3,088,959 United States Patent Office Patented May 7, 1963 1. 2 or grouping of carbon atoms which is present in cyclo 3,088,959 pentadiene. This grouping is illustrated as PROCESS OF MAKENG CYCLOPENTADEENY NECKEL, NTROSYL COMPOUNDS Robert D. Feltham, Joseph F. Anzenberger, azad Jonatian T. Carrie, Pittsburgh, Pa., assignors to The Interaa tional Nickel Company, Inc., New York, N.Y., a corpo ration of Delaware No Drawing. FiRed Sept. 1, 1960, Ser. No. 53,374 The substituent groups on the cyclopentadiene moiety 6 Clains. (C. 260-439) 0. indicated as R, R2, R3, R and R5 are any one or more The present invention relates to the production of of hydrogen atoms, halogen atoms and/or organic groups nickel compounds and, more particularly, to the produc such as aliphatic groups, aromatic groups, alicyclic groups, tion of nickel nitrosyl compounds containing a group etc. The substituent groups can also bond at two posi having the cyclopentadienyl moiety. tions. Where this occurs, groups can substitute for adja Compounds such as cyclopentadienylnickel nitrosyl, 5 cent R groups, e.g., Ra and R3 and/or R4 and R5 to form methylcyclopentadienylnickel nitrosyl and other complex indene and other condensed ring structures. nitrosyl compounds containing a cyclopentadienyl-type As mentioned hereinbefore, when carrying out the proc group have been made. Such compounds have use as ess of the present invention, the reactants are reacted in gasoline additives. When such use is contemplated, it is the presence of a base. The base can advantageously be economically imperative that the compounds be produced 20 a nitrogen base or a phosphorus base or an alkoxide of a in good yield from the most readily available and inex metal having a strong hydroxide. Nitrogen bases include pensive raw materials. A further desideratum is that ammonia, primary, secondary and tertiary amines, quater the process result in a product which can be readily sepa nary ammonium hydroxides and the heterocyclic nitrogen rated into usable fractions. Although attempts were made bases. Satisfactory nitrogen bases include ammonia, di to provide an industrially acceptable process, none, as far ethylamine, triethylamine, pyridine, di-n-butylamine, di as We are aware, was entirely successful when carried into ethanolamine, morpholine, tri-n-butyl-amine, triethylene practice commercially on an industrial scale. diamine, n-butylamine, piperidine and ethylenediamine. It has now been discovered that by means of a special Phosphorus bases include the alkyl substituted phosphines. process, nickel nitrosyl compounds containing a cyclo Examples of such phosphorus bases include triethyl phos pentadienyl-type group can be made in good yield from 30 phine and tri-n-butylphosphine. Examples of satisfactory comparatively inexpensive raw materials. alkoxides include sodium ethoxide, potassium isopro It is an object of the present invention to provide a poxide and cesium butoxide. novel process for the production of nickel nitrosyl com Because the reaction between the nickel carbonyl and pounds having a cyclopentadienyl-type group. nitric oxide is highly exothermic in nature, it is desirable Another object of the invention is to provide a novel 35 that the reaction be carried out in a liquid medium. The single stage process for the production of nickel nitrosyl medium should be a solvent for the reactants and inter compounds having a cyclopentadienyl-type group. mediates. It should have a high heat capacity and be The invention also contemplates providing a novel readily separable from the product and unused reactants. process for the production of cyclopentadienylnickel Advantageously, the medium should also be substantially nitrosyl. 40 inert with respect to the reactants, intermediates and/or Other objects and advantages will become apparent the products. In practice, however, these ideal character from the following description. istics are almost impossible to attain in a single medium. Generally speaking, the present invention is directed From the practical viewpoint, however, the reaction medi to a process for the production of nitrosyl compounds of um can be commercially available alcohol, for example, nickel which comprises subjecting a mixture of nickel 45 ethanol and methanol, an ether such as ethyleneglycoldi carbonyl, a base and a reaction medium to the action of methyl-ether, a high boiling point ester such as di-2- nitric oxide. Nickel nitrosyl compounds having the ethylhexyl adipate, or may be triethylamine. nickel covalently bonded to a group such as cyclopenta When carrying out the process of the present invention, dienyl and groups homologous thereto, e.g., methylcyclo care must be taken to exclude oxygen-containing gas pentadienyl, are produced in accordance with the present 50 from the reaction medium when nitric oxide is present. invention by forming a mixture of nickel carbonyl, a base Nitric oxide reacts with oxygen in air or other gas to form nitrogen dioxide. Nitrogen dioxide reacts with and and a reaction medium and