Isobutylene oxide

Isobutylene oxide is produced in a way similar to propylene oxide and butylene oxide by a chlorohydrination route followed by reaction with Ca(OH)2. Direct catalytic liquid-phase oxidation using stoichiometric amounts of thallium acetate catalyst in aqueous acetic acid solution has been reported. An isobutylene oxide yield of 82% could be obtained. 

Direct non-catalytic liquid-phase oxidation of isobutylene to isobutylene oxide gave low yield (28.7%) plus a variety of oxidation products such as acetone, ter-butyl alcohol, and isobutylene glycol ... 

Hydrolysis of isobutylene oxide in the presence of an acid produces isobutylene glycol ... 

B. 2,5-Dimethyl-2,4-hexanediol. Isobutylene oxide (7.2 g, 0.10 mol) (Note 7) is added dropwise from the pressure-equalizing funnel to the LDBB solution in THF at -78°C at such a rate (the addition lasts for 8-12 min) that the temperature inside the flask does not exceed -78°C. After all the epoxide has been added (8-11 min), the solution becomes deep red. After 5 more minutes of stirring, isobutyraldehyde (7.2 g,... 

Isobutylene oxide was used as purchased from Tokyo Kasei Kogyo Co., Ltd., Tokyo, Japan (also available from TCI America). 

Isobutylene oxide Propane, 1,2-epoxy-2-methyl- (8) Oxirane,... 

Isobutylene sulfide is prepared according to published procedures from isobutylene oxide and potassium thiocyanate.8 A 250-mL, round-bottomed flask, fitted with a magnetic stir bar and addition funnel, is charged with 97 g (1.0 mol) potassium thiocyanate and 100 mL water. With vigorous stirring, 72 g (90.0 mL, 1.0 mol) isobutylene oxidef is added dropwise over 5 h via the addition funnel. Owing to the exothermicity of the reaction, slow addition is... 

There is one last experimental result arguing for a high activation energy for internal ft—C—H abstraction. When Steps 11" and 12 compete, epoxidation (Step 11") always seems to be faster than olefin formation (Step 12). This is true in the HC1 catalyzed, chain decomposition of ter -Bu202 which produces isobutylene oxide and negligible isobutene (2) via a peroxyalkyl radical. Similar behavior is observed from the addition of H02 and R02 to olefins, which produce mainly ethers or epoxides at rapid rates (12). Note that although we estimate A12 — 1013 4 sec."1 and An" -— 10115 sec. 1, Step 12 is endothermic by -— 11 to 13 kcal., while Step 11" is exothermic by 10 to 17 kcal. A reasonable estimate for Ei2 is 20 kcal., while En" has an upper limit of 16 kcal., and some data (12) point to a value closer to 10 kcal. 

Among the many alkyl-substituted epoxides that have hi n reported to undergo hydration under various conditions are propylnm oxide, isobutylene oxide, 1,2-epoxybutone, trimethylethylene oxide, and others-. . . , jtf, i w. . shown in JSq, (50 ). 

Treatment of isobutylene oxide with methanol (Eq. 653) in the presence of a trace of boron trifluoride is reported to give only 2-methoxy-2-tnethyl-1 -propanol, along with polymerisation products and wcbutyraldehyde (isolated ae its dioxolane derivative).1 31 Ti in perhaps surprising that no l-methoxy 2-i etbyl-2-propand was formed at all under these conditions. 

Culvenor and co-workers 4M have utilized 2,4-dimuot.hio phenol to cleave a number of ethylene oxides. Notable examples include ethylene oxide itself, propylene oxide, isobutylene oxide, epichlorohydrin, and gjycidol (Eq. 667). All undergo addition u, tIn-K O OH... 

Ethylene oxide, propylene oxide, and isobutylene oxide yield P-thiocyanato alcohols on treatment with ioe-eold, slightly acidifo-d solutions of ammonium or potassium iaothiooyanate.1408-,7IS Those... 

Among alkyl-substituted ethylene oxides known to umletrn cleavage on treatment with sodium sulfite are propylene oxide, isobutylene oxide, 1,2-epoxybutane, 1,2-epoxyoctane, and 2,3-cpow-butane.1 75 These reactions with sodium sulfite constitute the bani-, ffrail analytical method developed by Swan1875 for the estimation <[Pg.179]

Atom (Eq. 791)- Epoxides investigated in this manner included ethylene oxide, propylene oxide, isobutylene oxide, cm- and lmtw-2,8-epoxybutane, 2.a-opoxy-2 methylbutane1 and 2,3-epoxy-2,a dimethvl butane l4s , ... 

Propylene oxide, isobutylene oxide, and 2,3-epoxy bub uu J undergo cleavage readily on treatment with sodium azide (Eq. 7). 

Peroxide and hydroperoxide ions. A patent disclosure h Barueoh and Payne101 has described addition of teri-bntylliydi- peroxide to ethylene oxide, propylene oxide, and isobutylene oxide in ether, in the presence of either basic or acidic catalysts. The <°rt-Imtylperoxide ion, like other nucleophiles, apparently prefers to uttar. c... 

Unaymmetrical epoxides were said to give rise to mixed products, although experimental details were not included. Eqs. (908) and (900) illustrate the action of diethyl phosphite in base on propylene oxide mid isobutylene oxide. The latter undergoes preliminary isomerisation to wobutyrsddehyde before yielding a conventional carbonyl adduct. 

Pritchard and Long1416-141 studied the distribution of lsO in products obtained on hydration of propylene oxide and isobutylene oxide in Hs180, both in alkaline and in acid solutions (Eqs. 611 and 612). Their results are consistent with the premise that attack by water occurs predominantly on the terminal epoxide carbon atom, unless an... 

Still another active hydrogen component utilized in this reaction has been ethyl cyanoacetato (Eq. 870), the sodium salt of which wsa condensed with propylene oxide or isobutylene oxide. 6 Similarly, ethyl aodioaoetoftcetate (Eq. 878) has been added to propylene oxide. Terminal attack is the rule in all these instances. 

More recent work by Hopff and Koulen 0 further broadened the scope of the reaction by including an assortment of dieubstituted benzenes, and also biphenyl and acenaphthene. Somerville and Spoerri,1 05-1 4 moreover, have examined the action of isobutylene oxide and 2,3-epoxybutane on benzene in the presence of aluminum chloride Mixtures of alcohols and hydrocarbons were isolated, as in previous work. 

At usual decomposition, formation of the final products (isopropyl alcohol and isobutylene oxide or acetone and ethane) requires one initial molecule. 

In a review article Eastham (12) reports that treatment of isobutylene oxide with borontrifluoride leads to dimer without any polymer but the reaction conditions were not mentioned. On the other hand, Vandenberg (13) described the polymerization of the same monomer with borontrifluoride to give 60% of polymer containing substantial amounts (ca. 27%) of high boiling volatiles which were supposed to be a mixture of cyclic oligomers. 

Allenyl sulfides have been converted into their a-lithio derivatives by deprotonation with n-BuLi in THF at —78 °C1092 or in the presence of TMEDA1093,1094. For example, compound 775 reacted with isobutylene oxide to give compound 776, after cyclization (Scheme 201). This dihydropyran 776 was transformed into atlantone 777, as a mixture of Z/E diastereomers, by treatment with HgCl2 in wet acetonitrile1092. 

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