Ethanol

Abstract

ETHANOL 1 a Refs. 6-14. b To convert kPa to atm, divide by 101.3. c To convert J to cal, divide by 4.184. d To convert C·m to debye, divide by 3.336 × 10 −30 (esu = D × 10 −18 ) .A summary of physical properties of ethyl alcohol is presented in Table 1. Detailed information on the vapor pressure, density, and viscosity of ethanol can be obtained from References 6-14. A listing of selected binary and ternary azeotropes of ethanol is compiled in Reference 15. Chemical PropertiesThe chemistry of ethyl alcohol is largely that of the hydroxyl group, namely, reactions of dehydration, dehydrogenation, oxidation, and esterification. The hydrogen atom of the hydroxyl group can be replaced by an active metal, such as sodium, potassium, and calcium, to form a metal ethoxide (ethylate) with the evolution of hydrogen gas (see Alkoxides, metal). 2 C 2 H 5 OH + 2 M −→ 2 C 2 H 5 OM + H 2 Sodium ethoxide [141-52-6] can be prepared by the reaction of absolute ethyl alcohol and sodium, or by refluxing absolute ethyl alcohol with anhydrous sodium hydroxide (16): CH 3 CH 2 OH + NaOH −→ CH 3 CH 2 ONa + H 2 O ETHANOL 3Commercially, water is removed by azeotropic distillation with benzene (17). Sodium ethoxide precipitates upon addition of anhydrous acetone (18). This strong base hydrolyzes readily to give ethyl alcohol and sodium and hydroxyl ions.Sodium ethoxide can also be prepared by the reaction of sodium amalgam with ethyl alcohol.Sodium ethoxide is used in organic synthesis as a condensing and reducing agent. The reaction between sodium ethoxide and sulfur monochloride yields diethyl thiosulfite (19).2 CH 3 CH 2 ONa + S 2 Cl 2 −→ (CH3CH2O) 2 S 2 + 2 NaCl Barbiturates (Veronal, Barbital, Luminal, Amytal), ethyl orthoformate, and other chemicals are produced commercially from sodium ethoxide.Aluminum and magnesium also react to form ethoxides, but the reaction must be catalyzed by amalgamating the metal (adding a small amount of mercury).6 CH 3 CH 2 OH + 2 Al −→ 2 (CH3CH2O) 3 Al + 3 H 2 2 CH 3 CH 2 OH + Mg −→ (CH3CH2O) 2 Mg + H 2 Well-cleaned aluminum filings react at room temperature in the presence of mercuric chloride (20, 21). In an autoclave, metallic aluminum and ethyl alcohol react without a catalyst at 120 • C (22). The reaction can also be promoted by the addition of sodium ethoxide (23). Aluminum should be avoided as a material of construction for ethanol service.Other reactions involving the hydrogen atom of the hydroxyl group in ethyl alcohol include the opening of epoxide rings to form hydroxy ethers, and the addition to acetylene [74-86-2] to form ethyl vinyl ether [104-92-2].These reactions are carried out in the presence of acidic and basic catalysts. The acid-catalyzed addition of ethyl alcohol to acetylene or to a vinyl ether produces acetals (diethers of 1,1-dihydroxyethane). The acid-catalyzed reaction of ethyl alcohol with an aldehyde or ketone also gives acetals.The hydroxyl group can be replaced by halogens from inorganic acid halides or phosphorus halides to give two different products, ethyl esters of the...

Continuous Upgrading of Fast Pyrolysis Oil by Simultaneous Esterification and Hydrogenation

“…Similarly, isopropanol would be sourced from the petroleum derived feedstock propylene . Ethanol would be sourced from corn in the United States or sugar cane in Brazil because these countries and the associated biomass are the sources for ethanol production . The significantly lower price of methanol (∼$0.58/gal) suggests it would be more practical to use compared to ethanol (∼$1.5–1.7/gal) or isopropanol. , If use of isopropanol is proven feasible on a large scale (i.e., as effective as H 2 ), then its recovery and regeneration (i.e., hydrogenation of acetone back to isopropanol in a separate reactor) would be critical because it is significantly more expensive than methanol (∼$2.30/gal)…”

Sustainable scale-up of negative emissions technologies and practices: where to focus

“…A purification unit is required to meet the commercial specifications of ethanol. Although several technologies such as membranes or molecular sieves could help reduce the energy consumption of the ethanol separation process, this step is typically carried out in a distillation unit, which accounts for 50-80% of the total energy input (Logsdon 2004). Therefore, the main CO 2 source in a conventional ethanol plant is the cogeneration unit, designed to supply heat and power to the system (Carminati et al 2019).…”

Potential routes for thermochemical biorefineries

“…101,139 Industrial production of ethyl acetate can be conducted in batch or CSTR reactors along with several distillation columns. 140 Th e same considerations as in the esterifi cation with methanol are applicable (depending on the syngas composition and plant confi guration) normally leads to a net production of H 2 . Th e carbonylation of DME occurs in the presence of some kinds of zeolites, for example, mordenites, ferrierites and ZSM-35, at reaction conditions of up to 100 bar and 150-200ºC.…”