thereafter adding cyclopenta destroys the cyclopentadiene-type nickel nitrosyl com diene or a compound homologous thereto and nitric oxide pound. Thus, the presence of nitrogen dioxide in the to the mixture. The cyclopentadiene (or cyclopentadiene 55 type compound) can be added either before, simultaneous reaction mixture serves to decrease the yield of the de with, or after the nitric oxide. Advantageously, when the sired product. nitric oxide is added, it is at a partial pressure of at least After nitric oxide has been introduced into the re about atmospheric pressure and more advantageously at action medium which advantageously contains the cyclo pentadiene-type compound, the amine and nickel car a partial pressure substantially above atmospheric pres 60 Se. bonyl, an initial reaction takes place wherein the reactants The terms “cyclopentadienyl-type' and "cyclopenta react to form a nickel nitrosyl intermediate compound. diene-type' are used to denote groups and compounds, This intermediate thereafter reacts to form the desired respectively, which contain the cyclopentadienyl group compound. Advantageously, by proper selection of the and groups homologous thereto. Cyclopentadiene-type copresent base, this reaction takes place almost imme compounds include all compounds which have the moiety diately. In certain instances, however, after all desirable 3,088,959 3 4. reaction with nitric oxide is completed, considerable time 23.2 parts by weight of nitric oxide in a pressure reactor. must elapse before the desired product is obtained. This The nickel carbonyl and methylcyclopentadiene are dis time of course depends, in at least part, upon the tem Solved in 158 parts by weight of absolute ethanol which perature at which the intermediate is maintained. On also contains 14.6 parts by weight of diethylamine. The the other hand, the rate of the initial reaction, all other mixture is maintained initially at room temperature. Two things being equal, is primarily dependent upon the minutes after nitric oxide is introduced into the reactor partial pressure of nitric oxide. In practice, the partial at 300 p.s. i. gage, an initial reaction is complete with pressure of nitric oxide should be high, preferably in the production of a green cloudy solution containing an excess of about 15 pounds per square inch (p.s.i.) (gage). intermediate. After a few hours, the solution turns red The nitric oxide should be present with respect to nickel O brown and contains 7.06 parts by weight of the desired carbonyl in a ratio in excess of about 2 to 1 in moles and product. The reaction produces a 42% yield based upon advantageously not greater than about 4 to 1 in moles. nickel carbonyl initially present. In ordinary practice, the cyclopentadiene-type compound should also be present in an amount in excess of one Example IV mole for mole with respect to nickel carbonyl. Thus, 5 Cyclopentadienylnickel nitrosyl is produced by reacting it is advisable to maintain the cyclopentadiene-type com 17 parts by weight of nickel carbonyl and 13 parts by pound present in a mole ratio of about 1.1 to 1 to 2 to 1 weight of cyclopentadiene with about 15.3 parts by with respect to the nickel carbonyl. Weight of nitric oxide in a pressure reactor. The nickel When carrying out the process of the present invention, carbonyl and cyclopentadiene are dissolved in 158 parts by advantageous results have been achieved when the re 20 Weight of absolute ethanol which also contains 20 parts action medium at the start of the reaction has been at by Weight of triethylamine. The mixture is initially at room temperature. The reactions are exothermic and, ac room temperature. One and one-half minutes after nitric cordingly, the temperature rises while carrying out the oxide is introduced at 200 p.s. i. gage, a green, clear liquid process. Care should be taken that the temperature not is obtained. This liquid turns red on standing and con be allowed to go so high that thermal decomposition of 25 tains a Substantial amount of cyclopentadienylnickel the desired product occurs. nitrosy. In carrying the invention into practice, advantageous Example V results have been attained when cyclopentadiene is re acted batchwise in a pressure autoclave with nickel car Cyclopentadienylnickel nitrosyl is produced by dissolv bonyl and nitric oxide in the presence of diethylamine 30 ing 4.5 parts by weight of diethylamine and 6.6 parts by and absolute ethanol. The useful product in this in Weight of nickel carbonyl in 158 parts by weight of abso stance is cyclopentadienylnickel nitrosyl. Yields of cyclo lute ethanol. The mixture is placed in a suitable vessel pentadienylnickel nitrosyl of the order of greater than and is purged with nitrogen. Nitric oxide at substantial about 85% based upon the amount of nickel carbonyl ly atmospheric pressure is then bubbled through the mix present have been achieved. Cyclopentadienylnickel ni 35 ture for 150 minutes while the mixture is held at room trosyl is readily separated from the alcohol, the amine temperature.