United States Patent Patented Feb
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3,079,235 United States Patent Patented Feb. 26, 1953 1 2 gen at a temperature between 80 and 150° C. and under $379,235 METHGD @F PREPARWG METAL‘LEC NECKEL pressure between 40 and 60 atm., resulting in active nickel AND NECKEL CAREQNYL suitable as a catalyst for certain hydrogenation processes. Ibrahim Dakii, Busto Arsizio, and Luigi Corsi, Milan, The hydroxide reduction under these conditions requires Italy, assignors to Monteeatini Soot-eta Generals. per 6 hours to be completed. l’i'ndustria Mineraria e Chimica, Milan, Eta‘iy, a corpo We have now found that, if operating in the presence ' ration of Italy ' ' of sulfides, this reduction proceeds catalytically and is N0 Drawing.‘ Filed Nov. 27, 1956, 5th‘. No. 624,522 completed in about 30 minutes at 140° C. under a hy ; ‘Claims priority, application Italy Dec. 2, 1955 drogen partial pressure of 30 atm. At higher tempera 16 Claims. (Ci. 23--2tl3) tures and pressures the time required is still less. More This invention relates to a new method of preparing over, the catalyst concentration in?uences the redutcion nickel carbonyl. rate to a substantial degree. For example, at a molar Numerous methods for preparing nickel carbonyl are ratio of Ni:Na2S=10:1, operating at 140° C. and under in existence. Some of them, such as the Mond process a hydrogen partial pressure of 40 atm., the reduction is of purifying raw nickel, are based on reactions between 15 completed in about 25 minutes while, under the same con gas and metallic nickel in the dry state, while others are ditions, but using a molar ratio of Ni:Na2S=20:1 the based on reactions between gas and solutions or sus reduction requires 1 hour. pensions of nickel compounds. The aqueous suspension of ?nely divided reduced nickel The process using nickel oxide as an intermediate re obtained in this manner, can be directly used for the quires, in the ?rst place, some preliminary operations in 20 preparation of nickel carbonyl. As an alternative the order to convert other nickel compounds into nickel suspension can be ?rst ?ltered. The ?nely divided n’ckel oxide. Subsequently thereto, these processes require high obtained in this manner is particularly active and reacts temperatures, about 300-400° C., and long reduction already at room temperature with carbon monoxide un periods in order to produce reduced nickel from the der a pressure of 10 atm. The carbonylation rate ir1— oxide. As a compensation, the process requires only mod 25 creases quickly at higher carbon monoxide pressure. erate temperatures and pressures for the carbonylation vFor example, if a suspens’on of nickel hydroxide reduced reaction between reduced nickel and carbon monoxide. in the presence of sodium sul?de at a molar ratio of The other processes, starting from nickel salts solu Ni:Na2S=l0:l is treated with carbon monoxide at 55° tions or nickel hydrox'de suspensions, are more simple as C. at 25 atm. the reaction is completed in 4 hours, at 45 far as the process steps are concerned, but require much atm. in 50 minutes, at 70 atm. in 35 minutes and at 140 more drastic operating conditions. Thus, the conversion atm. in 17 min. At low carbon monoxide pressures, the of the Ni(CH3)6Cl2-cornplex into nickel tetracarbonyl in?uence of temperature on the carbonylation is negative, by treatment with carbon monoxide requires temperatures that is the reaction rate decreases by increasing the tem of 80~l70° C. at a pressure of 50-200 atm. and in perature. The Ni:Na2S ratio also in?uences the carbon volves serious problems of selecting equ'pment that is 35 ylation rate, especially when low partial pressures of resistant to the reactants at the required reaction condi carbon monoxide are used. tions. According to other disclosures concerned with The reactions involved in this process (assuming that nickel carbonyl hydroxide, a conversion catalyzed with the starting Ni(OH)2 is prepared from NiCl2) are as alkali sul?des or cyanides, by means of reacting directly follows: with carbon monoxide occurs under relatively drastic 40 temperature and pressure conditions, such as at tem peratures above 60° C. and at a pressure in excess of N MOB) z-i-Hz Nl+2H2O ?rst stage 50 atm. However, even at a temperature above 80° C. sul?de catalyst and a pressure higher than 50 atm., the reaction is slow Ni+400 _-————> Ni (CO)4 second stage and requires at least twenty hours; while at 40° C. it is 45 so slow that it is not suitable for commercial practice. In the direct reaction between nickel hydrox’de and carbon monoxide, for every mol of nickel tetracarbonyl sul?de catalyst formed, one mole carbon dioxide is obtained which, in Ni-l-4GO -—--——-> Ni (00% second stage the subsequent stage of recovering nickel carbonyl, would 50 cause some dii?culties and, therefore, must be removed Instead of the chloride, any organic or inorganic nickel either by washing with water or by treatment wIth alka sal-t can be used, provided that it is not the salt of a lies. In both cases the consumption of energy and re strongly oxidizing acid. Instead of sodium hydroxide, action materials is rather high and intricate equipment any other alkali or earth alkali base can be used while, is required. 