Nickel-carbonyl

LABORATORY CHEMICAL SAFETY SUMMARY NICKEL CARBONYL  

Physical Properties Colorless liquid bp 43 °C, mp -25 °C Very slightly soluble in water (0.0018 g/100 mL at 20 °C) 

Major Hazards High acute toxicity possible human carcinogen (OSHA select carcinogen ) highly flammable. 

Flammability and Explosibility Nickel carbonyl is a highly flammable liquid (NFPA rating = 3) that may ignite spontaneously and explodes when heated above 60 °C. Its lower flammable limit in air is 2% by volume the upper limit has not been reported. Carbon dioxide, water, or dry chemical extinguishers should be used for nickel carbonyl fires. 

In the presence of air, nickel carbonyl forms a deposit that becomes peroxidized and may ignite. Nickel carbonyl is incompatible with mercury, nitric acid, chlorine, and other oxidizers, which may cause fires and explosions. Products of decomposition (nickel oxide and carbon monoxide) are less toxic that nickel carbonyl itself. 

Analytical Methods and Speclatlon Electrothermal atomic absorption spectrophotometry (ETAAS), differential pulse adsorption voltammetry (DPAV), isotope-dilution mass spectrometry (ID-MS), and inductively coupled plasma mass spectrometry (ICP-MS) furnish the requisite sensitivity for measurements of nickel concentrations in biological, technical and environmental samples (Aggarwal et al. 1989, Case et al. 2001, Stoeppler and Ostapczuk 1992, Templeton 1994, Todorovska et al. 2002, Vaughan and Templeton 1990, Welz and Sperling 1999). The detection limits for nickel determinations by ETAAS analysis with Zeeman background correction are approximately 0.45 jg for urine, 

1 pg for whole blood, 50 ng L for serum or plasma, and 10 pg kg (dry wt) for tissues, foods, and feces (Templeton 1994). DPAV analyses using a dimethylglyoxime-sensitized mercury electrode provide detection limits of approximately 50 ng L for nickel determinations in whole blood, urine, saliva. 

The Ni contents of the four fractions are determined by ETAAS. Vincent et al. (2001) used a similar approach based on differential step-wise leaching of nickel from aerosol particles that had been fractionated with a cascade impactor. For fractionation of nickel species in natural waters, Mandal et al. (2002) used Chelex-100 as a competing ligand to measure the rate of Nk released by dissociation of nickel in dissolved organic carbon complexes. 

ANIMAL CARCINOGEN, SEVERE POISON, HIGHLY FLAMMABLE 

Explosive limits, above 2% flash point, below -20°C lower flammable limit, 2%.2 

Slightly soluble in air-free water soluble in alcohol, benzene, chloroform, acetone, and carbon tetrachloride. Oxidizes in air.1 

Bromine. Explosive interaction in liquid state.4 Dinitrogen Tetroxide. Interaction of the two liquids is rather violent.5 Mercury and Oxygen. A mixture of the dry carbonyl and oxygen will explode on vigorous shaking with mercury.6 Oxygen. Mixtures may explode.3 

Wear butyl rubber gloves, laboratory coat, goggles, and breathing apparatus. Absorb with a 1 1 1 mixture by weight of sodium carbonate or calcium carbonate, clay cat litter (bentonite), and sand. Scoop solid into an appropriately labeled container for disposal by burning.8 11 

72-2) in F344/N Rats and B6C3F1 Mice (Inhalation Studies). NTP-TRS No. 453, US Department of Health and Human Services, Public Health Service, 1996 

lARC Monographs on the Evaluation of Carcinogenic Risks to Flumans. Vol 49, Chromium, nickel and welding, pp 257 45. Lyon, International Agency for Research on Cancer, 1990 

Chashschin VP, Artunina GP, Norseth T Congenital defects, abortion and other health effects in nickel refinery workers. Sci Total Environ 148 287-91, 1994 

Purification intermediate in refining nickel catalyst in the petroleum, plastic, and rubber industries 

Toxicology. Nickel carbonyl is a severe pulmonary irritant. 

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AH the common monobasic (107) and dibasic esters (108) of tetrahydrofurfuryl alcohol have been prepared by conventional techniques the dibasic esters and some of the mono esters are effective as primary or secondary plasticizers for vinyl polymers. Tetrahydrofurfuryl acrylate [2399-48-6] and methacrjiate [2455-24-5] specialty monomers, have been produced by carbonylation (nickel carbonyl and acetylene) of the alcohol (109) as weU as by direct esterification (110—112) and ester interchange (111). 

Butynediol is more difficult to polymerize than propargyl alcohol, but it cyclotrimerizes to hexamethylolbenzene [2715-91 -5] (benzenehexamethanol) with a nickel carbonyl—phosphine catalyst (64) with a rhodium chloride—arsine catalyst a yield of 70% is claimed (65). 

