Olefin ether

Ring opening polymerization of cyclic monomers to yield thermoplastic polymers has been studied by a number of investigators [1-19] over the years. A variety of cyclic monomers ranging in structures from the more commonly encountered olefins, ethers, formals, lactones,... 

Oxydipropionitrile Paraffins, cycloalkanes, olefines, ethers, alkylbenzenes, acetates, aldehydes, alcohols, acetals and ketones... 

Other factors influencing the olefin/ether ratio are the partial pressure of the starting alcohol because olefin-forming and ether-forming reactions obey different kinetics (see Sect. 2.2.3) and the nature of the catalyst. 

Another fine distinction among salt catalysts was obtained by following the activity and olefin/ether selectivity of metal sulphates in the dehydration of ethanol and 1-propanol. A linear correlation between the electronegativity of the metal ion and the activity has been found, but the selectivity gave a curve with a minimum [51]. 

CDTECH, Inc. Ether Refinery C4 and C5 streams Produces high iso-olefin/ether products by hydrogenation and isomerization 5 1992... 

A mixture of magnesium and magnesium iodide in ether is used to prepare the cyclic olefinic ethers, dioxene and dioxadiene, from the corresponding dichloro- and tetrachloro-dioxanes, respectively. ... 

Two techniques are commonly used in the preparation of olefinic ethers from halo ethers. The first involves heating a /5-halo ether with fused or powdered potassium hydroxide. This method is typified by the conversion of -phenoxyethyl bromide to phenyl vinyl ether (69%) and, /5 -dichlorodiethyl ether to divinyl ether (61%). In the latter case, yields are improved in the presence of ammonia gas. In the second procedure, an aliphatic or aromatic chloro ether is heated with pyridine to 115°. This method is of value in the preparation of several methoxystyrenes. Chloroalkylation of the aromatic ether is followed by dehydrohalogenation. 

K platinum-on-asbestos catalyst at 290° is used in the conversion of t liethyl acetal to ethyl vinyl ether (42%). Ketals of the type C(OCHj)jCHj are readily split by heating with a small amount of p-I oluenesulfonic acid to yield substituted vinyl ethers of the type t lC(OCHj)=CHj (92%). In the presence of excess of a higher alcohol, fl OH, the olefinic ether corresponding to this alcohol, RC(OR )=CHj, is formed in high yield. Similarly, treatment of alkoxy ketals with acid I atalysts gives alkoxy dienes and dialkoxy olefins. ... 

Reaction with olefins. The addition of dinitrogen tetroxide alone is not generally a useful synthetic system because of the formation of several products. However, Stevens and Emmons found that the reaction of dinitrogen tetroxide with an olefin (ether solution, N2) in the presence of excess iodine led to /3-nitroalkyl iodides, usually in good yield ... 

The aliphatic groups bonded to the ether linkage are moderately strongly deshielded. In addition, the aliphatic groups bonded to an olefinic ether linkage are more strongly deshielded than those of an aliphatic ether substituent. 

On autoxidation, compounds containing activated C-H bonds (olefins, ethers, alcohols, aldehydes, ketones, and hydrocarbons) always afford in the... 

Phosphorus pentoxide, if used with 85% H3PO4 and potassium iodide, will convert olefins, ethers and alcohols to iodides (12.272). 

A soln. of 8-benzyloxy-2,6-dimethyl-2,3-epoxyoctane in ether added to /-Pr2NH and 4 eqs. H2O in the same solvent under a balloon of SiF4 at 0°, the mixture stirred for 1 h, then quenched with aq. KF -> 8-benzyloxy-2,6-dimethyl-2-fluorooctan-3-ol. Y 91%. The method is short and is undertaken with conventional glass apparatus olefins, ethers and 1,2-disubstd. oxiranes (aliphatic) were unaffected, while mono-subst. aliphatic oxiranes polymerized. Stereoselectivity is illustrated by the formation of 5y -fluorohydrins. F.e.s. M. Shimizu, H. Yoshioka, Tetrahedron Letters 29, 4101 (1988) l-fluoro-2-hydroxysilanes s. Tetrahedron Letters 30, 967-70 (1989). 

Olefins Ethers Halocarbons Aromahcs Ketones Aldehydes Esters Alcohols Amines... 

Building on the proposed mechanism hy Hauffe, ° for metal oxide-catalysed dehydration of alcohols to form olefins, ethers and water which heavily relies on the assumption that the catalyst surface acts as semiconductor, Hasssan et al. purposively attempted to obtain a further insight into the mechanism of alcohol dehydration on pure cadmium oxide. On the basis of the experimental data involving kinetics of the dehydration reaction and the effect of pretreatment of the catalysts along with studies on lattice structure and specific surface areas, a mechanism for ethanol dehydration was put forward (Scheme 17.14). The proposed mechanism entirely depends... 

Taskinen E. Enthalpies of formation of olefinic ethers by G3(MP2)//B3LYP calculations. J Phys Org Chem. 2009 22 42-51. 

Pyrolysis GC of alkyl sulfates in the presence of phosphoric acid or P2O5 gives olefins of the same length as the original alkyl chain, with the double bond distributed along the chain (16). Pyrolysis without acid yields mainly a-olefins as opposed to internal olefins. Ether sulfates are distinguished from alcohol sulfates by the presence of the characteristic decomposition products acetaldehyde and 1,4-dioxane (19). 

Many organic compounds can also be prepared by isotopic exchange, often with the aid of acid or base catalysis. Many alcohols can be prepared by acid catalyzed exchange (see Grunwald et al., 1957, and previous papers) but the formation of olefins, ethers, and rearranged products causes difficulties in purification and reduces the yield considerably. 

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