Ethylene oxide by water

FIGURE 16 6 The mecha nism for the acid catalyzed nucleophilic ring opening of ethylene oxide by water... 

Following the absorption of ethylene oxide by water from a process stream, a 600-Ibmol/h water stream (prior to discharge) is steam-stripped of the ethylene oxide as part of the regeneration step. For a feed ethylene oxide concentration of 0.5 mol %, determine the actual amount of steam required for stripping ethylene oxide to a concentration of 0.03 mol %. 

Analysis for Poly(Ethylene Oxide). Another special analytical method takes advantage of the fact that poly(ethylene oxide) forms a water-insoluble association compound with poly(acryhc acid). This reaction can be used in the analysis of the concentration of poly(ethylene oxide) in a dilute aqueous solution. Ereshly prepared poly(acryhc acid) is added to a solution of unknown poly(ethylene oxide) concentration. A precipitate forms, and its concentration can be measured turbidimetricaHy. Using appropriate caUbration standards, the precipitate concentration can then be converted to concentration of poly(ethylene oxide). The optimum resin concentration in the unknown sample is 0.2—0.4 ppm. Therefore, it is necessary to dilute more concentrated solutions to this range before analysis (97). Low concentrations of poly(ethylene oxide) in water may also be determined by viscometry (98) or by complexation with KI and then titration with Na2S202 (99). 

With Water. Wurtz was the first to obtain ethylene glycol by heating ethylene oxide and water in a sealed tube (1). Later, it was noted that by-products, namely diethjlene and triethylene glycol, were also formed in this reaction (50). This was the first synthesis of polymeric compounds of well-defined stmcture. Hydration is slow at ambient temperatures and neutral conditions, but is much faster with either acid or base catalysis (Table 8). The type of anion in the catalyzing acid is relatively unimportant (58) (see Glycols). 

Ethylene Oxide Purification. The main impurities ia ethylene oxide are water, carbon dioxide, and both acetaldehyde and formaldehyde. Water and carbon dioxide are removed by distillation ia columns containing only rectifying or stripping sections. Aldehydes are separated from ethylene... 

Ethylene glycol is made by reacting ethylene oxide with water ... 

Ethylene is to be converted by catalytic air oxidation to ethylene oxide. The air and ethylene are mixed in the ratio 10 1 by volume. This mixture is combined with a recycle stream and the two streams are fed to the reactor. Of the ethylene entering the reactor, 40% is converted to ethylene oxide, 20% is converted to carbon dioxide and water, and the rest does not react. The exit gases from the reactor are treated to remove substantially all of the ethylene oxide and water, and the residue recycled. Purging of the recycle is required to avoid accumulation of carbon dioxide and hence maintain a constant feed to the reactor. Calculate the ratio of purge to recycle if not more than 8% of the ethylene fed is lost in the purge. What will be the composition of the corresponding reactor feed gas ... 

Automobile Antifreeze. Ethylene glycol and diethylene glycol are used as automobile antifreeze, and are produced by the reactions of ethylene oxide with water, as follows ... 

Ethylene was reacted with chlorine water, or with a mixture of hydrated lime and chlorine. In the latter case the Ca(OCl)2 formed decomposes to yield HOC1. The aqueous opening of the intermediate chloronium ion leads to the formation of the product. Ethylene chlorohydrin then was cyclized to ethylene oxide by addition of calcium hydroxide. 

It is very interesting the adsorption behavior of poly (ethylene oxide) from water solution to the air - water interface. This adsorption was considerably enhanced by a hydrophobic group placed at ends of the molecules. 

Derivatives from pure ethylene oxide are water soluble and result in silicon polyols with water solubility or dispersibility. Propylene oxide and even more butylene oxide allow for more compatibility with organic media, e.g. butylene oxide gives compatibility with organic oils. Depending upon the demanded balance of hydrophilicity/hydrophobicity, different proportions and order of addition of the alkoxide can be used. In certain instances blocking of the terminal hydroxyl group maybe required, e.g. by reaction with methyl or, less commonly, benzyl chloride. 

Polyethylene Glycol Also known as macrogol, PEG is synthesized by condensation of ethylene oxide and water under suitable reaction conditions. Based on the... 

DOT CLASSIFICATION 5.1 Label Oxidizer SAFETY PROFILE Moderately toxic by intraperitoneal route. Severe skin and eye irritant. A powerful oxidizer which has caused many explosions in industry. Potentially explosive reactions with alkenes (above 220°C), ammonia, arjl hydrazine + ether, dimethyl sulfoxide + heat, ethylene oxide, fluorobutane + water, organic materials, phosphorus, trimethyl phosphate. Reacts to form explosive products with ethanol (forms ethyl perchlorate), cellulose + dinitrogen tetraoxide + oxygen (forms cellulose nitrate). Avoid contact with mineral acids, butyl fluorides, hydrocarbons. A drying agent. When heated to decomposition it emits toxic fumes of MgO and Cr. See also MAGNESIUM COMPOUNDS and PERCHLORATES. 

Ethoxylated tertiary amines can be produced by the reaction of primary or secondary amines with ethylene oxide. The water solubility of this amine increases with the increasing degree of ethoxylation (33). 

Polyethylene glycols are condensation polymers formed by the reaction of ethylene oxide and water under pressure in the presence of a catalyst. 

Problem 32.10 Draw the structure of the product expected from the killing of living polystyrene by each of the following reagents (a) water (b) carbon dioxide, then water (c) a small amount of ethylene oxide, then water (d) a large amount of ethylene oxide, then water. 

Some diols can be converted into cyclic ethers by tieatment with a strong acid catalyst. Use SpartanView to find the energies of the reactants and products of two such reactions 1,2-ethanediol —> ethylene oxide 4 water, and 1,4-butanediol —> tetrahydrofuran -( water. Which reaction has a more favorable and which has a more favorable AS Explain. 

Yu et al.180 have synthesized cyclic diblock copolymers of ethylene oxide and propylene oxide. They polymerized sequentially propylene oxide and ethylene oxide by using the difunctional initiator (I) shown in Scheme 89. The cyclization reaction of the a,a>-hydroxyl-ended diblock macromolecules was carried out under Williamson conditions. A solution of the triblock precursor in a mixture of dichloromethane and hexane 65 35 (v/v) was added to a stirred suspension of powdered KOH (85% w/v) in the same dichloromethane/hexane mixture (Scheme 89). After separation and evaporation of the organic phase, the cyclic diblocks were isolated by fractional precipitation. The dilute solution properties of the cyclics and the corresponding linear triblock and diblock copolymers with the same composition and total molecular weight were compared. By examining the micellar behavior in water they found that the aggregation numbers were on the order Nj < Nc < No, where N Nq, and No, are the aggregation numbers of the triblocks, cyclic, and diblocks, respectively. 

---