Kinetics Of Carbon Dioxide Research Articles

Chemical kinetics of carbon dioxide with glycidyl methacrylate using immobilized tributylamine supported on poly(styrene-co-vinylbenzyl chloride) as a catalyst

A soluble copolymer-supported catalyst containing pendant tributylammonium chloride was synthesized by the radical copolymerization of p-chloromethylated styrene followed by the addition reaction of the resulting copolymer with tributylamine. The absorption rate of carbon dioxide was measured from the absorption experiment into glycidyl methacrylate (GMA) solutions containing the catalyst in a semi-batch stirred tank with a plane gas–liquid interface at 0.1013 MPa. The reaction rate constants of the reaction between carbon dioxide and GMA were obtained by the analysis of the mass transfer mechanism accompanied by chemical reactions based on the film theory.Solvents such as toluene, N-methyl-2-pirrolidinone, and dimethyl sulfoxide influenced the reaction rate constants. Furthermore, this catalyst was compared to the monomeric tetrabutyl-ammonium chloride under the same reaction conditions.

Reaction Kinetics of Carbon Dioxide with Diethanolamine in Polar Organic Solvents

The chemical absorption rate of carbon dioxide with diethanoamine was measured in such nonaqueous solvents as methanol, ethanol, n‐propanol, n‐butanol, ethylene glycol, propylene glycol, and propylene carbonate, and in water at 298 K and 101.3 kPa using a semibatch stirred tank with a plane gas‐liquid interface. The overall reaction rate constant obtained under the condition of fast reaction regime from the measured rate of absorption was used to get the elementary reaction rate constants in complicated reactions represented by reaction mechanism of carbamate formation and the order of overall reaction of CO2 with amine. Correlation between the elementary reaction rate constant and the solubility parameter of the solvent was presented.

Adsorption of gases and vapors on nanoporous Ni2(4,4'-Bipyridine)3(NO3)4 metal-organic framework materials templated with methanol and ethanol: structural effects in adsorption kinetics.

Desolvation of Ni(2)(4,4'-bipyridine)(3)(NO(3))(4).2CH(3)OH and Ni(2)(4,4'-bipyridine)(3)(NO(3))(4).2C(2)H(5)OH give flexible metal-organic porous structures M and E, respectively, which have the same stoichiometry, but subtly different structures. This study combines measurements of the thermodynamics and kinetics of carbon dioxide, methanol, and ethanol sorption on adsorbents M and E over a range of temperatures with adsorbent structural characterization at different adsorbate (guest) loadings. The adsorption kinetics for methanol and ethanol adsorption on porous structure E obey a linear driving force (LDF) mass transfer model for adsorption at low surface coverage. The corresponding adsorption kinetics for porous structure M follow a double exponential (DE) model, which is consistent with two different barriers for diffusion through the windows and along the pores in the structure. The former is a high-energy barrier due to the opening of the windows in the structure, required to allow adsorption to occur, while the latter is a lower-energy barrier for diffusion in the pore cavities. X-ray diffraction studies at various methanol and ethanol loadings showed that the host porous structures E and M underwent different scissoring motions, leading to an increase in unit cell volume with the space group remaining unchanged during adsorption. The results are discussed in terms of reversible adsorbate/adsorbent (host/guest) structural changes and the adsorption mechanism involving hydrogen-bonding interactions with specific surface sites for methanol and ethanol adsorption in relation to pore size and extent of filling. This paper contains the first evidence for individual kinetic barriers to diffusion through windows and pore cavities in flexible porous coordination polymer frameworks.

Effect of Piperazine on the Kinetics of Carbon Dioxide with Aqueous Solutions of 2-Amino-2-methyl-1-propanol

The absorption of CO2 into aqueous mixtures of 2-amino-2-methyl-1-propanol (AMP) and piperazine was investigated. A wetted-sphere absorption apparatus was used to measure the absorption rate. The absorption rates of CO2 into aqueous solutions of AMP in the range of 0.55−3.35 kmol/m3 were measured. The experimental temperatures were 303 and 313 K. The zwitterion deprotonation mechanism was used to interpret the kinetic data of aqueous solutions of AMP. The absorption rates of aqueous mixtures of AMP and piperazine were measured. Piperazine concentrations of 0.058, 0.115, and 0.233 kmol/m3 were added for each AMP solution. The apparent reaction rate constants increased with the addition of piperazine. The effect of piperazine on the reaction rate of CO2 with aqueous solutions of AMP consists of the contribution for the zwitterion deprotonation and the direct reaction of piperazine with CO2. The zwitterion deprotonation constants of all bases presented in liquid and the direct reaction rate constant of piperazine were obtained.

Adsorption dynamics measured by permeation and batch adsorption methods

We have measured the adsorption equilibrium and kinetics of carbon dioxide on a commercially available activated carbon by two methods; permeation and batch adsorption. The two methods are compared and found to yield consistent results. All experiments are performed at low pressure (<5 torr) and in this range the isotherm was found to be reversible and non-linear. Because of the observed non-linearity, the batch adsorption experiments were conducted differentially in order to obtain the adsorbed phase diffusivity at local conditions. The diffusion process was described by gas phase diffusion, adsorption and adsorbed phase diffusion which was modelled using the Darken relation. Results of adsorption equilibria and kinetics will be discussed in detail in this investigation.

