Carbon monoxide and hydrogen sulphide

Some indication of risk of employee exposure to airborne chemicals can be gauged from an analysis of the level of exposure for comparison with known human dose/ response data such as those for carbon monoxide and hydrogen sulphide listed in... 

From carbon monoxide and hydrogen sulphide Formaldehyde and sulphur, and thioformaldehyde and its polymers respectively, besides water,... 

Carbon monoxide and hydrogen sulphide are formed only underconditionsof incomplete combustion, e.g., in shaft kilns, and even then only in small amounts. 

In electrochemical cells sample oxidation produces an electric current proportional to the concentration of test substance. Sometimes interferences by other contaminants can be problematic and in general the method is poorer than IR. Portable and static instruments based on this method are available for specific chemicals, e.g. carbon monoxide, chlorine, hydrogen sulphide. 

For example, carbon dioxide from air or ethylene nitrogen oxides from nitrogen methanol from ethyl ether. In general, carbon dioxide, carbon monoxide, ammonia, hydrogen sulphide, mercaptans, ethane, ethylene, acetylene, propane and propylene are readily removed at 25°. In mixtures of gases, the more polar ones are preferentially adsorbed). 

A simple two-phase system at the valve inlet either flashing liquid and its vapour or non-flashing liquid with non-condensable gas. A noncondensable gas is a gas that cannot be condensed under the process conditions, typically air, nitrogen, hydrogen, carbon dioxide, carbon monoxide or hydrogen sulphide. 

Oxidases catalyse oxidations in presence of free oxygen. Unlike the dehydrogenases, they are unable to use methylene blue, cytochrome or similar hydrogen acceptors, and they also differ in their sensitivity to inhibitors. Thus, urethane and related narcotics have no action on oxidases, but cyanide, carbon monoxide or hydrogen sulphide in concentrations as low as 0-01 M to O OOl M inhibit them completely. This is ascribed to the fixation of an active metallic radicle, usually Fe, in the oxidase effector mechanism. 

The reactants, coal, water and oxygen are converted to hydrogen, carbon monoxide, carbon dioxide, methane, water vapour and hydrogen sulphide at a given temperature and pressure according to thermodynamic equilibria and the kinetics of gasification. A particular coal composition which is characteristic of a German hard coal was taken as a basis (Table I). 

The oxide is reduced by hydrogen, carbon monoxide, and by carbon. The reduction in an atmosphere of hydrogen begins at about 190° C.3 The oxide burns in fluorine, and when heated in hydrogen sulphide yields water and the monosulphide, NiS. Pellini (vide infra) ascribes the following graphical formula to the dioxide ... 

The action of hydrogen peroxide upon ferrous salts is interesting in view of the possible connection between ferrous salts acting as oxygen-carriers in the blood. The decomposition of the peroxide is hindered or poisoned by the presence of arsenious oxide, hydrogen sulphide, carbon monoxide, and other well-known poisons, and the subject is worthy of careful consideration.3... 

Certain compounds inhibit the activity of the respiratory chain by blocking the transfer of electrons at certain points. Rotenone and amytal inhibit electron transfer through Complex I. Antimycin A inhibits at the level of Complex III. Cytochrome oxidase activity is inhibited by carbon monoxide, cyanide and hydrogen sulphide. The prevention of electron transport by cyanide which is very rapidly absorbed is responsible for the high toxicity of this compound. 

---