DE1231695B - Process for the preparation of dimers of bicyclo- [2, 2, 1] -heptadiene- (2,5) or their hydrogenation products - Google Patents

Description

Process for the preparation of dimers of bicyclo- [2,2,1J-heptadiene- (2,5) or their hydrogenation products. Addition to patent: 1 197083 According to patent 1 197 083 one can dimers and trimers of bicyclo- [2,2,1] -heptadiene- (2,5) or their hydrogenation products by treating the bicyclo- [2,2,1] -heptadiene- (2,5) at 0 to 180 "C, preferably at 60 to 120 ° C a catalyst in the form of a complex compound of iron, Added nickel or cobalt, in which the metal is of a low valence, preferably of valence level zero, as a central atom and at least partially organic electron donating - compounds act as ligands what one optionally the reaction products in a known manner catalytically, for. B. with Raney nickel at room temperature, hydrogenated.

As has been shown, these di- and trimers have a very high heat of combustion per volume unit.

For this reason they are of particular interest as a specialty fuel for jet planes and missiles that have a limited fuel capacity are. Although in many cases the dimer is already a liquid, does it have too high a freezing point of z. B. 0 to 20 0.C. The aim of the present invention is now the method according to patent 1: 197 083 to be modified in such a way that low-melting mixtures of dimers of bicyclo- [2,2,1] -heptadiene- (2,5) with melting points around 100 ° C.

In the process according to patent 1 197 083, there is essentially one Mixture of three isomers, which in the following correspond to their occurrence in the gas chromatograph are referred to as dimer I, dimer II or dimer III, with melting points from 67 to 68, 89 or -20 "C. In addition, a trimer is formed in smaller quantities with a melting point of 201 ° C.

Low-melting mixtures of dimeric bicycloheptadienes can be prepared from these pure components. These mixtures show a decreasing melting point with decreasing content of dimer I and increasing content of dimer III, as can be seen from the following data Dimers I 4 Dimers II 1 Dimers III Mp ° C Weight percent Mixture A .. 29.2 22.4 48.4 -15 Mixture B. . 13.5 27.3 59.2 ~ 75-75 Mixture C .. ........ 6.2 26.8 67.0 ~ -75 The experiments show that there is a considerable range of variation in the composition of such low-melting mixtures. In general, it can be said that low-melting mixtures are obtainable with a content of less than 20 percent by weight of dimer I and more than 40 percent by weight of dimer III.

It has now been found that such particularly low-melting Mixtures - obtained by modifying the process for making Dimers of bicyclo- [2,2,1] -heptadiene- (2,5) or of their hydrogenation products, by treating bicyclo- [2,2,1] -heptadiene- (2,5) with added complex compounds of iron, nickel or cobalt, in which these elements in a lower valence level are present, and the ligands are at least partially organic, represent electron donating compounds at temperatures from 0 to 180 "C and optionally catalytic hydrogenation of the reaction products according to Patent 1,197,083 applies, which is characterized in that the complex compounds of iron or cobalt and in a temperature range of 100 to 20,000, optionally under pressure, works.

Because the boiling point of bicycloheptadiene is 89.2, the The reaction is generally carried out in a closed vessel, in which the pressure depends mainly on the temperature. The reaction times are 5 minutes to 2 hours, preferably 1/2 hour. The method of the present invention works best carried out without a solvent, but optionally solvents such. B. aromatic hydrocarbons, can be used.

Catalysts are expediently used, which by mixing a Cobalt compound, but preferably an iron compound, in the presence of electron donating Compounds such as bicyclo- [2,2,1] -heptadiene- (2,5) itself or one of its dimers, with a reducing agent, e.g. B. an aluminum alkyl compound are. For the rest, reference is made to the remarks with regard to the preparation of the catalyst referred to in the description of patent 1,197,083, as well as the following Examples. The complex catalyst is preferably used in amounts from 0.1 to 1.5 Weight percent (based on bicycloheptadiene) used.

The dimeric mixtures of bicycloheptadiene prepared according to the invention are characterized by the high Content of dimeric bicycloheptadiene III with the boiling point from 76aC / 0, Zmm Hg. The large proportion of dimer III meets the requirement to a large extent Measures to produce> rocket propellants with a melting point of around 10,000.

By partial or complete hydrogenation of the dimeric mixtures If necessary, the melting point can be increased in a certain way.

Examples The dimerizations are carried out as follows: The calculated Amount of iron acetylacetonate is three fifths of the total involved in the reaction Amount of bicycloheptadiene dissolved, filtered and placed in an autoclave, which has a capacity of 4 times the volume of bicycloheptadiene.

After evacuation, the autoclave is heated to 80 ° C. in a water bath. The reducing agent (triethylaluminum), dissolved in the remaining amount of bicycloheptadiene, is pressed into the autoclave at 1.5 atm from a steel bomb. The pressure in the autoclave rises for seconds 3 at and then falls again to 0 at. The autoclave is then heated in an oil bath at a constant temperature for the specified time. The reaction product is distilled with the aid of a mercury diffusion pump. The results are shown in the following table, as well as the result of a Experiments 14 and 15 used triphenylphosphite-containing catalysts which were prepared by adding the appropriate amount of phosphite before the reduction. Experiment 6 catalyst | Reaction time j reaction ti | Yield | Melting point 1 I 15 minutes 10000 680f, -120 to 100 "C 2 F 10 30 minutes I00oC 6801o -120 to 100 "C 3 re ~~ to 1 / olg) 45 minutes 10000 72 ° / o -120 to 100 "C 60 minutes 10,000 72 ° / o 120 to 10,000 5} / generally f 15 minutes; 1000C 70 ° | <e -115 to 11000 6 FtF1G. 30 minutes 12000 7001o -115 to 110 ° C 6 (1 J5 30 minutes 120 "7401o -115 to 110 ° C 8 60 minutes 12000 77 olg -115 to 110 ° C 9 - / N f 10 minutes 150 "C 650 / o -120 to 10 ° C 10 Fe 30 minutes 15000 730 / o -120 to 110 "C 11½ \ 210 / oi 4 minutes 150 "C 750 / o -120 to 110 ° C 12 JX / 5 l 60 minutes 15,000 750 / o -120 to 110 "C 13 Fe 0ffi5 ° / Oig 15 minutes 100 ° C 800/0 - 80 "C 5 14 Fe lí to [l P (from 0 ^ 50 / o (o \ o>so'o 45 minutes 12000 41 weeks - - 80 "C IJ- 15 Co iiW; bP 0.5 weeks 30 minutes 17000 45 weeks -100 "C 3

Claims (1)

Claim: Modification of the process for the production of dimers of bicyclo- [2,2,1] -heptadiene- (2,5) or of their hydrogenation products Treating bicyclo- [2,2,1] -heptadiene- (2,5) with added complex compounds of iron, nickel or cobalt, in which these elements are in a lower valence level are present and the ligands are less at least partially organic, electron donating Represent compounds at temperatures from 0 to 180 "C and optionally catalytic Hydrogenation of the reaction products according to Patent 1197083, characterized in that the complex compounds of iron or cobalt are used and in a temperature range from 100 to 200 "C, if necessary under pressure, works.