2-Methylpropene oxide

The effect of chain length on the catalytic performance was investigated using a series of co-bromo-2-methylalkenes. In all cases the predominant enantiomer produced had the -configuration except for 3-bromo-2-methylpropene oxide, which was predominantly in the S-form due to the priority switch [274], The short propene and butene derivatives were converted quantitatively whereas the longer pentene, hexene and heptene substrates failed to convert completely. Many other functional groups such as carboxylic ester, methoxy, acetoxy and carbonic ester are accepted by the system. The epoxidation fails, however, for 4-hydroxy-2-methyl-l-butene as substrate [270]. 

In the presence of H3O, 2-methylpropene oxide undergoes chain-growth polymerization such that nucleophilic attack occurs at the more substituted end of the epoxide. Draw a stepwise mechanism for this process, and explain this regioselectivity. 

Isobutyl alcohol, isobutanol, 2-methyl-propanol, isopropyl carbinol, Me2CHCH20H. B.p. 108°C. Occurs in fusel-oil. Oxidized by potassium permanganate to 2-methyl-propanoic acid dehydrated by strong sulphuric acid to 2-methylpropene. 

Cyclohexanone, 23,35 Cyclohexene oxide, 137 Cyclohcxyl methyl ether, 137 l-Cydohexyl-2-methylpropene, 68-9 ( )-l-Cyclohexyl-2-trimethyl ilylethene, 12 (Z)-l-Cyclohexyl-2-trimethylsilylelhene, 12 l-Cydohcxyl-2-trimethylsilylethyne, 12 (2-Cyclohexylidene-eihyl)trimethylsilane, 29 Cyclopentadec-2-ynone, 48 Cydopentadiene, 25 Cyclopentanone, 72 Cyclopentenones, 15 Cyclopropanone, 133... 

The reactions of intramolecular isomerization occur and are important in the oxidation of natural and synthetic rubbers. The peroxyl radical addition to the double bond occurs very rapidly. For example, the peroxyl radical adds to the double bond of 2-methylpropene by 25 times more rapidly than abstraction of hydrogen atom from this hydrocarbon (see Chapter 4). Therefore, the oxidation of polymers having double bonds proceeds as a chain process with parallel reactions of P02 with double and C—H bonds including the intramolecular isomerization of the type [12] ... 

Methylperhydrindanes, 20 281 2-Methyl-1-propanol, reactions over reduced nickel oxide catalyst, 35 357 2-Methylpropene, vibrational spectra, 41 97-100... 

Indenopyrene, see Indeno[l,2,3-crf pyrene l//-Indole, see Indole Indolene, see Indoline Inexit, see Lindane Inhibisol, see 1,1,1-Trichloroethane Insecticide 497, see Dieldrin Insecticide 4049, see Malathion Insectophene, see a-Endosulfan, p-Endosulfan Intox 8, see Chlordane Inverton 245, see 2,4,5-T lodomethane, see Methyl iodide IP, see Indeno[l,2,3-crf pyrene IP3, see Isoamyl alcohol Ipaner, see 2,4-D IPE, see Isopropyl ether IPH, see Phenol Ipersan, see Trifluralin Iphanon, see Camphor Isceon 11, see Trichlorofluoromethane Isceon 122, see Dichlorodifluoromethane Iscobrome, see Methyl bromide Iscobrome D, see Ethylene dibromide Isoacetophorone, see Isophorone a-Isoamylene, see 3-Methyl-l-butene Isoamyl ethanoate, see Isoamyl acetate Isoamylhydride, see 2-Methylbutane Isoamylol, see Isoamyl alcohol Isobac, see 2,4-Dichlorophenol Isobenzofuran-l,3-dione, see Phthalic anhydride 1,3-Isobenzofurandione, see Phthalic anhydride IsoBuAc, see Isobutyl acetate IsoBuBz, see Isobutylbenzene Isobutane, see 2-Methylpropane Isobutanol, see Isobutyl alcohol Isobutene, see 2-Methylpropene Isobutenyl methyl ketone, see Mesityl oxide Isobutyl carbinol, see Isoamyl alcohol Isobutylene, see 2-Methylpropene Isobutylethylene, see 4-Methyl-l-pentene Isobutyl ketone, see Diisobutyl ketone Isobutyl methyl ketone, see 4-Methyl-2-pentanone Isobutyltrimethylmethane, see 2,2,4-Trimethylpentane Isocumene, see Propylbenzene Isocyanatomethane, see Methyl isocyanate Isocyanic acid, methyl ester, see Methyl isocyanate Isocyanic acid, methylphenylene ester, see 2,4-Toluene-diisocyanate... 

