F 2-Methylpropene

AS°f (2-methylpropene) = 74.5 cal T mol" . This leads for the reaction to AH° = - 21.35 kcal mol and AS° = 36.5 cal T mol . The reaction of elimination of methyl formate followed by further cleavage of the backbone with formation of 2-methylpropene and 2-methyl-1,3-butadiene is not excluded since methyl formate is generated in the pyrolysate. However, methyl formate is present in very low level, even lower than that of 2-methypropene or 2-methyi-1,3-butadiene, The reaction of methyl formate elimination is shown schematically below ... 

H. Cheradame, J. Habimana de la Croix, E. Rousset, and F.J. Chen, Synthesis of polymers containing pseudohalide groups by cationic polymerization. 9. Azido end-capped poly(2-methylpropene) by polymerization initiated by the system lewis acid-2-azido-2-phenylpropane, Macromolecules, 27(3) 631-637, January 1994. 

Nickel at 100 C is a much more efficient catalyst than palladium in the catalytic reduction of vinylic C-F bonds in perfluoro(2-methylpropene) (21). It is thought that the reduction takes place via the following reaction sequence addition of hydrogen to the C = C bond, elimination of hydrogen fluoride, and then addition of hydrogen to the new C = C bond.26... 

Tennakoon et al. (465) have studied, by conventional 13C NMR, the catalyzed conversion of 2-methylpropene (isobutene) to t-butanol (R = H) or to methyl-f-butyl ether i.e., 2-methyl-2-methoxy-propane (R = CH3) by... 

Al3+-exchanged synthetic hectorite is a good catalyst for these conversions, and the 13C NMR spectrum obtained in the interlamellar, proton-catalyzed addition of water to 2-methylpropene is indistinguishable (Fig. 79) from that of f-butanol. Doubtless studies of this kind, where natural-abundance, 3C NMR signals are used to probe the chemical identity and motional freedom of reactant and product species situated in the interlamellar spaces of clays or pillared clays (see below), will become increasingly popular. Using l3C NMR linewidths and spin-lattice relaxation studies, Matsumoto et al. (466) have succeeded in discriminating between the internal and external surfaces of pillared montmorillonites. 

What properties would we expect for polypropene If we extrapolate from the properties of polyethene, -f-CH2—CH2T , Tm = 130° and Tu =—120°, and poly-2-methylpropene-f-CH2—C(CH3)2-)jj, which is amorphous with... 

Methyl ferf-butyl ether (Problem 8.71) is prepared by reaction of methanol (AH°f = —238.7kj/mol) with 2-methylpropene, according to the equation... 

Iron—manganese alloy, see Ferromanganese, 4383 f Iron pentacarbonyl, see Pentacarbonyliron, 1808a Iron pyrites, see Iron disulfide, 4395 Iron—silicon alloy, see Ferrosilicon, 4384 Iron—titanium alloy, see Ferrotitanium, 4385 t Isobutene, see 2-Methylpropene, 1577 t Isobutyl acetate, 2496... 

This is essentially the procedure actually followed. Alkylation was effected, however, not with te/f-butyl chloride and aluminum chloride but with 2-methylpropene and phosphoric acid. 

The product (benzyl f-butyl ether) is primary on the benzyl side and tertiary on the t-butyl side. So, an SN2 type displacement by potassium f-butoxide of benzyl bromide is one approach, and an acid-catalyzed (SN1) process of benzyl alcohol with isobutylene (2-methylpropene) is another method ... 

Similarly, benzo[6]thiophene also yields mixtures of 2- and 3-alkyl derivatives on alkylation with alkenes or alkanols in the presence of acids <70AHC(11)177). Thus with isopropyl chloride, isopropanol or propene, mixtures of 2- and 3-isopropyl derivatives are formed. Alkylation by 2-methylpropene in the presence of PPA gives 2-t-butyl- (22%) and 3-f-butyl-(71%) benzo[6]thiophenes with t-butanol and cone. H2SO4, the yields are 2-t-butyl (6%) and 3-t-butyl (89%) <72JCS(P1)414>. 

Polymerization of 2-methylpropene is not initiated by hydrofluoric acid alone. In the presence of TiCl4, polymerization is very rapid even at low temperatures [94], Termination by the F counter-ion is prevented by its complexation with TiCl4. The basicity of the TiCl4F anion is low, and this anion as such does not combine with the growing cation. 

The carbocation electrophile in a Friedel-Crafts reaction can be generated in w ays other than by reaction of an alkyl chloride with. AlCF. For example, reaction of benzene with 2-methylpropene in the presence of H3PO4 yields fc / f-butylbenzene. Propose a mechanism for this reaction. 

Addition to six-membered oxygen heterocycles is also common. The photocycloaddition of 5,7-dimethoxycoumarin to tetramethylethylene has been described, and 4-hydroxycoumarin (326) undergoes facile addition to cyclohexene on direct irradiation to give the cyclobutane (327) analogous additions to a variety of other alkenes have been reported, and the cycloaddition of 4-methoxycoumarin to 2-methylpropene has been employed in a synthesis of l,2-dihydrocyclobuta[c]coumarin. Photoaddition of the 1,2-bisenol lactone (328) to trans-stilbene yields propellane (329), and [ 2 -F, 2] cycloaddition is observed along with other competing photoreactions on irradiation of chromone in the presence of alkenes. ... 

Fluoronitroso compounds can be prepared by the simultaneous addition of F and NO to alkene double bonds by the use of either nitrosyl fluoridc317 -,1 9--,22-329 342 344 or a mixture of dinitrogen tetroxide and potassium fluoride.320 The nitrosofluorination reactions of hexa-fluoropropene, perfluoro(2-methylpropene) and perfluorocyclobutene by these two different methods are summarized in Table 27. Additionally, the reactions of nitrosyl fluoride with chloro-trifluoroethene,319 with alkyl perfluorovinyl ethers,317 and with perfluoro(2-methylacryloyl fluoride)344 are listed. 

CHLORO-2-METHYLPROPENE (563-47-3) Forms explosive mixture with air (flash point 11°F/-12°C cc). Slowly hydrolyzes in water, forming methallyl alcohol and hydrochloric acid. Strong oxidizers may cause fire and explosions. Contact with acids or acid fumes produces highly toxic chloride fumes. Aqueous solution is incompatible with sulfuric acid, alkalis, ammonia, aliphatic amines, alkanolamines, alkylene oxides, amides, boranes, epichlorohydrin, nitromethane, organic anhydrides, isocyanates, vinyl acetate. In the presence of moisture, attacks metals can cause pitting and stress corrosion in austenitic stainless steels. 

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