Ethylene glycol acetate

Ethanol-water Minimum-hoiling azeotrope Ethylene glycol, acetate salts for salt process Alternative to azeotropic distillation, pressure swing distillation... 

Ethylene and propylene, the simplest alkenes, are the two most important organic chemicals produced industrially. Approximately 26 million tons of ethylene and 17 million tons of propylene are produced each year in the United States for use in the synthesis of polyethylene, polypropylene, ethylene glycol, acetic acid, acetaldehyde, and a host of other substances (Figure 6.11. 

Ethylene glycol, acetals from, 719 manufacture of, 234 uses of, 234... 

The use of 2-vinyldioxolane, the ethylene glycol acetal of acrolein, as a dienophile illustrates application of the masked functionality concept in a different way. The acetal itself would not be expected to be a reactive dienophile, but in the presence of a catalytic amount of acid the acetal is in equilibrium with the electrophilic oxonium ion. 

Similar reactivity is realized with 2-acetylthiophene using triethylsilane with aluminum chloride.259 Treatment of the ethylene glycol acetal of 2-thiophenecar-baldehyde with Et3SiH/TFA results in reduction of the ring and oxidation of the side chain to the silylated carboxylic acid (Eq. 119),260 whereas similar treatment of 2-thiophenecarbaldehyde gives 2-methyltetrahydrothiophene and 2-... 

Diphenylmethylsilyl-protected hemiacetals are reduced upon treatment with Ph2SiH2/Mn(CO)3Ac.295 Et SiH/TiCB reduces tert-butyldimethylsilyl ketals.306 The combination of TBSH/Sn(OTf)2 and a silyl ether converts ethylene glycol acetals and ketals into ethers (Eq. 309).501... 

Table 1 Pre-selected properties for the design of alternatives for Ethylene Glycol Acetate...

If the additional substance stays in the residue, the process is called extractive distillation of aqueous solutions. The separations of various alcohols, ethylene glycol, acetic acid, acetone, and nitric acid from water is an example in which extractive distillation has been used or proposed. References (108) and (126) describe processes. 

The superfluous bromine is then removed by reduction with zinc in acetic acid (26-1). The 20 ketone is next protected against the strongly reducing conditions in the subsequent step by conversion to the ethylene glycol acetal (26-2). Birch reduction with lithium in liquid ammonia in the presence of ethanol proceeds as usual to the dihydrobenzene (26-3). Treatment of this last product with mineral acid serves to hydrolyze both the enol ether at the 3 position and the acetal at the... 

The possible intermediacy of formaldehyde in CO hydrogenation has been addressed above with regard to the cobalt catalytic system. Fahey has observed a small amount of 1,3-dioxolane (the ethylene glycol acetal of formaldehyde) as a product of the rhodium system (43). Thus, there is evidence that formaldehyde or a complexed form of this molecule could be an intermediate in the CO reduction process by this system. Rhodium catalysts are indeed found to be useful for the hydroformylation of formaldehyde to glycolaldehyde (159-161) methanol is a by-product in these reactions. 

Reactions conducted in molten quaternary phosphonium salts require no other solvent (199). This material serves as both promoter and reaction medium. Care must be exercised in choosing the salt in such a reaction, since any decomposition could lead to products such as trialkylphosphines and alkyl halides which are expected to be deleterious to catalyst performance. Tetrabutylphosphonium bromide is reported to provide a stable catalyst medium which can be recycled (199, 200), but other related salts show evidence of thermal decomposition during catalytic reactions. Experiments in tetrabutylphosphonium acetate, for example, are found to produce large amounts of methyl and ethylene glycol acetate esters (199). 

Reaction of 1,2-dimethylcyclohexene with the ethylene glycol acetal of acrolein in methylene chloride in the presence of 25 mol % of BF3.0Et2 at -78 to -10°C for 2 hours gives a 70% yield of the cycloadduct 1 in a formal 2k + 2% intermolecular cycloaddition. All of the evidence for this and related reactions, however, indicates a stepwise mechanism for the formation of 1. 

Both, esters and tertiary amino groups are tolerated, giving rise to products 6f and 6h which are useful as centers for dendrimeric structures. The pentakisalde-hyde 6g was obtained from 4-bromobenzaldehyde protected as the ethylene glycol acetal. Attempts to use heterocyclic bromides for arylation were hitherto unsuccessful. 

Therefore, the carbonyl group is first protected as an ethylene glycol acetal. 

Syntheses of acetals of atropaldehyde have been reported previously, but all required either multistep sequences or difficultly accessible starting materials.5,6 Thus the ethylene glycol acetal has been prepared from 2-phenylpropanal in a three-step procedure.5 Ring openings of dihalocyclopropanes to give acetals are well known.7-10 The reaction of l,l-dichloro-2-phenylcyclopropane with methanolic sodium methoxide has been shown to give 1-phenyl-2,2-dimethoxycyclopropane. u... 

The only described preparatively useful route to atropaldehyde is the hydrolysis of the ethylene glycol acetal mentioned above.5... 

From the diacetate ester (Figure 7.13), an ion-molecule complex consisting of the neutral ketene and the complementary alcoholate is formed. Either this complex dissociates to yield the ethylene glycol acetate anion A, which further fragments to yield the acetate anion E, or a proton transfer from the ketene to the alcoholate occurs in the complex, which after dissociation yields the ynolate ion G. 

SYNS 1,2-ETHANEDIOL DIACETATE ETHYLENE ACETATE ETHYLENE GLYCOL ACETATE ... 

C12H20O2 citral ethylene glycol acetal 66408-78-4 505.75 44.437 2 24712 C12H2202 citronellyl acetate 150-84-5 502.15 44.091 1,2... 

---