Carbon monoxide poisoning reaction

This reaction serves for removal of carbon monoxide from gas mixtures and is usually carried out over supported metal catalysts. In reforming techniques, carbon monoxide, poisonous for the catalyst in fuel cells, is removed in such a way. It is also applied in automobiles for reducing the exhaust gas carbon monoxide to an environmentally acceptable level. 

The ideal performance of a fuel cell depends on the electrochemical reactions that occur with different fuels and oxygen as summarized in Table 2-1. Low-temperature fuel cells (PEFC, AFC, and PAFC) require noble metal electrocatalysts to achieve practical reaction rates at the anode and cathode, and H2 is the only acceptable fuel. With high-temperature fuel cells (MCFC, ITSOFC, and SOFC), the requirements for catalysis are relaxed, and the number of potential fuels expands. Carbon monoxide "poisons" a noble metal anode catalyst such as platinum (Pt) in low-temperature... 

Caution. Carbon monoxide (poisonous) is evolved during this reaction, which must be carried out in a well-ventilated hood. 

Air pollution is one of the worst problems caused by industries, agriculture, power stations, aerosols and other chemicals, and coal and other fires. As a result we suffer from headaches, respiratory tract infections and ailments, asthma, bronchitis, emphysema, eye problems, and eventually a profound breakdown in health manifested by various cancers. Other environmental hazards include lead from gasoline — which causes hyperactivity and birth defects — acid rain, carbon monoxide poisoning, water pollution, and radiation. Clinical ecologists treat illnesses and disorders that they believe stem from an individual s reaction to these environmental factors. They practice what is known as environmental medicine, and they estimate that between 10 and 30% of the population suffers from some form of ecological disease (Thomas, 1997 and General References). 

As shown in Figure 5.4 and Figure 5.17 and as described for each of the major processes that produce synthesis gas, the Water Gas Shift Conversion or the Carbon Monoxide Shift reaction is one of the traditional purification steps that will still be found in many ammonia plants. The CO must be removed because it acts as a poison to the catalyst that is used in ammonia synthesis. 

According to Eidus (90) carbides formed on cobalt or nickel catalysts are neither intermediate products nor catalysts promoting the formation of hydrocarbons from carbon monoxide and hydrogen. In the absence of hydrogen carbon monoxide poisoned the cobalt catalyst. Despite Eidus results, Braude and Bruns (42) supported Craxford s assumption that the carbide is formed by reaction of the metal (iron) with carbon monoxide and hydrogen. It was pointed out by Eidus (84a) that Braude and Bruns did not clearly distinguish between the carbide and free carbon... 

Of these reactions in which CO coordinates with the oxidized form of metals, the most important is the reaction with the iron atom in the hemoglobin of the blood, leading to carbon monoxide poisoning. This iron atom is part of a ring structure similar to that in chlorophyll (Chap. 6), and it ordinarily takes part in the metabolic process by reversibly forming a Fe—0—0— compound with the oxygen of the air. If carbon monoxide... 

Figure 3.1 The composition of reaction mixture as a function of reaction time in the hydrogenation of 1,5-cyclooctadiene over unpoisoned (a), phenylacetaldehyde-poisoned (b), and carbon monoxide-poisoned (c) palladium catalysts. The points are experimental values, and the curves show the simulations using the values given in Table 3.4. For the reaction conditions, see footnote b in Table 3.4. (Key 1,5-COD 1,4-COD O COE 9 COA. (For abbreviations, see Scheme 3.9.) (FromHigashijima, M. Ho, S.-M. Nishimura, S. Bull. Chem. Soc. Jpn. 1992, 65, 2960. Reproduced with permission of Chemical Society of Japan.)...

Suffocation by carbon monoxide poisoning is another Lewis acid-base reaction. Now the carbon monoxide molecule, CO, can usurp the place of oxygen and attach Lewis-like to the Fe ions in haemoglobin. This attachment is stronger than oxygen is able to achieve, so the usurper blocks the attachment of oxygen. 

The carbon monoxide/hydrogen reaction is somewhat inefficient as a means of producing methane because the reaction liberates large quantities of heat. In addition, the methanation catalyst is troublesome and prone to poisoning by sulfur compounds and the decomposition of metals can destroy the catalyst. Thus, hydrogasification may be employed to minimize the need for methanation ... 

After secondary reforming it is important to reduce the amount of carbon monoxide by way of the shift reaction. A very low level is required because on modern plant any carbon monoxide entering the methanators is converted back to methane to avoid carbon monoxide poisoning of the ammonia synthesis catalyst. This back conversion (a) uses three moles of hydrogen for every mole of carbon monoxide. 

Modeling carbon monoxide poisoning is normally categorized under mass transport studies. Wang and Savinell [17] created a model of a carbon monoxide-poisoned anode that used variable membrane conductivity data of Springer et al. [15,16]. Only the mass transfer, proton migration, and electrochemical reaction of the anode catalyst layer were modeled. The local current production was found using ... 

Similarly to the carbon monoxide poisoning, in order to better understand the mechanism of hydrogen sulfide poisoning numerically, the rate of reactions should be represented mathematically. The kinetic parameters are given in Table 7.7 and were taken from the studies by Shi et al. [118] and Shah and Walsh [119]. 

There are several advantages associated with the MCFC system. First, the high operating temperature dramatically improves reaction kinetics and removes the need for a noble metal catalyst. The higher temperature also makes the cell less prone to carbon monoxide poisoning than lower... 

Carbon monoxide poisoning results from a reaction similar to carbonyl formation. CO molecules coordinate with Fe atoms in hemoglobin in the blood, displacing the O2 molecules normally carried by hemoglobin. The metal carbonyls themselves are also very poisonous. 

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