Di-t-Butyl ether

When a Me3Si group is removed from an organic molecule with hydroxide ion, the product is not the silanol as you might expect but the silyl ether hexamethyldisiloxane . Di-t-butyl ether could not Chapter52that... 

The value of ((i(H2)=0.4 appears to be the most reliable. The higher values including 0.5 which are still currently used would give primary processes) > 1 for many systems such as N2O (166), methanol (127), ethanol (128), isopropanol (129), di-t-butyl ether (87) and methyl-n-propyl ether (88), an unreasonable result. However, using <(>(H2)=0.4, (Ksum of primary processes) approaches or equals but never exceeds unity. If normalized to the same actlnometer quantum yield value, results from different laboratories, for example, the H2 yield of 1M methanol in water ( cf. 127,166-168), agree within 10 percent. 

More recently, detailed studies were presented by the reviewers group on diethyl ether (177), methyl n-propyl ether (88), t-butyl methyl ether (86), di-t-butyl ether (87), and 2-methoxyethanol (159), and more restricted studies (178) on ethyl n-propyl ether, ethyl isopropyl ether. Isopropyl methyl ether, and n-butyl methyl ether. 

Excepting di-t-butyl ether (see below), the most important primary process is the homolytic C-0 bond scission (reactions 27 and 28). 

Carbon-carbon bond scission is rather unimportant in diethyl ether (< 0.5%) and methyl n-propyl ether (< 2%), but is enhanced somewhat in t-butyl methyl ether (= 4.5%) and di-t-butyl ether (7%). The reverse has been found regarding the formation of hydrogen. 

The most striking phenomenon in this series of ethers is the high quantum yield of molecular decomposition in the case of di-t-butyl ether (iji = 0.8 = 80%). Usually, the molecular processes do not exceed 20 percent. This difference has been considered to reflect the strain already present in the ground state of the di-t-butyl ether molecule. 

Problem 14.6 Give the alkene and alcohol needed to prepare the following ethers by alkoxymercuration-demercuration (a) diisopropyl ether, (b) 1-methyl-1-methoxycyclopentane, (c) 1-phenyl-1-ethoxypropane, (d) di-t-butyl ether. 

Problem 14.43 Why is di-t-butyl ether very easily cleaved by HI ... 

Use Learning By Modeling to make models of water, methanol, dimethyl ether, and di-te/t-butyl ether. Minimize their geometries, and examine what happens to the C—O—C bond angle. Compare the C—O bond distances in dimethyl ether and di-te/t-butyl ether. 

DI-t-BUTYL PEROXIDE DI-n-BUTYL SULFONE DIETHYLENE GLYCOL DIETHYL ETHER... 

Langer, S., E. Ljungstrom, I. Wangberg, T. J. Wallington, and O. J. Nielsen, Atmospheric Chemistry of Di-fert-butyl Ether—Rates and Products of the Reactions with Chlorine Atoms, Hydroxyl Radicals, and Nitrate Radicals, Int. J. Chem. Kinet, 28, 299-306 (1996). 

As was the case for the alkyl hydroperoxides in reaction 4, the enthalpies of the oxy-gen/hydrocarbon double exchange reaction 8 for dialkyl peroxides are different depending on the classification of the carbon bonded to oxygen. For R = Me, Et and t-Bu, the liquid phase values are —4, 24.6 and 52.7 kJmol-1, respectively, and the gas phase values are 0.1, 25.7 and 56.5 kJmol-1, respectively. For the formal deoxygenation reaction 9, the enthalpies of reaction are virtually the same for dimethyl and diethyl peroxide in the gas phase, —58.5 0.6 kJ mol-1. This value is the same as the enthalpy of reaction of diethyl peroxide in the liquid phase, —56.0 kJ mol-1 (there is no directly determined liquid phase enthalpy of formation of dimethyl ether). Because of steric strain in the di-tm-butyl ether, the enthalpy of reaction is much less negative, but still exothermic, —17.7 kJmol-1 (lq) and —19.6 kJmol-1 (g). 

Tetramethyl-3-oxapentane (di-fe/t-butyl ether) is very unstable to acidic reagents. Devise a synthesis of the compound that you think might have a reasonable chance for success. Give your reasoning. 

The observation that DTBN is partially destroyed with formation of di-f-butyl-hydroxylamine and di-t-butylhydroxylamine ethers when employed as a quencher of the photoaddition reactions of 50 implicates DTBN as a free radical scavenger63. The free radical scavenging is thought to occur in parallel with quenching and not to be related to the quenching because the efficiency of quenching by DTBN is not... 

Bromomagncsium 4-methylbenzenetellurolate and t-butyldichlorophosphane reacted in diethyl ether to give t-hutylphosphanidene his[4-methylphenyl tellurium] and l,2-bis[4 -methylphenyltelluro)-l,2-di(t-butyl)diphosphane. Only the diphosphane derivative was obtained in pure form. The t-butylphosphanidene bis[4-methylphenyl tellurium] was detected in solution by 3 P-NMR spectroscopy3. 

A very interesting reaction of an epoxide with WC16 provides the trans-dichloride <07TL8388>. The reaction proved compatible with a number of functional groups including esters, sulfones, and even silyl ethers (with the addition of 2,6-di-t-butyl pyridine). Olefins and alcohols were converted to the chlorides. 

Polymerization of several representative monomers of vinyl and cyclic ethers was shown to be initiated efficiently by this particular two component system in which o-phthalaldehyde was used as promoter (Table 4). The proposed mechanism was further supported by the polymerization experiments in the presence of a strong scavenger, 2,6,6-di-t-butyl-4-methylpyridine (DBMP). Experiments in the presence of DBMP failed to produce any precipitable polymer indicating that initiation involves protons generated according to the above reaction. 

To 4-amino-1-benzylpiperidine (25 g) dissolved in 150 ml chloroform was added di-t-butyl dicarbonate (31.4 g) with ice cooling followed by stirring 2 hours at ambient temperature. The reaction mixture was diluted with chloroform, washed with water, dried, and concentrated. After recrystallizing from hexane/diisopropyl ether, 35.65 g of product was isolated. 

The salt is used as reagent to convert alcohols into alkyl iodides. This reaction proceeds with inversion of configuration on the C atom bearing the - OH group. N-Methyl-N,N -di-t-butyl-carbodiimide tetrafluoroborate is used as condensation agent in the synthesis of ethers and esters. ... 

Ethers. Low yields of several compounds were obtained when ethvl ether was heated at 130-140 under ethylene pressure in the presence of di-t-butyl peroxide and hydrochloric acid (Expt. 26, Table V). Ethylation took place in the normal fashion to yield ethyl sec-butyl ether by monoethylation together with at least three ethers having eight carbon atoms di-sec-butyl ether, (ethylation at both secondary carbon atoms of the ethyl ether), ethyl 1-methyl-l-ethylpropyl ether (ethylation at the tertiary carbon atom of the primary product) and ethyl-1-methylpentyl ether formed by telomerization of the primary radical with two molecules of ethylene). Some Cio ethers were also formed. 

Ethyldioxane (IJ) was a product of the reaction of p-dioxane with ethylene in the presence of hydrochloric acid and di-t-butyl peroxide at 130-140 C (Expts. 29 and 30). However, the major product was bis-(2-chloroethyl) ether ( ) and a smaller amount of... 

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