2,987,529 United States Patent Office Patented June 6, 1961 2 materially lower carbon monoxide pressure for a given 2,987,529 temperature and reaction or, conversely, the temperature USE OF TRANSTON METAL CARBONY LS IN THE MANUFACTURE OF CYCLOPENTADENYL can be lowered and/or increased rates can be obtained MANGANESE TRICARBONY, with the same or only moderately lower carbon monoxide Leslie L. Sims, Baton Rouga, La., assignor to Ethyl Cor pressures. poration, New York, N.Y., a corporation of Delaware The catalytic activity of metal carbonyls in the process No Drawing. Fided Apr. 25, 1958, Ser. No. 730,786 of this invention is completely unexpected and unpredict 3 Claims. (C. 260-429) able. At the same time, the effectiveness of these cata lysts is very pronounced and the resulting advantages are This invention relates to the manufacture of cyclopenta O extremely important from a commerical standpoint. The dienyl manganese compounds and more particularly to reason for the catalytic activity of these metal carbonyls the manufacture of cyclopentadienyl manganese tricar is not understood. However, it is apparent that their bonyl compounds. activity is not due to carbonylation of the manganese Cyclopentadienyl manganese tricarbonyl compounds by the carbonyl groups of the metal carbonyl. In fact, have been found to be exceptionally effective antiknocks 5 in the absence of gaseous carbon monoxide the rate of for use in fuels for spark plug ignition internal combus reaction is considerably slower than with gaseous carbon tion engines. These compounds not only have excep monoxide alone and the overall product yield is ma tional effectiveness as antiknocks but also many of these terially less than in the process of this invention. It also compounds have auxiliary properties which make them might be theorized that the transition metal carbonyl is practical and desirable for commercial use. These aux 20 converted to the corresponding metal cyclopentadienyl iliary properties include high solubility in fuels, such as compound. However, this is unlikely since, in the case of gasoline, and thermostability either alone or in gasolines iron carbonyls, ferrocene would be produced which is a which makes these compounds entirely satisfactory for highly stable and a relatively inert material. Moreover, use under the widely varying conditions to which gasoline neither ferrocene or the mixed compound dicyclopenta and other fuels are normally subjected. Possibly of even 25 dienyl diron tetracarbonyl are effective catalysts. greater importance these compounds do not tend to form The actual rate of carbonylation of cyclopentadienyl any appreciable deposits on the engine pistons, valves and manganese compounds in the presence of transition metal spark plug surfaces and likewise are not abrasive to the carbonyls is increased 100 percent or more and, at the engine parts as are characteristic of iron compounds. same time, the reaction can be conducted at materially It is accordingly an object of this invention to provide 30 lower temperatures. In addition, the transition metal car an improved process for the manufacture of cyclopenta bonyls even improve the yield of the desired cyclopenta dienyl manganese tricarbonyl compounds. Another ob dienyl manganse tricarbonyl product. For example, in jects is to provide a process of the above type having an carbonylating bis(cyclopentadienyl) manganese in con exceedingly fast reaction rate and capable of operation trolled experiments using about 700 pounds of carbon at relatively low temperatures and carbon monoxide pres 35 monoxide pressure, the manganese compound was com sure. Still another object is to provide a process which pletely carbonylated in about 1% hours, using 5 mole gives improved yield of the desired product. Another percent of iron pentacarbonyl (Fe(CO)5), whereas from object is to provide a process which has a high throughput 2% to 4/2 hours were required in the absence of iron per unit quantity of reactor space and which is adapted to pentacarbonyl. Moreover, the reaction with iron car employ simple and economic process equipment. Other 40 bonyl had an excellent rate of reaction at temperatures objects and advantages of the invention will be more ap above about 100° C. whereas no appreciable carbonyla parent from the following description and appended tion took place at temperatures below about 150 to claims. 