Oxides ethylene

Ethylene oxide [75-21-8] was first prepared in 1859 by Wurt2 from 2-chloroethanol (ethylene chlorohydrin) and aqueous potassium hydroxide (1). He later attempted to produce ethylene oxide by direct oxidation but did not succeed (2). Many other researchers were also unsuccesshil (3—6). In 1931, Lefort achieved direct oxidation of ethylene to ethylene oxide using a silver catalyst (7,8). Although early manufacture of ethylene oxide was accompHshed by the chlorohydrin process, the direct oxidation process has been used almost exclusively since 1940. Today about 9.6 x 10 t of ethylene oxide are produced each year worldwide. The primary use for ethylene oxide is in the manufacture of derivatives such as ethylene glycol, surfactants, and ethanolamines. 

Ethylene oxide is a colorless gas that condenses at low temperatures into a mobile Hquid. It is miscible in all proportions with water, alcohol, ether, and most organic solvents. Its vapors are flammable and explosive. The physical properties of ethylene oxide are summarized in Tables 1—7. 

Kirk-Othmer Encyclopedia of Chemical Technology (4th Edition) 

Wt% Mol % Specific gravity at 10/10°C Ereezing point, °C Boiling point, °C 

Ethylene oxide is a highly active intermediate. It reacts with all compounds that have a labile hydrogen such as water, alcohols, organic acids, and amines. The epoxide ring opens, and a new compound with a hydroxyethyl group is produced. The addition of a hydroxyethyl group increases the water solubility of the resulting compound. Eurther reaction of ethylene oxide produces polyethylene oxide derivatives with increased water solubility. 

Many commercial products are derived from ethylene oxide by reacting with different reagents. The following reviews the production and the utility of these chemicals. 

Ethylene glycol (EG) is colorless syrupy liquid, and is very soluble in water. The boiling and the freezing points of ethylene glycol are 197.2° and -13.2°C, respectively. 

Current world production of ethylene glycol is approximately 15 billion pounds. Most of that is used for producing polyethylene terephtha-late (PET) resins (for fiber, film, bottles), antifreeze, and other products. Approximately 50% of the world EG was consumed in the manufacture of polyester fibers and another 25% went into the antifreeze. 

EG consumption in the US was nearly 1/3 of the world s. The use pattern, however, is different about 50% of EG is consumed in antifreeze. The US production of ethylene glycol was 5.55 billion pounds in 1994, the 30th largest volume chemical. 

Ethylene Oxide. Essentially all ethylene oxide produced industrially is manufactured by the direct oxidation of ethylene catalyzed by silver 867,887-889 

This oxidation is unique, since only silver is capable of epoxidizing ethylene, and silver is active only in the oxidation of ethylene. A low-surface-area a-alumina is usually applied to support about 10-15% silver. Organic halides (1,2-dichloro-ethane, ethyl and vinyl chloride) are added as moderators, and additives (Cs, Ba) are also used to increase selectivity. At present selectivity in industrial oxidations is about 80%. 

Several processes based on air or oxygen have been developed.890-895 Oxidation with air (260-280°C) or oxygen (230°C) is carried out at about 15-25 atm at a limited conversion (about 10-15%) to achieve the highest selectivity.896-898 High-purity, sulfur-free ethylene is required to avoid poisoning of the catalyst. Ethylene concentration is about 20-30 vol% or 5 vol% when oxygen or air, respectively, is used as oxidants. The main byproducts are C02 and H20, and a very small amount of acetaldehyde is formed via isomerization of ethylene oxide. Selectivity to ethylene oxide is 65-75% (air process) or 70-80% (02 process).867 

Both associative [Eq. (9.167)] and dissociative [Eq. (9.168)] adsorptions of oxygen were found to occur on silver  

Dissociative adsorption occurring on four adjacent silver atoms (AgadJ) is responsible for nonselective oxidation to yield CO2. An optimum chlorine coverage of about 25% of surface silver atoms effectively blocks dissociative adsorption of oxygen by physical blocking ensuring increased selectivity. 

T empera- ture, °C Vapor a pres-sure, kPab Liquid Vaporiza-tion Den-sity T/l Heat. d capa-city, J/fe K)C Surface. e tension, mN/m (=dyn/cm) Viscosity, mPa-s (=cP) Thermal conduc-tivity, W/(m-K)f 

Temperature, K Entropy,a,b J/(mol-K)C Heat of r b d formation, kj / mof Free energy of formation, kj/mol Viscosity, pPa-sf Thermal conductivity/ W/(m-K) Heat capacity, J/(mol-K)C 

Ethylene oxide (freezing point -111.7°C, boiling point 10.4°C, flash point 18°C) is a colorless gas that condenses at low temperature into a mobile liquid. Ethylene oxide is miscible in all proportions with water or alcohol and is very soluble in ether. Ethylene oxide is slowly decomposed by water at standard conditions, converting into ethylene glycol (HOCH2CH2OH). 

