ZUSAMMENFASSUNG:Cycloocten wurde in Anwesenheit des Katalysatorsystems W C~G / C~H~O H / C~H~A~C I oligomerisiert mit dem Ziel, die homologe Reihe (&HI& darzustellen. Es wurden die Reaktionsbedingungen, besonders hinsichtlich der Katalysator-Konzentration, und der EinfluB des Losungsmittels untersucht. Die isolierten Oligomeren (Dimeres, Trimeres) wurden IR-, NMR-und massenspektrometrisch charakterisiert.
SUMMARY:Cyclooctene was oligomerized in the presence of the catalytic system WCls/C2H50H/ CaH5AlC12 in order to prepare the homologous series ( C E H~~)~. The conditions of reaction were established particularly with respect to the catalyst concentration. The influence of the solvent was investigated. The oligomers prepared (dimer, trimer) were characterized by IR, NMR, and mass spectroscopy.
The metathesis reaction of cycloolefines such as cyclooctene and cyclododecene in the presence of suitable catalysts yields a homologous series of oligomers besides the polymer. The oligomers have been proven to be the cyclic oligoalkenylenes2), e.g. the cyclic oligooctenylenes and oligododecenylenes.Ni(CN)24), Fe(C0)S or Mo(CO)~') results in high yields of the respective benzene derivative.On the other hand, it is known that alkynes are also able to yield metathesis products, as has been reported for 2-pentyne6) with heterogeneous disproportionation catalysts in the gas phase and for I-hexyne') with a homogeneous metathesis catalyst, the main products in the latter case, however, being cyclic trimers (benzene derivatives) and the polymer.According to an investigation of Dall'Asta et al. *) the formation of "apparent" metathesis products was considered to be a side reaction of the cyclotrimerisation of alkynes to aromatic hydrocarbons. A mechanistic concept corresponding to that of the metathesis of alkenes has been proposed by Katz et al.9). In this paper we report the reaction of cyclodecyne in the presence of a metathesis catalyst.The reaction of cycloalkynes with certain catalysts, e.g. 0,5.10~3mol (0,2g) WCI6 and an equimolar amount of ethanol were dissolved in 80 ml heptane. Then mol(1,4g) cyclodecyne were injected by means of a syringe. After 5min the reaction was started by adding 10-3mol C2H5A1Cl2 (10% solution in heptane) to the red solution which became turbid, a light-brown precipitate being formed. After 45min at room temp. (20°C) the reaction was terminated by addition of methanol. The yellow solution was decanted, residual catalyst particles were removed 3117
Die homologe Reihe der Oligomeren des Cyclooctens wurde mit Hilfe der Metathese‐Reaktion dargestellt; die Oligomeren wurden gelchromatographisch getrennt und gereinigt. Ihre Siedepunkte und Brechungsindices wurden bestimmt, und ihr spektroskopisches Verhalten wurde untersucht. Insbesondere werden die Massenspektren der Oligomeren im Vergleich zu denen der Oligomeren des Cyclododecens, des 1,5‐Cyclooctadiens und acyclischer Oligobutadiene diskutiert. Die Ergebnisse bestätigen die cyclische Struktur der durch ringöffnende Polymerisation von Cycloolefinen erhaltenen Oligomeren. Darüberhinaus wird gezeigt, daß die Massenspektrometrie unter geeigneten Bedingungen herangezogen werden kann, um zwischen cyclischen und acyclischen Kohlenwasserstoffen zu unterscheiden.
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