Ethere cyclic

Aliphatic carboxylic acids Alkyl ethyl ethers Cyclic polyethers Phosphorous compounds Rearrangement peak in dioxanes... 

Considerable interest remains in catalyzed hydrogen-transfer reactions using as donor solvents alcohols, glycols, aldehydes, amides, acids, ethers, cyclic amines, and even aromatic hydrocarbons such as alkylben-... 

Studies on the cationic polymerization of cyclic ethers, cyclic formals, lactones and other heterocyclic compounds have proliferated so greatly in the last few years that a detailed review of the evidence concerning participation of oxonium and analogous ions in these reactions cannot be given here. Suffice it to say that there is firm evidence for a few, and circumstantial evidence for many such systems, that the reactive species are indeed ions and there appears to be no evidence to the contrary. A few systems will be discussed in sub-sections 3.2 and 4.4. 

An interesting observation should be made concerning the dependence of the physical properties on molecular cyclicity, since it will have a significant effect on the formulation of electrolytes for lithium ion cells. While all of the ethers, cyclic or acyclic, demonstrate similar moderate dielectric constants (2—7) and low viscosities (0.3—0.6 cP), cyclic and acyclic esters behave like two entirely different kinds of compounds in terms of dielectric constant and viscosity that is, all cyclic esters are uniformly polar (c = 40—90) and rather viscous rj = 1.7—2.0 cP), and all acyclic esters are weakly polar ( = 3—6) and fluid (77 = 0.4—0.7 cP). The origin for the effect of molecular cyclicity on the dielectric constant has been attributed to the intramolecular strain of the cyclic structures that favors the conformation of better alignment of molecular dipoles, while the more flexible and open structure of linear carbonates results in the mutual cancellation of these dipoles. 

Chromium-Containing Ionic Species Chromate Ion, Hexavalent Chromium Cobalt Copper Cyclic Ethers Cyclic Ethers Dioxane-1,4 Ethylene Oxide... 

Naito et al.si have reported that the addition of oxirane derivatives to C02 is catalyzed by potassium carboxylates or carbonates in the presence of a crown ether cyclic carbonates (42) constitute the main product. 

Cyclic ethers, cyclic acetals, and some vinyl compounds can be polymerized by cationic processes. Photoinitiation of these polymerizations by ultraviolet light are known (12,106). Some extension of direct photolytic sensitization of cationic processes to visible wavelengths is obtained by the use of colored diazonium salts as initiators. For example, Schlesinger (11a) used diazonium salts substituted in the para position with electron withdrawing groups, but sensitivity was limited to the blue to green regions of the spectrum. 

Glycol ethers Cyclic siloxanes 2-Butoxy ethanol... 

Gas Chrom Q (100-200 mesh). 160°. diazomethane and butaneboronic acid as pyridoxine 0-methyl ether cyclic butaneboronate. ... 

The second type of monomer for step-growth polymerization contains two different functional groups. Examples in this category include hydroxy acids such as lactic acid (or hydroxy esters [Equations 1-3]), and amino acids. A third type includes cyclic monomers such as lactones, lactams, and cyclic ethers. Cyclic monomers polymerize by ring-opening polymerization. Some, as we said, proceed by step-growth and some by chain-growth mechanisms. 

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