Acetylenic ethers properties

One class of materials with some inherent PSA properties includes polyvinyl-ethers. Vinyl ether monomers are industrially derived from the reaction of acetylene with alcohols [117]. The most common alcohols used are methanol, ethanol or isobutanol. A generic structure of the vinyl ether is shown below ... 

Many engineering thermoplastics (e.g., polysulfone, polycarbonate, etc.) have limited utility in applications that require exposure to chemical environments. Environmental stress cracking [13] occurs when a stressed polymer is exposed to solvents. Poly(aryl ether phenylquin-oxalines) [27] and poly(aryl ether benzoxazoles) [60] show poor resistance to environmental stress cracking in the presence of acetone, chloroform, etc. This is expected because these structures are amorphous, and there is no crystallinity or liquid crystalline type structure to give solvent resistance. Thus, these materials may have limited utility in processes or applications that require multiple solvent coatings or exposures, whereas acetylene terminated polyaryl ethers [13] exhibit excellent processability, high adhesive properties, and good resistance to hydraulic fluid. 

Acetylene is a simple asphyxiant and anaesthetic. Pure acetylene is a colourless, highly flammable gas with an ethereal odour. Material of commercial purity has an odour of garlic. Its physical properties are shown in Table 8.4. 

Ethyl vinyl ether, 1 254, 258 derivation from ethanol, 10 557 physical properties of, l 255t Ethynylation, acetylene, 1 181, 231-249 Etretinate, 25 790 Etridiazole, 23 629... 

POLYVINYL ALKYL ETHERS. These products have properties which range from sticky resins to elastic solids. They are obtained by the low-temperature cationic polymerization of alkyl vinyl ethers having the general formula ROCH=CH-. These monomers are prepared by the addition of die selected alkanol to acetylene in the presence of sodium alkoxide or mercury(ll) catalyst, As shown by the following equations, the latter yields an acetal which must be thermally decomposed to produce the alkyl vinyl ether. 

The chemical properties and uses of propargyl alcohol has three potentially reactive sites (1) a primary hydroxyl group (i.e., CH2OH), (2) a triple bond (-C=C-), and (3) an acetylenic hydrogen (-C=CH) that makes the alcohol an extremely versatile chemical intermediate. The hydroxyl group can be esterified with acid chlorides, anhydrides, or carboxylic acids, and it reacts with aldehydes or vinyl ethers in the presence of an acid catalyst to form acetals. At low temperatures, oxidation with chromic acid gives propynal or propynoic acid ... 

Rezac, M. E., and Schoberl, B. (1999). Transport and thermal properties of poly (ether imide)/acetylene-terminated monomer blends, J. Membrane Sci. 156, 211. 

In fact, the solubility of certain acetylenic Grignard reagents in diethyl ether is low and, in some instances, oily matter separates from solution. In this case, diethyl ether may be replaced by another solvent with higher solubility, but oily or slurry-like Grignard reagents have little effect on the reaction processes. Tetrahydrofuran shows excellent solubility properties and is used extensively for the preparation of acetylenic Grignard reagents. 

Properties Heavy, colorless, corrosive liquid chloroform-like odor. D 1.593 (25/25C), bp 146.5C, fp —43C, bulk d 13.25 lb/gal (25C), refr index 1.4918 (25C), flash p none. Soluble in alcohol and ether slightly soluble in water. Nonflammable. Derivation Reaction of acetylene and chlorine and subsequent distillation. 

The preparation, properties, and reactions, especially polymerization, of products from the acetylene-carbon monoxide reaction, such as acrylic acid and its esters, are given by Blout and Mark (8) and by Schildknecht (98). Similarly treated therein are the vinyl esters from acetylene and carboxylic acids, and other vinylation products such as vinyl ethers. The esterification of organic acids with olefins is reviewed by Morin and Bearse (76). 

Silyl ynol ethers have highly characteristic spectral properties. The triple bond stretching in the IR of siloxyalkynes is at 2260-2270 cm" which compares with that of ynol esters and alkoxyacetylenes (see Sections III and IV of the present review) ". Particularly noteworthy and characteristic are the acetylenic carbon signals in the NMR. The... 

In this work, we develop a consistent set of oxygenated peroxy-hydrocarbon and acetylene-alcohol groups derived from the thermodynamic properties data of a set of hydroperoxides, peroxides, ethers and alcohols determined in previous chapters. 

The physical properties of alkynes (Table 9-1) are similar to those of alkanes and alkenes of similar molecular weights. Alkynes are relatively nonpolar and nearly insoluble in water. They are quite soluble in most organic solvents, including acetone, ether, methylene chloride, chloroform, and alcohols. Many alkynes have characteristic, mildly offensive odors. Acetylene, propyne, and the butynes are gases at room temperature, just like the coitesponding alkanes and alkenes. In fact, the boiling points of alkynes are nearly the same as those of alkanes and alkenes with similar carbon skeletons. 

Halide ions, especially F , are weak bases in aqueous solution. However, in dry aprotic solvents Et4N F effectively induces elimination of HBr from 2-bromoethylbenzene (7). The ammonium chloride and bromide only promote halogen exchange. At 80°, the fluoride decomposes into EtjN, HF, and ethylene, thus demonstrating the high protophilicity of the hard fluoride ion. This same property is also shown by its usefulness for generating dihalo-carbenes. Naked fluoride ion (cation sequestered by a crown ether) promotes facile elimination of haloethylenes to form acetylenes and allenes (8). 

Solid-state heteropoly compounds have interesting catalytic properties [117] and have found applications in olefin and acetylene hydration and alcohol dehydration [90fj. Adsorption of nonpolar molecules (hydrocarbons) reaches saturation at amounts lower than monolayers ("surface-type" adsorption). However, it is characteristic of heteropoly compounds that adsorption of polar molecules (alcohols, ethers, amines) takes place in amounts that exceed by many times (10-10 ) mono-... 

SYNTHESIS AND PROPERTIES OF ACETYLENE TERMINATED ARYL-ETHER OLIGOMERS... 

The objective of this work is to synthesize a series of acetylene terminated aryl-ether systems for the purpose of correlating their thermal and thermal mechanical properties with molecular structure. 

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