Applications of Ethylene Oxide

The earliest important use of ethylene glycol was as antifreeze in automobile engines, but it had also been used earlier, converted to the dinitrate, as a component in low-freezing dynamite. Nowadays it is used mainly in the production of polyesters. 

Ethylene oxide is used in a variety of other applications such as nonionic surfactants, ethanolamines, and glycol ethers. 

Bismutii phosphomolybdate Phases present a-Bi203 3Mo03 p-Bi203 2Mo03 (most active) Y-Bi203 Mo03 

Uranyl antimonate Phase 1 (active) USb30io Phase 2 (inactive) USbOs 

Ammonia oxidation to nitrous oxide Iron oxide/bismuth oxide [Von Nagel, Zeit Electrochem 3 (1980) 754] Iron oxide/bismuth oxide/molybdenum oxide [Zawadski, Tram Faraday Soc Disc, No. 8 (1950) 140] 

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In addition, some essential food constituents react with formation of biologically inactive derivatives. Examples are riboflavin, pyridox-ine, niacin, folic acid, histidine or methionine. However, these reactions are not of importance under the conditions of the normal application of ethylene oxide or propylene oxide. 

Sodium dodecylbenzenesulfonate is undoubtedly the anionic surfactant used in the greatest amount because it is the basic component in almost all laundry and dishwashing detergents in powder and liquid forms. However, alcohol and alcohol ether sulfates are the more versatile anionic surfactants because their properties vary, with the alkyl chain, with the number of moles of ethylene oxide added to the base alcohol and with the cation. Consequently, alcohol and alcohol ether sulfates are used in almost all scientific, consumer, and industrial applications. 

The polyoxyethylene group is obtained by addition of ethylene oxide to fatty alcohols, mostly with an alkalic catalyst such as NaOH or NaOCH3, giving a broad polyoxyethylene oxide distribution. For special applications the ethoxyl-ation can be catalyzed by Lewis acids [11] to achieve a narrow range distribution. Other narrow range catalysts can also be used to improve certain properties. 

Booth C, Yu GE, Nace VM (1997) Block copolymers of ethylene oxide and 1,2-butylene oxide. In Alexandridis P, Lindman B (eds) Amphiphilic block copolymers self-asssembly and applications. Elsevier, Amsterdam... 

Commercial mixtures of surfactants consist of several tens to hundreds of homologues oligomers and isomers. Their separation and quantification is complicated and a cumbersome task. Detection, identification and quantification of these compounds in aqueous solutions, even in the form of matrix-free standards, present the analyst with considerable problems. The low volatility and high polarity of some surfactants and their metabolites hamper the application of gas-chromatographic (GC) methods. GC is directly applicable only for surfactants with a low number of ethylene oxide groups and to some relatively volatile metabolic products, while the analysis of higher-molecular-mass oligomers is severely limited and requires adequate derivatisation. 

The use of aqueous foams to control fume or vapour release from reactive chemicals is discussed. An acid-resistant foam NF2 controlled fume emission from 35% and 65% oleum, and from titanium tetrachloride, but was not effective for sulfur trioxide and chlorosulfuric acid. An alcohol-resistant foam NF1 suppressed ammonia vapour emission by 80%, and Universal fire foam reduced evaporation of ethylene oxide, vinyl chloride and methanethiol, and reduced vapour emission of 1,3-butadiene by 60%. Safety aspects of foam blanketing are discussed [1]. Equipment and application techniques are covered in some detail [2],... 

Contact of solutions of ethylene oxide with the skin of human volunteers caused characteristic burns after a latent period of 1-5 hours, effects were edema and erythema and progression to vesiculation, with a tendency to coalescence into blebs, and desquamation. Complete healing without treatment usually occurred within 21 days with, in some cases, residual brown pigmentation. Application of the liquid to the skin caused frostbite three of the eight volunteers were said to have become sensitized to ethylene oxide solutions. The undiluted liquid or solutions may cause severe eye irritation or damage. 

Table 9.5 lists the uses of ethylene oxide. Ethylene glycol is eventually used in two primary types of end products polyesters and antifreeze. About half the ethylene glycol is used for each end product. Poly(ethylene terephthalate) is the leading synthetic fiber and has other important applications in plastic film and bottles. Ethylene glycol is a common antifreezing agent especially in automobile radiators. 

Several other possibilities exist for the mechanism of hydrocarbon oxidation, and in the application to ethylene oxidation, this isotopic determination of the reaction rate involving H and D was the main diagnostic of the mechanism determination for this reaction on Pt. 

In 1937 the first commercial application of the Lefort direct ethylene oxidation to ethylene oxide [75-21 -8] followed by hydrolysis of ethylene oxide became, and remains in the 1990s, the main commercial source of ethylene glycol production (1) (see Ethylene OXIDE). Ethylene oxide hydrolysis proceeds with... 

