Ethanol flammability limits

Some organic compounds can be in solution with water and the mixture may still be a flammable mixture. The vapors above these mixtures such as ethanol, methanol, or acetone can form flammable mixtures with air. Bodurtha [39] and Albaugh and Pratt [47] discuss the use of Raoult s law (activity coefficients) in evaluating the effects. Figures 7-52A and B illustrate the vapor-liquid data for ethyl alcohol and the flash point of various concentrations, the shaded area of flammability limits, and the UEL. Note that some of the plots are calculated and bear experimental data verification. 

A critical safety issue of using diesel-ethanol blends relates to flashpoint and flammability. E-diesel blends containing 10-15% ethanol have the vapor pressure and flammability limits of ethanol. This means that ethanol concentrations in enclosed spaces such as fuel storage and vehicle fuel tanks are flammable over the temperature range 13-42 °C. Thus, there are higher risks of fire and explosion than with diesel fuel, or even gasoline. Other vehicle performance-related concerns are (a) a decreased maximum power (b) an increased incidence of fuel pump vapor lock and (c) a reduced fuel pump and fuel injector life due to the decreased lubricity of ethanol. 

Highly poisonous, odorless, colorless, tasteless gas. Very flammable, burns in air with a bright blue flame. Ignition pt in air 700. mp-205.0. bp-191.5°. d - M (liq) 0.814. d (gas) 0.968 (air — 1.000). dg at 760 mm 1.250 g/liter. The top pressure is 1500 psi. Flammable limits in air 12 to 75 vol %. Crit press 35 atm, crit temp — 139. Heat capacity at 20° 6.95 cal/mole/ C. Heal value per m3 3033 keal. Heat of formation — 26.39 kcal/mol. Dec into carbon and carhon dioxide between 400 and 700°, at lower temp when in contact with catalytic surfaces. Above 800° the equilibrium reaction favors CO formation. Hopcalite, a mixture of the oxides of manganese and copper, catalyzes the decompn at room temp, as does Pd on silica gel. Sparingly sol in water 3.3 ml /100 ml HjO at O 2.3 ml/100 ml HjO at 2(T freely absorbed by a coned soln of cuprous chloride in HC1 or in NHjOH. Appreciably sol in some organic solvents, such as ethyl acetate. CHCI. acetic acid- The soly in methanol and ethanol is about 7 times as great as the soly in water. 

Ethylene (Ethene or Elayl), H2C CH2 mw 28.05 colorless, flammable, dangerous to handle gas with characteristic sweet odor and taste sp gr 0.975 (air = 1.0), mp —169.4°, bp —103.8°, flash p —136°C explosive limits in air, % by vol, lower 3.0 upper 34.0 si sol in w, more in ale sol in eth. Ethylene is a major component of petroleum refinery gas from cracking units, and is sometimes recovered therefrom by distillation or other means. Some pure ethylene is produced by passing hot ethanol vapors over a catalyst, such as activated alumina (Ref 4). Its laboratory prepn consists of heating ethanol in definite proportions with sulfuric acid of certain concns. By using a 90% acid and 90% ale, ethylene can be produced in a regular stream at a yield of 84 to 85% of theory (Ref 2). 

Properties Colorless liquid. D 0.858 (25/25C), bp 34.8C, fp -117.6C, refr index 1.374 (25C), flash p -26F (-32.3C), autoigntemp 1100F (593C). Slightly soluble in water soluble in ethanol and ether. Hazard Highly flammable, fire and explosion risk, explosive limits in air 2.8-10.7%. 

ETHANOL (64-17-5) CjHjOH Flammable liquid. Forms explosive mixture with air [explosion limits in air (% by volume) 3.3 to 19 flash point 55°F/13°C 68°F/20°C (80%) 72°F/22°C (60%) 79°F/26°C autoignition temp 685°F/363°C Fire Rating 3], Reacts, possibly violently, with strong oxidizers, strong acids bases, strong peroxides acetic anhydride, acetyl bromide, acetyl chloride, aliphatic amines, bromine pentafluoride, calcium oxide (quicklime), cesium oxide, chloryl perchlorate, disulfiiryl difluoride, ethylene glycol methyl ether, iodine heptafluoride, isocyanates, nitrosyl perchlorate, perchlorates, platinum, platinum-black catalyst potassium-tert-butoxide, potassium, potassium oxide, potassium peroxide, potassium superoxide phosphorus (III) oxide, silver nitrate, silver oxide, sulfuric acid, oleum, sodium, sodium hydrazide, sodium peroxide, sulfinyl cyanamide, tetrachlorosilane, s-triazine-... 

A wide variety of organic solvents will work, but availability, cost, toxicity and flammability will limit the choices. Research has shown that chloroform is the best solvent it extracts about 98% of the cannabinoids with one half hour of shaking. Light petroleum ether extracts about 90%. But ethanol (grain alcohol) is most often used. It is easier to obtain and extracts a high percentage as well. Ninety-five percent ethanol is hard to obtain. 

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