Pressure, carbon dioxide

Fig. 7. Glass-tiansition tempeiatuies of (A) polymetfiylinetfiaciylate (PMMA) ( ) polymetfiylinetfiaciylate-fo-styiene (SMMA60) and ( ) polystyrene (PS) as a function of carbon dioxide pressure, where the solid line represents CO2 vapor pressure (37). To convert MPa to psi, multiply by 145.

Beryllium Carbonates. BeryUium carbonate tetrahydrate [60883-64-9] BeCO 4H2O, has been prepared by passing carbon dioxide through an aqueous suspension of beryUium hydroxide. It is unstable and is obtained only when the solution is under carbon dioxide pressure. BeryUium oxide carbonate [66104-25-4] is precipitated when sodium carbonate is added to a beryUium salt solution. Carbon dioxide is evolved. The precipitate appears to be a mixture of beryUium hydroxide and the normal carbonate, BeCO, and usuaUy contains two to five molecules of Be(OH)2 for each BeCO. ... 

Carbon dioxide gas is added to either the water used to prepare beverages or the symp and water mixture, depending on the type of manufactuting equipment. In both manufactuting processes, the carbon dioxide gas is iatroduced under pressure to the system. The carbonation of the beverage is dependent on the carbon dioxide pressure and the temperature of the mixture. 

The synthesis of DMC from EC and methanol was carried out in a batch reactor using various quaternary ammonium salt catalysts under carbon dioxide pressure. 

Provided that the temperature and the carbon dioxide pressure conditions in the calcination furnace are such that they correspond to the point A, or to any point above the calcium carbonate line, no dissociation occurs because in such a situation,... 

The hazard of well blowout is greatest if hydrochloric acid wastes exceeding certain temperature and concentration limits are injected into a carbonate formation. When carbonate dissolves in acid, carbon dioxide is formed. Normally, this gas remains dissolved in the formation waters at deep-well temperatures and pressures, but if the temperature exceeds 88°F or acid concentration exceeds 6% HC1, carbon dioxide will separate from the formation waters as a gas. The resulting gas accumulation can increase pressures to a point where, if injection stops or drops below the subsurface carbon dioxide pressure, a blowout can occur. 

Keurentjes et al. performed a continuous hydrogenation of 1-butene in supercritical carbon dioxide.[9,10] A fluorous derivative of Wilkinson s catalyst was prepared in situ by mixing the ligand with [(COD)RhCl]2 under hydrogen / carbon dioxide pressure (Figure 4.37). 

Figure 9.1. Carbon dioxide pressure-temperature phase diagram adapted from McHugh and Krukonis (1994).

The key feature of the systems to be considered in this book is that they have short memories that is, the effects of perturbations diminish with the passage of time. In the example of this chapter, the carbon dioxide pressure returns to a value of 1 within a century or two of the perturbation, regardless of the size of the initial perturbation. In this kind of system, computational errors do not grow as the calculation proceeds instead, the system forgets old errors. That is why the reverse Euler method is useful despite its simplicity and limited accuracy. The many properties of the environment that are reasonably stable and predictable can, in principle, be described by equations with just this kind of stability, and these are the properties that can be simulated using the computational methods described in this book. 

As soon as micro-bubbles only are being produced in the nitrometer close the stop-cock on the connecting tube, detach the rubber connecting tube from the combustion tube, close the latter with a cap made from rubber tubing, and leave to cool whilst maintaining the internal carbon dioxide pressure. Remove the nitrometer to a somewhat cooler room (room in which the barometer is kept preferably) after raising the bulb so that the surfaces of the two columns of liquid are at the same level. 

Malinin, S.D. Savelyeva, N.I. "Solubility of Carbon Dioxide in Sodium Chloride and Calcium Chloride Solutions at Temperatures of 25, 50, and 75 C and Elevated Carbon Dioxide Pressures," Geochem. Intern., 1972, 9, (3), 410-18. 

If heparin comprises 10% or more of the total volume of a sample for blood gas analysis, errors in measurements of carbon dioxide pressure, bicarbonate concentration, and base excess may occur. 

Fig. 12.—Influence of carbon dioxide pressure on the rate of the reaction C02+H2- C0+H20 at 1,000°C. Pressure of hydrogen 100 mm.