For many years the manufacture of ethylene oxide was carried out by chlorohydrin formation followed by dehydrochlorination to the epoxide. 

Although the chlorohydrin route is still used to convert propylene to propylene oxide, a more efficient air epoxidation of ethylene in the presence of a silver catalyst is used and involves a direct oxidation method (Fig. 1). 

The yield is approximately 70 percent of the theoretical. For maximum yield, very careful temperature control is required, the yield dropping as the temperature climbs. Excessive oxidation to carbon dioxide and water can occur, so precise temperature control at 270 to 290°C and pressures of 120 to 300 psi with a 1-second contact time on the catalyst are necessary. Tubular reactors containing several thousand tubes (20 to 50 mm diameter) are used. Even though metallic silver is placed in the reactor, the actual catalyst is silver oxide under the conditions of the reaction. 

Ethylene oxide is used for manufacture of ethylene glycol, the latter being an antifreeze compound as well as a raw material for production of polyethylene terephthalate used in the manufacture of polyester fibers for preparation of surfactants for the manufacture of ethanolamines for production of ethylene glycols used in plasticizers, solvents, and lubricants and for making glycol ethers used as jet-fuel additives and solvents. 

Ethylene oxide is a very unstable compound that catches fire or explodes readily and must be handled with the greatest care. Nonetheless, it is an important industrial chemical and ranks nineteenth by volume among chemicals produced in the United States. Its primary use is in the manufacture of other organic compounds. 

Ethylene Oxide. Black atoms are carbon white atoms are hydrogen red atom is oxygen. White sticks show single bonds. 

The chlorhydrin process for making ethylene oxide has been replaced commercially by the direct oxidation of ethylene gas. Oxidation takes place at temperatures of 20o°C to ° (392°F to 572°F) over a silver catalyst. The formula for this reaction is 2CH2=CH2 + 02 — 2CH2CH20.The yield produced by direct oxidation is slightly less than that produced by the chlohydrin process, but the amount of chlorine wasted by the latter method outweighs the slight difference in efficiency of production. 

A ring with three atoms is top twenty-five chemicals 

Ethylene oxide also has a number of other important industrial uses, although the quantity used for such purposes is small compared to the uses mentioned above. For example, it is used as a rocket propellant because of its tendency to decompose easily with the release of large amounts of energy. It is also used as a sterilizing medium, particularly for the sterilization of surgical instruments and consumer products, such as spices and cosmetics. The compound is also used as a demulsifier in the petroleum industry. A demulsifier is a material that aids in the separation of the components of complex mixtures, like those handled in the processing of petroleum. Ethylene oxide is also used as a fumigant, which is a gas used to kill insects and other pests. 

Ethylene oxide is sold only in grades of 99.7 percent or higher purity. A typical specification is as follows  

Acidity, as acetic acid, weight percent maximum 

Ranges in specification values indicate a difference in the limits given by different producers. [2] 

Ethylene oxide was first prodrrced by BASF arrd Urrion Carbide in 1916 and 

This process used chlorine that could not easily be recovered, so attempts were made to develop a catalyst for direct oxidation The reaction is 

Modem processes operate reactors with the catalyst packed into 1- to 2-in tubes that are cooled by suitable heat transfer liquids  

TABLE 4.10. Ethylene Oxide Production by Air and Oxygen Processes.  

Reactor Tubular Several thousand tubes Tubular 

Preparation of ethylene glycol for antifreeze and synthetic textile fibers (60%), hospital sterilant (15%), surfactants (10%), other chemicals (10%). 

Suppliers BASF Corp., Dow, Huntsman, Eastman Chemical, Old World Trading, Equistar Chemicals, Union Carbide, and others. 

Ethylene glycol is made by reacting ethylene oxide with water  

Many laundry and dish detergents as well as shampoos are made from chemicals based on ethylene oxide. 

Vinyl chloride is used exclusively for the preparation of plastics, by homopolymerization to poly(vinyl chloride) (PVC) and by copolymerization with other vinyl (-CH2=CH-) compounds. 