155 C. without the iron pentacarbonyl. Moreover, the It has now been found that cyclopentadienyl manga yield of cyclopentadienyl manganese tricarbonyl with nese tricarbonyl compounds can be produced in excellent 45 the iron pentacarbonyl was 77.5 percent, compared to yields by reacting cyclopentadienyl manganese com only 74.5 percent when no iron carbonyl was employed. pounds with carbon monoxide in the presence of metal In carrying out the process of this invention, it is gen carbonyls, particularly transition metal carbonyls, pref erally desirable to employ a solvent, preferably an ether, erably employed in catalytic quantities. Most preferred which has a boiling point above the operating tempera are carbonyls of metals having an atomic number rang 50 ture of the reaction, or at least, which exerts a vapor ing from 24 to 28 inclusive, specifically chromium manga pressure which is less than about 50 percent of the carbon nese, iron, cobalt and nickel. By a transition metal is monoxide pressure. meant metals of group V-B, VI-B, VII-B, and VIII of The liquid media suitable for the process of this in the periodic table (Handbook of Chemistry and Physics, vention can be any solvent or complexing agent for the 36th ed., pp. 392 and 393). 55 manganese compound. In general, suitable solvents are More specifically, the process of this invention com ethers, amines, amides, nitriles, and the like. The ethers prises reacting a cyclopentadienyl manganese compound, can be either aliphatic or aromatic, such as dimethyl e.g. a bis(cyclopentadienyl) manganese compound or a ether, diethyl ether, methylethyl ether, anisole, diphenyl cyclopentadienyl manganese salt with carbon monoxide ether and, in general, any ether which is liquid at the gas, preferably in a liquid media which is a solvent for 60 reaction temperature and pressure employed. Preferred the cyclopentadienyl manganese compound, in the pres ethers are the cyclic ethers and the ethylene glycol type ence of from about 0.01 to 30 mole percent of a transi. ethers. Typical examples are dioxane, tetrahydrofuran, tion metal carbonyl at a temperature of from about 0° to ethylene glycol dimethyl ether, and corresponding higher 250° C., preferably from about 75 to 200° C. The alkyl ethers, such as diethyl, methyl ethyl, dibutyl, and cyclopentadienyl radical is a cyclomatic radical having a 65 the like. Typical examples of diethylene glycol dialkyl 5-carbon ring corresponding to the ring in cyclopenta ethers are the dimethyl, diethyl, methyl ethyl, dibutyl diene itself. Generally, carbon monoxide pressure rang and the triethylene glycol ethers including the dimethyl, ing from subatmospheric to superatmospheric, i.e. 2,000 diethyl, diisopropyl, and the like. In general the pre atmospheres, can be employed but usually pressures of ferred ethylene glycol dialkyl ethers have alkyl groups from about 25 p.s.i.g. to 5,000 p.s.i.g. are preferred. 70 containing from 1 to 6 carbon atoms. The presence of the transition metal carbonyl permits Suitable amine solvents for use in this invention are 2,987,529 3 4. propyl amine, diethyl amine, di-n-propyl amine, dibutyl pentacarbonyl was employed during the carbonylation re amine, triethyl amine, triisopropyl amine, and other action. In contrast to the process using iron pentacar amines having from 2 to 10 carbon atoms per alkyl group. bonyl, no appreciable reaction took place until the re Aromatic amines are also suitable, such as aniline, methyl action mixture had reached the reaction temperature of aniline, dimethyl aniline, trimethyl aniline, and similar 5 165 C. and the carbon monoxide absorption was ma compounds. A particularly suitable amine solvent is di terially lower than when using the iron carbonyl, i.e. the cyclohexylamine. yield was less than 75 percent. Typical examples of suitable amides are formamide, The bis(cyclopentadienyl) manganese was prepared by and the mono- and dialkyl formamides, such as N,N-di reacting sodium metal with cyclopentadiene monomer methyl formamide, containing alkyl groups having from 10 (15 percent excess) in diethylene glycol dimethyl ether 1 to 6 carbon atoms. Other suitable amides are cyclic solvent at 110° C. The reaction mixture was stirred dur amides, such as N-methyl pyrrollidone and other alkyl ing reaction until there was no evidence of further hydro pyrrollidones and amides of inorganic acids, such as hexa gen evolution. This reaction