A general method for the synthesis of pyrimidine A-oxides from amidoximes is described. The conversion involves treatment of various carboxamide oximes 325 with 1,1,3,3-tetramethoxypropane, 2,4-pentanedione or 3-ethoxy-2-methylpropenal in the presence of CF3COOH to afford pyrimidine 1-oxides 326 (equation 141) . 

Reactions 3 and 8. One of the more puzzling features of the oxidation of 2-methylpropane between 155° and 300°C. is the remarkable transition from a reaction producing about 1% or less 2-methylpropene at 155°C. to one producing 80% 2-methylpropene at 300°C. If the olefin and other products arise from the same two competing Reactions 3 and... 

Oxidation of 2-Methylpropene over Copper Oxide Catalysts in the Presence of Selenium Dioxide... 

The air oxidation of 2-methylpropene to methacrolein was investigated at atmospheric pressure and temperatures ranging between 200° and 460°C. over pumice-supported copper oxide catalyst in the presence of selenium dioxide in an integral isothermal flow reactor. The reaction products were analyzed quantitatively by gas chromatography, and the effects of several process variables on conversion and yield were determined. The experimental results are explained by the electron theory of catalysis on semiconductors, and a reaction mechanism is proposed. It is postulated that while at low selenium-copper ratios, the rate-determining step in the oxidation of 2-methylpropene to methacrolein is a p-type, it is n-type at higher ratios. 

This paper reports the effect of various amounts of selenium dioxide under different operating conditions on the conversion of 2-methylpropene to methacrolein and proposes a hypothesis for the hydrocarbon oxidation, which explains particularly the reactivity and selectivity of selenium-copper oxide catalysts in oxidizing 2-methylpropene. 

The partial air oxidation of 2-methylpropene to methacrolein in a constant and continuous supply of selenium dioxide was investigated in an isothermal integral flow reactor, constructed of 316 stainless steel. The schematic diagram of the apparatus used to study the reaction is shown in Figure 1. 

Extending the definition of n-type and p-type reactions, as defined by Vol kenshtein (21) to the electron transfer step, it would seem that the only reaction given by Equation 1 is a p-type reaction. This reaction would be accelerated by the increase in the value of free hole concentration. On the other hand, all other reactions besides the one given by Equation 1 are n-type and would be accelerated by the increase in free electron concentration. Hydrocarbon oxidation reactions catalyzed by solid oxides are accompanied by oxidation and reduction of the catalyst and the degree of the stoichiometric disturbance in the semiconductor changes. The catalytic process in the oxidation of 2-methylpropene over copper oxide catalyst in the presence of Se02 can be visualized as ... 

Mann and Rouleau (14) and Shapovalova et al. (18) studied the oxidation of 2-methylpropene to methacrolein in the absence of selenium dioxide, and they found that the oxidation of 2-methylpropene was a surface reaction controlling between adsorbed 2-methylpropene and weakly adsorbed oxygen. However, no theoretical explanation is given for this. 

The rate of formation of water would increase with increased rates of conversion of 2-methylpropene and decrease with decreased rate formation. The yield of water, therefore, increased first and then decreased because of the combined effects of these two processes. On the other hand, if methacrolein is formed by Reaction I and subsequently further oxidized by Reaction II, its yield will depend on the extent of Reactions I and II, and an optimum will exist. In agreement with this, it was found that the optimal amount of selenium dioxide giving the highest selectivity under operating conditions was about 0.7% by weight of the catalyst. 

SAMPLE SOLUTION (a) In hydroboration-oxidation H and OH are introduced with a regioselectivity opposite to that of Markovnikov s rule. In the case of 2-methylpropene, this leads to 2-methyl-1-propanol as the product. 

Methylpropene can be removed from the reaction mixture by distillation and easily is made the principal product by appropriate adjustment of the reaction conditions. If the 2-methylpropene is not removed as it is formed, polymer and oxidation products become important. Sulfuric acid often is an unduly strenuous reagent for dehydration of tertiary alcohols. Potassium hydrogen sulfate, copper sulfate, iodine, phosphoric acid, or phosphorus pentoxide may give better results by causing less polymerization and less oxidative degradation which, with sulfuric acid, results in the formation of sulfur dioxide. 

Bismuth molybdate catalysts can also cause other allylic oxidations such as the conversion of 2-methylpropene to methacrolein and a-methylstyrene to atropaldehyde, and ammoxidations such as the conversion of 2-methylpropene to methacrylonitrile and a-methylstyrene to atroponitrile.309... 

Murray and Benavali59 have recently reported the preparation of 1-benzoylphenanthrene 9,10-oxide (125) by photolysis in the presence of oxygen of 1-phenanthrylphenyldiazomethane (126) and also-by ozonolysis of 1-(1-phenanthryl)-l-phenyl-2-methylpropene (127) in 7 and 4% yield, respectively. The carbonyl oxide 128, formed in both cases, reacts intramolecularly to give 125. 

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