Alcohols 1.2- ethanediol

Comments Enthalpies of mixing for benzyl alcohol + 1,2-ethanediol, + diethylene glycol or + triethylene glycol are given in the original source. 

All the investigations cited so far have been in aqueous solution medium dependence of dissociation rate constants in binary aqueous solvents (cosolvents methanol, r-butyl alcohol, 1,2-ethanediol, 1,2,3-propanetriol, and sucrose) has been reported for the 4-cyanopyridine and 4,4 -bipyridyl penta-cyanoferrates(II). For water-rich media (IQi lD < 16.5), plots of logarithms of rate constants against mole fraction organic component are linear, against 1/D almost linear. Slopes differ greatly between cosolvents, but results can be correlated quite satisfactorily with a three-parameter equation incorporating acidity and basicity parameters and the excess function... 

The last variation we should discuss is about the use of solvent. Ever-bitching about the rarity and price of chemicals, the bees have thrust their anger at the DMF used in this method. TDK sent Strike an article that gives some credence to this [16]. In it the alcohols methanol, ethanol, 1-propanol, ethanediol and others were used in place of DMF with beautifully high yields. Below is the sample experimental from the article Oust picture using safrole or allylbenzene in place of the 1-hexene) ... 

HO2 + Silica TiOz + Silica 1,2-Ethanediol Various alcohols and adds Methacrylic 51.70) 72)... 

C (associated with various transition metals) Si Si02 (associated with Ti02) Aluminium silicate Silica gel as support or alone 1,2-Ethanediol Various alcohols and acids Various alcohols and acids Various alcohols and acids Terephthalic 129,130) 51,70) 124) 36,131, 134-137, 175)... 

Kemkes256 assumes that the overall order relative to the esterification of terephthalic acid by 1,2-ethanediol in oligo(l,2-ethanediyl terephthalate) is two no mechanism has however been suggested. Mares257 considers that during the esterification of terephthalic acid with 1,2-ethanediol, two parallel kinetic paths take place, one corresponding to a reaction catalyzed by non-dissociated add and the other to a non-catalyzed process. In fact, Mares257 is reserved about the existence of protonic catalysis. Some other orders were found for the system terephthalic atid/l,2-ethanediol 0 (overall)318 2 (add) andO (alcohol)203 1 (add) and 1 (alcohol)181 1 (add)194 . These contradictory results could be partly due to the low solubility of terephthalic acid in 1,2-ethanediol. 

Several results were reported by Russian authors. They are completely different from those reported above. Sorokin14 found an overall reaction order of 2 for the system heptanoic acid/l,2-ethanediol/diphenyl oxide. Bolotina16 studied the reaction of 2-ethylhexyl hydrogenphthalate with 2-ethylhexanol in the corresponding diester and found an order of 1 with respect to acid and of 2 with respect to alcohol. 

Recently, Lin17 270 271 found a 3rd-order for the reaction of sucdnic and adipic adds with 1 -ethanediol in the presence of an excess of a diol. Surprisingly, he found orders 1 with respect to add and 2 with respect to alcohol. This was explained by the fact that acid... 

From the results of Malek et al.49,561 m 205,206,211) it may be concluded that the various metal derivatives used in esterifications exhibit many common catalytic characteristics. Thus, these authors190 established relationships concerning the free energies of esterification of thirteen ortho-, meta- and para-substituted benzoic adds by 1,2-ethanediol. They obtained Hammett parameters which do not differ greatly from those found for the add-catalyzed esterifications of the same adds with various alcohols. They concluded... 

Fig. 12.4. Successive models of the transition state for Sharpless epoxidation. (a) the hexacoordinate Ti core with uncoordinated alkene (b) Ti with methylhydroperoxide, allyl alcohol, and ethanediol as ligands (c) monomeric catalytic center incorporating t-butylhydroperoxide as oxidant (d) monomeric catalytic center with formyl groups added (e) dimeric transition state with chiral tartrate model (E = CH = O). Reproduced from J. Am. Chem. Soc., 117, 11327 (1995), by permission of the American Chemical Society. 

Synonyms 1,2 Dihydroxyethane 1,2-ethanediol ethylene alcohol ethylene dihydrate... 

Instead of two molecules of alcohols, a diol is often used. This produces cyclic acetals. 1,2-ethanediol (ethylene glycol) is usually the diol of choice, and the products are called ethylene acetals. 