CARBON DIOXIDE KINETICS DURING ANESTHESIA: Pathophysiology and Monitoring

During clinical anesthesia, the study of CO 2 kinetics is restricted mostly to evaluation of capnography. Capnography, the measurement and graphic display of airway opening CO 2 concentration versus time, is used to confirm correct placement of the tracheal tube and to estimate the adequacy of pulmonary ventilation. However, the study of CO 2 kinetics can offer a rich array of respiratory, cardiovascular, and metabolic information, 6 , 7 , 9 both during traditional steady-state analysis and during the relatively newer study of non–steady-state conditions. In this article, I review the role of capnography in the study of traditional steady-state CO 2 kinetics. We explore exciting new methodology that can monitor CO 2 storage and transport in the body. Then we use these monitoring tools to examine clinically relevant examples of CO 2 kinetics pathophysiology during non–steady states that occur relatively commonly during anesthesia. Accordingly, this review of CO 2 kinetics during anesthesia incorporates the following scheme: • CO 2 kinetics: generation of the normal capnogram; main-stream versus side-stream sampling capnometry • Capnogram: monitoring of airway patency and pulmonary ventilation • Capnogram: mechanical and pathophysiologic effects • Steady-state CO 2 kinetics: effects on alveolar P co 2 , with special emphasis on the effect of alveolar dead space • New methodology to examine CO 2 kinetics during non–steady state: CO 2 expirogram (plot of exhaled P co 2 versus tidal volume), average alveolar expired P co 2 versus end-tidal P co 2 , CO 2 volume exhaled per breath • Non–steady-state conditions: effects on CO 2 kinetics; pathophysiology includes abrupt decrease in cardiac output, application of positive end-expiratory pressure, and pulmonary embolism • Future directions: gas exchange and metabolic monitoring in the next century Table 1 provides a legend and summary of abbreviations.

Kinetics of carbon dioxide and methyldiethanolamine with phosphoric acid

AbstractThe Kinetics of the reaction between carbon dioxide and methyldiethanolamine (MDEA) were studied in the presence of various amounts of phosphoric acid at 298 K, 308 K, and 318 K. A stirred cell with a known interfacial area was used at atmospheric pressure to measure the volumetric absorption rate of CO2 flowing through the vessel.The addition of phosphoric acid to an aqueous solution of MDEA resulted in a Bronsted acid‐base neutralization reaction. While virtually all of the acid was consumed by the neutralization reaction, a large part of the MEDA remained in its free form. The absorption of carbon dioxide in these solutions was slower than expected, given the amount of free MDEA present. The rate depression in the presence of hydrogen phosphate anions was attributed to the stabilization of the reaction transition state between MDEA, water, and carbon dioxide through charge dispersal.

Kinetics of Carbon Dioxide with tertiary Amines in aqueous solution

AbstractThe reaction of CO2 with TEA, DMMEA, and DEMEA has been studied at 293, 303, 318 and 333 K. All the kinetic experiments were carried out in a stirred cell reactor operated with a flat, smooth and horizontal gas‐liquid interface. A numerical method, which describes mass transfer accompanied by reversible chemical reactions, has been applied to infer rate constants from the experimental data. It is argued that the contribution of the CO2 reaction with OH− to the observed reaction rate may have been overstimated in most literature on tertiary amine kinetics as serious depletion of OH− toward the gas‐liquid interface usually occurs.For all the amines studied, the reaction order in amine was found to be about one for each temperature investigated. This is in good agreement with the base catalysis mechanism proposed by Donaldson and Nguyen (1980). All kinetic data could be summarized reasonably well in one Brønsted relationship.

Kinetics of carbon dioxide during cardiopulmonary resuscitation.

CO2 kinetics during CPR was investigated in 15 anesthetized piglets. BP, blood gases, and acid-base balance were monitored through catheters in the carotid artery and a central vein, as well as in cerebrospinal fluid. Cardiac arrest was induced by a transthoracic direct current shock. CPR was begun immediately by artificial ventilation and simultaneous external chest compressions. Epinephrine was administered after 8 min of CPR. One group (n = 5) of animals received no buffer treatment while another (n = 5) received an infusion of 75 mmol sodium bicarbonate and a third group (n = 5) received an equivalent amount of tris-buffer mixture. The results of these experiments, as well as previously described circulatory variables during CPR, were analyzed using a computer model describing the CO2 kinetics of the pig. Our main finding was that PaCO2 was positively correlated to cardiac output during CPR; improved cardiac output during CPR resulted in more efficient tissue CO2 elimination and was associated with increased survival rates. PaCO2 was also somewhat reduced by efficient alveolar hyperventilation. The arterial PCO2 and pH did not reflect the acid-base balance in peripheral tissues. During CPR, bicarbonate and tris-buffer mixture both quickly passed through the blood-brain barrier. When buffer treatment is indicated during CPR, a buffer which does not increase tissue PCO2 may be the drug of choice.

Kinetics of carbon dioxide dissociation behind a shock front

The solution of a number of problems concerning the flow over or through bodies of a hot gas containing free or bound carbon and oxygen atoms requires a knowledge of the kinetics of the physicochemical processes in the oxides of carbon. This paper is devoted to an examination of the dissociation kinetics of carbon dioxide at high temperatures (up to 6000° K).

The Kinetics of Carbon Dioxide and Carbon Formation from Carbon Monoxide1a

The Kinetics of Carbon Dioxide and Carbon Formation from Carbon Monoxide^1a