To a good first approximation, the Great Lakes fit a model involving the equilibrium of calcite, dolomite, apatite, kao-Unite, gibbsite, Na- and K-feldspars at 5°C., 1 atm. total pressure with air of PCo2 = 3.5 X 10" atm. and water. Dynamic models, considering carbon dioxide pressure and temperature as variables (but gross concentrations fixed), show that cold waters contain excess carbon dioxide and are unsaturated with respect to calcite, dolomite, and apatite, whereas warm waters are nearly at equilibrium with the atmosphere but somewhat supersaturated with respect to calcite, dolomite, and apatite. 

Figures 5 and 6 show the results of the calculations, and they are compared with the actual data distribution as shown by a dashed bounding line. With both calcite and dolomite, colder waters match conditions of carbon dioxide pressure greater than atmospheric, and high temperature conditions match carbon dioxide pressure nearly the same as the atmosphere. It appears the degree of mixing and the rate of carbon dioxide diffusion is of prime importance when considering approach to liquid, gas, and solid equilibrium.

The carbon dioxide pressure is only 3.6 bar. From the carbonation chart, assuming a temperature of 20 °C, the volumes carbonation at 4 bar would be 4.3 but only 4.1 at 3.6 bar. Hence, with the presence of ah we have lost 0.2 volumes carbonation. This is the maximum tolerance normally given for volumes carbonation during the manufacture of soft drinks. 

In order to remove the undesirable Texanol, ve extracted the pigment with supercritical carbon dioxide which was held at a low pressure (100 atm) for five minutes. The extract was found to contain Texanol. We increased the carbon dioxide pressure to 400 atm for five minutes to extract the pigment additive. The pressure control in SFE allows us to control the solubilizing power of the carbon dioxide, therefore, perform selective extractions. 

To dissolve a greater quantity of carbon dioxide, pressure is applied while dissolving carbon dioxide in water. The soda bottles are then sealed tightly so that no gas escapes. When the seal is broken or the cap is removed, the pressure is released and carbon dioxide gas is released with a sound. 

Figure H. Carbon dioxide pressures required for sulfur compound absorption.

Carbon dioxide removal by slurry absorption is attractive down to about -75°C, a temperature easily achieved by slurry regeneration to slightly above one atmosphere carbon dioxide pressure. For example, with a -75°C exit gas temperature, slurry absorption reduces the carbon dioxide content of a 1000 psia synthesis gas from about 13 to about 4 mole percent, a 70% reduction in carbon dioxide content. The exact level to which carbon dioxide can be removed from a treated gas by slurry absorption also depends on the solubility of solid carbon dioxide in the treated gas the solubility of solid carbon dioxide in synthesis gas (3H2 CO) is illustrated in Figure 10 for several synthesis gas pressures. Fine removal of carbon dioxide to lower levels is accomplished by conventional absorption into a slip stream of the slurry solvent which is regenerated to meet particular product gas carbon dioxide specifications. 

Procedures are reported for the synthesis of ethyleneurea from ethylene glycol or ethanolamine either with urea or with ammonia and carbon dioxide. Pressure and other variables affecting the reactions are discussed and a mechanism is suggested by which amination of the carbon skeleton takes place. 

A supercritical extraction procedure was developed to determine naled, methyleugenol, and cuelure in soil samples [28]. Recovery of methyleugenol was reported as 91-101% after spiking the sample with standard at concentrations of 0.25-45 pg/g. The supercritical fluid was carbon dioxide (pressure of 27.6 Mpa), and the method worked for 5-30% soil moisture. 

Figure 9. Breakthrough volume as a function of carbon dioxide pressure for benzene on the crosslinked polymeric resin.

Figure 10. Retention volume for benzene versus carbon dioxide pressure on the styrene/divinylbenzene resin.

ELECTROLYTIC PRODUCTION OF CARBON NANO-TUBES IN CHLORIDE-OXIDE MELTS UNDER CARBON DIOXIDE PRESSURE... 

Novoselova I.A., Volkov S.V., Oliinyk N.F., Shapoval V.I. (2003) High -temperature Electrochemical Synthesis of Carboncontaining Inorganic Compounds under Excessive Carbon Dioxide Pressure. J. Mining Metallurgy. 39 (1-2) B, 281-293. 

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