With very few exceptions, quantitative epoxide assay techniques currently in use are derived from the reeotion of ethylene oxides with halogen adds, notably hydrochloric acid and hydrobromio add, in a variety of solvents. Acid uptake may be determined by any of several reliable procedures. These include titration with standard base8 nr back-titration with standard acid.744 The end-point may be detected visually in the presence of suitable acid-base indicators, or by the more precise technique of potontionaetry.447.4 -470 A useful alternative, applicable in the presence of easily hydrolysed substances or of amines that buffer the end-point, is the technique of argentiometry. In this procedure excess of halide ion is titrated with silver nitrate in tV presence of ferric thiocyanate indicator,470 1884 or potentiometri-cally.188 ... 

The kinetics of the reaction between ethylene oxide and various alcohols has been a subject of some interest as an application of the theory of consecutive reactions. 8 1,M 12l7>1SW With ethanol, for example, a sequence of steps may be written in the manner depicted in Rq. (650), and a complex kinetic expression derived for the rate of ethylene oxide disappearance. 

Poly(ethylene oxide) resins are safely used in numerous pharmaceutical and personal-care applications. Poly(ethylene oxide) resins show a low order toxicity in animal studies by all routes of exposure. Because of their high molecular weight, they are poorly adsorbed from the gastrointestinal tract and completely... 

Nonionic surfactants are also used in substantial amounts in laundry detergents and in automatic dishwashing detergents, both applications reflecting in particular their generally lower sudsing characteristics than the anionics. Commercially important examples uf the nonionics include the alkyl ethoxylates, the ethoxylated alkyl phenols, the fatly acid ethanol amides, and complex polymers of ethylene oxide, propylene oxide, and alcohols. 

Nonionic Surface-Active Agents. Approximately 14% of the ethylene oxide consumed in the United States is used in the manufacture of nonionic surfactants. These are derived by addition of ethylene oxide to fatty alcohols, alkylphenols (qv), tall oil, alkyl mercaptans, and various polyols such as polypropylene glycol), sorbitol, mannitol, and cellulose. They are used in household detergent formulations, industrial surfactant applications, in emulsion polymerization, textiles, paper manufacturing and recycling, and for many other applications (281). 

Ethanolamines. These are produced by the reaction of ethylene oxide and ammonia (see Alkanolamines). Approximately one-third of the production is used in detergents. Other applications include natural gas purification, cosmetics, metalworking, textiles, and chemical intermediates (282). 

Poly(ethylene oxide) (PEO) macromonomers constitute a new class of surface active monomers which give, by emulsifier-free emulsion polymerization or copolymerization, stable polymer dispersions and comb-like materials with very interesting properties due to the exceptional properties of ethylene oxide (EO) side chains. They are a basis for a number of various applications which take advantage of the binding properties of PEO [39], its hydrophilic and amphipathic behavior [40], as well as its bio compatibility and non-absorbing character towards proteins [41]. Various types of PEO macromonomers have been proposed and among them the most popular are the acrylates and methacrylates [42]. 

In other oxygen applications, metal fabrication involves cutting and welding with an oxygen-acetylene torch. Chemical manufacture use includes the formation of ethylene oxide, acrylic acid, propylene oxide, and vinyl acetate. Miscellaneous uses include sewage treatment, aeration, pulp and paper bleaching, and missile fuel. 

The following table shows the effect of ethylene oxide upon the solubility of the formulation. From these results, it can be readily understood why the 40 percent ethoxylate (3 mole) is usually used for this application. 

Polyoxymethylene (POM) is, again, a crystalline polymer, with a melting point of about 180 °C. Its mechanical properties enable it to gradually replace metals in a number of applications. Many technical parts are being made from POM, such as gear wheels, bars, automotive accessories, parts of several apparatuses and machines. The polymer is used as such (e.g. Delrin ), but also as a copolymer with a small amount of ethylene oxide (e.g. Celcon and Hostaform ). 

Several other anionic surfactants are commercially available, such as sulfosuccinates, isethionates, and taurates, and these are sometimes used for special applications. The carboxylates and sulfates are sometimes modified by the incorporation of a few moles of ethylene oxide (referred to as ether carboxylates and ether sulfates, respectively). 

This class of surfactants has possibly the widest range of use of any anionic surfactant. It is found in almost every product where foaming is desirable, in industrial, household and personal care applications. Alkyl ether sulphates are described in terms of their parent alcohol and the degree of ethoxylation. Thus, sodium laureth-2 is the sodium salt of a sulphated (predominantly) C12 alcohol, with an average of 2 mol of ethylene oxide added. Often, the alcohol is assumed to be the typical C12-14 and the surfactant simply called a 2-or 3-mol ether sulphate. 

Ether carboxylates are a very versatile class of surfactants, used in diverse applications from mild personal care formulations to lubricants and cutting fluids. They are interrupted soaps, with the addition of a number of ethylene oxide groups between the alkyl chain and the carboxylate group. The additional solubility imparted by the EO groups gives much greater resistance to hardness and reduced irritancy compared to soap. 

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