Micro hydrogen combustion

Catalytic Hydrogen Combustion 1 [CHC 1] Single-channel Micro Reactor for Catalytic Hydrogen Combustion... 

The deterrnination of hydrogen content of an organic compound consists of complete combustion of a known quantity of the material to produce water and carbon dioxide, and deterrnination of the amount of water. The amount of hydrogen present in the initial material is calculated from the amount of water produced. This technique can be performed on macro (0.1—0.2 g), micro (2—10 mg), or submicro (0.02—0.2 mg) scale. Micro deterrninations are the most common. There are many variations of the method of combustion and deterrnination of water (221,222). The oldest and probably most reUable technique for water deterrnination is a gravimetric one where the water is absorbed onto a desiccant, such as magnesium perchlorate. In the macro technique, which is the most accurate, hydrogen content of a compound can be routinely deterrnined to within 0.02%. Instmmental methods, such as gas chromatography (qv) (223) and mass spectrometry (qv) (224), can also be used to determine water of combustion. 

Wright, The Rapid Micro Combustion Determination of Carbon, Hydrogen Nitrogen in High Explosives", Explosivst 14 (12), 274-6 (1966) CA 66, 97068 (1967) 43) Anon,... 

Elemental analysis of the oils was carried out as follows carbon and hydrogen by micro combustion using a Perkin-Elmer 240 Elemental Analyzer sulphur by X-ray fluorescence using a Telsec Lab X-100 apparatus nitrogen by chemiluminescence using a Dohrmann DN-10 apparatus. 

Analyses. Analyses of ash, carbon, and hydrogen by combustion, and nitrogen by Dumas or micro-Kjeldahl methods (17) were obtained from Schwarzkopf Microanalytical Laboratory, Woodside, N. Y. 11377. 

The uncertainties for the analytical methods are as follows ash by combustion residue, 0.3% absolute C, 0.05 mg C H, 0.3% absolute and N, by Dumas, 5 /A or by micro-Kjeldahl, 1 g (18). The large uncertainties in the measurements of carbon and hydrogen limit the usefulness of data for these elements for very small samples. 

Compn of TeNCbz prepd at PicArsn by Livingston(Ref 3) was established by detg total nitrogen content(using micro-Kjeldahl app), nitro-nitrogen content(by titanous chloride method) and carbon-hydrogen content(by micro -combustion method)... 

In a further semi-micro combustion method85 for the determination of carbon and hydrogen in low boiling compounds the decomposition product of AgMn04 was used as combustion catalyst. 

Deflagration is the type of combustion with a subsonic burning velocity level. It occurs under non-adiabatic conditions and at densities lower than that of the unbumt mixture. Its propagation mechanism is conduction heating and free radical diffusion. Only fuel-air gas clouds at around stoichiometric mixture imply high flame front velocities and maximum expansion upon ignition, i.e., the ratio of the density of unbumt mixture to that of the reaction products, which is about 7 - 8 for hydrocarbons (in reality smaller by up to 50 % because of non-ideal micro-mixture), but < 1 for hydrogen. 

After combustion has been carried out in an oxygen-hydrogen flame, the inorganic mineralization products are determined as chloride ions. This can be carried out by a number of different methods, among which micro-coulometry has been proved especially successful. 

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