55 in lieu of hydrogen and carbon, monoxide, mixtures of Now we have found and this is the object of the pres both gases or gases containing them can be used. ent invention, that, if the reduction of nickel hydroxide Both reduction and carbonylation reactions can be car and the carbonylation of the ?nely divided nickel sus ried out in one or in two different reactors. The latter pension thus obtained are carried out in separate stages, is preferable because the two phases have di?erent op the carbonylation is performed without the presence of timum conditions. practically any CO2, because CO2 cannot form at the As previously mentioned, contrary to the prior proc ?rst stage due to the reducing action of hydrogen which esses for preparing nickelcarbonyl from a nickel hydrox is being used, or the CO2 is readily discharged after the ide suspension, in the herein claimed carbonylation reac ?rst stage if the reduction is carried out with carbon tion the carbon dioxide formation is limited only to monoxide. 65 traces. This simpli?es substantially the recovery of nick According to the present invention a catalyst is used elcarbonyl, because at room temperature and ordinary consisting of an organic or inorganic sul?de, such as pressure, one liter CO2 entrains one liter of nickel car Nags, CS2 or barium sul?de, which permits to operate at bonyl vapors. The reaction rate is not in?uenced by the moderate temperatures and pressures, at least during the concentration of the nickel suspension and, therefore, second stage of carbonylation. 70 diluted or concentrated suspensions can be employed; It is known that an aqueous suspension of nickel hy for example, operations with suspensions containing 15% droxide puri?ed by washing can be reduced with hydro nickel can be performed without any inconvenience. ' 3,079,235 3 4 The process can be carried out either as batch or con NaOH and employing barium m'onosul?de (7 parts 13218), tinuous process. as catalyst. The reduction is carried out at 200° C. for The following examples are presented to illustrate but ?fteen minutes under a hydrogen partial pressure of 30 in no way to limit the present invention: atm. and the carbonylation at 55° C. for forty-?ve min Example 1 utes under a CO partial pressure of 45 atm. Conversion is 90.1% . 125 parts NiClz, 275 parts water, 155 parts of a 30% Example 7 NaOH solution and 5 parts Nags are charged into a re— actor provided with a blade stirrer and electrically heated The process is carried out as in Example 1 but starting with 125 parts nickel chloride, 275 parts water, 150 parts from outside. ‘ After carefully displacing the air in the 10 reactor with hydrogen, the mixture is heated to 135 NaOH and using 2 parts carbon disul?de as a catalyst. ‘140" C. and hydrogen gas of'70 atm. is introduced. A The mixture is reduced with hydrogen at 160° C. under quick decrease of pressure is almost immediately noted a hydrogen partial pressure of 40 atm.; reduction time ‘which shows the commencement of Ni(Ol-I)2 reduction twelve minutes. The carbonylation is carried out as 55° C. under a CO pressure of 45 atm.; carbonylation to metal nickel. The reduction is completed after 17 15 minutes. After cooling, unreacted hydrogen is dis time 47 minutes. Conversion 92.8%. charged, the temperature is brought to 100° C. and Example 8 carbon monoxide of 140 atm. is introduced. The car ‘bonylation reaction starts immediately and is completed The process is carried out in the apparatus of Example after 17 minutes. 20 1. 125 parts nickel chloride, 275 parts water, 145 parts The conversion of nickel hydroxide to nickelcarbonyl NaOH and, as a catalyst, 2.5 parts sodium sul?de are is 88.4% while the yield, based on the converted product, employed. The reduction is carried out with CO at ‘is almost quantitative. In theexhaust gases the presence 200° C. in two stages in order to remove CO2 from the of carbon dioxide is not noted. autoclave. During the reduction the CO partial pressure 25 is 30 atm. The carbonylation is carried out at 52° C. Example 2 under a CO pressure of 45 atm. The conversion yield is 125 parts‘ NiClz, 275 parts water, 185 parts 30% NaOH 72.4%.