CH507309A - Preparation of pi-allyl nickel halides - Google Patents

Abstract

Process for the preparation of pi--allyl nickel halides comprises reacting nickel carbonyl and allyl halides, the CO formed during the reaction being removed from the reaction mixture as quickly as possible. Very low yields of pi--allyl Ni halides are normally obtained by reacting Ni carbonyl with allyl halides, such as allyl chloride, metallyl chloride, or crotyl bromide. Removal of the CO from the reaction mixture as rapidly as possible gives almost quantitative yields of the pi-allyl Ni halides. The products are used for the prepn. of catalysts.

Description

  

  
 



  Process for the preparation of z-allyl nickel halides
It is known that allyl halides, e.g. B. allyl chloride, allyl bromide, allyl iodide, methallyl chloride, crotyl chloride and crotyl bromide react with nickel carbonyl to form = c-allyl nickel halides (EO Fischer and 0. Bürger, Zt. Für Naturforschung, 16b, 77 [1961] and Chem. Ber. 94, 2409 [1961]). In these processes described so far, however, the yields of? R-allyl nickel halides are only about 100 / o d. Th.



   In order to improve the yield of these interesting compounds, it has also become known that α-alylnickel halides can be prepared by the reaction of olefin-nickel (O) complexes with allyl halides (DBP 1 194 417 of the Studiengeselischaft coal).



  In the process, although the α-AIIylnickelhaloge- nide in practically quantitative yield, but the necessary for the reaction olefin-nickel (O) complexes must previously by reaction of nickel compounds in the presence of suitable as electron donors olefins with organometallic compounds such . B. aluminum alkylene, who produced the.



   It has now been shown, surprisingly, that z-allyl nickel halides can be prepared from nickel carbonyl and allyl halides in practically quantitative yield if it is ensured that this is done according to the following scheme
EMI1.1
 carbon oxide formed is removed from the reaction mixture as immediately as possible to the extent of its formation. In the processes described so far, although normal pressure was used, the carbon oxide concentration remained so high as a result of the process conditions that it was possible via the formation of additive products (E. W. Gowling and S. F. A. Kettle, Anorg.

  Chem. 3, 604 [1964]) of carbon oxide with the resulting sr-allylnickel halide could lead to insertion reactions, as z. B. by R. F. Heck, Am. Soc. 85, 2013 (1963). The insertion products then react in a known manner with the formation of acid chlorides and the deposition of metallic nickel according to the following scheme:
EMI1.2

These undesirable side reactions can now be prevented according to the invention.



   The invention relates to a process for the preparation of Jc-allyl nickel halides of the formula
EMI2.1
 where R1 to R are hydrogen, alkyl, cycloalkyl, aralkyl or aryl, two adjacent of these radicals can also be connected to one another to form a ring system, by reacting nickel carbonyl with corresponding allyl halides, characterized in that the CO formed in the reaction is im The extent of its formation is continuously removed from the reaction mixture. It can do this in a simple manner, for. B. can be effected by blowing an inert gas stream through the reaction mixture, or by continuously pumping off the CO by applying a suitable vacuum, or by using these two measures in combination.



   Both chlorides, bromides and iodides can be used as allyl halides.



   The substituents Rt and R2 can be closed to form rings with the substituents R4 or R5. The substituents Rl or R2 or R4 or



  R, be linked to the substituent R3 to form a cyclic system. The substituents R1 and R2 or R4 and R3 can also be closed to form a ring.



   The reaction between allyl halide and nickel carbonyl can be carried out at temperatures from 0 to 1500 ° C., preferably at temperatures from 20 to 70 ".



   Aliphatic saturated hydrocarbons, aromatic hydrocarbons, dialkyl ethers or cyclic ethers and also alkylaryl ethers are used as solvents. If appropriate, halogenated aromatics and aliphatic alcohols can also be used as solvents.



   The reaction is preferably carried out at normal pressure. The inert gas is preferably the purest nitrogen or purest argon blown into the reaction mixture. In any case, it must be ensured that discharged nickel carbonyl is condensed out of the gas stream leaving the apparatus and can be returned to the reaction mixture.



   The a-allyl nickel halides which can be prepared according to the invention are, for. B. suitable for the production of highly active catalysts (see Belg. Pat. 351 596 of the coal study society).



   example
40 ccm = 0.31 mol Ni (CO) 4 are brought to the boil under argon with 700 ccm ether. Argon is passed into the solution through a frit. Ni (CO) 4 and ether are condensed in a low temperature cooler (-78) and returned to the reaction vessel.



  A mixture of 30 cc = 0.34 mol of allyl bromide and 50 cc of ether is added dropwise within 20 minutes. The initially colorless solution turns deep red. The reaction mixture is refluxed for one hour while argon is passed through. The resulting CO is blown off together with the argon via the top of the cryogenic cooler. The still warm solution is filtered through a G-3 frit, the filtrate is concentrated at 0.1 torr to about V3 and cooled to -80 ". The allyl nickel bromide crystallizes out in the form of deep red needles G-1 frit lifter removed and the crystals dried at 10-4 Torr and room temperature.Yield: 46.5 g = 83.6 / o d.

  Nickel analysis: Ber. 32.6 / o, found 32.4 / o.



   If the mother liquor is worked up, the α-allyl nickel bromide is obtained in a practically quantitative yield.

 

Claims (1)

PATENT CLAIM Process for the preparation of z-allyl nickel halides of the formula EMI2.2 where Rt to Rw are hydrogen, alkyl, cycloalkyl, aralkyl or aryl, two adjacent of these radicals can also be connected to one another to form a ring system, by reacting nickel carbonyl with corresponding allyl halides, characterized in that the CO formed in the reaction is im The extent of its formation is continuously removed from the reaction mixture. SUBCLAIMS 1. The method according to claim, characterized in that one works under normal pressure and blows the purest nitrogen or purest argon through the reaction mixture. 2. The method according to claim, characterized in that it is carried out in a solvent. 3. The method according to claim, characterized in that the removal of the CO is carried out by means of generating a vacuum and optionally simultaneous passage of an inert gas.