Cobalt laboratory preparation

Catalysts. The catalysts used were commercial cobalt molybdate and a laboratory-prepared depleted uranium catalyst. The cobalt molybdate consisted of cobalt and molybdenum oxides on 6- to 8-mesh alumina granules. The uranium catalyst consisted of 7.7% depleted uranium (uranium from which the U-235 has been removed) in the oxide form on 1/8-in. H-151 alumina balls. This catalyst had produced high gas yields in previous hydrogenation experiments with shale oil, and these results suggested its possible use as a hydrogasification catalyst. Both catalysts were maintained under a hydrogen atmosphere at approximate reaction temperature and pressure for about 12 hours before each experiment. 

Many optically-active organic molecules are present in plants and animals, and they can often be isolated and obtained in a pure form. In recent years, considerable success has been achieved in the selective synthesis of individual isomers. However, laboratory preparations of compounds that can exhibit optical activity normally yield 50-50 (racemic) mixtures of the two optical isomers and hence produce an optically-inactive material (Section 3.4). Therefore, the basic step in the laboratory preparation of an optically-active coordination compound is separation from its optical isomer. For example, racemic [Co(en)3] is readily prepared by the air oxidation of a cobalt(II) salt... 

Manufacture. Furan is produced commercially by decarbonylation of furfural in the presence of a noble metal catalyst (97—100). Nickel or cobalt catalysts have also been reported (101—103) as weU as noncatalytic pyrolysis at high temperature. Furan can also be prepared by decarboxylation of 2-furoic acid this method is usually considered a laboratory procedure. 

There are currentiy no commercial producers of C-19 dicarboxyhc acids. During the 1970s BASF and Union Camp Corporation offered developmental products, but they were never commercialized (78). The Northern Regional Research Laboratory (NRRL) carried out extensive studies on preparing C-19 dicarboxyhc acids via hydroformylation using both cobalt catalyst and rhodium complexes as catalysts (78). In addition, the NRRL developed a simplified method to prepare 9-(10)-carboxystearic acid in high yields using a palladium catalyst (79). 

Catalysts - A commercial Raney nickel (RNi-C) and a laboratory Raney nickel (RNi-L) were used in this study. RNi-C was supplied in an aqueous suspension (pH < 10.5, A1 < 7 wt %, particle size 0.012-0.128 mm). Prior to the activity test, RNi-C catalyst (2 g wet, 1.4 g dry, aqueous suspension) was washed three times with ethanol (20 ml) and twice with cyclohexane (CH) (20 mL) in order to remove water from the catalyst. RCN was then exchanged for the cyclohexane and the catalyst sample was introduced into the reactor as a suspension in the substrate. RNi-L catalyst was prepared from a 50 % Ni-50 % A1 alloy (0.045-0.1 mm in size) by treatment with NaOH which dissolved most of the Al. This catalyst was stored in passivated and dried form. Prior to the activity test, the catalyst (0.3 g) was treated in H2 at 250 °C for 2 h and then introduced to the reactor under CH. Raney cobalt (RCo), a commercial product, was treated likewise. Alumina supported Ru, Rh, Pd and Pt catalysts (powder) containing 5 wt. % of metal were purchased from Engelhard in reduced form. Prior to the activity test, catalyst (1.5 g) was treated in H2 at 250 °C for 2 h and then introduced to the reactor under solvent. 10 % Ni and 10 % Co/y-Al203 (200 m2/g) catalysts were prepared by incipient wetness impregnation using nitrate precursors. After drying the samples were calcined and reduced at 500 °C for 2 h and were then introduced to the reactor under CH. 

R. H. Herber Dr. Sano really has done most of the work on barium stannate in our laboratory. This material has one weakness when compared with the standard in cobalt-57 spectroscopy—i,e, it has no quadru-pole splitting. Otherwise, it is a stoichiometric compound which one can presumably prepare easily and reproducibly. I am not the person to propose it as a standard. Moreover, there are some other suitable candidates we haven t as yet studied, which should be considered. 

The hydroformylation of alkenes generally has been considered to be an industrial reaction unavailable to a laboratory scale process. Usually bench chemists are neither willing nor able to carry out such a reaction, particularly at the high pressures (200 bar) necessary for the hydrocarbonylation reactions utilizing a cobalt catalyst. (Most of the previous literature reports pressures in atmospheres or pounds per square inch. All pressures in this chapter are reported in bars (SI) the relationship is 14.696 p.s.i. = 1 atm = 101 325 Pa = 1.013 25 bar.) However, hydroformylation reactions with rhodium require much lower pressures and related carbonylation reactions can be carried out at 1-10 bar. Furthermore, pressure equipment is available from a variety of suppliers and costs less than a routine IR instrument. Provided a suitable pressure room is available, even the high pressure reactions can be carried out safely and easily. The hydroformylation of cyclohexene to cyclohexanecarbaldehyde using a rhodium catalyst is an Organic Syntheses preparation (see Section 4.5.2.5). 

