Ether still

Attention is directed to the fact that ether is highly inflammable and also extremely volatile (b.p. 35°), and great care should be taken that there is no naked flame in the vicinity of the liquid (see Section 11,14). Under no circumstances should ether be distilled over a bare flame, but always from a steam bath or an electrically-heated water bath (Fig.//, 5,1), and with a highly efficient double surface condenser. In the author s laboratory a special lead-covered bench is set aside for distillations with ether and other inflammable solvents. The author s ether still consists of an electrically-heated water bath (Fig. 11, 5, 1), fitted with the usual concentric copper rings two 10-inch double surface condensers (Davies type) are suitably supported on stands with heavy iron bases, and a bent adaptor is fitted to the second condenser furthermost from the water bath. The flask containing the ethereal solution is supported on the water bath, a short fractionating column or a simple bent still head is fitted into the neck of the flask, and the stUl head is connected to the condensers by a cork the recovered ether is collected in a vessel of appropriate size. 

Catalytic vinylation has been appHed to a wide range of alcohols, phenols, thiols, carboxyUc acids, and certain amines and amides. Vinyl acetate is no longer prepared this way in the United States, although some minor vinyl esters such as stearates may still be prepared this way. However, the manufacture of vinyl-pyrrohdinone and vinyl ethers still depends on acetylene. 

A solution of 100 g. of c. p. concentrated sulfuric acid in 700 cc. of water is prepared in a 5-I. flask, 1500 cc. of cracked ice added, and the mixture shaken until ice forms on the outside of the flask. After about half of this solution has been poured into the cold ether solution of the imino ether, using a funnel to remove the excess ice, the mixture is shaken for exactly fifteen seconds (Note 4), allowed to settle, and the layers separated. The remaining acid is added to the ether layer in two portions, the mixture each time being shaken for fifteen seconds, and separated. Since the ether solution, although now free of the imino ether, still contains a small amount of ethyl phenylaceto-acetate, it is saved to be combined with the main portion later. 

The order of basicity found for the cyclic sulphides on the basis of ring size is 5>6>4>3. This order is different from that in cyclic ethers. Stille and Empen [66] state that this difference has been ascribed to the differences in heteroatom size, differences in ring size (ring strain), and also to differences in polarizability between oxygen and sulphur atoms. Basicity did not correlate well with reactivity in the sulphide series. Ring strain seemed to be more important. However, it should be noted that the reactivity measured in the sulphide case was in homopolymerizations. Very few copolymerization studies have been carried out so far. 

Historically speaking, the first TPEs belong to the PUR family, but since 1950 they were joined by block polymers assembled from hard blocks of polymeric styrene that are attached to soft blocks of polymeric ethylene and butylene, butadiene, or isoprene monomers, and in the 1960s there appeared hard blocks of polymeric aromatic polyesters joined to soft blocks of oligomeric or polymeric ethers. Still later, hard polyamide blocks derived from aromatic dicar-boxylic acids were combined with soft blocks of aliphatic components and the world of TPEs continues to expand. 

The organomagnesium-halide reagent in this reaction was prepared in EtjO which then was removed. In some such reactions, small portions of the ether still may be present. 

Some of the compound ethers still contain a portion of the acid hydrogen which, being replaceable by another radical or by a metal, communicates acid qualities to the substance, which is at the same time a compound ether and a true acid. 

Anionic polymerization of o-divinylbenzene was examined by Aso et al. [294]. The authors used n-BuLi, phenyllithium, and naphthalene/alkali metal in THF, ether, dioxane, and toluene at temperatures between —78 and 20 °C. Generally, it was found that as with radical and cationic initiators, a competition between cyclopolymerization and conventional 1,2-polymerization occurs, with the tendency for cyclization to be lower than with the other mechanisms. The polymerization initiated with the lithium organic compounds resulted in polymers with up to 92% double bonds per monomer unit (THF, 20 °C). Polymerization with lithium, potassium, and sodium naphthalene also showed a rather weak tendency for cyclization. In THF at 0°C and 20 °C the cyclization tendency increased with decreasing ionic radii of the counter cation, while in dioxane the reverse effect was observed, and in ether still another dependence was found (K > Li > Na). Nitadori and Tsuruta [299] used lithium diisopropyl amide in THF at 20 °C to polymerize m- and p-divinylbenzene. The authors obtained soluble products with molecular weight up to 100 000 g/mol (GPC) and showed the polymers to contain pendant double bonds by IR and NMR spectra. It seemed to be important that a rather large excess of free amine (the initiator was formed by reaction of -BuLi with excess diisopropylamine) was present in the polymerization mixture. In later studies [300,301] a closer view was taken on polymerization kinetics and the steric course of the polymerization reaction. 

When a fatty alcohol is ethoxylated, the resulting ether still has a terminal -OH, which can subsequently be sulfated to give the alcohol ether sulfate (AES) ... 

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