Ethylene glycol hydroxyl groups

Polyhydric alcohols are compounds containing two or more hydroxyl groups in the molecule. The two most important are ethylene glycol HOCHjCHjOH (a dihydric alcohol) and glycerol HOCHjCH(OH)CH. OH (a trihydric alcohol). Ethylene glycol may be obtained by the hydrolysis of ethylene dibromide or ethylene dichloride with dilute aqueous sodium hydroxide or sodium carbonate solution ... 

Diols that bear two hydroxyl groups m a 1 2 or 1 3 relationship to each other yield cyclic acetals on reaction with either aldehydes or ketones The five membered cyclic acetals derived from ethylene glycol (12 ethanediol) are the most commonly encoun tered examples Often the position of equilibrium is made more favorable by removing the water formed m the reaction by azeotropic distillation with benzene or toluene... 

Diols, such as ethylene glycol, are usually not added during the alcoholysis step because their monoesters have only one remaining hydroxyl group, and would function as chain stoppers, thus severely limiting their utihty in the stmcture design of the resin molecules. 

Amino Alcohols. Reaction of chloroformate is much more rapid at the amino group than at the hydroxyl group (4—8). Thus the hydroxy carbamates, which can be cyclized with base to yield 2-oxazoHdones, can be selectively prepared (29). Nonionic detergents may be prepared from poly[(ethylene glycol) bis(chloroformates)] and long-chain tertiary amino alcohols (30). 

Surfactants and Dispersants. Castor od can be transformed from an od- to a water-soluble surfactant, depending on the moles of ethylene oxide added to its hydroxyl group. A 40 mole ethylene oxide adduct of castor od, known as PEG-40 castor od, is a surfactant that has cosolvent properties and is utilized as a fragrance solubilizer (118). Glycol hydroxystearate emulsifiers are formulated into shampoos to impart finer peadescence and give better stabdity than gylcol stearates (118) (see Hair preparation). 

Both polyethers and polyesters may be used as polyols. For example, Du Pont use polytetrahydrofuran for Lycra whilst US Rubber originally used a polyester of molecular mass of about 2000 obtained by condensing adipic acid with a mixture of ethylene and propylene glycols. A polyether-based mixture was used for Vyrene 2 introduced in 1967. All the polyols have terminal hydroxyl groups. 

Rosins are commonly combined with alcohols with more than one hydroxyl group such as ethylene glycol and diethylene glycol (two hydroxyl groups). 

A 17a-hydroxyl group reduces the reactivity of the 20-ketone but direct ketalization with ethylene glycol is not impeded, Ketalization can also be effected in the presence of 17a- and/or 21-hydroxy substituents. Thus the 3,20-biscycloethyleneketal (88) is obtained from (87) in high yield by the direct procedure, or better by distillation under vacuum without a diluent. A bromine atom at C-17 and a 21-acetoxy group even in the absence of a 17a-hydroxyl group strongly hinder ketalization at C-20. ... 

Epichlorhydrin.—It is a noteworthy fact that althoug-h hydiochloric acid can leplace hydroxyl by chlorine in the case of the monohydric alcohols, the number of hydroxyl groups which are substituted in the case of polyhydric alcohols is strictly limited. Like glyceiol, ethylene glycol gives a chlorhydrin, CIi..OH.CILOII 1- IICl CHnOH.CILCl -1- ILO. 

Apart from poly(ethylene glycol), other hydroxyl-terminated polymers and low-molecular weight compounds were condensed with ACPC. An interesting example is the reaction of ACPC with preformed poly(bu-tadiene) possessing terminal OH groups [26]. The reaction was carried out in chloroform solution and (CH3CH2)3N was used as a catalyst. MAIs based on butadiene thus obtained were used for the thermally induced block copolymerization with styrene [26] and dimethyl itaconate [27]. 

Sometimes a small amount of alcohol with one to three hydroxyl groups, like ethanol, isopropyl alcohol, n-butanol, or ethylene glycol, is added [33]. 

Ethylene glycol, or 1,2-ethanediol, HOCH2CH2OH (2), is an example of a diol, which is a compound with two hydroxyl groups. Ethylene glycol is used as a component of antifreeze mixtures and in the manufacture of some synthetic fibers. 

A new ethylene glycol molecule can condense with the carboxyl group on one end of the product, and another terephthalic acid molecule can condense with the hydroxyl group on the other end. As a result, the polymer grows at both ends and becomes... 

Vicinal hydroxyl groups, as in an ethylene glycol unit, have conformational attributes that can be described by using acyclic orientational notation... 

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