Ethylene oxide number

More important for the application of nonionics in practice is knowledge of the relationship between the stabilising effect and the average ethylene oxide number in the molecule. The surfactant concentration c, necessary to increase the shelf-life of a standard emulsion is taken as a measure of the stabilising effect. Fig. 1.16 shows such a relationship for ethoxylated dodecanol (Muller Kretzschmar 1982). The ratio of the hydrophilic and hydrophobic parts in the molecule has a direct bearing on the concentration needed to stabilise the toluene-in-water system. The ethylene oxide adducts possesses particularly high variability and are readily available. 

The nonionic surfactant characteristic is split into its ethylene oxide number tEON). i.e.. the average number of ethylene oxide groups per molecule, and the hydrophobe contribution OC. Only scarce data are available for a, which has a value near 6,6 and 6.1. respectively, for the branched nonyl and octyl phenol... 

As an example of the different phases of surfactants. Figure 3.27 shows the phase diagram of a pure nonionic surfactant of the alkyl polyglycol ether type (20). In particular, the phase behaviour of nonionic surfactants with a low degree of ethoxylation is very complex. As the lower consolute boundary is shifted to lower temperatures with a decreasing EO (ethylene oxide) number of the molecule, an overlapping of this boundary... 

Among commercial nonionic surfactants, those made from fatty alcohols with ethylene oxide are the most commonly used. Ethoxylation offers the production of a wide range of nonionic surfactants as the hydrophobic part, and the ethylene oxide number can be easily adjusted according to the desired properties. The chemical reaction to convert a fatty alcohol into a nonionic ethoxylated surfactant uses ethylene oxide under pressure (typically 2-8 bars) and heat (typically 120-200°C). Actually, fatty alcohols have a hydroxyl group that can react further with ethylene oxide providing polyoxyethylene compounds with a range of molecular weights. 

This effect of temperature has been recognized first on nonionic surfactant systems, and the temperature is still the choice variable to study nonionic surfactant systems phase behavior [51,56-58]. According to the Winsor approach, it is clear that the temperature is likely to change not only Acw but all other interactions as well, a situation that does not simplify the interpretation of experimental data. Moreover, the temperature range that can be experimentally handled without complication is not very wide, because it matches the liquid state of water. This is why the electrolyte concentration (salinity) and ethylene oxide number (EON) have been often preferred by experimentalists as scanning variables for ionic and nonionic systems, respectively, as their effect is easier to predict and interpret. 

In each case the ring is numbered starting at the oxygen The lUPAC rules also permit oxirane (without substituents) to be called ethylene oxide Tetrahydrofuran and tetrahy dropyran are acceptable synonyms for oxolane and oxane respectively... 

Although catalytic hydration of ethylene oxide to maximize ethylene glycol production has been studied by a number of companies with numerous materials patented as catalysts, there has been no reported industrial manufacture of ethylene glycol via catalytic ethylene oxide hydrolysis. Studied catalysts include sulfonic acids, carboxyUc acids and salts, cation-exchange resins, acidic zeoHtes, haUdes, anion-exchange resins, metals, metal oxides, and metal salts (21—26). Carbon dioxide as a cocatalyst with many of the same materials has also received extensive study. 

Polymer Blends. The miscibility of poly(ethylene oxide) with a number of other polymers has been studied, eg, with poly (methyl methacrylate) (18—23), poly(vinyl acetate) (24—27), polyvinylpyrroHdinone (28), nylon (29), poly(vinyl alcohol) (30), phenoxy resins (31), cellulose (32), cellulose ethers (33), poly(vinyl chloride) (34), poly(lactic acid) (35), poly(hydroxybutyrate) (36), poly(acryhc acid) (37), polypropylene (38), and polyethylene (39). 