The compounds [Fe(NO)2I]2, [Co(NO)2I]x, and [Ni(NO)I]x have been prepared before with gas-solid reactions at elevated temperatures.1 However, the syntheses were complicated and the yields were relatively low, expecially for the cobalt and nickel compounds. In addition, the syntheses of these compounds required equipment not available in every laboratory. The syntheses described herein require only readily available glassware and chemicals. If desired, these compounds can be prepared in macro quantities by the methods described below. 

T n 1962 the U. S. Army opened at its Natick Laboratories in Natick, Mass., the world s largest irradiation laboratory (2) for preserving foods by ionizing energy (Figure 1). This laboratory is unique in that, in addition to having two radiation sources, a 24-m.e.v., 18-kw. electron linear accelerator and a 1,250,000-curie cobalt-60 isotope source, it includes a food development-preparation laboratory and an experimental development kitchen (Figure 2). 

Alloys are prepared commercially and in the laboratory by melting the active metal and aluminum in a crucible and quenching the resultant melt which is then crushed and screened to the particle size range required for a particular application. The alloy composition is very important as different phases leach quite differently leading to markedly different porosities and crystallite sizes of the active metal. Mondolfo [14] provides an excellent compilation of the binary and ternary phase diagrams for aluminum alloys including those used for the preparation of skeletal metal catalysts. Alloys of a number of compositions are available commercially for activation in the laboratory or plant. They include alloys of aluminum with nickel, copper, cobalt, chromium-nickel, molybdenum-nickel, cobalt-nickel, and iron-nickel. 

In the first part of this article, focusing attention on polymer-supported cobalt phosphine complex 1 and arene ruthenium complex 2, we review contributions from our laboratory that show how organometallics can be efficiently attached to derivitised polystyrene and we outline their synthetic versatility.2,3 Following this, we discuss the preparation of a supported ruthenium complex, 3, and its use in oxidation and transfer hydrogenation catalysis. 

The preparations described here are developed from published work by Malatesta et al.5 and from more recent studies in the contributors own laboratory.2 The cobalt and nickel complexes are prepared by reduction of the corresponding metal nitrates with sodium tetrahydroborate in the presence of excess ligand, whereas the syntheses of the rhodium and platinum complexes involve simple ligand exchange processes. The preparative routes are suitable for use with triphenyl- or p-substituted triphenyl phosphites reactions involving o- or m-substituted triphenyl phosphites give much reduced yields of products which are difficult to crystallize and are very air-sensitive. These features probably reflect the unfavorable stereochemistry of the o- and m-substituted ligands. 

Approximately 2 million tons of acetic acid are produced each year in the United States for a variety of purposes, including preparation of the vinyl acetate polymer u.sed in paints and adhesives. The industrial method of acetic acid synthesis involves a cobalt acetate-catalyzed air oxidation of acetaldehyde, but this method is not used in the laboratory. 

The Nicholas reaction was used to synthesize the p-lactam precursor of thienamycin in the laboratory of P.A. Jacobi and thereby accomplish its formal total synthesis. The necessary p-amino acid was prepared by the condensation of a boron enolate (derived from an acylated oxazolidinone) with the cobalt complex of an enantiopure propargylic ether. The resulting adduct was oxidized with ceric ammonium nitrate (CAN) to remove the cobalt protecting group from the triple bond, and the product was obtained with a 17 1 anti.syn selectivity and in good yield. 

The total synthesis of the sesquiterpene (+)-taylorione was achieved in the laboratory of J.G. Donkervoort who used the modified Pauson-Khand reaction to prepare the five-membered ring of the natural product. The preformed alkyne-cobalt complex was exposed to excess triethylamine-A/-oxide, which oxidized off two CO ligands to free up a coordination site for the ethylene. The optimum pressure of the ethylene gas had to be at 25 atm, and the reaction was conducted in an autoclave. 

The key bicyclo[4.3.0]nonenone intermediate in the total synthesis of ( )-13-deoxyserratine was prepared by a highly diastereoselective intramoiecuiar Pauson-Khand reaction of a functionalized enyne-cobalt complex in the laboratory... 

Although rare, manufacturing errors can cause production of products that contain toxic metals. In the early 1960s, a Canadian beer brewery accidentally contaminated a large lot of its product with cobalt The product was sold to and consumed by the public, resulting in an outbreak of renal disease and cardiomyopathy. In this type of situation, the U.S. Public Health Service is often called in to identify the cause of an outbreak of unusual symptoms. The clinical laboratory should be prepared to support these types of investigations. 

Recently, several laboratories have reported stereochemical analysis using NMR spectroscopy of series of MMA oligomers (from unimer to pentamer) prepared by radical polymerization with tetraphenylethane initiators,266 by radical telomerization with thiophenol,267 and by group transfer polymerization.268 These polymerization systems are not stereospecific (rather syndio-tactic) and thus the resultant MMA oligomers consist of comparable amounts of some stereoisomers. Cacioli and co-workers267 prepared MMA oligomers by radical telomerization with cobalt (II) tetraphenyl porphyrin, and studied them using two-dimensional NMR. They isolated three of four possible stereoisomers of the pentamer ( = 3) ... 

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