Ethanol freezing

Ethyl alcohol (ethanol, freezing point -114.1°C, boiling point 78.3°C, density 0.7893, flashpoint 14°C) is also named, industrial alcohol, grain alcohol, and alcohol. Ethyl alcohol is miscible in all proportions with water or with ether. When ignited, ethyl alcohol burns in air with a pale blue, transparent flame, producing water and carbon dioxide. The vapor forms an explosive mixture with air and is used in some internal combustion engines under compression as a fuel such mixtures are frequently referred to as gasohol. 

A cooling bath is prepared in a laboratory by mixing chunks of solid CO2 with ethanol. C02(s) sublimes at — 78.5°C to C02(g). Ethanol freezes at —114.5°C and boils at +78.4°C. State the temperature of this cooling bath and describe what will be seen when it is prepared under ordinary laboratory conditions. 

Freeze slowly by adding vials to either a standard freezer box that has been packed with cotton or a commercially available ethanol freezing container and leave it in a -70°C freezer overnight. 

Steam distillation, extraction with non-polar solvents, pressing and evaporation of solvent produce an essential oil known as a concrete, which is a mixture of essential oil, various lipophilic substances and mainly waxes. The accompanying substances are separated by dissolution in hot ethanol, freezing and filtration and the essential oil thus obtained is absolute. 

An absolute is obtained by the extraction of a concrete with ethanol. Freezing the ethanol extract to lower temperatures (e.g., — 15°C) solidifies waxes and subsequent cold filtration yields a liquid extract. A dark-colored, liquid or semisolid, and highly fragrant oil is obtained after the evaporation of ethanol under vacuum. 

It will be a little tricky but one can also try to purify by freezing I The sassafras oil is thrown into the freezer to chill. Safrole itself freezes at -14°C so anything that starts to freeze prior to that can be cold filtered in a prechilled vacuum filtration setup. The filtrate goes back in the freezer until -14°C is reached and the mother lode of safrole freezes up. This again is filtered cold but this time the frozen mass of safrole crystals are washed with some ice cold methanol or ethanol (preferably at -14°C) to wash away the unfrozen high-boiling constituents. 

Pish silage prepared by autolysis of rainbow trout viscera waste was investigated as a substrate for the plastein reaction using pepsin (pH 5.0), papain (pH 6—7), and chymotrypsin (pH 8.0) at 37°C for 24 h (152). Precipitation with ethanol was the preferred recovery method. Concentration of the protein hydrolysate by open-pan evaporation at 60°C gave equivalent yields and color of the final plastein to those of the freeze-dried hydrolysate. 

The development of freeze-drying for the production of blood derivatives was pioneered during World War II (96,97). It is used for the stabilization of coagulation factor (98,99) and intravenous immunoglobulin (IgG iv) products, and also for the removal of ethanol from intramuscular immunoglobulin (IgG im) solutions prior to their final formulation (Fig. 2). 

Like brines, alcohols were readily available and widely used as antifreeze Hquids in the early 1900s. Both methanol and ethanol offer exceUent heat transfer and efficient freeze point depression. However, the alcohols have the distinct disadvantage of their low boiling points. During the summer months when the engines operate hot, significant amounts of the alcohols are lost because of evaporation. These evaporative losses result in cosdy make-up requirements. Additionally, the alcohols have very low flash points and potentially flammable vapors. These safety concerns have, particularly in recent years, caused the use of alcohols to be completely discontinued for most heat-transfer systems. 

Superdex and prepacked Superdex columns are supplied in 20% ethanol. All Superdex may be autoclaved repeatedly at pH 7, 120°C without significant changes in porosity or rigidity. Freezing and thawing of Superdex-based gels may result in disruption of the bead structure and should be avoided. 

The compound is very soluble in most organic solvents. In order to get a high recovery, it is necessary to complete the crystallization in the deep freeze. From aqueous ethanol the aldehyde crystallized in high yield as the hemihydrate, m.p. 95°. 

Vodka is advertised to be 80 proof. That means that the ethanol (C2H5OH) concentration is 40% (two significant figures) by volume. Assuming the density of the solution to be 1.0 g/mL, what is the freezing point of vodka The density of ethanol is 0.789 g/mL. 

Mono ethanol amine (MEA). A solvent used to dissolve other laundry detergent ingredients. It also lowers the freezing point of liquid laundry products to allow them to be transported in cold weather. 

C12-0065. Estimate the freezing point of a wine that is 12% by mass ethanol. (Ignore all other solutes.)... 

C12-0097. When an aqueous solution cools to low temperature, part of the water freezes as pure ice. What happens to the freezing point of the remaining solution when this occurs A glass of wine placed in a freezer at -10 C for a very long time forms some ice crystals but does not completely freeze. Compute the molality of ethanol in the remaining liquid phase. 

Preparation of the alcohol insoluble solids (AIS) The content of the can was drained and the carrot cubes were immediately frozen in hquid nitrogen, freeze-dried and milled. Carrot powder (ca. 10 g) was mixed with 200 ml 80% ethanol previously heated to 60°C. After filtration the residue was extracted with ethanol until the filtrate was colorless (5 times) and gave negative reaction with phenol-sulfuric acid test (Dubois et al., 1956). 

Figure 14-2. Some organic anti-freeze agents methanol, ethanol, 2-propanol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol.

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