GLYCOL. A dihydric alcohol (i.e.. a compound conlaining two alcoholic hydroxy] groups). The chemical properties are represented by those of the simplest members of the class, ethylene glycol, 1,2-ethanediol. CH-OH CHjOH. which is a colorless, viscous liquid, of sweetish taste. Odorless, boiling point I97°C. miscible in all proportions with water or alcohol, slightly soluble in ether. Like ethyl alcohol, ethylene glycol is often called by the class name. 

Diaryl ketones do not undergo photodissociation in the same way as alkyl ketones, probably because cleavage to phenyl and other aryl radicals is unfavorable (Table 4-6). Nevertheless, aromatic ketones are photochemically reactive in the presence of compounds that can donate a hydrogen atom, with the result that the carbonyl group is reduced. Indeed, one of the classic photochemical reactions of organic chemistry is the formation of 1,1,2,2-tetraphenyl-1,2-ethanediol (3, benzopinacol) by the action of light on a solution of diphenyl-methanone (2, benzophenone) in isopropyl alcohol. The yield is quantitative. 

Polymers usually are prepared by two different types of polymerization reactions — addition and condensation. In addition polymerization all of the atoms of the monomer molecules become part of the polymer in condensation polymerization some of the atoms of the monomer are split off in the reaction as water, alcohol, ammonia, or carbon dioxide, and so on. Some polymers can be formed either by addition or condensation reactions. An example is polyethylene glycol, which, in principle, can form either by dehydration of 1,2-ethanediol (ethylene glycol), which is condensation, or by addition polymerization of oxacyclopropane (ethylene oxide) 1... 

According to protonation thermochemistry of simple a,(0-diols (1,2-ethanediol, 1,3-propanediol, 1,4-butanediol), the diols show enhanced proton affinities in the gas phase compared with primary alcohols attributed to the formation of a strong intramolecular hydrogen bond.59 60... 

For two-carbon alcohols, LUMO decreases as the number of chlorines increases. As LUMO decreases, the ability of a compound to undergo reduction increases therefore, an increase in chlorine increases the reactivity of the molecule. The dataset contains 2,2,2-trichloro-l,l-ethanediol 2,2,2-trichloroethanol 2,2-dichloroethanol and 2-chloroethanol. LUMO represents 99.85% of the variance in the linear regression equation. The probability of getting a correlation of -0.9992 for a sample size of four is less than 1%. 

Synonym 1,2-ethanediol Formula HOCH2CH2OH MW 62.07 CAS [107-21-1] used as antifreeze in cooling and heating systems and in hydraulic brake fluids colorless liquid sweet taste hygroscopic density 1.11 g/mL boils at 197.5°C freezes at -13°C highly soluble in water, lower alcohols, acetone, and pyridine toxic. 

Some solvents are reluctant to crystallize before turning into a glass, including allyl alcohol (2-propen-l-ol), ethylene glycol (1,2-ethanediol), and hexylene glycol (2-methyl-pentane-2,4-diol). Some common solvents may be liquid below their freezing points if they contain impurities, in particular small amounts of water. Thus, /-butyl alcohol (2-methyl-2-propanol), acetic acid, and phenol can appear liquid at or below ambient temperatures (i.e., < Tm) due to this cause. 

Aldehydes and ketones are usually protected by converting them to acetals by reaction with an alcohol in the presence of acid (see Section 18.9). Although many different alcohols could be used, ethylene glycol (1,2-ethanediol) or 1,3-propanediol is most often... 

Ethanediol could best be removed by extracting 250 g of the alcohol in 750 ml of benzene with 5-ml portions of water, allowing 10 min for separation of the phases. The volumes of the aqueous extracts are accurately measured, the increase in volume calculated and the extraction continued until the increase in volume becomes constant. 

The second method for liquefaction makes use of solvolysis during the process [8,11]. By using conditions which allow phenolysis of part of the lignin, especially in the presence of an appropriate catalyst, the liquefaction of chemically modified wood into phenols could be accomplished under milder conditions (at 80 C for 30-150 min). Allylated wood, methylated wood, ethylated wood, hydroxyethylated wood, acetylated wood, and others have been found to dissolve in polyhydric alcohols such as 1,6-hexanediol, 1,4-butanediol, 1,2-ethanediol, 1,2,3-propanetriol (glycerin), and bisphenol A using the liquefaction conditions just described. Each of them caused partial alcoholysis of lignin macromolecules [4]. 

Many polyhydroxyl (more than one —OH group) alcohols are known, the most important being 1,2-ethanediol (ethylene glycol),... 

The oxidation of glycols occurred preferentially at the secondary alcohol group. Thus, propene glycol and 2-phenyl-l,2-ethanediol afforded hydroxyacetone and P-hydroxyacetophenone, respectively, as the major product [115]. Ethene glycol... 

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