mixture was then reacted methyl phosphoramide. with anhydrous manganous chloride (1.1 mole equivalents Suitable nitriles which can be employed as solvents in 15 of manganous chloride) at reflux temperature (160-165 this invention are acetonitrile, propionitrile, butyronitrile C.) The reaction mixture was again stirred throughout and the like. this reaction and the reaction product was filtered to re The liquid media can be employed in a wide range of move the inorganic salts. The bis(cyclopentadienyl) concentration from about 0.5 mole, based upon the man manganese product in diethylene glycol dimethyl ether ganese compound, to about 30 moles. Higher dilution 20 was then carbonylated in accordance with the above pro of the reaction mixture can be employed except that no cedure. appreciable improvement in the reaction is obtained and Example II considerably greater difficulty is encountered in the re Example I was repeated except that bis(methylcyclo covery of the desired product. pentadienyl) manganese was carbonylated using only 3 The compounds which can be made by the process of 25 mole percent of iron pentacarbonyl. In this case the prod this invention are any cyclopentadienyl manganese tri uct was methylcyclopentadienyl manganese tricarbonyl. carbonyl compounds, including substituted cyclopenta The maximum reaction pressure of carbon monoxide was dienyl compounds, such as the indenyl and fluorenyl 350 p.s.i.g. and the minimum reaction pressure was 300 derivatives. Typical examples of such compounds are p.s.i.g., 66 percent completed in 30 minutes. Virtually cyclopentadienyl manganese tricarbonyl, methylcyclo- 30 the same reaction rate increase was obtained in this run pentadienyl manganese tricarbonyl, n-butylcyclopenta as in Example I and again a material increase in yield of dienyl manganese tricarbonyl, isobutylcyclopentadienyl desired product is obtained, that is, 83 percent yield using manganese tricarbonyl, n-decylcyclopentadienyl man iron pentacarbonyl as compared with only about 72 per ganese tricarbonyl, phenylcyclopentadienyl manganese cent yield in the absence of iron pentacarbonyl. tricarbonyl, methylphenylcyclopentadienyl manganese 35 In this run the bis(methylcyclopentadienyl) manganese tricarbonyl, indenyl manganese tricarbonyl and fluorenyl was produced by reacting sodium in diethylene glycol di manganese tricarbonyl. For fuel use, the preferred com methyl ether with methylcyclopentadiene dimer at a tem pounds are those containing up to about 12 carbon atoms perature of about 190° C. This reaction product con in the cyclopentadienyl group. ?taining methylcyclopentadienyl sodium was thereafter re The following are typical examples of the present in- 40 acted with the manganous chloride in accordance with vention and are given for the purpose of illustration and the procedure given above for the manufacture of bis not a limitation. In these examples, all quantitative units (cyclopentadienyl) manganese. are in parts by weight. Example I 45 Example III Bis(cyclopentadienyl) manganese dissolved in a molar Example I is repeated except that a total of only 0.5 equivalent of diethylene glycol diethyl ether was placed mole percent of iron pentacarbonyl is added to the reactor in a pressure reaction vessel provided with a stirrer. To and this added in three equal portions beginning with an this solution was added 5 mole percent (based on bis initial charge and two additional charges at 30-minute in (cyclopentadienyl) manganese) of iron pentacarbonyl. 50 tervals. The cyclopentadienyl manganese tricarbonyl pro Carbon monoxide was fed to the reactor giving a pres duced is recovered in excellent yield. Sure of 610 p.s.i.g. The reaction mixture was then heated Example IV from room temperature up to 165 C. At about 100 C. the carbon monoxide pressure in the reactor began Example I is repeated except that bis(n-butylcyclo to decrease, indicating an initiation of the carbonylation 55 pentadienyl) manganese is reacted in the presence of 3 reaction. Upon attainment of a temperature of 165 C., moles of tetrahydrofuran instead of the glycol ether sol the carbon monoxide pressure had already fallen to 525 vent and the reaction is conducted at 50° C. using 1000 p.s.i.g., a drop of almost 400 p.s.i.g. from the calculated p.s.i.g. carbon monoxide pressure. Cobalt carbonyi is maximum reaction temperature pressure of 915 p.s. i.g. employed instead