Krasavage 3 Subchronic oral toxicity of ethylene glycol monobutyl ether in male rats. Fundam Appl Toxicol 6 349-355, 1986 

National Toxicology Program Toxicology and Carcinogenesis Studies of 2-Butoxyethanol in F344/N Rats and B6C3F1 Mice (Inhalation Studies) Technical Report Series 484, pp 

Nagano K, Nakayama E, Koyano M, et ah Testicular atrophy of mice induced by ethylene glycol mono alkyl ether. Jpn J Ind Health 21 29-35, 1979 

Chemical Manufacturers Association Glycol Fthers Program Panel Research Status Report, 5pp. Washington, DC, Chemical Manufacturers Association, April 22, 1985 

National Taxicology Program Ethylene Glycol Monobutyl Ether Reproduction and Eertility Assessment in CD-I Mice when Administered in Drinking Water. NTP-85-155. Final report, pp 1-240. National Institute of Environmental Health Sciences, May, 1985 

TC Shipping Name Ethylene Oxide TC Classification 2.1 TC Label FLAMMABLE GAS UN Number UN 1040 

Acidity, as acetic acid, weight percent maximum Chlorides, weight percent maximum 0.001-0.005 

LABORATORY CHEMICAL SAFETY SUMMARY ETHYLENE OXIDE  

Substance Ethylene oxide (1,2 Epoxyethane oxacyclopropane dimethylene oxide) CAS 75-21-8 

Physical Properties Colorless liquid or gas hp 10.7 °C,mp-111.3 °C Miscihle with water 

Major Hazards OSHA select carcinogen highly flammable severe irritant. 

Toxicity Ethylene oxide is a severe irritant to the eyes, skin, and respiratory tract and exhibits moderate acute toxicity by all routes of exposure. Symptoms of overexposure by inhalation may be delayed and can include nausea, vomiting, headache, drowsiness, and difficulty breathing. Ethylene oxide can cause serious bums to the skin, which may only appear after a delay of 1 to 5 hours. This substance may also be absorbed through the skin to cause the systemic effects listed above. Eye contact can result in severe bums. Ethylene oxide is not considered to have adequate warning properties. Ethylene oxide is listed by lARC in Group 2A ( probable human carcinogen ) and is classified as a select carcinogen under the criteria of the OSHA Laboratory Standard. There is some evidence from animal studies that ethylene oxide may be a developmental and reproductive toxin in both males and females. Exposure to this substance may lead to sensitization. 

Diethylene and triethylene glycol (DEG and TEG) are produced as byproducts of ethylene glycol. DEG and TEG are used in polyurethane and unsaturated polyester resins and in the drying of natural gas. DEG is also used in antifreeze and in the synthesis of morpholine, a solvent, corrosion inhibitor, antioxidant, and pharmaceutical intermediate. 

Exposure to epoxides can cause irritation of the skin, eyes, and respiratory tract. Low-molecular-weight epoxides are strong irritants and more toxic than those of higher molecular weight. Inhalation can produce pulmonary edema and affect the lungs, central nervous system, and liver. Occupational exposure to ethylene oxide may cause axonal neuropathy 

Many epoxy compounds have been found to cause cancer in animals. 

Lower epoxides are highly flammable. They polymerize readily in the presence of strong acids and active catalysts. The reaction generates heat and pressure, which may rupture closed containers. Contact with anhydrous metal halides, strong bases, and readily oxidizable substances should therefore be avoided. 

Ethylene oxide and other hazardous epoxides characterized by the presence of three-membered strained oxirane ring structures are discussed individually in the following sections. Miscellaneous epoxy compounds with low toxicity and flammability and low commercial applications are discussed in Table 16.1. 

A Comprehensive Guide to the Hazardous Properties of Chemical Substances, by Pradyot Patnaik Copyright 2007 John Wiley Sons, Inc. 

Chemical sterilization is not routinely used in microbiology laboratories. In packaging of sterile Petri plates and other plastic disposable supplies which cannot be heat sterilized, the gas ethylene oxide is used. However, given its toxic and explosive properties, ethylene oxide is not widely used in routine laboratory work. 

In winery laboratories, sterilization of reactivation or expansion volumes of grape juice by heating is sometimes an issue of concern due to the development of cooked characters that may be transferred to the wine. In these cases, we have effectively utilized dimethyldicarbonate (DMDC) sold by Scott Laboratories (Petuluma, CA) under the trade name Vel-corin. At levels of 250-400 mg/L, this cold sterilant accomplishes the goal in several hours. Residual DMDC then breaks down to methanol and carbon dioxide (Porter and Ough, 1982). Unlike a gas (i.e., ethylene oxide) DMDC, a liquid, is only active in the liquid phase. Thus, the culture vessel and its closure must be sterilized (by heat or multiple ethanol rinses) prior 

This compound also deserves attention as a monergol. Its physical constants are boiling point 11°C, freezing point — 112°G, density 0.90. It decomposes exothermically according to the theoretical equation  

In point of fact the reaction is more complicated and proceeds according to the equation  

Pressure in chamber atm Composition of products (%) Temperature of explosion °C Specific impulse sec 

Ethylene oxide has the advantage of being safe to handle since it is not strictly an explosive. 