With a nickel carbonyl catalyst, hydrochloric acid, and an alcohol the initially formed aHenic ester cyclizes on distillation (198). 

Acetylene-Based Routes. Walter Reppe, the father of modem acetylene chemistry, discovered the reaction of nickel carbonyl with acetylene and water or alcohols to give acryUc acid or esters (75,76). This discovery led to several processes which have been in commercial use. The original Reppe reaction requires a stoichiometric ratio of nickel carbonyl to acetylene. The Rohm and Haas modified or semicatalytic process provides 60—80% of the carbon monoxide from a separate carbon monoxide feed and the remainder from nickel carbonyl (77—78). The reactions for the synthesis of ethyl acrylate are... 

The stoichiometric and the catalytic reactions occur simultaneously, but the catalytic reaction predominates. The process is started with stoichiometric amounts, but afterward, carbon monoxide, acetylene, and excess alcohol give most of the acrylate ester by the catalytic reaction. The nickel chloride is recovered and recycled to the nickel carbonyl synthesis step. The main by-product is ethyl propionate, which is difficult to separate from ethyl acrylate. However, by proper control of the feeds and reaction conditions, it is possible to keep the ethyl propionate content below 1%. Even so, this is significantly higher than the propionate content of the esters from the propylene oxidation route. 

The reaction is initiated with nickel carbonyl. The feeds are adjusted to give the bulk of the carbonyl from carbon monoxide. The reaction takes place continuously in an agitated reactor with a Hquid recirculation loop. The reaction is mn at about atmospheric pressure and at about 40°C with an acetylene carbon monoxide mole ratio of 1.1 1 in the presence of 20% excess alcohol. The reactor effluent is washed with nickel chloride brine to remove excess alcohol and nickel salts and the brine—alcohol mixture is stripped to recover alcohol for recycle. The stripped brine is again used as extractant, but with a bleed stream returned to the nickel carbonyl conversion unit. The neutralized cmde monomer is purified by a series of continuous, low pressure distillations. 

Nickel carbonyl is volatile, has Htde odor, and is extremely toxic. Symptoms of dangerous exposure may not appear for several days. Effective medical treatment should be started immediately. The plant should be designed to ensure containment of nickel carbonyl and to prevent operator contact. 

Nickel Carbonyl The extremely toxic gas nickel carbonyl can be detected at 0.01 ppb by measuring its chemiluminescent reaction with ozone in the presence of carbon monoxide. The reaction produces excited nickel(II) oxide by a chain process which generates many photons from each pollutant molecule to permit high sensitivity (315). 

Miscellaneous. Electron beams can be used to decompose a gas such as silver chloride and simultaneously deposit silver metal. An older technique is the thermal decomposition of volatile and extremely toxic gases such as nickel carbonyl [13463-39-3] Ni(CO)4, to form dense deposits or dendritic coatings by modification of coating parameters. 

Novel palladium catalysts show marked improvements in both yields and selectivities, compared to nickel carbonyl catalysts utilized in eadier commercial carbonylation processes (83,84). The palladium catalysts are also expected to be less hazardous. 

Propionic acid is accessible through the Hquid-phase carbonylation of ethylene over a nickel carbonyl catalyst (104), or via ethylene and formic acid over an iridium catalyst (105). Condensation of propionic acid with formaldehyde over a supported cesium catalyst gives MAA directiy with conversions of 30—40% and selectivities of 80—90% (106,107). Catalyst lifetime can be extended by adding low levels (several ppm) of cesium to the feed stream (108). 

Ca.rbonylProcess. Cmde nickel also can be refined to very pure nickel by the carbonyl process. The cmde nickel and carbon monoxide (qv) react at ca 100°C to form nickel carbonyl [13463-39-3] Ni(CO)4, which upon further heating to ca 200—300°C, decomposes to nickel metal and carbon monoxide. The process is highly selective because, under the operating conditions of temperature and atmospheric pressure, carbonyls of other elements that are present, eg, iron and cobalt, are not readily formed. 

In the carbonyl process, the Hquid is purified, vaporized, and rapidly heated to ca 300°C which results in the decomposition of the vapor to carbon monoxide and a fine high purity nickel powder of particle sizes <10 fim. This product is useflil for powder metallurgical appHcations (see Metallurgy, powder). Nickel carbonyl can also be decomposed in the presence of nickel powder, upon which the nickel is deposited. This process yields nickel pellets, typically about 0.8 cm dia and of >99.9 wt% purity. 

