Carbon monoxide manufacturing methods

The mildly endothermic steam reforming of methanol is one of the reasons why methanol is finding favour with vehicle manufacturers as a possible fuel for FCVs. Little heat needs to be supplied to sustain the reaction, which will readily occur at modest temperatures (e.g. 250°C) over catalysts of mild activity such as copper supported on zinc oxide. Notice also that carbon monoxide does not feature as a principal product of methanol reforming. This makes the methanol reformate particularly suited to PEM fuel cells, where carbon monoxide, even at the ppm level, can cause substantial losses in performance because of poisoning of the platinum anode electrochemical catalyst. However, it is important to note that although carbon monoxide does not feature in reaction 8.7, this does not mean that it is not produced at all. The water-gas shift reaction of reaction 8.5 is reversible, and carbon monoxide in small quantities is produced. The result is that the carbon monoxide removal methods described in Section 8.4.9 are still needed with PEM fuel cells, though the CO levels are low enough for PAFC. 

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. 

The third and now preferred method of acetic acid manufacture is the carbonylation of methanol (Monsanto process), involving reaction of methanol and carbon monoxide (both derived from methane). This is discussed in Chapter 12, Section 3. 

The recent dramatic increase in the price of petroleum feedstocks has made the search for high selectivities more urgent. Several new processes based on carbon monoxide sources are currently competing with older oxidation processes.103,104 The more straightforward synthesis of acetic acid from methanol carbonylation (Monsanto process) has made the Wacker process obsolete for the manufacture of acetaldehyde, which used to be one of the main acetic acid precursors. Several new methods for the synthesis of ethylene glycol have also recently emerged and will compete with the epoxidation of ethylene, which is not sufficiently selective. The direct synthesis of ethylene... 

In 1910 Haber 7 found that in presence of metallic osmium 1 volume of nitrogen unites with 3 volumes of hydrogen at 550° C. and 200 atmospheres, the yield being 8 per cent, of the mixed gases. On the manufacturing scale, osmium can be replaced by the less costly uranium, and a continuous circulation method is employed, with a temperature about 500° C.8 Any carbon monoxide present in the hydrogen should be removed.9... 

The commercial method of making formic acid is by the second reaction. It is of especial importance in the manufacture of oxalic acid and will therefore be discussed in detail in connection with that acid (p. 269). In the laboratory it is generally made by heating oxalic acid in glycerol. The oxalic acid breaks down and yields formic acid as will be shown under oxalic acid. When heated with sulphuric acid formic acid breaks down and yields water and carbon monoxide, which is the reverse of the second reaction just given. 

The earliest methods for the manufacture of phosgene were based upon John Davy s original procedure of exposing a mixture of carbon monoxide and dichlorine to sunlight [577]. Later methods (used to a limited extent in Italy and France during World War I) involved the oxidation of tetrachloromethane or hexachloroethane with suIfur(VI) oxide or fuming sulfuric acid (see Chapter 5) [577,1778]. Alternative methods proposed for the manufacture of phosgene, but which have not been commercialized, are described in Chapter 5. 

The manufacture of any large-scale, industrially important compound is susceptible to changes in the availability of raw materials, the economic climate, legislative constraints, and the particular manufacturer s local considerations. There is little doubt, at the present time, that (under the vast majority of conditions) the synthesis of phosgene from carbon monoxide and dichlorine, catalysed by activated charcoal, constitutes the most favourable method in economic terms. 

The physical structure, which can be changed by suitable methods of catalyst manufacturing, is. of decisive importance (promoters high-melting oxides supports kieselguhr of cobalt and nickel catalysts pretreatment low-temperature reduction which limits the size of the crystals, or carbon monoxide treatment of iron catalysts which increases the surface by breaking up the structure with carbon). 

If required, relatively pure carbon monoxide can be recovered by cryogenic separation (i.e. condensation at very low temperatures), use of selective scrubbing solutions (for example CUAICI4 in toluene, the COSORB process) or solid adsorbents, and by other methods. Some CO recovery techniques are also applicable to the CO-rich (c. 70% molar) off-gases from basic oxygen furnaces and the leaner off-gases from air blast furnaces produced in steel manufacture, though operations of this type are still limited. 

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