Benzene combustion constants

Coincident with the development of sampling procedures were the constant iterative improvements in extraction, separation, identification and quantitation of organic compounds. Special emphasis was placed on selected compound classes such as the polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), chlorinated benzenes, and chlorinated dibenzo-p-dioxins (dioxins). The best available procedures were used to determine these components because they have known acute or chronic effects and previous studies suggested that they might be present in effluents from the combustion of coal alone and combination coal/RDF. 

Nitro derivative of benzene Heat of combustion (at constant volume), kcal/mole Heat of formation (for amorphous carbon), kcal/mole... 

Properties Colorless, hygroscopic liquid nearly odorless slightly bitter taste. Bp 189C, mp 18.5C, d 1.10(20/20C), specific heat 0.7 cal/g K, flashp 203F (95C) (OC), dielectric constant 48.9 (20C). E2xtremely powerful aprotic solvent. Soluble in water, alcohol, benzene, acetone, chloroform. Combustible. 

Properties White flakes with sweet clover odor. Bp 213C, mp 56C, d 1.0293 (65C), viscosity 1.04 cP (65C), dielectric constant 2.8, absorbs UV light in range 2800-3000A. Soluble in benzene and alcohol insoluble in water. Combustible. 

Deliquescent, orthorhombic, elongated, six-sided tablets from dimethyl phthalate. dj 1.282. mp 45-46. bp0J 83. Fomin of dicyandiamide begins at 122. Dipole moment in benzene at 2Cryoscopic constant (water) 26.8-28.4. Sp ht 0.547 cal/g/ C between 0° and 39. Heat of formation 14.05 kcal/mole (25 ) heat of combustion —176-4 kcal/-mole (25 ) heat of fusion 2.1 kcal/mole. Heat of vaporization 16.4 kcal/mole. Soly (g/100 g soln) in water at 15 77.5, at 43 100 in butanol at 20 28.8, in methyl ethyl ketone 50.5, in ethyl acetate 42.4. Sol in alcohols, phenols, amines, ethers, ketones. Very sparingly sol in benzene, haJogeaated hydrocarbons. Practically insol in cyclohexane. Solid cyanamide should be stored in a cool, dry place. Polymerizes at 122. Optimum pH for storage of solns is 4, Attacks various metals. Solns can be stored in grass provided they are stabilized with phosphoric, acetic, sulfuric, or boric acid. LDM in rats 125 mg /kg orally. 

Colorless to yellow, oily liquid. Pyrophoric in air burns to FejOj. Dec by light to Fe/cO), and CO. mp —20". bp 103, dj° 1.46-1.52 rtg 1.453. Critical temp 285-288 critical pressure 29.6 atm. Flash pi —15. Heat capacity at constant pressure (14 ) 56.9 cal/mole/ C. Latent heat of fusion 3161 cal/mol latent heat of vaporization 9.6kcal/-mole. Heat of combustion —386.9 kcal/mole heat of formation [Fe(CO),0iq)] —182.6 kcal/mole. Practically insol in water readily sol in most organic solvents including ether, benzene, petr ether, acetone, ethyl acetate, carbon tetrachloride, carbon disulfide slightly sol in alcohol practically insol in liquid ammonia. Protect from light and air, LDM in mice, rats 2.19, 0.91 mg/1 inhalation, exposure for 30 min. (Sunderman). 

The effects of increasing space velocity have been demonstrated by Vassileva and co-workers [10]. The combustion of benzene over a 0.5 wt% Pd/30% V2O5/AI2O3 catalyst for space velocities of 330,2,000 and 5,000 h at a constant oxygen to benzene molar ratio of ca. 7.5. The effects of varying space velocity are shown in figure 2. However, it should be noted that these data indicate that there may be an induction period for this catalyst, which is most marked at the lowest space velocity investigated. 

It can be seen that there is a significant decrease in the temperature required for combustion to occur with the hydrophobic catalysts. A detailed kinetic study of the combustion process indicated that the surface reduction rate constant, ki, in the Mars-van Krevelan mechanism increases with temperature faster than the surface re-oxidation rate constant, ks. That is, the surface concentration of adsorbed oxygen (O2) is higher than that of (CnHn-O) at higher temperatures. This occurs in spite of the fact that ki is more sensitive to variations in temperature than ka. The ratio ki/ks for a Pt/hydrophobic catalyst in the combustion of benzene, toluene and xylene at 90-130°C was calculated to be in the range 466-3880, which can be compared to 24-2490 for a conventional hydrophilic catalyst (Pt-Ni/AhOa) in the oxidation of benzene and n-hexane at 140-221°C [34]. 

This means that when 1 mole of liquid benzene reacts with 7 moles of oxygen, forming 3 moles of liquid water and 6 moles of carbon dioxide at constant pressure and constant temperature, 781 kcal are evolved therefore, the enthalpy of the 3 moles of HjOfl) and 6 moles of C02less than the enthalpy of 1 mole of CsHe(0 and 74 moles of 02(g). Since AH = HpmductB Hreactants. AH is negative for the combustion of C6Hg(i). For the decomposition of nickel oxide at 25.0 C,... 

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