Nickel [7440-02-0] Ni, recognized as an element as early as 1754 (1), was not isolated until 1820 (2). It was mined from arsenic sulfide mineral deposits (3) and first used in an alloy called German Silver (4). Soon after, nickel was used as an anode in solutions of nickel sulfate [7786-81 A] NiSO, and nickel chloride [7718-54-9] NiCl, to electroplate jewelry. Nickel carbonyl [13463-39-3] Ni(C02)4, was discovered in 1890 (see Carbonyls). This material, distilled as a hquid, decomposes into carbon monoxide and pure nickel powder, a method used in nickel refining (5) (see Nickel and nickel alloys). 

Nickel sulfate also is made by the reaction of black nickel oxide and hot dilute sulfuric acid, or of dilute sulfuric acid and nickel carbonate. The reaction of nickel oxide and sulfuric acid has been studied and a reaction induction temperature of 49°C deterrnined (39). High purity nickel sulfate is made from the reaction of nickel carbonyl, sulfur dioxide, and oxygen in the gas phase at 100°C (40). Another method for the continuous manufacture of nickel sulfate is the gas-phase reaction of nickel carbonyl and nitric acid, recovering the soHd product in sulfuric acid, and continuously removing the soHd nickel sulfate from the acid mixture (41). In this last method, nickel carbonyl and sulfuric acid are fed into a closed-loop reactor. Nickel sulfate and carbon monoxide are produced the CO is thus recycled to form nickel carbonyl. 

Ma.nufa.cture. Nickel carbonyl can be prepared by the direct combination of carbon monoxide and metallic nickel (77). The presence of sulfur, the surface area, and the surface activity of the nickel affect the formation of nickel carbonyl (78). The thermodynamics of formation and reaction are documented (79). Two commercial processes are used for large-scale production (80). An atmospheric method, whereby carbon monoxide is passed over nickel sulfide and freshly reduced nickel metal, is used in the United Kingdom to produce pure nickel carbonyl (81). The second method, used in Canada, involves high pressure CO in the formation of iron and nickel carbonyls the two are separated by distillation (81). Very high pressure CO is required for the formation of cobalt carbonyl and a method has been described where the mixed carbonyls are scmbbed with ammonia or an amine and the cobalt is extracted as the ammine carbonyl (82). A discontinued commercial process in the United States involved the reaction of carbon monoxide with nickel sulfate solution. 

Substituted Nickel Carbonyl Complexes. The reaction of trimethyl phosphite and nickel carbonyl yields the monosubstituted colorless oil, (CO)2NiP(OCH )2 [17099-58-0] the disubstituted colorless oil, (CO)2Ni[P(OCH )2]2 [16787-28-3] and the trisubstituted white crystalline soHd,... 

Other Complexes. Several other classes of organonickel complexes are known. AHyl bromide and nickel carbonyl react to give a member of the TT-aHyl system [12012-90-7], [7T-C3H3NiBr]2 (100). Tris(r -ethene)nickel [50696-82-7] reacts with acetylene and l,2-bis(diisopropylphosphino)ethane to... 

Tetramethylcyclobutadiene dichloride [76404-16-5] can be prepared by reaction of nickel carbonyl and 3,4-dichlorotetramethylcyclobutene (CBD) in polar solvents (103). The complex is black-violet, mp 185°C (dec). 

Concentrations of nickel carbonyl as low as 30 ppm in air for 30 min may be lethal for humans. Individuals exposed to these high concentrations show immediate symptoms of dizziness, headache, shortness of breath, and vomiting. These early symptoms generally disappear in fresh air, but delayed symptoms may develop 12—36 h later. These latter symptoms include shortness of breath, cyanosis, chest pain, chills, and fever. In severe exposure cases. 

Nickel carbonyl should be used in totally enclosed systems or under good local exhaust. Plants and laboratories where nickel carbonyl is used should make use of air-monitoring devices, alarms should be present in case of accidental leakage, and appropriate personal respiratory protective devices should be readily available for emergency uses. Monitoring of urinary nickel levels is useful to help determine the severity of exposure and identify appropriate treatment measures. Some large-scale users of nickel carbonyl maintain a supply of sodium diethyldithiocarbamate, or Antabuse, a therapeutic agent, on hand for use in case of overexposure. 

It is good practice to keep concentrations of airborne nickel in any chemical form as low as possible and certainly below the relevant standard. Local exhaust ventilation is the preferred method, particularly for powders, but personal respirator protection may be employed where necessary. In the United States, the Occupational Safety and Health Administration (OSHA) personal exposure limit (PEL) for all forms of nickel except nickel carbonyl is 1 mg/m. The ACGIH TLVs are respectively 1 mg/m for Ni metal, insoluble compounds, and fume and dust from nickel sulfide roasting, and 0.1 mg/m for soluble nickel compounds. The ACGIH is considering whether to lower the TLVs for all forms of nickel to 0.05 mg/m, based on nonmalignant respiratory effects in experimental animals. 

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