Carbon monoxide vapor pressure

A method of estimating carbon monoxide vapor pressures over aqueous copper-ammonium salt solutions, under conditions outside the range of experimental data, was proposed by van Krevelen and Baans (1950). These authors concluded that the basic chemical reaction involved in the absorption of carbon monoxide by aminoniacal solutions is expressed in equation 16-26. By considering equilibrium relationships in this reaction, they derived an equation relating the carbon monoxide partial pressure to the solution composition as follows ... 

In addition to the carbon monoxide vapor pressure, the vapor pressures of other solution components are of interest in assisting the calculation of possible losses and heat requirements. Copper-ammonium carbonate solutions have an appreciably higher vapor pressure than solutions of the formate or salts of stronger acids because of the relatively high decomposition pressure of ammonium carbonate. The total vapor pressures of a number of solutions have been measured by Zhavoronkov and Reshchikov (1933) and Zhavoronkov and Chagunava (1940). 

In the proposed vapor phase processes for organic acid synthesis, carbon monoxide is passed with the vaporized aliphatic alcohol over catalysts similar in nature to those employed in the pressure synthesis of higher alcohols from hydrogen-carbon monoxide mixtures. Pressures on the order of 200 atmospheres are employed. Temperatures of about 200° to 300° C. are preferred but it is necessary to use somewhat higher ones in order to obtain sufficient reaction. Mixtures of the oxides of zinc and chromium or copper, promoted with alkali or alkaline earth oxides, are suitable catalysts for the formation of carbon-carbon linkages.97 Catalysts composed of an alkali, chromium, and molybdenum have been claimed for the synthesis of mixtures of higher alcohols, aldehydes, acids, esters, etc., from carbon monoxide and vaporized aliphatic alcohols as methanol, ethanol, etc., at temperatures of about 420° C. and a pressure of 200 atmospheres.98... 

Decarburization of IHX alloys was examined under purposely designed impure helium atmospheres with a low carbon monoxide partial pressure (see Fig. 3.6) and various water vapor content. Fig. 3.9 shows cross-sections through AUoy 230 after exposure under decarburizing conditions at 950°C and 250 h. Under a very dry atmosphere, AUoy 230 shows no surface oxide. When the water vapor partial pressure is higher, fuUy porous surface oxide is formed. In aU cases, intergranular Cr-rich carbides have been totaUy dissolved and large W-rich primary carbides are partiaUy destabilized. 

Under high pressures and temperatures, iodine reacts with oxygen to form iodine pentoxide [12029-98-0] (44). The reaction of iodine with carbon monoxide under acidic conditions is catalyzed by palladium salts (45). Phosphorous vapor and iodine react to form phosphoms trHodide [13455-01 -17, PI (46). 

The vapor pressure of carbon monoxide has been compiled (11). Liquid-phase vapor pressure is represented by equation 1, where P is the pressure in MPa or atm and Tis the temperature in K (2). 

Because the solution is capable of absorbing one mole of carbon monoxide per mole of cuprous ion, it is desirable to maximize the copper content of the solution. The ammonia not only complexes with the cuprous ion to permit absorption but also increases the copper solubiUty and thereby permits an even greater carbon monoxide absorption capacity. The ammonia concentration is set by a balance between ammonia vapor pressure and solution acidity. Weak organic acids, eg, formic, acetic, and carbonic acid, are used because they are relatively noncorrosive and inexpensive. A typical formic acid... 

All the refractory metals of Group IV and Group V form volatile suboxides at high temperatures. Just as the stability of carbon monoxide increases with an increase in temperature, these oxides also become more stable at higher temperatures. The vapor pressures of these suboxides can be calculated from the relationship ... 

V metals, vanadium has the least tendency to deoxidize by carbon monoxide evolution. This means that, at a given temperature and a given value of Pco, the residual carbon and/or oxygen contents in vanadium will be compared more to niobium and tantalum. In other words, the removal of carbon and/or oxygen from vanadium will occur to a much lesser extent than in the cases of niobium or tantalum. The effect of carbon deoxidation can be quite complicated if there is a significant loss of the metal by vaporization. The requirement of a low vapor pressure is also better satisfied by niobium and tantalum than by vanadium. 

In the refining of the Group V metals (which are more accurately represented as metal-carbon-oxygen alloys), carbon deoxidation is not the only method by which oxygen is removed, because sacrificial deoxidation also occurs simultaneously. The relative extents to which each of these two deoxidation modes contributes to the overall removal of oxygen can be assessed by calculating the ratio of the vapor pressures of carbon monoxide and the metal monoxide over the M-C-0 alloy. The value of this ratio for vanadium at 2000 K is given by the expression... 

Substances with high vapor pressure evaporate rapidly. Those with low vapor pressure evaporate slowly. The impact of vapor pressure on the rate of evaporation makes vapor pressure a very important property in considering the tactical use and duration of effectiveness of chemical agents. A potential chemical agent is valuable for employment when it has a reasonable vapor pressure. One with exceptionally high vapor pressure is of limited use. It vaporizes and dissipates too quickly. Examples are arsine and carbon monoxide. On the other hand, mechanical or thermal means may effectively aerosolize and disseminate solid and liquid agents of very low vapor pressure. Vapor pressure and volatility are related. Translated into volatility, vapor pressure is most understandable and useful. 

Sodium hydrosulfite is produced through the Formate process where sodium formate solution, sodium hydroxide, and liquid sulfur dioxide reacted in the presence of a recycled stream of methanol solvent. Other products are sodium sulfite, sodium bicarbonate, and carbon monoxide. In the reactor, sodium hydrosulfite is precipitated to form a slurry of sodium hydrosulfite in the solution of methanol, methyl formate, and other coproducts. The mixture is sent to a pressurized filter system to recover sodium hydrosulfite crystals that are dried in a steam-heated rotary drier before being packaged. Heat supply in this process is highly monitored in order not to decompose sodium hydrosulfite to sulfite. Purging is periodically carried out on the recycle stream, particularly those involving methanol, to avoid excessive buildup of impurities. Also, vaporized methanol from the drying process and liquors from the filtration process are recycled to the solvent recovery system to improve the efficiency of the plant. 

At 5 1 8°C, acetaldehyde vapor decomposes into methane and carbon monoxide according to CH3CHO - CH4 + CO. In a particular experiment carried out in a constant-volume BR (Hinshelwood and Hutchison, 1926), the initial pressure of acetaldehyde was 48.4 kPa,... 

A sample containing the gases carbon dioxide, carbon monoxide, and water vapor was analyzed and found to contain 4.5 mol of carbon dioxide, 4.0 mol of carbon monoxide, and 1.5 mol of water vapor. The mixture had a total pressure of 1.2 atm. What was the partial pressure of the carbon monoxide ... 

A continuous-flow reactor with a fixed catalyst bed was employed at pressurized conditions. Gaseous dimethyl ether was supplied to the reactor at its vapor pressure with carbon monoxide while liquid reactants such as methyl acetate, methyl iodide, and water were fed with microfeeders. Methyl acetate used in this experiment was dehydrated by Molecular Sieve 5A before use. A part of the reaction mixture was sampled with a heated syringe and was analyzed by gas chromatography. 

---