The reaction is exothermic reaction rates decrease with increased carbon number of the oxide (ethylene oxide > propylene oxide > butylene oxide). The ammonia—oxide ratio determines the product spht among the mono-, di-, and trialkanolamines. A high ammonia to oxide ratio favors monoproduction a low ammonia to oxide ratio favors trialkanolamine production. Mono- and dialkanolamines can also be recycled to the reactor to increase di-or trialkanolamine production. Mono- and dialkanolamines can also be converted to trialkanolamines by reaction of the mono- and di- with oxide in batch reactors. In all cases, the reaction is mn with excess ammonia to prevent unreacted oxide from leaving the reactor. 

The number of ethylene oxide units added to the phenoxide depends on the apphcation of the ethoxylate. This chemistry is closely related to the reaction between an alkylphenol and epichlorohyddn which is used ia epoxy resias (qv). 

The critical parameters of ethylene oxide steriliza tion are temperature, time, gas concentration, and relative humidity. The critical role of humidity has been demonstrated by a number of studies (11,18,19). Temperature, time, and gas concentration requirements are dependent not only on the bioburden, but also on the type of hardware and gas mixture used. If cycle development is not possible, as in the case of hospital steriliza tion, the manufacturer s recommendations should be followed. 

Reaction of olefin oxides (epoxides) to produce poly(oxyalkylene) ether derivatives is the etherification of polyols of greatest commercial importance. Epoxides used include ethylene oxide, propylene oxide, and epichl orohydrin. The products of oxyalkylation have the same number of hydroxyl groups per mole as the starting polyol. Examples include the poly(oxypropylene) ethers of sorbitol (130) and lactitol (131), usually formed in the presence of an alkaline catalyst such as potassium hydroxide. Reaction of epichl orohydrin and isosorbide leads to the bisglycidyl ether (132). A polysubstituted carboxyethyl ether of mannitol has been obtained by the interaction of mannitol with acrylonitrile followed by hydrolysis of the intermediate cyanoethyl ether (133). 

Number of ethylene oxide groups in esterified polyoxyethylene (POE). See Table 1. 

A second class of important electrolytes for rechargeable lithium batteries are soHd electrolytes. Of particular importance is the class known as soHd polymer electrolytes (SPEs). SPEs are polymers capable of forming complexes with lithium salts to yield ionic conductivity. The best known of the SPEs are the lithium salt complexes of poly(ethylene oxide) [25322-68-3] (PEO), —(CH2CH20) —, and poly(propylene oxide) [25322-69-4] (PPO) (11—13). Whereas a number of experimental battery systems have been constmcted using PEO and PPO electrolytes, these systems have not exhibited suitable conductivities at or near room temperature. Advances in the 1980s included a new class of SPE based on polyphosphazene complexes suggesting that room temperature SPE batteries may be achievable (14,15). 

These products are characterized in terms of moles of substitution (MS) rather than DS. MS is used because the reaction of an ethylene oxide or propylene oxide molecule with ceUulose leads to the formation of a new hydroxyl group with which another alkylene oxide molecule can react to form an oligomeric side chain. Therefore, theoreticaUy, there is no limit to the moles of substituent that can be added to each D-glucopyranosyl unit. MS denotes the average number of moles of alkylene oxide that has reacted per D-glucopyranosyl unit. Because starch is usuaUy derivatized to a considerably lesser degree than is ceUulose, formation of substituent poly(alkylene oxide) chains does not usuaUy occur when starch is hydroxyalkylated and DS = MS. 

Elastomer ECH, % Chlorine, % Ethylene oxide, % CAS Registry Number Specific gravity ml T,°C... 

The reactions are highly exothermic. Under Uquid-phase conditions at about 200°C, the overall heat of reaction is —83.7 to —104.6 kJ/mol (—20 to —25 kcal/mol) ethylene oxide reacting (324). The opening of the oxide ring is considered to occur by an ionic mechanism with a nucleophilic attack on one of the epoxide carbon atoms (325). Both acidic and basic catalysts accelerate the reactions, as does elevated temperature. The reaction kinetics and product distribution have been studied by a number of workers (326,327). 

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