of the iron carbony1. The reactor was then repressurized to 750 p.s.i.g. (at re- 60 The n-butylcyclopentadienyl manganese tricarbonyl is action temperature) and the reaction continued for a recovered by distillation. period until the pressure had again decreased to 650 Example V p.s.i.g. The reactor was then repressurized to 750 p.s. i.g. Several times in like manner. The reaction was complete Methylcyclopentadienyl manganese chloride is reacted after about 1/2 hours, indicated by an absence of fur- 65 with carbon monoxide (350 p.s.i.g.) at 125 C. in diethyl ther pressure drop. The crude reaction mixture was ene glycol diethyl ether in the presence of nickel carbonyl. thereafter fractionated at reduced pressure to remove the Similar results are obtained except that methylcyclopenta diethylene glycol dimethyl ether from the cyclopentadi dienyl manganese tricarbonyl is formed. enyl manganese tricarbonyl product. The yield of cyclo pentadienyl manganese tricarbonyl was 77.5 percent, 70 Example VI based upon the bis(cyclopentadienyl) manganese. Example I is repeated except that manganese pentacar The above product, after repurification by distillation, bonyl dimer is employed in place of the iron carbonyl is used as an antiknock in accordance with the procedures and the reaction is conducted in cyclopentadiene dimer given in U.S. Patent 2,818,417. at a temperature of 150 C., using 500 p.s.i.g. of carbon The above reaction was repeated except that no iron 75 monoxide. Similar results are obtained. 2,987,529 5 6 Example VII bon monoxide in the initial presence of nickel metal which Example III was repeated except that bis(n-decylcyclo forms the nickel carbonyl under reaction conditions. The pentadienyl) manganese is reacted with 800 p.s.i.g. of reaction is conducted in diethylene glycol diethyl ether carbon monoxide at 80 C. in 10 moles of toluene. A Solvent at 150 C. chromium carbonyl is employed using a catalyst in place I claim: of the iron carbonyl. The n-decylcyclopentadienyl man 1. A process for the manufacture of a cyclopentadienyl ganese tricarbonyl is recovered in good yield. hydrocarbon manganese tricarbonyl comprising reacting a bis(cyclopentadienyl hydrocarbon) manganese with car Example VIII bon monoxide while in contact with from about 0.01 to Example I is repeated in which bis(indenyl) manganese 10 about 30 mole percent of an inorganic transition metal is reacted with carbon monoxide (4500 p.s.i.g.) in the carbonyl, said transition metal being selected from the presence of 25 mole percent of vanadium carbonyl. The group consisting of groups V-B, VI-B, VII-B and VIII reaction is conducted in dimethyl ether solvent (4 moles of the periodic table, said carbon monoxide being main per mole of the bis(indenyl) manganese compound) at a tained at a pressure of from about 25 p.s.i.g. to about temperature of 0° C. The indenyl manganese tricarbo 5 2,000 atmospheres. nyl is recovered from the crude reaction product in good 2. The process of claim 1 wherein the process is con yield. ducted in a solvent at a temperature of from 0 to 150 C. Example IX 3. The process of claim 1 wherein the transition metal Bis(fluorenyl) manganese is reacted with carbon mon carbonyl is an iron carbonyl. oxide (300 p.s.i.g.) using niobium carbonyl as a catalyst. 20 This reaction is conducted in dicyclohexylamine solvent References Cited in the file of this patent (0.1 mole) at 190° C. The fluorenyl manganese tricar UNITED STATES PATENTS bonyl is recovered by distillation at reduced pressure. 2,557,744 Hurd ------June 19, 1951 Example X 25 2,748, 167 Hagemeyer et al. ------May 29, 1956 Bis(2,4-methylphenylcyclopentadienyl) manganese is 2,810,736 Catlin et al. ------Oct. 22, 1957 reacted with carbon monoxide (2000 p.s.i.g.) to form 2,4- 2,818,417 Brown et al. ------Dec. 31, 1957 methylphenylcyclopentadienyl manganese tricarbonyl. 2,870,180 Kozikowski et al. ------Jan. 20, 1959 This reaction is carried out using 2 mole percent (based 2,898,354 Shapiro et al. ------Aug. 4, 1959 upon the manganese compound) of molybdenum carbonyl 30 2,916,506 Axtell et al. ------Dec. 8, 1959 as a catalyst. The reaction is conducted in diethylene glycol dibutyl ether solvent at a temperature of 170° C. OTHER REFERENCES Deming: "General Chemistry, 5th edition, New York, Example XI 35 John Wiley & Sons, Inc., copyright 1944, last page relied Bis(cyclopentadienyl) manganese is reacted with car O