Ethers, r-butyl

Peroxides. These are formed by aerial oxidation or by autoxidation of a wide range of organic compounds, including diethyl ether, allyl ethyl ether, allyl phenyl ether, dibenzyl ether, benzyl butyl ether, n-butyl ether, iso-butyl ether, r-butyl ether, dioxane, tetrahydrofuran, olefins, and aromatic and saturated aliphatic hydrocarbons. They accumulate during distillation and can detonate violently on evaporation or distillation when their concentration becomes high. If peroxides are likely to be present materials should be tested for peroxides before distillation (for tests see entry under "Ethers", in Chapter 2). Also, distillation should be discontinued when at least one quarter of the residue is left in the distilling flask. 

All of the above high-volume organic chemicals are obtained from petroleum or natural gas. This is why the modern organic chemical industry is frequently referred to as the petrochemical industry. The high-volume status of some of these compounds is due to their use to make others lower on the list. For example, ethylene is used to make ethylene dichloride, which, in turn, is used to make vinyl chloride. Ethyl benzene, made from benzene and ethylene, is used to make styrene. Methyl r-butyl ether is made from methanol and butylene, a captive intermediate for which production data is not available. 

Polynaphta Essence A process for making a linear olefin fraction for making methyl r-butyl ether to use as a fuel additive. Developed by IFP in 1996 replacing UOP s Catpoly process. 

Acetic acid Methyl r-butyl ether Phenol... 

However, care must be exercised in using molecular sieves for drying organic liquids. Appreciable amounts of impurities were formed when samples of acetone, 1,1,1-trichloroethane and methyl-r-butyl ether were dried in the liquid phase by contact with molecular sieves 4A (Connett Lab.Practice 21 545 1972). Other, less reactive types of sieves may be more suitable but, in general, it seems desirable to make a preliminary test to establish that no unwanted reaction takes place. For the principles of synthesis and identification see R. Szostak Molecular Sieves, Chapman Hall, London 1988, and for structure, synthesis and properties see R.Szostak Handbook of Molecular Sieves, Chapman Hall 1992. 

Church, C. D., J. F. Pankow, and P. G. Tratnyek, Hydrolysis of rm-butyl formate Kinetics, products, and implications for the environmental impact of methyl fe/r-butyl ether. Environ. Sci. Technol., 18,2789-2796 (1999). 

Treatment of alcohols with f-butyl dicarbonate (B0C2O) in the presence of anhydrous Mg(C104)2 at 40 °C in CH2C12 produces the corresponding r-butyl ethers. The proposed mechanism involves initial formation from the alcohol, ROH, of a mixed dicarbonate (40), which, complexes with the catalyst to form (41). This decomposes to the l-butyl ether (42) and C02 via a concerted mechanism (Scheme 12).41... 

This alcohol can be reacted with methanol in the presence of a catalyst to produce methyl-r-butyl ether. Although it is currently cheaper to make Ao-butyl alcohol from Ao-butcne (Ao-butylene), it can be synthesized from syngas with alkali-promoted zinc oxide catalysts at temperatures above 400°C (750°F). 

Methyl tertiary butyl ether (methyl-r-butyl ether, MTBE boiling point 55°C, flash point -30°C) has excited considerable interest because it is a good octane enhancer for gasoline (it blends as if it had a research octane number of 115 to 135). It also offers a method of selectively removing isobutylene from a mixed C4 stream, thus enabling the recovery of high-purity butene-1. Furthermore, methyl tertiary butyl ether can be isolated, then cracked to yield highly pure iso-butylene and methanol. 

The reaction for making methyl-r-butyl ether proceeds quickly and highly selectively by reacting a mixed butene-butane fraction with methyl alcohol in the liquid phase on a fixed bed of an acidic ion-exchange resin catalyst (Fig. 1). 

For NPLC, the three solvents selected were the same as those recommended by Snyder, except that methyl-r-butyl ether is substituted for ethyl ether. The (nonpolar) carrier solvent recommended is hexane, and the stationary phase is silica. 

Problem 14.6 Give the alkene and alcohol needed to prepare the following ethers by alkoxymercuration-demercuration (a) diisopropyl ether, (b) l -methyl-1-methoxycyclopentane, (c) l -phenyl-1-ethoxypropane, (d) di-r-butyl ether. -4... 

Etherol A process for making oxygenated fuels (e.g., methyl r-butyl ether) from C4 to C6 hydrocarbons by reacting them with methanol over an acid resin catalyst in a fixed-bed reactor under mild conditions. Developed by BP with Erdoel Chemie and first used in a refinery at Vohburg, Germany, in 1986. Four units were operating and one was under construction in 1988. 

Alkylation of levorphanol with A/,N-dimethylformamide di-f-butyl acetal gave the r-butyl ether,<50a) which was of reduced analgesic (MW, RTF) activity and receptor binding affinity and lacked antitussive actions. 

Most of the metallic oxidants which have been used for the oxidation of ethers have been based on oxides of the transition metals chromium, manganese and ruthenium, the latter being of greatest synthetic importance. The first reported example of the application of ruthoiium tetroxide in the oxidation of ethers tqipeared over 30 years ago in 1958, although an indication of its reactivity towards ethers had been obt ed some years before. In a systematic study which revealed the powerful oxidizing properties of the reagent, Berkowitz and Rylander demonstrated the quantitative conversion of tetrahydrofuran and R-butyl ether into y-butyrolactone and butyl butyrate, respectively. Significantly, no overoxidation was observed. Apart f m an unsuccessful attempt to oxidize ethylene oxide, no fitter attempts were made by the authors to examine further the scope of this novel transformation. In a series of subsequent publications and a patent, Wolf and his coworkers went on to exploit the reaction in the preparation of aldosterone and relr steroids (equation 1). 

The Kharasch-Sosnovsky reaction may be carried out in the presence of caiboxylic acids to introduce the acyloxy moiety of the acid used, and may also be conducted photochemically at room temperature using UV irradiation. Peroxy acids, diacyl peroxides, and peroxyphosphates and peroxyphospho-nates are alternative oxidants. r-Butyl hy operoxide may also be used in place of peroxy esters with broadly similar results, although formations of mixed peroxides and r-butyl ethers can then compete with allyl ester production. 

Dowanol PnB Propylene glycol mono r -butyl ether (C7H16O2) DOW 171 63 A III... 

Introduction. In the equations, VBE will be used to depict the valinol r-butyl ether portion of the formamidine, while the f-leucinol methyl ether portion will be abbreviated LME. ... 

---