Carbon black evolved gases

A further surface treatment was chlorination of a carbon black and an activated carbon with CI2 gas at 723 K for 6 hours [96]. Saturation is nearly reached at this reaction time. HCl is evolved in the chlorination of carbon blacks, in most cases in a molar quantity that slightly exceeds the quantity of chlorine fixed in the reaction, suggesting that this is a substitution reaction [97]. The bonding mechanism is less clear in the case of activated carbons. The catalytic activity of the activated carbon Anthralur decreased on chlorination, while a small catalytic activity was established in the case of the carbon black Corax 3 (Table 7.7). 

A mixture of ThOg and calcined carbon black (0.24% ash) or graphite powder (0.33% ash), in quantities corresponding to the above equations, is made into a paste with a small amount of water and starch, and evaporated with stirring (graphite is preferred to carbon black because of its smaller volume). The lumps of dried material are placed in a crucible by means of a porcelain spatula their large size prevents them from being carried out of the crucible by the CO gas evolved in the process. 

Cellulose(CEL)- and polyacrylonitrile(PAN)-based ACF s and coconut-shell granular activated carbons (AC) were used in this study. Also nonporous carbon black(NPC) whose surface area Is 81 m g" was examined by in situ XRD for comparison. The adsorption Isotherms of water at 298 K and N2 at 77 K on samples were measured gravimetrically. The ACF sample was pre-evacuated at 383 K and 1 mPa for 15 h prior to the adsorption. The evolved gas analyses (EGA) of ACF samples preheated at 373 K under 1 mPa for 15 h were carried out at a heating rate of 10 K min with the aid of a mass filter(ULVAC, MSQ-150A). The elemental analysis for the nitrogen atom of the ACF samples was done the ratios of nitrogen to carbon in wt. % of CEL and PAN were 2 and 6-7, respectively. 

CO2 ( fixed air ), prepared by Joseph Black (aged 24-26), was the first gas other than air to be characterized (i) chalk when heated lost weight and evolved CO2 (genesis of quantitative gravimetric analysis), and (ii) action of acids on carbonates liberates CO2. 

The natural niobites and tantalites axe usually black, and form iso-morphous, prismatic crystals, belonging to the rhombic system. They are easily fusible and very brittle, presenting an uneven fracture. Their density increases from 5-2 to 8 2 with increase in tantalum content.6 When heated to redness in vacuo they evolve small quantities of gas, which consists of carbon dioxide, nitrogen and oxygen.7 Small quantities of helium have also been found occluded in them. 

Black powder, the oldest explosive and propellant kno wn, consists of a mechanical mixt of saltpeter, charcoal and sulfur in proportions varying with the purpose. Here, saltpeter is the oxygen producer, while charcoal is the combustible material. The object of sulfur is to make the powder readily inflammable and to form, on burning, K or Na sulfide (by reaction with K or Na nitrate) so as to prevent part of the C02 from forming K or Na carbonate, which would, of course, mean a reduction in the amt of gas evolved. Sulfur also imparts the neeessary tenacity and density to the powder mass(Ref 34,p 191)... 

Ruthenium Dicarbonyl, Ru(CO)a.—Ruthenium, like iron, yields a carbonyl derivative. It is obtained as an orange-yellow deposit upon subjecting ruthenium black to the action of carbon monoxide at 300° C. under a pressure of 400 atmospheres. The product is extracted from the residue by solution in alcohol. It is insoluble in benzene and in hydrochloric acid, but soluble in nitric acid and in bromine, gas being evolved. When heated, a mirror of metallic ruthenium is produced.5 In contradistinction to the other carbonyls of this group of metals ruthenium dicarbonyl is not volatile. 

---