8 [ C ]Benzene and the Synthesis of Ring-Laheled Aromatic Compounds 

As previously mentioned, [U- C]benzene can be conveniently prepared in almost 90% yield by KC-Perlcatalysator-catalyzed trimerization of [ C ]acetylene . Also known as KC-Perkator, the catalyst is a family of silica-alumina matrices activated with C12O 

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An example of a parallel reaction system occurs in the production of ethylene oxide ... 

An example of mixed parallel and series reactions is the production of ethanolamines by reaction between ethylene oxide and ammonia ... 

Here the ethylene oxide undergoes parallel reactions, whereas the monoethanolamine undergoes a series reaction to diethanolamine and triethanolamine. 

The secondary reactions are parallel with respect to ethylene oxide but series with respect to monoethanolamine. Monoethanolamine is more valuable than both the di- and triethanolamine. As a first step in the flowsheet synthesis, make an initial choice of reactor which will maximize the production of monoethanolamine relative to di- and triethanolamine. 

An excess of ammonia in the reactor decreases the concentrations of monoetha-nolamine, diethanolamine, and ethylene oxide and decreases the rates of reaction for both secondary reactions. 

The use of an excess of ammonia is home out in practice. A mole ratio of ammonia to ethylene oxide of 10 1 3delds 75 percent monoethanolamine, 21 percent diethanolamine, and 4 percent triethanolamine. Using equimolar proportions under the same reaction conditions, the respective proportions become 12, 23, and 65 percent. 

Can the useful material lost in the purge streams be reduced by additional reaction If the purge stream contains significant quantities of reactants, then placing a reactor and additional separation on the purge can sometimes be justified. This technique is used in some designs of ethylene oxide processes. 

Simplest examples are prepared by the cyclic oligomerization of ethylene oxide. They act as complexing agents which solubilize alkali metal ions in non-polar solvents, complex alkaline earth cations, transition metal cations and ammonium cations, e.g. 12—crown —4 is specific for the lithium cation. Used in phase-transfer chemistry. ... 

C HioOj, (H0CH2CH2)20. A colourless and almost odourless liquid b.p. 244 C. Readily absorbs moisture from the atmosphere. It is obtained as a by-product in the manufacture of ethylene glycol by the hydra-lion of ethylene oxide. Manufactured by heat-... 

HOCHj CHjOH. Colourless, odourless, rather viscous hygroscopic liquid having a sweet taste, b.p. 197 C. Manufactured from ethylene chlorohydrin and NaHC03 solution, or by the hydration of ethylene oxide with dilute sulphuric acid or water under pressure at 195°C. Used in anti-freezes and coolants for engines (50 %) and in manufacture of polyester fibres (e.g. Terylene) and in the manufacture of various esters used as plasticizers. U.S. production 1979 1 900 000 tonnes. 

CH3CH1CH2CH2OCH2CH2OH. Colourless liquid with a pleasant odour b.p. 17rC. Manufactured by heating ethylene oxide with 1-butanol in the presence of nickel sulphate as a catalyst. Used as a solvent in brushing lacquers. 

Trimethylamine, CjH N, (CH3J3N. Colourless liquid with a strong fishy odour, miscible with water, m.p. — I24 C, b.p. 3-5°C. It occurs naturally in plants, herring brine, bone oil and urine. It reacts with hydrogen peroxide to give trimethylamine oxide and with ethylene oxide to give choline its commercial importance stems chiefly from this latter reaction. 

Me3CCH2CMe2C H40H. M.p. 8l-83"C, b.p. 286-288°C. Made by alkylation of phenol. Forms oil-soluble resins with methanal (salts used as oil additives) and surfactants (with ethylene oxide). 

Prepared by epoxidation of styrene with per-oxyelhanoic acid. Reactions are similar to those of aliphatic epoxides (s e, e.g. ethylene oxide). Reacts with alcohols to give mono-ethers, e g. PhCH(0Me)CH20H. Phenols give resins. 

Fig. XI-7. Volume fraction profile of 280,000-molecular-weight poly(ethylene oxide) adsorbed onto deuterated polystyrene latex at a surface density of 1.21 mg/m and suspended in D2O, from Ref. 70.

Kuhl T Let al 1994 Modulation of interaction forces between bilayers exposing short-chained ethylene oxide headgroups Biophys. J. 66 1479-88... 

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