceous cracking catalysts useful under practically similar conditions include acid activated bentonite clays and silica-alumina type gels, or those siliceous gels which contain zirconia or magnesia in place of all or part of the alumina. The silica-containing cracking catalysts generally have a surface area of at least 80 m ² / g, with silica-alumina catalysts having a surface area of at least 180 m ² / g being preferred. In general, for optimal results, the higher the catalyst activity, the lower the reaction temperature that can be used.

Due to the high concentrations of 1,4-diazabicyclo [2.2.2] octane achieved according to the invention The majority of the 1,4-diazabicyclo [2.2.2] octane may be the reaction effluent recovered as a solid of good purity after cooling. This solid is essentially a hydrate of 1,4-diazabicyclo [2.2.2] octane together with some mother liquor.

The process according to the invention is carried out in the gaseous state. In contrast, will the method of the German Auslegeschrift 11 32 137 carried out in the liquid state, and the respective Working conditions are therefore not

teres comparable. In the process according to the invention there are 'very good yields, and it is without further possible to do this continuously. Compared to the known method results there is also the advantage that the reaction can be carried out in a much shorter time, so that with appropriate recycling the space-time yields are higher than with the known Procedure. The new method is thus superior to the known method.

example

In batches 1 and 2, according to the invention, N-hydroxyethylpiperazine was used under the conditions shown in the table over an activated kaolin catalyst into a reaction vessel with a fixed bed directed. Approaches 3 and 4 are comparative examples in which no diluent is used.

The reported liquid hourly space velocity (LHSV) in the table above is for on all liquid feed. In batch 1, it includes benzene and N-hydroxyethylpiperazine. It can be seen that for all process conditions over the range used (residence time and temperature) the use of the diluent significantly improves the yield (almost doubling in some cases) on 1,4-diazabicyclo [2.2.2] octane.

The 1,4-diazabicyclo [2.2.2] octane was obtained as follows:

The liquid effluent obtained from the reaction vessel was fractionated and that at 165 bis 175 ° C boiling fraction collected. A sample thereof was subjected to gas chromatography. By integrating the area below the 1,4-diazabicyclo [2.2.2] octane tip, calculate the yield in each case.

On cooling, crystals of 1,4-diazabicyclo [2.2.2] octane separate in the form of the fraction of a hydrate. The fraction obtained can also be distilled again and then sublimated subject to obtaining the desired compound. The by mass spectroscopy or analysis The values obtained agree well with the required values; 159 ° C.

Table

approach

LHSV (space velocity)

Temperature range; ° C

Diluents

Ratio of diluent /

Feed; Mole / mole

Yield of liquid; Weight percent

Composition of the liquid reaction flow:
1,4-diazabicyclo [2.2.2] octane; Weight percent
Piperazine; Weight percent

Yield based on the charge:

1,4-diazabicyclo [2.2.2] octane; Weight percent

Weight percent of theory

1.2
371 to 377
benzene 0.41
385 to 391
N ₂ 1.22
343 to 360
no 1.42
363 to 382
no 4/1
96.4 3.5 / 1
84.5 93.3 92.7 36.8 43.4 19.9
1.9 27.9
2.4 35.3
41 36.7
42.6 18.5
21.5 25.8
30th

Claims (1)

14 4Ö 4ίβ Claim: Process for the preparation of 1,4-diazabicyclo [2.2.2] octane by passing gaseous over it N-Hydroxyäthylpiperazin over solid, acidic, silica-containing cracking catalysts, characterized in that the Reaction at 260 to 427 ° C with a space velocity of about 0.2 to 1.0 based on the volume of the N-Hydroxyäthylpiperazins measured as a liquid per unit volume of the Catalyst per hour in the presence of nitrogen or benzene as an inert diluent performs.